Adding upstream version 18.2.2.upstream/18.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

32 files changed, 10275 insertions, 0 deletions

diff --git a/src/zstd/programs/.gitignore b/src/zstd/programs/.gitignore
new file mode 100644
index 000000000..662f70839
--- /dev/null
+++ b/src/zstd/programs/.gitignore
@@ -0,0 +1,38 @@
+# local binary (Makefile)
+zstd
+zstd32
+zstd4
+zstd-compress
+zstd-decompress
+zstd-frugal
+zstd-small
+zstd-nolegacy
+zstd-dictBuilder
+
+# Object files
+*.o
+*.ko
+default.profraw
+have_zlib
+
+# Executables
+*.exe
+*.out
+*.app
+
+# Default result files
+dictionary
+grillResults.txt
+_*
+tmp*
+*.zst
+result
+out
+
+# fuzzer
+afl
+
+# Misc files
+*.bat
+!windres/generate_res.bat
+dirTest*
diff --git a/src/zstd/programs/BUCK b/src/zstd/programs/BUCK
new file mode 100644
index 000000000..d2aa6373f
--- /dev/null
+++ b/src/zstd/programs/BUCK
@@ -0,0 +1,44 @@
+cxx_binary(
+    name='zstd',
+    headers=glob(['*.h'], excludes=['datagen.h', 'platform.h', 'util.h']),
+    srcs=glob(['*.c'], excludes=['datagen.c']),
+    deps=[
+        ':datagen',
+        ':util',
+        '//lib:zstd',
+        '//lib:zdict',
+        '//lib:mem',
+        '//lib:xxhash',
+    ],
+    preprocessor_flags=[
+        '-DZSTD_GZCOMPRESS',
+        '-DZSTD_GZDECOMPRESS',
+        '-DZSTD_LZMACOMPRESS',
+        '-DZSTD_LZMADECOMPRES',
+        '-DZSTD_LZ4COMPRESS',
+        '-DZSTD_LZ4DECOMPRES',
+    ],
+    linker_flags=[
+        '-lz',
+        '-llzma',
+        '-llz4',
+    ],
+)
+
+cxx_library(
+    name='datagen',
+    visibility=['PUBLIC'],
+    header_namespace='',
+    exported_headers=['datagen.h'],
+    srcs=['datagen.c'],
+    deps=['//lib:mem'],
+)
+
+
+cxx_library(
+    name='util',
+    visibility=['PUBLIC'],
+    header_namespace='',
+    exported_headers=['util.h', 'platform.h'],
+    deps=['//lib:mem'],
+)
diff --git a/src/zstd/programs/Makefile b/src/zstd/programs/Makefile
new file mode 100644
index 000000000..418ad4e63
--- /dev/null
+++ b/src/zstd/programs/Makefile
@@ -0,0 +1,409 @@
+# ################################################################
+# Copyright (c) 2015-2020, Yann Collet, Facebook, Inc.
+# All rights reserved.
+#
+# This source code is licensed under both the BSD-style license (found in the
+# LICENSE file in the root directory of this source tree) and the GPLv2 (found
+# in the COPYING file in the root directory of this source tree).
+# You may select, at your option, one of the above-listed licenses.
+# ##########################################################################
+# zstd : Command Line Utility, supporting gzip-like arguments
+# zstd32 : Same as zstd, but forced to compile in 32-bits mode
+# zstd_nolegacy : zstd without support of decompression of legacy versions
+# zstd-small : minimal zstd without dictionary builder and benchmark
+# zstd-compress : compressor-only version of zstd
+# zstd-decompress : decompressor-only version of zstd
+# ##########################################################################
+
+ZSTDDIR = ../lib
+
+# Version numbers
+LIBVER_SRC := $(ZSTDDIR)/zstd.h
+LIBVER_MAJOR_SCRIPT:=`sed -n '/define ZSTD_VERSION_MAJOR/s/.*[[:blank:]]\([0-9][0-9]*\).*/\1/p' < $(LIBVER_SRC)`
+LIBVER_MINOR_SCRIPT:=`sed -n '/define ZSTD_VERSION_MINOR/s/.*[[:blank:]]\([0-9][0-9]*\).*/\1/p' < $(LIBVER_SRC)`
+LIBVER_PATCH_SCRIPT:=`sed -n '/define ZSTD_VERSION_RELEASE/s/.*[[:blank:]]\([0-9][0-9]*\).*/\1/p' < $(LIBVER_SRC)`
+LIBVER_SCRIPT:= $(LIBVER_MAJOR_SCRIPT).$(LIBVER_MINOR_SCRIPT).$(LIBVER_PATCH_SCRIPT)
+LIBVER_MAJOR := $(shell echo $(LIBVER_MAJOR_SCRIPT))
+LIBVER_MINOR := $(shell echo $(LIBVER_MINOR_SCRIPT))
+LIBVER_PATCH := $(shell echo $(LIBVER_PATCH_SCRIPT))
+LIBVER  := $(shell echo $(LIBVER_SCRIPT))
+
+ZSTD_VERSION = $(LIBVER)
+
+HAVE_COLORNEVER = $(shell echo a | grep --color=never a > /dev/null 2> /dev/null && echo 1 || echo 0)
+GREP_OPTIONS ?=
+ifeq ($HAVE_COLORNEVER, 1)
+GREP_OPTIONS += --color=never
+endif
+GREP = grep $(GREP_OPTIONS)
+
+ifeq ($(shell $(CC) -v 2>&1 | $(GREP) -c "gcc version "), 1)
+ALIGN_LOOP = -falign-loops=32
+else
+ALIGN_LOOP =
+endif
+
+CPPFLAGS+= -DXXH_NAMESPACE=ZSTD_
+ifeq ($(OS),Windows_NT)   # MinGW assumed
+CPPFLAGS   += -D__USE_MINGW_ANSI_STDIO   # compatibility with %zu formatting
+endif
+CFLAGS  ?= -O3
+DEBUGFLAGS+=-Wall -Wextra -Wcast-qual -Wcast-align -Wshadow \
+            -Wstrict-aliasing=1 -Wswitch-enum -Wdeclaration-after-statement \
+            -Wstrict-prototypes -Wundef -Wpointer-arith \
+            -Wvla -Wformat=2 -Winit-self -Wfloat-equal -Wwrite-strings \
+            -Wredundant-decls -Wmissing-prototypes -Wc++-compat
+CFLAGS  += $(DEBUGFLAGS) $(MOREFLAGS)
+FLAGS    = $(CPPFLAGS) $(CFLAGS) $(LDFLAGS)
+
+
+ZSTDCOMMON_FILES := $(ZSTDDIR)/common/*.c
+ZSTDCOMP_FILES := $(ZSTDDIR)/compress/*.c
+ZSTDDECOMP_FILES := $(ZSTDDIR)/decompress/*.c
+ZSTD_FILES := $(ZSTDDECOMP_FILES) $(ZSTDCOMMON_FILES) $(ZSTDCOMP_FILES)
+ZDICT_FILES := $(ZSTDDIR)/dictBuilder/*.c
+ZSTDDECOMP_O = $(ZSTDDIR)/decompress/zstd_decompress.o
+
+ZSTD_LEGACY_SUPPORT ?= 5
+ZSTDLEGACY_FILES :=
+ifneq ($(ZSTD_LEGACY_SUPPORT), 0)
+ifeq ($(shell test $(ZSTD_LEGACY_SUPPORT) -lt 8; echo $$?), 0)
+	ZSTDLEGACY_FILES += $(shell ls $(ZSTDDIR)/legacy/*.c | $(GREP) 'v0[$(ZSTD_LEGACY_SUPPORT)-7]')
+endif
+else
+endif
+
+# Sort files in alphabetical order for reproducible builds
+ZSTDLIB_FILES := $(sort $(wildcard $(ZSTD_FILES)) $(wildcard $(ZSTDLEGACY_FILES)) $(wildcard $(ZDICT_FILES)))
+
+ZSTD_CLI_FILES := $(wildcard *.c)
+ZSTD_CLI_OBJ := $(patsubst %.c,%.o,$(ZSTD_CLI_FILES))
+
+# Define *.exe as extension for Windows systems
+ifneq (,$(filter Windows%,$(OS)))
+EXT =.exe
+RES64_FILE = windres/zstd64.res
+RES32_FILE = windres/zstd32.res
+ifneq (,$(filter x86_64%,$(shell $(CC) -dumpmachine)))
+    RES_FILE = $(RES64_FILE)
+else
+    RES_FILE = $(RES32_FILE)
+endif
+else
+EXT =
+endif
+
+VOID = /dev/null
+
+# Make 4.3 doesn't support '\#' anymore (https://lwn.net/Articles/810071/)
+NUM_SYMBOL := \#
+
+# thread detection
+NO_THREAD_MSG := ==> no threads, building without multithreading support
+HAVE_PTHREAD := $(shell printf '$(NUM_SYMBOL)include <pthread.h>\nint main(void) { return 0; }' > have_pthread.c && $(CC) $(FLAGS) -o have_pthread$(EXT) have_pthread.c -pthread 2> $(VOID) && rm have_pthread$(EXT) && echo 1 || echo 0; rm have_pthread.c)
+HAVE_THREAD := $(shell [ "$(HAVE_PTHREAD)" -eq "1" -o -n "$(filter Windows%,$(OS))" ] && echo 1 || echo 0)
+ifeq ($(HAVE_THREAD), 1)
+THREAD_MSG := ==> building with threading support
+THREAD_CPP := -DZSTD_MULTITHREAD
+THREAD_LD := -pthread
+else
+THREAD_MSG := $(NO_THREAD_MSG)
+endif
+
+# zlib detection
+NO_ZLIB_MSG := ==> no zlib, building zstd without .gz support
+HAVE_ZLIB := $(shell printf '$(NUM_SYMBOL)include <zlib.h>\nint main(void) { return 0; }' > have_zlib.c && $(CC) $(FLAGS) -o have_zlib$(EXT) have_zlib.c -lz 2> $(VOID) && rm have_zlib$(EXT) && echo 1 || echo 0; rm have_zlib.c)
+ifeq ($(HAVE_ZLIB), 1)
+ZLIB_MSG := ==> building zstd with .gz compression support
+ZLIBCPP = -DZSTD_GZCOMPRESS -DZSTD_GZDECOMPRESS
+ZLIBLD = -lz
+else
+ZLIB_MSG := $(NO_ZLIB_MSG)
+endif
+
+# lzma detection
+NO_LZMA_MSG := ==> no liblzma, building zstd without .xz/.lzma support
+HAVE_LZMA := $(shell printf '$(NUM_SYMBOL)include <lzma.h>\nint main(void) { return 0; }' > have_lzma.c && $(CC) $(FLAGS) -o have_lzma$(EXT) have_lzma.c -llzma 2> $(VOID) && rm have_lzma$(EXT) && echo 1 || echo 0; rm have_lzma.c)
+ifeq ($(HAVE_LZMA), 1)
+LZMA_MSG := ==> building zstd with .xz/.lzma compression support
+LZMACPP = -DZSTD_LZMACOMPRESS -DZSTD_LZMADECOMPRESS
+LZMALD = -llzma
+else
+LZMA_MSG := $(NO_LZMA_MSG)
+endif
+
+# lz4 detection
+NO_LZ4_MSG := ==> no liblz4, building zstd without .lz4 support
+HAVE_LZ4 := $(shell printf '$(NUM_SYMBOL)include <lz4frame.h>\n$(NUM_SYMBOL)include <lz4.h>\nint main(void) { return 0; }' > have_lz4.c && $(CC) $(FLAGS) -o have_lz4$(EXT) have_lz4.c -llz4 2> $(VOID) && rm have_lz4$(EXT) && echo 1 || echo 0; rm have_lz4.c)
+ifeq ($(HAVE_LZ4), 1)
+LZ4_MSG := ==> building zstd with .lz4 compression support
+LZ4CPP = -DZSTD_LZ4COMPRESS -DZSTD_LZ4DECOMPRESS
+LZ4LD = -llz4
+else
+LZ4_MSG := $(NO_LZ4_MSG)
+endif
+
+# explicit backtrace enable/disable for Linux & Darwin
+ifeq ($(BACKTRACE), 0)
+DEBUGFLAGS += -DBACKTRACE_ENABLE=0
+endif
+ifeq (,$(filter Windows%, $(OS)))
+ifeq ($(BACKTRACE), 1)
+DEBUGFLAGS += -DBACKTRACE_ENABLE=1
+DEBUGFLAGS_LD += -rdynamic
+endif
+endif
+
+
+.PHONY: default
+default: zstd-release
+
+.PHONY: all
+all: zstd
+
+.PHONY: allVariants
+allVariants: zstd zstd-compress zstd-decompress zstd-small zstd-nolegacy zstd-dictBuilder
+
+$(ZSTDDECOMP_O): CFLAGS += $(ALIGN_LOOP)
+
+zstd : CPPFLAGS += $(THREAD_CPP) $(ZLIBCPP) $(LZMACPP) $(LZ4CPP)
+zstd : LDFLAGS += $(THREAD_LD) $(ZLIBLD) $(LZMALD) $(LZ4LD) $(DEBUGFLAGS_LD)
+zstd : CPPFLAGS += -DZSTD_LEGACY_SUPPORT=$(ZSTD_LEGACY_SUPPORT)
+ifneq (,$(filter Windows%,$(OS)))
+zstd : $(RES_FILE)
+endif
+zstd : $(ZSTDLIB_FILES) $(ZSTD_CLI_OBJ)
+	@echo "$(THREAD_MSG)"
+	@echo "$(ZLIB_MSG)"
+	@echo "$(LZMA_MSG)"
+	@echo "$(LZ4_MSG)"
+	$(CC) $(FLAGS) $^ -o $@$(EXT) $(LDFLAGS)
+
+.PHONY: zstd-release
+zstd-release: DEBUGFLAGS := -DBACKTRACE_ENABLE=0
+zstd-release: DEBUGFLAGS_LD :=
+zstd-release: zstd
+
+zstd32 : CPPFLAGS += $(THREAD_CPP)
+zstd32 : LDFLAGS  += $(THREAD_LD)
+zstd32 : CPPFLAGS += -DZSTD_LEGACY_SUPPORT=$(ZSTD_LEGACY_SUPPORT)
+ifneq (,$(filter Windows%,$(OS)))
+zstd32 : $(RES32_FILE)
+endif
+zstd32 : $(ZSTDLIB_FILES) $(ZSTD_CLI_FILES)
+	$(CC) -m32 $(FLAGS) $^ -o $@$(EXT)
+
+## zstd-nolegacy: same scope as zstd, with just support of legacy formats removed
+zstd-nolegacy : LDFLAGS += $(THREAD_LD) $(ZLIBLD) $(LZMALD) $(LZ4LD) $(DEBUGFLAGS_LD)
+zstd-nolegacy : $(ZSTD_FILES) $(ZDICT_FILES) $(ZSTD_CLI_OBJ)
+	$(CC) $(FLAGS) $^ -o $@$(EXT) $(LDFLAGS)
+
+zstd-nomt : THREAD_CPP :=
+zstd-nomt : THREAD_LD  :=
+zstd-nomt : THREAD_MSG := - multi-threading disabled
+zstd-nomt : zstd
+
+zstd-nogz : ZLIBCPP :=
+zstd-nogz : ZLIBLD  :=
+zstd-nogz : ZLIB_MSG := - gzip support is disabled
+zstd-nogz : zstd
+
+zstd-noxz : LZMACPP :=
+zstd-noxz : LZMALD  :=
+zstd-noxz : LZMA_MSG := - xz/lzma support is disabled
+zstd-noxz : zstd
+
+## zstd-dll: zstd executable linked to dynamic library libzstd (must already exist)
+# note : the following target doesn't link
+#        because zstd uses non-public symbols from libzstd
+#        such as XXH64 (for benchmark),
+#        ZDICT_trainFromBuffer_unsafe_legacy (for dictionary builder)
+#        and ZSTD_cycleLog (likely for --patch-from).
+#        It's unclear at this stage if this is a scenario that must be supported
+.PHONY: zstd-dll
+zstd-dll : LDFLAGS+= -L$(ZSTDDIR) -lzstd
+zstd-dll : ZSTDLIB_FILES =
+zstd-dll : $(ZSTD_CLI_OBJ)
+	$(CC) $(FLAGS) $^ -o $@$(EXT) $(LDFLAGS)
+
+
+## zstd-pgo: zstd executable optimized with pgo. `gcc` only.
+zstd-pgo :
+	$(MAKE) clean
+	$(MAKE) zstd MOREFLAGS=-fprofile-generate
+	./zstd -b19i1 $(PROFILE_WITH)
+	./zstd -b16i1 $(PROFILE_WITH)
+	./zstd -b9i2 $(PROFILE_WITH)
+	./zstd -b $(PROFILE_WITH)
+	./zstd -b7i2 $(PROFILE_WITH)
+	./zstd -b5 $(PROFILE_WITH)
+	$(RM) zstd *.o $(ZSTDDECOMP_O) $(ZSTDDIR)/compress/*.o
+	case $(CC) in *clang*) if ! [ -e default.profdata ]; then llvm-profdata merge -output=default.profdata default*.profraw; fi ;; esac
+	$(MAKE) zstd MOREFLAGS=-fprofile-use
+
+## zstd-small: minimal target, supporting only zstd compression and decompression. no bench. no legacy. no other format.
+zstd-small: CFLAGS = -Os -s
+zstd-frugal zstd-small: $(ZSTD_FILES) zstdcli.c util.c timefn.c fileio.c
+	$(CC) $(FLAGS) -DZSTD_NOBENCH -DZSTD_NODICT $^ -o $@$(EXT)
+
+zstd-decompress: $(ZSTDCOMMON_FILES) $(ZSTDDECOMP_FILES) zstdcli.c util.c timefn.c fileio.c
+	$(CC) $(FLAGS) -DZSTD_NOBENCH -DZSTD_NODICT -DZSTD_NOCOMPRESS $^ -o $@$(EXT)
+
+zstd-compress: $(ZSTDCOMMON_FILES) $(ZSTDCOMP_FILES) zstdcli.c util.c timefn.c fileio.c
+	$(CC) $(FLAGS) -DZSTD_NOBENCH -DZSTD_NODICT -DZSTD_NODECOMPRESS $^ -o $@$(EXT)
+
+## zstd-dictBuilder: executable supporting dictionary creation and compression (only)
+zstd-dictBuilder: CPPFLAGS += -DZSTD_NOBENCH -DZSTD_NODECOMPRESS
+zstd-dictBuilder: $(ZSTDCOMMON_FILES) $(ZSTDCOMP_FILES) $(ZDICT_FILES) zstdcli.c util.c timefn.c fileio.c dibio.c
+	$(CC) $(FLAGS) $^ -o $@$(EXT)
+
+zstdmt: zstd
+	ln -sf zstd zstdmt
+
+.PHONY: generate_res
+generate_res: $(RES64_FILE) $(RES32_FILE)
+
+ifneq (,$(filter Windows%,$(OS)))
+RC ?= windres
+# http://stackoverflow.com/questions/708238/how-do-i-add-an-icon-to-a-mingw-gcc-compiled-executable
+$(RES64_FILE): windres/zstd.rc
+	$(RC) -o $@ -I ../lib -I windres -i $< -O coff -F pe-x86-64
+$(RES32_FILE): windres/zstd.rc
+	$(RC) -o $@ -I ../lib -I windres -i $< -O coff -F pe-i386
+endif
+
+.PHONY: clean
+clean:
+	$(MAKE) -C $(ZSTDDIR) clean
+	@$(RM) $(ZSTDDIR)/decompress/*.o $(ZSTDDIR)/decompress/zstd_decompress.gcda
+	@$(RM) core *.o tmp* result* *.gcda dictionary *.zst \
+        zstd$(EXT) zstd32$(EXT) zstd-compress$(EXT) zstd-decompress$(EXT) \
+        zstd-small$(EXT) zstd-frugal$(EXT) zstd-nolegacy$(EXT) zstd4$(EXT) \
+        zstd-dictBuilder$(EXT) *.gcda default*.profraw default.profdata have_zlib$(EXT)
+	@echo Cleaning completed
+
+MD2ROFF = ronn
+MD2ROFF_FLAGS = --roff --warnings --manual="User Commands" --organization="zstd $(ZSTD_VERSION)"
+
+zstd.1: zstd.1.md ../lib/zstd.h
+	cat $< | $(MD2ROFF) $(MD2ROFF_FLAGS) | sed -n '/^\.\\\".*/!p' > $@
+
+zstdgrep.1: zstdgrep.1.md ../lib/zstd.h
+	cat $< | $(MD2ROFF) $(MD2ROFF_FLAGS) | sed -n '/^\.\\\".*/!p' > $@
+
+zstdless.1: zstdless.1.md ../lib/zstd.h
+	cat $< | $(MD2ROFF) $(MD2ROFF_FLAGS) | sed -n '/^\.\\\".*/!p' > $@
+
+.PHONY: man
+man: zstd.1 zstdgrep.1 zstdless.1
+
+.PHONY: clean-man
+clean-man:
+	$(RM) zstd.1
+	$(RM) zstdgrep.1
+	$(RM) zstdless.1
+
+.PHONY: preview-man
+preview-man: clean-man man
+	man ./zstd.1
+	man ./zstdgrep.1
+	man ./zstdless.1
+
+#-----------------------------------------------------------------------------
+# make install is validated only for Linux, macOS, BSD, Hurd and Solaris targets
+#-----------------------------------------------------------------------------
+ifneq (,$(filter $(shell uname),Linux Darwin GNU/kFreeBSD GNU OpenBSD FreeBSD NetBSD DragonFly SunOS Haiku))
+
+HAVE_COLORNEVER = $(shell echo a | egrep --color=never a > /dev/null 2> /dev/null && echo 1 || echo 0)
+EGREP_OPTIONS ?=
+ifeq ($HAVE_COLORNEVER, 1)
+EGREP_OPTIONS += --color=never
+endif
+EGREP = egrep $(EGREP_OPTIONS)
+AWK = awk
+
+# Print a two column output of targets and their description. To add a target description, put a
+# comment in the Makefile with the format "## <TARGET>: <DESCRIPTION>".  For example:
+#
+## list: Print all targets and their descriptions (if provided)
+.PHONY: list
+list:
+	@TARGETS=$$($(MAKE) -pRrq -f $(lastword $(MAKEFILE_LIST)) : 2>/dev/null \
+		| $(AWK) -v RS= -F: '/^# File/,/^# Finished Make data base/ {if ($$1 !~ "^[#.]") {print $$1}}' \
+		| $(EGREP) -v  -e '^[^[:alnum:]]' | sort); \
+	{ \
+	    printf "Target Name\tDescription\n"; \
+	    printf "%0.s-" {1..16}; printf "\t"; printf "%0.s-" {1..40}; printf "\n"; \
+	    for target in $$TARGETS; do \
+	        line=$$($(EGREP) "^##[[:space:]]+$$target:" $(lastword $(MAKEFILE_LIST))); \
+	        description=$$(echo $$line | $(AWK) '{i=index($$0,":"); print substr($$0,i+1)}' | xargs); \
+	        printf "$$target\t$$description\n"; \
+	    done \
+	} | column -t -s $$'\t'
+
+
+DESTDIR     ?=
+# directory variables : GNU conventions prefer lowercase
+# see https://www.gnu.org/prep/standards/html_node/Makefile-Conventions.html
+# support both lower and uppercase (BSD), use uppercase in script
+prefix      ?= /usr/local
+PREFIX      ?= $(prefix)
+exec_prefix ?= $(PREFIX)
+bindir      ?= $(exec_prefix)/bin
+BINDIR      ?= $(bindir)
+datarootdir ?= $(PREFIX)/share
+mandir      ?= $(datarootdir)/man
+man1dir     ?= $(mandir)/man1
+
+ifneq (,$(filter $(shell uname),OpenBSD FreeBSD NetBSD DragonFly SunOS))
+MANDIR  ?= $(PREFIX)/man
+MAN1DIR ?= $(MANDIR)/man1
+else
+MAN1DIR ?= $(man1dir)
+endif
+
+ifneq (,$(filter $(shell uname),SunOS))
+INSTALL ?= ginstall
+else
+INSTALL ?= install
+endif
+
+INSTALL_PROGRAM ?= $(INSTALL)
+INSTALL_SCRIPT  ?= $(INSTALL_PROGRAM)
+INSTALL_DATA    ?= $(INSTALL) -m 644
+INSTALL_MAN     ?= $(INSTALL_DATA)
+
+.PHONY: install
+install: zstd
+	@echo Installing binaries
+	@$(INSTALL) -d -m 755 $(DESTDIR)$(BINDIR)/ $(DESTDIR)$(MAN1DIR)/
+	@$(INSTALL_PROGRAM) zstd$(EXT) $(DESTDIR)$(BINDIR)/zstd$(EXT)
+	@ln -sf zstd$(EXT) $(DESTDIR)$(BINDIR)/zstdcat$(EXT)
+	@ln -sf zstd$(EXT) $(DESTDIR)$(BINDIR)/unzstd$(EXT)
+	@ln -sf zstd$(EXT) $(DESTDIR)$(BINDIR)/zstdmt$(EXT)
+	@$(INSTALL_SCRIPT) zstdless $(DESTDIR)$(BINDIR)/zstdless
+	@$(INSTALL_SCRIPT) zstdgrep $(DESTDIR)$(BINDIR)/zstdgrep
+	@echo Installing man pages
+	@$(INSTALL_MAN) zstd.1 $(DESTDIR)$(MAN1DIR)/zstd.1
+	@ln -sf zstd.1 $(DESTDIR)$(MAN1DIR)/zstdcat.1
+	@ln -sf zstd.1 $(DESTDIR)$(MAN1DIR)/unzstd.1
+	@$(INSTALL_MAN) zstdgrep.1 $(DESTDIR)$(MAN1DIR)/zstdgrep.1
+	@$(INSTALL_MAN) zstdless.1 $(DESTDIR)$(MAN1DIR)/zstdless.1
+	@echo zstd installation completed
+
+.PHONY: uninstall
+uninstall:
+	@$(RM) $(DESTDIR)$(BINDIR)/zstdgrep
+	@$(RM) $(DESTDIR)$(BINDIR)/zstdless
+	@$(RM) $(DESTDIR)$(BINDIR)/zstdcat
+	@$(RM) $(DESTDIR)$(BINDIR)/unzstd
+	@$(RM) $(DESTDIR)$(BINDIR)/zstdmt
+	@$(RM) $(DESTDIR)$(BINDIR)/zstd
+	@$(RM) $(DESTDIR)$(MAN1DIR)/zstdless.1
+	@$(RM) $(DESTDIR)$(MAN1DIR)/zstdgrep.1
+	@$(RM) $(DESTDIR)$(MAN1DIR)/zstdcat.1
+	@$(RM) $(DESTDIR)$(MAN1DIR)/unzstd.1
+	@$(RM) $(DESTDIR)$(MAN1DIR)/zstd.1
+	@echo zstd programs successfully uninstalled
+
+endif
diff --git a/src/zstd/programs/README.md b/src/zstd/programs/README.md
new file mode 100644
index 000000000..53706de72
--- /dev/null
+++ b/src/zstd/programs/README.md
@@ -0,0 +1,279 @@
+Command Line Interface for Zstandard library
+============================================
+
+Command Line Interface (CLI) can be created using the `make` command without any additional parameters.
+There are however other Makefile targets that create different variations of CLI:
+- `zstd` : default CLI supporting gzip-like arguments; includes dictionary builder, benchmark, and support for decompression of legacy zstd formats
+- `zstd_nolegacy` : Same as `zstd` but without support for legacy zstd formats
+- `zstd-small` : CLI optimized for minimal size; no dictionary builder, no benchmark, and no support for legacy zstd formats
+- `zstd-compress` : version of CLI which can only compress into zstd format
+- `zstd-decompress` : version of CLI which can only decompress zstd format
+
+
+### Compilation variables
+`zstd` scope can be altered by modifying the following `make` variables :
+
+- __HAVE_THREAD__ : multithreading is automatically enabled when `pthread` is detected.
+  It's possible to disable multithread support, by setting `HAVE_THREAD=0`.
+  Example : `make zstd HAVE_THREAD=0`
+  It's also possible to force multithread support, using `HAVE_THREAD=1`.
+  In which case, linking stage will fail if neither `pthread` nor `windows.h` library can be found.
+  This is useful to ensure this feature is not silently disabled.
+
+- __ZSTD_LEGACY_SUPPORT__ : `zstd` can decompress files compressed by older versions of `zstd`.
+  Starting v0.8.0, all versions of `zstd` produce frames compliant with the [specification](../doc/zstd_compression_format.md), and are therefore compatible.
+  But older versions (< v0.8.0) produced different, incompatible, frames.
+  By default, `zstd` supports decoding legacy formats >= v0.4.0 (`ZSTD_LEGACY_SUPPORT=4`).
+  This can be altered by modifying this compilation variable.
+  `ZSTD_LEGACY_SUPPORT=1` means "support all formats >= v0.1.0".
+  `ZSTD_LEGACY_SUPPORT=2` means "support all formats >= v0.2.0", and so on.
+  `ZSTD_LEGACY_SUPPORT=0` means _DO NOT_ support any legacy format.
+  if `ZSTD_LEGACY_SUPPORT >= 8`, it's the same as `0`, since there is no legacy format after `7`.
+  Note : `zstd` only supports decoding older formats, and cannot generate any legacy format.
+
+- __HAVE_ZLIB__ : `zstd` can compress and decompress files in `.gz` format.
+  This is ordered through command `--format=gzip`.
+  Alternatively, symlinks named `gzip` or `gunzip` will mimic intended behavior.
+  `.gz` support is automatically enabled when `zlib` library is detected at build time.
+  It's possible to disable `.gz` support, by setting `HAVE_ZLIB=0`.
+  Example : `make zstd HAVE_ZLIB=0`
+  It's also possible to force compilation with zlib support, using `HAVE_ZLIB=1`.
+  In which case, linking stage will fail if `zlib` library cannot be found.
+  This is useful to prevent silent feature disabling.
+
+- __HAVE_LZMA__ : `zstd` can compress and decompress files in `.xz` and `.lzma` formats.
+  This is ordered through commands `--format=xz` and `--format=lzma` respectively.
+  Alternatively, symlinks named `xz`, `unxz`, `lzma`, or `unlzma` will mimic intended behavior.
+  `.xz` and `.lzma` support is automatically enabled when `lzma` library is detected at build time.
+  It's possible to disable `.xz` and `.lzma` support, by setting `HAVE_LZMA=0`.
+  Example : `make zstd HAVE_LZMA=0`
+  It's also possible to force compilation with lzma support, using `HAVE_LZMA=1`.
+  In which case, linking stage will fail if `lzma` library cannot be found.
+  This is useful to prevent silent feature disabling.
+
+- __HAVE_LZ4__ : `zstd` can compress and decompress files in `.lz4` formats.
+  This is ordered through commands `--format=lz4`.
+  Alternatively, symlinks named `lz4`, or `unlz4` will mimic intended behavior.
+  `.lz4` support is automatically enabled when `lz4` library is detected at build time.
+  It's possible to disable `.lz4` support, by setting `HAVE_LZ4=0` .
+  Example : `make zstd HAVE_LZ4=0`
+  It's also possible to force compilation with lz4 support, using `HAVE_LZ4=1`.
+  In which case, linking stage will fail if `lz4` library cannot be found.
+  This is useful to prevent silent feature disabling.
+
+- __ZSTD_NOBENCH__ : `zstd` cli will be compiled without its integrated benchmark module.
+  This can be useful to produce smaller binaries.
+  In this case, the corresponding unit can also be excluded from compilation target.
+
+- __ZSTD_NODICT__ : `zstd` cli will be compiled without support for the integrated dictionary builder.
+  This can be useful to produce smaller binaries.
+  In this case, the corresponding unit can also be excluded from compilation target.
+
+- __ZSTD_NOCOMPRESS__ : `zstd` cli will be compiled without support for compression.
+  The resulting binary will only be able to decompress files.
+  This can be useful to produce smaller binaries.
+  A corresponding `Makefile` target using this ability is `zstd-decompress`.
+
+- __ZSTD_NODECOMPRESS__ : `zstd` cli will be compiled without support for decompression.
+  The resulting binary will only be able to compress files.
+  This can be useful to produce smaller binaries.
+  A corresponding `Makefile` target using this ability is `zstd-compress`.
+
+- __BACKTRACE__ : `zstd` can display a stack backtrace when execution
+  generates a runtime exception. By default, this feature may be
+  degraded/disabled on some platforms unless additional compiler directives are
+  applied. When triaging a runtime issue, enabling this feature can provide
+  more context to determine the location of the fault.
+  Example : `make zstd BACKTRACE=1`
+
+
+### Aggregation of parameters
+CLI supports aggregation of parameters i.e. `-b1`, `-e18`, and `-i1` can be joined into `-b1e18i1`.
+
+
+### Symlink shortcuts
+It's possible to invoke `zstd` through a symlink.
+When the name of the symlink has a specific value, it triggers an associated behavior.
+- `zstdmt` : compress using all cores available on local system.
+- `zcat` : will decompress and output target file using any of the supported formats. `gzcat` and `zstdcat` are also equivalent.
+- `gzip` : if zlib support is enabled, will mimic `gzip` by compressing file using `.gz` format, removing source file by default (use `--keep` to preserve). If zlib is not supported, triggers an error.
+- `xz` : if lzma support is enabled, will mimic `xz` by compressing file using `.xz` format, removing source file by default (use `--keep` to preserve). If xz is not supported, triggers an error.
+- `lzma` : if lzma support is enabled, will mimic `lzma` by compressing file using `.lzma` format, removing source file by default (use `--keep` to preserve). If lzma is not supported, triggers an error.
+- `lz4` : if lz4 support is enabled, will mimic `lz4` by compressing file using `.lz4` format. If lz4 is not supported, triggers an error.
+- `unzstd` and `unlz4` will decompress any of the supported format.
+- `ungz`, `unxz` and `unlzma` will do the same, and will also remove source file by default (use `--keep` to preserve).
+
+
+### Dictionary builder in Command Line Interface
+Zstd offers a training mode, which can be used to tune the algorithm for a selected
+type of data, by providing it with a few samples. The result of the training is stored
+in a file selected with the `-o` option (default name is `dictionary`),
+which can be loaded before compression and decompression.
+
+Using a dictionary, the compression ratio achievable on small data improves dramatically.
+These compression gains are achieved while simultaneously providing faster compression and decompression speeds.
+Dictionary work if there is some correlation in a family of small data (there is no universal dictionary).
+Hence, deploying one dictionary per type of data will provide the greater benefits.
+Dictionary gains are mostly effective in the first few KB. Then, the compression algorithm
+will rely more and more on previously decoded content to compress the rest of the file.
+
+Usage of the dictionary builder and created dictionaries with CLI:
+
+1. Create the dictionary : `zstd --train PathToTrainingSet/* -o dictionaryName`
+2. Compress with the dictionary: `zstd FILE -D dictionaryName`
+3. Decompress with the dictionary: `zstd --decompress FILE.zst -D dictionaryName`
+
+
+### Benchmark in Command Line Interface
+CLI includes in-memory compression benchmark module for zstd.
+The benchmark is conducted using given filenames. The files are read into memory and joined together.
+It makes benchmark more precise as it eliminates I/O overhead.
+Multiple filenames can be supplied, as multiple parameters, with wildcards,
+or names of directories can be used as parameters with `-r` option.
+
+The benchmark measures ratio, compressed size, compression and decompression speed.
+One can select compression levels starting from `-b` and ending with `-e`.
+The `-i` parameter selects minimal time used for each of tested levels.
+
+
+### Usage of Command Line Interface
+The full list of options can be obtained with `-h` or `-H` parameter:
+```
+Usage :
+      zstd [args] [FILE(s)] [-o file]
+
+FILE    : a filename
+          with no FILE, or when FILE is - , read standard input
+Arguments :
+ -#     : # compression level (1-19, default: 3)
+ -d     : decompression
+ -D file: use `file` as Dictionary
+ -o file: result stored into `file` (only if 1 input file)
+ -f     : overwrite output without prompting and (de)compress links
+--rm    : remove source file(s) after successful de/compression
+ -k     : preserve source file(s) (default)
+ -h/-H  : display help/long help and exit
+
+Advanced arguments :
+ -V     : display Version number and exit
+ -v     : verbose mode; specify multiple times to increase verbosity
+ -q     : suppress warnings; specify twice to suppress errors too
+ -c     : force write to standard output, even if it is the console
+ -l     : print information about zstd compressed files
+--exclude-compressed:  only compress files that are not previously compressed
+--ultra : enable levels beyond 19, up to 22 (requires more memory)
+--long[=#]: enable long distance matching with given window log (default: 27)
+--fast[=#]: switch to very fast compression levels (default: 1)
+--adapt : dynamically adapt compression level to I/O conditions
+--stream-size=# : optimize compression parameters for streaming input of given number of bytes
+--size-hint=# optimize compression parameters for streaming input of approximately this size
+--target-compressed-block-size=# : make compressed block near targeted size
+ -T#    : spawns # compression threads (default: 1, 0==# cores)
+ -B#    : select size of each job (default: 0==automatic)
+--rsyncable : compress using a rsync-friendly method (-B sets block size)
+--no-dictID : don't write dictID into header (dictionary compression)
+--[no-]check : integrity check (default: enabled)
+--[no-]compress-literals : force (un)compressed literals
+ -r     : operate recursively on directories
+--output-dir-flat[=directory]: all resulting files stored into `directory`.
+--format=zstd : compress files to the .zst format (default)
+--format=gzip : compress files to the .gz format
+--test  : test compressed file integrity
+--[no-]sparse : sparse mode (default: disabled)
+ -M#    : Set a memory usage limit for decompression
+--no-progress : do not display the progress bar
+--      : All arguments after "--" are treated as files
+
+Dictionary builder :
+--train ## : create a dictionary from a training set of files
+--train-cover[=k=#,d=#,steps=#,split=#,shrink[=#]] : use the cover algorithm with optional args
+--train-fastcover[=k=#,d=#,f=#,steps=#,split=#,accel=#,shrink[=#]] : use the fast cover algorithm with optional args
+--train-legacy[=s=#] : use the legacy algorithm with selectivity (default: 9)
+ -o file : `file` is dictionary name (default: dictionary)
+--maxdict=# : limit dictionary to specified size (default: 112640)
+--dictID=# : force dictionary ID to specified value (default: random)
+
+Benchmark arguments :
+ -b#    : benchmark file(s), using # compression level (default: 3)
+ -e#    : test all compression levels from -bX to # (default: 1)
+ -i#    : minimum evaluation time in seconds (default: 3s)
+ -B#    : cut file into independent blocks of size # (default: no block)
+--priority=rt : set process priority to real-time
+```
+
+### Passing parameters through Environment Variables
+`ZSTD_CLEVEL` can be used to modify the default compression level of `zstd`
+(usually set to `3`) to another value between 1 and 19 (the "normal" range).
+This can be useful when `zstd` CLI is invoked in a way that doesn't allow passing arguments.
+One such scenario is `tar --zstd`.
+As `ZSTD_CLEVEL` only replaces the default compression level,
+it can then be overridden by corresponding command line arguments.
+
+There is no "generic" way to pass "any kind of parameter" to `zstd` in a pass-through manner.
+Using environment variables for this purpose has security implications.
+Therefore, this avenue is intentionally restricted and only supports `ZSTD_CLEVEL`.
+
+### Long distance matching mode
+The long distance matching mode, enabled with `--long`, is designed to improve
+the compression ratio for files with long matches at a large distance (up to the
+maximum window size, `128 MiB`) while still maintaining compression speed.
+
+Enabling this mode sets the window size to `128 MiB` and thus increases the memory
+usage for both the compressor and decompressor. Performance in terms of speed is
+dependent on long matches being found. Compression speed may degrade if few long
+matches are found. Decompression speed usually improves when there are many long
+distance matches.
+
+Below are graphs comparing the compression speed, compression ratio, and
+decompression speed with and without long distance matching on an ideal use
+case: a tar of four versions of clang (versions `3.4.1`, `3.4.2`, `3.5.0`,
+`3.5.1`) with a total size of `244889600 B`. This is an ideal use case as there
+are many long distance matches within the maximum window size of `128 MiB` (each
+version is less than `128 MiB`).
+
+Compression Speed vs Ratio | Decompression Speed
+---------------------------|---------------------
+![Compression Speed vs Ratio](https://raw.githubusercontent.com/facebook/zstd/v1.3.3/doc/images/ldmCspeed.png "Compression Speed vs Ratio") | ![Decompression Speed](https://raw.githubusercontent.com/facebook/zstd/v1.3.3/doc/images/ldmDspeed.png "Decompression Speed")
+
+| Method | Compression ratio | Compression speed | Decompression speed  |
+|:-------|------------------:|-------------------------:|---------------------------:|
+| `zstd -1`  | `5.065`    | `284.8 MB/s`  | `759.3 MB/s`  |
+| `zstd -5`  | `5.826`    | `124.9 MB/s`  | `674.0 MB/s`  |
+| `zstd -10` | `6.504`    | `29.5 MB/s`   | `771.3 MB/s`  |
+| `zstd -1 --long` | `17.426` | `220.6 MB/s` | `1638.4 MB/s` |
+| `zstd -5 --long` | `19.661` | `165.5 MB/s` | `1530.6 MB/s` |
+| `zstd -10 --long`| `21.949` |  `75.6 MB/s` | `1632.6 MB/s` |
+
+On this file, the compression ratio improves significantly with minimal impact
+on compression speed, and the decompression speed doubles.
+
+On the other extreme, compressing a file with few long distance matches (such as
+the [Silesia compression corpus]) will likely lead to a deterioration in
+compression speed (for lower levels) with minimal change in compression ratio.
+
+The below table illustrates this on the [Silesia compression corpus].
+
+[Silesia compression corpus]: http://sun.aei.polsl.pl/~sdeor/index.php?page=silesia
+
+| Method | Compression ratio | Compression speed | Decompression speed  |
+|:-------|------------------:|------------------:|---------------------:|
+| `zstd -1`        | `2.878` | `231.7 MB/s`      | `594.4 MB/s`   |
+| `zstd -1 --long` | `2.929` | `106.5 MB/s`      | `517.9 MB/s`   |
+| `zstd -5`        | `3.274` | `77.1 MB/s`       | `464.2 MB/s`   |
+| `zstd -5 --long` | `3.319` | `51.7 MB/s`       | `371.9 MB/s`   |
+| `zstd -10`       | `3.523` | `16.4 MB/s`       | `489.2 MB/s`   |
+| `zstd -10 --long`| `3.566` | `16.2 MB/s`       | `415.7 MB/s`   |
+
+
+### zstdgrep
+
+`zstdgrep` is a utility which makes it possible to `grep` directly a `.zst` compressed file.
+It's used the same way as normal `grep`, for example :
+`zstdgrep pattern file.zst`
+
+`zstdgrep` is _not_ compatible with dictionary compression.
+
+To search into a file compressed with a dictionary,
+it's necessary to decompress it using `zstd` or `zstdcat`,
+and then pipe the result to `grep`. For example  :
+`zstdcat -D dictionary -qc -- file.zst | grep pattern`
diff --git a/src/zstd/programs/benchfn.c b/src/zstd/programs/benchfn.c
new file mode 100644
index 000000000..ed7273afb
--- /dev/null
+++ b/src/zstd/programs/benchfn.c
@@ -0,0 +1,256 @@
+/*
+ * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
+ */
+
+
+
+/* *************************************
+*  Includes
+***************************************/
+#include <stdlib.h>      /* malloc, free */
+#include <string.h>      /* memset */
+#include <assert.h>      /* assert */
+
+#include "timefn.h"        /* UTIL_time_t, UTIL_getTime */
+#include "benchfn.h"
+
+
+/* *************************************
+*  Constants
+***************************************/
+#define TIMELOOP_MICROSEC     SEC_TO_MICRO      /* 1 second */
+#define TIMELOOP_NANOSEC      (1*1000000000ULL) /* 1 second */
+
+#define KB *(1 <<10)
+#define MB *(1 <<20)
+#define GB *(1U<<30)
+
+
+/* *************************************
+*  Debug errors
+***************************************/
+#if defined(DEBUG) && (DEBUG >= 1)
+#  include <stdio.h>       /* fprintf */
+#  define DISPLAY(...)       fprintf(stderr, __VA_ARGS__)
+#  define DEBUGOUTPUT(...) { if (DEBUG) DISPLAY(__VA_ARGS__); }
+#else
+#  define DEBUGOUTPUT(...)
+#endif
+
+
+/* error without displaying */
+#define RETURN_QUIET_ERROR(retValue, ...) {           \
+    DEBUGOUTPUT("%s: %i: \n", __FILE__, __LINE__);    \
+    DEBUGOUTPUT("Error : ");                          \
+    DEBUGOUTPUT(__VA_ARGS__);                         \
+    DEBUGOUTPUT(" \n");                               \
+    return retValue;                                  \
+}
+
+/* Abort execution if a condition is not met */
+#define CONTROL(c) { if (!(c)) { DEBUGOUTPUT("error: %s \n", #c); abort(); } }
+
+
+/* *************************************
+*  Benchmarking an arbitrary function
+***************************************/
+
+int BMK_isSuccessful_runOutcome(BMK_runOutcome_t outcome)
+{
+    return outcome.error_tag_never_ever_use_directly == 0;
+}
+
+/* warning : this function will stop program execution if outcome is invalid !
+ *           check outcome validity first, using BMK_isValid_runResult() */
+BMK_runTime_t BMK_extract_runTime(BMK_runOutcome_t outcome)
+{
+    CONTROL(outcome.error_tag_never_ever_use_directly == 0);
+    return outcome.internal_never_ever_use_directly;
+}
+
+size_t BMK_extract_errorResult(BMK_runOutcome_t outcome)
+{
+    CONTROL(outcome.error_tag_never_ever_use_directly != 0);
+    return outcome.error_result_never_ever_use_directly;
+}
+
+static BMK_runOutcome_t BMK_runOutcome_error(size_t errorResult)
+{
+    BMK_runOutcome_t b;
+    memset(&b, 0, sizeof(b));
+    b.error_tag_never_ever_use_directly = 1;
+    b.error_result_never_ever_use_directly = errorResult;
+    return b;
+}
+
+static BMK_runOutcome_t BMK_setValid_runTime(BMK_runTime_t runTime)
+{
+    BMK_runOutcome_t outcome;
+    outcome.error_tag_never_ever_use_directly = 0;
+    outcome.internal_never_ever_use_directly = runTime;
+    return outcome;
+}
+
+
+/* initFn will be measured once, benchFn will be measured `nbLoops` times */
+/* initFn is optional, provide NULL if none */
+/* benchFn must return a size_t value that errorFn can interpret */
+/* takes # of blocks and list of size & stuff for each. */
+/* can report result of benchFn for each block into blockResult. */
+/* blockResult is optional, provide NULL if this information is not required */
+/* note : time per loop can be reported as zero if run time < timer resolution */
+BMK_runOutcome_t BMK_benchFunction(BMK_benchParams_t p,
+                                   unsigned nbLoops)
+{
+    size_t dstSize = 0;
+    nbLoops += !nbLoops;   /* minimum nbLoops is 1 */
+
+    /* init */
+    {   size_t i;
+        for(i = 0; i < p.blockCount; i++) {
+            memset(p.dstBuffers[i], 0xE5, p.dstCapacities[i]);  /* warm up and erase result buffer */
+    }   }
+
+    /* benchmark */
+    {   UTIL_time_t const clockStart = UTIL_getTime();
+        unsigned loopNb, blockNb;
+        if (p.initFn != NULL) p.initFn(p.initPayload);
+        for (loopNb = 0; loopNb < nbLoops; loopNb++) {
+            for (blockNb = 0; blockNb < p.blockCount; blockNb++) {
+                size_t const res = p.benchFn(p.srcBuffers[blockNb], p.srcSizes[blockNb],
+                                   p.dstBuffers[blockNb], p.dstCapacities[blockNb],
+                                   p.benchPayload);
+                if (loopNb == 0) {
+                    if (p.blockResults != NULL) p.blockResults[blockNb] = res;
+                    if ((p.errorFn != NULL) && (p.errorFn(res))) {
+                        RETURN_QUIET_ERROR(BMK_runOutcome_error(res),
+                            "Function benchmark failed on block %u (of size %u) with error %i",
+                            blockNb, (unsigned)p.srcSizes[blockNb], (int)res);
+                    }
+                    dstSize += res;
+            }   }
+        }  /* for (loopNb = 0; loopNb < nbLoops; loopNb++) */
+
+        {   PTime const totalTime = UTIL_clockSpanNano(clockStart);
+            BMK_runTime_t rt;
+            rt.nanoSecPerRun = (double)totalTime / nbLoops;
+            rt.sumOfReturn = dstSize;
+            return BMK_setValid_runTime(rt);
+    }   }
+}
+
+
+/* ====  Benchmarking any function, providing intermediate results  ==== */
+
+struct BMK_timedFnState_s {
+    PTime timeSpent_ns;
+    PTime timeBudget_ns;
+    PTime runBudget_ns;
+    BMK_runTime_t fastestRun;
+    unsigned nbLoops;
+    UTIL_time_t coolTime;
+};  /* typedef'd to BMK_timedFnState_t within bench.h */
+
+BMK_timedFnState_t* BMK_createTimedFnState(unsigned total_ms, unsigned run_ms)
+{
+    BMK_timedFnState_t* const r = (BMK_timedFnState_t*)malloc(sizeof(*r));
+    if (r == NULL) return NULL;   /* malloc() error */
+    BMK_resetTimedFnState(r, total_ms, run_ms);
+    return r;
+}
+
+void BMK_freeTimedFnState(BMK_timedFnState_t* state) { free(state); }
+
+BMK_timedFnState_t*
+BMK_initStatic_timedFnState(void* buffer, size_t size, unsigned total_ms, unsigned run_ms)
+{
+    typedef char check_size[ 2 * (sizeof(BMK_timedFnState_shell) >= sizeof(struct BMK_timedFnState_s)) - 1];  /* static assert : a compilation failure indicates that BMK_timedFnState_shell is not large enough */
+    typedef struct { check_size c; BMK_timedFnState_t tfs; } tfs_align;  /* force tfs to be aligned at its next best position */
+    size_t const tfs_alignment = offsetof(tfs_align, tfs); /* provides the minimal alignment restriction for BMK_timedFnState_t */
+    BMK_timedFnState_t* const r = (BMK_timedFnState_t*)buffer;
+    if (buffer == NULL) return NULL;
+    if (size < sizeof(struct BMK_timedFnState_s)) return NULL;
+    if ((size_t)buffer % tfs_alignment) return NULL;  /* buffer must be properly aligned */
+    BMK_resetTimedFnState(r, total_ms, run_ms);
+    return r;
+}
+
+void BMK_resetTimedFnState(BMK_timedFnState_t* timedFnState, unsigned total_ms, unsigned run_ms)
+{
+    if (!total_ms) total_ms = 1 ;
+    if (!run_ms) run_ms = 1;
+    if (run_ms > total_ms) run_ms = total_ms;
+    timedFnState->timeSpent_ns = 0;
+    timedFnState->timeBudget_ns = (PTime)total_ms * TIMELOOP_NANOSEC / 1000;
+    timedFnState->runBudget_ns = (PTime)run_ms * TIMELOOP_NANOSEC / 1000;
+    timedFnState->fastestRun.nanoSecPerRun = (double)TIMELOOP_NANOSEC * 2000000000;  /* hopefully large enough : must be larger than any potential measurement */
+    timedFnState->fastestRun.sumOfReturn = (size_t)(-1LL);
+    timedFnState->nbLoops = 1;
+    timedFnState->coolTime = UTIL_getTime();
+}
+
+/* Tells if nb of seconds set in timedFnState for all runs is spent.
+ * note : this function will return 1 if BMK_benchFunctionTimed() has actually errored. */
+int BMK_isCompleted_TimedFn(const BMK_timedFnState_t* timedFnState)
+{
+    return (timedFnState->timeSpent_ns >= timedFnState->timeBudget_ns);
+}
+
+
+#undef MIN
+#define MIN(a,b)   ( (a) < (b) ? (a) : (b) )
+
+#define MINUSABLETIME  (TIMELOOP_NANOSEC / 2)  /* 0.5 seconds */
+
+BMK_runOutcome_t BMK_benchTimedFn(BMK_timedFnState_t* cont,
+                                  BMK_benchParams_t p)
+{
+    PTime const runBudget_ns = cont->runBudget_ns;
+    PTime const runTimeMin_ns = runBudget_ns / 2;
+    int completed = 0;
+    BMK_runTime_t bestRunTime = cont->fastestRun;
+
+    while (!completed) {
+        BMK_runOutcome_t const runResult = BMK_benchFunction(p, cont->nbLoops);
+
+        if(!BMK_isSuccessful_runOutcome(runResult)) { /* error : move out */
+            return runResult;
+        }
+
+        {   BMK_runTime_t const newRunTime = BMK_extract_runTime(runResult);
+            double const loopDuration_ns = newRunTime.nanoSecPerRun * cont->nbLoops;
+
+            cont->timeSpent_ns += (unsigned long long)loopDuration_ns;
+
+            /* estimate nbLoops for next run to last approximately 1 second */
+            if (loopDuration_ns > (runBudget_ns / 50)) {
+                double const fastestRun_ns = MIN(bestRunTime.nanoSecPerRun, newRunTime.nanoSecPerRun);
+                cont->nbLoops = (unsigned)(runBudget_ns / fastestRun_ns) + 1;
+            } else {
+                /* previous run was too short : blindly increase workload by x multiplier */
+                const unsigned multiplier = 10;
+                assert(cont->nbLoops < ((unsigned)-1) / multiplier);  /* avoid overflow */
+                cont->nbLoops *= multiplier;
+            }
+
+            if(loopDuration_ns < runTimeMin_ns) {
+                /* don't report results for which benchmark run time was too small : increased risks of rounding errors */
+                assert(completed == 0);
+                continue;
+            } else {
+                if(newRunTime.nanoSecPerRun < bestRunTime.nanoSecPerRun) {
+                    bestRunTime = newRunTime;
+                }
+                completed = 1;
+            }
+        }
+    }   /* while (!completed) */
+
+    return BMK_setValid_runTime(bestRunTime);
+}
diff --git a/src/zstd/programs/benchfn.h b/src/zstd/programs/benchfn.h
new file mode 100644
index 000000000..e555bbe6a
--- /dev/null
+++ b/src/zstd/programs/benchfn.h
@@ -0,0 +1,183 @@
+/*
+ * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
+ */
+
+
+/* benchfn :
+ * benchmark any function on a set of input
+ * providing result in nanoSecPerRun
+ * or detecting and returning an error
+ */
+
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
+#ifndef BENCH_FN_H_23876
+#define BENCH_FN_H_23876
+
+/* ===  Dependencies  === */
+#include <stddef.h>   /* size_t */
+
+
+/* ====  Benchmark any function, iterated on a set of blocks  ==== */
+
+/* BMK_runTime_t: valid result return type */
+
+typedef struct {
+    double nanoSecPerRun;  /* time per iteration (over all blocks) */
+    size_t sumOfReturn;         /* sum of return values */
+} BMK_runTime_t;
+
+
+/* BMK_runOutcome_t:
+ * type expressing the outcome of a benchmark run by BMK_benchFunction(),
+ * which can be either valid or invalid.
+ * benchmark outcome can be invalid if errorFn is provided.
+ * BMK_runOutcome_t must be considered "opaque" : never access its members directly.
+ * Instead, use its assigned methods :
+ * BMK_isSuccessful_runOutcome, BMK_extract_runTime, BMK_extract_errorResult.
+ * The structure is only described here to allow its allocation on stack. */
+
+typedef struct {
+    BMK_runTime_t internal_never_ever_use_directly;
+    size_t error_result_never_ever_use_directly;
+    int error_tag_never_ever_use_directly;
+} BMK_runOutcome_t;
+
+
+/* prototypes for benchmarked functions */
+typedef size_t (*BMK_benchFn_t)(const void* src, size_t srcSize, void* dst, size_t dstCapacity, void* customPayload);
+typedef size_t (*BMK_initFn_t)(void* initPayload);
+typedef unsigned (*BMK_errorFn_t)(size_t);
+
+
+/* BMK_benchFunction() parameters are provided via the following structure.
+ * A structure is preferable for readability,
+ * as the number of parameters required is fairly large.
+ * No initializer is provided, because it doesn't make sense to provide some "default" :
+ * all parameters must be specified by the caller.
+ * optional parameters are labelled explicitly, and accept value NULL when not used */
+typedef struct {
+    BMK_benchFn_t benchFn;    /* the function to benchmark, over the set of blocks */
+    void* benchPayload;       /* pass custom parameters to benchFn  :
+                               * (*benchFn)(srcBuffers[i], srcSizes[i], dstBuffers[i], dstCapacities[i], benchPayload) */
+    BMK_initFn_t initFn;      /* (*initFn)(initPayload) is run once per run, at the beginning. */
+    void* initPayload;        /* Both arguments can be NULL, in which case nothing is run. */
+    BMK_errorFn_t errorFn;    /* errorFn will check each return value of benchFn over each block, to determine if it failed or not.
+                               * errorFn can be NULL, in which case no check is performed.
+                               * errorFn must return 0 when benchFn was successful, and >= 1 if it detects an error.
+                               * Execution is stopped as soon as an error is detected.
+                               * the triggering return value can be retrieved using BMK_extract_errorResult(). */
+    size_t blockCount;        /* number of blocks to operate benchFn on.
+                               * It's also the size of all array parameters :
+                               * srcBuffers, srcSizes, dstBuffers, dstCapacities, blockResults */
+    const void *const * srcBuffers; /* read-only array of buffers to be operated on by benchFn */
+    const size_t* srcSizes;   /* read-only array containing sizes of srcBuffers */
+    void *const * dstBuffers; /* array of buffers to be written into by benchFn. This array is not optional, it must be provided even if unused by benchfn. */
+    const size_t* dstCapacities; /* read-only array containing capacities of dstBuffers. This array must be present. */
+    size_t* blockResults;     /* Optional: store the return value of benchFn for each block. Use NULL if this result is not requested. */
+} BMK_benchParams_t;
+
+
+/* BMK_benchFunction() :
+ * This function benchmarks benchFn and initFn, providing a result.
+ *
+ * params : see description of BMK_benchParams_t above.
+ * nbLoops: defines number of times benchFn is run over the full set of blocks.
+ *          Minimum value is 1. A 0 is interpreted as a 1.
+ *
+ * @return: can express either an error or a successful result.
+ *          Use BMK_isSuccessful_runOutcome() to check if benchmark was successful.
+ *          If yes, extract the result with BMK_extract_runTime(),
+ *          it will contain :
+ *              .sumOfReturn : the sum of all return values of benchFn through all of blocks
+ *              .nanoSecPerRun : time per run of benchFn + (time for initFn / nbLoops)
+ *          .sumOfReturn is generally intended for functions which return a # of bytes written into dstBuffer,
+ *              in which case, this value will be the total amount of bytes written into dstBuffer.
+ *
+ * blockResults : when provided (!= NULL), and when benchmark is successful,
+ *                params.blockResults contains all return values of `benchFn` over all blocks.
+ *                when provided (!= NULL), and when benchmark failed,
+ *                params.blockResults contains return values of `benchFn` over all blocks preceding and including the failed block.
+ */
+BMK_runOutcome_t BMK_benchFunction(BMK_benchParams_t params, unsigned nbLoops);
+
+
+
+/* check first if the benchmark was successful or not */
+int BMK_isSuccessful_runOutcome(BMK_runOutcome_t outcome);
+
+/* If the benchmark was successful, extract the result.
+ * note : this function will abort() program execution if benchmark failed !
+ *        always check if benchmark was successful first !
+ */
+BMK_runTime_t BMK_extract_runTime(BMK_runOutcome_t outcome);
+
+/* when benchmark failed, it means one invocation of `benchFn` failed.
+ * The failure was detected by `errorFn`, operating on return values of `benchFn`.
+ * Returns the faulty return value.
+ * note : this function will abort() program execution if benchmark did not failed.
+ *        always check if benchmark failed first !
+ */
+size_t BMK_extract_errorResult(BMK_runOutcome_t outcome);
+
+
+
+/* ====  Benchmark any function, returning intermediate results  ==== */
+
+/* state information tracking benchmark session */
+typedef struct BMK_timedFnState_s BMK_timedFnState_t;
+
+/* BMK_benchTimedFn() :
+ * Similar to BMK_benchFunction(), most arguments being identical.
+ * Automatically determines `nbLoops` so that each result is regularly produced at interval of about run_ms.
+ * Note : minimum `nbLoops` is 1, therefore a run may last more than run_ms, and possibly even more than total_ms.
+ * Usage - initialize timedFnState, select benchmark duration (total_ms) and each measurement duration (run_ms)
+ *         call BMK_benchTimedFn() repetitively, each measurement is supposed to last about run_ms
+ *         Check if total time budget is spent or exceeded, using BMK_isCompleted_TimedFn()
+ */
+BMK_runOutcome_t BMK_benchTimedFn(BMK_timedFnState_t* timedFnState,
+                                  BMK_benchParams_t params);
+
+/* Tells if duration of all benchmark runs has exceeded total_ms
+ */
+int BMK_isCompleted_TimedFn(const BMK_timedFnState_t* timedFnState);
+
+/* BMK_createTimedFnState() and BMK_resetTimedFnState() :
+ * Create/Set BMK_timedFnState_t for next benchmark session,
+ * which shall last a minimum of total_ms milliseconds,
+ * producing intermediate results, paced at interval of (approximately) run_ms.
+ */
+BMK_timedFnState_t* BMK_createTimedFnState(unsigned total_ms, unsigned run_ms);
+void BMK_resetTimedFnState(BMK_timedFnState_t* timedFnState, unsigned total_ms, unsigned run_ms);
+void BMK_freeTimedFnState(BMK_timedFnState_t* state);
+
+
+/* BMK_timedFnState_shell and BMK_initStatic_timedFnState() :
+ * Makes it possible to statically allocate a BMK_timedFnState_t on stack.
+ * BMK_timedFnState_shell is only there to allocate space,
+ * never ever access its members.
+ * BMK_timedFnState_t() actually accepts any buffer.
+ * It will check if provided buffer is large enough and is correctly aligned,
+ * and will return NULL if conditions are not respected.
+ */
+#define BMK_TIMEDFNSTATE_SIZE 64
+typedef union {
+    char never_access_space[BMK_TIMEDFNSTATE_SIZE];
+    long long alignment_enforcer;  /* must be aligned on 8-bytes boundaries */
+} BMK_timedFnState_shell;
+BMK_timedFnState_t* BMK_initStatic_timedFnState(void* buffer, size_t size, unsigned total_ms, unsigned run_ms);
+
+
+#endif   /* BENCH_FN_H_23876 */
+
+#if defined (__cplusplus)
+}
+#endif
diff --git a/src/zstd/programs/benchzstd.c b/src/zstd/programs/benchzstd.c
new file mode 100644
index 000000000..77056203d
--- /dev/null
+++ b/src/zstd/programs/benchzstd.c
@@ -0,0 +1,888 @@
+/*
+ * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
+ */
+
+
+/* **************************************
+*  Tuning parameters
+****************************************/
+#ifndef BMK_TIMETEST_DEFAULT_S   /* default minimum time per test */
+#define BMK_TIMETEST_DEFAULT_S 3
+#endif
+
+
+/* *************************************
+*  Includes
+***************************************/
+#include "platform.h"    /* Large Files support */
+#include "util.h"        /* UTIL_getFileSize, UTIL_sleep */
+#include <stdlib.h>      /* malloc, free */
+#include <string.h>      /* memset, strerror */
+#include <stdio.h>       /* fprintf, fopen */
+#include <errno.h>
+#include <assert.h>      /* assert */
+
+#include "timefn.h"      /* UTIL_time_t */
+#include "benchfn.h"
+#include "../lib/common/mem.h"
+#define ZSTD_STATIC_LINKING_ONLY
+#include "../lib/zstd.h"
+#include "datagen.h"     /* RDG_genBuffer */
+#include "../lib/common/xxhash.h"
+#include "benchzstd.h"
+#include "../lib/common/zstd_errors.h"
+
+
+/* *************************************
+*  Constants
+***************************************/
+#ifndef ZSTD_GIT_COMMIT
+#  define ZSTD_GIT_COMMIT_STRING ""
+#else
+#  define ZSTD_GIT_COMMIT_STRING ZSTD_EXPAND_AND_QUOTE(ZSTD_GIT_COMMIT)
+#endif
+
+#define TIMELOOP_MICROSEC     (1*1000000ULL) /* 1 second */
+#define TIMELOOP_NANOSEC      (1*1000000000ULL) /* 1 second */
+#define ACTIVEPERIOD_MICROSEC (70*TIMELOOP_MICROSEC) /* 70 seconds */
+#define COOLPERIOD_SEC        10
+
+#define KB *(1 <<10)
+#define MB *(1 <<20)
+#define GB *(1U<<30)
+
+#define BMK_RUNTEST_DEFAULT_MS 1000
+
+static const size_t maxMemory = (sizeof(size_t)==4)  ?
+                    /* 32-bit */ (2 GB - 64 MB) :
+                    /* 64-bit */ (size_t)(1ULL << ((sizeof(size_t)*8)-31));
+
+
+/* *************************************
+*  console display
+***************************************/
+#define DISPLAY(...)         fprintf(stderr, __VA_ARGS__)
+#define DISPLAYLEVEL(l, ...) if (displayLevel>=l) { DISPLAY(__VA_ARGS__); }
+/* 0 : no display;   1: errors;   2 : + result + interaction + warnings;   3 : + progression;   4 : + information */
+
+static const U64 g_refreshRate = SEC_TO_MICRO / 6;
+static UTIL_time_t g_displayClock = UTIL_TIME_INITIALIZER;
+
+#define DISPLAYUPDATE(l, ...) { if (displayLevel>=l) { \
+            if ((UTIL_clockSpanMicro(g_displayClock) > g_refreshRate) || (displayLevel>=4)) \
+            { g_displayClock = UTIL_getTime(); DISPLAY(__VA_ARGS__); \
+            if (displayLevel>=4) fflush(stderr); } } }
+
+
+/* *************************************
+*  Exceptions
+***************************************/
+#ifndef DEBUG
+#  define DEBUG 0
+#endif
+#define DEBUGOUTPUT(...) { if (DEBUG) DISPLAY(__VA_ARGS__); }
+
+#define RETURN_ERROR_INT(errorNum, ...)  {               \
+    DEBUGOUTPUT("%s: %i: \n", __FILE__, __LINE__);    \
+    DISPLAYLEVEL(1, "Error %i : ", errorNum);         \
+    DISPLAYLEVEL(1, __VA_ARGS__);                     \
+    DISPLAYLEVEL(1, " \n");                           \
+    return errorNum;                                  \
+}
+
+#define CHECK_Z(zf) {              \
+    size_t const zerr = zf;        \
+    if (ZSTD_isError(zerr)) {      \
+        DEBUGOUTPUT("%s: %i: \n", __FILE__, __LINE__);  \
+        DISPLAY("Error : ");       \
+        DISPLAY("%s failed : %s",  \
+                #zf, ZSTD_getErrorName(zerr));   \
+        DISPLAY(" \n");            \
+        exit(1);                   \
+    }                              \
+}
+
+#define RETURN_ERROR(errorNum, retType, ...)  {       \
+    retType r;                                        \
+    memset(&r, 0, sizeof(retType));                   \
+    DEBUGOUTPUT("%s: %i: \n", __FILE__, __LINE__);    \
+    DISPLAYLEVEL(1, "Error %i : ", errorNum);         \
+    DISPLAYLEVEL(1, __VA_ARGS__);                     \
+    DISPLAYLEVEL(1, " \n");                           \
+    r.tag = errorNum;                                 \
+    return r;                                         \
+}
+
+
+/* *************************************
+*  Benchmark Parameters
+***************************************/
+
+BMK_advancedParams_t BMK_initAdvancedParams(void) {
+    BMK_advancedParams_t const res = {
+        BMK_both, /* mode */
+        BMK_TIMETEST_DEFAULT_S, /* nbSeconds */
+        0, /* blockSize */
+        0, /* nbWorkers */
+        0, /* realTime */
+        0, /* additionalParam */
+        0, /* ldmFlag */
+        0, /* ldmMinMatch */
+        0, /* ldmHashLog */
+        0, /* ldmBuckSizeLog */
+        0,  /* ldmHashRateLog */
+        ZSTD_lcm_auto /* literalCompressionMode */
+    };
+    return res;
+}
+
+
+/* ********************************************************
+*  Bench functions
+**********************************************************/
+typedef struct {
+    const void* srcPtr;
+    size_t srcSize;
+    void*  cPtr;
+    size_t cRoom;
+    size_t cSize;
+    void*  resPtr;
+    size_t resSize;
+} blockParam_t;
+
+#undef MIN
+#undef MAX
+#define MIN(a,b)    ((a) < (b) ? (a) : (b))
+#define MAX(a,b)    ((a) > (b) ? (a) : (b))
+
+static void
+BMK_initCCtx(ZSTD_CCtx* ctx,
+            const void* dictBuffer, size_t dictBufferSize,
+            int cLevel,
+            const ZSTD_compressionParameters* comprParams,
+            const BMK_advancedParams_t* adv)
+{
+    ZSTD_CCtx_reset(ctx, ZSTD_reset_session_and_parameters);
+    if (adv->nbWorkers==1) {
+        CHECK_Z(ZSTD_CCtx_setParameter(ctx, ZSTD_c_nbWorkers, 0));
+    } else {
+        CHECK_Z(ZSTD_CCtx_setParameter(ctx, ZSTD_c_nbWorkers, adv->nbWorkers));
+    }
+    CHECK_Z(ZSTD_CCtx_setParameter(ctx, ZSTD_c_compressionLevel, cLevel));
+    CHECK_Z(ZSTD_CCtx_setParameter(ctx, ZSTD_c_enableLongDistanceMatching, adv->ldmFlag));
+    CHECK_Z(ZSTD_CCtx_setParameter(ctx, ZSTD_c_ldmMinMatch, adv->ldmMinMatch));
+    CHECK_Z(ZSTD_CCtx_setParameter(ctx, ZSTD_c_ldmHashLog, adv->ldmHashLog));
+    CHECK_Z(ZSTD_CCtx_setParameter(ctx, ZSTD_c_ldmBucketSizeLog, adv->ldmBucketSizeLog));
+    CHECK_Z(ZSTD_CCtx_setParameter(ctx, ZSTD_c_ldmHashRateLog, adv->ldmHashRateLog));
+    CHECK_Z(ZSTD_CCtx_setParameter(ctx, ZSTD_c_windowLog, (int)comprParams->windowLog));
+    CHECK_Z(ZSTD_CCtx_setParameter(ctx, ZSTD_c_hashLog, (int)comprParams->hashLog));
+    CHECK_Z(ZSTD_CCtx_setParameter(ctx, ZSTD_c_chainLog, (int)comprParams->chainLog));
+    CHECK_Z(ZSTD_CCtx_setParameter(ctx, ZSTD_c_searchLog, (int)comprParams->searchLog));
+    CHECK_Z(ZSTD_CCtx_setParameter(ctx, ZSTD_c_minMatch, (int)comprParams->minMatch));
+    CHECK_Z(ZSTD_CCtx_setParameter(ctx, ZSTD_c_targetLength, (int)comprParams->targetLength));
+    CHECK_Z(ZSTD_CCtx_setParameter(ctx, ZSTD_c_literalCompressionMode, (int)adv->literalCompressionMode));
+    CHECK_Z(ZSTD_CCtx_setParameter(ctx, ZSTD_c_strategy, comprParams->strategy));
+    CHECK_Z(ZSTD_CCtx_loadDictionary(ctx, dictBuffer, dictBufferSize));
+}
+
+static void BMK_initDCtx(ZSTD_DCtx* dctx,
+    const void* dictBuffer, size_t dictBufferSize) {
+    CHECK_Z(ZSTD_DCtx_reset(dctx, ZSTD_reset_session_and_parameters));
+    CHECK_Z(ZSTD_DCtx_loadDictionary(dctx, dictBuffer, dictBufferSize));
+}
+
+
+typedef struct {
+    ZSTD_CCtx* cctx;
+    const void* dictBuffer;
+    size_t dictBufferSize;
+    int cLevel;
+    const ZSTD_compressionParameters* comprParams;
+    const BMK_advancedParams_t* adv;
+} BMK_initCCtxArgs;
+
+static size_t local_initCCtx(void* payload) {
+    BMK_initCCtxArgs* ag = (BMK_initCCtxArgs*)payload;
+    BMK_initCCtx(ag->cctx, ag->dictBuffer, ag->dictBufferSize, ag->cLevel, ag->comprParams, ag->adv);
+    return 0;
+}
+
+typedef struct {
+    ZSTD_DCtx* dctx;
+    const void* dictBuffer;
+    size_t dictBufferSize;
+} BMK_initDCtxArgs;
+
+static size_t local_initDCtx(void* payload) {
+    BMK_initDCtxArgs* ag = (BMK_initDCtxArgs*)payload;
+    BMK_initDCtx(ag->dctx, ag->dictBuffer, ag->dictBufferSize);
+    return 0;
+}
+
+
+/* `addArgs` is the context */
+static size_t local_defaultCompress(
+                    const void* srcBuffer, size_t srcSize,
+                    void* dstBuffer, size_t dstSize,
+                    void* addArgs)
+{
+    ZSTD_CCtx* const cctx = (ZSTD_CCtx*)addArgs;
+    return ZSTD_compress2(cctx, dstBuffer, dstSize, srcBuffer, srcSize);
+}
+
+/* `addArgs` is the context */
+static size_t local_defaultDecompress(
+                    const void* srcBuffer, size_t srcSize,
+                    void* dstBuffer, size_t dstCapacity,
+                    void* addArgs)
+{
+    size_t moreToFlush = 1;
+    ZSTD_DCtx* const dctx = (ZSTD_DCtx*)addArgs;
+    ZSTD_inBuffer in;
+    ZSTD_outBuffer out;
+    in.src = srcBuffer; in.size = srcSize; in.pos = 0;
+    out.dst = dstBuffer; out.size = dstCapacity; out.pos = 0;
+    while (moreToFlush) {
+        if(out.pos == out.size) {
+            return (size_t)-ZSTD_error_dstSize_tooSmall;
+        }
+        moreToFlush = ZSTD_decompressStream(dctx, &out, &in);
+        if (ZSTD_isError(moreToFlush)) {
+            return moreToFlush;
+        }
+    }
+    return out.pos;
+
+}
+
+
+/* ================================================================= */
+/*      Benchmark Zstandard, mem-to-mem scenarios                    */
+/* ================================================================= */
+
+int BMK_isSuccessful_benchOutcome(BMK_benchOutcome_t outcome)
+{
+    return outcome.tag == 0;
+}
+
+BMK_benchResult_t BMK_extract_benchResult(BMK_benchOutcome_t outcome)
+{
+    assert(outcome.tag == 0);
+    return outcome.internal_never_use_directly;
+}
+
+static BMK_benchOutcome_t BMK_benchOutcome_error(void)
+{
+    BMK_benchOutcome_t b;
+    memset(&b, 0, sizeof(b));
+    b.tag = 1;
+    return b;
+}
+
+static BMK_benchOutcome_t BMK_benchOutcome_setValidResult(BMK_benchResult_t result)
+{
+    BMK_benchOutcome_t b;
+    b.tag = 0;
+    b.internal_never_use_directly = result;
+    return b;
+}
+
+
+/* benchMem with no allocation */
+static BMK_benchOutcome_t
+BMK_benchMemAdvancedNoAlloc(
+                    const void** srcPtrs, size_t* srcSizes,
+                    void** cPtrs, size_t* cCapacities, size_t* cSizes,
+                    void** resPtrs, size_t* resSizes,
+                    void** resultBufferPtr, void* compressedBuffer,
+                    size_t maxCompressedSize,
+                    BMK_timedFnState_t* timeStateCompress,
+                    BMK_timedFnState_t* timeStateDecompress,
+
+                    const void* srcBuffer, size_t srcSize,
+                    const size_t* fileSizes, unsigned nbFiles,
+                    const int cLevel,
+                    const ZSTD_compressionParameters* comprParams,
+                    const void* dictBuffer, size_t dictBufferSize,
+                    ZSTD_CCtx* cctx, ZSTD_DCtx* dctx,
+                    int displayLevel, const char* displayName,
+                    const BMK_advancedParams_t* adv)
+{
+    size_t const blockSize = ((adv->blockSize>=32 && (adv->mode != BMK_decodeOnly)) ? adv->blockSize : srcSize) + (!srcSize);  /* avoid div by 0 */
+    BMK_benchResult_t benchResult;
+    size_t const loadedCompressedSize = srcSize;
+    size_t cSize = 0;
+    double ratio = 0.;
+    U32 nbBlocks;
+
+    assert(cctx != NULL); assert(dctx != NULL);
+
+    /* init */
+    memset(&benchResult, 0, sizeof(benchResult));
+    if (strlen(displayName)>17) displayName += strlen(displayName) - 17;   /* display last 17 characters */
+    if (adv->mode == BMK_decodeOnly) {  /* benchmark only decompression : source must be already compressed */
+        const char* srcPtr = (const char*)srcBuffer;
+        U64 totalDSize64 = 0;
+        U32 fileNb;
+        for (fileNb=0; fileNb<nbFiles; fileNb++) {
+            U64 const fSize64 = ZSTD_findDecompressedSize(srcPtr, fileSizes[fileNb]);
+            if (fSize64==0) RETURN_ERROR(32, BMK_benchOutcome_t, "Impossible to determine original size ");
+            totalDSize64 += fSize64;
+            srcPtr += fileSizes[fileNb];
+        }
+        {   size_t const decodedSize = (size_t)totalDSize64;
+            assert((U64)decodedSize == totalDSize64);   /* check overflow */
+            free(*resultBufferPtr);
+            *resultBufferPtr = malloc(decodedSize);
+            if (!(*resultBufferPtr)) {
+                RETURN_ERROR(33, BMK_benchOutcome_t, "not enough memory");
+            }
+            if (totalDSize64 > decodedSize) {  /* size_t overflow */
+                free(*resultBufferPtr);
+                RETURN_ERROR(32, BMK_benchOutcome_t, "original size is too large");
+            }
+            cSize = srcSize;
+            srcSize = decodedSize;
+            ratio = (double)srcSize / (double)cSize;
+        }
+    }
+
+    /* Init data blocks  */
+    {   const char* srcPtr = (const char*)srcBuffer;
+        char* cPtr = (char*)compressedBuffer;
+        char* resPtr = (char*)(*resultBufferPtr);
+        U32 fileNb;
+        for (nbBlocks=0, fileNb=0; fileNb<nbFiles; fileNb++) {
+            size_t remaining = fileSizes[fileNb];
+            U32 const nbBlocksforThisFile = (adv->mode == BMK_decodeOnly) ? 1 : (U32)((remaining + (blockSize-1)) / blockSize);
+            U32 const blockEnd = nbBlocks + nbBlocksforThisFile;
+            for ( ; nbBlocks<blockEnd; nbBlocks++) {
+                size_t const thisBlockSize = MIN(remaining, blockSize);
+                srcPtrs[nbBlocks] = srcPtr;
+                srcSizes[nbBlocks] = thisBlockSize;
+                cPtrs[nbBlocks] = cPtr;
+                cCapacities[nbBlocks] = (adv->mode == BMK_decodeOnly) ? thisBlockSize : ZSTD_compressBound(thisBlockSize);
+                resPtrs[nbBlocks] = resPtr;
+                resSizes[nbBlocks] = (adv->mode == BMK_decodeOnly) ? (size_t) ZSTD_findDecompressedSize(srcPtr, thisBlockSize) : thisBlockSize;
+                srcPtr += thisBlockSize;
+                cPtr += cCapacities[nbBlocks];
+                resPtr += thisBlockSize;
+                remaining -= thisBlockSize;
+                if (adv->mode == BMK_decodeOnly) {
+                    cSizes[nbBlocks] = thisBlockSize;
+                    benchResult.cSize = thisBlockSize;
+                }
+            }
+        }
+    }
+
+    /* warming up `compressedBuffer` */
+    if (adv->mode == BMK_decodeOnly) {
+        memcpy(compressedBuffer, srcBuffer, loadedCompressedSize);
+    } else {
+        RDG_genBuffer(compressedBuffer, maxCompressedSize, 0.10, 0.50, 1);
+    }
+
+    /* Bench */
+    {   U64 const crcOrig = (adv->mode == BMK_decodeOnly) ? 0 : XXH64(srcBuffer, srcSize, 0);
+#       define NB_MARKS 4
+        const char* marks[NB_MARKS] = { " |", " /", " =", " \\" };
+        U32 markNb = 0;
+        int compressionCompleted = (adv->mode == BMK_decodeOnly);
+        int decompressionCompleted = (adv->mode == BMK_compressOnly);
+        BMK_benchParams_t cbp, dbp;
+        BMK_initCCtxArgs cctxprep;
+        BMK_initDCtxArgs dctxprep;
+
+        cbp.benchFn = local_defaultCompress;   /* ZSTD_compress2 */
+        cbp.benchPayload = cctx;
+        cbp.initFn = local_initCCtx;   /* BMK_initCCtx */
+        cbp.initPayload = &cctxprep;
+        cbp.errorFn = ZSTD_isError;
+        cbp.blockCount = nbBlocks;
+        cbp.srcBuffers = srcPtrs;
+        cbp.srcSizes = srcSizes;
+        cbp.dstBuffers = cPtrs;
+        cbp.dstCapacities = cCapacities;
+        cbp.blockResults = cSizes;
+
+        cctxprep.cctx = cctx;
+        cctxprep.dictBuffer = dictBuffer;
+        cctxprep.dictBufferSize = dictBufferSize;
+        cctxprep.cLevel = cLevel;
+        cctxprep.comprParams = comprParams;
+        cctxprep.adv = adv;
+
+        dbp.benchFn = local_defaultDecompress;
+        dbp.benchPayload = dctx;
+        dbp.initFn = local_initDCtx;
+        dbp.initPayload = &dctxprep;
+        dbp.errorFn = ZSTD_isError;
+        dbp.blockCount = nbBlocks;
+        dbp.srcBuffers = (const void* const *) cPtrs;
+        dbp.srcSizes = cSizes;
+        dbp.dstBuffers = resPtrs;
+        dbp.dstCapacities = resSizes;
+        dbp.blockResults = NULL;
+
+        dctxprep.dctx = dctx;
+        dctxprep.dictBuffer = dictBuffer;
+        dctxprep.dictBufferSize = dictBufferSize;
+
+        DISPLAYLEVEL(2, "\r%70s\r", "");   /* blank line */
+        DISPLAYLEVEL(2, "%2s-%-17.17s :%10u ->\r", marks[markNb], displayName, (unsigned)srcSize);
+
+        while (!(compressionCompleted && decompressionCompleted)) {
+            if (!compressionCompleted) {
+                BMK_runOutcome_t const cOutcome = BMK_benchTimedFn( timeStateCompress, cbp);
+
+                if (!BMK_isSuccessful_runOutcome(cOutcome)) {
+                    return BMK_benchOutcome_error();
+                }
+
+                {   BMK_runTime_t const cResult = BMK_extract_runTime(cOutcome);
+                    cSize = cResult.sumOfReturn;
+                    ratio = (double)srcSize / cSize;
+                    {   BMK_benchResult_t newResult;
+                        newResult.cSpeed = (U64)((double)srcSize * TIMELOOP_NANOSEC / cResult.nanoSecPerRun);
+                        benchResult.cSize = cSize;
+                        if (newResult.cSpeed > benchResult.cSpeed)
+                            benchResult.cSpeed = newResult.cSpeed;
+                }   }
+
+                {   int const ratioAccuracy = (ratio < 10.) ? 3 : 2;
+                    DISPLAYLEVEL(2, "%2s-%-17.17s :%10u ->%10u (%5.*f),%6.*f MB/s\r",
+                            marks[markNb], displayName,
+                            (unsigned)srcSize, (unsigned)cSize,
+                            ratioAccuracy, ratio,
+                            benchResult.cSpeed < (10 MB) ? 2 : 1, (double)benchResult.cSpeed / MB_UNIT);
+                }
+                compressionCompleted = BMK_isCompleted_TimedFn(timeStateCompress);
+            }
+
+            if(!decompressionCompleted) {
+                BMK_runOutcome_t const dOutcome = BMK_benchTimedFn(timeStateDecompress, dbp);
+
+                if(!BMK_isSuccessful_runOutcome(dOutcome)) {
+                    return BMK_benchOutcome_error();
+                }
+
+                {   BMK_runTime_t const dResult = BMK_extract_runTime(dOutcome);
+                    U64 const newDSpeed = (U64)((double)srcSize * TIMELOOP_NANOSEC / dResult.nanoSecPerRun);
+                    if (newDSpeed > benchResult.dSpeed)
+                        benchResult.dSpeed = newDSpeed;
+                }
+
+                {   int const ratioAccuracy = (ratio < 10.) ? 3 : 2;
+                    DISPLAYLEVEL(2, "%2s-%-17.17s :%10u ->%10u (%5.*f),%6.*f MB/s ,%6.1f MB/s \r",
+                            marks[markNb], displayName,
+                            (unsigned)srcSize, (unsigned)cSize,
+                            ratioAccuracy, ratio,
+                            benchResult.cSpeed < (10 MB) ? 2 : 1, (double)benchResult.cSpeed / MB_UNIT,
+                            (double)benchResult.dSpeed / MB_UNIT);
+                }
+                decompressionCompleted = BMK_isCompleted_TimedFn(timeStateDecompress);
+            }
+            markNb = (markNb+1) % NB_MARKS;
+        }   /* while (!(compressionCompleted && decompressionCompleted)) */
+
+        /* CRC Checking */
+        {   const BYTE* resultBuffer = (const BYTE*)(*resultBufferPtr);
+            U64 const crcCheck = XXH64(resultBuffer, srcSize, 0);
+            if ((adv->mode == BMK_both) && (crcOrig!=crcCheck)) {
+                size_t u;
+                DISPLAY("!!! WARNING !!! %14s : Invalid Checksum : %x != %x   \n",
+                        displayName, (unsigned)crcOrig, (unsigned)crcCheck);
+                for (u=0; u<srcSize; u++) {
+                    if (((const BYTE*)srcBuffer)[u] != resultBuffer[u]) {
+                        unsigned segNb, bNb, pos;
+                        size_t bacc = 0;
+                        DISPLAY("Decoding error at pos %u ", (unsigned)u);
+                        for (segNb = 0; segNb < nbBlocks; segNb++) {
+                            if (bacc + srcSizes[segNb] > u) break;
+                            bacc += srcSizes[segNb];
+                        }
+                        pos = (U32)(u - bacc);
+                        bNb = pos / (128 KB);
+                        DISPLAY("(sample %u, block %u, pos %u) \n", segNb, bNb, pos);
+                        {   size_t const lowest = (u>5) ? 5 : u;
+                            size_t n;
+                            DISPLAY("origin: ");
+                            for (n=lowest; n>0; n--)
+                                DISPLAY("%02X ", ((const BYTE*)srcBuffer)[u-n]);
+                            DISPLAY(" :%02X:  ", ((const BYTE*)srcBuffer)[u]);
+                            for (n=1; n<3; n++)
+                                DISPLAY("%02X ", ((const BYTE*)srcBuffer)[u+n]);
+                            DISPLAY(" \n");
+                            DISPLAY("decode: ");
+                            for (n=lowest; n>0; n++)
+                                DISPLAY("%02X ", resultBuffer[u-n]);
+                            DISPLAY(" :%02X:  ", resultBuffer[u]);
+                            for (n=1; n<3; n++)
+                                DISPLAY("%02X ", resultBuffer[u+n]);
+                            DISPLAY(" \n");
+                        }
+                        break;
+                    }
+                    if (u==srcSize-1) {  /* should never happen */
+                        DISPLAY("no difference detected\n");
+                    }
+                }   /* for (u=0; u<srcSize; u++) */
+            }   /* if ((adv->mode == BMK_both) && (crcOrig!=crcCheck)) */
+        }   /* CRC Checking */
+
+        if (displayLevel == 1) {   /* hidden display mode -q, used by python speed benchmark */
+            double const cSpeed = (double)benchResult.cSpeed / MB_UNIT;
+            double const dSpeed = (double)benchResult.dSpeed / MB_UNIT;
+            if (adv->additionalParam) {
+                DISPLAY("-%-3i%11i (%5.3f) %6.2f MB/s %6.1f MB/s  %s (param=%d)\n", cLevel, (int)cSize, ratio, cSpeed, dSpeed, displayName, adv->additionalParam);
+            } else {
+                DISPLAY("-%-3i%11i (%5.3f) %6.2f MB/s %6.1f MB/s  %s\n", cLevel, (int)cSize, ratio, cSpeed, dSpeed, displayName);
+            }
+        }
+
+        DISPLAYLEVEL(2, "%2i#\n", cLevel);
+    }   /* Bench */
+
+    benchResult.cMem = (1ULL << (comprParams->windowLog)) + ZSTD_sizeof_CCtx(cctx);
+    return BMK_benchOutcome_setValidResult(benchResult);
+}
+
+BMK_benchOutcome_t BMK_benchMemAdvanced(const void* srcBuffer, size_t srcSize,
+                        void* dstBuffer, size_t dstCapacity,
+                        const size_t* fileSizes, unsigned nbFiles,
+                        int cLevel, const ZSTD_compressionParameters* comprParams,
+                        const void* dictBuffer, size_t dictBufferSize,
+                        int displayLevel, const char* displayName, const BMK_advancedParams_t* adv)
+
+{
+    int const dstParamsError = !dstBuffer ^ !dstCapacity;  /* must be both NULL or none */
+
+    size_t const blockSize = ((adv->blockSize>=32 && (adv->mode != BMK_decodeOnly)) ? adv->blockSize : srcSize) + (!srcSize) /* avoid div by 0 */ ;
+    U32 const maxNbBlocks = (U32) ((srcSize + (blockSize-1)) / blockSize) + nbFiles;
+
+    /* these are the blockTable parameters, just split up */
+    const void ** const srcPtrs = (const void**)malloc(maxNbBlocks * sizeof(void*));
+    size_t* const srcSizes = (size_t*)malloc(maxNbBlocks * sizeof(size_t));
+
+
+    void ** const cPtrs = (void**)malloc(maxNbBlocks * sizeof(void*));
+    size_t* const cSizes = (size_t*)malloc(maxNbBlocks * sizeof(size_t));
+    size_t* const cCapacities = (size_t*)malloc(maxNbBlocks * sizeof(size_t));
+
+    void ** const resPtrs = (void**)malloc(maxNbBlocks * sizeof(void*));
+    size_t* const resSizes = (size_t*)malloc(maxNbBlocks * sizeof(size_t));
+
+    BMK_timedFnState_t* timeStateCompress = BMK_createTimedFnState(adv->nbSeconds * 1000, BMK_RUNTEST_DEFAULT_MS);
+    BMK_timedFnState_t* timeStateDecompress = BMK_createTimedFnState(adv->nbSeconds * 1000, BMK_RUNTEST_DEFAULT_MS);
+
+    ZSTD_CCtx* const cctx = ZSTD_createCCtx();
+    ZSTD_DCtx* const dctx = ZSTD_createDCtx();
+
+    const size_t maxCompressedSize = dstCapacity ? dstCapacity : ZSTD_compressBound(srcSize) + (maxNbBlocks * 1024);
+
+    void* const internalDstBuffer = dstBuffer ? NULL : malloc(maxCompressedSize);
+    void* const compressedBuffer = dstBuffer ? dstBuffer : internalDstBuffer;
+
+    BMK_benchOutcome_t outcome = BMK_benchOutcome_error();  /* error by default */
+
+    void* resultBuffer = srcSize ? malloc(srcSize) : NULL;
+
+    int allocationincomplete = !srcPtrs || !srcSizes || !cPtrs ||
+        !cSizes || !cCapacities || !resPtrs || !resSizes ||
+        !timeStateCompress || !timeStateDecompress ||
+        !cctx || !dctx ||
+        !compressedBuffer || !resultBuffer;
+
+
+    if (!allocationincomplete && !dstParamsError) {
+        outcome = BMK_benchMemAdvancedNoAlloc(srcPtrs, srcSizes,
+                                            cPtrs, cCapacities, cSizes,
+                                            resPtrs, resSizes,
+                                            &resultBuffer,
+                                            compressedBuffer, maxCompressedSize,
+                                            timeStateCompress, timeStateDecompress,
+                                            srcBuffer, srcSize,
+                                            fileSizes, nbFiles,
+                                            cLevel, comprParams,
+                                            dictBuffer, dictBufferSize,
+                                            cctx, dctx,
+                                            displayLevel, displayName, adv);
+    }
+
+    /* clean up */
+    BMK_freeTimedFnState(timeStateCompress);
+    BMK_freeTimedFnState(timeStateDecompress);
+
+    ZSTD_freeCCtx(cctx);
+    ZSTD_freeDCtx(dctx);
+
+    free(internalDstBuffer);
+    free(resultBuffer);
+
+    free((void*)srcPtrs);
+    free(srcSizes);
+    free(cPtrs);
+    free(cSizes);
+    free(cCapacities);
+    free(resPtrs);
+    free(resSizes);
+
+    if(allocationincomplete) {
+        RETURN_ERROR(31, BMK_benchOutcome_t, "allocation error : not enough memory");
+    }
+
+    if(dstParamsError) {
+        RETURN_ERROR(32, BMK_benchOutcome_t, "Dst parameters not coherent");
+    }
+    return outcome;
+}
+
+BMK_benchOutcome_t BMK_benchMem(const void* srcBuffer, size_t srcSize,
+                        const size_t* fileSizes, unsigned nbFiles,
+                        int cLevel, const ZSTD_compressionParameters* comprParams,
+                        const void* dictBuffer, size_t dictBufferSize,
+                        int displayLevel, const char* displayName) {
+
+    BMK_advancedParams_t const adv = BMK_initAdvancedParams();
+    return BMK_benchMemAdvanced(srcBuffer, srcSize,
+                                NULL, 0,
+                                fileSizes, nbFiles,
+                                cLevel, comprParams,
+                                dictBuffer, dictBufferSize,
+                                displayLevel, displayName, &adv);
+}
+
+static BMK_benchOutcome_t BMK_benchCLevel(const void* srcBuffer, size_t benchedSize,
+                            const size_t* fileSizes, unsigned nbFiles,
+                            int cLevel, const ZSTD_compressionParameters* comprParams,
+                            const void* dictBuffer, size_t dictBufferSize,
+                            int displayLevel, const char* displayName,
+                            BMK_advancedParams_t const * const adv)
+{
+    const char* pch = strrchr(displayName, '\\'); /* Windows */
+    if (!pch) pch = strrchr(displayName, '/');    /* Linux */
+    if (pch) displayName = pch+1;
+
+    if (adv->realTime) {
+        DISPLAYLEVEL(2, "Note : switching to real-time priority \n");
+        SET_REALTIME_PRIORITY;
+    }
+
+    if (displayLevel == 1 && !adv->additionalParam)   /* --quiet mode */
+        DISPLAY("bench %s %s: input %u bytes, %u seconds, %u KB blocks\n",
+                ZSTD_VERSION_STRING, ZSTD_GIT_COMMIT_STRING,
+                (unsigned)benchedSize, adv->nbSeconds, (unsigned)(adv->blockSize>>10));
+
+    return BMK_benchMemAdvanced(srcBuffer, benchedSize,
+                                NULL, 0,
+                                fileSizes, nbFiles,
+                                cLevel, comprParams,
+                                dictBuffer, dictBufferSize,
+                                displayLevel, displayName, adv);
+}
+
+BMK_benchOutcome_t BMK_syntheticTest(int cLevel, double compressibility,
+                          const ZSTD_compressionParameters* compressionParams,
+                          int displayLevel, const BMK_advancedParams_t* adv)
+{
+    char name[20] = {0};
+    size_t const benchedSize = 10000000;
+    void* srcBuffer;
+    BMK_benchOutcome_t res;
+
+    if (cLevel > ZSTD_maxCLevel()) {
+        RETURN_ERROR(15, BMK_benchOutcome_t, "Invalid Compression Level");
+    }
+
+    /* Memory allocation */
+    srcBuffer = malloc(benchedSize);
+    if (!srcBuffer) RETURN_ERROR(21, BMK_benchOutcome_t, "not enough memory");
+
+    /* Fill input buffer */
+    RDG_genBuffer(srcBuffer, benchedSize, compressibility, 0.0, 0);
+
+    /* Bench */
+    snprintf (name, sizeof(name), "Synthetic %2u%%", (unsigned)(compressibility*100));
+    res = BMK_benchCLevel(srcBuffer, benchedSize,
+                    &benchedSize /* ? */, 1 /* ? */,
+                    cLevel, compressionParams,
+                    NULL, 0,  /* dictionary */
+                    displayLevel, name, adv);
+
+    /* clean up */
+    free(srcBuffer);
+
+    return res;
+}
+
+
+
+static size_t BMK_findMaxMem(U64 requiredMem)
+{
+    size_t const step = 64 MB;
+    BYTE* testmem = NULL;
+
+    requiredMem = (((requiredMem >> 26) + 1) << 26);
+    requiredMem += step;
+    if (requiredMem > maxMemory) requiredMem = maxMemory;
+
+    do {
+        testmem = (BYTE*)malloc((size_t)requiredMem);
+        requiredMem -= step;
+    } while (!testmem && requiredMem > 0);
+
+    free(testmem);
+    return (size_t)(requiredMem);
+}
+
+/*! BMK_loadFiles() :
+ *  Loads `buffer` with content of files listed within `fileNamesTable`.
+ *  At most, fills `buffer` entirely. */
+static int BMK_loadFiles(void* buffer, size_t bufferSize,
+                         size_t* fileSizes,
+                         const char* const * fileNamesTable, unsigned nbFiles,
+                         int displayLevel)
+{
+    size_t pos = 0, totalSize = 0;
+    unsigned n;
+    for (n=0; n<nbFiles; n++) {
+        U64 fileSize = UTIL_getFileSize(fileNamesTable[n]);  /* last file may be shortened */
+        if (UTIL_isDirectory(fileNamesTable[n])) {
+            DISPLAYLEVEL(2, "Ignoring %s directory...       \n", fileNamesTable[n]);
+            fileSizes[n] = 0;
+            continue;
+        }
+        if (fileSize == UTIL_FILESIZE_UNKNOWN) {
+            DISPLAYLEVEL(2, "Cannot evaluate size of %s, ignoring ... \n", fileNamesTable[n]);
+            fileSizes[n] = 0;
+            continue;
+        }
+        {   FILE* const f = fopen(fileNamesTable[n], "rb");
+            if (f==NULL) RETURN_ERROR_INT(10, "impossible to open file %s", fileNamesTable[n]);
+            DISPLAYUPDATE(2, "Loading %s...       \r", fileNamesTable[n]);
+            if (fileSize > bufferSize-pos) fileSize = bufferSize-pos, nbFiles=n;   /* buffer too small - stop after this file */
+            {   size_t const readSize = fread(((char*)buffer)+pos, 1, (size_t)fileSize, f);
+                if (readSize != (size_t)fileSize) RETURN_ERROR_INT(11, "could not read %s", fileNamesTable[n]);
+                pos += readSize;
+            }
+            fileSizes[n] = (size_t)fileSize;
+            totalSize += (size_t)fileSize;
+            fclose(f);
+    }   }
+
+    if (totalSize == 0) RETURN_ERROR_INT(12, "no data to bench");
+    return 0;
+}
+
+BMK_benchOutcome_t BMK_benchFilesAdvanced(
+                        const char* const * fileNamesTable, unsigned nbFiles,
+                        const char* dictFileName, int cLevel,
+                        const ZSTD_compressionParameters* compressionParams,
+                        int displayLevel, const BMK_advancedParams_t* adv)
+{
+    void* srcBuffer = NULL;
+    size_t benchedSize;
+    void* dictBuffer = NULL;
+    size_t dictBufferSize = 0;
+    size_t* fileSizes = NULL;
+    BMK_benchOutcome_t res;
+    U64 const totalSizeToLoad = UTIL_getTotalFileSize(fileNamesTable, nbFiles);
+
+    if (!nbFiles) {
+        RETURN_ERROR(14, BMK_benchOutcome_t, "No Files to Benchmark");
+    }
+
+    if (cLevel > ZSTD_maxCLevel()) {
+        RETURN_ERROR(15, BMK_benchOutcome_t, "Invalid Compression Level");
+    }
+
+    fileSizes = (size_t*)calloc(nbFiles, sizeof(size_t));
+    if (!fileSizes) RETURN_ERROR(12, BMK_benchOutcome_t, "not enough memory for fileSizes");
+
+    /* Load dictionary */
+    if (dictFileName != NULL) {
+        U64 const dictFileSize = UTIL_getFileSize(dictFileName);
+        if (dictFileSize == UTIL_FILESIZE_UNKNOWN) {
+            DISPLAYLEVEL(1, "error loading %s : %s \n", dictFileName, strerror(errno));
+            free(fileSizes);
+            RETURN_ERROR(9, BMK_benchOutcome_t, "benchmark aborted");
+        }
+        if (dictFileSize > 64 MB) {
+            free(fileSizes);
+            RETURN_ERROR(10, BMK_benchOutcome_t, "dictionary file %s too large", dictFileName);
+        }
+        dictBufferSize = (size_t)dictFileSize;
+        dictBuffer = malloc(dictBufferSize);
+        if (dictBuffer==NULL) {
+            free(fileSizes);
+            RETURN_ERROR(11, BMK_benchOutcome_t, "not enough memory for dictionary (%u bytes)",
+                            (unsigned)dictBufferSize);
+        }
+
+        {   int const errorCode = BMK_loadFiles(dictBuffer, dictBufferSize,
+                                                fileSizes, &dictFileName /*?*/,
+                                                1 /*?*/, displayLevel);
+            if (errorCode) {
+                res = BMK_benchOutcome_error();
+                goto _cleanUp;
+        }   }
+    }
+
+    /* Memory allocation & restrictions */
+    benchedSize = BMK_findMaxMem(totalSizeToLoad * 3) / 3;
+    if ((U64)benchedSize > totalSizeToLoad) benchedSize = (size_t)totalSizeToLoad;
+    if (benchedSize < totalSizeToLoad)
+        DISPLAY("Not enough memory; testing %u MB only...\n", (unsigned)(benchedSize >> 20));
+
+    srcBuffer = benchedSize ? malloc(benchedSize) : NULL;
+    if (!srcBuffer) {
+        free(dictBuffer);
+        free(fileSizes);
+        RETURN_ERROR(12, BMK_benchOutcome_t, "not enough memory");
+    }
+
+    /* Load input buffer */
+    {   int const errorCode = BMK_loadFiles(srcBuffer, benchedSize,
+                                        fileSizes, fileNamesTable, nbFiles,
+                                        displayLevel);
+        if (errorCode) {
+            res = BMK_benchOutcome_error();
+            goto _cleanUp;
+    }   }
+
+    /* Bench */
+    {   char mfName[20] = {0};
+        snprintf (mfName, sizeof(mfName), " %u files", nbFiles);
+        {   const char* const displayName = (nbFiles > 1) ? mfName : fileNamesTable[0];
+            res = BMK_benchCLevel(srcBuffer, benchedSize,
+                                fileSizes, nbFiles,
+                                cLevel, compressionParams,
+                                dictBuffer, dictBufferSize,
+                                displayLevel, displayName,
+                                adv);
+    }   }
+
+_cleanUp:
+    free(srcBuffer);
+    free(dictBuffer);
+    free(fileSizes);
+    return res;
+}
+
+
+BMK_benchOutcome_t BMK_benchFiles(
+                    const char* const * fileNamesTable, unsigned nbFiles,
+                    const char* dictFileName,
+                    int cLevel, const ZSTD_compressionParameters* compressionParams,
+                    int displayLevel)
+{
+    BMK_advancedParams_t const adv = BMK_initAdvancedParams();
+    return BMK_benchFilesAdvanced(fileNamesTable, nbFiles, dictFileName, cLevel, compressionParams, displayLevel, &adv);
+}
diff --git a/src/zstd/programs/benchzstd.h b/src/zstd/programs/benchzstd.h
new file mode 100644
index 000000000..8c55b3c4f
--- /dev/null
+++ b/src/zstd/programs/benchzstd.h
@@ -0,0 +1,212 @@
+/*
+ * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
+ */
+
+ /* benchzstd :
+  * benchmark Zstandard compression / decompression
+  * over a set of files or buffers
+  * and display progress result and final summary
+  */
+
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
+#ifndef BENCH_ZSTD_H_3242387
+#define BENCH_ZSTD_H_3242387
+
+/* ===  Dependencies  === */
+#include <stddef.h>   /* size_t */
+#define ZSTD_STATIC_LINKING_ONLY   /* ZSTD_compressionParameters */
+#include "../lib/zstd.h"     /* ZSTD_compressionParameters */
+
+
+/* ===  Constants  === */
+
+#define MB_UNIT 1000000
+
+
+/* ===  Benchmark functions  === */
+
+/* Creates a variant `typeName`, able to express "error or valid result".
+ * Functions with return type `typeName`
+ * must first check if result is valid, using BMK_isSuccessful_*(),
+ * and only then can extract `baseType`.
+ */
+#define VARIANT_ERROR_RESULT(baseType, variantName)  \
+                                             \
+typedef struct {                             \
+    baseType internal_never_use_directly;    \
+    int tag;                                 \
+} variantName
+
+
+typedef struct {
+    size_t cSize;
+    unsigned long long cSpeed;   /* bytes / sec */
+    unsigned long long dSpeed;
+    size_t cMem;                 /* memory usage during compression */
+} BMK_benchResult_t;
+
+VARIANT_ERROR_RESULT(BMK_benchResult_t, BMK_benchOutcome_t);
+
+/* check first if the return structure represents an error or a valid result */
+int BMK_isSuccessful_benchOutcome(BMK_benchOutcome_t outcome);
+
+/* extract result from variant type.
+ * note : this function will abort() program execution if result is not valid
+ *        check result validity first, by using BMK_isSuccessful_benchOutcome()
+ */
+BMK_benchResult_t BMK_extract_benchResult(BMK_benchOutcome_t outcome);
+
+
+/*! BMK_benchFiles() -- called by zstdcli */
+/*  Loads files from fileNamesTable into memory,
+ *  and an optional dictionary from dictFileName (can be NULL),
+ *  then uses benchMem().
+ *  fileNamesTable - name of files to benchmark.
+ *  nbFiles - number of files (size of fileNamesTable), must be > 0.
+ *  dictFileName - name of dictionary file to load.
+ *  cLevel - compression level to benchmark, errors if invalid.
+ *  compressionParams - advanced compression Parameters.
+ *  displayLevel - what gets printed:
+ *      0 : no display;
+ *      1 : errors;
+ *      2 : + result + interaction + warnings;
+ *      3 : + information;
+ *      4 : + debug
+ * @return:
+ *      a variant, which expresses either an error, or a valid result.
+ *      Use BMK_isSuccessful_benchOutcome() to check if function was successful.
+ *      If yes, extract the valid result with BMK_extract_benchResult(),
+ *      it will contain :
+ *          .cSpeed: compression speed in bytes per second,
+ *          .dSpeed: decompression speed in bytes per second,
+ *          .cSize : compressed size, in bytes
+ *          .cMem  : memory budget required for the compression context
+ */
+BMK_benchOutcome_t BMK_benchFiles(
+                   const char* const * fileNamesTable, unsigned nbFiles,
+                   const char* dictFileName,
+                   int cLevel, const ZSTD_compressionParameters* compressionParams,
+                   int displayLevel);
+
+
+typedef enum {
+    BMK_both = 0,
+    BMK_decodeOnly = 1,
+    BMK_compressOnly = 2
+} BMK_mode_t;
+
+typedef struct {
+    BMK_mode_t mode;        /* 0: all, 1: compress only 2: decode only */
+    unsigned nbSeconds;     /* default timing is in nbSeconds */
+    size_t blockSize;       /* Maximum size of each block*/
+    int nbWorkers;          /* multithreading */
+    unsigned realTime;      /* real time priority */
+    int additionalParam;    /* used by python speed benchmark */
+    int ldmFlag;            /* enables long distance matching */
+    int ldmMinMatch;        /* below: parameters for long distance matching, see zstd.1.md */
+    int ldmHashLog;
+    int ldmBucketSizeLog;
+    int ldmHashRateLog;
+    ZSTD_literalCompressionMode_e literalCompressionMode;
+} BMK_advancedParams_t;
+
+/* returns default parameters used by nonAdvanced functions */
+BMK_advancedParams_t BMK_initAdvancedParams(void);
+
+/*! BMK_benchFilesAdvanced():
+ *  Same as BMK_benchFiles(),
+ *  with more controls, provided through advancedParams_t structure */
+BMK_benchOutcome_t BMK_benchFilesAdvanced(
+                   const char* const * fileNamesTable, unsigned nbFiles,
+                   const char* dictFileName,
+                   int cLevel, const ZSTD_compressionParameters* compressionParams,
+                   int displayLevel, const BMK_advancedParams_t* adv);
+
+/*! BMK_syntheticTest() -- called from zstdcli */
+/*  Generates a sample with datagen, using compressibility argument */
+/*  cLevel - compression level to benchmark, errors if invalid
+ *  compressibility - determines compressibility of sample
+ *  compressionParams - basic compression Parameters
+ *  displayLevel - see benchFiles
+ *  adv - see advanced_Params_t
+ * @return:
+ *      a variant, which expresses either an error, or a valid result.
+ *      Use BMK_isSuccessful_benchOutcome() to check if function was successful.
+ *      If yes, extract the valid result with BMK_extract_benchResult(),
+ *      it will contain :
+ *          .cSpeed: compression speed in bytes per second,
+ *          .dSpeed: decompression speed in bytes per second,
+ *          .cSize : compressed size, in bytes
+ *          .cMem  : memory budget required for the compression context
+ */
+BMK_benchOutcome_t BMK_syntheticTest(
+                          int cLevel, double compressibility,
+                          const ZSTD_compressionParameters* compressionParams,
+                          int displayLevel, const BMK_advancedParams_t* adv);
+
+
+
+/* ===  Benchmark Zstandard in a memory-to-memory scenario  === */
+
+/** BMK_benchMem() -- core benchmarking function, called in paramgrill
+ *  applies ZSTD_compress_generic() and ZSTD_decompress_generic() on data in srcBuffer
+ *  with specific compression parameters provided by other arguments using benchFunction
+ *  (cLevel, comprParams + adv in advanced Mode) */
+/*  srcBuffer - data source, expected to be valid compressed data if in Decode Only Mode
+ *  srcSize - size of data in srcBuffer
+ *  fileSizes - srcBuffer is considered cut into 1+ segments, to compress separately.
+ *              note : sum(fileSizes) must be == srcSize.  (<== ensure it's properly checked)
+ *  nbFiles - nb of segments
+ *  cLevel - compression level
+ *  comprParams - basic compression parameters
+ *  dictBuffer - a dictionary if used, null otherwise
+ *  dictBufferSize - size of dictBuffer, 0 otherwise
+ *  displayLevel - see BMK_benchFiles
+ *  displayName - name used by display
+ * @return:
+ *      a variant, which expresses either an error, or a valid result.
+ *      Use BMK_isSuccessful_benchOutcome() to check if function was successful.
+ *      If yes, extract the valid result with BMK_extract_benchResult(),
+ *      it will contain :
+ *          .cSpeed: compression speed in bytes per second,
+ *          .dSpeed: decompression speed in bytes per second,
+ *          .cSize : compressed size, in bytes
+ *          .cMem  : memory budget required for the compression context
+ */
+BMK_benchOutcome_t BMK_benchMem(const void* srcBuffer, size_t srcSize,
+                        const size_t* fileSizes, unsigned nbFiles,
+                        int cLevel, const ZSTD_compressionParameters* comprParams,
+                        const void* dictBuffer, size_t dictBufferSize,
+                        int displayLevel, const char* displayName);
+
+
+/* BMK_benchMemAdvanced() : same as BMK_benchMem()
+ * with following additional options :
+ * dstBuffer - destination buffer to write compressed output in, NULL if none provided.
+ * dstCapacity - capacity of destination buffer, give 0 if dstBuffer = NULL
+ * adv = see advancedParams_t
+ */
+BMK_benchOutcome_t BMK_benchMemAdvanced(const void* srcBuffer, size_t srcSize,
+                        void* dstBuffer, size_t dstCapacity,
+                        const size_t* fileSizes, unsigned nbFiles,
+                        int cLevel, const ZSTD_compressionParameters* comprParams,
+                        const void* dictBuffer, size_t dictBufferSize,
+                        int displayLevel, const char* displayName,
+                        const BMK_advancedParams_t* adv);
+
+
+
+#endif   /* BENCH_ZSTD_H_3242387 */
+
+#if defined (__cplusplus)
+}
+#endif
diff --git a/src/zstd/programs/datagen.c b/src/zstd/programs/datagen.c
new file mode 100644
index 000000000..4353b7ff9
--- /dev/null
+++ b/src/zstd/programs/datagen.c
@@ -0,0 +1,186 @@
+/*
+ * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
+ */
+
+
+
+/*-************************************
+*  Dependencies
+**************************************/
+#include "datagen.h"
+#include "platform.h"  /* SET_BINARY_MODE */
+#include <stdlib.h>    /* malloc, free */
+#include <stdio.h>     /* FILE, fwrite, fprintf */
+#include <string.h>    /* memcpy */
+#include "../lib/common/mem.h"  /* U32 */
+
+
+/*-************************************
+*  Macros
+**************************************/
+#define KB *(1 <<10)
+#define MIN(a,b)  ( (a) < (b) ? (a) : (b) )
+
+#define RDG_DEBUG 0
+#define TRACE(...)   if (RDG_DEBUG) fprintf(stderr, __VA_ARGS__ )
+
+
+/*-************************************
+*  Local constants
+**************************************/
+#define LTLOG 13
+#define LTSIZE (1<<LTLOG)
+#define LTMASK (LTSIZE-1)
+
+
+/*-*******************************************************
+*  Local Functions
+*********************************************************/
+#define RDG_rotl32(x,r) ((x << r) | (x >> (32 - r)))
+static U32 RDG_rand(U32* src)
+{
+    static const U32 prime1 = 2654435761U;
+    static const U32 prime2 = 2246822519U;
+    U32 rand32 = *src;
+    rand32 *= prime1;
+    rand32 ^= prime2;
+    rand32  = RDG_rotl32(rand32, 13);
+    *src = rand32;
+    return rand32 >> 5;
+}
+
+typedef U32 fixedPoint_24_8;
+
+static void RDG_fillLiteralDistrib(BYTE* ldt, fixedPoint_24_8 ld)
+{
+    BYTE const firstChar = (ld<=0.0) ?   0 : '(';
+    BYTE const lastChar  = (ld<=0.0) ? 255 : '}';
+    BYTE character = (ld<=0.0) ? 0 : '0';
+    U32 u;
+
+    if (ld<=0) ld = 0;
+    for (u=0; u<LTSIZE; ) {
+        U32 const weight = (((LTSIZE - u) * ld) >> 8) + 1;
+        U32 const end = MIN ( u + weight , LTSIZE);
+        while (u < end) ldt[u++] = character;
+        character++;
+        if (character > lastChar) character = firstChar;
+    }
+}
+
+
+static BYTE RDG_genChar(U32* seed, const BYTE* ldt)
+{
+    U32 const id = RDG_rand(seed) & LTMASK;
+    return ldt[id];  /* memory-sanitizer fails here, stating "uninitialized value" when table initialized with P==0.0. Checked : table is fully initialized */
+}
+
+
+static U32 RDG_rand15Bits (U32* seedPtr)
+{
+    return RDG_rand(seedPtr) & 0x7FFF;
+}
+
+static U32 RDG_randLength(U32* seedPtr)
+{
+    if (RDG_rand(seedPtr) & 7) return (RDG_rand(seedPtr) & 0xF);   /* small length */
+    return (RDG_rand(seedPtr) & 0x1FF) + 0xF;
+}
+
+static void RDG_genBlock(void* buffer, size_t buffSize, size_t prefixSize,
+                         double matchProba, const BYTE* ldt, U32* seedPtr)
+{
+    BYTE* const buffPtr = (BYTE*)buffer;
+    U32 const matchProba32 = (U32)(32768 * matchProba);
+    size_t pos = prefixSize;
+    U32 prevOffset = 1;
+
+    /* special case : sparse content */
+    while (matchProba >= 1.0) {
+        size_t size0 = RDG_rand(seedPtr) & 3;
+        size0  = (size_t)1 << (16 + size0 * 2);
+        size0 += RDG_rand(seedPtr) & (size0-1);   /* because size0 is power of 2*/
+        if (buffSize < pos + size0) {
+            memset(buffPtr+pos, 0, buffSize-pos);
+            return;
+        }
+        memset(buffPtr+pos, 0, size0);
+        pos += size0;
+        buffPtr[pos-1] = RDG_genChar(seedPtr, ldt);
+        continue;
+    }
+
+    /* init */
+    if (pos==0) buffPtr[0] = RDG_genChar(seedPtr, ldt), pos=1;
+
+    /* Generate compressible data */
+    while (pos < buffSize) {
+        /* Select : Literal (char) or Match (within 32K) */
+        if (RDG_rand15Bits(seedPtr) < matchProba32) {
+            /* Copy (within 32K) */
+            U32 const length = RDG_randLength(seedPtr) + 4;
+            U32 const d = (U32) MIN(pos + length , buffSize);
+            U32 const repeatOffset = (RDG_rand(seedPtr) & 15) == 2;
+            U32 const randOffset = RDG_rand15Bits(seedPtr) + 1;
+            U32 const offset = repeatOffset ? prevOffset : (U32) MIN(randOffset , pos);
+            size_t match = pos - offset;
+            while (pos < d) { buffPtr[pos++] = buffPtr[match++];   /* correctly manages overlaps */ }
+            prevOffset = offset;
+        } else {
+            /* Literal (noise) */
+            U32 const length = RDG_randLength(seedPtr);
+            U32 const d = (U32) MIN(pos + length, buffSize);
+            while (pos < d) { buffPtr[pos++] = RDG_genChar(seedPtr, ldt); }
+    }   }
+}
+
+
+void RDG_genBuffer(void* buffer, size_t size, double matchProba, double litProba, unsigned seed)
+{
+    U32 seed32 = seed;
+    BYTE ldt[LTSIZE];
+    memset(ldt, '0', sizeof(ldt));  /* yes, character '0', this is intentional */
+    if (litProba<=0.0) litProba = matchProba / 4.5;
+    RDG_fillLiteralDistrib(ldt, (fixedPoint_24_8)(litProba * 256 + 0.001));
+    RDG_genBlock(buffer, size, 0, matchProba, ldt, &seed32);
+}
+
+
+void RDG_genStdout(unsigned long long size, double matchProba, double litProba, unsigned seed)
+{
+    U32 seed32 = seed;
+    size_t const stdBlockSize = 128 KB;
+    size_t const stdDictSize = 32 KB;
+    BYTE* const buff = (BYTE*)malloc(stdDictSize + stdBlockSize);
+    U64 total = 0;
+    BYTE ldt[LTSIZE];   /* literals distribution table */
+
+    /* init */
+    if (buff==NULL) { perror("datagen"); exit(1); }
+    if (litProba<=0.0) litProba = matchProba / 4.5;
+    memset(ldt, '0', sizeof(ldt));   /* yes, character '0', this is intentional */
+    RDG_fillLiteralDistrib(ldt, (fixedPoint_24_8)(litProba * 256 + 0.001));
+    SET_BINARY_MODE(stdout);
+
+    /* Generate initial dict */
+    RDG_genBlock(buff, stdDictSize, 0, matchProba, ldt, &seed32);
+
+    /* Generate compressible data */
+    while (total < size) {
+        size_t const genBlockSize = (size_t) (MIN (stdBlockSize, size-total));
+        RDG_genBlock(buff, stdDictSize+stdBlockSize, stdDictSize, matchProba, ldt, &seed32);
+        total += genBlockSize;
+        { size_t const unused = fwrite(buff, 1, genBlockSize, stdout); (void)unused; }
+        /* update dict */
+        memcpy(buff, buff + stdBlockSize, stdDictSize);
+    }
+
+    /* cleanup */
+    free(buff);
+}
diff --git a/src/zstd/programs/datagen.h b/src/zstd/programs/datagen.h
new file mode 100644
index 000000000..5a2682d8f
--- /dev/null
+++ b/src/zstd/programs/datagen.h
@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
+ */
+
+
+#ifndef DATAGEN_H
+#define DATAGEN_H
+
+#include <stddef.h>   /* size_t */
+
+void RDG_genStdout(unsigned long long size, double matchProba, double litProba, unsigned seed);
+void RDG_genBuffer(void* buffer, size_t size, double matchProba, double litProba, unsigned seed);
+/*!RDG_genBuffer
+   Generate 'size' bytes of compressible data into 'buffer'.
+   Compressibility can be controlled using 'matchProba', which is floating point value between 0 and 1.
+   'LitProba' is optional, it affect variability of individual bytes. If litProba==0.0, default value will be used.
+   Generated data pattern can be modified using different 'seed'.
+   For a triplet (matchProba, litProba, seed), the function always generate the same content.
+
+   RDG_genStdout
+   Same as RDG_genBuffer, but generates data into stdout
+*/
+
+#endif
diff --git a/src/zstd/programs/dibio.c b/src/zstd/programs/dibio.c
new file mode 100644
index 000000000..463095a8e
--- /dev/null
+++ b/src/zstd/programs/dibio.c
@@ -0,0 +1,372 @@
+/*
+ * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
+ */
+
+
+
+/* **************************************
+*  Compiler Warnings
+****************************************/
+#ifdef _MSC_VER
+#  pragma warning(disable : 4127)    /* disable: C4127: conditional expression is constant */
+#endif
+
+
+/*-*************************************
+*  Includes
+***************************************/
+#include "platform.h"       /* Large Files support */
+#include "util.h"           /* UTIL_getFileSize, UTIL_getTotalFileSize */
+#include <stdlib.h>         /* malloc, free */
+#include <string.h>         /* memset */
+#include <stdio.h>          /* fprintf, fopen, ftello64 */
+#include <errno.h>          /* errno */
+#include <assert.h>
+
+#include "timefn.h"         /* UTIL_time_t, UTIL_clockSpanMicro, UTIL_getTime */
+#include "../lib/common/mem.h"  /* read */
+#include "../lib/common/error_private.h"
+#include "dibio.h"
+
+
+/*-*************************************
+*  Constants
+***************************************/
+#define KB *(1 <<10)
+#define MB *(1 <<20)
+#define GB *(1U<<30)
+
+#define SAMPLESIZE_MAX (128 KB)
+#define MEMMULT 11    /* rough estimation : memory cost to analyze 1 byte of sample */
+#define COVER_MEMMULT 9    /* rough estimation : memory cost to analyze 1 byte of sample */
+#define FASTCOVER_MEMMULT 1    /* rough estimation : memory cost to analyze 1 byte of sample */
+static const size_t g_maxMemory = (sizeof(size_t) == 4) ? (2 GB - 64 MB) : ((size_t)(512 MB) << sizeof(size_t));
+
+#define NOISELENGTH 32
+
+
+/*-*************************************
+*  Console display
+***************************************/
+#define DISPLAY(...)         fprintf(stderr, __VA_ARGS__)
+#define DISPLAYLEVEL(l, ...) if (displayLevel>=l) { DISPLAY(__VA_ARGS__); }
+
+static const U64 g_refreshRate = SEC_TO_MICRO / 6;
+static UTIL_time_t g_displayClock = UTIL_TIME_INITIALIZER;
+
+#define DISPLAYUPDATE(l, ...) { if (displayLevel>=l) { \
+            if ((UTIL_clockSpanMicro(g_displayClock) > g_refreshRate) || (displayLevel>=4)) \
+            { g_displayClock = UTIL_getTime(); DISPLAY(__VA_ARGS__); \
+            if (displayLevel>=4) fflush(stderr); } } }
+
+/*-*************************************
+*  Exceptions
+***************************************/
+#ifndef DEBUG
+#  define DEBUG 0
+#endif
+#define DEBUGOUTPUT(...) if (DEBUG) DISPLAY(__VA_ARGS__);
+#define EXM_THROW(error, ...)                                             \
+{                                                                         \
+    DEBUGOUTPUT("Error defined at %s, line %i : \n", __FILE__, __LINE__); \
+    DISPLAY("Error %i : ", error);                                        \
+    DISPLAY(__VA_ARGS__);                                                 \
+    DISPLAY("\n");                                                        \
+    exit(error);                                                          \
+}
+
+
+/* ********************************************************
+*  Helper functions
+**********************************************************/
+#undef MIN
+#define MIN(a,b)    ((a) < (b) ? (a) : (b))
+
+
+/* ********************************************************
+*  File related operations
+**********************************************************/
+/** DiB_loadFiles() :
+ *  load samples from files listed in fileNamesTable into buffer.
+ *  works even if buffer is too small to load all samples.
+ *  Also provides the size of each sample into sampleSizes table
+ *  which must be sized correctly, using DiB_fileStats().
+ * @return : nb of samples effectively loaded into `buffer`
+ * *bufferSizePtr is modified, it provides the amount data loaded within buffer.
+ *  sampleSizes is filled with the size of each sample.
+ */
+static unsigned DiB_loadFiles(void* buffer, size_t* bufferSizePtr,
+                              size_t* sampleSizes, unsigned sstSize,
+                              const char** fileNamesTable, unsigned nbFiles, size_t targetChunkSize,
+                              unsigned displayLevel)
+{
+    char* const buff = (char*)buffer;
+    size_t pos = 0;
+    unsigned nbLoadedChunks = 0, fileIndex;
+
+    for (fileIndex=0; fileIndex<nbFiles; fileIndex++) {
+        const char* const fileName = fileNamesTable[fileIndex];
+        unsigned long long const fs64 = UTIL_getFileSize(fileName);
+        unsigned long long remainingToLoad = (fs64 == UTIL_FILESIZE_UNKNOWN) ? 0 : fs64;
+        U32 const nbChunks = targetChunkSize ? (U32)((fs64 + (targetChunkSize-1)) / targetChunkSize) : 1;
+        U64 const chunkSize = targetChunkSize ? MIN(targetChunkSize, fs64) : fs64;
+        size_t const maxChunkSize = (size_t)MIN(chunkSize, SAMPLESIZE_MAX);
+        U32 cnb;
+        FILE* const f = fopen(fileName, "rb");
+        if (f==NULL) EXM_THROW(10, "zstd: dictBuilder: %s %s ", fileName, strerror(errno));
+        DISPLAYUPDATE(2, "Loading %s...       \r", fileName);
+        for (cnb=0; cnb<nbChunks; cnb++) {
+            size_t const toLoad = (size_t)MIN(maxChunkSize, remainingToLoad);
+            if (toLoad > *bufferSizePtr-pos) break;
+            {   size_t const readSize = fread(buff+pos, 1, toLoad, f);
+                if (readSize != toLoad) EXM_THROW(11, "Pb reading %s", fileName);
+                pos += readSize;
+                sampleSizes[nbLoadedChunks++] = toLoad;
+                remainingToLoad -= targetChunkSize;
+                if (nbLoadedChunks == sstSize) { /* no more space left in sampleSizes table */
+                    fileIndex = nbFiles;  /* stop there */
+                    break;
+                }
+                if (toLoad < targetChunkSize) {
+                    fseek(f, (long)(targetChunkSize - toLoad), SEEK_CUR);
+        }   }   }
+        fclose(f);
+    }
+    DISPLAYLEVEL(2, "\r%79s\r", "");
+    *bufferSizePtr = pos;
+    DISPLAYLEVEL(4, "loaded : %u KB \n", (unsigned)(pos >> 10))
+    return nbLoadedChunks;
+}
+
+#define DiB_rotl32(x,r) ((x << r) | (x >> (32 - r)))
+static U32 DiB_rand(U32* src)
+{
+    static const U32 prime1 = 2654435761U;
+    static const U32 prime2 = 2246822519U;
+    U32 rand32 = *src;
+    rand32 *= prime1;
+    rand32 ^= prime2;
+    rand32  = DiB_rotl32(rand32, 13);
+    *src = rand32;
+    return rand32 >> 5;
+}
+
+/* DiB_shuffle() :
+ * shuffle a table of file names in a semi-random way
+ * It improves dictionary quality by reducing "locality" impact, so if sample set is very large,
+ * it will load random elements from it, instead of just the first ones. */
+static void DiB_shuffle(const char** fileNamesTable, unsigned nbFiles) {
+    U32 seed = 0xFD2FB528;
+    unsigned i;
+    assert(nbFiles >= 1);
+    for (i = nbFiles - 1; i > 0; --i) {
+        unsigned const j = DiB_rand(&seed) % (i + 1);
+        const char* const tmp = fileNamesTable[j];
+        fileNamesTable[j] = fileNamesTable[i];
+        fileNamesTable[i] = tmp;
+    }
+}
+
+
+/*-********************************************************
+*  Dictionary training functions
+**********************************************************/
+static size_t DiB_findMaxMem(unsigned long long requiredMem)
+{
+    size_t const step = 8 MB;
+    void* testmem = NULL;
+
+    requiredMem = (((requiredMem >> 23) + 1) << 23);
+    requiredMem += step;
+    if (requiredMem > g_maxMemory) requiredMem = g_maxMemory;
+
+    while (!testmem) {
+        testmem = malloc((size_t)requiredMem);
+        requiredMem -= step;
+    }
+
+    free(testmem);
+    return (size_t)requiredMem;
+}
+
+
+static void DiB_fillNoise(void* buffer, size_t length)
+{
+    unsigned const prime1 = 2654435761U;
+    unsigned const prime2 = 2246822519U;
+    unsigned acc = prime1;
+    size_t p=0;
+
+    for (p=0; p<length; p++) {
+        acc *= prime2;
+        ((unsigned char*)buffer)[p] = (unsigned char)(acc >> 21);
+    }
+}
+
+
+static void DiB_saveDict(const char* dictFileName,
+                         const void* buff, size_t buffSize)
+{
+    FILE* const f = fopen(dictFileName, "wb");
+    if (f==NULL) EXM_THROW(3, "cannot open %s ", dictFileName);
+
+    { size_t const n = fwrite(buff, 1, buffSize, f);
+      if (n!=buffSize) EXM_THROW(4, "%s : write error", dictFileName) }
+
+    { size_t const n = (size_t)fclose(f);
+      if (n!=0) EXM_THROW(5, "%s : flush error", dictFileName) }
+}
+
+
+typedef struct {
+    U64 totalSizeToLoad;
+    unsigned oneSampleTooLarge;
+    unsigned nbSamples;
+} fileStats;
+
+/*! DiB_fileStats() :
+ *  Given a list of files, and a chunkSize (0 == no chunk, whole files)
+ *  provides the amount of data to be loaded and the resulting nb of samples.
+ *  This is useful primarily for allocation purpose => sample buffer, and sample sizes table.
+ */
+static fileStats DiB_fileStats(const char** fileNamesTable, unsigned nbFiles, size_t chunkSize, unsigned displayLevel)
+{
+    fileStats fs;
+    unsigned n;
+    memset(&fs, 0, sizeof(fs));
+    for (n=0; n<nbFiles; n++) {
+        U64 const fileSize = UTIL_getFileSize(fileNamesTable[n]);
+        U64 const srcSize = (fileSize == UTIL_FILESIZE_UNKNOWN) ? 0 : fileSize;
+        U32 const nbSamples = (U32)(chunkSize ? (srcSize + (chunkSize-1)) / chunkSize : 1);
+        U64 const chunkToLoad = chunkSize ? MIN(chunkSize, srcSize) : srcSize;
+        size_t const cappedChunkSize = (size_t)MIN(chunkToLoad, SAMPLESIZE_MAX);
+        fs.totalSizeToLoad += cappedChunkSize * nbSamples;
+        fs.oneSampleTooLarge |= (chunkSize > 2*SAMPLESIZE_MAX);
+        fs.nbSamples += nbSamples;
+    }
+    DISPLAYLEVEL(4, "Preparing to load : %u KB \n", (unsigned)(fs.totalSizeToLoad >> 10));
+    return fs;
+}
+
+
+/*! ZDICT_trainFromBuffer_unsafe_legacy() :
+    Strictly Internal use only !!
+    Same as ZDICT_trainFromBuffer_legacy(), but does not control `samplesBuffer`.
+    `samplesBuffer` must be followed by noisy guard band to avoid out-of-buffer reads.
+    @return : size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`)
+              or an error code.
+*/
+size_t ZDICT_trainFromBuffer_unsafe_legacy(void* dictBuffer, size_t dictBufferCapacity,
+                                           const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples,
+                                           ZDICT_legacy_params_t parameters);
+
+
+int DiB_trainFromFiles(const char* dictFileName, unsigned maxDictSize,
+                       const char** fileNamesTable, unsigned nbFiles, size_t chunkSize,
+                       ZDICT_legacy_params_t* params, ZDICT_cover_params_t* coverParams,
+                       ZDICT_fastCover_params_t* fastCoverParams, int optimize)
+{
+    unsigned const displayLevel = params ? params->zParams.notificationLevel :
+                        coverParams ? coverParams->zParams.notificationLevel :
+                        fastCoverParams ? fastCoverParams->zParams.notificationLevel :
+                        0;   /* should never happen */
+    void* const dictBuffer = malloc(maxDictSize);
+    fileStats const fs = DiB_fileStats(fileNamesTable, nbFiles, chunkSize, displayLevel);
+    size_t* const sampleSizes = (size_t*)malloc(fs.nbSamples * sizeof(size_t));
+    size_t const memMult = params ? MEMMULT :
+                           coverParams ? COVER_MEMMULT:
+                           FASTCOVER_MEMMULT;
+    size_t const maxMem =  DiB_findMaxMem(fs.totalSizeToLoad * memMult) / memMult;
+    size_t loadedSize = (size_t) MIN ((unsigned long long)maxMem, fs.totalSizeToLoad);
+    void* const srcBuffer = malloc(loadedSize+NOISELENGTH);
+    int result = 0;
+
+    /* Checks */
+    if ((!sampleSizes) || (!srcBuffer) || (!dictBuffer))
+        EXM_THROW(12, "not enough memory for DiB_trainFiles");   /* should not happen */
+    if (fs.oneSampleTooLarge) {
+        DISPLAYLEVEL(2, "!  Warning : some sample(s) are very large \n");
+        DISPLAYLEVEL(2, "!  Note that dictionary is only useful for small samples. \n");
+        DISPLAYLEVEL(2, "!  As a consequence, only the first %u bytes of each sample are loaded \n", SAMPLESIZE_MAX);
+    }
+    if (fs.nbSamples < 5) {
+        DISPLAYLEVEL(2, "!  Warning : nb of samples too low for proper processing ! \n");
+        DISPLAYLEVEL(2, "!  Please provide _one file per sample_. \n");
+        DISPLAYLEVEL(2, "!  Alternatively, split files into fixed-size blocks representative of samples, with -B# \n");
+        EXM_THROW(14, "nb of samples too low");   /* we now clearly forbid this case */
+    }
+    if (fs.totalSizeToLoad < (unsigned long long)(8 * maxDictSize)) {
+        DISPLAYLEVEL(2, "!  Warning : data size of samples too small for target dictionary size \n");
+        DISPLAYLEVEL(2, "!  Samples should be about 100x larger than target dictionary size \n");
+    }
+
+    /* init */
+    if (loadedSize < fs.totalSizeToLoad)
+        DISPLAYLEVEL(1, "Not enough memory; training on %u MB only...\n", (unsigned)(loadedSize >> 20));
+
+    /* Load input buffer */
+    DISPLAYLEVEL(3, "Shuffling input files\n");
+    DiB_shuffle(fileNamesTable, nbFiles);
+
+    DiB_loadFiles(srcBuffer, &loadedSize, sampleSizes, fs.nbSamples, fileNamesTable, nbFiles, chunkSize, displayLevel);
+
+    {   size_t dictSize;
+        if (params) {
+            DiB_fillNoise((char*)srcBuffer + loadedSize, NOISELENGTH);   /* guard band, for end of buffer condition */
+            dictSize = ZDICT_trainFromBuffer_unsafe_legacy(dictBuffer, maxDictSize,
+                                                           srcBuffer, sampleSizes, fs.nbSamples,
+                                                           *params);
+        } else if (coverParams) {
+            if (optimize) {
+              dictSize = ZDICT_optimizeTrainFromBuffer_cover(dictBuffer, maxDictSize,
+                                                             srcBuffer, sampleSizes, fs.nbSamples,
+                                                             coverParams);
+              if (!ZDICT_isError(dictSize)) {
+                  unsigned splitPercentage = (unsigned)(coverParams->splitPoint * 100);
+                  DISPLAYLEVEL(2, "k=%u\nd=%u\nsteps=%u\nsplit=%u\n", coverParams->k, coverParams->d,
+                              coverParams->steps, splitPercentage);
+              }
+            } else {
+              dictSize = ZDICT_trainFromBuffer_cover(dictBuffer, maxDictSize, srcBuffer,
+                                                     sampleSizes, fs.nbSamples, *coverParams);
+            }
+        } else {
+            assert(fastCoverParams != NULL);
+            if (optimize) {
+              dictSize = ZDICT_optimizeTrainFromBuffer_fastCover(dictBuffer, maxDictSize,
+                                                              srcBuffer, sampleSizes, fs.nbSamples,
+                                                              fastCoverParams);
+              if (!ZDICT_isError(dictSize)) {
+                unsigned splitPercentage = (unsigned)(fastCoverParams->splitPoint * 100);
+                DISPLAYLEVEL(2, "k=%u\nd=%u\nf=%u\nsteps=%u\nsplit=%u\naccel=%u\n", fastCoverParams->k,
+                            fastCoverParams->d, fastCoverParams->f, fastCoverParams->steps, splitPercentage,
+                            fastCoverParams->accel);
+              }
+            } else {
+              dictSize = ZDICT_trainFromBuffer_fastCover(dictBuffer, maxDictSize, srcBuffer,
+                                                        sampleSizes, fs.nbSamples, *fastCoverParams);
+            }
+        }
+        if (ZDICT_isError(dictSize)) {
+            DISPLAYLEVEL(1, "dictionary training failed : %s \n", ZDICT_getErrorName(dictSize));   /* should not happen */
+            result = 1;
+            goto _cleanup;
+        }
+        /* save dict */
+        DISPLAYLEVEL(2, "Save dictionary of size %u into file %s \n", (unsigned)dictSize, dictFileName);
+        DiB_saveDict(dictFileName, dictBuffer, dictSize);
+    }
+
+    /* clean up */
+_cleanup:
+    free(srcBuffer);
+    free(sampleSizes);
+    free(dictBuffer);
+    return result;
+}
diff --git a/src/zstd/programs/dibio.h b/src/zstd/programs/dibio.h
new file mode 100644
index 000000000..682723d6a
--- /dev/null
+++ b/src/zstd/programs/dibio.h
@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
+ */
+
+/* This library is designed for a single-threaded console application.
+*  It exit() and printf() into stderr when it encounters an error condition. */
+
+#ifndef DIBIO_H_003
+#define DIBIO_H_003
+
+
+/*-*************************************
+*  Dependencies
+***************************************/
+#define ZDICT_STATIC_LINKING_ONLY
+#include "../lib/dictBuilder/zdict.h"     /* ZDICT_params_t */
+
+
+/*-*************************************
+*  Public functions
+***************************************/
+/*! DiB_trainFromFiles() :
+    Train a dictionary from a set of files provided by `fileNamesTable`.
+    Resulting dictionary is written into file `dictFileName`.
+    `parameters` is optional and can be provided with values set to 0, meaning "default".
+    @return : 0 == ok. Any other : error.
+*/
+int DiB_trainFromFiles(const char* dictFileName, unsigned maxDictSize,
+                       const char** fileNamesTable, unsigned nbFiles, size_t chunkSize,
+                       ZDICT_legacy_params_t* params, ZDICT_cover_params_t* coverParams,
+                       ZDICT_fastCover_params_t* fastCoverParams, int optimize);
+
+#endif
diff --git a/src/zstd/programs/fileio.c b/src/zstd/programs/fileio.c
new file mode 100644
index 000000000..d72879d64
--- /dev/null
+++ b/src/zstd/programs/fileio.c
@@ -0,0 +1,2873 @@
+/*
+ * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
+ */
+
+
+/* *************************************
+*  Compiler Options
+***************************************/
+#ifdef _MSC_VER   /* Visual */
+#  pragma warning(disable : 4127)  /* disable: C4127: conditional expression is constant */
+#  pragma warning(disable : 4204)  /* non-constant aggregate initializer */
+#endif
+#if defined(__MINGW32__) && !defined(_POSIX_SOURCE)
+#  define _POSIX_SOURCE 1          /* disable %llu warnings with MinGW on Windows */
+#endif
+
+/*-*************************************
+*  Includes
+***************************************/
+#include "platform.h"   /* Large Files support, SET_BINARY_MODE */
+#include "util.h"       /* UTIL_getFileSize, UTIL_isRegularFile, UTIL_isSameFile */
+#include <stdio.h>      /* fprintf, fopen, fread, _fileno, stdin, stdout */
+#include <stdlib.h>     /* malloc, free */
+#include <string.h>     /* strcmp, strlen */
+#include <assert.h>
+#include <errno.h>      /* errno */
+#include <limits.h>     /* INT_MAX */
+#include <signal.h>
+#include "timefn.h"     /* UTIL_getTime, UTIL_clockSpanMicro */
+
+#if defined (_MSC_VER)
+#  include <sys/stat.h>
+#  include <io.h>
+#endif
+
+#include "../lib/common/mem.h"     /* U32, U64 */
+#include "fileio.h"
+
+#define ZSTD_STATIC_LINKING_ONLY   /* ZSTD_magicNumber, ZSTD_frameHeaderSize_max */
+#include "../lib/zstd.h"
+#include "../lib/common/zstd_errors.h"  /* ZSTD_error_frameParameter_windowTooLarge */
+#include "../lib/compress/zstd_compress_internal.h"
+
+#if defined(ZSTD_GZCOMPRESS) || defined(ZSTD_GZDECOMPRESS)
+#  include <zlib.h>
+#  if !defined(z_const)
+#    define z_const
+#  endif
+#endif
+
+#if defined(ZSTD_LZMACOMPRESS) || defined(ZSTD_LZMADECOMPRESS)
+#  include <lzma.h>
+#endif
+
+#define LZ4_MAGICNUMBER 0x184D2204
+#if defined(ZSTD_LZ4COMPRESS) || defined(ZSTD_LZ4DECOMPRESS)
+#  define LZ4F_ENABLE_OBSOLETE_ENUMS
+#  include <lz4frame.h>
+#  include <lz4.h>
+#endif
+
+
+/*-*************************************
+*  Constants
+***************************************/
+#define ADAPT_WINDOWLOG_DEFAULT 23   /* 8 MB */
+#define DICTSIZE_MAX (32 MB)   /* protection against large input (attack scenario) */
+
+#define FNSPACE 30
+
+/*-*************************************
+*  Macros
+***************************************/
+
+struct FIO_display_prefs_s {
+    int displayLevel;   /* 0 : no display;  1: errors;  2: + result + interaction + warnings;  3: + progression;  4: + information */
+    U32 noProgress;
+};
+
+static FIO_display_prefs_t g_display_prefs = {2, 0};
+
+#define DISPLAY(...)         fprintf(stderr, __VA_ARGS__)
+#define DISPLAYOUT(...)      fprintf(stdout, __VA_ARGS__)
+#define DISPLAYLEVEL(l, ...) { if (g_display_prefs.displayLevel>=l) { DISPLAY(__VA_ARGS__); } }
+
+static const U64 g_refreshRate = SEC_TO_MICRO / 6;
+static UTIL_time_t g_displayClock = UTIL_TIME_INITIALIZER;
+
+#define READY_FOR_UPDATE() (!g_display_prefs.noProgress && UTIL_clockSpanMicro(g_displayClock) > g_refreshRate)
+#define DELAY_NEXT_UPDATE() { g_displayClock = UTIL_getTime(); }
+#define DISPLAYUPDATE(l, ...) {                              \
+        if (g_display_prefs.displayLevel>=l && !g_display_prefs.noProgress) { \
+            if (READY_FOR_UPDATE() || (g_display_prefs.displayLevel>=4)) { \
+                DELAY_NEXT_UPDATE();                         \
+                DISPLAY(__VA_ARGS__);                        \
+                if (g_display_prefs.displayLevel>=4) fflush(stderr);       \
+    }   }   }
+
+#undef MIN  /* in case it would be already defined */
+#define MIN(a,b)    ((a) < (b) ? (a) : (b))
+
+
+#define EXM_THROW(error, ...)                                             \
+{                                                                         \
+    DISPLAYLEVEL(1, "zstd: ");                                            \
+    DISPLAYLEVEL(5, "Error defined at %s, line %i : \n", __FILE__, __LINE__); \
+    DISPLAYLEVEL(1, "error %i : ", error);                                \
+    DISPLAYLEVEL(1, __VA_ARGS__);                                         \
+    DISPLAYLEVEL(1, " \n");                                               \
+    exit(error);                                                          \
+}
+
+#define CHECK_V(v, f)                                \
+    v = f;                                           \
+    if (ZSTD_isError(v)) {                           \
+        DISPLAYLEVEL(5, "%s \n", #f);                \
+        EXM_THROW(11, "%s", ZSTD_getErrorName(v));   \
+    }
+#define CHECK(f) { size_t err; CHECK_V(err, f); }
+
+
+/*-************************************
+*  Signal (Ctrl-C trapping)
+**************************************/
+static const char* g_artefact = NULL;
+static void INThandler(int sig)
+{
+    assert(sig==SIGINT); (void)sig;
+#if !defined(_MSC_VER)
+    signal(sig, SIG_IGN);  /* this invocation generates a buggy warning in Visual Studio */
+#endif
+    if (g_artefact) {
+        assert(UTIL_isRegularFile(g_artefact));
+        remove(g_artefact);
+    }
+    DISPLAY("\n");
+    exit(2);
+}
+static void addHandler(char const* dstFileName)
+{
+    if (UTIL_isRegularFile(dstFileName)) {
+        g_artefact = dstFileName;
+        signal(SIGINT, INThandler);
+    } else {
+        g_artefact = NULL;
+    }
+}
+/* Idempotent */
+static void clearHandler(void)
+{
+    if (g_artefact) signal(SIGINT, SIG_DFL);
+    g_artefact = NULL;
+}
+
+
+/*-*********************************************************
+*  Termination signal trapping (Print debug stack trace)
+***********************************************************/
+#if defined(__has_feature) && !defined(BACKTRACE_ENABLE) /* Clang compiler */
+#  if (__has_feature(address_sanitizer))
+#    define BACKTRACE_ENABLE 0
+#  endif /* __has_feature(address_sanitizer) */
+#elif defined(__SANITIZE_ADDRESS__) && !defined(BACKTRACE_ENABLE) /* GCC compiler */
+#  define BACKTRACE_ENABLE 0
+#endif
+
+#if !defined(BACKTRACE_ENABLE)
+/* automatic detector : backtrace enabled by default on linux+glibc and osx */
+#  if (defined(__linux__) && (defined(__GLIBC__) && !defined(__UCLIBC__))) \
+     || (defined(__APPLE__) && defined(__MACH__))
+#    define BACKTRACE_ENABLE 1
+#  else
+#    define BACKTRACE_ENABLE 0
+#  endif
+#endif
+
+/* note : after this point, BACKTRACE_ENABLE is necessarily defined */
+
+
+#if BACKTRACE_ENABLE
+
+#include <execinfo.h>   /* backtrace, backtrace_symbols */
+
+#define MAX_STACK_FRAMES    50
+
+static void ABRThandler(int sig) {
+    const char* name;
+    void* addrlist[MAX_STACK_FRAMES];
+    char** symbollist;
+    int addrlen, i;
+
+    switch (sig) {
+        case SIGABRT: name = "SIGABRT"; break;
+        case SIGFPE: name = "SIGFPE"; break;
+        case SIGILL: name = "SIGILL"; break;
+        case SIGINT: name = "SIGINT"; break;
+        case SIGSEGV: name = "SIGSEGV"; break;
+        default: name = "UNKNOWN";
+    }
+
+    DISPLAY("Caught %s signal, printing stack:\n", name);
+    /* Retrieve current stack addresses. */
+    addrlen = backtrace(addrlist, MAX_STACK_FRAMES);
+    if (addrlen == 0) {
+        DISPLAY("\n");
+        return;
+    }
+    /* Create readable strings to each frame. */
+    symbollist = backtrace_symbols(addrlist, addrlen);
+    /* Print the stack trace, excluding calls handling the signal. */
+    for (i = ZSTD_START_SYMBOLLIST_FRAME; i < addrlen; i++) {
+        DISPLAY("%s\n", symbollist[i]);
+    }
+    free(symbollist);
+    /* Reset and raise the signal so default handler runs. */
+    signal(sig, SIG_DFL);
+    raise(sig);
+}
+#endif
+
+void FIO_addAbortHandler()
+{
+#if BACKTRACE_ENABLE
+    signal(SIGABRT, ABRThandler);
+    signal(SIGFPE, ABRThandler);
+    signal(SIGILL, ABRThandler);
+    signal(SIGSEGV, ABRThandler);
+    signal(SIGBUS, ABRThandler);
+#endif
+}
+
+
+/*-************************************************************
+* Avoid fseek()'s 2GiB barrier with MSVC, macOS, *BSD, MinGW
+***************************************************************/
+#if defined(_MSC_VER) && _MSC_VER >= 1400
+#   define LONG_SEEK _fseeki64
+#   define LONG_TELL _ftelli64
+#elif !defined(__64BIT__) && (PLATFORM_POSIX_VERSION >= 200112L) /* No point defining Large file for 64 bit */
+#  define LONG_SEEK fseeko
+#  define LONG_TELL ftello
+#elif defined(__MINGW32__) && !defined(__STRICT_ANSI__) && !defined(__NO_MINGW_LFS) && defined(__MSVCRT__)
+#   define LONG_SEEK fseeko64
+#   define LONG_TELL ftello64
+#elif defined(_WIN32) && !defined(__DJGPP__)
+#   include <windows.h>
+    static int LONG_SEEK(FILE* file, __int64 offset, int origin) {
+        LARGE_INTEGER off;
+        DWORD method;
+        off.QuadPart = offset;
+        if (origin == SEEK_END)
+            method = FILE_END;
+        else if (origin == SEEK_CUR)
+            method = FILE_CURRENT;
+        else
+            method = FILE_BEGIN;
+
+        if (SetFilePointerEx((HANDLE) _get_osfhandle(_fileno(file)), off, NULL, method))
+            return 0;
+        else
+            return -1;
+    }
+    static __int64 LONG_TELL(FILE* file) {
+        LARGE_INTEGER off, newOff;
+        off.QuadPart = 0;
+        newOff.QuadPart = 0;
+        SetFilePointerEx((HANDLE) _get_osfhandle(_fileno(file)), off, &newOff, FILE_CURRENT);
+        return newOff.QuadPart;
+    }
+#else
+#   define LONG_SEEK fseek
+#   define LONG_TELL ftell
+#endif
+
+
+/*-*************************************
+*  Parameters: FIO_prefs_t
+***************************************/
+
+/* typedef'd to FIO_prefs_t within fileio.h */
+struct FIO_prefs_s {
+
+    /* Algorithm preferences */
+    FIO_compressionType_t compressionType;
+    U32 sparseFileSupport;   /* 0: no sparse allowed; 1: auto (file yes, stdout no); 2: force sparse */
+    int dictIDFlag;
+    int checksumFlag;
+    int blockSize;
+    int overlapLog;
+    U32 adaptiveMode;
+    int rsyncable;
+    int minAdaptLevel;
+    int maxAdaptLevel;
+    int ldmFlag;
+    int ldmHashLog;
+    int ldmMinMatch;
+    int ldmBucketSizeLog;
+    int ldmHashRateLog;
+    size_t streamSrcSize;
+    size_t targetCBlockSize;
+    int srcSizeHint;
+    int testMode;
+    ZSTD_literalCompressionMode_e literalCompressionMode;
+
+    /* IO preferences */
+    U32 removeSrcFile;
+    U32 overwrite;
+
+    /* Computation resources preferences */
+    unsigned memLimit;
+    int nbWorkers;
+
+    int excludeCompressedFiles;
+    int patchFromMode;
+    int contentSize;
+};
+
+
+/*-*************************************
+*  Parameters: Initialization
+***************************************/
+
+#define FIO_OVERLAP_LOG_NOTSET 9999
+#define FIO_LDM_PARAM_NOTSET 9999
+
+
+FIO_prefs_t* FIO_createPreferences(void)
+{
+    FIO_prefs_t* const ret = (FIO_prefs_t*)malloc(sizeof(FIO_prefs_t));
+    if (!ret) EXM_THROW(21, "Allocation error : not enough memory");
+
+    ret->compressionType = FIO_zstdCompression;
+    ret->overwrite = 0;
+    ret->sparseFileSupport = ZSTD_SPARSE_DEFAULT;
+    ret->dictIDFlag = 1;
+    ret->checksumFlag = 1;
+    ret->removeSrcFile = 0;
+    ret->memLimit = 0;
+    ret->nbWorkers = 1;
+    ret->blockSize = 0;
+    ret->overlapLog = FIO_OVERLAP_LOG_NOTSET;
+    ret->adaptiveMode = 0;
+    ret->rsyncable = 0;
+    ret->minAdaptLevel = -50;   /* initializing this value requires a constant, so ZSTD_minCLevel() doesn't work */
+    ret->maxAdaptLevel = 22;   /* initializing this value requires a constant, so ZSTD_maxCLevel() doesn't work */
+    ret->ldmFlag = 0;
+    ret->ldmHashLog = 0;
+    ret->ldmMinMatch = 0;
+    ret->ldmBucketSizeLog = FIO_LDM_PARAM_NOTSET;
+    ret->ldmHashRateLog = FIO_LDM_PARAM_NOTSET;
+    ret->streamSrcSize = 0;
+    ret->targetCBlockSize = 0;
+    ret->srcSizeHint = 0;
+    ret->testMode = 0;
+    ret->literalCompressionMode = ZSTD_lcm_auto;
+    ret->excludeCompressedFiles = 0;
+    return ret;
+}
+
+void FIO_freePreferences(FIO_prefs_t* const prefs)
+{
+    free(prefs);
+}
+
+
+/*-*************************************
+*  Parameters: Display Options
+***************************************/
+
+void FIO_setNotificationLevel(int level) { g_display_prefs.displayLevel=level; }
+
+void FIO_setNoProgress(unsigned noProgress) { g_display_prefs.noProgress = noProgress; }
+
+
+/*-*************************************
+*  Parameters: Setters
+***************************************/
+
+void FIO_setCompressionType(FIO_prefs_t* const prefs, FIO_compressionType_t compressionType) { prefs->compressionType = compressionType; }
+
+void FIO_overwriteMode(FIO_prefs_t* const prefs) { prefs->overwrite = 1; }
+
+void FIO_setSparseWrite(FIO_prefs_t* const prefs, unsigned sparse) { prefs->sparseFileSupport = sparse; }
+
+void FIO_setDictIDFlag(FIO_prefs_t* const prefs, int dictIDFlag) { prefs->dictIDFlag = dictIDFlag; }
+
+void FIO_setChecksumFlag(FIO_prefs_t* const prefs, int checksumFlag) { prefs->checksumFlag = checksumFlag; }
+
+void FIO_setRemoveSrcFile(FIO_prefs_t* const prefs, unsigned flag) { prefs->removeSrcFile = (flag>0); }
+
+void FIO_setMemLimit(FIO_prefs_t* const prefs, unsigned memLimit) { prefs->memLimit = memLimit; }
+
+void FIO_setNbWorkers(FIO_prefs_t* const prefs, int nbWorkers) {
+#ifndef ZSTD_MULTITHREAD
+    if (nbWorkers > 0) DISPLAYLEVEL(2, "Note : multi-threading is disabled \n");
+#endif
+    prefs->nbWorkers = nbWorkers;
+}
+
+void FIO_setExcludeCompressedFile(FIO_prefs_t* const prefs, int excludeCompressedFiles) { prefs->excludeCompressedFiles = excludeCompressedFiles; }
+
+void FIO_setBlockSize(FIO_prefs_t* const prefs, int blockSize) {
+    if (blockSize && prefs->nbWorkers==0)
+        DISPLAYLEVEL(2, "Setting block size is useless in single-thread mode \n");
+    prefs->blockSize = blockSize;
+}
+
+void FIO_setOverlapLog(FIO_prefs_t* const prefs, int overlapLog){
+    if (overlapLog && prefs->nbWorkers==0)
+        DISPLAYLEVEL(2, "Setting overlapLog is useless in single-thread mode \n");
+    prefs->overlapLog = overlapLog;
+}
+
+void FIO_setAdaptiveMode(FIO_prefs_t* const prefs, unsigned adapt) {
+    if ((adapt>0) && (prefs->nbWorkers==0))
+        EXM_THROW(1, "Adaptive mode is not compatible with single thread mode \n");
+    prefs->adaptiveMode = adapt;
+}
+
+void FIO_setRsyncable(FIO_prefs_t* const prefs, int rsyncable) {
+    if ((rsyncable>0) && (prefs->nbWorkers==0))
+        EXM_THROW(1, "Rsyncable mode is not compatible with single thread mode \n");
+    prefs->rsyncable = rsyncable;
+}
+
+void FIO_setStreamSrcSize(FIO_prefs_t* const prefs, size_t streamSrcSize) {
+    prefs->streamSrcSize = streamSrcSize;
+}
+
+void FIO_setTargetCBlockSize(FIO_prefs_t* const prefs, size_t targetCBlockSize) {
+    prefs->targetCBlockSize = targetCBlockSize;
+}
+
+void FIO_setSrcSizeHint(FIO_prefs_t* const prefs, size_t srcSizeHint) {
+    prefs->srcSizeHint = (int)MIN((size_t)INT_MAX, srcSizeHint);
+}
+
+void FIO_setTestMode(FIO_prefs_t* const prefs, int testMode) {
+    prefs->testMode = (testMode!=0);
+}
+
+void FIO_setLiteralCompressionMode(
+        FIO_prefs_t* const prefs,
+        ZSTD_literalCompressionMode_e mode) {
+    prefs->literalCompressionMode = mode;
+}
+
+void FIO_setAdaptMin(FIO_prefs_t* const prefs, int minCLevel)
+{
+#ifndef ZSTD_NOCOMPRESS
+    assert(minCLevel >= ZSTD_minCLevel());
+#endif
+    prefs->minAdaptLevel = minCLevel;
+}
+
+void FIO_setAdaptMax(FIO_prefs_t* const prefs, int maxCLevel)
+{
+    prefs->maxAdaptLevel = maxCLevel;
+}
+
+void FIO_setLdmFlag(FIO_prefs_t* const prefs, unsigned ldmFlag) {
+    prefs->ldmFlag = (ldmFlag>0);
+}
+
+void FIO_setLdmHashLog(FIO_prefs_t* const prefs, int ldmHashLog) {
+    prefs->ldmHashLog = ldmHashLog;
+}
+
+void FIO_setLdmMinMatch(FIO_prefs_t* const prefs, int ldmMinMatch) {
+    prefs->ldmMinMatch = ldmMinMatch;
+}
+
+void FIO_setLdmBucketSizeLog(FIO_prefs_t* const prefs, int ldmBucketSizeLog) {
+    prefs->ldmBucketSizeLog = ldmBucketSizeLog;
+}
+
+
+void FIO_setLdmHashRateLog(FIO_prefs_t* const prefs, int ldmHashRateLog) {
+    prefs->ldmHashRateLog = ldmHashRateLog;
+}
+
+void FIO_setPatchFromMode(FIO_prefs_t* const prefs, int value)
+{
+    prefs->patchFromMode = value != 0;
+}
+
+void FIO_setContentSize(FIO_prefs_t* const prefs, int value)
+{
+    prefs->contentSize = value != 0;
+}
+
+/*-*************************************
+*  Functions
+***************************************/
+/** FIO_remove() :
+ * @result : Unlink `fileName`, even if it's read-only */
+static int FIO_remove(const char* path)
+{
+    if (!UTIL_isRegularFile(path)) {
+        DISPLAYLEVEL(2, "zstd: Refusing to remove non-regular file %s \n", path);
+        return 0;
+    }
+#if defined(_WIN32) || defined(WIN32)
+    /* windows doesn't allow remove read-only files,
+     * so try to make it writable first */
+    UTIL_chmod(path, _S_IWRITE);
+#endif
+    return remove(path);
+}
+
+/** FIO_openSrcFile() :
+ *  condition : `srcFileName` must be non-NULL.
+ * @result : FILE* to `srcFileName`, or NULL if it fails */
+static FILE* FIO_openSrcFile(const char* srcFileName)
+{
+    assert(srcFileName != NULL);
+    if (!strcmp (srcFileName, stdinmark)) {
+        DISPLAYLEVEL(4,"Using stdin for input \n");
+        SET_BINARY_MODE(stdin);
+        return stdin;
+    }
+
+    if (!UTIL_fileExist(srcFileName)) {
+        DISPLAYLEVEL(1, "zstd: can't stat %s : %s -- ignored \n",
+                        srcFileName, strerror(errno));
+        return NULL;
+    }
+
+    if (!UTIL_isRegularFile(srcFileName)
+     && !UTIL_isFIFO(srcFileName)
+    ) {
+        DISPLAYLEVEL(1, "zstd: %s is not a regular file -- ignored \n",
+                        srcFileName);
+        return NULL;
+    }
+
+    {   FILE* const f = fopen(srcFileName, "rb");
+        if (f == NULL)
+            DISPLAYLEVEL(1, "zstd: %s: %s \n", srcFileName, strerror(errno));
+        return f;
+    }
+}
+
+/** FIO_openDstFile() :
+ *  condition : `dstFileName` must be non-NULL.
+ * @result : FILE* to `dstFileName`, or NULL if it fails */
+static FILE*
+FIO_openDstFile(FIO_prefs_t* const prefs,
+          const char* srcFileName, const char* dstFileName)
+{
+    if (prefs->testMode) return NULL;  /* do not open file in test mode */
+
+    assert(dstFileName != NULL);
+    if (!strcmp (dstFileName, stdoutmark)) {
+        DISPLAYLEVEL(4,"Using stdout for output \n");
+        SET_BINARY_MODE(stdout);
+        if (prefs->sparseFileSupport == 1) {
+            prefs->sparseFileSupport = 0;
+            DISPLAYLEVEL(4, "Sparse File Support is automatically disabled on stdout ; try --sparse \n");
+        }
+        return stdout;
+    }
+
+    /* ensure dst is not the same as src */
+    if (srcFileName != NULL && UTIL_isSameFile(srcFileName, dstFileName)) {
+        DISPLAYLEVEL(1, "zstd: Refusing to open an output file which will overwrite the input file \n");
+        return NULL;
+    }
+
+    if (prefs->sparseFileSupport == 1) {
+        prefs->sparseFileSupport = ZSTD_SPARSE_DEFAULT;
+    }
+
+    if (UTIL_isRegularFile(dstFileName)) {
+        /* Check if destination file already exists */
+        FILE* const fCheck = fopen( dstFileName, "rb" );
+#if !defined(_WIN32)
+        /* this test does not work on Windows :
+         * `NUL` and `nul` are detected as regular files */
+        if (!strcmp(dstFileName, nulmark)) {
+            EXM_THROW(40, "%s is unexpectedly categorized as a regular file",
+                        dstFileName);
+        }
+#endif
+        if (fCheck != NULL) {  /* dst file exists, authorization prompt */
+            fclose(fCheck);
+            if (!prefs->overwrite) {
+                if (g_display_prefs.displayLevel <= 1) {
+                    /* No interaction possible */
+                    DISPLAY("zstd: %s already exists; not overwritten  \n",
+                            dstFileName);
+                    return NULL;
+                }
+                DISPLAY("zstd: %s already exists; overwrite (y/N) ? ",
+                        dstFileName);
+                {   int ch = getchar();
+                    if ((ch!='Y') && (ch!='y')) {
+                        DISPLAY("    not overwritten  \n");
+                        return NULL;
+                    }
+                    /* flush rest of input line */
+                    while ((ch!=EOF) && (ch!='\n')) ch = getchar();
+            }   }
+            /* need to unlink */
+            FIO_remove(dstFileName);
+    }   }
+
+    {   FILE* const f = fopen( dstFileName, "wb" );
+        if (f == NULL) {
+            DISPLAYLEVEL(1, "zstd: %s: %s\n", dstFileName, strerror(errno));
+        } else if (srcFileName != NULL
+               && strcmp (srcFileName, stdinmark)
+               && strcmp(dstFileName, nulmark) ) {
+            /* reduce rights on newly created dst file while compression is ongoing */
+            UTIL_chmod(dstFileName, 00600);
+        }
+        return f;
+    }
+}
+
+
+/*! FIO_createDictBuffer() :
+ *  creates a buffer, pointed by `*bufferPtr`,
+ *  loads `filename` content into it, up to DICTSIZE_MAX bytes.
+ * @return : loaded size
+ *  if fileName==NULL, returns 0 and a NULL pointer
+ */
+static size_t FIO_createDictBuffer(void** bufferPtr, const char* fileName, FIO_prefs_t* const prefs)
+{
+    FILE* fileHandle;
+    U64 fileSize;
+
+    assert(bufferPtr != NULL);
+    *bufferPtr = NULL;
+    if (fileName == NULL) return 0;
+
+    DISPLAYLEVEL(4,"Loading %s as dictionary \n", fileName);
+    fileHandle = fopen(fileName, "rb");
+    if (fileHandle==NULL) EXM_THROW(31, "%s: %s", fileName, strerror(errno));
+
+    fileSize = UTIL_getFileSize(fileName);
+    {
+        size_t const dictSizeMax = prefs->patchFromMode ? prefs->memLimit : DICTSIZE_MAX;
+        if (fileSize >  dictSizeMax) {
+            EXM_THROW(32, "Dictionary file %s is too large (> %u bytes)",
+                            fileName,  (unsigned)dictSizeMax);   /* avoid extreme cases */
+        }
+    }
+    *bufferPtr = malloc((size_t)fileSize);
+    if (*bufferPtr==NULL) EXM_THROW(34, "%s", strerror(errno));
+    {   size_t const readSize = fread(*bufferPtr, 1, (size_t)fileSize, fileHandle);
+        if (readSize != fileSize)
+            EXM_THROW(35, "Error reading dictionary file %s : %s",
+                    fileName, strerror(errno));
+    }
+    fclose(fileHandle);
+    return (size_t)fileSize;
+}
+
+
+
+/* FIO_checkFilenameCollisions() :
+ * Checks for and warns if there are any files that would have the same output path
+ */
+int FIO_checkFilenameCollisions(const char** filenameTable, unsigned nbFiles) {
+    const char **filenameTableSorted, *c, *prevElem, *filename;
+    unsigned u;
+
+    #if defined(_MSC_VER) || defined(__MINGW32__) || defined (__MSVCRT__) /* windows support */
+    c = "\\";
+    #else
+    c = "/";
+    #endif
+
+    filenameTableSorted = (const char**) malloc(sizeof(char*) * nbFiles);
+    if (!filenameTableSorted) {
+        DISPLAY("Unable to malloc new str array, not checking for name collisions\n");
+        return 1;
+    }
+
+    for (u = 0; u < nbFiles; ++u) {
+        filename = strrchr(filenameTable[u], c[0]);
+        if (filename == NULL) {
+            filenameTableSorted[u] = filenameTable[u];
+        } else {
+            filenameTableSorted[u] = filename+1;
+        }
+    }
+
+    qsort((void*)filenameTableSorted, nbFiles, sizeof(char*), UTIL_compareStr);
+    prevElem = filenameTableSorted[0];
+    for (u = 1; u < nbFiles; ++u) {
+        if (strcmp(prevElem, filenameTableSorted[u]) == 0) {
+            DISPLAY("WARNING: Two files have same filename: %s\n", prevElem);
+        }
+        prevElem = filenameTableSorted[u];
+    }
+
+    free((void*)filenameTableSorted);
+    return 0;
+}
+
+static const char*
+extractFilename(const char* path, char separator)
+{
+    const char* search = strrchr(path, separator);
+    if (search == NULL) return path;
+    return search+1;
+}
+
+/* FIO_createFilename_fromOutDir() :
+ * Takes a source file name and specified output directory, and
+ * allocates memory for and returns a pointer to final path.
+ * This function never returns an error (it may abort() in case of pb)
+ */
+static char*
+FIO_createFilename_fromOutDir(const char* path, const char* outDirName, const size_t suffixLen)
+{
+    const char* filenameStart;
+    char separator;
+    char* result;
+
+#if defined(_MSC_VER) || defined(__MINGW32__) || defined (__MSVCRT__) /* windows support */
+    separator = '\\';
+#else
+    separator = '/';
+#endif
+
+    filenameStart = extractFilename(path, separator);
+#if defined(_MSC_VER) || defined(__MINGW32__) || defined (__MSVCRT__) /* windows support */
+    filenameStart = extractFilename(filenameStart, '/');  /* sometimes, '/' separator is also used on Windows (mingw+msys2) */
+#endif
+
+    result = (char*) calloc(1, strlen(outDirName) + 1 + strlen(filenameStart) + suffixLen + 1);
+    if (!result) {
+        EXM_THROW(30, "zstd: FIO_createFilename_fromOutDir: %s", strerror(errno));
+    }
+
+    memcpy(result, outDirName, strlen(outDirName));
+    if (outDirName[strlen(outDirName)-1] == separator) {
+        memcpy(result + strlen(outDirName), filenameStart, strlen(filenameStart));
+    } else {
+        memcpy(result + strlen(outDirName), &separator, 1);
+        memcpy(result + strlen(outDirName) + 1, filenameStart, strlen(filenameStart));
+    }
+
+    return result;
+}
+
+/* FIO_highbit64() :
+ * gives position of highest bit.
+ * note : only works for v > 0 !
+ */
+static unsigned FIO_highbit64(unsigned long long v)
+{
+    unsigned count = 0;
+    assert(v != 0);
+    v >>= 1;
+    while (v) { v >>= 1; count++; }
+    return count;
+}
+
+static void FIO_adjustMemLimitForPatchFromMode(FIO_prefs_t* const prefs,
+                                    unsigned long long const dictSize,
+                                    unsigned long long const maxSrcFileSize)
+{
+    unsigned long long maxSize = MAX(prefs->memLimit, MAX(dictSize, maxSrcFileSize));
+    assert(maxSize != UTIL_FILESIZE_UNKNOWN);
+    if (maxSize > UINT_MAX)
+        EXM_THROW(42, "Can't handle files larger than %u GB\n", UINT_MAX/(1 GB) + 1);
+    FIO_setMemLimit(prefs, (unsigned)maxSize);
+}
+
+#ifndef ZSTD_NOCOMPRESS
+
+/* **********************************************************************
+ *  Compression
+ ************************************************************************/
+typedef struct {
+    FILE* srcFile;
+    FILE* dstFile;
+    void*  srcBuffer;
+    size_t srcBufferSize;
+    void*  dstBuffer;
+    size_t dstBufferSize;
+    void* dictBuffer;
+    size_t dictBufferSize;
+    const char* dictFileName;
+    ZSTD_CStream* cctx;
+} cRess_t;
+
+static void FIO_adjustParamsForPatchFromMode(FIO_prefs_t* const prefs,
+                                    ZSTD_compressionParameters* comprParams,
+                                    unsigned long long const dictSize,
+                                    unsigned long long const maxSrcFileSize,
+                                    int cLevel)
+{
+    unsigned const fileWindowLog = FIO_highbit64(maxSrcFileSize) + 1;
+    ZSTD_compressionParameters const cParams = ZSTD_getCParams(cLevel, (size_t)maxSrcFileSize, (size_t)dictSize);
+    FIO_adjustMemLimitForPatchFromMode(prefs, dictSize, maxSrcFileSize);
+    if (fileWindowLog > ZSTD_WINDOWLOG_MAX)
+        DISPLAYLEVEL(1, "Max window log exceeded by file (compression ratio will suffer)\n");
+    comprParams->windowLog = MIN(ZSTD_WINDOWLOG_MAX, fileWindowLog);
+    if (fileWindowLog > ZSTD_cycleLog(cParams.hashLog, cParams.strategy)) {
+        if (!prefs->ldmFlag)
+            DISPLAYLEVEL(1, "long mode automaticaly triggered\n");
+        FIO_setLdmFlag(prefs, 1);
+    }
+    if (cParams.strategy >= ZSTD_btopt) {
+        DISPLAYLEVEL(1, "[Optimal parser notes] Consider the following to improve patch size at the cost of speed:\n");
+        DISPLAYLEVEL(1, "- Use --single-thread mode in the zstd cli\n");
+        DISPLAYLEVEL(1, "- Set a larger targetLength (eg. --zstd=targetLength=4096)\n");
+        DISPLAYLEVEL(1, "- Set a larger chainLog (eg. --zstd=chainLog=%u)\n", ZSTD_CHAINLOG_MAX);
+        DISPLAYLEVEL(1, "Also consdier playing around with searchLog and hashLog\n");
+    }
+}
+
+static cRess_t FIO_createCResources(FIO_prefs_t* const prefs,
+                                    const char* dictFileName, unsigned long long const maxSrcFileSize,
+                                    int cLevel, ZSTD_compressionParameters comprParams) {
+    cRess_t ress;
+    memset(&ress, 0, sizeof(ress));
+
+    DISPLAYLEVEL(6, "FIO_createCResources \n");
+    ress.cctx = ZSTD_createCCtx();
+    if (ress.cctx == NULL)
+        EXM_THROW(30, "allocation error (%s): can't create ZSTD_CCtx",
+                    strerror(errno));
+    ress.srcBufferSize = ZSTD_CStreamInSize();
+    ress.srcBuffer = malloc(ress.srcBufferSize);
+    ress.dstBufferSize = ZSTD_CStreamOutSize();
+
+    /* need to update memLimit before calling createDictBuffer
+     * because of memLimit check inside it */
+    if (prefs->patchFromMode)
+        FIO_adjustParamsForPatchFromMode(prefs, &comprParams, UTIL_getFileSize(dictFileName), maxSrcFileSize, cLevel);
+    ress.dstBuffer = malloc(ress.dstBufferSize);
+    ress.dictBufferSize = FIO_createDictBuffer(&ress.dictBuffer, dictFileName, prefs);   /* works with dictFileName==NULL */
+    if (!ress.srcBuffer || !ress.dstBuffer)
+        EXM_THROW(31, "allocation error : not enough memory");
+
+    /* Advanced parameters, including dictionary */
+    if (dictFileName && (ress.dictBuffer==NULL))
+        EXM_THROW(32, "allocation error : can't create dictBuffer");
+    ress.dictFileName = dictFileName;
+
+    if (prefs->adaptiveMode && !prefs->ldmFlag && !comprParams.windowLog)
+        comprParams.windowLog = ADAPT_WINDOWLOG_DEFAULT;
+
+    CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_contentSizeFlag, prefs->contentSize) );  /* always enable content size when available (note: supposed to be default) */
+    CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_dictIDFlag, prefs->dictIDFlag) );
+    CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_checksumFlag, prefs->checksumFlag) );
+    /* compression level */
+    CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_compressionLevel, cLevel) );
+    /* max compressed block size */
+    CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_targetCBlockSize, (int)prefs->targetCBlockSize) );
+    /* source size hint */
+    CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_srcSizeHint, (int)prefs->srcSizeHint) );
+    /* long distance matching */
+    CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_enableLongDistanceMatching, prefs->ldmFlag) );
+    CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_ldmHashLog, prefs->ldmHashLog) );
+    CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_ldmMinMatch, prefs->ldmMinMatch) );
+    if (prefs->ldmBucketSizeLog != FIO_LDM_PARAM_NOTSET) {
+        CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_ldmBucketSizeLog, prefs->ldmBucketSizeLog) );
+    }
+    if (prefs->ldmHashRateLog != FIO_LDM_PARAM_NOTSET) {
+        CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_ldmHashRateLog, prefs->ldmHashRateLog) );
+    }
+    /* compression parameters */
+    CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_windowLog, (int)comprParams.windowLog) );
+    CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_chainLog, (int)comprParams.chainLog) );
+    CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_hashLog, (int)comprParams.hashLog) );
+    CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_searchLog, (int)comprParams.searchLog) );
+    CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_minMatch, (int)comprParams.minMatch) );
+    CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_targetLength, (int)comprParams.targetLength) );
+    CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_strategy, comprParams.strategy) );
+    CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_literalCompressionMode, (int)prefs->literalCompressionMode) );
+    /* multi-threading */
+#ifdef ZSTD_MULTITHREAD
+    DISPLAYLEVEL(5,"set nb workers = %u \n", prefs->nbWorkers);
+    CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_nbWorkers, prefs->nbWorkers) );
+    CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_jobSize, prefs->blockSize) );
+    if (prefs->overlapLog != FIO_OVERLAP_LOG_NOTSET) {
+        DISPLAYLEVEL(3,"set overlapLog = %u \n", prefs->overlapLog);
+        CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_overlapLog, prefs->overlapLog) );
+    }
+    CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_rsyncable, prefs->rsyncable) );
+#endif
+    /* dictionary */
+    if (prefs->patchFromMode) {
+        CHECK( ZSTD_CCtx_refPrefix(ress.cctx, ress.dictBuffer, ress.dictBufferSize) );
+    } else {
+        CHECK( ZSTD_CCtx_loadDictionary(ress.cctx, ress.dictBuffer, ress.dictBufferSize) );
+    }
+
+    return ress;
+}
+
+static void FIO_freeCResources(cRess_t ress)
+{
+    free(ress.srcBuffer);
+    free(ress.dstBuffer);
+    free(ress.dictBuffer);
+    ZSTD_freeCStream(ress.cctx);   /* never fails */
+}
+
+
+#ifdef ZSTD_GZCOMPRESS
+static unsigned long long
+FIO_compressGzFrame(const cRess_t* ress,  /* buffers & handlers are used, but not changed */
+                    const char* srcFileName, U64 const srcFileSize,
+                    int compressionLevel, U64* readsize)
+{
+    unsigned long long inFileSize = 0, outFileSize = 0;
+    z_stream strm;
+
+    if (compressionLevel > Z_BEST_COMPRESSION)
+        compressionLevel = Z_BEST_COMPRESSION;
+
+    strm.zalloc = Z_NULL;
+    strm.zfree = Z_NULL;
+    strm.opaque = Z_NULL;
+
+    {   int const ret = deflateInit2(&strm, compressionLevel, Z_DEFLATED,
+                        15 /* maxWindowLogSize */ + 16 /* gzip only */,
+                        8, Z_DEFAULT_STRATEGY); /* see http://www.zlib.net/manual.html */
+        if (ret != Z_OK) {
+            EXM_THROW(71, "zstd: %s: deflateInit2 error %d \n", srcFileName, ret);
+    }   }
+
+    strm.next_in = 0;
+    strm.avail_in = 0;
+    strm.next_out = (Bytef*)ress->dstBuffer;
+    strm.avail_out = (uInt)ress->dstBufferSize;
+
+    while (1) {
+        int ret;
+        if (strm.avail_in == 0) {
+            size_t const inSize = fread(ress->srcBuffer, 1, ress->srcBufferSize, ress->srcFile);
+            if (inSize == 0) break;
+            inFileSize += inSize;
+            strm.next_in = (z_const unsigned char*)ress->srcBuffer;
+            strm.avail_in = (uInt)inSize;
+        }
+        ret = deflate(&strm, Z_NO_FLUSH);
+        if (ret != Z_OK)
+            EXM_THROW(72, "zstd: %s: deflate error %d \n", srcFileName, ret);
+        {   size_t const cSize = ress->dstBufferSize - strm.avail_out;
+            if (cSize) {
+                if (fwrite(ress->dstBuffer, 1, cSize, ress->dstFile) != cSize)
+                    EXM_THROW(73, "Write error : cannot write to output file : %s ", strerror(errno));
+                outFileSize += cSize;
+                strm.next_out = (Bytef*)ress->dstBuffer;
+                strm.avail_out = (uInt)ress->dstBufferSize;
+        }   }
+        if (srcFileSize == UTIL_FILESIZE_UNKNOWN) {
+            DISPLAYUPDATE(2, "\rRead : %u MB ==> %.2f%% ",
+                            (unsigned)(inFileSize>>20),
+                            (double)outFileSize/inFileSize*100)
+        } else {
+            DISPLAYUPDATE(2, "\rRead : %u / %u MB ==> %.2f%% ",
+                            (unsigned)(inFileSize>>20), (unsigned)(srcFileSize>>20),
+                            (double)outFileSize/inFileSize*100);
+    }   }
+
+    while (1) {
+        int const ret = deflate(&strm, Z_FINISH);
+        {   size_t const cSize = ress->dstBufferSize - strm.avail_out;
+            if (cSize) {
+                if (fwrite(ress->dstBuffer, 1, cSize, ress->dstFile) != cSize)
+                    EXM_THROW(75, "Write error : %s ", strerror(errno));
+                outFileSize += cSize;
+                strm.next_out = (Bytef*)ress->dstBuffer;
+                strm.avail_out = (uInt)ress->dstBufferSize;
+        }   }
+        if (ret == Z_STREAM_END) break;
+        if (ret != Z_BUF_ERROR)
+            EXM_THROW(77, "zstd: %s: deflate error %d \n", srcFileName, ret);
+    }
+
+    {   int const ret = deflateEnd(&strm);
+        if (ret != Z_OK) {
+            EXM_THROW(79, "zstd: %s: deflateEnd error %d \n", srcFileName, ret);
+    }   }
+    *readsize = inFileSize;
+    return outFileSize;
+}
+#endif
+
+
+#ifdef ZSTD_LZMACOMPRESS
+static unsigned long long
+FIO_compressLzmaFrame(cRess_t* ress,
+                      const char* srcFileName, U64 const srcFileSize,
+                      int compressionLevel, U64* readsize, int plain_lzma)
+{
+    unsigned long long inFileSize = 0, outFileSize = 0;
+    lzma_stream strm = LZMA_STREAM_INIT;
+    lzma_action action = LZMA_RUN;
+    lzma_ret ret;
+
+    if (compressionLevel < 0) compressionLevel = 0;
+    if (compressionLevel > 9) compressionLevel = 9;
+
+    if (plain_lzma) {
+        lzma_options_lzma opt_lzma;
+        if (lzma_lzma_preset(&opt_lzma, compressionLevel))
+            EXM_THROW(81, "zstd: %s: lzma_lzma_preset error", srcFileName);
+        ret = lzma_alone_encoder(&strm, &opt_lzma); /* LZMA */
+        if (ret != LZMA_OK)
+            EXM_THROW(82, "zstd: %s: lzma_alone_encoder error %d", srcFileName, ret);
+    } else {
+        ret = lzma_easy_encoder(&strm, compressionLevel, LZMA_CHECK_CRC64); /* XZ */
+        if (ret != LZMA_OK)
+            EXM_THROW(83, "zstd: %s: lzma_easy_encoder error %d", srcFileName, ret);
+    }
+
+    strm.next_in = 0;
+    strm.avail_in = 0;
+    strm.next_out = (BYTE*)ress->dstBuffer;
+    strm.avail_out = ress->dstBufferSize;
+
+    while (1) {
+        if (strm.avail_in == 0) {
+            size_t const inSize = fread(ress->srcBuffer, 1, ress->srcBufferSize, ress->srcFile);
+            if (inSize == 0) action = LZMA_FINISH;
+            inFileSize += inSize;
+            strm.next_in = (BYTE const*)ress->srcBuffer;
+            strm.avail_in = inSize;
+        }
+
+        ret = lzma_code(&strm, action);
+
+        if (ret != LZMA_OK && ret != LZMA_STREAM_END)
+            EXM_THROW(84, "zstd: %s: lzma_code encoding error %d", srcFileName, ret);
+        {   size_t const compBytes = ress->dstBufferSize - strm.avail_out;
+            if (compBytes) {
+                if (fwrite(ress->dstBuffer, 1, compBytes, ress->dstFile) != compBytes)
+                    EXM_THROW(85, "Write error : %s", strerror(errno));
+                outFileSize += compBytes;
+                strm.next_out = (BYTE*)ress->dstBuffer;
+                strm.avail_out = ress->dstBufferSize;
+        }   }
+        if (srcFileSize == UTIL_FILESIZE_UNKNOWN)
+            DISPLAYUPDATE(2, "\rRead : %u MB ==> %.2f%%",
+                            (unsigned)(inFileSize>>20),
+                            (double)outFileSize/inFileSize*100)
+        else
+            DISPLAYUPDATE(2, "\rRead : %u / %u MB ==> %.2f%%",
+                            (unsigned)(inFileSize>>20), (unsigned)(srcFileSize>>20),
+                            (double)outFileSize/inFileSize*100);
+        if (ret == LZMA_STREAM_END) break;
+    }
+
+    lzma_end(&strm);
+    *readsize = inFileSize;
+
+    return outFileSize;
+}
+#endif
+
+#ifdef ZSTD_LZ4COMPRESS
+
+#if LZ4_VERSION_NUMBER <= 10600
+#define LZ4F_blockLinked blockLinked
+#define LZ4F_max64KB max64KB
+#endif
+
+static int FIO_LZ4_GetBlockSize_FromBlockId (int id) { return (1 << (8 + (2 * id))); }
+
+static unsigned long long
+FIO_compressLz4Frame(cRess_t* ress,
+                     const char* srcFileName, U64 const srcFileSize,
+                     int compressionLevel, int checksumFlag,
+                     U64* readsize)
+{
+    const size_t blockSize = FIO_LZ4_GetBlockSize_FromBlockId(LZ4F_max64KB);
+    unsigned long long inFileSize = 0, outFileSize = 0;
+
+    LZ4F_preferences_t prefs;
+    LZ4F_compressionContext_t ctx;
+
+    LZ4F_errorCode_t const errorCode = LZ4F_createCompressionContext(&ctx, LZ4F_VERSION);
+    if (LZ4F_isError(errorCode))
+        EXM_THROW(31, "zstd: failed to create lz4 compression context");
+
+    memset(&prefs, 0, sizeof(prefs));
+
+    assert(blockSize <= ress->srcBufferSize);
+
+    prefs.autoFlush = 1;
+    prefs.compressionLevel = compressionLevel;
+    prefs.frameInfo.blockMode = LZ4F_blockLinked;
+    prefs.frameInfo.blockSizeID = LZ4F_max64KB;
+    prefs.frameInfo.contentChecksumFlag = (contentChecksum_t)checksumFlag;
+#if LZ4_VERSION_NUMBER >= 10600
+    prefs.frameInfo.contentSize = (srcFileSize==UTIL_FILESIZE_UNKNOWN) ? 0 : srcFileSize;
+#endif
+    assert(LZ4F_compressBound(blockSize, &prefs) <= ress->dstBufferSize);
+
+    {
+        size_t readSize;
+        size_t headerSize = LZ4F_compressBegin(ctx, ress->dstBuffer, ress->dstBufferSize, &prefs);
+        if (LZ4F_isError(headerSize))
+            EXM_THROW(33, "File header generation failed : %s",
+                            LZ4F_getErrorName(headerSize));
+        if (fwrite(ress->dstBuffer, 1, headerSize, ress->dstFile) != headerSize)
+            EXM_THROW(34, "Write error : %s (cannot write header)", strerror(errno));
+        outFileSize += headerSize;
+
+        /* Read first block */
+        readSize  = fread(ress->srcBuffer, (size_t)1, (size_t)blockSize, ress->srcFile);
+        inFileSize += readSize;
+
+        /* Main Loop */
+        while (readSize>0) {
+            size_t const outSize = LZ4F_compressUpdate(ctx,
+                                        ress->dstBuffer, ress->dstBufferSize,
+                                        ress->srcBuffer, readSize, NULL);
+            if (LZ4F_isError(outSize))
+                EXM_THROW(35, "zstd: %s: lz4 compression failed : %s",
+                            srcFileName, LZ4F_getErrorName(outSize));
+            outFileSize += outSize;
+            if (srcFileSize == UTIL_FILESIZE_UNKNOWN) {
+                DISPLAYUPDATE(2, "\rRead : %u MB ==> %.2f%%",
+                                (unsigned)(inFileSize>>20),
+                                (double)outFileSize/inFileSize*100)
+            } else {
+                DISPLAYUPDATE(2, "\rRead : %u / %u MB ==> %.2f%%",
+                                (unsigned)(inFileSize>>20), (unsigned)(srcFileSize>>20),
+                                (double)outFileSize/inFileSize*100);
+            }
+
+            /* Write Block */
+            {   size_t const sizeCheck = fwrite(ress->dstBuffer, 1, outSize, ress->dstFile);
+                if (sizeCheck != outSize)
+                    EXM_THROW(36, "Write error : %s", strerror(errno));
+            }
+
+            /* Read next block */
+            readSize  = fread(ress->srcBuffer, (size_t)1, (size_t)blockSize, ress->srcFile);
+            inFileSize += readSize;
+        }
+        if (ferror(ress->srcFile)) EXM_THROW(37, "Error reading %s ", srcFileName);
+
+        /* End of Stream mark */
+        headerSize = LZ4F_compressEnd(ctx, ress->dstBuffer, ress->dstBufferSize, NULL);
+        if (LZ4F_isError(headerSize))
+            EXM_THROW(38, "zstd: %s: lz4 end of file generation failed : %s",
+                        srcFileName, LZ4F_getErrorName(headerSize));
+
+        {   size_t const sizeCheck = fwrite(ress->dstBuffer, 1, headerSize, ress->dstFile);
+            if (sizeCheck != headerSize)
+                EXM_THROW(39, "Write error : %s (cannot write end of stream)",
+                            strerror(errno));
+        }
+        outFileSize += headerSize;
+    }
+
+    *readsize = inFileSize;
+    LZ4F_freeCompressionContext(ctx);
+
+    return outFileSize;
+}
+#endif
+
+
+static unsigned long long
+FIO_compressZstdFrame(FIO_prefs_t* const prefs,
+                      const cRess_t* ressPtr,
+                      const char* srcFileName, U64 fileSize,
+                      int compressionLevel, U64* readsize)
+{
+    cRess_t const ress = *ressPtr;
+    FILE* const srcFile = ress.srcFile;
+    FILE* const dstFile = ress.dstFile;
+    U64 compressedfilesize = 0;
+    ZSTD_EndDirective directive = ZSTD_e_continue;
+
+    /* stats */
+    ZSTD_frameProgression previous_zfp_update = { 0, 0, 0, 0, 0, 0 };
+    ZSTD_frameProgression previous_zfp_correction = { 0, 0, 0, 0, 0, 0 };
+    typedef enum { noChange, slower, faster } speedChange_e;
+    speedChange_e speedChange = noChange;
+    unsigned flushWaiting = 0;
+    unsigned inputPresented = 0;
+    unsigned inputBlocked = 0;
+    unsigned lastJobID = 0;
+
+    DISPLAYLEVEL(6, "compression using zstd format \n");
+
+    /* init */
+    if (fileSize != UTIL_FILESIZE_UNKNOWN) {
+        CHECK(ZSTD_CCtx_setPledgedSrcSize(ress.cctx, fileSize));
+    } else if (prefs->streamSrcSize > 0) {
+      /* unknown source size; use the declared stream size */
+      CHECK( ZSTD_CCtx_setPledgedSrcSize(ress.cctx, prefs->streamSrcSize) );
+    }
+    (void)srcFileName;
+
+    /* Main compression loop */
+    do {
+        size_t stillToFlush;
+        /* Fill input Buffer */
+        size_t const inSize = fread(ress.srcBuffer, (size_t)1, ress.srcBufferSize, srcFile);
+        ZSTD_inBuffer inBuff = { ress.srcBuffer, inSize, 0 };
+        DISPLAYLEVEL(6, "fread %u bytes from source \n", (unsigned)inSize);
+        *readsize += inSize;
+
+        if ((inSize == 0) || (*readsize == fileSize))
+            directive = ZSTD_e_end;
+
+        stillToFlush = 1;
+        while ((inBuff.pos != inBuff.size)   /* input buffer must be entirely ingested */
+            || (directive == ZSTD_e_end && stillToFlush != 0) ) {
+
+            size_t const oldIPos = inBuff.pos;
+            ZSTD_outBuffer outBuff = { ress.dstBuffer, ress.dstBufferSize, 0 };
+            size_t const toFlushNow = ZSTD_toFlushNow(ress.cctx);
+            CHECK_V(stillToFlush, ZSTD_compressStream2(ress.cctx, &outBuff, &inBuff, directive));
+
+            /* count stats */
+            inputPresented++;
+            if (oldIPos == inBuff.pos) inputBlocked++;  /* input buffer is full and can't take any more : input speed is faster than consumption rate */
+            if (!toFlushNow) flushWaiting = 1;
+
+            /* Write compressed stream */
+            DISPLAYLEVEL(6, "ZSTD_compress_generic(end:%u) => input pos(%u)<=(%u)size ; output generated %u bytes \n",
+                            (unsigned)directive, (unsigned)inBuff.pos, (unsigned)inBuff.size, (unsigned)outBuff.pos);
+            if (outBuff.pos) {
+                size_t const sizeCheck = fwrite(ress.dstBuffer, 1, outBuff.pos, dstFile);
+                if (sizeCheck != outBuff.pos)
+                    EXM_THROW(25, "Write error : %s (cannot write compressed block)",
+                                    strerror(errno));
+                compressedfilesize += outBuff.pos;
+            }
+
+            /* display notification; and adapt compression level */
+            if (READY_FOR_UPDATE()) {
+                ZSTD_frameProgression const zfp = ZSTD_getFrameProgression(ress.cctx);
+                double const cShare = (double)zfp.produced / (zfp.consumed + !zfp.consumed/*avoid div0*/) * 100;
+
+                /* display progress notifications */
+                if (g_display_prefs.displayLevel >= 3) {
+                    DISPLAYUPDATE(3, "\r(L%i) Buffered :%4u MB - Consumed :%4u MB - Compressed :%4u MB => %.2f%% ",
+                                compressionLevel,
+                                (unsigned)((zfp.ingested - zfp.consumed) >> 20),
+                                (unsigned)(zfp.consumed >> 20),
+                                (unsigned)(zfp.produced >> 20),
+                                cShare );
+                } else {   /* summarized notifications if == 2; */
+                    DISPLAYLEVEL(2, "\rRead : %u ", (unsigned)(zfp.consumed >> 20));
+                    if (fileSize != UTIL_FILESIZE_UNKNOWN)
+                        DISPLAYLEVEL(2, "/ %u ", (unsigned)(fileSize >> 20));
+                    DISPLAYLEVEL(2, "MB ==> %2.f%% ", cShare);
+                    DELAY_NEXT_UPDATE();
+                }
+
+                /* adaptive mode : statistics measurement and speed correction */
+                if (prefs->adaptiveMode) {
+
+                    /* check output speed */
+                    if (zfp.currentJobID > 1) {  /* only possible if nbWorkers >= 1 */
+
+                        unsigned long long newlyProduced = zfp.produced - previous_zfp_update.produced;
+                        unsigned long long newlyFlushed = zfp.flushed - previous_zfp_update.flushed;
+                        assert(zfp.produced >= previous_zfp_update.produced);
+                        assert(prefs->nbWorkers >= 1);
+
+                        /* test if compression is blocked
+                         * either because output is slow and all buffers are full
+                         * or because input is slow and no job can start while waiting for at least one buffer to be filled.
+                         * note : exclude starting part, since currentJobID > 1 */
+                        if ( (zfp.consumed == previous_zfp_update.consumed)   /* no data compressed : no data available, or no more buffer to compress to, OR compression is really slow (compression of a single block is slower than update rate)*/
+                          && (zfp.nbActiveWorkers == 0)                       /* confirmed : no compression ongoing */
+                          ) {
+                            DISPLAYLEVEL(6, "all buffers full : compression stopped => slow down \n")
+                            speedChange = slower;
+                        }
+
+                        previous_zfp_update = zfp;
+
+                        if ( (newlyProduced > (newlyFlushed * 9 / 8))   /* compression produces more data than output can flush (though production can be spiky, due to work unit : (N==4)*block sizes) */
+                          && (flushWaiting == 0)                        /* flush speed was never slowed by lack of production, so it's operating at max capacity */
+                          ) {
+                            DISPLAYLEVEL(6, "compression faster than flush (%llu > %llu), and flushed was never slowed down by lack of production => slow down \n", newlyProduced, newlyFlushed);
+                            speedChange = slower;
+                        }
+                        flushWaiting = 0;
+                    }
+
+                    /* course correct only if there is at least one new job completed */
+                    if (zfp.currentJobID > lastJobID) {
+                        DISPLAYLEVEL(6, "compression level adaptation check \n")
+
+                        /* check input speed */
+                        if (zfp.currentJobID > (unsigned)(prefs->nbWorkers+1)) {   /* warm up period, to fill all workers */
+                            if (inputBlocked <= 0) {
+                                DISPLAYLEVEL(6, "input is never blocked => input is slower than ingestion \n");
+                                speedChange = slower;
+                            } else if (speedChange == noChange) {
+                                unsigned long long newlyIngested = zfp.ingested - previous_zfp_correction.ingested;
+                                unsigned long long newlyConsumed = zfp.consumed - previous_zfp_correction.consumed;
+                                unsigned long long newlyProduced = zfp.produced - previous_zfp_correction.produced;
+                                unsigned long long newlyFlushed  = zfp.flushed  - previous_zfp_correction.flushed;
+                                previous_zfp_correction = zfp;
+                                assert(inputPresented > 0);
+                                DISPLAYLEVEL(6, "input blocked %u/%u(%.2f) - ingested:%u vs %u:consumed - flushed:%u vs %u:produced \n",
+                                                inputBlocked, inputPresented, (double)inputBlocked/inputPresented*100,
+                                                (unsigned)newlyIngested, (unsigned)newlyConsumed,
+                                                (unsigned)newlyFlushed, (unsigned)newlyProduced);
+                                if ( (inputBlocked > inputPresented / 8)     /* input is waiting often, because input buffers is full : compression or output too slow */
+                                  && (newlyFlushed * 33 / 32 > newlyProduced)  /* flush everything that is produced */
+                                  && (newlyIngested * 33 / 32 > newlyConsumed) /* input speed as fast or faster than compression speed */
+                                ) {
+                                    DISPLAYLEVEL(6, "recommend faster as in(%llu) >= (%llu)comp(%llu) <= out(%llu) \n",
+                                                    newlyIngested, newlyConsumed, newlyProduced, newlyFlushed);
+                                    speedChange = faster;
+                                }
+                            }
+                            inputBlocked = 0;
+                            inputPresented = 0;
+                        }
+
+                        if (speedChange == slower) {
+                            DISPLAYLEVEL(6, "slower speed , higher compression \n")
+                            compressionLevel ++;
+                            if (compressionLevel > ZSTD_maxCLevel()) compressionLevel = ZSTD_maxCLevel();
+                            if (compressionLevel > prefs->maxAdaptLevel) compressionLevel = prefs->maxAdaptLevel;
+                            compressionLevel += (compressionLevel == 0);   /* skip 0 */
+                            ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_compressionLevel, compressionLevel);
+                        }
+                        if (speedChange == faster) {
+                            DISPLAYLEVEL(6, "faster speed , lighter compression \n")
+                            compressionLevel --;
+                            if (compressionLevel < prefs->minAdaptLevel) compressionLevel = prefs->minAdaptLevel;
+                            compressionLevel -= (compressionLevel == 0);   /* skip 0 */
+                            ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_compressionLevel, compressionLevel);
+                        }
+                        speedChange = noChange;
+
+                        lastJobID = zfp.currentJobID;
+                    }  /* if (zfp.currentJobID > lastJobID) */
+                }  /* if (g_adaptiveMode) */
+            }  /* if (READY_FOR_UPDATE()) */
+        }  /* while ((inBuff.pos != inBuff.size) */
+    } while (directive != ZSTD_e_end);
+
+    if (ferror(srcFile)) {
+        EXM_THROW(26, "Read error : I/O error");
+    }
+    if (fileSize != UTIL_FILESIZE_UNKNOWN && *readsize != fileSize) {
+        EXM_THROW(27, "Read error : Incomplete read : %llu / %llu B",
+                (unsigned long long)*readsize, (unsigned long long)fileSize);
+    }
+
+    return compressedfilesize;
+}
+
+/*! FIO_compressFilename_internal() :
+ *  same as FIO_compressFilename_extRess(), with `ress.desFile` already opened.
+ *  @return : 0 : compression completed correctly,
+ *            1 : missing or pb opening srcFileName
+ */
+static int
+FIO_compressFilename_internal(FIO_prefs_t* const prefs,
+                              cRess_t ress,
+                              const char* dstFileName, const char* srcFileName,
+                              int compressionLevel)
+{
+    UTIL_time_t const timeStart = UTIL_getTime();
+    clock_t const cpuStart = clock();
+    U64 readsize = 0;
+    U64 compressedfilesize = 0;
+    U64 const fileSize = UTIL_getFileSize(srcFileName);
+    DISPLAYLEVEL(5, "%s: %u bytes \n", srcFileName, (unsigned)fileSize);
+
+    /* compression format selection */
+    switch (prefs->compressionType) {
+        default:
+        case FIO_zstdCompression:
+            compressedfilesize = FIO_compressZstdFrame(prefs, &ress, srcFileName, fileSize, compressionLevel, &readsize);
+            break;
+
+        case FIO_gzipCompression:
+#ifdef ZSTD_GZCOMPRESS
+            compressedfilesize = FIO_compressGzFrame(&ress, srcFileName, fileSize, compressionLevel, &readsize);
+#else
+            (void)compressionLevel;
+            EXM_THROW(20, "zstd: %s: file cannot be compressed as gzip (zstd compiled without ZSTD_GZCOMPRESS) -- ignored \n",
+                            srcFileName);
+#endif
+            break;
+
+        case FIO_xzCompression:
+        case FIO_lzmaCompression:
+#ifdef ZSTD_LZMACOMPRESS
+            compressedfilesize = FIO_compressLzmaFrame(&ress, srcFileName, fileSize, compressionLevel, &readsize, prefs->compressionType==FIO_lzmaCompression);
+#else
+            (void)compressionLevel;
+            EXM_THROW(20, "zstd: %s: file cannot be compressed as xz/lzma (zstd compiled without ZSTD_LZMACOMPRESS) -- ignored \n",
+                            srcFileName);
+#endif
+            break;
+
+        case FIO_lz4Compression:
+#ifdef ZSTD_LZ4COMPRESS
+            compressedfilesize = FIO_compressLz4Frame(&ress, srcFileName, fileSize, compressionLevel, prefs->checksumFlag, &readsize);
+#else
+            (void)compressionLevel;
+            EXM_THROW(20, "zstd: %s: file cannot be compressed as lz4 (zstd compiled without ZSTD_LZ4COMPRESS) -- ignored \n",
+                            srcFileName);
+#endif
+            break;
+    }
+
+    /* Status */
+    DISPLAYLEVEL(2, "\r%79s\r", "");
+    if (readsize == 0) {
+        DISPLAYLEVEL(2,"%-20s :  (%6llu => %6llu bytes, %s) \n",
+            srcFileName,
+            (unsigned long long)readsize, (unsigned long long) compressedfilesize,
+            dstFileName);
+    } else {
+        DISPLAYLEVEL(2,"%-20s :%6.2f%%   (%6llu => %6llu bytes, %s) \n",
+            srcFileName,
+            (double)compressedfilesize / readsize * 100,
+            (unsigned long long)readsize, (unsigned long long) compressedfilesize,
+            dstFileName);
+    }
+
+    /* Elapsed Time and CPU Load */
+    {   clock_t const cpuEnd = clock();
+        double const cpuLoad_s = (double)(cpuEnd - cpuStart) / CLOCKS_PER_SEC;
+        U64 const timeLength_ns = UTIL_clockSpanNano(timeStart);
+        double const timeLength_s = (double)timeLength_ns / 1000000000;
+        double const cpuLoad_pct = (cpuLoad_s / timeLength_s) * 100;
+        DISPLAYLEVEL(4, "%-20s : Completed in %.2f sec  (cpu load : %.0f%%)\n",
+                        srcFileName, timeLength_s, cpuLoad_pct);
+    }
+    return 0;
+}
+
+
+/*! FIO_compressFilename_dstFile() :
+ *  open dstFileName, or pass-through if ress.dstFile != NULL,
+ *  then start compression with FIO_compressFilename_internal().
+ *  Manages source removal (--rm) and file permissions transfer.
+ *  note : ress.srcFile must be != NULL,
+ *  so reach this function through FIO_compressFilename_srcFile().
+ *  @return : 0 : compression completed correctly,
+ *            1 : pb
+ */
+static int FIO_compressFilename_dstFile(FIO_prefs_t* const prefs,
+                                        cRess_t ress,
+                                        const char* dstFileName,
+                                        const char* srcFileName,
+                                        int compressionLevel)
+{
+    int closeDstFile = 0;
+    int result;
+    stat_t statbuf;
+    int transfer_permissions = 0;
+    assert(ress.srcFile != NULL);
+    if (ress.dstFile == NULL) {
+        closeDstFile = 1;
+        DISPLAYLEVEL(6, "FIO_compressFilename_dstFile: opening dst: %s \n", dstFileName);
+        ress.dstFile = FIO_openDstFile(prefs, srcFileName, dstFileName);
+        if (ress.dstFile==NULL) return 1;  /* could not open dstFileName */
+        /* Must only be added after FIO_openDstFile() succeeds.
+         * Otherwise we may delete the destination file if it already exists,
+         * and the user presses Ctrl-C when asked if they wish to overwrite.
+         */
+        addHandler(dstFileName);
+
+        if ( strcmp (srcFileName, stdinmark)
+          && UTIL_getFileStat(srcFileName, &statbuf))
+            transfer_permissions = 1;
+    }
+
+    result = FIO_compressFilename_internal(prefs, ress, dstFileName, srcFileName, compressionLevel);
+
+    if (closeDstFile) {
+        FILE* const dstFile = ress.dstFile;
+        ress.dstFile = NULL;
+
+        clearHandler();
+
+        DISPLAYLEVEL(6, "FIO_compressFilename_dstFile: closing dst: %s \n", dstFileName);
+        if (fclose(dstFile)) { /* error closing dstFile */
+            DISPLAYLEVEL(1, "zstd: %s: %s \n", dstFileName, strerror(errno));
+            result=1;
+        }
+        if ( (result != 0)  /* operation failure */
+          && strcmp(dstFileName, nulmark)     /* special case : don't remove() /dev/null */
+          && strcmp(dstFileName, stdoutmark)  /* special case : don't remove() stdout */
+          ) {
+            FIO_remove(dstFileName); /* remove compression artefact; note don't do anything special if remove() fails */
+        } else if ( strcmp(dstFileName, stdoutmark)
+                 && strcmp(dstFileName, nulmark)
+                 && transfer_permissions) {
+            DISPLAYLEVEL(6, "FIO_compressFilename_dstFile: transfering permissions into dst: %s \n", dstFileName);
+            UTIL_setFileStat(dstFileName, &statbuf);
+        } else {
+            DISPLAYLEVEL(6, "FIO_compressFilename_dstFile: do not transfer permissions into dst: %s \n", dstFileName);
+        }
+    }
+
+    return result;
+}
+
+/* List used to compare file extensions (used with --exclude-compressed flag)
+* Different from the suffixList and should only apply to ZSTD compress operationResult
+*/
+static const char *compressedFileExtensions[] = {
+    ZSTD_EXTENSION,
+    TZSTD_EXTENSION,
+    GZ_EXTENSION,
+    TGZ_EXTENSION,
+    LZMA_EXTENSION,
+    XZ_EXTENSION,
+    TXZ_EXTENSION,
+    LZ4_EXTENSION,
+    TLZ4_EXTENSION,
+    NULL
+};
+
+/*! FIO_compressFilename_srcFile() :
+ *  @return : 0 : compression completed correctly,
+ *            1 : missing or pb opening srcFileName
+ */
+static int
+FIO_compressFilename_srcFile(FIO_prefs_t* const prefs,
+                             cRess_t ress,
+                             const char* dstFileName,
+                             const char* srcFileName,
+                             int compressionLevel)
+{
+    int result;
+    DISPLAYLEVEL(6, "FIO_compressFilename_srcFile: %s \n", srcFileName);
+
+    /* ensure src is not a directory */
+    if (UTIL_isDirectory(srcFileName)) {
+        DISPLAYLEVEL(1, "zstd: %s is a directory -- ignored \n", srcFileName);
+        return 1;
+    }
+
+    /* ensure src is not the same as dict (if present) */
+    if (ress.dictFileName != NULL && UTIL_isSameFile(srcFileName, ress.dictFileName)) {
+        DISPLAYLEVEL(1, "zstd: cannot use %s as an input file and dictionary \n", srcFileName);
+        return 1;
+    }
+
+    /* Check if "srcFile" is compressed. Only done if --exclude-compressed flag is used
+    * YES => ZSTD will skip compression of the file and will return 0.
+    * NO => ZSTD will resume with compress operation.
+    */
+    if (prefs->excludeCompressedFiles == 1 && UTIL_isCompressedFile(srcFileName, compressedFileExtensions)) {
+        DISPLAYLEVEL(4, "File is already compressed : %s \n", srcFileName);
+        return 0;
+    }
+
+    ress.srcFile = FIO_openSrcFile(srcFileName);
+    if (ress.srcFile == NULL) return 1;   /* srcFile could not be opened */
+
+    result = FIO_compressFilename_dstFile(prefs, ress, dstFileName, srcFileName, compressionLevel);
+
+    fclose(ress.srcFile);
+    ress.srcFile = NULL;
+    if ( prefs->removeSrcFile   /* --rm */
+      && result == 0       /* success */
+      && strcmp(srcFileName, stdinmark)   /* exception : don't erase stdin */
+      ) {
+        /* We must clear the handler, since after this point calling it would
+         * delete both the source and destination files.
+         */
+        clearHandler();
+        if (FIO_remove(srcFileName))
+            EXM_THROW(1, "zstd: %s: %s", srcFileName, strerror(errno));
+    }
+    return result;
+}
+
+int FIO_compressFilename(FIO_prefs_t* const prefs, const char* dstFileName,
+                         const char* srcFileName, const char* dictFileName,
+                         int compressionLevel, ZSTD_compressionParameters comprParams)
+{
+    cRess_t const ress = FIO_createCResources(prefs, dictFileName, UTIL_getFileSize(srcFileName), compressionLevel, comprParams);
+    int const result = FIO_compressFilename_srcFile(prefs, ress, dstFileName, srcFileName, compressionLevel);
+
+
+    FIO_freeCResources(ress);
+    return result;
+}
+
+/* FIO_determineCompressedName() :
+ * create a destination filename for compressed srcFileName.
+ * @return a pointer to it.
+ * This function never returns an error (it may abort() in case of pb)
+ */
+static const char*
+FIO_determineCompressedName(const char* srcFileName, const char* outDirName, const char* suffix)
+{
+    static size_t dfnbCapacity = 0;
+    static char* dstFileNameBuffer = NULL;   /* using static allocation : this function cannot be multi-threaded */
+    char* outDirFilename = NULL;
+    size_t sfnSize = strlen(srcFileName);
+    size_t const srcSuffixLen = strlen(suffix);
+    if (outDirName) {
+        outDirFilename = FIO_createFilename_fromOutDir(srcFileName, outDirName, srcSuffixLen);
+        sfnSize = strlen(outDirFilename);
+        assert(outDirFilename != NULL);
+    }
+
+    if (dfnbCapacity <= sfnSize+srcSuffixLen+1) {
+        /* resize buffer for dstName */
+        free(dstFileNameBuffer);
+        dfnbCapacity = sfnSize + srcSuffixLen + 30;
+        dstFileNameBuffer = (char*)malloc(dfnbCapacity);
+        if (!dstFileNameBuffer) {
+            EXM_THROW(30, "zstd: %s", strerror(errno));
+        }
+    }
+    assert(dstFileNameBuffer != NULL);
+
+    if (outDirFilename) {
+        memcpy(dstFileNameBuffer, outDirFilename, sfnSize);
+        free(outDirFilename);
+    } else {
+        memcpy(dstFileNameBuffer, srcFileName, sfnSize);
+    }
+    memcpy(dstFileNameBuffer+sfnSize, suffix, srcSuffixLen+1 /* Include terminating null */);
+    return dstFileNameBuffer;
+}
+
+static unsigned long long FIO_getLargestFileSize(const char** inFileNames, unsigned nbFiles)
+{
+    size_t i;
+    unsigned long long fileSize, maxFileSize = 0;
+    for (i = 0; i < nbFiles; i++) {
+        fileSize = UTIL_getFileSize(inFileNames[i]);
+        maxFileSize = fileSize > maxFileSize ? fileSize : maxFileSize;
+    }
+    return maxFileSize;
+}
+
+/* FIO_compressMultipleFilenames() :
+ * compress nbFiles files
+ * into either one destination (outFileName),
+ * or into one file each (outFileName == NULL, but suffix != NULL),
+ * or into a destination folder (specified with -O)
+ */
+int FIO_compressMultipleFilenames(FIO_prefs_t* const prefs,
+                                  const char** inFileNamesTable, unsigned nbFiles,
+                                  const char* outDirName,
+                                  const char* outFileName, const char* suffix,
+                                  const char* dictFileName, int compressionLevel,
+                                  ZSTD_compressionParameters comprParams)
+{
+    int error = 0;
+    cRess_t ress = FIO_createCResources(prefs, dictFileName,
+        FIO_getLargestFileSize(inFileNamesTable, nbFiles),
+        compressionLevel, comprParams);
+
+    /* init */
+    assert(outFileName != NULL || suffix != NULL);
+    if (outFileName != NULL) {   /* output into a single destination (stdout typically) */
+        ress.dstFile = FIO_openDstFile(prefs, NULL, outFileName);
+        if (ress.dstFile == NULL) {  /* could not open outFileName */
+            error = 1;
+        } else {
+            unsigned u;
+            for (u=0; u<nbFiles; u++)
+                error |= FIO_compressFilename_srcFile(prefs, ress, outFileName, inFileNamesTable[u], compressionLevel);
+            if (fclose(ress.dstFile))
+                EXM_THROW(29, "Write error (%s) : cannot properly close %s",
+                            strerror(errno), outFileName);
+            ress.dstFile = NULL;
+        }
+    } else {
+        unsigned u;
+        for (u=0; u<nbFiles; u++) {
+            const char* const srcFileName = inFileNamesTable[u];
+            const char* const dstFileName = FIO_determineCompressedName(srcFileName, outDirName, suffix);  /* cannot fail */
+            error |= FIO_compressFilename_srcFile(prefs, ress, dstFileName, srcFileName, compressionLevel);
+        }
+        if (outDirName)
+            FIO_checkFilenameCollisions(inFileNamesTable ,nbFiles);
+    }
+
+    FIO_freeCResources(ress);
+    return error;
+}
+
+#endif /* #ifndef ZSTD_NOCOMPRESS */
+
+
+
+#ifndef ZSTD_NODECOMPRESS
+
+/* **************************************************************************
+ *  Decompression
+ ***************************************************************************/
+typedef struct {
+    void*  srcBuffer;
+    size_t srcBufferSize;
+    size_t srcBufferLoaded;
+    void*  dstBuffer;
+    size_t dstBufferSize;
+    ZSTD_DStream* dctx;
+    FILE*  dstFile;
+} dRess_t;
+
+static dRess_t FIO_createDResources(FIO_prefs_t* const prefs, const char* dictFileName)
+{
+    dRess_t ress;
+    memset(&ress, 0, sizeof(ress));
+
+    if (prefs->patchFromMode)
+        FIO_adjustMemLimitForPatchFromMode(prefs, UTIL_getFileSize(dictFileName), 0 /* just use the dict size */);
+
+    /* Allocation */
+    ress.dctx = ZSTD_createDStream();
+    if (ress.dctx==NULL)
+        EXM_THROW(60, "Error: %s : can't create ZSTD_DStream", strerror(errno));
+    CHECK( ZSTD_DCtx_setMaxWindowSize(ress.dctx, prefs->memLimit) );
+    ress.srcBufferSize = ZSTD_DStreamInSize();
+    ress.srcBuffer = malloc(ress.srcBufferSize);
+    ress.dstBufferSize = ZSTD_DStreamOutSize();
+    ress.dstBuffer = malloc(ress.dstBufferSize);
+    if (!ress.srcBuffer || !ress.dstBuffer)
+        EXM_THROW(61, "Allocation error : not enough memory");
+
+    /* dictionary */
+    {   void* dictBuffer;
+        size_t const dictBufferSize = FIO_createDictBuffer(&dictBuffer, dictFileName, prefs);
+        CHECK( ZSTD_initDStream_usingDict(ress.dctx, dictBuffer, dictBufferSize) );
+        free(dictBuffer);
+    }
+
+    return ress;
+}
+
+static void FIO_freeDResources(dRess_t ress)
+{
+    CHECK( ZSTD_freeDStream(ress.dctx) );
+    free(ress.srcBuffer);
+    free(ress.dstBuffer);
+}
+
+
+/** FIO_fwriteSparse() :
+*  @return : storedSkips,
+*            argument for next call to FIO_fwriteSparse() or FIO_fwriteSparseEnd() */
+static unsigned
+FIO_fwriteSparse(FILE* file,
+                 const void* buffer, size_t bufferSize,
+                 const FIO_prefs_t* const prefs,
+                 unsigned storedSkips)
+{
+    const size_t* const bufferT = (const size_t*)buffer;   /* Buffer is supposed malloc'ed, hence aligned on size_t */
+    size_t bufferSizeT = bufferSize / sizeof(size_t);
+    const size_t* const bufferTEnd = bufferT + bufferSizeT;
+    const size_t* ptrT = bufferT;
+    static const size_t segmentSizeT = (32 KB) / sizeof(size_t);   /* check every 32 KB */
+
+    if (prefs->testMode) return 0;  /* do not output anything in test mode */
+
+    if (!prefs->sparseFileSupport) {  /* normal write */
+        size_t const sizeCheck = fwrite(buffer, 1, bufferSize, file);
+        if (sizeCheck != bufferSize)
+            EXM_THROW(70, "Write error : cannot write decoded block : %s",
+                            strerror(errno));
+        return 0;
+    }
+
+    /* avoid int overflow */
+    if (storedSkips > 1 GB) {
+        if (LONG_SEEK(file, 1 GB, SEEK_CUR) != 0)
+            EXM_THROW(91, "1 GB skip error (sparse file support)");
+        storedSkips -= 1 GB;
+    }
+
+    while (ptrT < bufferTEnd) {
+        size_t nb0T;
+
+        /* adjust last segment if < 32 KB */
+        size_t seg0SizeT = segmentSizeT;
+        if (seg0SizeT > bufferSizeT) seg0SizeT = bufferSizeT;
+        bufferSizeT -= seg0SizeT;
+
+        /* count leading zeroes */
+        for (nb0T=0; (nb0T < seg0SizeT) && (ptrT[nb0T] == 0); nb0T++) ;
+        storedSkips += (unsigned)(nb0T * sizeof(size_t));
+
+        if (nb0T != seg0SizeT) {   /* not all 0s */
+            size_t const nbNon0ST = seg0SizeT - nb0T;
+            /* skip leading zeros */
+            if (LONG_SEEK(file, storedSkips, SEEK_CUR) != 0)
+                EXM_THROW(92, "Sparse skip error ; try --no-sparse");
+            storedSkips = 0;
+            /* write the rest */
+            if (fwrite(ptrT + nb0T, sizeof(size_t), nbNon0ST, file) != nbNon0ST)
+                EXM_THROW(93, "Write error : cannot write decoded block : %s",
+                            strerror(errno));
+        }
+        ptrT += seg0SizeT;
+    }
+
+    {   static size_t const maskT = sizeof(size_t)-1;
+        if (bufferSize & maskT) {
+            /* size not multiple of sizeof(size_t) : implies end of block */
+            const char* const restStart = (const char*)bufferTEnd;
+            const char* restPtr = restStart;
+            const char* const restEnd = (const char*)buffer + bufferSize;
+            assert(restEnd > restStart && restEnd < restStart + sizeof(size_t));
+            for ( ; (restPtr < restEnd) && (*restPtr == 0); restPtr++) ;
+            storedSkips += (unsigned) (restPtr - restStart);
+            if (restPtr != restEnd) {
+                /* not all remaining bytes are 0 */
+                size_t const restSize = (size_t)(restEnd - restPtr);
+                if (LONG_SEEK(file, storedSkips, SEEK_CUR) != 0)
+                    EXM_THROW(92, "Sparse skip error ; try --no-sparse");
+                if (fwrite(restPtr, 1, restSize, file) != restSize)
+                    EXM_THROW(95, "Write error : cannot write end of decoded block : %s",
+                        strerror(errno));
+                storedSkips = 0;
+    }   }   }
+
+    return storedSkips;
+}
+
+static void
+FIO_fwriteSparseEnd(const FIO_prefs_t* const prefs, FILE* file, unsigned storedSkips)
+{
+    if (prefs->testMode) assert(storedSkips == 0);
+    if (storedSkips>0) {
+        assert(prefs->sparseFileSupport > 0);  /* storedSkips>0 implies sparse support is enabled */
+        (void)prefs;   /* assert can be disabled, in which case prefs becomes unused */
+        if (LONG_SEEK(file, storedSkips-1, SEEK_CUR) != 0)
+            EXM_THROW(69, "Final skip error (sparse file support)");
+        /* last zero must be explicitly written,
+         * so that skipped ones get implicitly translated as zero by FS */
+        {   const char lastZeroByte[1] = { 0 };
+            if (fwrite(lastZeroByte, 1, 1, file) != 1)
+                EXM_THROW(69, "Write error : cannot write last zero : %s", strerror(errno));
+    }   }
+}
+
+
+/** FIO_passThrough() : just copy input into output, for compatibility with gzip -df mode
+    @return : 0 (no error) */
+static int FIO_passThrough(const FIO_prefs_t* const prefs,
+                           FILE* foutput, FILE* finput,
+                           void* buffer, size_t bufferSize,
+                           size_t alreadyLoaded)
+{
+    size_t const blockSize = MIN(64 KB, bufferSize);
+    size_t readFromInput;
+    unsigned storedSkips = 0;
+
+    /* assumption : ress->srcBufferLoaded bytes already loaded and stored within buffer */
+    {   size_t const sizeCheck = fwrite(buffer, 1, alreadyLoaded, foutput);
+        if (sizeCheck != alreadyLoaded) {
+            DISPLAYLEVEL(1, "Pass-through write error : %s\n", strerror(errno));
+            return 1;
+    }   }
+
+    do {
+        readFromInput = fread(buffer, 1, blockSize, finput);
+        storedSkips = FIO_fwriteSparse(foutput, buffer, readFromInput, prefs, storedSkips);
+    } while (readFromInput == blockSize);
+    if (ferror(finput)) {
+        DISPLAYLEVEL(1, "Pass-through read error : %s\n", strerror(errno));
+        return 1;
+    }
+    assert(feof(finput));
+
+    FIO_fwriteSparseEnd(prefs, foutput, storedSkips);
+    return 0;
+}
+
+/* FIO_zstdErrorHelp() :
+ * detailed error message when requested window size is too large */
+static void
+FIO_zstdErrorHelp(const FIO_prefs_t* const prefs,
+                  const dRess_t* ress,
+                  size_t err, const char* srcFileName)
+{
+    ZSTD_frameHeader header;
+
+    /* Help message only for one specific error */
+    if (ZSTD_getErrorCode(err) != ZSTD_error_frameParameter_windowTooLarge)
+        return;
+
+    /* Try to decode the frame header */
+    err = ZSTD_getFrameHeader(&header, ress->srcBuffer, ress->srcBufferLoaded);
+    if (err == 0) {
+        unsigned long long const windowSize = header.windowSize;
+        unsigned const windowLog = FIO_highbit64(windowSize) + ((windowSize & (windowSize - 1)) != 0);
+        assert(prefs->memLimit > 0);
+        DISPLAYLEVEL(1, "%s : Window size larger than maximum : %llu > %u \n",
+                        srcFileName, windowSize, prefs->memLimit);
+        if (windowLog <= ZSTD_WINDOWLOG_MAX) {
+            unsigned const windowMB = (unsigned)((windowSize >> 20) + ((windowSize & ((1 MB) - 1)) != 0));
+            assert(windowSize < (U64)(1ULL << 52));   /* ensure now overflow for windowMB */
+            DISPLAYLEVEL(1, "%s : Use --long=%u or --memory=%uMB \n",
+                            srcFileName, windowLog, windowMB);
+            return;
+    }   }
+    DISPLAYLEVEL(1, "%s : Window log larger than ZSTD_WINDOWLOG_MAX=%u; not supported \n",
+                    srcFileName, ZSTD_WINDOWLOG_MAX);
+}
+
+/** FIO_decompressFrame() :
+ *  @return : size of decoded zstd frame, or an error code
+ */
+#define FIO_ERROR_FRAME_DECODING   ((unsigned long long)(-2))
+static unsigned long long
+FIO_decompressZstdFrame(dRess_t* ress, FILE* finput,
+                        const FIO_prefs_t* const prefs,
+                        const char* srcFileName,
+                        U64 alreadyDecoded)  /* for multi-frames streams */
+{
+    U64 frameSize = 0;
+    U32 storedSkips = 0;
+
+    /* display last 20 characters only */
+    {   size_t const srcFileLength = strlen(srcFileName);
+        if (srcFileLength>20) srcFileName += srcFileLength-20;
+    }
+
+    ZSTD_resetDStream(ress->dctx);
+
+    /* Header loading : ensures ZSTD_getFrameHeader() will succeed */
+    {   size_t const toDecode = ZSTD_FRAMEHEADERSIZE_MAX;
+        if (ress->srcBufferLoaded < toDecode) {
+            size_t const toRead = toDecode - ress->srcBufferLoaded;
+            void* const startPosition = (char*)ress->srcBuffer + ress->srcBufferLoaded;
+            ress->srcBufferLoaded += fread(startPosition, 1, toRead, finput);
+    }   }
+
+    /* Main decompression Loop */
+    while (1) {
+        ZSTD_inBuffer  inBuff = { ress->srcBuffer, ress->srcBufferLoaded, 0 };
+        ZSTD_outBuffer outBuff= { ress->dstBuffer, ress->dstBufferSize, 0 };
+        size_t const readSizeHint = ZSTD_decompressStream(ress->dctx, &outBuff, &inBuff);
+        if (ZSTD_isError(readSizeHint)) {
+            DISPLAYLEVEL(1, "%s : Decoding error (36) : %s \n",
+                            srcFileName, ZSTD_getErrorName(readSizeHint));
+            FIO_zstdErrorHelp(prefs, ress, readSizeHint, srcFileName);
+            return FIO_ERROR_FRAME_DECODING;
+        }
+
+        /* Write block */
+        storedSkips = FIO_fwriteSparse(ress->dstFile, ress->dstBuffer, outBuff.pos, prefs, storedSkips);
+        frameSize += outBuff.pos;
+        DISPLAYUPDATE(2, "\r%-20.20s : %u MB...     ",
+                         srcFileName, (unsigned)((alreadyDecoded+frameSize)>>20) );
+
+        if (inBuff.pos > 0) {
+            memmove(ress->srcBuffer, (char*)ress->srcBuffer + inBuff.pos, inBuff.size - inBuff.pos);
+            ress->srcBufferLoaded -= inBuff.pos;
+        }
+
+        if (readSizeHint == 0) break;   /* end of frame */
+
+        /* Fill input buffer */
+        {   size_t const toDecode = MIN(readSizeHint, ress->srcBufferSize);  /* support large skippable frames */
+            if (ress->srcBufferLoaded < toDecode) {
+                size_t const toRead = toDecode - ress->srcBufferLoaded;   /* > 0 */
+                void* const startPosition = (char*)ress->srcBuffer + ress->srcBufferLoaded;
+                size_t const readSize = fread(startPosition, 1, toRead, finput);
+                if (readSize==0) {
+                    DISPLAYLEVEL(1, "%s : Read error (39) : premature end \n",
+                                    srcFileName);
+                    return FIO_ERROR_FRAME_DECODING;
+                }
+                ress->srcBufferLoaded += readSize;
+    }   }   }
+
+    FIO_fwriteSparseEnd(prefs, ress->dstFile, storedSkips);
+
+    return frameSize;
+}
+
+
+#ifdef ZSTD_GZDECOMPRESS
+static unsigned long long
+FIO_decompressGzFrame(dRess_t* ress, FILE* srcFile,
+                      const FIO_prefs_t* const prefs,
+                      const char* srcFileName)
+{
+    unsigned long long outFileSize = 0;
+    z_stream strm;
+    int flush = Z_NO_FLUSH;
+    int decodingError = 0;
+    unsigned storedSkips = 0;
+
+    strm.zalloc = Z_NULL;
+    strm.zfree = Z_NULL;
+    strm.opaque = Z_NULL;
+    strm.next_in = 0;
+    strm.avail_in = 0;
+    /* see http://www.zlib.net/manual.html */
+    if (inflateInit2(&strm, 15 /* maxWindowLogSize */ + 16 /* gzip only */) != Z_OK)
+        return FIO_ERROR_FRAME_DECODING;
+
+    strm.next_out = (Bytef*)ress->dstBuffer;
+    strm.avail_out = (uInt)ress->dstBufferSize;
+    strm.avail_in = (uInt)ress->srcBufferLoaded;
+    strm.next_in = (z_const unsigned char*)ress->srcBuffer;
+
+    for ( ; ; ) {
+        int ret;
+        if (strm.avail_in == 0) {
+            ress->srcBufferLoaded = fread(ress->srcBuffer, 1, ress->srcBufferSize, srcFile);
+            if (ress->srcBufferLoaded == 0) flush = Z_FINISH;
+            strm.next_in = (z_const unsigned char*)ress->srcBuffer;
+            strm.avail_in = (uInt)ress->srcBufferLoaded;
+        }
+        ret = inflate(&strm, flush);
+        if (ret == Z_BUF_ERROR) {
+            DISPLAYLEVEL(1, "zstd: %s: premature gz end \n", srcFileName);
+            decodingError = 1; break;
+        }
+        if (ret != Z_OK && ret != Z_STREAM_END) {
+            DISPLAYLEVEL(1, "zstd: %s: inflate error %d \n", srcFileName, ret);
+            decodingError = 1; break;
+        }
+        {   size_t const decompBytes = ress->dstBufferSize - strm.avail_out;
+            if (decompBytes) {
+                storedSkips = FIO_fwriteSparse(ress->dstFile, ress->dstBuffer, decompBytes, prefs, storedSkips);
+                outFileSize += decompBytes;
+                strm.next_out = (Bytef*)ress->dstBuffer;
+                strm.avail_out = (uInt)ress->dstBufferSize;
+            }
+        }
+        if (ret == Z_STREAM_END) break;
+    }
+
+    if (strm.avail_in > 0)
+        memmove(ress->srcBuffer, strm.next_in, strm.avail_in);
+    ress->srcBufferLoaded = strm.avail_in;
+    if ( (inflateEnd(&strm) != Z_OK)  /* release resources ; error detected */
+      && (decodingError==0) ) {
+        DISPLAYLEVEL(1, "zstd: %s: inflateEnd error \n", srcFileName);
+        decodingError = 1;
+    }
+    FIO_fwriteSparseEnd(prefs, ress->dstFile, storedSkips);
+    return decodingError ? FIO_ERROR_FRAME_DECODING : outFileSize;
+}
+#endif
+
+
+#ifdef ZSTD_LZMADECOMPRESS
+static unsigned long long
+FIO_decompressLzmaFrame(dRess_t* ress, FILE* srcFile,
+                        const FIO_prefs_t* const prefs,
+                        const char* srcFileName, int plain_lzma)
+{
+    unsigned long long outFileSize = 0;
+    lzma_stream strm = LZMA_STREAM_INIT;
+    lzma_action action = LZMA_RUN;
+    lzma_ret initRet;
+    int decodingError = 0;
+    unsigned storedSkips = 0;
+
+    strm.next_in = 0;
+    strm.avail_in = 0;
+    if (plain_lzma) {
+        initRet = lzma_alone_decoder(&strm, UINT64_MAX); /* LZMA */
+    } else {
+        initRet = lzma_stream_decoder(&strm, UINT64_MAX, 0); /* XZ */
+    }
+
+    if (initRet != LZMA_OK) {
+        DISPLAYLEVEL(1, "zstd: %s: %s error %d \n",
+                        plain_lzma ? "lzma_alone_decoder" : "lzma_stream_decoder",
+                        srcFileName, initRet);
+        return FIO_ERROR_FRAME_DECODING;
+    }
+
+    strm.next_out = (BYTE*)ress->dstBuffer;
+    strm.avail_out = ress->dstBufferSize;
+    strm.next_in = (BYTE const*)ress->srcBuffer;
+    strm.avail_in = ress->srcBufferLoaded;
+
+    for ( ; ; ) {
+        lzma_ret ret;
+        if (strm.avail_in == 0) {
+            ress->srcBufferLoaded = fread(ress->srcBuffer, 1, ress->srcBufferSize, srcFile);
+            if (ress->srcBufferLoaded == 0) action = LZMA_FINISH;
+            strm.next_in = (BYTE const*)ress->srcBuffer;
+            strm.avail_in = ress->srcBufferLoaded;
+        }
+        ret = lzma_code(&strm, action);
+
+        if (ret == LZMA_BUF_ERROR) {
+            DISPLAYLEVEL(1, "zstd: %s: premature lzma end \n", srcFileName);
+            decodingError = 1; break;
+        }
+        if (ret != LZMA_OK && ret != LZMA_STREAM_END) {
+            DISPLAYLEVEL(1, "zstd: %s: lzma_code decoding error %d \n",
+                            srcFileName, ret);
+            decodingError = 1; break;
+        }
+        {   size_t const decompBytes = ress->dstBufferSize - strm.avail_out;
+            if (decompBytes) {
+                storedSkips = FIO_fwriteSparse(ress->dstFile, ress->dstBuffer, decompBytes, prefs, storedSkips);
+                outFileSize += decompBytes;
+                strm.next_out = (BYTE*)ress->dstBuffer;
+                strm.avail_out = ress->dstBufferSize;
+        }   }
+        if (ret == LZMA_STREAM_END) break;
+    }
+
+    if (strm.avail_in > 0)
+        memmove(ress->srcBuffer, strm.next_in, strm.avail_in);
+    ress->srcBufferLoaded = strm.avail_in;
+    lzma_end(&strm);
+    FIO_fwriteSparseEnd(prefs, ress->dstFile, storedSkips);
+    return decodingError ? FIO_ERROR_FRAME_DECODING : outFileSize;
+}
+#endif
+
+#ifdef ZSTD_LZ4DECOMPRESS
+static unsigned long long
+FIO_decompressLz4Frame(dRess_t* ress, FILE* srcFile,
+                       const FIO_prefs_t* const prefs,
+                       const char* srcFileName)
+{
+    unsigned long long filesize = 0;
+    LZ4F_errorCode_t nextToLoad;
+    LZ4F_decompressionContext_t dCtx;
+    LZ4F_errorCode_t const errorCode = LZ4F_createDecompressionContext(&dCtx, LZ4F_VERSION);
+    int decodingError = 0;
+    unsigned storedSkips = 0;
+
+    if (LZ4F_isError(errorCode)) {
+        DISPLAYLEVEL(1, "zstd: failed to create lz4 decompression context \n");
+        return FIO_ERROR_FRAME_DECODING;
+    }
+
+    /* Init feed with magic number (already consumed from FILE* sFile) */
+    {   size_t inSize = 4;
+        size_t outSize= 0;
+        MEM_writeLE32(ress->srcBuffer, LZ4_MAGICNUMBER);
+        nextToLoad = LZ4F_decompress(dCtx, ress->dstBuffer, &outSize, ress->srcBuffer, &inSize, NULL);
+        if (LZ4F_isError(nextToLoad)) {
+            DISPLAYLEVEL(1, "zstd: %s: lz4 header error : %s \n",
+                            srcFileName, LZ4F_getErrorName(nextToLoad));
+            LZ4F_freeDecompressionContext(dCtx);
+            return FIO_ERROR_FRAME_DECODING;
+    }   }
+
+    /* Main Loop */
+    for (;nextToLoad;) {
+        size_t readSize;
+        size_t pos = 0;
+        size_t decodedBytes = ress->dstBufferSize;
+
+        /* Read input */
+        if (nextToLoad > ress->srcBufferSize) nextToLoad = ress->srcBufferSize;
+        readSize = fread(ress->srcBuffer, 1, nextToLoad, srcFile);
+        if (!readSize) break;   /* reached end of file or stream */
+
+        while ((pos < readSize) || (decodedBytes == ress->dstBufferSize)) {  /* still to read, or still to flush */
+            /* Decode Input (at least partially) */
+            size_t remaining = readSize - pos;
+            decodedBytes = ress->dstBufferSize;
+            nextToLoad = LZ4F_decompress(dCtx, ress->dstBuffer, &decodedBytes, (char*)(ress->srcBuffer)+pos, &remaining, NULL);
+            if (LZ4F_isError(nextToLoad)) {
+                DISPLAYLEVEL(1, "zstd: %s: lz4 decompression error : %s \n",
+                                srcFileName, LZ4F_getErrorName(nextToLoad));
+                decodingError = 1; nextToLoad = 0; break;
+            }
+            pos += remaining;
+
+            /* Write Block */
+            if (decodedBytes) {
+                storedSkips = FIO_fwriteSparse(ress->dstFile, ress->dstBuffer, decodedBytes, prefs, storedSkips);
+                filesize += decodedBytes;
+                DISPLAYUPDATE(2, "\rDecompressed : %u MB  ", (unsigned)(filesize>>20));
+            }
+
+            if (!nextToLoad) break;
+        }
+    }
+    /* can be out because readSize == 0, which could be an fread() error */
+    if (ferror(srcFile)) {
+        DISPLAYLEVEL(1, "zstd: %s: read error \n", srcFileName);
+        decodingError=1;
+    }
+
+    if (nextToLoad!=0) {
+        DISPLAYLEVEL(1, "zstd: %s: unfinished lz4 stream \n", srcFileName);
+        decodingError=1;
+    }
+
+    LZ4F_freeDecompressionContext(dCtx);
+    ress->srcBufferLoaded = 0; /* LZ4F will reach exact frame boundary */
+    FIO_fwriteSparseEnd(prefs, ress->dstFile, storedSkips);
+
+    return decodingError ? FIO_ERROR_FRAME_DECODING : filesize;
+}
+#endif
+
+
+
+/** FIO_decompressFrames() :
+ *  Find and decode frames inside srcFile
+ *  srcFile presumed opened and valid
+ * @return : 0 : OK
+ *           1 : error
+ */
+static int FIO_decompressFrames(dRess_t ress, FILE* srcFile,
+                          const FIO_prefs_t* const prefs,
+                          const char* dstFileName, const char* srcFileName)
+{
+    unsigned readSomething = 0;
+    unsigned long long filesize = 0;
+    assert(srcFile != NULL);
+
+    /* for each frame */
+    for ( ; ; ) {
+        /* check magic number -> version */
+        size_t const toRead = 4;
+        const BYTE* const buf = (const BYTE*)ress.srcBuffer;
+        if (ress.srcBufferLoaded < toRead)  /* load up to 4 bytes for header */
+            ress.srcBufferLoaded += fread((char*)ress.srcBuffer + ress.srcBufferLoaded,
+                                          (size_t)1, toRead - ress.srcBufferLoaded, srcFile);
+        if (ress.srcBufferLoaded==0) {
+            if (readSomething==0) {  /* srcFile is empty (which is invalid) */
+                DISPLAYLEVEL(1, "zstd: %s: unexpected end of file \n", srcFileName);
+                return 1;
+            }  /* else, just reached frame boundary */
+            break;   /* no more input */
+        }
+        readSomething = 1;   /* there is at least 1 byte in srcFile */
+        if (ress.srcBufferLoaded < toRead) {
+            DISPLAYLEVEL(1, "zstd: %s: unknown header \n", srcFileName);
+            return 1;
+        }
+        if (ZSTD_isFrame(buf, ress.srcBufferLoaded)) {
+            unsigned long long const frameSize = FIO_decompressZstdFrame(&ress, srcFile, prefs, srcFileName, filesize);
+            if (frameSize == FIO_ERROR_FRAME_DECODING) return 1;
+            filesize += frameSize;
+        } else if (buf[0] == 31 && buf[1] == 139) { /* gz magic number */
+#ifdef ZSTD_GZDECOMPRESS
+            unsigned long long const frameSize = FIO_decompressGzFrame(&ress, srcFile, prefs, srcFileName);
+            if (frameSize == FIO_ERROR_FRAME_DECODING) return 1;
+            filesize += frameSize;
+#else
+            DISPLAYLEVEL(1, "zstd: %s: gzip file cannot be uncompressed (zstd compiled without HAVE_ZLIB) -- ignored \n", srcFileName);
+            return 1;
+#endif
+        } else if ((buf[0] == 0xFD && buf[1] == 0x37)  /* xz magic number */
+                || (buf[0] == 0x5D && buf[1] == 0x00)) { /* lzma header (no magic number) */
+#ifdef ZSTD_LZMADECOMPRESS
+            unsigned long long const frameSize = FIO_decompressLzmaFrame(&ress, srcFile, prefs, srcFileName, buf[0] != 0xFD);
+            if (frameSize == FIO_ERROR_FRAME_DECODING) return 1;
+            filesize += frameSize;
+#else
+            DISPLAYLEVEL(1, "zstd: %s: xz/lzma file cannot be uncompressed (zstd compiled without HAVE_LZMA) -- ignored \n", srcFileName);
+            return 1;
+#endif
+        } else if (MEM_readLE32(buf) == LZ4_MAGICNUMBER) {
+#ifdef ZSTD_LZ4DECOMPRESS
+            unsigned long long const frameSize = FIO_decompressLz4Frame(&ress, srcFile, prefs, srcFileName);
+            if (frameSize == FIO_ERROR_FRAME_DECODING) return 1;
+            filesize += frameSize;
+#else
+            DISPLAYLEVEL(1, "zstd: %s: lz4 file cannot be uncompressed (zstd compiled without HAVE_LZ4) -- ignored \n", srcFileName);
+            return 1;
+#endif
+        } else if ((prefs->overwrite) && !strcmp (dstFileName, stdoutmark)) {  /* pass-through mode */
+            return FIO_passThrough(prefs,
+                                   ress.dstFile, srcFile,
+                                   ress.srcBuffer, ress.srcBufferSize,
+                                   ress.srcBufferLoaded);
+        } else {
+            DISPLAYLEVEL(1, "zstd: %s: unsupported format \n", srcFileName);
+            return 1;
+    }   }  /* for each frame */
+
+    /* Final Status */
+    DISPLAYLEVEL(2, "\r%79s\r", "");
+    DISPLAYLEVEL(2, "%-20s: %llu bytes \n", srcFileName, filesize);
+
+    return 0;
+}
+
+/** FIO_decompressDstFile() :
+    open `dstFileName`,
+    or path-through if ress.dstFile is already != 0,
+    then start decompression process (FIO_decompressFrames()).
+    @return : 0 : OK
+              1 : operation aborted
+*/
+static int FIO_decompressDstFile(FIO_prefs_t* const prefs,
+                                 dRess_t ress, FILE* srcFile,
+                                 const char* dstFileName, const char* srcFileName)
+{
+    int result;
+    stat_t statbuf;
+    int transfer_permissions = 0;
+    int releaseDstFile = 0;
+
+    if ((ress.dstFile == NULL) && (prefs->testMode==0)) {
+        releaseDstFile = 1;
+
+        ress.dstFile = FIO_openDstFile(prefs, srcFileName, dstFileName);
+        if (ress.dstFile==NULL) return 1;
+
+        /* Must only be added after FIO_openDstFile() succeeds.
+         * Otherwise we may delete the destination file if it already exists,
+         * and the user presses Ctrl-C when asked if they wish to overwrite.
+         */
+        addHandler(dstFileName);
+
+        if ( strcmp(srcFileName, stdinmark)   /* special case : don't transfer permissions from stdin */
+          && UTIL_getFileStat(srcFileName, &statbuf) )
+            transfer_permissions = 1;
+    }
+
+    result = FIO_decompressFrames(ress, srcFile, prefs, dstFileName, srcFileName);
+
+    if (releaseDstFile) {
+        FILE* const dstFile = ress.dstFile;
+        clearHandler();
+        ress.dstFile = NULL;
+        if (fclose(dstFile)) {
+            DISPLAYLEVEL(1, "zstd: %s: %s \n", dstFileName, strerror(errno));
+            result = 1;
+        }
+
+        if ( (result != 0)  /* operation failure */
+          && strcmp(dstFileName, nulmark)     /* special case : don't remove() /dev/null (#316) */
+          && strcmp(dstFileName, stdoutmark)  /* special case : don't remove() stdout */
+          ) {
+            FIO_remove(dstFileName);  /* remove decompression artefact; note: don't do anything special if remove() fails */
+        } else {  /* operation success */
+            if ( strcmp(dstFileName, stdoutmark) /* special case : don't chmod stdout */
+              && strcmp(dstFileName, nulmark)    /* special case : don't chmod /dev/null */
+              && transfer_permissions )          /* file permissions correctly extracted from src */
+                UTIL_setFileStat(dstFileName, &statbuf);  /* transfer file permissions from src into dst */
+        }
+    }
+
+    return result;
+}
+
+
+/** FIO_decompressSrcFile() :
+    Open `srcFileName`, transfer control to decompressDstFile()
+    @return : 0 : OK
+              1 : error
+*/
+static int FIO_decompressSrcFile(FIO_prefs_t* const prefs, dRess_t ress, const char* dstFileName, const char* srcFileName)
+{
+    FILE* srcFile;
+    int result;
+
+    if (UTIL_isDirectory(srcFileName)) {
+        DISPLAYLEVEL(1, "zstd: %s is a directory -- ignored \n", srcFileName);
+        return 1;
+    }
+
+    srcFile = FIO_openSrcFile(srcFileName);
+    if (srcFile==NULL) return 1;
+    ress.srcBufferLoaded = 0;
+
+    result = FIO_decompressDstFile(prefs, ress, srcFile, dstFileName, srcFileName);
+
+    /* Close file */
+    if (fclose(srcFile)) {
+        DISPLAYLEVEL(1, "zstd: %s: %s \n", srcFileName, strerror(errno));  /* error should not happen */
+        return 1;
+    }
+    if ( prefs->removeSrcFile  /* --rm */
+      && (result==0)      /* decompression successful */
+      && strcmp(srcFileName, stdinmark) ) /* not stdin */ {
+        /* We must clear the handler, since after this point calling it would
+         * delete both the source and destination files.
+         */
+        clearHandler();
+        if (FIO_remove(srcFileName)) {
+            /* failed to remove src file */
+            DISPLAYLEVEL(1, "zstd: %s: %s \n", srcFileName, strerror(errno));
+            return 1;
+    }   }
+    return result;
+}
+
+
+
+int FIO_decompressFilename(FIO_prefs_t* const prefs,
+                           const char* dstFileName, const char* srcFileName,
+                           const char* dictFileName)
+{
+    dRess_t const ress = FIO_createDResources(prefs, dictFileName);
+
+    int const decodingError = FIO_decompressSrcFile(prefs, ress, dstFileName, srcFileName);
+
+    FIO_freeDResources(ress);
+    return decodingError;
+}
+
+static const char *suffixList[] = {
+    ZSTD_EXTENSION,
+    TZSTD_EXTENSION,
+#ifdef ZSTD_GZDECOMPRESS
+    GZ_EXTENSION,
+    TGZ_EXTENSION,
+#endif
+#ifdef ZSTD_LZMADECOMPRESS
+    LZMA_EXTENSION,
+    XZ_EXTENSION,
+    TXZ_EXTENSION,
+#endif
+#ifdef ZSTD_LZ4DECOMPRESS
+    LZ4_EXTENSION,
+    TLZ4_EXTENSION,
+#endif
+    NULL
+};
+
+static const char *suffixListStr =
+    ZSTD_EXTENSION "/" TZSTD_EXTENSION
+#ifdef ZSTD_GZDECOMPRESS
+    "/" GZ_EXTENSION "/" TGZ_EXTENSION
+#endif
+#ifdef ZSTD_LZMADECOMPRESS
+    "/" LZMA_EXTENSION "/" XZ_EXTENSION "/" TXZ_EXTENSION
+#endif
+#ifdef ZSTD_LZ4DECOMPRESS
+    "/" LZ4_EXTENSION "/" TLZ4_EXTENSION
+#endif
+;
+
+/* FIO_determineDstName() :
+ * create a destination filename from a srcFileName.
+ * @return a pointer to it.
+ * @return == NULL if there is an error */
+static const char*
+FIO_determineDstName(const char* srcFileName, const char* outDirName)
+{
+    static size_t dfnbCapacity = 0;
+    static char* dstFileNameBuffer = NULL;   /* using static allocation : this function cannot be multi-threaded */
+    size_t dstFileNameEndPos;
+    char* outDirFilename = NULL;
+    const char* dstSuffix = "";
+    size_t dstSuffixLen = 0;
+
+    size_t sfnSize = strlen(srcFileName);
+
+    size_t srcSuffixLen;
+    const char* const srcSuffix = strrchr(srcFileName, '.');
+    if (srcSuffix == NULL) {
+        DISPLAYLEVEL(1,
+            "zstd: %s: unknown suffix (%s expected). "
+            "Can't derive the output file name. "
+            "Specify it with -o dstFileName. Ignoring.\n",
+            srcFileName, suffixListStr);
+        return NULL;
+    }
+    srcSuffixLen = strlen(srcSuffix);
+
+    {
+        const char** matchedSuffixPtr;
+        for (matchedSuffixPtr = suffixList; *matchedSuffixPtr != NULL; matchedSuffixPtr++) {
+            if (!strcmp(*matchedSuffixPtr, srcSuffix)) {
+                break;
+            }
+        }
+
+        /* check suffix is authorized */
+        if (sfnSize <= srcSuffixLen || *matchedSuffixPtr == NULL) {
+            DISPLAYLEVEL(1,
+                "zstd: %s: unknown suffix (%s expected). "
+                "Can't derive the output file name. "
+                "Specify it with -o dstFileName. Ignoring.\n",
+                srcFileName, suffixListStr);
+            return NULL;
+        }
+
+        if ((*matchedSuffixPtr)[1] == 't') {
+            dstSuffix = ".tar";
+            dstSuffixLen = strlen(dstSuffix);
+        }
+    }
+
+    if (outDirName) {
+        outDirFilename = FIO_createFilename_fromOutDir(srcFileName, outDirName, 0);
+        sfnSize = strlen(outDirFilename);
+        assert(outDirFilename != NULL);
+    }
+
+    if (dfnbCapacity+srcSuffixLen <= sfnSize+1+dstSuffixLen) {
+        /* allocate enough space to write dstFilename into it */
+        free(dstFileNameBuffer);
+        dfnbCapacity = sfnSize + 20;
+        dstFileNameBuffer = (char*)malloc(dfnbCapacity);
+        if (dstFileNameBuffer==NULL)
+            EXM_THROW(74, "%s : not enough memory for dstFileName",
+                      strerror(errno));
+    }
+
+    /* return dst name == src name truncated from suffix */
+    assert(dstFileNameBuffer != NULL);
+    dstFileNameEndPos = sfnSize - srcSuffixLen;
+    if (outDirFilename) {
+        memcpy(dstFileNameBuffer, outDirFilename, dstFileNameEndPos);
+        free(outDirFilename);
+    } else {
+        memcpy(dstFileNameBuffer, srcFileName, dstFileNameEndPos);
+    }
+
+    /* The short tar extensions tzst, tgz, txz and tlz4 files should have "tar"
+     * extension on decompression. Also writes terminating null. */
+    strcpy(dstFileNameBuffer + dstFileNameEndPos, dstSuffix);
+    return dstFileNameBuffer;
+
+    /* note : dstFileNameBuffer memory is not going to be free */
+}
+
+
+int
+FIO_decompressMultipleFilenames(FIO_prefs_t* const prefs,
+                                const char** srcNamesTable, unsigned nbFiles,
+                                const char* outDirName, const char* outFileName,
+                                const char* dictFileName)
+{
+    int error = 0;
+    dRess_t ress = FIO_createDResources(prefs, dictFileName);
+
+    if (outFileName) {
+        unsigned u;
+        if (!prefs->testMode) {
+            ress.dstFile = FIO_openDstFile(prefs, NULL, outFileName);
+            if (ress.dstFile == 0) EXM_THROW(19, "cannot open %s", outFileName);
+        }
+        for (u=0; u<nbFiles; u++)
+            error |= FIO_decompressSrcFile(prefs, ress, outFileName, srcNamesTable[u]);
+        if ((!prefs->testMode) && (fclose(ress.dstFile)))
+            EXM_THROW(72, "Write error : %s : cannot properly close output file",
+                        strerror(errno));
+    } else {
+        unsigned u;
+        for (u=0; u<nbFiles; u++) {   /* create dstFileName */
+            const char* const srcFileName = srcNamesTable[u];
+            const char* const dstFileName = FIO_determineDstName(srcFileName, outDirName);
+            if (dstFileName == NULL) { error=1; continue; }
+
+            error |= FIO_decompressSrcFile(prefs, ress, dstFileName, srcFileName);
+        }
+        if (outDirName)
+            FIO_checkFilenameCollisions(srcNamesTable ,nbFiles);
+    }
+
+    FIO_freeDResources(ress);
+    return error;
+}
+
+/* **************************************************************************
+ *  .zst file info (--list command)
+ ***************************************************************************/
+
+typedef struct {
+    U64 decompressedSize;
+    U64 compressedSize;
+    U64 windowSize;
+    int numActualFrames;
+    int numSkippableFrames;
+    int decompUnavailable;
+    int usesCheck;
+    U32 nbFiles;
+} fileInfo_t;
+
+typedef enum {
+  info_success=0,
+  info_frame_error=1,
+  info_not_zstd=2,
+  info_file_error=3,
+  info_truncated_input=4,
+} InfoError;
+
+#define ERROR_IF(c,n,...) {             \
+    if (c) {                           \
+        DISPLAYLEVEL(1, __VA_ARGS__);  \
+        DISPLAYLEVEL(1, " \n");        \
+        return n;                      \
+    }                                  \
+}
+
+static InfoError
+FIO_analyzeFrames(fileInfo_t* info, FILE* const srcFile)
+{
+    /* begin analyzing frame */
+    for ( ; ; ) {
+        BYTE headerBuffer[ZSTD_FRAMEHEADERSIZE_MAX];
+        size_t const numBytesRead = fread(headerBuffer, 1, sizeof(headerBuffer), srcFile);
+        if (numBytesRead < ZSTD_FRAMEHEADERSIZE_MIN(ZSTD_f_zstd1)) {
+            if ( feof(srcFile)
+              && (numBytesRead == 0)
+              && (info->compressedSize > 0)
+              && (info->compressedSize != UTIL_FILESIZE_UNKNOWN) ) {
+                unsigned long long file_position = (unsigned long long) LONG_TELL(srcFile);
+                unsigned long long file_size = (unsigned long long) info->compressedSize;
+                ERROR_IF(file_position != file_size, info_truncated_input,
+                  "Error: seeked to position %llu, which is beyond file size of %llu\n",
+                  file_position,
+                  file_size);
+                break;  /* correct end of file => success */
+            }
+            ERROR_IF(feof(srcFile), info_not_zstd, "Error: reached end of file with incomplete frame");
+            ERROR_IF(1, info_frame_error, "Error: did not reach end of file but ran out of frames");
+        }
+        {   U32 const magicNumber = MEM_readLE32(headerBuffer);
+            /* Zstandard frame */
+            if (magicNumber == ZSTD_MAGICNUMBER) {
+                ZSTD_frameHeader header;
+                U64 const frameContentSize = ZSTD_getFrameContentSize(headerBuffer, numBytesRead);
+                if ( frameContentSize == ZSTD_CONTENTSIZE_ERROR
+                  || frameContentSize == ZSTD_CONTENTSIZE_UNKNOWN ) {
+                    info->decompUnavailable = 1;
+                } else {
+                    info->decompressedSize += frameContentSize;
+                }
+                ERROR_IF(ZSTD_getFrameHeader(&header, headerBuffer, numBytesRead) != 0,
+                        info_frame_error, "Error: could not decode frame header");
+                info->windowSize = header.windowSize;
+                /* move to the end of the frame header */
+                {   size_t const headerSize = ZSTD_frameHeaderSize(headerBuffer, numBytesRead);
+                    ERROR_IF(ZSTD_isError(headerSize), info_frame_error, "Error: could not determine frame header size");
+                    ERROR_IF(fseek(srcFile, ((long)headerSize)-((long)numBytesRead), SEEK_CUR) != 0,
+                            info_frame_error, "Error: could not move to end of frame header");
+                }
+
+                /* skip all blocks in the frame */
+                {   int lastBlock = 0;
+                    do {
+                        BYTE blockHeaderBuffer[3];
+                        ERROR_IF(fread(blockHeaderBuffer, 1, 3, srcFile) != 3,
+                                info_frame_error, "Error while reading block header");
+                        {   U32 const blockHeader = MEM_readLE24(blockHeaderBuffer);
+                            U32 const blockTypeID = (blockHeader >> 1) & 3;
+                            U32 const isRLE = (blockTypeID == 1);
+                            U32 const isWrongBlock = (blockTypeID == 3);
+                            long const blockSize = isRLE ? 1 : (long)(blockHeader >> 3);
+                            ERROR_IF(isWrongBlock, info_frame_error, "Error: unsupported block type");
+                            lastBlock = blockHeader & 1;
+                            ERROR_IF(fseek(srcFile, blockSize, SEEK_CUR) != 0,
+                                    info_frame_error, "Error: could not skip to end of block");
+                        }
+                    } while (lastBlock != 1);
+                }
+
+                /* check if checksum is used */
+                {   BYTE const frameHeaderDescriptor = headerBuffer[4];
+                    int const contentChecksumFlag = (frameHeaderDescriptor & (1 << 2)) >> 2;
+                    if (contentChecksumFlag) {
+                        info->usesCheck = 1;
+                        ERROR_IF(fseek(srcFile, 4, SEEK_CUR) != 0,
+                                info_frame_error, "Error: could not skip past checksum");
+                }   }
+                info->numActualFrames++;
+            }
+            /* Skippable frame */
+            else if ((magicNumber & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) {
+                U32 const frameSize = MEM_readLE32(headerBuffer + 4);
+                long const seek = (long)(8 + frameSize - numBytesRead);
+                ERROR_IF(LONG_SEEK(srcFile, seek, SEEK_CUR) != 0,
+                        info_frame_error, "Error: could not find end of skippable frame");
+                info->numSkippableFrames++;
+            }
+            /* unknown content */
+            else {
+                return info_not_zstd;
+            }
+        }  /* magic number analysis */
+    }  /* end analyzing frames */
+    return info_success;
+}
+
+
+static InfoError
+getFileInfo_fileConfirmed(fileInfo_t* info, const char* inFileName)
+{
+    InfoError status;
+    FILE* const srcFile = FIO_openSrcFile(inFileName);
+    ERROR_IF(srcFile == NULL, info_file_error, "Error: could not open source file %s", inFileName);
+
+    info->compressedSize = UTIL_getFileSize(inFileName);
+    status = FIO_analyzeFrames(info, srcFile);
+
+    fclose(srcFile);
+    info->nbFiles = 1;
+    return status;
+}
+
+
+/** getFileInfo() :
+ *  Reads information from file, stores in *info
+ * @return : InfoError status
+ */
+static InfoError
+getFileInfo(fileInfo_t* info, const char* srcFileName)
+{
+    ERROR_IF(!UTIL_isRegularFile(srcFileName),
+            info_file_error, "Error : %s is not a file", srcFileName);
+    return getFileInfo_fileConfirmed(info, srcFileName);
+}
+
+
+static void
+displayInfo(const char* inFileName, const fileInfo_t* info, int displayLevel)
+{
+    unsigned const unit = info->compressedSize < (1 MB) ? (1 KB) : (1 MB);
+    const char* const unitStr = info->compressedSize < (1 MB) ? "KB" : "MB";
+    double const windowSizeUnit = (double)info->windowSize / unit;
+    double const compressedSizeUnit = (double)info->compressedSize / unit;
+    double const decompressedSizeUnit = (double)info->decompressedSize / unit;
+    double const ratio = (info->compressedSize == 0) ? 0 : ((double)info->decompressedSize)/info->compressedSize;
+    const char* const checkString = (info->usesCheck ? "XXH64" : "None");
+    if (displayLevel <= 2) {
+        if (!info->decompUnavailable) {
+            DISPLAYOUT("%6d  %5d  %7.2f %2s  %9.2f %2s  %5.3f  %5s  %s\n",
+                    info->numSkippableFrames + info->numActualFrames,
+                    info->numSkippableFrames,
+                    compressedSizeUnit, unitStr, decompressedSizeUnit, unitStr,
+                    ratio, checkString, inFileName);
+        } else {
+            DISPLAYOUT("%6d  %5d  %7.2f %2s                       %5s  %s\n",
+                    info->numSkippableFrames + info->numActualFrames,
+                    info->numSkippableFrames,
+                    compressedSizeUnit, unitStr,
+                    checkString, inFileName);
+        }
+    } else {
+        DISPLAYOUT("%s \n", inFileName);
+        DISPLAYOUT("# Zstandard Frames: %d\n", info->numActualFrames);
+        if (info->numSkippableFrames)
+            DISPLAYOUT("# Skippable Frames: %d\n", info->numSkippableFrames);
+        DISPLAYOUT("Window Size: %.2f %2s (%llu B)\n",
+                   windowSizeUnit, unitStr,
+                   (unsigned long long)info->windowSize);
+        DISPLAYOUT("Compressed Size: %.2f %2s (%llu B)\n",
+                    compressedSizeUnit, unitStr,
+                    (unsigned long long)info->compressedSize);
+        if (!info->decompUnavailable) {
+            DISPLAYOUT("Decompressed Size: %.2f %2s (%llu B)\n",
+                    decompressedSizeUnit, unitStr,
+                    (unsigned long long)info->decompressedSize);
+            DISPLAYOUT("Ratio: %.4f\n", ratio);
+        }
+        DISPLAYOUT("Check: %s\n", checkString);
+        DISPLAYOUT("\n");
+    }
+}
+
+static fileInfo_t FIO_addFInfo(fileInfo_t fi1, fileInfo_t fi2)
+{
+    fileInfo_t total;
+    memset(&total, 0, sizeof(total));
+    total.numActualFrames = fi1.numActualFrames + fi2.numActualFrames;
+    total.numSkippableFrames = fi1.numSkippableFrames + fi2.numSkippableFrames;
+    total.compressedSize = fi1.compressedSize + fi2.compressedSize;
+    total.decompressedSize = fi1.decompressedSize + fi2.decompressedSize;
+    total.decompUnavailable = fi1.decompUnavailable | fi2.decompUnavailable;
+    total.usesCheck = fi1.usesCheck & fi2.usesCheck;
+    total.nbFiles = fi1.nbFiles + fi2.nbFiles;
+    return total;
+}
+
+static int
+FIO_listFile(fileInfo_t* total, const char* inFileName, int displayLevel)
+{
+    fileInfo_t info;
+    memset(&info, 0, sizeof(info));
+    {   InfoError const error = getFileInfo(&info, inFileName);
+        switch (error) {
+            case info_frame_error:
+                /* display error, but provide output */
+                DISPLAYLEVEL(1, "Error while parsing \"%s\" \n", inFileName);
+                break;
+            case info_not_zstd:
+                DISPLAYOUT("File \"%s\" not compressed by zstd \n", inFileName);
+                if (displayLevel > 2) DISPLAYOUT("\n");
+                return 1;
+            case info_file_error:
+                /* error occurred while opening the file */
+                if (displayLevel > 2) DISPLAYOUT("\n");
+                return 1;
+            case info_truncated_input:
+                DISPLAYOUT("File \"%s\" is truncated \n", inFileName);
+                if (displayLevel > 2) DISPLAYOUT("\n");
+                return 1;
+            case info_success:
+            default:
+                break;
+        }
+
+        displayInfo(inFileName, &info, displayLevel);
+        *total = FIO_addFInfo(*total, info);
+        assert(error == info_success || error == info_frame_error);
+        return (int)error;
+    }
+}
+
+int FIO_listMultipleFiles(unsigned numFiles, const char** filenameTable, int displayLevel)
+{
+    /* ensure no specified input is stdin (needs fseek() capability) */
+    {   unsigned u;
+        for (u=0; u<numFiles;u++) {
+            ERROR_IF(!strcmp (filenameTable[u], stdinmark),
+                    1, "zstd: --list does not support reading from standard input");
+    }   }
+
+    if (numFiles == 0) {
+        if (!IS_CONSOLE(stdin)) {
+            DISPLAYLEVEL(1, "zstd: --list does not support reading from standard input \n");
+        }
+        DISPLAYLEVEL(1, "No files given \n");
+        return 1;
+    }
+
+    if (displayLevel <= 2) {
+        DISPLAYOUT("Frames  Skips  Compressed  Uncompressed  Ratio  Check  Filename\n");
+    }
+    {   int error = 0;
+        fileInfo_t total;
+        memset(&total, 0, sizeof(total));
+        total.usesCheck = 1;
+        /* --list each file, and check for any error */
+        {   unsigned u;
+            for (u=0; u<numFiles;u++) {
+                error |= FIO_listFile(&total, filenameTable[u], displayLevel);
+        }   }
+        if (numFiles > 1 && displayLevel <= 2) {   /* display total */
+            unsigned const unit = total.compressedSize < (1 MB) ? (1 KB) : (1 MB);
+            const char* const unitStr = total.compressedSize < (1 MB) ? "KB" : "MB";
+            double const compressedSizeUnit = (double)total.compressedSize / unit;
+            double const decompressedSizeUnit = (double)total.decompressedSize / unit;
+            double const ratio = (total.compressedSize == 0) ? 0 : ((double)total.decompressedSize)/total.compressedSize;
+            const char* const checkString = (total.usesCheck ? "XXH64" : "");
+            DISPLAYOUT("----------------------------------------------------------------- \n");
+            if (total.decompUnavailable) {
+                DISPLAYOUT("%6d  %5d  %7.2f %2s                       %5s  %u files\n",
+                        total.numSkippableFrames + total.numActualFrames,
+                        total.numSkippableFrames,
+                        compressedSizeUnit, unitStr,
+                        checkString, (unsigned)total.nbFiles);
+            } else {
+                DISPLAYOUT("%6d  %5d  %7.2f %2s  %9.2f %2s  %5.3f  %5s  %u files\n",
+                        total.numSkippableFrames + total.numActualFrames,
+                        total.numSkippableFrames,
+                        compressedSizeUnit, unitStr, decompressedSizeUnit, unitStr,
+                        ratio, checkString, (unsigned)total.nbFiles);
+        }   }
+        return error;
+    }
+}
+
+
+#endif /* #ifndef ZSTD_NODECOMPRESS */
diff --git a/src/zstd/programs/fileio.h b/src/zstd/programs/fileio.h
new file mode 100644
index 000000000..2fbf01f82
--- /dev/null
+++ b/src/zstd/programs/fileio.h
@@ -0,0 +1,158 @@
+/*
+ * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
+ */
+
+
+#ifndef FILEIO_H_23981798732
+#define FILEIO_H_23981798732
+
+#define ZSTD_STATIC_LINKING_ONLY   /* ZSTD_compressionParameters */
+#include "../lib/zstd.h"           /* ZSTD_* */
+
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
+
+/* *************************************
+*  Special i/o constants
+**************************************/
+#define stdinmark  "/*stdin*\\"
+#define stdoutmark "/*stdout*\\"
+#ifdef _WIN32
+#  define nulmark "NUL"
+#else
+#  define nulmark "/dev/null"
+#endif
+
+/**
+ * We test whether the extension we found starts with 't', and if so, we append
+ * ".tar" to the end of the output name.
+ */
+#define LZMA_EXTENSION  ".lzma"
+#define XZ_EXTENSION    ".xz"
+#define TXZ_EXTENSION   ".txz"
+
+#define GZ_EXTENSION    ".gz"
+#define TGZ_EXTENSION   ".tgz"
+
+#define ZSTD_EXTENSION  ".zst"
+#define TZSTD_EXTENSION ".tzst"
+
+#define LZ4_EXTENSION   ".lz4"
+#define TLZ4_EXTENSION  ".tlz4"
+
+
+/*-*************************************
+*  Types
+***************************************/
+typedef enum { FIO_zstdCompression, FIO_gzipCompression, FIO_xzCompression, FIO_lzmaCompression, FIO_lz4Compression } FIO_compressionType_t;
+
+typedef struct FIO_prefs_s FIO_prefs_t;
+
+FIO_prefs_t* FIO_createPreferences(void);
+void FIO_freePreferences(FIO_prefs_t* const prefs);
+
+typedef struct FIO_display_prefs_s FIO_display_prefs_t;
+
+/*-*************************************
+*  Parameters
+***************************************/
+void FIO_setCompressionType(FIO_prefs_t* const prefs, FIO_compressionType_t compressionType);
+void FIO_overwriteMode(FIO_prefs_t* const prefs);
+void FIO_setAdaptiveMode(FIO_prefs_t* const prefs, unsigned adapt);
+void FIO_setAdaptMin(FIO_prefs_t* const prefs, int minCLevel);
+void FIO_setAdaptMax(FIO_prefs_t* const prefs, int maxCLevel);
+void FIO_setBlockSize(FIO_prefs_t* const prefs, int blockSize);
+void FIO_setChecksumFlag(FIO_prefs_t* const prefs, int checksumFlag);
+void FIO_setDictIDFlag(FIO_prefs_t* const prefs, int dictIDFlag);
+void FIO_setLdmBucketSizeLog(FIO_prefs_t* const prefs, int ldmBucketSizeLog);
+void FIO_setLdmFlag(FIO_prefs_t* const prefs, unsigned ldmFlag);
+void FIO_setLdmHashRateLog(FIO_prefs_t* const prefs, int ldmHashRateLog);
+void FIO_setLdmHashLog(FIO_prefs_t* const prefs, int ldmHashLog);
+void FIO_setLdmMinMatch(FIO_prefs_t* const prefs, int ldmMinMatch);
+void FIO_setMemLimit(FIO_prefs_t* const prefs, unsigned memLimit);
+void FIO_setNbWorkers(FIO_prefs_t* const prefs, int nbWorkers);
+void FIO_setOverlapLog(FIO_prefs_t* const prefs, int overlapLog);
+void FIO_setRemoveSrcFile(FIO_prefs_t* const prefs, unsigned flag);
+void FIO_setSparseWrite(FIO_prefs_t* const prefs, unsigned sparse);  /**< 0: no sparse; 1: disable on stdout; 2: always enabled */
+void FIO_setRsyncable(FIO_prefs_t* const prefs, int rsyncable);
+void FIO_setStreamSrcSize(FIO_prefs_t* const prefs, size_t streamSrcSize);
+void FIO_setTargetCBlockSize(FIO_prefs_t* const prefs, size_t targetCBlockSize);
+void FIO_setSrcSizeHint(FIO_prefs_t* const prefs, size_t srcSizeHint);
+void FIO_setTestMode(FIO_prefs_t* const prefs, int testMode);
+void FIO_setLiteralCompressionMode(
+        FIO_prefs_t* const prefs,
+        ZSTD_literalCompressionMode_e mode);
+
+void FIO_setNoProgress(unsigned noProgress);
+void FIO_setNotificationLevel(int level);
+void FIO_setExcludeCompressedFile(FIO_prefs_t* const prefs, int excludeCompressedFiles);
+void FIO_setPatchFromMode(FIO_prefs_t* const prefs, int value);
+void FIO_setContentSize(FIO_prefs_t* const prefs, int value);
+
+/*-*************************************
+*  Single File functions
+***************************************/
+/** FIO_compressFilename() :
+ * @return : 0 == ok;  1 == pb with src file. */
+int FIO_compressFilename (FIO_prefs_t* const prefs,
+                          const char* outfilename, const char* infilename,
+                          const char* dictFileName, int compressionLevel,
+                          ZSTD_compressionParameters comprParams);
+
+/** FIO_decompressFilename() :
+ * @return : 0 == ok;  1 == pb with src file. */
+int FIO_decompressFilename (FIO_prefs_t* const prefs,
+                            const char* outfilename, const char* infilename, const char* dictFileName);
+
+int FIO_listMultipleFiles(unsigned numFiles, const char** filenameTable, int displayLevel);
+
+
+/*-*************************************
+*  Multiple File functions
+***************************************/
+/** FIO_compressMultipleFilenames() :
+ * @return : nb of missing files */
+int FIO_compressMultipleFilenames(FIO_prefs_t* const prefs,
+                                  const char** inFileNamesTable, unsigned nbFiles,
+                                  const char* outDirName,
+                                  const char* outFileName, const char* suffix,
+                                  const char* dictFileName, int compressionLevel,
+                                  ZSTD_compressionParameters comprParams);
+
+/** FIO_decompressMultipleFilenames() :
+ * @return : nb of missing or skipped files */
+int FIO_decompressMultipleFilenames(FIO_prefs_t* const prefs,
+                                    const char** srcNamesTable, unsigned nbFiles,
+                                    const char* outDirName,
+                                    const char* outFileName,
+                                    const char* dictFileName);
+
+/* FIO_checkFilenameCollisions() :
+ * Checks for and warns if there are any files that would have the same output path
+ */
+int FIO_checkFilenameCollisions(const char** filenameTable, unsigned nbFiles);
+
+
+
+/*-*************************************
+*  Advanced stuff (should actually be hosted elsewhere)
+***************************************/
+
+/* custom crash signal handler */
+void FIO_addAbortHandler(void);
+
+
+
+#if defined (__cplusplus)
+}
+#endif
+
+#endif  /* FILEIO_H_23981798732 */
diff --git a/src/zstd/programs/platform.h b/src/zstd/programs/platform.h
new file mode 100644
index 000000000..2b4b9f2d8
--- /dev/null
+++ b/src/zstd/programs/platform.h
@@ -0,0 +1,208 @@
+/*
+ * Copyright (c) 2016-2020, Przemyslaw Skibinski, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
+ */
+
+#ifndef PLATFORM_H_MODULE
+#define PLATFORM_H_MODULE
+
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
+
+
+/* **************************************
+*  Compiler Options
+****************************************/
+#if defined(_MSC_VER)
+#  define _CRT_SECURE_NO_WARNINGS    /* Disable Visual Studio warning messages for fopen, strncpy, strerror */
+#  if (_MSC_VER <= 1800)             /* 1800 == Visual Studio 2013 */
+#    define _CRT_SECURE_NO_DEPRECATE /* VS2005 - must be declared before <io.h> and <windows.h> */
+#    define snprintf sprintf_s       /* snprintf unsupported by Visual <= 2013 */
+#  endif
+#  pragma warning(disable : 4127)    /* disable: C4127: conditional expression is constant */
+#endif
+
+
+/* **************************************
+*  Detect 64-bit OS
+*  http://nadeausoftware.com/articles/2012/02/c_c_tip_how_detect_processor_type_using_compiler_predefined_macros
+****************************************/
+#if defined __ia64 || defined _M_IA64                                                                               /* Intel Itanium */ \
+  || defined __powerpc64__ || defined __ppc64__ || defined __PPC64__                                                /* POWER 64-bit */  \
+  || (defined __sparc && (defined __sparcv9 || defined __sparc_v9__ || defined __arch64__)) || defined __sparc64__  /* SPARC 64-bit */  \
+  || defined __x86_64__s || defined _M_X64                                                                          /* x86 64-bit */    \
+  || defined __arm64__ || defined __aarch64__ || defined __ARM64_ARCH_8__                                           /* ARM 64-bit */    \
+  || (defined __mips  && (__mips == 64 || __mips == 4 || __mips == 3))                                              /* MIPS 64-bit */   \
+  || defined _LP64 || defined __LP64__ /* NetBSD, OpenBSD */ || defined __64BIT__ /* AIX */ || defined _ADDR64 /* Cray */               \
+  || (defined __SIZEOF_POINTER__ && __SIZEOF_POINTER__ == 8) /* gcc */
+#  if !defined(__64BIT__)
+#    define __64BIT__  1
+#  endif
+#endif
+
+
+/* *********************************************************
+*  Turn on Large Files support (>4GB) for 32-bit Linux/Unix
+***********************************************************/
+#if !defined(__64BIT__) || defined(__MINGW32__)    /* No point defining Large file for 64 bit but MinGW-w64 requires it */
+#  if !defined(_FILE_OFFSET_BITS)
+#    define _FILE_OFFSET_BITS 64                   /* turn off_t into a 64-bit type for ftello, fseeko */
+#  endif
+#  if !defined(_LARGEFILE_SOURCE)                  /* obsolete macro, replaced with _FILE_OFFSET_BITS */
+#    define _LARGEFILE_SOURCE 1                    /* Large File Support extension (LFS) - fseeko, ftello */
+#  endif
+#  if defined(_AIX) || defined(__hpux)
+#    define _LARGE_FILES                           /* Large file support on 32-bits AIX and HP-UX */
+#  endif
+#endif
+
+
+/* ************************************************************
+*  Detect POSIX version
+*  PLATFORM_POSIX_VERSION = 0 for non-Unix e.g. Windows
+*  PLATFORM_POSIX_VERSION = 1 for Unix-like but non-POSIX
+*  PLATFORM_POSIX_VERSION > 1 is equal to found _POSIX_VERSION
+*  Value of PLATFORM_POSIX_VERSION can be forced on command line
+***************************************************************/
+#ifndef PLATFORM_POSIX_VERSION
+
+#  if (defined(__APPLE__) && defined(__MACH__)) || defined(__SVR4) || defined(_AIX) || defined(__hpux) /* POSIX.1-2001 (SUSv3) conformant */ \
+     || defined(__DragonFly__) || defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__)  /* BSD distros */
+     /* exception rule : force posix version to 200112L,
+      * note: it's better to use unistd.h's _POSIX_VERSION whenever possible */
+#    define PLATFORM_POSIX_VERSION 200112L
+
+/* try to determine posix version through official unistd.h's _POSIX_VERSION (http://pubs.opengroup.org/onlinepubs/7908799/xsh/unistd.h.html).
+ * note : there is no simple way to know in advance if <unistd.h> is present or not on target system,
+ * Posix specification mandates its presence and its content, but target system must respect this spec.
+ * It's necessary to _not_ #include <unistd.h> whenever target OS is not unix-like
+ * otherwise it will block preprocessing stage.
+ * The following list of build macros tries to "guess" if target OS is likely unix-like, and therefore can #include <unistd.h>
+ */
+#  elif !defined(_WIN32) \
+     && ( defined(__unix__) || defined(__unix) \
+       || defined(__midipix__) || defined(__VMS) || defined(__HAIKU__) )
+
+#    if defined(__linux__) || defined(__linux) || defined(__CYGWIN__)
+#      ifndef _POSIX_C_SOURCE
+#        define _POSIX_C_SOURCE 200809L  /* feature test macro : https://www.gnu.org/software/libc/manual/html_node/Feature-Test-Macros.html */
+#      endif
+#    endif
+#    include <unistd.h>  /* declares _POSIX_VERSION */
+#    if defined(_POSIX_VERSION)  /* POSIX compliant */
+#      define PLATFORM_POSIX_VERSION _POSIX_VERSION
+#    else
+#      define PLATFORM_POSIX_VERSION 1
+#    endif
+
+#  else  /* non-unix target platform (like Windows) */
+#    define PLATFORM_POSIX_VERSION 0
+#  endif
+
+#endif   /* PLATFORM_POSIX_VERSION */
+
+
+#if PLATFORM_POSIX_VERSION > 1
+   /* glibc < 2.26 may not expose struct timespec def without this.
+    * See issue #1920. */
+#  ifndef _ATFILE_SOURCE
+#    define _ATFILE_SOURCE
+#  endif
+#endif
+
+
+/*-*********************************************
+*  Detect if isatty() and fileno() are available
+************************************************/
+#if (defined(__linux__) && (PLATFORM_POSIX_VERSION > 1)) \
+ || (PLATFORM_POSIX_VERSION >= 200112L) \
+ || defined(__DJGPP__)
+#  include <unistd.h>   /* isatty */
+#  include <stdio.h>    /* fileno */
+#  define IS_CONSOLE(stdStream) isatty(fileno(stdStream))
+#elif defined(MSDOS) || defined(OS2)
+#  include <io.h>       /* _isatty */
+#  define IS_CONSOLE(stdStream) _isatty(_fileno(stdStream))
+#elif defined(WIN32) || defined(_WIN32)
+#  include <io.h>      /* _isatty */
+#  include <windows.h> /* DeviceIoControl, HANDLE, FSCTL_SET_SPARSE */
+#  include <stdio.h>   /* FILE */
+static __inline int IS_CONSOLE(FILE* stdStream) {
+    DWORD dummy;
+    return _isatty(_fileno(stdStream)) && GetConsoleMode((HANDLE)_get_osfhandle(_fileno(stdStream)), &dummy);
+}
+#else
+#  define IS_CONSOLE(stdStream) 0
+#endif
+
+
+/******************************
+*  OS-specific IO behaviors
+******************************/
+#if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(_WIN32)
+#  include <fcntl.h>   /* _O_BINARY */
+#  include <io.h>      /* _setmode, _fileno, _get_osfhandle */
+#  if !defined(__DJGPP__)
+#    include <windows.h> /* DeviceIoControl, HANDLE, FSCTL_SET_SPARSE */
+#    include <winioctl.h> /* FSCTL_SET_SPARSE */
+#    define SET_BINARY_MODE(file) { int const unused=_setmode(_fileno(file), _O_BINARY); (void)unused; }
+#    define SET_SPARSE_FILE_MODE(file) { DWORD dw; DeviceIoControl((HANDLE) _get_osfhandle(_fileno(file)), FSCTL_SET_SPARSE, 0, 0, 0, 0, &dw, 0); }
+#  else
+#    define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)
+#    define SET_SPARSE_FILE_MODE(file)
+#  endif
+#else
+#  define SET_BINARY_MODE(file)
+#  define SET_SPARSE_FILE_MODE(file)
+#endif
+
+
+#ifndef ZSTD_SPARSE_DEFAULT
+#  if (defined(__APPLE__) && defined(__MACH__))
+#    define ZSTD_SPARSE_DEFAULT 0
+#  else
+#    define ZSTD_SPARSE_DEFAULT 1
+#  endif
+#endif
+
+
+#ifndef ZSTD_START_SYMBOLLIST_FRAME
+#  ifdef __linux__
+#    define ZSTD_START_SYMBOLLIST_FRAME 2
+#  elif defined __APPLE__
+#    define ZSTD_START_SYMBOLLIST_FRAME 4
+#  else
+#    define ZSTD_START_SYMBOLLIST_FRAME 0
+#  endif
+#endif
+
+
+#ifndef ZSTD_SETPRIORITY_SUPPORT
+   /* mandates presence of <sys/resource.h> and support for setpriority() : http://man7.org/linux/man-pages/man2/setpriority.2.html */
+#  define ZSTD_SETPRIORITY_SUPPORT (PLATFORM_POSIX_VERSION >= 200112L)
+#endif
+
+
+#ifndef ZSTD_NANOSLEEP_SUPPORT
+   /* mandates support of nanosleep() within <time.h> : http://man7.org/linux/man-pages/man2/nanosleep.2.html */
+#  if (defined(__linux__) && (PLATFORM_POSIX_VERSION >= 199309L)) \
+   || (PLATFORM_POSIX_VERSION >= 200112L)
+#     define ZSTD_NANOSLEEP_SUPPORT 1
+#  else
+#     define ZSTD_NANOSLEEP_SUPPORT 0
+#  endif
+#endif
+
+
+#if defined (__cplusplus)
+}
+#endif
+
+#endif /* PLATFORM_H_MODULE */
diff --git a/src/zstd/programs/timefn.c b/src/zstd/programs/timefn.c
new file mode 100644
index 000000000..95460d0d9
--- /dev/null
+++ b/src/zstd/programs/timefn.c
@@ -0,0 +1,169 @@
+/*
+ * Copyright (c) 2019-2020, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
+ */
+
+
+/* ===  Dependencies  === */
+
+#include "timefn.h"
+
+
+/*-****************************************
+*  Time functions
+******************************************/
+
+#if defined(_WIN32)   /* Windows */
+
+#include <stdlib.h>   /* abort */
+#include <stdio.h>    /* perror */
+
+UTIL_time_t UTIL_getTime(void) { UTIL_time_t x; QueryPerformanceCounter(&x); return x; }
+
+PTime UTIL_getSpanTimeMicro(UTIL_time_t clockStart, UTIL_time_t clockEnd)
+{
+    static LARGE_INTEGER ticksPerSecond;
+    static int init = 0;
+    if (!init) {
+        if (!QueryPerformanceFrequency(&ticksPerSecond)) {
+            perror("timefn::QueryPerformanceFrequency");
+            abort();
+        }
+        init = 1;
+    }
+    return 1000000ULL*(clockEnd.QuadPart - clockStart.QuadPart)/ticksPerSecond.QuadPart;
+}
+
+PTime UTIL_getSpanTimeNano(UTIL_time_t clockStart, UTIL_time_t clockEnd)
+{
+    static LARGE_INTEGER ticksPerSecond;
+    static int init = 0;
+    if (!init) {
+        if (!QueryPerformanceFrequency(&ticksPerSecond)) {
+            perror("timefn::QueryPerformanceFrequency");
+            abort();
+        }
+        init = 1;
+    }
+    return 1000000000ULL*(clockEnd.QuadPart - clockStart.QuadPart)/ticksPerSecond.QuadPart;
+}
+
+
+
+#elif defined(__APPLE__) && defined(__MACH__)
+
+UTIL_time_t UTIL_getTime(void) { return mach_absolute_time(); }
+
+PTime UTIL_getSpanTimeMicro(UTIL_time_t clockStart, UTIL_time_t clockEnd)
+{
+    static mach_timebase_info_data_t rate;
+    static int init = 0;
+    if (!init) {
+        mach_timebase_info(&rate);
+        init = 1;
+    }
+    return (((clockEnd - clockStart) * (PTime)rate.numer) / ((PTime)rate.denom))/1000ULL;
+}
+
+PTime UTIL_getSpanTimeNano(UTIL_time_t clockStart, UTIL_time_t clockEnd)
+{
+    static mach_timebase_info_data_t rate;
+    static int init = 0;
+    if (!init) {
+        mach_timebase_info(&rate);
+        init = 1;
+    }
+    return ((clockEnd - clockStart) * (PTime)rate.numer) / ((PTime)rate.denom);
+}
+
+
+/* C11 requires timespec_get, but FreeBSD 11 lacks it, while still claiming C11 compliance.
+   Android also lacks it but does define TIME_UTC. */
+#elif (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L) /* C11 */) \
+    && defined(TIME_UTC) && !defined(__ANDROID__)
+
+#include <stdlib.h>   /* abort */
+#include <stdio.h>    /* perror */
+
+UTIL_time_t UTIL_getTime(void)
+{
+    /* time must be initialized, othersize it may fail msan test.
+     * No good reason, likely a limitation of timespec_get() for some target */
+    UTIL_time_t time = UTIL_TIME_INITIALIZER;
+    if (timespec_get(&time, TIME_UTC) != TIME_UTC) {
+        perror("timefn::timespec_get");
+        abort();
+    }
+    return time;
+}
+
+static UTIL_time_t UTIL_getSpanTime(UTIL_time_t begin, UTIL_time_t end)
+{
+    UTIL_time_t diff;
+    if (end.tv_nsec < begin.tv_nsec) {
+        diff.tv_sec = (end.tv_sec - 1) - begin.tv_sec;
+        diff.tv_nsec = (end.tv_nsec + 1000000000ULL) - begin.tv_nsec;
+    } else {
+        diff.tv_sec = end.tv_sec - begin.tv_sec;
+        diff.tv_nsec = end.tv_nsec - begin.tv_nsec;
+    }
+    return diff;
+}
+
+PTime UTIL_getSpanTimeMicro(UTIL_time_t begin, UTIL_time_t end)
+{
+    UTIL_time_t const diff = UTIL_getSpanTime(begin, end);
+    PTime micro = 0;
+    micro += 1000000ULL * diff.tv_sec;
+    micro += diff.tv_nsec / 1000ULL;
+    return micro;
+}
+
+PTime UTIL_getSpanTimeNano(UTIL_time_t begin, UTIL_time_t end)
+{
+    UTIL_time_t const diff = UTIL_getSpanTime(begin, end);
+    PTime nano = 0;
+    nano += 1000000000ULL * diff.tv_sec;
+    nano += diff.tv_nsec;
+    return nano;
+}
+
+
+
+#else   /* relies on standard C90 (note : clock_t measurements can be wrong when using multi-threading) */
+
+UTIL_time_t UTIL_getTime(void) { return clock(); }
+PTime UTIL_getSpanTimeMicro(UTIL_time_t clockStart, UTIL_time_t clockEnd) { return 1000000ULL * (clockEnd - clockStart) / CLOCKS_PER_SEC; }
+PTime UTIL_getSpanTimeNano(UTIL_time_t clockStart, UTIL_time_t clockEnd) { return 1000000000ULL * (clockEnd - clockStart) / CLOCKS_PER_SEC; }
+
+#endif
+
+
+
+/* returns time span in microseconds */
+PTime UTIL_clockSpanMicro(UTIL_time_t clockStart )
+{
+    UTIL_time_t const clockEnd = UTIL_getTime();
+    return UTIL_getSpanTimeMicro(clockStart, clockEnd);
+}
+
+/* returns time span in microseconds */
+PTime UTIL_clockSpanNano(UTIL_time_t clockStart )
+{
+    UTIL_time_t const clockEnd = UTIL_getTime();
+    return UTIL_getSpanTimeNano(clockStart, clockEnd);
+}
+
+void UTIL_waitForNextTick(void)
+{
+    UTIL_time_t const clockStart = UTIL_getTime();
+    UTIL_time_t clockEnd;
+    do {
+        clockEnd = UTIL_getTime();
+    } while (UTIL_getSpanTimeNano(clockStart, clockEnd) == 0);
+}
diff --git a/src/zstd/programs/timefn.h b/src/zstd/programs/timefn.h
new file mode 100644
index 000000000..eb3c13093
--- /dev/null
+++ b/src/zstd/programs/timefn.h
@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
+ */
+
+#ifndef TIME_FN_H_MODULE_287987
+#define TIME_FN_H_MODULE_287987
+
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
+
+/*-****************************************
+*  Dependencies
+******************************************/
+#include <time.h>         /* clock_t, clock, CLOCKS_PER_SEC */
+
+
+
+/*-****************************************
+*  Local Types
+******************************************/
+
+#if !defined (__VMS) && (defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */) )
+# include <stdint.h>
+  typedef uint64_t           PTime;  /* Precise Time */
+#else
+  typedef unsigned long long PTime;  /* does not support compilers without long long support */
+#endif
+
+
+
+/*-****************************************
+*  Time functions
+******************************************/
+#if defined(_WIN32)   /* Windows */
+
+    #include <windows.h>   /* LARGE_INTEGER */
+    typedef LARGE_INTEGER UTIL_time_t;
+    #define UTIL_TIME_INITIALIZER { { 0, 0 } }
+
+#elif defined(__APPLE__) && defined(__MACH__)
+
+    #include <mach/mach_time.h>
+    typedef PTime UTIL_time_t;
+    #define UTIL_TIME_INITIALIZER 0
+
+/* C11 requires timespec_get, but FreeBSD 11 lacks it, while still claiming C11 compliance.
+   Android also lacks it but does define TIME_UTC. */
+#elif (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L) /* C11 */) \
+    && defined(TIME_UTC) && !defined(__ANDROID__)
+
+    typedef struct timespec UTIL_time_t;
+    #define UTIL_TIME_INITIALIZER { 0, 0 }
+
+#else   /* relies on standard C90 (note : clock_t measurements can be wrong when using multi-threading) */
+
+    typedef clock_t UTIL_time_t;
+    #define UTIL_TIME_INITIALIZER 0
+
+#endif
+
+
+UTIL_time_t UTIL_getTime(void);
+PTime UTIL_getSpanTimeMicro(UTIL_time_t clockStart, UTIL_time_t clockEnd);
+PTime UTIL_getSpanTimeNano(UTIL_time_t clockStart, UTIL_time_t clockEnd);
+
+#define SEC_TO_MICRO ((PTime)1000000)
+PTime UTIL_clockSpanMicro(UTIL_time_t clockStart);
+PTime UTIL_clockSpanNano(UTIL_time_t clockStart);
+
+void UTIL_waitForNextTick(void);
+
+
+#if defined (__cplusplus)
+}
+#endif
+
+#endif /* TIME_FN_H_MODULE_287987 */
diff --git a/src/zstd/programs/util.c b/src/zstd/programs/util.c
new file mode 100644
index 000000000..ab1abd3b1
--- /dev/null
+++ b/src/zstd/programs/util.c
@@ -0,0 +1,938 @@
+/*
+ * Copyright (c) 2016-2020, Przemyslaw Skibinski, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
+ */
+
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
+
+/*-****************************************
+*  Dependencies
+******************************************/
+#include "util.h"       /* note : ensure that platform.h is included first ! */
+#include <stdlib.h>     /* malloc, realloc, free */
+#include <stdio.h>      /* fprintf */
+#include <time.h>       /* clock_t, clock, CLOCKS_PER_SEC, nanosleep */
+#include <errno.h>
+#include <assert.h>
+
+#if defined(_WIN32)
+#  include <sys/utime.h>  /* utime */
+#  include <io.h>         /* _chmod */
+#else
+#  include <unistd.h>     /* chown, stat */
+#  if PLATFORM_POSIX_VERSION < 200809L
+#    include <utime.h>    /* utime */
+#  else
+#    include <fcntl.h>    /* AT_FDCWD */
+#    include <sys/stat.h> /* utimensat */
+#  endif
+#endif
+
+#if defined(_MSC_VER) || defined(__MINGW32__) || defined (__MSVCRT__)
+#include <direct.h>     /* needed for _mkdir in windows */
+#endif
+
+#if defined(__linux__) || (PLATFORM_POSIX_VERSION >= 200112L)  /* opendir, readdir require POSIX.1-2001 */
+#  include <dirent.h>       /* opendir, readdir */
+#  include <string.h>       /* strerror, memcpy */
+#endif /* #ifdef _WIN32 */
+
+
+/*-****************************************
+*  Internal Macros
+******************************************/
+
+/* CONTROL is almost like an assert(), but is never disabled.
+ * It's designed for failures that may happen rarely,
+ * but we don't want to maintain a specific error code path for them,
+ * such as a malloc() returning NULL for example.
+ * Since it's always active, this macro can trigger side effects.
+ */
+#define CONTROL(c)  {         \
+    if (!(c)) {               \
+        UTIL_DISPLAYLEVEL(1, "Error : %s, %i : %s",  \
+                          __FILE__, __LINE__, #c);   \
+        exit(1);              \
+}   }
+
+/* console log */
+#define UTIL_DISPLAY(...)         fprintf(stderr, __VA_ARGS__)
+#define UTIL_DISPLAYLEVEL(l, ...) { if (g_utilDisplayLevel>=l) { UTIL_DISPLAY(__VA_ARGS__); } }
+
+/* A modified version of realloc().
+ * If UTIL_realloc() fails the original block is freed.
+ */
+UTIL_STATIC void* UTIL_realloc(void *ptr, size_t size)
+{
+    void *newptr = realloc(ptr, size);
+    if (newptr) return newptr;
+    free(ptr);
+    return NULL;
+}
+
+#if defined(_MSC_VER)
+    #define chmod _chmod
+#endif
+
+
+/*-****************************************
+*  Console log
+******************************************/
+int g_utilDisplayLevel;
+
+
+/*-*************************************
+*  Constants
+***************************************/
+#define LIST_SIZE_INCREASE   (8*1024)
+#define MAX_FILE_OF_FILE_NAMES_SIZE (1<<20)*50
+
+
+/*-*************************************
+*  Functions
+***************************************/
+
+int UTIL_fileExist(const char* filename)
+{
+    stat_t statbuf;
+#if defined(_MSC_VER)
+    int const stat_error = _stat64(filename, &statbuf);
+#else
+    int const stat_error = stat(filename, &statbuf);
+#endif
+    return !stat_error;
+}
+
+int UTIL_isRegularFile(const char* infilename)
+{
+    stat_t statbuf;
+    return UTIL_getFileStat(infilename, &statbuf); /* Only need to know whether it is a regular file */
+}
+
+int UTIL_getFileStat(const char* infilename, stat_t *statbuf)
+{
+    int r;
+#if defined(_MSC_VER)
+    r = _stat64(infilename, statbuf);
+    if (r || !(statbuf->st_mode & S_IFREG)) return 0;   /* No good... */
+#else
+    r = stat(infilename, statbuf);
+    if (r || !S_ISREG(statbuf->st_mode)) return 0;   /* No good... */
+#endif
+    return 1;
+}
+
+/* like chmod, but avoid changing permission of /dev/null */
+int UTIL_chmod(char const* filename, mode_t permissions)
+{
+    if (!strcmp(filename, "/dev/null")) return 0;   /* pretend success, but don't change anything */
+    return chmod(filename, permissions);
+}
+
+int UTIL_setFileStat(const char *filename, stat_t *statbuf)
+{
+    int res = 0;
+
+    if (!UTIL_isRegularFile(filename))
+        return -1;
+
+    /* set access and modification times */
+    /* We check that st_mtime is a macro here in order to give us confidence
+     * that struct stat has a struct timespec st_mtim member. We need this
+     * check because there are some platforms that claim to be POSIX 2008
+     * compliant but which do not have st_mtim... */
+#if (PLATFORM_POSIX_VERSION >= 200809L) && defined(st_mtime)
+    {
+        /* (atime, mtime) */
+        struct timespec timebuf[2] = { {0, UTIME_NOW} };
+        timebuf[1] = statbuf->st_mtim;
+        res += utimensat(AT_FDCWD, filename, timebuf, 0);
+    }
+#else
+    {
+        struct utimbuf timebuf;
+        timebuf.actime = time(NULL);
+        timebuf.modtime = statbuf->st_mtime;
+        res += utime(filename, &timebuf);
+    }
+#endif
+
+#if !defined(_WIN32)
+    res += chown(filename, statbuf->st_uid, statbuf->st_gid);  /* Copy ownership */
+#endif
+
+    res += UTIL_chmod(filename, statbuf->st_mode & 07777);  /* Copy file permissions */
+
+    errno = 0;
+    return -res; /* number of errors is returned */
+}
+
+int UTIL_isDirectory(const char* infilename)
+{
+    stat_t statbuf;
+#if defined(_MSC_VER)
+    int const r = _stat64(infilename, &statbuf);
+    if (!r && (statbuf.st_mode & _S_IFDIR)) return 1;
+#else
+    int const r = stat(infilename, &statbuf);
+    if (!r && S_ISDIR(statbuf.st_mode)) return 1;
+#endif
+    return 0;
+}
+
+int UTIL_compareStr(const void *p1, const void *p2) {
+    return strcmp(* (char * const *) p1, * (char * const *) p2);
+}
+
+int UTIL_isSameFile(const char* fName1, const char* fName2)
+{
+    assert(fName1 != NULL); assert(fName2 != NULL);
+#if defined(_MSC_VER) || defined(_WIN32)
+    /* note : Visual does not support file identification by inode.
+     *        inode does not work on Windows, even with a posix layer, like msys2.
+     *        The following work-around is limited to detecting exact name repetition only,
+     *        aka `filename` is considered different from `subdir/../filename` */
+    return !strcmp(fName1, fName2);
+#else
+    {   stat_t file1Stat;
+        stat_t file2Stat;
+        return UTIL_getFileStat(fName1, &file1Stat)
+            && UTIL_getFileStat(fName2, &file2Stat)
+            && (file1Stat.st_dev == file2Stat.st_dev)
+            && (file1Stat.st_ino == file2Stat.st_ino);
+    }
+#endif
+}
+
+/* UTIL_isFIFO : distinguish named pipes */
+int UTIL_isFIFO(const char* infilename)
+{
+/* macro guards, as defined in : https://linux.die.net/man/2/lstat */
+#if PLATFORM_POSIX_VERSION >= 200112L
+    stat_t statbuf;
+    int const r = UTIL_getFileStat(infilename, &statbuf);
+    if (!r && S_ISFIFO(statbuf.st_mode)) return 1;
+#endif
+    (void)infilename;
+    return 0;
+}
+
+int UTIL_isLink(const char* infilename)
+{
+/* macro guards, as defined in : https://linux.die.net/man/2/lstat */
+#if PLATFORM_POSIX_VERSION >= 200112L
+    stat_t statbuf;
+    int const r = lstat(infilename, &statbuf);
+    if (!r && S_ISLNK(statbuf.st_mode)) return 1;
+#endif
+    (void)infilename;
+    return 0;
+}
+
+U64 UTIL_getFileSize(const char* infilename)
+{
+    if (!UTIL_isRegularFile(infilename)) return UTIL_FILESIZE_UNKNOWN;
+    {   int r;
+#if defined(_MSC_VER)
+        struct __stat64 statbuf;
+        r = _stat64(infilename, &statbuf);
+        if (r || !(statbuf.st_mode & S_IFREG)) return UTIL_FILESIZE_UNKNOWN;
+#elif defined(__MINGW32__) && defined (__MSVCRT__)
+        struct _stati64 statbuf;
+        r = _stati64(infilename, &statbuf);
+        if (r || !(statbuf.st_mode & S_IFREG)) return UTIL_FILESIZE_UNKNOWN;
+#else
+        struct stat statbuf;
+        r = stat(infilename, &statbuf);
+        if (r || !S_ISREG(statbuf.st_mode)) return UTIL_FILESIZE_UNKNOWN;
+#endif
+        return (U64)statbuf.st_size;
+    }
+}
+
+
+U64 UTIL_getTotalFileSize(const char* const * fileNamesTable, unsigned nbFiles)
+{
+    U64 total = 0;
+    unsigned n;
+    for (n=0; n<nbFiles; n++) {
+        U64 const size = UTIL_getFileSize(fileNamesTable[n]);
+        if (size == UTIL_FILESIZE_UNKNOWN) return UTIL_FILESIZE_UNKNOWN;
+        total += size;
+    }
+    return total;
+}
+
+
+/* condition : @file must be valid, and not have reached its end.
+ * @return : length of line written into @buf, ended with `\0` instead of '\n',
+ *           or 0, if there is no new line */
+static size_t readLineFromFile(char* buf, size_t len, FILE* file)
+{
+    assert(!feof(file));
+    /* Work around Cygwin problem when len == 1 it returns NULL. */
+    if (len <= 1) return 0;
+    CONTROL( fgets(buf, (int) len, file) );
+    {   size_t linelen = strlen(buf);
+        if (strlen(buf)==0) return 0;
+        if (buf[linelen-1] == '\n') linelen--;
+        buf[linelen] = '\0';
+        return linelen+1;
+    }
+}
+
+/* Conditions :
+ *   size of @inputFileName file must be < @dstCapacity
+ *   @dst must be initialized
+ * @return : nb of lines
+ *       or -1 if there's an error
+ */
+static int
+readLinesFromFile(void* dst, size_t dstCapacity,
+            const char* inputFileName)
+{
+    int nbFiles = 0;
+    size_t pos = 0;
+    char* const buf = (char*)dst;
+    FILE* const inputFile = fopen(inputFileName, "r");
+
+    assert(dst != NULL);
+
+    if(!inputFile) {
+        if (g_utilDisplayLevel >= 1) perror("zstd:util:readLinesFromFile");
+        return -1;
+    }
+
+    while ( !feof(inputFile) ) {
+        size_t const lineLength = readLineFromFile(buf+pos, dstCapacity-pos, inputFile);
+        if (lineLength == 0) break;
+        assert(pos + lineLength < dstCapacity);
+        pos += lineLength;
+        ++nbFiles;
+    }
+
+    CONTROL( fclose(inputFile) == 0 );
+
+    return nbFiles;
+}
+
+/*Note: buf is not freed in case function successfully created table because filesTable->fileNames[0] = buf*/
+FileNamesTable*
+UTIL_createFileNamesTable_fromFileName(const char* inputFileName)
+{
+    size_t nbFiles = 0;
+    char* buf;
+    size_t bufSize;
+    size_t pos = 0;
+
+    if (!UTIL_fileExist(inputFileName) || !UTIL_isRegularFile(inputFileName))
+        return NULL;
+
+    {   U64 const inputFileSize = UTIL_getFileSize(inputFileName);
+        if(inputFileSize > MAX_FILE_OF_FILE_NAMES_SIZE)
+            return NULL;
+        bufSize = (size_t)(inputFileSize + 1); /* (+1) to add '\0' at the end of last filename */
+    }
+
+    buf = (char*) malloc(bufSize);
+    CONTROL( buf != NULL );
+
+    {   int const ret_nbFiles = readLinesFromFile(buf, bufSize, inputFileName);
+
+        if (ret_nbFiles <= 0) {
+          free(buf);
+          return NULL;
+        }
+        nbFiles = (size_t)ret_nbFiles;
+    }
+
+    {   const char** filenamesTable = (const char**) malloc(nbFiles * sizeof(*filenamesTable));
+        CONTROL(filenamesTable != NULL);
+
+        {   size_t fnb;
+            for (fnb = 0, pos = 0; fnb < nbFiles; fnb++) {
+                filenamesTable[fnb] = buf+pos;
+                pos += strlen(buf+pos)+1;  /* +1 for the finishing `\0` */
+        }   }
+        assert(pos <= bufSize);
+
+        return UTIL_assembleFileNamesTable(filenamesTable, nbFiles, buf);
+    }
+}
+
+static FileNamesTable*
+UTIL_assembleFileNamesTable2(const char** filenames, size_t tableSize, size_t tableCapacity, char* buf)
+{
+    FileNamesTable* const table = (FileNamesTable*) malloc(sizeof(*table));
+    CONTROL(table != NULL);
+    table->fileNames = filenames;
+    table->buf = buf;
+    table->tableSize = tableSize;
+    table->tableCapacity = tableCapacity;
+    return table;
+}
+
+FileNamesTable*
+UTIL_assembleFileNamesTable(const char** filenames, size_t tableSize, char* buf)
+{
+    return UTIL_assembleFileNamesTable2(filenames, tableSize, tableSize, buf);
+}
+
+void UTIL_freeFileNamesTable(FileNamesTable* table)
+{
+    if (table==NULL) return;
+    free((void*)table->fileNames);
+    free(table->buf);
+    free(table);
+}
+
+FileNamesTable* UTIL_allocateFileNamesTable(size_t tableSize)
+{
+    const char** const fnTable = (const char**)malloc(tableSize * sizeof(*fnTable));
+    FileNamesTable* fnt;
+    if (fnTable==NULL) return NULL;
+    fnt = UTIL_assembleFileNamesTable(fnTable, tableSize, NULL);
+    fnt->tableSize = 0;   /* the table is empty */
+    return fnt;
+}
+
+void UTIL_refFilename(FileNamesTable* fnt, const char* filename)
+{
+    assert(fnt->tableSize < fnt->tableCapacity);
+    fnt->fileNames[fnt->tableSize] = filename;
+    fnt->tableSize++;
+}
+
+static size_t getTotalTableSize(FileNamesTable* table)
+{
+    size_t fnb = 0, totalSize = 0;
+    for(fnb = 0 ; fnb < table->tableSize && table->fileNames[fnb] ; ++fnb) {
+        totalSize += strlen(table->fileNames[fnb]) + 1; /* +1 to add '\0' at the end of each fileName */
+    }
+    return totalSize;
+}
+
+FileNamesTable*
+UTIL_mergeFileNamesTable(FileNamesTable* table1, FileNamesTable* table2)
+{
+    unsigned newTableIdx = 0;
+    size_t pos = 0;
+    size_t newTotalTableSize;
+    char* buf;
+
+    FileNamesTable* const newTable = UTIL_assembleFileNamesTable(NULL, 0, NULL);
+    CONTROL( newTable != NULL );
+
+    newTotalTableSize = getTotalTableSize(table1) + getTotalTableSize(table2);
+
+    buf = (char*) calloc(newTotalTableSize, sizeof(*buf));
+    CONTROL ( buf != NULL );
+
+    newTable->buf = buf;
+    newTable->tableSize = table1->tableSize + table2->tableSize;
+    newTable->fileNames = (const char **) calloc(newTable->tableSize, sizeof(*(newTable->fileNames)));
+    CONTROL ( newTable->fileNames != NULL );
+
+    {   unsigned idx1;
+        for( idx1=0 ; (idx1 < table1->tableSize) && table1->fileNames[idx1] && (pos < newTotalTableSize); ++idx1, ++newTableIdx) {
+            size_t const curLen = strlen(table1->fileNames[idx1]);
+            memcpy(buf+pos, table1->fileNames[idx1], curLen);
+            assert(newTableIdx <= newTable->tableSize);
+            newTable->fileNames[newTableIdx] = buf+pos;
+            pos += curLen+1;
+    }   }
+
+    {   unsigned idx2;
+        for( idx2=0 ; (idx2 < table2->tableSize) && table2->fileNames[idx2] && (pos < newTotalTableSize) ; ++idx2, ++newTableIdx) {
+            size_t const curLen = strlen(table2->fileNames[idx2]);
+            memcpy(buf+pos, table2->fileNames[idx2], curLen);
+            assert(newTableIdx <= newTable->tableSize);
+            newTable->fileNames[newTableIdx] = buf+pos;
+            pos += curLen+1;
+    }   }
+    assert(pos <= newTotalTableSize);
+    newTable->tableSize = newTableIdx;
+
+    UTIL_freeFileNamesTable(table1);
+    UTIL_freeFileNamesTable(table2);
+
+    return newTable;
+}
+
+#ifdef _WIN32
+static int UTIL_prepareFileList(const char* dirName,
+                                char** bufStart, size_t* pos,
+                                char** bufEnd, int followLinks)
+{
+    char* path;
+    size_t dirLength, pathLength;
+    int nbFiles = 0;
+    WIN32_FIND_DATAA cFile;
+    HANDLE hFile;
+
+    dirLength = strlen(dirName);
+    path = (char*) malloc(dirLength + 3);
+    if (!path) return 0;
+
+    memcpy(path, dirName, dirLength);
+    path[dirLength] = '\\';
+    path[dirLength+1] = '*';
+    path[dirLength+2] = 0;
+
+    hFile=FindFirstFileA(path, &cFile);
+    if (hFile == INVALID_HANDLE_VALUE) {
+        UTIL_DISPLAYLEVEL(1, "Cannot open directory '%s'\n", dirName);
+        return 0;
+    }
+    free(path);
+
+    do {
+        size_t const fnameLength = strlen(cFile.cFileName);
+        path = (char*) malloc(dirLength + fnameLength + 2);
+        if (!path) { FindClose(hFile); return 0; }
+        memcpy(path, dirName, dirLength);
+        path[dirLength] = '\\';
+        memcpy(path+dirLength+1, cFile.cFileName, fnameLength);
+        pathLength = dirLength+1+fnameLength;
+        path[pathLength] = 0;
+        if (cFile.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) {
+            if ( strcmp (cFile.cFileName, "..") == 0
+              || strcmp (cFile.cFileName, ".") == 0 )
+                continue;
+            /* Recursively call "UTIL_prepareFileList" with the new path. */
+            nbFiles += UTIL_prepareFileList(path, bufStart, pos, bufEnd, followLinks);
+            if (*bufStart == NULL) { free(path); FindClose(hFile); return 0; }
+        } else if ( (cFile.dwFileAttributes & FILE_ATTRIBUTE_NORMAL)
+                 || (cFile.dwFileAttributes & FILE_ATTRIBUTE_ARCHIVE)
+                 || (cFile.dwFileAttributes & FILE_ATTRIBUTE_COMPRESSED) ) {
+            if (*bufStart + *pos + pathLength >= *bufEnd) {
+                ptrdiff_t const newListSize = (*bufEnd - *bufStart) + LIST_SIZE_INCREASE;
+                *bufStart = (char*)UTIL_realloc(*bufStart, newListSize);
+                if (*bufStart == NULL) { free(path); FindClose(hFile); return 0; }
+                *bufEnd = *bufStart + newListSize;
+            }
+            if (*bufStart + *pos + pathLength < *bufEnd) {
+                memcpy(*bufStart + *pos, path, pathLength+1 /* include final \0 */);
+                *pos += pathLength + 1;
+                nbFiles++;
+        }   }
+        free(path);
+    } while (FindNextFileA(hFile, &cFile));
+
+    FindClose(hFile);
+    return nbFiles;
+}
+
+#elif defined(__linux__) || (PLATFORM_POSIX_VERSION >= 200112L)  /* opendir, readdir require POSIX.1-2001 */
+
+static int UTIL_prepareFileList(const char *dirName,
+                                char** bufStart, size_t* pos,
+                                char** bufEnd, int followLinks)
+{
+    DIR* dir;
+    struct dirent * entry;
+    size_t dirLength;
+    int nbFiles = 0;
+
+    if (!(dir = opendir(dirName))) {
+        UTIL_DISPLAYLEVEL(1, "Cannot open directory '%s': %s\n", dirName, strerror(errno));
+        return 0;
+    }
+
+    dirLength = strlen(dirName);
+    errno = 0;
+    while ((entry = readdir(dir)) != NULL) {
+        char* path;
+        size_t fnameLength, pathLength;
+        if (strcmp (entry->d_name, "..") == 0 ||
+            strcmp (entry->d_name, ".") == 0) continue;
+        fnameLength = strlen(entry->d_name);
+        path = (char*) malloc(dirLength + fnameLength + 2);
+        if (!path) { closedir(dir); return 0; }
+        memcpy(path, dirName, dirLength);
+
+        path[dirLength] = '/';
+        memcpy(path+dirLength+1, entry->d_name, fnameLength);
+        pathLength = dirLength+1+fnameLength;
+        path[pathLength] = 0;
+
+        if (!followLinks && UTIL_isLink(path)) {
+            UTIL_DISPLAYLEVEL(2, "Warning : %s is a symbolic link, ignoring\n", path);
+            free(path);
+            continue;
+        }
+
+        if (UTIL_isDirectory(path)) {
+            nbFiles += UTIL_prepareFileList(path, bufStart, pos, bufEnd, followLinks);  /* Recursively call "UTIL_prepareFileList" with the new path. */
+            if (*bufStart == NULL) { free(path); closedir(dir); return 0; }
+        } else {
+            if (*bufStart + *pos + pathLength >= *bufEnd) {
+                ptrdiff_t newListSize = (*bufEnd - *bufStart) + LIST_SIZE_INCREASE;
+                assert(newListSize >= 0);
+                *bufStart = (char*)UTIL_realloc(*bufStart, (size_t)newListSize);
+                *bufEnd = *bufStart + newListSize;
+                if (*bufStart == NULL) { free(path); closedir(dir); return 0; }
+            }
+            if (*bufStart + *pos + pathLength < *bufEnd) {
+                memcpy(*bufStart + *pos, path, pathLength + 1);  /* with final \0 */
+                *pos += pathLength + 1;
+                nbFiles++;
+        }   }
+        free(path);
+        errno = 0; /* clear errno after UTIL_isDirectory, UTIL_prepareFileList */
+    }
+
+    if (errno != 0) {
+        UTIL_DISPLAYLEVEL(1, "readdir(%s) error: %s \n", dirName, strerror(errno));
+        free(*bufStart);
+        *bufStart = NULL;
+    }
+    closedir(dir);
+    return nbFiles;
+}
+
+#else
+
+static int UTIL_prepareFileList(const char *dirName,
+                                char** bufStart, size_t* pos,
+                                char** bufEnd, int followLinks)
+{
+    (void)bufStart; (void)bufEnd; (void)pos; (void)followLinks;
+    UTIL_DISPLAYLEVEL(1, "Directory %s ignored (compiled without _WIN32 or _POSIX_C_SOURCE) \n", dirName);
+    return 0;
+}
+
+#endif /* #ifdef _WIN32 */
+
+int UTIL_isCompressedFile(const char *inputName, const char *extensionList[])
+{
+  const char* ext = UTIL_getFileExtension(inputName);
+  while(*extensionList!=NULL)
+  {
+    const int isCompressedExtension = strcmp(ext,*extensionList);
+    if(isCompressedExtension==0)
+      return 1;
+    ++extensionList;
+  }
+   return 0;
+}
+
+/*Utility function to get file extension from file */
+const char* UTIL_getFileExtension(const char* infilename)
+{
+   const char* extension = strrchr(infilename, '.');
+   if(!extension || extension==infilename) return "";
+   return extension;
+}
+
+
+FileNamesTable*
+UTIL_createExpandedFNT(const char** inputNames, size_t nbIfns, int followLinks)
+{
+    unsigned nbFiles;
+    char* buf = (char*)malloc(LIST_SIZE_INCREASE);
+    char* bufend = buf + LIST_SIZE_INCREASE;
+
+    if (!buf) return NULL;
+
+    {   size_t ifnNb, pos;
+        for (ifnNb=0, pos=0, nbFiles=0; ifnNb<nbIfns; ifnNb++) {
+            if (!UTIL_isDirectory(inputNames[ifnNb])) {
+                size_t const len = strlen(inputNames[ifnNb]);
+                if (buf + pos + len >= bufend) {
+                    ptrdiff_t newListSize = (bufend - buf) + LIST_SIZE_INCREASE;
+                    assert(newListSize >= 0);
+                    buf = (char*)UTIL_realloc(buf, (size_t)newListSize);
+                    if (!buf) return NULL;
+                    bufend = buf + newListSize;
+                }
+                if (buf + pos + len < bufend) {
+                    memcpy(buf+pos, inputNames[ifnNb], len+1);  /* including final \0 */
+                    pos += len + 1;
+                    nbFiles++;
+                }
+            } else {
+                nbFiles += (unsigned)UTIL_prepareFileList(inputNames[ifnNb], &buf, &pos, &bufend, followLinks);
+                if (buf == NULL) return NULL;
+    }   }   }
+
+    /* note : even if nbFiles==0, function returns a valid, though empty, FileNamesTable* object */
+
+    {   size_t ifnNb, pos;
+        size_t const fntCapacity = nbFiles + 1;  /* minimum 1, allows adding one reference, typically stdin */
+        const char** const fileNamesTable = (const char**)malloc(fntCapacity * sizeof(*fileNamesTable));
+        if (!fileNamesTable) { free(buf); return NULL; }
+
+        for (ifnNb = 0, pos = 0; ifnNb < nbFiles; ifnNb++) {
+            fileNamesTable[ifnNb] = buf + pos;
+            if (buf + pos > bufend) { free(buf); free((void*)fileNamesTable); return NULL; }
+            pos += strlen(fileNamesTable[ifnNb]) + 1;
+        }
+        return UTIL_assembleFileNamesTable2(fileNamesTable, nbFiles, fntCapacity, buf);
+    }
+}
+
+
+void UTIL_expandFNT(FileNamesTable** fnt, int followLinks)
+{
+    FileNamesTable* const newFNT = UTIL_createExpandedFNT((*fnt)->fileNames, (*fnt)->tableSize, followLinks);
+    CONTROL(newFNT != NULL);
+    UTIL_freeFileNamesTable(*fnt);
+    *fnt = newFNT;
+}
+
+FileNamesTable* UTIL_createFNT_fromROTable(const char** filenames, size_t nbFilenames)
+{
+    size_t const sizeof_FNTable = nbFilenames * sizeof(*filenames);
+    const char** const newFNTable = (const char**)malloc(sizeof_FNTable);
+    if (newFNTable==NULL) return NULL;
+    memcpy((void*)newFNTable, filenames, sizeof_FNTable);  /* void* : mitigate a Visual compiler bug or limitation */
+    return UTIL_assembleFileNamesTable(newFNTable, nbFilenames, NULL);
+}
+
+
+/*-****************************************
+*  count the number of physical cores
+******************************************/
+
+#if defined(_WIN32) || defined(WIN32)
+
+#include <windows.h>
+
+typedef BOOL(WINAPI* LPFN_GLPI)(PSYSTEM_LOGICAL_PROCESSOR_INFORMATION, PDWORD);
+
+int UTIL_countPhysicalCores(void)
+{
+    static int numPhysicalCores = 0;
+    if (numPhysicalCores != 0) return numPhysicalCores;
+
+    {   LPFN_GLPI glpi;
+        BOOL done = FALSE;
+        PSYSTEM_LOGICAL_PROCESSOR_INFORMATION buffer = NULL;
+        PSYSTEM_LOGICAL_PROCESSOR_INFORMATION ptr = NULL;
+        DWORD returnLength = 0;
+        size_t byteOffset = 0;
+
+#if defined(_MSC_VER)
+/* Visual Studio does not like the following cast */
+#   pragma warning( disable : 4054 )  /* conversion from function ptr to data ptr */
+#   pragma warning( disable : 4055 )  /* conversion from data ptr to function ptr */
+#endif
+        glpi = (LPFN_GLPI)(void*)GetProcAddress(GetModuleHandle(TEXT("kernel32")),
+                                               "GetLogicalProcessorInformation");
+
+        if (glpi == NULL) {
+            goto failed;
+        }
+
+        while(!done) {
+            DWORD rc = glpi(buffer, &returnLength);
+            if (FALSE == rc) {
+                if (GetLastError() == ERROR_INSUFFICIENT_BUFFER) {
+                    if (buffer)
+                        free(buffer);
+                    buffer = (PSYSTEM_LOGICAL_PROCESSOR_INFORMATION)malloc(returnLength);
+
+                    if (buffer == NULL) {
+                        perror("zstd");
+                        exit(1);
+                    }
+                } else {
+                    /* some other error */
+                    goto failed;
+                }
+            } else {
+                done = TRUE;
+        }   }
+
+        ptr = buffer;
+
+        while (byteOffset + sizeof(SYSTEM_LOGICAL_PROCESSOR_INFORMATION) <= returnLength) {
+
+            if (ptr->Relationship == RelationProcessorCore) {
+                numPhysicalCores++;
+            }
+
+            ptr++;
+            byteOffset += sizeof(SYSTEM_LOGICAL_PROCESSOR_INFORMATION);
+        }
+
+        free(buffer);
+
+        return numPhysicalCores;
+    }
+
+failed:
+    /* try to fall back on GetSystemInfo */
+    {   SYSTEM_INFO sysinfo;
+        GetSystemInfo(&sysinfo);
+        numPhysicalCores = sysinfo.dwNumberOfProcessors;
+        if (numPhysicalCores == 0) numPhysicalCores = 1; /* just in case */
+    }
+    return numPhysicalCores;
+}
+
+#elif defined(__APPLE__)
+
+#include <sys/sysctl.h>
+
+/* Use apple-provided syscall
+ * see: man 3 sysctl */
+int UTIL_countPhysicalCores(void)
+{
+    static S32 numPhysicalCores = 0; /* apple specifies int32_t */
+    if (numPhysicalCores != 0) return numPhysicalCores;
+
+    {   size_t size = sizeof(S32);
+        int const ret = sysctlbyname("hw.physicalcpu", &numPhysicalCores, &size, NULL, 0);
+        if (ret != 0) {
+            if (errno == ENOENT) {
+                /* entry not present, fall back on 1 */
+                numPhysicalCores = 1;
+            } else {
+                perror("zstd: can't get number of physical cpus");
+                exit(1);
+            }
+        }
+
+        return numPhysicalCores;
+    }
+}
+
+#elif defined(__linux__)
+
+/* parse /proc/cpuinfo
+ * siblings / cpu cores should give hyperthreading ratio
+ * otherwise fall back on sysconf */
+int UTIL_countPhysicalCores(void)
+{
+    static int numPhysicalCores = 0;
+
+    if (numPhysicalCores != 0) return numPhysicalCores;
+
+    numPhysicalCores = (int)sysconf(_SC_NPROCESSORS_ONLN);
+    if (numPhysicalCores == -1) {
+        /* value not queryable, fall back on 1 */
+        return numPhysicalCores = 1;
+    }
+
+    /* try to determine if there's hyperthreading */
+    {   FILE* const cpuinfo = fopen("/proc/cpuinfo", "r");
+#define BUF_SIZE 80
+        char buff[BUF_SIZE];
+
+        int siblings = 0;
+        int cpu_cores = 0;
+        int ratio = 1;
+
+        if (cpuinfo == NULL) {
+            /* fall back on the sysconf value */
+            return numPhysicalCores;
+        }
+
+        /* assume the cpu cores/siblings values will be constant across all
+         * present processors */
+        while (!feof(cpuinfo)) {
+            if (fgets(buff, BUF_SIZE, cpuinfo) != NULL) {
+                if (strncmp(buff, "siblings", 8) == 0) {
+                    const char* const sep = strchr(buff, ':');
+                    if (sep == NULL || *sep == '\0') {
+                        /* formatting was broken? */
+                        goto failed;
+                    }
+
+                    siblings = atoi(sep + 1);
+                }
+                if (strncmp(buff, "cpu cores", 9) == 0) {
+                    const char* const sep = strchr(buff, ':');
+                    if (sep == NULL || *sep == '\0') {
+                        /* formatting was broken? */
+                        goto failed;
+                    }
+
+                    cpu_cores = atoi(sep + 1);
+                }
+            } else if (ferror(cpuinfo)) {
+                /* fall back on the sysconf value */
+                goto failed;
+        }   }
+        if (siblings && cpu_cores) {
+            ratio = siblings / cpu_cores;
+        }
+failed:
+        fclose(cpuinfo);
+        return numPhysicalCores = numPhysicalCores / ratio;
+    }
+}
+
+#elif defined(__FreeBSD__)
+
+#include <sys/param.h>
+#include <sys/sysctl.h>
+
+/* Use physical core sysctl when available
+ * see: man 4 smp, man 3 sysctl */
+int UTIL_countPhysicalCores(void)
+{
+    static int numPhysicalCores = 0; /* freebsd sysctl is native int sized */
+    if (numPhysicalCores != 0) return numPhysicalCores;
+
+#if __FreeBSD_version >= 1300008
+    {   size_t size = sizeof(numPhysicalCores);
+        int ret = sysctlbyname("kern.smp.cores", &numPhysicalCores, &size, NULL, 0);
+        if (ret == 0) return numPhysicalCores;
+        if (errno != ENOENT) {
+            perror("zstd: can't get number of physical cpus");
+            exit(1);
+        }
+        /* sysctl not present, fall through to older sysconf method */
+    }
+#endif
+
+    numPhysicalCores = (int)sysconf(_SC_NPROCESSORS_ONLN);
+    if (numPhysicalCores == -1) {
+        /* value not queryable, fall back on 1 */
+        numPhysicalCores = 1;
+    }
+    return numPhysicalCores;
+}
+
+#elif defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) || defined(__CYGWIN__)
+
+/* Use POSIX sysconf
+ * see: man 3 sysconf */
+int UTIL_countPhysicalCores(void)
+{
+    static int numPhysicalCores = 0;
+
+    if (numPhysicalCores != 0) return numPhysicalCores;
+
+    numPhysicalCores = (int)sysconf(_SC_NPROCESSORS_ONLN);
+    if (numPhysicalCores == -1) {
+        /* value not queryable, fall back on 1 */
+        return numPhysicalCores = 1;
+    }
+    return numPhysicalCores;
+}
+
+#else
+
+int UTIL_countPhysicalCores(void)
+{
+    /* assume 1 */
+    return 1;
+}
+
+#endif
+
+#if defined (__cplusplus)
+}
+#endif
diff --git a/src/zstd/programs/util.h b/src/zstd/programs/util.h
new file mode 100644
index 000000000..8e187e4f2
--- /dev/null
+++ b/src/zstd/programs/util.h
@@ -0,0 +1,235 @@
+/*
+ * Copyright (c) 2016-2020, Przemyslaw Skibinski, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
+ */
+
+#ifndef UTIL_H_MODULE
+#define UTIL_H_MODULE
+
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
+
+/*-****************************************
+*  Dependencies
+******************************************/
+#include "platform.h"     /* PLATFORM_POSIX_VERSION, ZSTD_NANOSLEEP_SUPPORT, ZSTD_SETPRIORITY_SUPPORT */
+#include <stddef.h>       /* size_t, ptrdiff_t */
+#include <sys/types.h>    /* stat, utime */
+#include <sys/stat.h>     /* stat, chmod */
+#include "../lib/common/mem.h"          /* U64 */
+
+
+/*-************************************************************
+* Avoid fseek()'s 2GiB barrier with MSVC, macOS, *BSD, MinGW
+***************************************************************/
+#if defined(_MSC_VER) && (_MSC_VER >= 1400)
+#  define UTIL_fseek _fseeki64
+#elif !defined(__64BIT__) && (PLATFORM_POSIX_VERSION >= 200112L) /* No point defining Large file for 64 bit */
+#  define UTIL_fseek fseeko
+#elif defined(__MINGW32__) && defined(__MSVCRT__) && !defined(__STRICT_ANSI__) && !defined(__NO_MINGW_LFS)
+#  define UTIL_fseek fseeko64
+#else
+#  define UTIL_fseek fseek
+#endif
+
+
+/*-*************************************************
+*  Sleep & priority functions: Windows - Posix - others
+***************************************************/
+#if defined(_WIN32)
+#  include <windows.h>
+#  define SET_REALTIME_PRIORITY SetPriorityClass(GetCurrentProcess(), REALTIME_PRIORITY_CLASS)
+#  define UTIL_sleep(s) Sleep(1000*s)
+#  define UTIL_sleepMilli(milli) Sleep(milli)
+
+#elif PLATFORM_POSIX_VERSION > 0 /* Unix-like operating system */
+#  include <unistd.h>   /* sleep */
+#  define UTIL_sleep(s) sleep(s)
+#  if ZSTD_NANOSLEEP_SUPPORT   /* necessarily defined in platform.h */
+#      define UTIL_sleepMilli(milli) { struct timespec t; t.tv_sec=0; t.tv_nsec=milli*1000000ULL; nanosleep(&t, NULL); }
+#  else
+#      define UTIL_sleepMilli(milli) /* disabled */
+#  endif
+#  if ZSTD_SETPRIORITY_SUPPORT
+#    include <sys/resource.h> /* setpriority */
+#    define SET_REALTIME_PRIORITY setpriority(PRIO_PROCESS, 0, -20)
+#  else
+#    define SET_REALTIME_PRIORITY /* disabled */
+#  endif
+
+#else  /* unknown non-unix operating systen */
+#  define UTIL_sleep(s)          /* disabled */
+#  define UTIL_sleepMilli(milli) /* disabled */
+#  define SET_REALTIME_PRIORITY  /* disabled */
+#endif
+
+
+/*-****************************************
+*  Compiler specifics
+******************************************/
+#if defined(__INTEL_COMPILER)
+#  pragma warning(disable : 177)    /* disable: message #177: function was declared but never referenced, useful with UTIL_STATIC */
+#endif
+#if defined(__GNUC__)
+#  define UTIL_STATIC static __attribute__((unused))
+#elif defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
+#  define UTIL_STATIC static inline
+#elif defined(_MSC_VER)
+#  define UTIL_STATIC static __inline
+#else
+#  define UTIL_STATIC static  /* this version may generate warnings for unused static functions; disable the relevant warning */
+#endif
+
+
+/*-****************************************
+*  Console log
+******************************************/
+extern int g_utilDisplayLevel;
+
+
+/*-****************************************
+*  File functions
+******************************************/
+#if defined(_MSC_VER)
+    typedef struct __stat64 stat_t;
+    typedef int mode_t;
+#else
+    typedef struct stat stat_t;
+#endif
+
+
+int UTIL_fileExist(const char* filename);
+int UTIL_isRegularFile(const char* infilename);
+int UTIL_isDirectory(const char* infilename);
+int UTIL_isSameFile(const char* file1, const char* file2);
+int UTIL_isCompressedFile(const char* infilename, const char *extensionList[]);
+int UTIL_isLink(const char* infilename);
+int UTIL_isFIFO(const char* infilename);
+
+#define UTIL_FILESIZE_UNKNOWN  ((U64)(-1))
+U64 UTIL_getFileSize(const char* infilename);
+U64 UTIL_getTotalFileSize(const char* const * fileNamesTable, unsigned nbFiles);
+int UTIL_getFileStat(const char* infilename, stat_t* statbuf);
+int UTIL_setFileStat(const char* filename, stat_t* statbuf);
+int UTIL_chmod(char const* filename, mode_t permissions);   /*< like chmod, but avoid changing permission of /dev/null */
+int UTIL_compareStr(const void *p1, const void *p2);
+const char* UTIL_getFileExtension(const char* infilename);
+
+
+/*-****************************************
+ *  Lists of Filenames
+ ******************************************/
+
+typedef struct
+{   const char** fileNames;
+    char* buf;            /* fileNames are stored in this buffer (or are read-only) */
+    size_t tableSize;     /* nb of fileNames */
+    size_t tableCapacity;
+} FileNamesTable;
+
+/*! UTIL_createFileNamesTable_fromFileName() :
+ *  read filenames from @inputFileName, and store them into returned object.
+ * @return : a FileNamesTable*, or NULL in case of error (ex: @inputFileName doesn't exist).
+ *  Note: inputFileSize must be less than 50MB
+ */
+FileNamesTable*
+UTIL_createFileNamesTable_fromFileName(const char* inputFileName);
+
+/*! UTIL_assembleFileNamesTable() :
+ *  This function takes ownership of its arguments, @filenames and @buf,
+ *  and store them inside the created object.
+ *  note : this function never fails,
+ *         it will rather exit() the program if internal allocation fails.
+ * @return : resulting FileNamesTable* object.
+ */
+FileNamesTable*
+UTIL_assembleFileNamesTable(const char** filenames, size_t tableSize, char* buf);
+
+/*! UTIL_freeFileNamesTable() :
+ *  This function is compatible with NULL argument and never fails.
+ */
+void UTIL_freeFileNamesTable(FileNamesTable* table);
+
+/*! UTIL_mergeFileNamesTable():
+ * @return : FileNamesTable*, concatenation of @table1 and @table2
+ *  note: @table1 and @table2 are consumed (freed) by this operation
+ */
+FileNamesTable*
+UTIL_mergeFileNamesTable(FileNamesTable* table1, FileNamesTable* table2);
+
+
+/*! UTIL_expandFNT() :
+ *  read names from @fnt, and expand those corresponding to directories
+ *  update @fnt, now containing only file names,
+ * @return : 0 in case of success, 1 if error
+ *  note : in case of error, @fnt[0] is NULL
+ */
+void UTIL_expandFNT(FileNamesTable** fnt, int followLinks);
+
+/*! UTIL_createFNT_fromROTable() :
+ *  copy the @filenames pointer table inside the returned object.
+ *  The names themselves are still stored in their original buffer, which must outlive the object.
+ * @return : a FileNamesTable* object,
+ *        or NULL in case of error
+ */
+FileNamesTable*
+UTIL_createFNT_fromROTable(const char** filenames, size_t nbFilenames);
+
+/*! UTIL_allocateFileNamesTable() :
+ *  Allocates a table of const char*, to insert read-only names later on.
+ *  The created FileNamesTable* doesn't hold a buffer.
+ * @return : FileNamesTable*, or NULL, if allocation fails.
+ */
+FileNamesTable* UTIL_allocateFileNamesTable(size_t tableSize);
+
+
+/*! UTIL_refFilename() :
+ *  Add a reference to read-only name into @fnt table.
+ *  As @filename is only referenced, its lifetime must outlive @fnt.
+ *  Internal table must be large enough to reference a new member,
+ *  otherwise its UB (protected by an `assert()`).
+ */
+void UTIL_refFilename(FileNamesTable* fnt, const char* filename);
+
+
+/* UTIL_createExpandedFNT() is only active if UTIL_HAS_CREATEFILELIST is defined.
+ * Otherwise, UTIL_createExpandedFNT() is a shell function which does nothing
+ * apart from displaying a warning message.
+ */
+#ifdef _WIN32
+#  define UTIL_HAS_CREATEFILELIST
+#elif defined(__linux__) || (PLATFORM_POSIX_VERSION >= 200112L)  /* opendir, readdir require POSIX.1-2001 */
+#  define UTIL_HAS_CREATEFILELIST
+#else
+   /* do not define UTIL_HAS_CREATEFILELIST */
+#endif
+
+/*! UTIL_createExpandedFNT() :
+ *  read names from @filenames, and expand those corresponding to directories.
+ *  links are followed or not depending on @followLinks directive.
+ * @return : an expanded FileNamesTable*, where each name is a file
+ *        or NULL in case of error
+ */
+FileNamesTable*
+UTIL_createExpandedFNT(const char** filenames, size_t nbFilenames, int followLinks);
+
+
+/*-****************************************
+ *  System
+ ******************************************/
+
+int UTIL_countPhysicalCores(void);
+
+
+#if defined (__cplusplus)
+}
+#endif
+
+#endif /* UTIL_H_MODULE */
diff --git a/src/zstd/programs/windres/verrsrc.h b/src/zstd/programs/windres/verrsrc.h
new file mode 100644
index 000000000..98156480f
--- /dev/null
+++ b/src/zstd/programs/windres/verrsrc.h
@@ -0,0 +1,17 @@
+/*
+ * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
+ */
+/* minimal set of defines required to generate zstd.res from zstd.rc */
+
+#define VS_VERSION_INFO         1
+
+#define VS_FFI_FILEFLAGSMASK    0x0000003FL
+#define VOS_NT_WINDOWS32        0x00040004L
+#define VFT_DLL                 0x00000002L
+#define VFT2_UNKNOWN            0x00000000L
diff --git a/src/zstd/programs/windres/zstd.rc b/src/zstd/programs/windres/zstd.rc
new file mode 100644
index 000000000..f5e404730
--- /dev/null
+++ b/src/zstd/programs/windres/zstd.rc
@@ -0,0 +1,51 @@
+// Microsoft Visual C++ generated resource script.
+//
+
+#include "zstd.h" /* ZSTD_VERSION_STRING */
+#define APSTUDIO_READONLY_SYMBOLS
+#include "verrsrc.h"
+#undef APSTUDIO_READONLY_SYMBOLS
+
+
+#if !defined(AFX_RESOURCE_DLL) || defined(AFX_TARG_ENU)
+LANGUAGE 9, 1
+
+/////////////////////////////////////////////////////////////////////////////
+//
+// Version
+//
+
+VS_VERSION_INFO     VERSIONINFO
+  FILEVERSION       ZSTD_VERSION_MAJOR,ZSTD_VERSION_MINOR,ZSTD_VERSION_RELEASE,0
+  PRODUCTVERSION    ZSTD_VERSION_MAJOR,ZSTD_VERSION_MINOR,ZSTD_VERSION_RELEASE,0
+ FILEFLAGSMASK VS_FFI_FILEFLAGSMASK
+#ifdef _DEBUG
+ FILEFLAGS VS_FF_DEBUG
+#else
+ FILEFLAGS 0x0L
+#endif
+ FILEOS VOS_NT_WINDOWS32
+ FILETYPE VFT_DLL
+ FILESUBTYPE VFT2_UNKNOWN
+BEGIN
+    BLOCK "StringFileInfo"
+    BEGIN
+        BLOCK "040904B0"
+        BEGIN
+            VALUE "CompanyName", "Yann Collet, Facebook, Inc."
+            VALUE "FileDescription", "Zstandard - Fast and efficient compression algorithm"
+            VALUE "FileVersion", ZSTD_VERSION_STRING
+            VALUE "InternalName", "zstd.exe"
+            VALUE "LegalCopyright", "Copyright (c) 2013-present, Yann Collet, Facebook, Inc."
+            VALUE "OriginalFilename", "zstd.exe"
+            VALUE "ProductName", "Zstandard"
+            VALUE "ProductVersion", ZSTD_VERSION_STRING
+        END
+    END
+    BLOCK "VarFileInfo"
+    BEGIN
+        VALUE "Translation", 0x0409, 1200
+    END
+END
+
+#endif
diff --git a/src/zstd/programs/windres/zstd32.res b/src/zstd/programs/windres/zstd32.res
new file mode 100644
index 000000000..9984215b5
--- /dev/null
+++ b/src/zstd/programs/windres/zstd32.res
diff --git a/src/zstd/programs/windres/zstd64.res b/src/zstd/programs/windres/zstd64.res
new file mode 100644
index 000000000..615f38944
--- /dev/null
+++ b/src/zstd/programs/windres/zstd64.res
diff --git a/src/zstd/programs/zstd.1 b/src/zstd/programs/zstd.1
new file mode 100644
index 000000000..9ba0b4fa4
--- /dev/null
+++ b/src/zstd/programs/zstd.1
@@ -0,0 +1,476 @@
+.
+.TH "ZSTD" "1" "May 2020" "zstd 1.4.5" "User Commands"
+.
+.SH "NAME"
+\fBzstd\fR \- zstd, zstdmt, unzstd, zstdcat \- Compress or decompress \.zst files
+.
+.SH "SYNOPSIS"
+\fBzstd\fR [\fIOPTIONS\fR] [\-|\fIINPUT\-FILE\fR] [\-o \fIOUTPUT\-FILE\fR]
+.
+.P
+\fBzstdmt\fR is equivalent to \fBzstd \-T0\fR
+.
+.P
+\fBunzstd\fR is equivalent to \fBzstd \-d\fR
+.
+.P
+\fBzstdcat\fR is equivalent to \fBzstd \-dcf\fR
+.
+.SH "DESCRIPTION"
+\fBzstd\fR is a fast lossless compression algorithm and data compression tool, with command line syntax similar to \fBgzip (1)\fR and \fBxz (1)\fR\. It is based on the \fBLZ77\fR family, with further FSE & huff0 entropy stages\. \fBzstd\fR offers highly configurable compression speed, with fast modes at > 200 MB/s per core, and strong modes nearing lzma compression ratios\. It also features a very fast decoder, with speeds > 500 MB/s per core\.
+.
+.P
+\fBzstd\fR command line syntax is generally similar to gzip, but features the following differences :
+.
+.IP "\(bu" 4
+Source files are preserved by default\. It\'s possible to remove them automatically by using the \fB\-\-rm\fR command\.
+.
+.IP "\(bu" 4
+When compressing a single file, \fBzstd\fR displays progress notifications and result summary by default\. Use \fB\-q\fR to turn them off\.
+.
+.IP "\(bu" 4
+\fBzstd\fR does not accept input from console, but it properly accepts \fBstdin\fR when it\'s not the console\.
+.
+.IP "\(bu" 4
+\fBzstd\fR displays a short help page when command line is an error\. Use \fB\-q\fR to turn it off\.
+.
+.IP "" 0
+.
+.P
+\fBzstd\fR compresses or decompresses each \fIfile\fR according to the selected operation mode\. If no \fIfiles\fR are given or \fIfile\fR is \fB\-\fR, \fBzstd\fR reads from standard input and writes the processed data to standard output\. \fBzstd\fR will refuse to write compressed data to standard output if it is a terminal : it will display an error message and skip the \fIfile\fR\. Similarly, \fBzstd\fR will refuse to read compressed data from standard input if it is a terminal\.
+.
+.P
+Unless \fB\-\-stdout\fR or \fB\-o\fR is specified, \fIfiles\fR are written to a new file whose name is derived from the source \fIfile\fR name:
+.
+.IP "\(bu" 4
+When compressing, the suffix \fB\.zst\fR is appended to the source filename to get the target filename\.
+.
+.IP "\(bu" 4
+When decompressing, the \fB\.zst\fR suffix is removed from the source filename to get the target filename
+.
+.IP "" 0
+.
+.SS "Concatenation with \.zst files"
+It is possible to concatenate \fB\.zst\fR files as is\. \fBzstd\fR will decompress such files as if they were a single \fB\.zst\fR file\.
+.
+.SH "OPTIONS"
+.
+.SS "Integer suffixes and special values"
+In most places where an integer argument is expected, an optional suffix is supported to easily indicate large integers\. There must be no space between the integer and the suffix\.
+.
+.TP
+\fBKiB\fR
+Multiply the integer by 1,024 (2^10)\. \fBKi\fR, \fBK\fR, and \fBKB\fR are accepted as synonyms for \fBKiB\fR\.
+.
+.TP
+\fBMiB\fR
+Multiply the integer by 1,048,576 (2^20)\. \fBMi\fR, \fBM\fR, and \fBMB\fR are accepted as synonyms for \fBMiB\fR\.
+.
+.SS "Operation mode"
+If multiple operation mode options are given, the last one takes effect\.
+.
+.TP
+\fB\-z\fR, \fB\-\-compress\fR
+Compress\. This is the default operation mode when no operation mode option is specified and no other operation mode is implied from the command name (for example, \fBunzstd\fR implies \fB\-\-decompress\fR)\.
+.
+.TP
+\fB\-d\fR, \fB\-\-decompress\fR, \fB\-\-uncompress\fR
+Decompress\.
+.
+.TP
+\fB\-t\fR, \fB\-\-test\fR
+Test the integrity of compressed \fIfiles\fR\. This option is equivalent to \fB\-\-decompress \-\-stdout\fR except that the decompressed data is discarded instead of being written to standard output\. No files are created or removed\.
+.
+.TP
+\fB\-b#\fR
+Benchmark file(s) using compression level #
+.
+.TP
+\fB\-\-train FILEs\fR
+Use FILEs as a training set to create a dictionary\. The training set should contain a lot of small files (> 100)\.
+.
+.TP
+\fB\-l\fR, \fB\-\-list\fR
+Display information related to a zstd compressed file, such as size, ratio, and checksum\. Some of these fields may not be available\. This command can be augmented with the \fB\-v\fR modifier\.
+.
+.SS "Operation modifiers"
+.
+.IP "\(bu" 4
+\fB\-#\fR: \fB#\fR compression level [1\-19] (default: 3)
+.
+.IP "\(bu" 4
+\fB\-\-fast[=#]\fR: switch to ultra\-fast compression levels\. If \fB=#\fR is not present, it defaults to \fB1\fR\. The higher the value, the faster the compression speed, at the cost of some compression ratio\. This setting overwrites compression level if one was set previously\. Similarly, if a compression level is set after \fB\-\-fast\fR, it overrides it\.
+.
+.IP "\(bu" 4
+\fB\-\-ultra\fR: unlocks high compression levels 20+ (maximum 22), using a lot more memory\. Note that decompression will also require more memory when using these levels\.
+.
+.IP "\(bu" 4
+\fB\-\-long[=#]\fR: enables long distance matching with \fB#\fR \fBwindowLog\fR, if not \fB#\fR is not present it defaults to \fB27\fR\. This increases the window size (\fBwindowLog\fR) and memory usage for both the compressor and decompressor\. This setting is designed to improve the compression ratio for files with long matches at a large distance\.
+.
+.IP
+Note: If \fBwindowLog\fR is set to larger than 27, \fB\-\-long=windowLog\fR or \fB\-\-memory=windowSize\fR needs to be passed to the decompressor\.
+.
+.IP "\(bu" 4
+\fB\-\-patch\-from=FILE\fR: Specify the file to be used as a reference point for zstd\'s diff engine\. This is effectively dictionary compression with some convenient parameter selection, namely that windowSize > srcSize\.
+.
+.IP
+Note: cannot use both this and \-D together Note: \fB\-\-long\fR mode will be automatically activated if chainLog < fileLog (fileLog being the windowLog requried to cover the whole file)\. You can also manually force it\. Node: for all levels, you can use \-\-patch\-from in \-\-single\-thread mode to improve compression ratio at the cost of speed Note: for level 19, you can get increased compression ratio at the cost of speed by specifying \fB\-\-zstd=targetLength=\fR to be something large (i\.e 4096), and by setting a large \fB\-\-zstd=chainLog=\fR
+.
+.IP "\(bu" 4
+\fB\-M#\fR, \fB\-\-memory=#\fR: Set a memory usage limit\. By default, Zstandard uses 128 MB for decompression as the maximum amount of memory the decompressor is allowed to use, but you can override this manually if need be in either direction (ie\. you can increase or decrease it)\.
+.
+.IP
+This is also used during compression when using with \-\-patch\-from=\. In this case, this parameter overrides that maximum size allowed for a dictionary\. (128 MB)\.
+.
+.IP "\(bu" 4
+\fB\-T#\fR, \fB\-\-threads=#\fR: Compress using \fB#\fR working threads (default: 1)\. If \fB#\fR is 0, attempt to detect and use the number of physical CPU cores\. In all cases, the nb of threads is capped to ZSTDMT_NBTHREADS_MAX==200\. This modifier does nothing if \fBzstd\fR is compiled without multithread support\.
+.
+.IP "\(bu" 4
+\fB\-\-single\-thread\fR: Does not spawn a thread for compression, use a single thread for both I/O and compression\. In this mode, compression is serialized with I/O, which is slightly slower\. (This is different from \fB\-T1\fR, which spawns 1 compression thread in parallel of I/O)\. This mode is the only one available when multithread support is disabled\. Single\-thread mode features lower memory usage\. Final compressed result is slightly different from \fB\-T1\fR\.
+.
+.IP "\(bu" 4
+\fB\-\-adapt[=min=#,max=#]\fR : \fBzstd\fR will dynamically adapt compression level to perceived I/O conditions\. Compression level adaptation can be observed live by using command \fB\-v\fR\. Adaptation can be constrained between supplied \fBmin\fR and \fBmax\fR levels\. The feature works when combined with multi\-threading and \fB\-\-long\fR mode\. It does not work with \fB\-\-single\-thread\fR\. It sets window size to 8 MB by default (can be changed manually, see \fBwlog\fR)\. Due to the chaotic nature of dynamic adaptation, compressed result is not reproducible\. \fInote\fR : at the time of this writing, \fB\-\-adapt\fR can remain stuck at low speed when combined with multiple worker threads (>=2)\.
+.
+.IP "\(bu" 4
+\fB\-\-stream\-size=#\fR : Sets the pledged source size of input coming from a stream\. This value must be exact, as it will be included in the produced frame header\. Incorrect stream sizes will cause an error\. This information will be used to better optimize compression parameters, resulting in better and potentially faster compression, especially for smaller source sizes\.
+.
+.IP "\(bu" 4
+\fB\-\-size\-hint=#\fR: When handling input from a stream, \fBzstd\fR must guess how large the source size will be when optimizing compression parameters\. If the stream size is relatively small, this guess may be a poor one, resulting in a higher compression ratio than expected\. This feature allows for controlling the guess when needed\. Exact guesses result in better compression ratios\. Overestimates result in slightly degraded compression ratios, while underestimates may result in significant degradation\.
+.
+.IP "\(bu" 4
+\fB\-\-rsyncable\fR : \fBzstd\fR will periodically synchronize the compression state to make the compressed file more rsync\-friendly\. There is a negligible impact to compression ratio, and the faster compression levels will see a small compression speed hit\. This feature does not work with \fB\-\-single\-thread\fR\. You probably don\'t want to use it with long range mode, since it will decrease the effectiveness of the synchronization points, but your milage may vary\.
+.
+.IP "\(bu" 4
+\fB\-D file\fR: use \fBfile\fR as Dictionary to compress or decompress FILE(s)
+.
+.IP "\(bu" 4
+\fB\-\-no\-dictID\fR: do not store dictionary ID within frame header (dictionary compression)\. The decoder will have to rely on implicit knowledge about which dictionary to use, it won\'t be able to check if it\'s correct\.
+.
+.IP "\(bu" 4
+\fB\-o file\fR: save result into \fBfile\fR (only possible with a single \fIINPUT\-FILE\fR)
+.
+.IP "\(bu" 4
+\fB\-f\fR, \fB\-\-force\fR: overwrite output without prompting, and (de)compress symbolic links
+.
+.IP "\(bu" 4
+\fB\-c\fR, \fB\-\-stdout\fR: force write to standard output, even if it is the console
+.
+.IP "\(bu" 4
+\fB\-\-[no\-]sparse\fR: enable / disable sparse FS support, to make files with many zeroes smaller on disk\. Creating sparse files may save disk space and speed up decompression by reducing the amount of disk I/O\. default: enabled when output is into a file, and disabled when output is stdout\. This setting overrides default and can force sparse mode over stdout\.
+.
+.IP "\(bu" 4
+\fB\-\-[no\-]content\-size\fR: enable / disable whether or not the original size of the file is placed in the header of the compressed file\. The default option is \-\-content\-size (meaning that the original size will be placed in the header)\.
+.
+.IP "\(bu" 4
+\fB\-\-rm\fR: remove source file(s) after successful compression or decompression
+.
+.IP "\(bu" 4
+\fB\-k\fR, \fB\-\-keep\fR: keep source file(s) after successful compression or decompression\. This is the default behavior\.
+.
+.IP "\(bu" 4
+\fB\-r\fR: operate recursively on directories
+.
+.IP "\(bu" 4
+\fB\-\-filelist=FILE\fR read a list of files to process as content from \fBFILE\fR\. Format is compatible with \fBls\fR output, with one file per line\.
+.
+.IP "\(bu" 4
+\fB\-\-output\-dir\-flat[=dir]\fR: resulting files are stored into target \fBdir\fR directory, instead of same directory as origin file\. Be aware that this command can introduce name collision issues, if multiple files, from different directories, end up having the same name\. Collision resolution ensures first file with a given name will be present in \fBdir\fR, while in combination with \fB\-f\fR, the last file will be present instead\.
+.
+.IP "\(bu" 4
+\fB\-\-format=FORMAT\fR: compress and decompress in other formats\. If compiled with support, zstd can compress to or decompress from other compression algorithm formats\. Possibly available options are \fBzstd\fR, \fBgzip\fR, \fBxz\fR, \fBlzma\fR, and \fBlz4\fR\. If no such format is provided, \fBzstd\fR is the default\.
+.
+.IP "\(bu" 4
+\fB\-h\fR/\fB\-H\fR, \fB\-\-help\fR: display help/long help and exit
+.
+.IP "\(bu" 4
+\fB\-V\fR, \fB\-\-version\fR: display version number and exit\. Advanced : \fB\-vV\fR also displays supported formats\. \fB\-vvV\fR also displays POSIX support\.
+.
+.IP "\(bu" 4
+\fB\-v\fR, \fB\-\-verbose\fR: verbose mode
+.
+.IP "\(bu" 4
+\fB\-\-show\-default\-cparams\fR: Shows the default compresssion parameters that will be used for a particular src file\. If the provided src file is not a regular file (eg\. named pipe), the cli will just output the default paramters\. That is, the parameters that are used when the src size is unknown\.
+.
+.IP "\(bu" 4
+\fB\-q\fR, \fB\-\-quiet\fR: suppress warnings, interactivity, and notifications\. specify twice to suppress errors too\.
+.
+.IP "\(bu" 4
+\fB\-\-no\-progress\fR: do not display the progress bar, but keep all other messages\.
+.
+.IP "\(bu" 4
+\fB\-C\fR, \fB\-\-[no\-]check\fR: add integrity check computed from uncompressed data (default: enabled)
+.
+.IP "\(bu" 4
+\fB\-\-\fR: All arguments after \fB\-\-\fR are treated as files
+.
+.IP "" 0
+.
+.SS "Restricted usage of Environment Variables"
+Using environment variables to set parameters has security implications\. Therefore, this avenue is intentionally restricted\. Only \fBZSTD_CLEVEL\fR is supported currently, for setting compression level\. \fBZSTD_CLEVEL\fR can be used to set the level between 1 and 19 (the "normal" range)\. If the value of \fBZSTD_CLEVEL\fR is not a valid integer, it will be ignored with a warning message\. \fBZSTD_CLEVEL\fR just replaces the default compression level (\fB3\fR)\. It can be overridden by corresponding command line arguments\.
+.
+.SH "DICTIONARY BUILDER"
+\fBzstd\fR offers \fIdictionary\fR compression, which greatly improves efficiency on small files and messages\. It\'s possible to train \fBzstd\fR with a set of samples, the result of which is saved into a file called a \fBdictionary\fR\. Then during compression and decompression, reference the same dictionary, using command \fB\-D dictionaryFileName\fR\. Compression of small files similar to the sample set will be greatly improved\.
+.
+.TP
+\fB\-\-train FILEs\fR
+Use FILEs as training set to create a dictionary\. The training set should contain a lot of small files (> 100), and weight typically 100x the target dictionary size (for example, 10 MB for a 100 KB dictionary)\.
+.
+.IP
+Supports multithreading if \fBzstd\fR is compiled with threading support\. Additional parameters can be specified with \fB\-\-train\-fastcover\fR\. The legacy dictionary builder can be accessed with \fB\-\-train\-legacy\fR\. The cover dictionary builder can be accessed with \fB\-\-train\-cover\fR\. Equivalent to \fB\-\-train\-fastcover=d=8,steps=4\fR\.
+.
+.TP
+\fB\-o file\fR
+Dictionary saved into \fBfile\fR (default name: dictionary)\.
+.
+.TP
+\fB\-\-maxdict=#\fR
+Limit dictionary to specified size (default: 112640)\.
+.
+.TP
+\fB\-#\fR
+Use \fB#\fR compression level during training (optional)\. Will generate statistics more tuned for selected compression level, resulting in a \fIsmall\fR compression ratio improvement for this level\.
+.
+.TP
+\fB\-B#\fR
+Split input files in blocks of size # (default: no split)
+.
+.TP
+\fB\-\-dictID=#\fR
+A dictionary ID is a locally unique ID that a decoder can use to verify it is using the right dictionary\. By default, zstd will create a 4\-bytes random number ID\. It\'s possible to give a precise number instead\. Short numbers have an advantage : an ID < 256 will only need 1 byte in the compressed frame header, and an ID < 65536 will only need 2 bytes\. This compares favorably to 4 bytes default\. However, it\'s up to the dictionary manager to not assign twice the same ID to 2 different dictionaries\.
+.
+.TP
+\fB\-\-train\-cover[=k#,d=#,steps=#,split=#,shrink[=#]]\fR
+Select parameters for the default dictionary builder algorithm named cover\. If \fId\fR is not specified, then it tries \fId\fR = 6 and \fId\fR = 8\. If \fIk\fR is not specified, then it tries \fIsteps\fR values in the range [50, 2000]\. If \fIsteps\fR is not specified, then the default value of 40 is used\. If \fIsplit\fR is not specified or split <= 0, then the default value of 100 is used\. Requires that \fId\fR <= \fIk\fR\. If \fIshrink\fR flag is not used, then the default value for \fIshrinkDict\fR of 0 is used\. If \fIshrink\fR is not specified, then the default value for \fIshrinkDictMaxRegression\fR of 1 is used\.
+.
+.IP
+Selects segments of size \fIk\fR with highest score to put in the dictionary\. The score of a segment is computed by the sum of the frequencies of all the subsegments of size \fId\fR\. Generally \fId\fR should be in the range [6, 8], occasionally up to 16, but the algorithm will run faster with d <= \fI8\fR\. Good values for \fIk\fR vary widely based on the input data, but a safe range is [2 * \fId\fR, 2000]\. If \fIsplit\fR is 100, all input samples are used for both training and testing to find optimal \fId\fR and \fIk\fR to build dictionary\. Supports multithreading if \fBzstd\fR is compiled with threading support\. Having \fIshrink\fR enabled takes a truncated dictionary of minimum size and doubles in size until compression ratio of the truncated dictionary is at most \fIshrinkDictMaxRegression%\fR worse than the compression ratio of the largest dictionary\.
+.
+.IP
+Examples:
+.
+.IP
+\fBzstd \-\-train\-cover FILEs\fR
+.
+.IP
+\fBzstd \-\-train\-cover=k=50,d=8 FILEs\fR
+.
+.IP
+\fBzstd \-\-train\-cover=d=8,steps=500 FILEs\fR
+.
+.IP
+\fBzstd \-\-train\-cover=k=50 FILEs\fR
+.
+.IP
+\fBzstd \-\-train\-cover=k=50,split=60 FILEs\fR
+.
+.IP
+\fBzstd \-\-train\-cover=shrink FILEs\fR
+.
+.IP
+\fBzstd \-\-train\-cover=shrink=2 FILEs\fR
+.
+.TP
+\fB\-\-train\-fastcover[=k#,d=#,f=#,steps=#,split=#,accel=#]\fR
+Same as cover but with extra parameters \fIf\fR and \fIaccel\fR and different default value of split If \fIsplit\fR is not specified, then it tries \fIsplit\fR = 75\. If \fIf\fR is not specified, then it tries \fIf\fR = 20\. Requires that 0 < \fIf\fR < 32\. If \fIaccel\fR is not specified, then it tries \fIaccel\fR = 1\. Requires that 0 < \fIaccel\fR <= 10\. Requires that \fId\fR = 6 or \fId\fR = 8\.
+.
+.IP
+\fIf\fR is log of size of array that keeps track of frequency of subsegments of size \fId\fR\. The subsegment is hashed to an index in the range [0,2^\fIf\fR \- 1]\. It is possible that 2 different subsegments are hashed to the same index, and they are considered as the same subsegment when computing frequency\. Using a higher \fIf\fR reduces collision but takes longer\.
+.
+.IP
+Examples:
+.
+.IP
+\fBzstd \-\-train\-fastcover FILEs\fR
+.
+.IP
+\fBzstd \-\-train\-fastcover=d=8,f=15,accel=2 FILEs\fR
+.
+.TP
+\fB\-\-train\-legacy[=selectivity=#]\fR
+Use legacy dictionary builder algorithm with the given dictionary \fIselectivity\fR (default: 9)\. The smaller the \fIselectivity\fR value, the denser the dictionary, improving its efficiency but reducing its possible maximum size\. \fB\-\-train\-legacy=s=#\fR is also accepted\.
+.
+.IP
+Examples:
+.
+.IP
+\fBzstd \-\-train\-legacy FILEs\fR
+.
+.IP
+\fBzstd \-\-train\-legacy=selectivity=8 FILEs\fR
+.
+.SH "BENCHMARK"
+.
+.TP
+\fB\-b#\fR
+benchmark file(s) using compression level #
+.
+.TP
+\fB\-e#\fR
+benchmark file(s) using multiple compression levels, from \fB\-b#\fR to \fB\-e#\fR (inclusive)
+.
+.TP
+\fB\-i#\fR
+minimum evaluation time, in seconds (default: 3s), benchmark mode only
+.
+.TP
+\fB\-B#\fR, \fB\-\-block\-size=#\fR
+cut file(s) into independent blocks of size # (default: no block)
+.
+.TP
+\fB\-\-priority=rt\fR
+set process priority to real\-time
+.
+.P
+\fBOutput Format:\fR CompressionLevel#Filename : IntputSize \-> OutputSize (CompressionRatio), CompressionSpeed, DecompressionSpeed
+.
+.P
+\fBMethodology:\fR For both compression and decompression speed, the entire input is compressed/decompressed in\-memory to measure speed\. A run lasts at least 1 sec, so when files are small, they are compressed/decompressed several times per run, in order to improve measurement accuracy\.
+.
+.SH "ADVANCED COMPRESSION OPTIONS"
+.
+.SS "\-\-zstd[=options]:"
+\fBzstd\fR provides 22 predefined compression levels\. The selected or default predefined compression level can be changed with advanced compression options\. The \fIoptions\fR are provided as a comma\-separated list\. You may specify only the options you want to change and the rest will be taken from the selected or default compression level\. The list of available \fIoptions\fR:
+.
+.TP
+\fBstrategy\fR=\fIstrat\fR, \fBstrat\fR=\fIstrat\fR
+Specify a strategy used by a match finder\.
+.
+.IP
+There are 9 strategies numbered from 1 to 9, from faster to stronger: 1=ZSTD_fast, 2=ZSTD_dfast, 3=ZSTD_greedy, 4=ZSTD_lazy, 5=ZSTD_lazy2, 6=ZSTD_btlazy2, 7=ZSTD_btopt, 8=ZSTD_btultra, 9=ZSTD_btultra2\.
+.
+.TP
+\fBwindowLog\fR=\fIwlog\fR, \fBwlog\fR=\fIwlog\fR
+Specify the maximum number of bits for a match distance\.
+.
+.IP
+The higher number of increases the chance to find a match which usually improves compression ratio\. It also increases memory requirements for the compressor and decompressor\. The minimum \fIwlog\fR is 10 (1 KiB) and the maximum is 30 (1 GiB) on 32\-bit platforms and 31 (2 GiB) on 64\-bit platforms\.
+.
+.IP
+Note: If \fBwindowLog\fR is set to larger than 27, \fB\-\-long=windowLog\fR or \fB\-\-memory=windowSize\fR needs to be passed to the decompressor\.
+.
+.TP
+\fBhashLog\fR=\fIhlog\fR, \fBhlog\fR=\fIhlog\fR
+Specify the maximum number of bits for a hash table\.
+.
+.IP
+Bigger hash tables cause less collisions which usually makes compression faster, but requires more memory during compression\.
+.
+.IP
+The minimum \fIhlog\fR is 6 (64 B) and the maximum is 30 (1 GiB)\.
+.
+.TP
+\fBchainLog\fR=\fIclog\fR, \fBclog\fR=\fIclog\fR
+Specify the maximum number of bits for a hash chain or a binary tree\.
+.
+.IP
+Higher numbers of bits increases the chance to find a match which usually improves compression ratio\. It also slows down compression speed and increases memory requirements for compression\. This option is ignored for the ZSTD_fast strategy\.
+.
+.IP
+The minimum \fIclog\fR is 6 (64 B) and the maximum is 29 (524 Mib) on 32\-bit platforms and 30 (1 Gib) on 64\-bit platforms\.
+.
+.TP
+\fBsearchLog\fR=\fIslog\fR, \fBslog\fR=\fIslog\fR
+Specify the maximum number of searches in a hash chain or a binary tree using logarithmic scale\.
+.
+.IP
+More searches increases the chance to find a match which usually increases compression ratio but decreases compression speed\.
+.
+.IP
+The minimum \fIslog\fR is 1 and the maximum is \'windowLog\' \- 1\.
+.
+.TP
+\fBminMatch\fR=\fImml\fR, \fBmml\fR=\fImml\fR
+Specify the minimum searched length of a match in a hash table\.
+.
+.IP
+Larger search lengths usually decrease compression ratio but improve decompression speed\.
+.
+.IP
+The minimum \fImml\fR is 3 and the maximum is 7\.
+.
+.TP
+\fBtargetLength\fR=\fItlen\fR, \fBtlen\fR=\fItlen\fR
+The impact of this field vary depending on selected strategy\.
+.
+.IP
+For ZSTD_btopt, ZSTD_btultra and ZSTD_btultra2, it specifies the minimum match length that causes match finder to stop searching\. A larger \fBtargetLength\fR usually improves compression ratio but decreases compression speed\. t For ZSTD_fast, it triggers ultra\-fast mode when > 0\. The value represents the amount of data skipped between match sampling\. Impact is reversed : a larger \fBtargetLength\fR increases compression speed but decreases compression ratio\.
+.
+.IP
+For all other strategies, this field has no impact\.
+.
+.IP
+The minimum \fItlen\fR is 0 and the maximum is 128 Kib\.
+.
+.TP
+\fBoverlapLog\fR=\fIovlog\fR, \fBovlog\fR=\fIovlog\fR
+Determine \fBoverlapSize\fR, amount of data reloaded from previous job\. This parameter is only available when multithreading is enabled\. Reloading more data improves compression ratio, but decreases speed\.
+.
+.IP
+The minimum \fIovlog\fR is 0, and the maximum is 9\. 1 means "no overlap", hence completely independent jobs\. 9 means "full overlap", meaning up to \fBwindowSize\fR is reloaded from previous job\. Reducing \fIovlog\fR by 1 reduces the reloaded amount by a factor 2\. For example, 8 means "windowSize/2", and 6 means "windowSize/8"\. Value 0 is special and means "default" : \fIovlog\fR is automatically determined by \fBzstd\fR\. In which case, \fIovlog\fR will range from 6 to 9, depending on selected \fIstrat\fR\.
+.
+.TP
+\fBldmHashLog\fR=\fIlhlog\fR, \fBlhlog\fR=\fIlhlog\fR
+Specify the maximum size for a hash table used for long distance matching\.
+.
+.IP
+This option is ignored unless long distance matching is enabled\.
+.
+.IP
+Bigger hash tables usually improve compression ratio at the expense of more memory during compression and a decrease in compression speed\.
+.
+.IP
+The minimum \fIlhlog\fR is 6 and the maximum is 30 (default: 20)\.
+.
+.TP
+\fBldmMinMatch\fR=\fIlmml\fR, \fBlmml\fR=\fIlmml\fR
+Specify the minimum searched length of a match for long distance matching\.
+.
+.IP
+This option is ignored unless long distance matching is enabled\.
+.
+.IP
+Larger/very small values usually decrease compression ratio\.
+.
+.IP
+The minimum \fIlmml\fR is 4 and the maximum is 4096 (default: 64)\.
+.
+.TP
+\fBldmBucketSizeLog\fR=\fIlblog\fR, \fBlblog\fR=\fIlblog\fR
+Specify the size of each bucket for the hash table used for long distance matching\.
+.
+.IP
+This option is ignored unless long distance matching is enabled\.
+.
+.IP
+Larger bucket sizes improve collision resolution but decrease compression speed\.
+.
+.IP
+The minimum \fIlblog\fR is 1 and the maximum is 8 (default: 3)\.
+.
+.TP
+\fBldmHashRateLog\fR=\fIlhrlog\fR, \fBlhrlog\fR=\fIlhrlog\fR
+Specify the frequency of inserting entries into the long distance matching hash table\.
+.
+.IP
+This option is ignored unless long distance matching is enabled\.
+.
+.IP
+Larger values will improve compression speed\. Deviating far from the default value will likely result in a decrease in compression ratio\.
+.
+.IP
+The default value is \fBwlog \- lhlog\fR\.
+.
+.SS "Example"
+The following parameters sets advanced compression options to something similar to predefined level 19 for files bigger than 256 KB:
+.
+.P
+\fB\-\-zstd\fR=wlog=23,clog=23,hlog=22,slog=6,mml=3,tlen=48,strat=6
+.
+.SS "\-B#:"
+Select the size of each compression job\. This parameter is available only when multi\-threading is enabled\. Default value is \fB4 * windowSize\fR, which means it varies depending on compression level\. \fB\-B#\fR makes it possible to select a custom value\. Note that job size must respect a minimum value which is enforced transparently\. This minimum is either 1 MB, or \fBoverlapSize\fR, whichever is largest\.
+.
+.SH "BUGS"
+Report bugs at: https://github\.com/facebook/zstd/issues
+.
+.SH "AUTHOR"
+Yann Collet
diff --git a/src/zstd/programs/zstd.1.md b/src/zstd/programs/zstd.1.md
new file mode 100644
index 000000000..550e2e53f
--- /dev/null
+++ b/src/zstd/programs/zstd.1.md
@@ -0,0 +1,562 @@
+zstd(1) -- zstd, zstdmt, unzstd, zstdcat - Compress or decompress .zst files
+============================================================================
+
+SYNOPSIS
+--------
+
+`zstd` [*OPTIONS*] [-|_INPUT-FILE_] [-o _OUTPUT-FILE_]
+
+`zstdmt` is equivalent to `zstd -T0`
+
+`unzstd` is equivalent to `zstd -d`
+
+`zstdcat` is equivalent to `zstd -dcf`
+
+
+DESCRIPTION
+-----------
+`zstd` is a fast lossless compression algorithm and data compression tool,
+with command line syntax similar to `gzip (1)` and `xz (1)`.
+It is based on the **LZ77** family, with further FSE & huff0 entropy stages.
+`zstd` offers highly configurable compression speed,
+with fast modes at > 200 MB/s per core,
+and strong modes nearing lzma compression ratios.
+It also features a very fast decoder, with speeds > 500 MB/s per core.
+
+`zstd` command line syntax is generally similar to gzip,
+but features the following differences :
+
+  - Source files are preserved by default.
+    It's possible to remove them automatically by using the `--rm` command.
+  - When compressing a single file, `zstd` displays progress notifications
+    and result summary by default.
+    Use `-q` to turn them off.
+  - `zstd` does not accept input from console,
+    but it properly accepts `stdin` when it's not the console.
+  - `zstd` displays a short help page when command line is an error.
+    Use `-q` to turn it off.
+
+`zstd` compresses or decompresses each _file_ according to the selected
+operation mode.
+If no _files_ are given or _file_ is `-`, `zstd` reads from standard input
+and writes the processed data to standard output.
+`zstd` will refuse to write compressed data to standard output
+if it is a terminal : it will display an error message and skip the _file_.
+Similarly, `zstd` will refuse to read compressed data from standard input
+if it is a terminal.
+
+Unless `--stdout` or `-o` is specified, _files_ are written to a new file
+whose name is derived from the source _file_ name:
+
+* When compressing, the suffix `.zst` is appended to the source filename to
+  get the target filename.
+* When decompressing, the `.zst` suffix is removed from the source filename to
+  get the target filename
+
+### Concatenation with .zst files
+It is possible to concatenate `.zst` files as is.
+`zstd` will decompress such files as if they were a single `.zst` file.
+
+OPTIONS
+-------
+
+### Integer suffixes and special values
+In most places where an integer argument is expected,
+an optional suffix is supported to easily indicate large integers.
+There must be no space between the integer and the suffix.
+
+* `KiB`:
+    Multiply the integer by 1,024 (2\^10).
+    `Ki`, `K`, and `KB` are accepted as synonyms for `KiB`.
+* `MiB`:
+    Multiply the integer by 1,048,576 (2\^20).
+    `Mi`, `M`, and `MB` are accepted as synonyms for `MiB`.
+
+### Operation mode
+If multiple operation mode options are given,
+the last one takes effect.
+
+* `-z`, `--compress`:
+    Compress.
+    This is the default operation mode when no operation mode option is specified
+    and no other operation mode is implied from the command name
+    (for example, `unzstd` implies `--decompress`).
+* `-d`, `--decompress`, `--uncompress`:
+    Decompress.
+* `-t`, `--test`:
+    Test the integrity of compressed _files_.
+    This option is equivalent to `--decompress --stdout` except that the
+    decompressed data is discarded instead of being written to standard output.
+    No files are created or removed.
+* `-b#`:
+    Benchmark file(s) using compression level #
+* `--train FILEs`:
+    Use FILEs as a training set to create a dictionary.
+    The training set should contain a lot of small files (> 100).
+* `-l`, `--list`:
+    Display information related to a zstd compressed file, such as size, ratio, and checksum.
+    Some of these fields may not be available.
+    This command can be augmented with the `-v` modifier.
+
+### Operation modifiers
+
+* `-#`:
+    `#` compression level \[1-19] (default: 3)
+* `--fast[=#]`:
+    switch to ultra-fast compression levels.
+    If `=#` is not present, it defaults to `1`.
+    The higher the value, the faster the compression speed,
+    at the cost of some compression ratio.
+    This setting overwrites compression level if one was set previously.
+    Similarly, if a compression level is set after `--fast`, it overrides it.
+* `--ultra`:
+    unlocks high compression levels 20+ (maximum 22), using a lot more memory.
+    Note that decompression will also require more memory when using these levels.
+* `--long[=#]`:
+    enables long distance matching with `#` `windowLog`, if not `#` is not
+    present it defaults to `27`.
+    This increases the window size (`windowLog`) and memory usage for both the
+    compressor and decompressor.
+    This setting is designed to improve the compression ratio for files with
+    long matches at a large distance.
+
+    Note: If `windowLog` is set to larger than 27, `--long=windowLog` or
+    `--memory=windowSize` needs to be passed to the decompressor.
+* `--patch-from=FILE`:
+    Specify the file to be used as a reference point for zstd's diff engine.
+    This is effectively dictionary compression with some convenient parameter
+    selection, namely that windowSize > srcSize.
+
+    Note: cannot use both this and -D together
+    Note: `--long` mode will be automatically activated if chainLog < fileLog
+        (fileLog being the windowLog requried to cover the whole file). You 
+        can also manually force it.
+	Node: for all levels, you can use --patch-from in --single-thread mode
+		to improve compression ratio at the cost of speed
+    Note: for level 19, you can get increased compression ratio at the cost 
+        of speed by specifying `--zstd=targetLength=` to be something large 
+        (i.e 4096), and by setting a large `--zstd=chainLog=`
+* `-M#`, `--memory=#`:
+    Set a memory usage limit. By default, Zstandard uses 128 MB for decompression
+    as the maximum amount of memory the decompressor is allowed to use, but you can
+    override this manually if need be in either direction (ie. you can increase or
+    decrease it).
+
+    This is also used during compression when using with --patch-from=. In this case,
+    this parameter overrides that maximum size allowed for a dictionary. (128 MB).
+* `-T#`, `--threads=#`:
+    Compress using `#` working threads (default: 1).
+    If `#` is 0, attempt to detect and use the number of physical CPU cores.
+    In all cases, the nb of threads is capped to ZSTDMT_NBTHREADS_MAX==200.
+    This modifier does nothing if `zstd` is compiled without multithread support.
+* `--single-thread`:
+    Does not spawn a thread for compression, use a single thread for both I/O and compression.
+    In this mode, compression is serialized with I/O, which is slightly slower.
+    (This is different from `-T1`, which spawns 1 compression thread in parallel of I/O).
+    This mode is the only one available when multithread support is disabled.
+    Single-thread mode features lower memory usage.
+    Final compressed result is slightly different from `-T1`.
+* `--adapt[=min=#,max=#]` :
+    `zstd` will dynamically adapt compression level to perceived I/O conditions.
+    Compression level adaptation can be observed live by using command `-v`.
+    Adaptation can be constrained between supplied `min` and `max` levels.
+    The feature works when combined with multi-threading and `--long` mode.
+    It does not work with `--single-thread`.
+    It sets window size to 8 MB by default (can be changed manually, see `wlog`).
+    Due to the chaotic nature of dynamic adaptation, compressed result is not reproducible.
+    _note_ : at the time of this writing, `--adapt` can remain stuck at low speed
+    when combined with multiple worker threads (>=2).
+* `--stream-size=#` :
+    Sets the pledged source size of input coming from a stream. This value must be exact, as it
+    will be included in the produced frame header. Incorrect stream sizes will cause an error.
+    This information will be used to better optimize compression parameters, resulting in
+    better and potentially faster compression, especially for smaller source sizes.
+* `--size-hint=#`:
+    When handling input from a stream, `zstd` must guess how large the source size
+    will be when optimizing compression parameters. If the stream size is relatively
+    small, this guess may be a poor one, resulting in a higher compression ratio than
+    expected. This feature allows for controlling the guess when needed.
+    Exact guesses result in better compression ratios. Overestimates result in slightly
+    degraded compression ratios, while underestimates may result in significant degradation.
+* `--rsyncable` :
+    `zstd` will periodically synchronize the compression state to make the
+    compressed file more rsync-friendly. There is a negligible impact to
+    compression ratio, and the faster compression levels will see a small
+    compression speed hit.
+    This feature does not work with `--single-thread`. You probably don't want
+    to use it with long range mode, since it will decrease the effectiveness of
+    the synchronization points, but your milage may vary.
+* `-D file`:
+    use `file` as Dictionary to compress or decompress FILE(s)
+* `--no-dictID`:
+    do not store dictionary ID within frame header (dictionary compression).
+    The decoder will have to rely on implicit knowledge about which dictionary to use,
+    it won't be able to check if it's correct.
+* `-o file`:
+    save result into `file` (only possible with a single _INPUT-FILE_)
+* `-f`, `--force`:
+    overwrite output without prompting, and (de)compress symbolic links
+* `-c`, `--stdout`:
+    force write to standard output, even if it is the console
+* `--[no-]sparse`:
+    enable / disable sparse FS support,
+    to make files with many zeroes smaller on disk.
+    Creating sparse files may save disk space and speed up decompression by
+    reducing the amount of disk I/O.
+    default: enabled when output is into a file,
+    and disabled when output is stdout.
+    This setting overrides default and can force sparse mode over stdout.
+* `--[no-]content-size`:
+    enable / disable whether or not the original size of the file is placed in
+    the header of the compressed file. The default option is 
+    --content-size (meaning that the original size will be placed in the header).
+* `--rm`:
+    remove source file(s) after successful compression or decompression
+* `-k`, `--keep`:
+    keep source file(s) after successful compression or decompression.
+    This is the default behavior.
+* `-r`:
+    operate recursively on directories
+* `--filelist=FILE`
+    read a list of files to process as content from `FILE`.
+    Format is compatible with `ls` output, with one file per line.
+* `--output-dir-flat[=dir]`:
+    resulting files are stored into target `dir` directory,
+    instead of same directory as origin file.
+    Be aware that this command can introduce name collision issues,
+    if multiple files, from different directories, end up having the same name.
+    Collision resolution ensures first file with a given name will be present in `dir`,
+    while in combination with `-f`, the last file will be present instead.
+* `--format=FORMAT`:
+    compress and decompress in other formats. If compiled with
+    support, zstd can compress to or decompress from other compression algorithm
+    formats. Possibly available options are `zstd`, `gzip`, `xz`, `lzma`, and `lz4`.
+    If no such format is provided, `zstd` is the default.
+* `-h`/`-H`, `--help`:
+    display help/long help and exit
+* `-V`, `--version`:
+    display version number and exit.
+    Advanced : `-vV` also displays supported formats.
+    `-vvV` also displays POSIX support.
+* `-v`, `--verbose`:
+    verbose mode
+* `--show-default-cparams`:
+    Shows the default compresssion parameters that will be used for a
+    particular src file. If the provided src file is not a regular file
+    (eg. named pipe), the cli will just output the default paramters.
+    That is, the parameters that are used when the src size is
+    unknown.
+* `-q`, `--quiet`:
+    suppress warnings, interactivity, and notifications.
+    specify twice to suppress errors too.
+* `--no-progress`:
+    do not display the progress bar, but keep all other messages.
+* `-C`, `--[no-]check`:
+    add integrity check computed from uncompressed data (default: enabled)
+* `--`:
+    All arguments after `--` are treated as files
+
+### Restricted usage of Environment Variables
+
+Using environment variables to set parameters has security implications.
+Therefore, this avenue is intentionally restricted.
+Only `ZSTD_CLEVEL` is supported currently, for setting compression level.
+`ZSTD_CLEVEL` can be used to set the level between 1 and 19 (the "normal" range).
+If the value of `ZSTD_CLEVEL` is not a valid integer, it will be ignored with a warning message.
+`ZSTD_CLEVEL` just replaces the default compression level (`3`).
+It can be overridden by corresponding command line arguments.
+
+
+DICTIONARY BUILDER
+------------------
+`zstd` offers _dictionary_ compression,
+which greatly improves efficiency on small files and messages.
+It's possible to train `zstd` with a set of samples,
+the result of which is saved into a file called a `dictionary`.
+Then during compression and decompression, reference the same dictionary,
+using command `-D dictionaryFileName`.
+Compression of small files similar to the sample set will be greatly improved.
+
+* `--train FILEs`:
+    Use FILEs as training set to create a dictionary.
+    The training set should contain a lot of small files (> 100),
+    and weight typically 100x the target dictionary size
+    (for example, 10 MB for a 100 KB dictionary).
+
+    Supports multithreading if `zstd` is compiled with threading support.
+    Additional parameters can be specified with `--train-fastcover`.
+    The legacy dictionary builder can be accessed with `--train-legacy`.
+    The cover dictionary builder can be accessed with `--train-cover`.
+    Equivalent to `--train-fastcover=d=8,steps=4`.
+* `-o file`:
+    Dictionary saved into `file` (default name: dictionary).
+* `--maxdict=#`:
+    Limit dictionary to specified size (default: 112640).
+* `-#`:
+    Use `#` compression level during training (optional).
+    Will generate statistics more tuned for selected compression level,
+    resulting in a _small_ compression ratio improvement for this level.
+* `-B#`:
+    Split input files in blocks of size # (default: no split)
+* `--dictID=#`:
+    A dictionary ID is a locally unique ID that a decoder can use to verify it is
+    using the right dictionary.
+    By default, zstd will create a 4-bytes random number ID.
+    It's possible to give a precise number instead.
+    Short numbers have an advantage : an ID < 256 will only need 1 byte in the
+    compressed frame header, and an ID < 65536 will only need 2 bytes.
+    This compares favorably to 4 bytes default.
+    However, it's up to the dictionary manager to not assign twice the same ID to
+    2 different dictionaries.
+* `--train-cover[=k#,d=#,steps=#,split=#,shrink[=#]]`:
+    Select parameters for the default dictionary builder algorithm named cover.
+    If _d_ is not specified, then it tries _d_ = 6 and _d_ = 8.
+    If _k_ is not specified, then it tries _steps_ values in the range [50, 2000].
+    If _steps_ is not specified, then the default value of 40 is used.
+    If _split_ is not specified or split <= 0, then the default value of 100 is used.
+    Requires that _d_ <= _k_.
+    If _shrink_ flag is not used, then the default value for _shrinkDict_ of 0 is used.
+    If _shrink_ is not specified, then the default value for _shrinkDictMaxRegression_ of 1 is used.
+
+    Selects segments of size _k_ with highest score to put in the dictionary.
+    The score of a segment is computed by the sum of the frequencies of all the
+    subsegments of size _d_.
+    Generally _d_ should be in the range [6, 8], occasionally up to 16, but the
+    algorithm will run faster with d <= _8_.
+    Good values for _k_ vary widely based on the input data, but a safe range is
+    [2 * _d_, 2000].
+    If _split_ is 100, all input samples are used for both training and testing
+    to find optimal _d_ and _k_ to build dictionary.
+    Supports multithreading if `zstd` is compiled with threading support.
+    Having _shrink_ enabled takes a truncated dictionary of minimum size and doubles
+    in size until compression ratio of the truncated dictionary is at most
+    _shrinkDictMaxRegression%_ worse than the compression ratio of the largest dictionary.
+
+    Examples:
+
+    `zstd --train-cover FILEs`
+
+    `zstd --train-cover=k=50,d=8 FILEs`
+
+    `zstd --train-cover=d=8,steps=500 FILEs`
+
+    `zstd --train-cover=k=50 FILEs`
+
+    `zstd --train-cover=k=50,split=60 FILEs`
+
+    `zstd --train-cover=shrink FILEs`
+
+    `zstd --train-cover=shrink=2 FILEs`
+
+* `--train-fastcover[=k#,d=#,f=#,steps=#,split=#,accel=#]`:
+    Same as cover but with extra parameters _f_ and _accel_ and different default value of split
+    If _split_ is not specified, then it tries _split_ = 75.
+    If _f_ is not specified, then it tries _f_ = 20.
+    Requires that 0 < _f_ < 32.
+    If _accel_ is not specified, then it tries _accel_ = 1.
+    Requires that 0 < _accel_ <= 10.
+    Requires that _d_ = 6 or _d_ = 8.
+
+    _f_ is log of size of array that keeps track of frequency of subsegments of size _d_.
+    The subsegment is hashed to an index in the range [0,2^_f_ - 1].
+    It is possible that 2 different subsegments are hashed to the same index, and they are considered as the same subsegment when computing frequency.
+    Using a higher _f_ reduces collision but takes longer.
+
+    Examples:
+
+    `zstd --train-fastcover FILEs`
+
+    `zstd --train-fastcover=d=8,f=15,accel=2 FILEs`
+
+* `--train-legacy[=selectivity=#]`:
+    Use legacy dictionary builder algorithm with the given dictionary
+    _selectivity_ (default: 9).
+    The smaller the _selectivity_ value, the denser the dictionary,
+    improving its efficiency but reducing its possible maximum size.
+    `--train-legacy=s=#` is also accepted.
+
+    Examples:
+
+    `zstd --train-legacy FILEs`
+
+    `zstd --train-legacy=selectivity=8 FILEs`
+
+
+BENCHMARK
+---------
+
+* `-b#`:
+    benchmark file(s) using compression level #
+* `-e#`:
+    benchmark file(s) using multiple compression levels, from `-b#` to `-e#` (inclusive)
+* `-i#`:
+    minimum evaluation time, in seconds (default: 3s), benchmark mode only
+* `-B#`, `--block-size=#`:
+    cut file(s) into independent blocks of size # (default: no block)
+* `--priority=rt`:
+    set process priority to real-time
+
+**Output Format:** CompressionLevel#Filename : IntputSize -> OutputSize (CompressionRatio), CompressionSpeed, DecompressionSpeed
+
+**Methodology:** For both compression and decompression speed, the entire input is compressed/decompressed in-memory to measure speed. A run lasts at least 1 sec, so when files are small, they are compressed/decompressed several times per run, in order to improve measurement accuracy.
+
+ADVANCED COMPRESSION OPTIONS
+----------------------------
+### --zstd[=options]:
+`zstd` provides 22 predefined compression levels.
+The selected or default predefined compression level can be changed with
+advanced compression options.
+The _options_ are provided as a comma-separated list.
+You may specify only the options you want to change and the rest will be
+taken from the selected or default compression level.
+The list of available _options_:
+
+- `strategy`=_strat_, `strat`=_strat_:
+    Specify a strategy used by a match finder.
+
+    There are 9 strategies numbered from 1 to 9, from faster to stronger:
+    1=ZSTD\_fast, 2=ZSTD\_dfast, 3=ZSTD\_greedy,
+    4=ZSTD\_lazy, 5=ZSTD\_lazy2, 6=ZSTD\_btlazy2,
+    7=ZSTD\_btopt, 8=ZSTD\_btultra, 9=ZSTD\_btultra2.
+
+- `windowLog`=_wlog_, `wlog`=_wlog_:
+    Specify the maximum number of bits for a match distance.
+
+    The higher number of increases the chance to find a match which usually
+    improves compression ratio.
+    It also increases memory requirements for the compressor and decompressor.
+    The minimum _wlog_ is 10 (1 KiB) and the maximum is 30 (1 GiB) on 32-bit
+    platforms and 31 (2 GiB) on 64-bit platforms.
+
+    Note: If `windowLog` is set to larger than 27, `--long=windowLog` or
+    `--memory=windowSize` needs to be passed to the decompressor.
+
+- `hashLog`=_hlog_, `hlog`=_hlog_:
+    Specify the maximum number of bits for a hash table.
+
+    Bigger hash tables cause less collisions which usually makes compression
+    faster, but requires more memory during compression.
+
+    The minimum _hlog_ is 6 (64 B) and the maximum is 30 (1 GiB).
+
+- `chainLog`=_clog_, `clog`=_clog_:
+    Specify the maximum number of bits for a hash chain or a binary tree.
+
+    Higher numbers of bits increases the chance to find a match which usually
+    improves compression ratio.
+    It also slows down compression speed and increases memory requirements for
+    compression.
+    This option is ignored for the ZSTD_fast strategy.
+
+    The minimum _clog_ is 6 (64 B) and the maximum is 29 (524 Mib) on 32-bit platforms
+    and 30 (1 Gib) on 64-bit platforms.
+
+- `searchLog`=_slog_, `slog`=_slog_:
+    Specify the maximum number of searches in a hash chain or a binary tree
+    using logarithmic scale.
+
+    More searches increases the chance to find a match which usually increases
+    compression ratio but decreases compression speed.
+
+    The minimum _slog_ is 1 and the maximum is 'windowLog' - 1.
+
+- `minMatch`=_mml_, `mml`=_mml_:
+    Specify the minimum searched length of a match in a hash table.
+
+    Larger search lengths usually decrease compression ratio but improve
+    decompression speed.
+
+    The minimum _mml_ is 3 and the maximum is 7.
+
+- `targetLength`=_tlen_, `tlen`=_tlen_:
+    The impact of this field vary depending on selected strategy.
+
+    For ZSTD\_btopt, ZSTD\_btultra and ZSTD\_btultra2, it specifies
+    the minimum match length that causes match finder to stop searching.
+    A larger `targetLength` usually improves compression ratio
+    but decreases compression speed.
+t
+    For ZSTD\_fast, it triggers ultra-fast mode when > 0.
+    The value represents the amount of data skipped between match sampling.
+    Impact is reversed : a larger `targetLength` increases compression speed
+    but decreases compression ratio.
+
+    For all other strategies, this field has no impact.
+
+    The minimum _tlen_ is 0 and the maximum is 128 Kib.
+
+- `overlapLog`=_ovlog_,  `ovlog`=_ovlog_:
+    Determine `overlapSize`, amount of data reloaded from previous job.
+    This parameter is only available when multithreading is enabled.
+    Reloading more data improves compression ratio, but decreases speed.
+
+    The minimum _ovlog_ is 0, and the maximum is 9.
+    1 means "no overlap", hence completely independent jobs.
+    9 means "full overlap", meaning up to `windowSize` is reloaded from previous job.
+    Reducing _ovlog_ by 1 reduces the reloaded amount by a factor 2.
+    For example, 8 means "windowSize/2", and 6 means "windowSize/8".
+    Value 0 is special and means "default" : _ovlog_ is automatically determined by `zstd`.
+    In which case, _ovlog_ will range from 6 to 9, depending on selected _strat_.
+
+- `ldmHashLog`=_lhlog_, `lhlog`=_lhlog_:
+    Specify the maximum size for a hash table used for long distance matching.
+
+    This option is ignored unless long distance matching is enabled.
+
+    Bigger hash tables usually improve compression ratio at the expense of more
+    memory during compression and a decrease in compression speed.
+
+    The minimum _lhlog_ is 6 and the maximum is 30 (default: 20).
+
+- `ldmMinMatch`=_lmml_, `lmml`=_lmml_:
+    Specify the minimum searched length of a match for long distance matching.
+
+    This option is ignored unless long distance matching is enabled.
+
+    Larger/very small values usually decrease compression ratio.
+
+    The minimum _lmml_ is 4 and the maximum is 4096 (default: 64).
+
+- `ldmBucketSizeLog`=_lblog_, `lblog`=_lblog_:
+    Specify the size of each bucket for the hash table used for long distance
+    matching.
+
+    This option is ignored unless long distance matching is enabled.
+
+    Larger bucket sizes improve collision resolution but decrease compression
+    speed.
+
+    The minimum _lblog_ is 1 and the maximum is 8 (default: 3).
+
+- `ldmHashRateLog`=_lhrlog_, `lhrlog`=_lhrlog_:
+    Specify the frequency of inserting entries into the long distance matching
+    hash table.
+
+    This option is ignored unless long distance matching is enabled.
+
+    Larger values will improve compression speed. Deviating far from the
+    default value will likely result in a decrease in compression ratio.
+
+    The default value is `wlog - lhlog`.
+
+### Example
+The following parameters sets advanced compression options to something
+similar to predefined level 19 for files bigger than 256 KB:
+
+`--zstd`=wlog=23,clog=23,hlog=22,slog=6,mml=3,tlen=48,strat=6
+
+### -B#:
+Select the size of each compression job.
+This parameter is available only when multi-threading is enabled.
+Default value is `4 * windowSize`, which means it varies depending on compression level.
+`-B#` makes it possible to select a custom value.
+Note that job size must respect a minimum value which is enforced transparently.
+This minimum is either 1 MB, or `overlapSize`, whichever is largest.
+
+BUGS
+----
+Report bugs at: https://github.com/facebook/zstd/issues
+
+AUTHOR
+------
+Yann Collet
diff --git a/src/zstd/programs/zstdcli.c b/src/zstd/programs/zstdcli.c
new file mode 100644
index 000000000..70e2b7066
--- /dev/null
+++ b/src/zstd/programs/zstdcli.c
@@ -0,0 +1,1352 @@
+/*
+ * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
+ */
+
+
+/*-************************************
+*  Tuning parameters
+**************************************/
+#ifndef ZSTDCLI_CLEVEL_DEFAULT
+#  define ZSTDCLI_CLEVEL_DEFAULT 3
+#endif
+
+#ifndef ZSTDCLI_CLEVEL_MAX
+#  define ZSTDCLI_CLEVEL_MAX 19   /* without using --ultra */
+#endif
+
+
+
+/*-************************************
+*  Dependencies
+**************************************/
+#include "platform.h" /* IS_CONSOLE, PLATFORM_POSIX_VERSION */
+#include "util.h"     /* UTIL_HAS_CREATEFILELIST, UTIL_createFileList */
+#include <stdlib.h>   /* getenv */
+#include <string.h>   /* strcmp, strlen */
+#include <stdio.h>    /* fprintf(), stdin, stdout, stderr */
+#include <errno.h>    /* errno */
+#include <assert.h>   /* assert */
+
+#include "fileio.h"   /* stdinmark, stdoutmark, ZSTD_EXTENSION */
+#ifndef ZSTD_NOBENCH
+#  include "benchzstd.h"  /* BMK_benchFiles */
+#endif
+#ifndef ZSTD_NODICT
+#  include "dibio.h"  /* ZDICT_cover_params_t, DiB_trainFromFiles() */
+#endif
+#include "../lib/zstd.h"  /* ZSTD_VERSION_STRING, ZSTD_minCLevel, ZSTD_maxCLevel */
+
+
+/*-************************************
+*  Constants
+**************************************/
+#define COMPRESSOR_NAME "zstd command line interface"
+#ifndef ZSTD_VERSION
+#  define ZSTD_VERSION "v" ZSTD_VERSION_STRING
+#endif
+#define AUTHOR "Yann Collet"
+#define WELCOME_MESSAGE "*** %s %i-bits %s, by %s ***\n", COMPRESSOR_NAME, (int)(sizeof(size_t)*8), ZSTD_VERSION, AUTHOR
+
+#define ZSTD_ZSTDMT "zstdmt"
+#define ZSTD_UNZSTD "unzstd"
+#define ZSTD_CAT "zstdcat"
+#define ZSTD_ZCAT "zcat"
+#define ZSTD_GZ "gzip"
+#define ZSTD_GUNZIP "gunzip"
+#define ZSTD_GZCAT "gzcat"
+#define ZSTD_LZMA "lzma"
+#define ZSTD_UNLZMA "unlzma"
+#define ZSTD_XZ "xz"
+#define ZSTD_UNXZ "unxz"
+#define ZSTD_LZ4 "lz4"
+#define ZSTD_UNLZ4 "unlz4"
+
+#define KB *(1 <<10)
+#define MB *(1 <<20)
+#define GB *(1U<<30)
+
+#define DISPLAY_LEVEL_DEFAULT 2
+
+static const char*    g_defaultDictName = "dictionary";
+static const unsigned g_defaultMaxDictSize = 110 KB;
+static const int      g_defaultDictCLevel = 3;
+static const unsigned g_defaultSelectivityLevel = 9;
+static const unsigned g_defaultMaxWindowLog = 27;
+#define OVERLAP_LOG_DEFAULT 9999
+#define LDM_PARAM_DEFAULT 9999  /* Default for parameters where 0 is valid */
+static U32 g_overlapLog = OVERLAP_LOG_DEFAULT;
+static U32 g_ldmHashLog = 0;
+static U32 g_ldmMinMatch = 0;
+static U32 g_ldmHashRateLog = LDM_PARAM_DEFAULT;
+static U32 g_ldmBucketSizeLog = LDM_PARAM_DEFAULT;
+
+
+#define DEFAULT_ACCEL 1
+
+typedef enum { cover, fastCover, legacy } dictType;
+
+/*-************************************
+*  Display Macros
+**************************************/
+#define DISPLAY_F(f, ...)    fprintf((f), __VA_ARGS__)
+#define DISPLAYOUT(...)      DISPLAY_F(stdout, __VA_ARGS__)
+#define DISPLAY(...)         DISPLAY_F(stderr, __VA_ARGS__)
+#define DISPLAYLEVEL(l, ...) { if (g_displayLevel>=l) { DISPLAY(__VA_ARGS__); } }
+static int g_displayLevel = DISPLAY_LEVEL_DEFAULT;   /* 0 : no display,  1: errors,  2 : + result + interaction + warnings,  3 : + progression,  4 : + information */
+
+
+/*-************************************
+*  Command Line
+**************************************/
+/* print help either in `stderr` or `stdout` depending on originating request
+ * error (badusage) => stderr
+ * help (usage_advanced) => stdout
+ */
+static void usage(FILE* f, const char* programName)
+{
+    DISPLAY_F(f, "Usage : \n");
+    DISPLAY_F(f, "      %s [args] [FILE(s)] [-o file] \n", programName);
+    DISPLAY_F(f, "\n");
+    DISPLAY_F(f, "FILE    : a filename \n");
+    DISPLAY_F(f, "          with no FILE, or when FILE is - , read standard input\n");
+    DISPLAY_F(f, "Arguments : \n");
+#ifndef ZSTD_NOCOMPRESS
+    DISPLAY_F(f, " -#     : # compression level (1-%d, default: %d) \n", ZSTDCLI_CLEVEL_MAX, ZSTDCLI_CLEVEL_DEFAULT);
+#endif
+#ifndef ZSTD_NODECOMPRESS
+    DISPLAY_F(f, " -d     : decompression \n");
+#endif
+    DISPLAY_F(f, " -D DICT: use DICT as Dictionary for compression or decompression \n");
+    DISPLAY_F(f, " -o file: result stored into `file` (only 1 output file) \n");
+    DISPLAY_F(f, " -f     : overwrite output without prompting, also (de)compress links \n");
+    DISPLAY_F(f, "--rm    : remove source file(s) after successful de/compression \n");
+    DISPLAY_F(f, " -k     : preserve source file(s) (default) \n");
+    DISPLAY_F(f, " -h/-H  : display help/long help and exit \n");
+}
+
+static void usage_advanced(const char* programName)
+{
+    DISPLAYOUT(WELCOME_MESSAGE);
+    usage(stdout, programName);
+    DISPLAYOUT( "\n");
+    DISPLAYOUT( "Advanced arguments : \n");
+    DISPLAYOUT( " -V     : display Version number and exit \n");
+
+    DISPLAYOUT( " -c     : force write to standard output, even if it is the console \n");
+
+    DISPLAYOUT( " -v     : verbose mode; specify multiple times to increase verbosity \n");
+    DISPLAYOUT( " -q     : suppress warnings; specify twice to suppress errors too \n");
+    DISPLAYOUT( "--no-progress : do not display the progress counter \n");
+
+#ifdef UTIL_HAS_CREATEFILELIST
+    DISPLAYOUT( " -r     : operate recursively on directories \n");
+    DISPLAYOUT( "--filelist=FILE : read list of files to operate upon from FILE \n");
+    DISPLAYOUT( "--output-dir-flat=DIR : all resulting files are stored into DIR \n");
+#endif
+
+    DISPLAYOUT( "--      : All arguments after \"--\" are treated as files \n");
+
+#ifndef ZSTD_NOCOMPRESS
+    DISPLAYOUT( "\n");
+    DISPLAYOUT( "Advanced compression arguments : \n");
+    DISPLAYOUT( "--ultra : enable levels beyond %i, up to %i (requires more memory) \n", ZSTDCLI_CLEVEL_MAX, ZSTD_maxCLevel());
+    DISPLAYOUT( "--long[=#]: enable long distance matching with given window log (default: %u) \n", g_defaultMaxWindowLog);
+    DISPLAYOUT( "--fast[=#]: switch to very fast compression levels (default: %u) \n", 1);
+    DISPLAYOUT( "--adapt : dynamically adapt compression level to I/O conditions \n");
+# ifdef ZSTD_MULTITHREAD
+    DISPLAYOUT( " -T#    : spawns # compression threads (default: 1, 0==# cores) \n");
+    DISPLAYOUT( " -B#    : select size of each job (default: 0==automatic) \n");
+    DISPLAYOUT( "--single-thread : use a single thread for both I/O and compression (result slightly different than -T1) \n");
+    DISPLAYOUT( "--rsyncable : compress using a rsync-friendly method (-B sets block size) \n");
+# endif
+    DISPLAYOUT( "--exclude-compressed: only compress files that are not already compressed \n");
+    DISPLAYOUT( "--stream-size=# : specify size of streaming input from `stdin` \n");
+    DISPLAYOUT( "--size-hint=# optimize compression parameters for streaming input of approximately this size \n");
+    DISPLAYOUT( "--target-compressed-block-size=# : generate compressed block of approximately targeted size \n");
+    DISPLAYOUT( "--no-dictID : don't write dictID into header (dictionary compression only) \n");
+    DISPLAYOUT( "--[no-]check : add XXH64 integrity checksum to frame (default: enabled) \n");
+    DISPLAYOUT( "--[no-]compress-literals : force (un)compressed literals \n");
+
+    DISPLAYOUT( "--format=zstd : compress files to the .zst format (default) \n");
+#ifdef ZSTD_GZCOMPRESS
+    DISPLAYOUT( "--format=gzip : compress files to the .gz format \n");
+#endif
+#ifdef ZSTD_LZMACOMPRESS
+    DISPLAYOUT( "--format=xz : compress files to the .xz format \n");
+    DISPLAYOUT( "--format=lzma : compress files to the .lzma format \n");
+#endif
+#ifdef ZSTD_LZ4COMPRESS
+    DISPLAYOUT( "--format=lz4 : compress files to the .lz4 format \n");
+#endif
+#endif  /* !ZSTD_NOCOMPRESS */
+
+#ifndef ZSTD_NODECOMPRESS
+    DISPLAYOUT( "\n");
+    DISPLAYOUT( "Advanced decompression arguments : \n");
+    DISPLAYOUT( " -l     : print information about zstd compressed files \n");
+    DISPLAYOUT( "--test  : test compressed file integrity \n");
+    DISPLAYOUT( " -M#    : Set a memory usage limit for decompression \n");
+# if ZSTD_SPARSE_DEFAULT
+    DISPLAYOUT( "--[no-]sparse : sparse mode (default: enabled on file, disabled on stdout) \n");
+# else
+    DISPLAYOUT( "--[no-]sparse : sparse mode (default: disabled) \n");
+# endif
+#endif  /* ZSTD_NODECOMPRESS */
+
+#ifndef ZSTD_NODICT
+    DISPLAYOUT( "\n");
+    DISPLAYOUT( "Dictionary builder : \n");
+    DISPLAYOUT( "--train ## : create a dictionary from a training set of files \n");
+    DISPLAYOUT( "--train-cover[=k=#,d=#,steps=#,split=#,shrink[=#]] : use the cover algorithm with optional args \n");
+    DISPLAYOUT( "--train-fastcover[=k=#,d=#,f=#,steps=#,split=#,accel=#,shrink[=#]] : use the fast cover algorithm with optional args \n");
+    DISPLAYOUT( "--train-legacy[=s=#] : use the legacy algorithm with selectivity (default: %u) \n", g_defaultSelectivityLevel);
+    DISPLAYOUT( " -o DICT : DICT is dictionary name (default: %s) \n", g_defaultDictName);
+    DISPLAYOUT( "--maxdict=# : limit dictionary to specified size (default: %u) \n", g_defaultMaxDictSize);
+    DISPLAYOUT( "--dictID=# : force dictionary ID to specified value (default: random) \n");
+#endif
+
+#ifndef ZSTD_NOBENCH
+    DISPLAYOUT( "\n");
+    DISPLAYOUT( "Benchmark arguments : \n");
+    DISPLAYOUT( " -b#    : benchmark file(s), using # compression level (default: %d) \n", ZSTDCLI_CLEVEL_DEFAULT);
+    DISPLAYOUT( " -e#    : test all compression levels successively from -b# to -e# (default: 1) \n");
+    DISPLAYOUT( " -i#    : minimum evaluation time in seconds (default: 3s) \n");
+    DISPLAYOUT( " -B#    : cut file into independent blocks of size # (default: no block) \n");
+    DISPLAYOUT( " -S     : output one benchmark result per input file (default: consolidated result) \n");
+    DISPLAYOUT( "--priority=rt : set process priority to real-time \n");
+#endif
+
+}
+
+static void badusage(const char* programName)
+{
+    DISPLAYLEVEL(1, "Incorrect parameters \n");
+    if (g_displayLevel >= 2) usage(stderr, programName);
+}
+
+static void waitEnter(void)
+{
+    int unused;
+    DISPLAY("Press enter to continue... \n");
+    unused = getchar();
+    (void)unused;
+}
+
+static const char* lastNameFromPath(const char* path)
+{
+    const char* name = path;
+    if (strrchr(name, '/')) name = strrchr(name, '/') + 1;
+    if (strrchr(name, '\\')) name = strrchr(name, '\\') + 1; /* windows */
+    return name;
+}
+
+/*! exeNameMatch() :
+    @return : a non-zero value if exeName matches test, excluding the extension
+   */
+static int exeNameMatch(const char* exeName, const char* test)
+{
+    return !strncmp(exeName, test, strlen(test)) &&
+        (exeName[strlen(test)] == '\0' || exeName[strlen(test)] == '.');
+}
+
+static void errorOut(const char* msg)
+{
+    DISPLAY("%s \n", msg); exit(1);
+}
+
+/*! readU32FromCharChecked() :
+ * @return 0 if success, and store the result in *value.
+ *  allows and interprets K, KB, KiB, M, MB and MiB suffix.
+ *  Will also modify `*stringPtr`, advancing it to position where it stopped reading.
+ * @return 1 if an overflow error occurs */
+static int readU32FromCharChecked(const char** stringPtr, unsigned* value)
+{
+    unsigned result = 0;
+    while ((**stringPtr >='0') && (**stringPtr <='9')) {
+        unsigned const max = ((unsigned)(-1)) / 10;
+        unsigned last = result;
+        if (result > max) return 1; /* overflow error */
+        result *= 10;
+        result += (unsigned)(**stringPtr - '0');
+        if (result < last) return 1; /* overflow error */
+        (*stringPtr)++ ;
+    }
+    if ((**stringPtr=='K') || (**stringPtr=='M')) {
+        unsigned const maxK = ((unsigned)(-1)) >> 10;
+        if (result > maxK) return 1; /* overflow error */
+        result <<= 10;
+        if (**stringPtr=='M') {
+            if (result > maxK) return 1; /* overflow error */
+            result <<= 10;
+        }
+        (*stringPtr)++;  /* skip `K` or `M` */
+        if (**stringPtr=='i') (*stringPtr)++;
+        if (**stringPtr=='B') (*stringPtr)++;
+    }
+    *value = result;
+    return 0;
+}
+
+/*! readU32FromChar() :
+ * @return : unsigned integer value read from input in `char` format.
+ *  allows and interprets K, KB, KiB, M, MB and MiB suffix.
+ *  Will also modify `*stringPtr`, advancing it to position where it stopped reading.
+ *  Note : function will exit() program if digit sequence overflows */
+static unsigned readU32FromChar(const char** stringPtr) {
+    static const char errorMsg[] = "error: numeric value overflows 32-bit unsigned int";
+    unsigned result;
+    if (readU32FromCharChecked(stringPtr, &result)) { errorOut(errorMsg); }
+    return result;
+}
+
+/*! readSizeTFromCharChecked() :
+ * @return 0 if success, and store the result in *value.
+ *  allows and interprets K, KB, KiB, M, MB and MiB suffix.
+ *  Will also modify `*stringPtr`, advancing it to position where it stopped reading.
+ * @return 1 if an overflow error occurs */
+static int readSizeTFromCharChecked(const char** stringPtr, size_t* value)
+{
+    size_t result = 0;
+    while ((**stringPtr >='0') && (**stringPtr <='9')) {
+        size_t const max = ((size_t)(-1)) / 10;
+        size_t last = result;
+        if (result > max) return 1; /* overflow error */
+        result *= 10;
+        result += (size_t)(**stringPtr - '0');
+        if (result < last) return 1; /* overflow error */
+        (*stringPtr)++ ;
+    }
+    if ((**stringPtr=='K') || (**stringPtr=='M')) {
+        size_t const maxK = ((size_t)(-1)) >> 10;
+        if (result > maxK) return 1; /* overflow error */
+        result <<= 10;
+        if (**stringPtr=='M') {
+            if (result > maxK) return 1; /* overflow error */
+            result <<= 10;
+        }
+        (*stringPtr)++;  /* skip `K` or `M` */
+        if (**stringPtr=='i') (*stringPtr)++;
+        if (**stringPtr=='B') (*stringPtr)++;
+    }
+    *value = result;
+    return 0;
+}
+
+/*! readSizeTFromChar() :
+ * @return : size_t value read from input in `char` format.
+ *  allows and interprets K, KB, KiB, M, MB and MiB suffix.
+ *  Will also modify `*stringPtr`, advancing it to position where it stopped reading.
+ *  Note : function will exit() program if digit sequence overflows */
+static size_t readSizeTFromChar(const char** stringPtr) {
+    static const char errorMsg[] = "error: numeric value overflows size_t";
+    size_t result;
+    if (readSizeTFromCharChecked(stringPtr, &result)) { errorOut(errorMsg); }
+    return result;
+}
+
+/** longCommandWArg() :
+ *  check if *stringPtr is the same as longCommand.
+ *  If yes, @return 1 and advances *stringPtr to the position which immediately follows longCommand.
+ * @return 0 and doesn't modify *stringPtr otherwise.
+ */
+static int longCommandWArg(const char** stringPtr, const char* longCommand)
+{
+    size_t const comSize = strlen(longCommand);
+    int const result = !strncmp(*stringPtr, longCommand, comSize);
+    if (result) *stringPtr += comSize;
+    return result;
+}
+
+
+#ifndef ZSTD_NODICT
+
+static const unsigned kDefaultRegression = 1;
+/**
+ * parseCoverParameters() :
+ * reads cover parameters from *stringPtr (e.g. "--train-cover=k=48,d=8,steps=32") into *params
+ * @return 1 means that cover parameters were correct
+ * @return 0 in case of malformed parameters
+ */
+static unsigned parseCoverParameters(const char* stringPtr, ZDICT_cover_params_t* params)
+{
+    memset(params, 0, sizeof(*params));
+    for (; ;) {
+        if (longCommandWArg(&stringPtr, "k=")) { params->k = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "d=")) { params->d = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "steps=")) { params->steps = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "split=")) {
+          unsigned splitPercentage = readU32FromChar(&stringPtr);
+          params->splitPoint = (double)splitPercentage / 100.0;
+          if (stringPtr[0]==',') { stringPtr++; continue; } else break;
+        }
+        if (longCommandWArg(&stringPtr, "shrink")) {
+          params->shrinkDictMaxRegression = kDefaultRegression;
+          params->shrinkDict = 1;
+          if (stringPtr[0]=='=') {
+            stringPtr++;
+            params->shrinkDictMaxRegression = readU32FromChar(&stringPtr);
+          }
+          if (stringPtr[0]==',') {
+            stringPtr++;
+            continue;
+          }
+          else break;
+        }
+        return 0;
+    }
+    if (stringPtr[0] != 0) return 0;
+    DISPLAYLEVEL(4, "cover: k=%u\nd=%u\nsteps=%u\nsplit=%u\nshrink%u\n", params->k, params->d, params->steps, (unsigned)(params->splitPoint * 100), params->shrinkDictMaxRegression);
+    return 1;
+}
+
+/**
+ * parseFastCoverParameters() :
+ * reads fastcover parameters from *stringPtr (e.g. "--train-fastcover=k=48,d=8,f=20,steps=32,accel=2") into *params
+ * @return 1 means that fastcover parameters were correct
+ * @return 0 in case of malformed parameters
+ */
+static unsigned parseFastCoverParameters(const char* stringPtr, ZDICT_fastCover_params_t* params)
+{
+    memset(params, 0, sizeof(*params));
+    for (; ;) {
+        if (longCommandWArg(&stringPtr, "k=")) { params->k = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "d=")) { params->d = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "f=")) { params->f = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "steps=")) { params->steps = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "accel=")) { params->accel = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "split=")) {
+          unsigned splitPercentage = readU32FromChar(&stringPtr);
+          params->splitPoint = (double)splitPercentage / 100.0;
+          if (stringPtr[0]==',') { stringPtr++; continue; } else break;
+        }
+        if (longCommandWArg(&stringPtr, "shrink")) {
+          params->shrinkDictMaxRegression = kDefaultRegression;
+          params->shrinkDict = 1;
+          if (stringPtr[0]=='=') {
+            stringPtr++;
+            params->shrinkDictMaxRegression = readU32FromChar(&stringPtr);
+          }
+          if (stringPtr[0]==',') {
+            stringPtr++;
+            continue;
+          }
+          else break;
+        }
+        return 0;
+    }
+    if (stringPtr[0] != 0) return 0;
+    DISPLAYLEVEL(4, "cover: k=%u\nd=%u\nf=%u\nsteps=%u\nsplit=%u\naccel=%u\nshrink=%u\n", params->k, params->d, params->f, params->steps, (unsigned)(params->splitPoint * 100), params->accel, params->shrinkDictMaxRegression);
+    return 1;
+}
+
+/**
+ * parseLegacyParameters() :
+ * reads legacy dictionary builder parameters from *stringPtr (e.g. "--train-legacy=selectivity=8") into *selectivity
+ * @return 1 means that legacy dictionary builder parameters were correct
+ * @return 0 in case of malformed parameters
+ */
+static unsigned parseLegacyParameters(const char* stringPtr, unsigned* selectivity)
+{
+    if (!longCommandWArg(&stringPtr, "s=") && !longCommandWArg(&stringPtr, "selectivity=")) { return 0; }
+    *selectivity = readU32FromChar(&stringPtr);
+    if (stringPtr[0] != 0) return 0;
+    DISPLAYLEVEL(4, "legacy: selectivity=%u\n", *selectivity);
+    return 1;
+}
+
+static ZDICT_cover_params_t defaultCoverParams(void)
+{
+    ZDICT_cover_params_t params;
+    memset(&params, 0, sizeof(params));
+    params.d = 8;
+    params.steps = 4;
+    params.splitPoint = 1.0;
+    params.shrinkDict = 0;
+    params.shrinkDictMaxRegression = kDefaultRegression;
+    return params;
+}
+
+static ZDICT_fastCover_params_t defaultFastCoverParams(void)
+{
+    ZDICT_fastCover_params_t params;
+    memset(&params, 0, sizeof(params));
+    params.d = 8;
+    params.f = 20;
+    params.steps = 4;
+    params.splitPoint = 0.75; /* different from default splitPoint of cover */
+    params.accel = DEFAULT_ACCEL;
+    params.shrinkDict = 0;
+    params.shrinkDictMaxRegression = kDefaultRegression;
+    return params;
+}
+#endif
+
+
+/** parseAdaptParameters() :
+ *  reads adapt parameters from *stringPtr (e.g. "--zstd=min=1,max=19) and store them into adaptMinPtr and adaptMaxPtr.
+ *  Both adaptMinPtr and adaptMaxPtr must be already allocated and correctly initialized.
+ *  There is no guarantee that any of these values will be updated.
+ *  @return 1 means that parsing was successful,
+ *  @return 0 in case of malformed parameters
+ */
+static unsigned parseAdaptParameters(const char* stringPtr, int* adaptMinPtr, int* adaptMaxPtr)
+{
+    for ( ; ;) {
+        if (longCommandWArg(&stringPtr, "min=")) { *adaptMinPtr = (int)readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "max=")) { *adaptMaxPtr = (int)readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        DISPLAYLEVEL(4, "invalid compression parameter \n");
+        return 0;
+    }
+    if (stringPtr[0] != 0) return 0; /* check the end of string */
+    if (*adaptMinPtr > *adaptMaxPtr) {
+        DISPLAYLEVEL(4, "incoherent adaptation limits \n");
+        return 0;
+    }
+    return 1;
+}
+
+
+/** parseCompressionParameters() :
+ *  reads compression parameters from *stringPtr (e.g. "--zstd=wlog=23,clog=23,hlog=22,slog=6,mml=3,tlen=48,strat=6") into *params
+ *  @return 1 means that compression parameters were correct
+ *  @return 0 in case of malformed parameters
+ */
+static unsigned parseCompressionParameters(const char* stringPtr, ZSTD_compressionParameters* params)
+{
+    for ( ; ;) {
+        if (longCommandWArg(&stringPtr, "windowLog=") || longCommandWArg(&stringPtr, "wlog=")) { params->windowLog = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "chainLog=") || longCommandWArg(&stringPtr, "clog=")) { params->chainLog = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "hashLog=") || longCommandWArg(&stringPtr, "hlog=")) { params->hashLog = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "searchLog=") || longCommandWArg(&stringPtr, "slog=")) { params->searchLog = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "minMatch=") || longCommandWArg(&stringPtr, "mml=")) { params->minMatch = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "targetLength=") || longCommandWArg(&stringPtr, "tlen=")) { params->targetLength = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "strategy=") || longCommandWArg(&stringPtr, "strat=")) { params->strategy = (ZSTD_strategy)(readU32FromChar(&stringPtr)); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "overlapLog=") || longCommandWArg(&stringPtr, "ovlog=")) { g_overlapLog = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "ldmHashLog=") || longCommandWArg(&stringPtr, "lhlog=")) { g_ldmHashLog = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "ldmMinMatch=") || longCommandWArg(&stringPtr, "lmml=")) { g_ldmMinMatch = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "ldmBucketSizeLog=") || longCommandWArg(&stringPtr, "lblog=")) { g_ldmBucketSizeLog = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        if (longCommandWArg(&stringPtr, "ldmHashRateLog=") || longCommandWArg(&stringPtr, "lhrlog=")) { g_ldmHashRateLog = readU32FromChar(&stringPtr); if (stringPtr[0]==',') { stringPtr++; continue; } else break; }
+        DISPLAYLEVEL(4, "invalid compression parameter \n");
+        return 0;
+    }
+
+    DISPLAYLEVEL(4, "windowLog=%d, chainLog=%d, hashLog=%d, searchLog=%d \n", params->windowLog, params->chainLog, params->hashLog, params->searchLog);
+    DISPLAYLEVEL(4, "minMatch=%d, targetLength=%d, strategy=%d \n", params->minMatch, params->targetLength, params->strategy);
+    if (stringPtr[0] != 0) return 0; /* check the end of string */
+    return 1;
+}
+
+static void printVersion(void)
+{
+    DISPLAYOUT(WELCOME_MESSAGE);
+    if (g_displayLevel >= 3) {
+    /* format support */
+        DISPLAYOUT("*** supports: zstd");
+    #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>0) && (ZSTD_LEGACY_SUPPORT<8)
+        DISPLAYOUT(", zstd legacy v0.%d+", ZSTD_LEGACY_SUPPORT);
+    #endif
+    #ifdef ZSTD_GZCOMPRESS
+        DISPLAYOUT(", gzip");
+    #endif
+    #ifdef ZSTD_LZ4COMPRESS
+        DISPLAYOUT(", lz4");
+    #endif
+    #ifdef ZSTD_LZMACOMPRESS
+        DISPLAYOUT(", lzma, xz ");
+    #endif
+        DISPLAYOUT("\n");
+        if (g_displayLevel >= 4) {
+            /* posix support */
+        #ifdef _POSIX_C_SOURCE
+            DISPLAYOUT("_POSIX_C_SOURCE defined: %ldL\n", (long) _POSIX_C_SOURCE);
+        #endif
+        #ifdef _POSIX_VERSION
+            DISPLAYOUT("_POSIX_VERSION defined: %ldL \n", (long) _POSIX_VERSION);
+        #endif
+        #ifdef PLATFORM_POSIX_VERSION
+            DISPLAYOUT("PLATFORM_POSIX_VERSION defined: %ldL\n", (long) PLATFORM_POSIX_VERSION);
+        #endif
+    }   }
+}
+
+/* Environment variables for parameter setting */
+#define ENV_CLEVEL "ZSTD_CLEVEL"
+
+/* pick up environment variable */
+static int init_cLevel(void) {
+    const char* const env = getenv(ENV_CLEVEL);
+    if (env != NULL) {
+        const char* ptr = env;
+        int sign = 1;
+        if (*ptr == '-') {
+            sign = -1;
+            ptr++;
+        } else if (*ptr == '+') {
+            ptr++;
+        }
+
+        if ((*ptr>='0') && (*ptr<='9')) {
+            unsigned absLevel;
+            if (readU32FromCharChecked(&ptr, &absLevel)) {
+                DISPLAYLEVEL(2, "Ignore environment variable setting %s=%s: numeric value too large \n", ENV_CLEVEL, env);
+                return ZSTDCLI_CLEVEL_DEFAULT;
+            } else if (*ptr == 0) {
+                return sign * (int)absLevel;
+        }   }
+
+        DISPLAYLEVEL(2, "Ignore environment variable setting %s=%s: not a valid integer value \n", ENV_CLEVEL, env);
+    }
+
+    return ZSTDCLI_CLEVEL_DEFAULT;
+}
+
+#define ZSTD_NB_STRATEGIES 9
+
+static const char* ZSTD_strategyMap[ZSTD_NB_STRATEGIES + 1] = { "", "ZSTD_fast",
+                "ZSTD_dfast", "ZSTD_greedy", "ZSTD_lazy", "ZSTD_lazy2", "ZSTD_btlazy2",
+                "ZSTD_btopt", "ZSTD_btultra", "ZSTD_btultra2"};
+
+typedef enum { zom_compress, zom_decompress, zom_test, zom_bench, zom_train, zom_list } zstd_operation_mode;
+
+#define CLEAN_RETURN(i) { operationResult = (i); goto _end; }
+
+#ifdef ZSTD_NOCOMPRESS
+/* symbols from compression library are not defined and should not be invoked */
+# define MINCLEVEL  -99
+# define MAXCLEVEL   22
+#else
+# define MINCLEVEL  ZSTD_minCLevel()
+# define MAXCLEVEL  ZSTD_maxCLevel()
+#endif
+
+int main(int const argCount, const char* argv[])
+{
+    int argNb,
+        followLinks = 0,
+        forceStdout = 0,
+        lastCommand = 0,
+        ldmFlag = 0,
+        main_pause = 0,
+        nbWorkers = 0,
+        adapt = 0,
+        adaptMin = MINCLEVEL,
+        adaptMax = MAXCLEVEL,
+        rsyncable = 0,
+        nextArgumentIsOutFileName = 0,
+        nextArgumentIsOutDirName = 0,
+        nextArgumentIsMaxDict = 0,
+        nextArgumentIsDictID = 0,
+        nextArgumentsAreFiles = 0,
+        nextEntryIsDictionary = 0,
+        operationResult = 0,
+        separateFiles = 0,
+        setRealTimePrio = 0,
+        singleThread = 0,
+        showDefaultCParams = 0,
+        ultra=0,
+        contentSize=1;
+    double compressibility = 0.5;
+    unsigned bench_nbSeconds = 3;   /* would be better if this value was synchronized from bench */
+    size_t blockSize = 0;
+
+    FIO_prefs_t* const prefs = FIO_createPreferences();
+    zstd_operation_mode operation = zom_compress;
+    ZSTD_compressionParameters compressionParams;
+    int cLevel = init_cLevel();
+    int cLevelLast = MINCLEVEL - 1;  /* lower than minimum */
+    unsigned recursive = 0;
+    unsigned memLimit = 0;
+    FileNamesTable* filenames = UTIL_allocateFileNamesTable((size_t)argCount);  /* argCount >= 1 */
+    FileNamesTable* file_of_names = UTIL_allocateFileNamesTable((size_t)argCount);  /* argCount >= 1 */
+    const char* programName = argv[0];
+    const char* outFileName = NULL;
+    const char* outDirName = NULL;
+    const char* dictFileName = NULL;
+    const char* patchFromDictFileName = NULL;
+    const char* suffix = ZSTD_EXTENSION;
+    unsigned maxDictSize = g_defaultMaxDictSize;
+    unsigned dictID = 0;
+    size_t streamSrcSize = 0;
+    size_t targetCBlockSize = 0;
+    size_t srcSizeHint = 0;
+    int dictCLevel = g_defaultDictCLevel;
+    unsigned dictSelect = g_defaultSelectivityLevel;
+#ifndef ZSTD_NODICT
+    ZDICT_cover_params_t coverParams = defaultCoverParams();
+    ZDICT_fastCover_params_t fastCoverParams = defaultFastCoverParams();
+    dictType dict = fastCover;
+#endif
+#ifndef ZSTD_NOBENCH
+    BMK_advancedParams_t benchParams = BMK_initAdvancedParams();
+#endif
+    ZSTD_literalCompressionMode_e literalCompressionMode = ZSTD_lcm_auto;
+
+
+    /* init */
+    (void)recursive; (void)cLevelLast;    /* not used when ZSTD_NOBENCH set */
+    (void)memLimit;
+    assert(argCount >= 1);
+    if ((filenames==NULL) || (file_of_names==NULL)) { DISPLAY("zstd: allocation error \n"); exit(1); }
+    programName = lastNameFromPath(programName);
+#ifdef ZSTD_MULTITHREAD
+    nbWorkers = 1;
+#endif
+
+    /* preset behaviors */
+    if (exeNameMatch(programName, ZSTD_ZSTDMT)) nbWorkers=0, singleThread=0;
+    if (exeNameMatch(programName, ZSTD_UNZSTD)) operation=zom_decompress;
+    if (exeNameMatch(programName, ZSTD_CAT)) { operation=zom_decompress; FIO_overwriteMode(prefs); forceStdout=1; followLinks=1; outFileName=stdoutmark; g_displayLevel=1; }     /* supports multiple formats */
+    if (exeNameMatch(programName, ZSTD_ZCAT)) { operation=zom_decompress; FIO_overwriteMode(prefs); forceStdout=1; followLinks=1; outFileName=stdoutmark; g_displayLevel=1; }    /* behave like zcat, also supports multiple formats */
+    if (exeNameMatch(programName, ZSTD_GZ)) { suffix = GZ_EXTENSION; FIO_setCompressionType(prefs, FIO_gzipCompression); FIO_setRemoveSrcFile(prefs, 1); }        /* behave like gzip */
+    if (exeNameMatch(programName, ZSTD_GUNZIP)) { operation=zom_decompress; FIO_setRemoveSrcFile(prefs, 1); }                                                     /* behave like gunzip, also supports multiple formats */
+    if (exeNameMatch(programName, ZSTD_GZCAT)) { operation=zom_decompress; FIO_overwriteMode(prefs); forceStdout=1; followLinks=1; outFileName=stdoutmark; g_displayLevel=1; }   /* behave like gzcat, also supports multiple formats */
+    if (exeNameMatch(programName, ZSTD_LZMA)) { suffix = LZMA_EXTENSION; FIO_setCompressionType(prefs, FIO_lzmaCompression); FIO_setRemoveSrcFile(prefs, 1); }    /* behave like lzma */
+    if (exeNameMatch(programName, ZSTD_UNLZMA)) { operation=zom_decompress; FIO_setCompressionType(prefs, FIO_lzmaCompression); FIO_setRemoveSrcFile(prefs, 1); } /* behave like unlzma, also supports multiple formats */
+    if (exeNameMatch(programName, ZSTD_XZ)) { suffix = XZ_EXTENSION; FIO_setCompressionType(prefs, FIO_xzCompression); FIO_setRemoveSrcFile(prefs, 1); }          /* behave like xz */
+    if (exeNameMatch(programName, ZSTD_UNXZ)) { operation=zom_decompress; FIO_setCompressionType(prefs, FIO_xzCompression); FIO_setRemoveSrcFile(prefs, 1); }     /* behave like unxz, also supports multiple formats */
+    if (exeNameMatch(programName, ZSTD_LZ4)) { suffix = LZ4_EXTENSION; FIO_setCompressionType(prefs, FIO_lz4Compression); }                                       /* behave like lz4 */
+    if (exeNameMatch(programName, ZSTD_UNLZ4)) { operation=zom_decompress; FIO_setCompressionType(prefs, FIO_lz4Compression); }                                   /* behave like unlz4, also supports multiple formats */
+    memset(&compressionParams, 0, sizeof(compressionParams));
+
+    /* init crash handler */
+    FIO_addAbortHandler();
+
+    /* command switches */
+    for (argNb=1; argNb<argCount; argNb++) {
+        const char* argument = argv[argNb];
+        if (!argument) continue;   /* Protection if argument empty */
+
+        if (nextArgumentsAreFiles) {
+            UTIL_refFilename(filenames, argument);
+            continue;
+        }
+
+        /* "-" means stdin/stdout */
+        if (!strcmp(argument, "-")){
+            UTIL_refFilename(filenames, stdinmark);
+            continue;
+        }
+
+        /* Decode commands (note : aggregated commands are allowed) */
+        if (argument[0]=='-') {
+
+            if (argument[1]=='-') {
+                /* long commands (--long-word) */
+                if (!strcmp(argument, "--")) { nextArgumentsAreFiles=1; continue; }   /* only file names allowed from now on */
+                if (!strcmp(argument, "--list")) { operation=zom_list; continue; }
+                if (!strcmp(argument, "--compress")) { operation=zom_compress; continue; }
+                if (!strcmp(argument, "--decompress")) { operation=zom_decompress; continue; }
+                if (!strcmp(argument, "--uncompress")) { operation=zom_decompress; continue; }
+                if (!strcmp(argument, "--force")) { FIO_overwriteMode(prefs); forceStdout=1; followLinks=1; continue; }
+                if (!strcmp(argument, "--version")) { printVersion(); CLEAN_RETURN(0); }
+                if (!strcmp(argument, "--help")) { usage_advanced(programName); CLEAN_RETURN(0); }
+                if (!strcmp(argument, "--verbose")) { g_displayLevel++; continue; }
+                if (!strcmp(argument, "--quiet")) { g_displayLevel--; continue; }
+                if (!strcmp(argument, "--stdout")) { forceStdout=1; outFileName=stdoutmark; g_displayLevel-=(g_displayLevel==2); continue; }
+                if (!strcmp(argument, "--ultra")) { ultra=1; continue; }
+                if (!strcmp(argument, "--check")) { FIO_setChecksumFlag(prefs, 2); continue; }
+                if (!strcmp(argument, "--no-check")) { FIO_setChecksumFlag(prefs, 0); continue; }
+                if (!strcmp(argument, "--sparse")) { FIO_setSparseWrite(prefs, 2); continue; }
+                if (!strcmp(argument, "--no-sparse")) { FIO_setSparseWrite(prefs, 0); continue; }
+                if (!strcmp(argument, "--test")) { operation=zom_test; continue; }
+                if (!strcmp(argument, "--train")) { operation=zom_train; if (outFileName==NULL) outFileName=g_defaultDictName; continue; }
+                if (!strcmp(argument, "--maxdict")) { nextArgumentIsMaxDict=1; lastCommand=1; continue; }  /* kept available for compatibility with old syntax ; will be removed one day */
+                if (!strcmp(argument, "--dictID")) { nextArgumentIsDictID=1; lastCommand=1; continue; }  /* kept available for compatibility with old syntax ; will be removed one day */
+                if (!strcmp(argument, "--no-dictID")) { FIO_setDictIDFlag(prefs, 0); continue; }
+                if (!strcmp(argument, "--keep")) { FIO_setRemoveSrcFile(prefs, 0); continue; }
+                if (!strcmp(argument, "--rm")) { FIO_setRemoveSrcFile(prefs, 1); continue; }
+                if (!strcmp(argument, "--priority=rt")) { setRealTimePrio = 1; continue; }
+                if (!strcmp(argument, "--output-dir-flat")) {nextArgumentIsOutDirName=1; lastCommand=1; continue; }
+                if (!strcmp(argument, "--show-default-cparams")) { showDefaultCParams = 1; continue; }
+                if (!strcmp(argument, "--content-size")) { contentSize = 1; continue; }
+                if (!strcmp(argument, "--no-content-size")) { contentSize = 0; continue; }
+                if (!strcmp(argument, "--adapt")) { adapt = 1; continue; }
+                if (longCommandWArg(&argument, "--adapt=")) { adapt = 1; if (!parseAdaptParameters(argument, &adaptMin, &adaptMax)) { badusage(programName); CLEAN_RETURN(1); } continue; }
+                if (!strcmp(argument, "--single-thread")) { nbWorkers = 0; singleThread = 1; continue; }
+                if (!strcmp(argument, "--format=zstd")) { suffix = ZSTD_EXTENSION; FIO_setCompressionType(prefs, FIO_zstdCompression); continue; }
+#ifdef ZSTD_GZCOMPRESS
+                if (!strcmp(argument, "--format=gzip")) { suffix = GZ_EXTENSION; FIO_setCompressionType(prefs, FIO_gzipCompression); continue; }
+#endif
+#ifdef ZSTD_LZMACOMPRESS
+                if (!strcmp(argument, "--format=lzma")) { suffix = LZMA_EXTENSION; FIO_setCompressionType(prefs, FIO_lzmaCompression);  continue; }
+                if (!strcmp(argument, "--format=xz")) { suffix = XZ_EXTENSION; FIO_setCompressionType(prefs, FIO_xzCompression);  continue; }
+#endif
+#ifdef ZSTD_LZ4COMPRESS
+                if (!strcmp(argument, "--format=lz4")) { suffix = LZ4_EXTENSION; FIO_setCompressionType(prefs, FIO_lz4Compression);  continue; }
+#endif
+                if (!strcmp(argument, "--rsyncable")) { rsyncable = 1; continue; }
+                if (!strcmp(argument, "--compress-literals")) { literalCompressionMode = ZSTD_lcm_huffman; continue; }
+                if (!strcmp(argument, "--no-compress-literals")) { literalCompressionMode = ZSTD_lcm_uncompressed; continue; }
+                if (!strcmp(argument, "--no-progress")) { FIO_setNoProgress(1); continue; }
+                if (!strcmp(argument, "--exclude-compressed")) { FIO_setExcludeCompressedFile(prefs, 1); continue; }
+                /* long commands with arguments */
+#ifndef ZSTD_NODICT
+                if (longCommandWArg(&argument, "--train-cover")) {
+                  operation = zom_train;
+                  if (outFileName == NULL)
+                      outFileName = g_defaultDictName;
+                  dict = cover;
+                  /* Allow optional arguments following an = */
+                  if (*argument == 0) { memset(&coverParams, 0, sizeof(coverParams)); }
+                  else if (*argument++ != '=') { badusage(programName); CLEAN_RETURN(1); }
+                  else if (!parseCoverParameters(argument, &coverParams)) { badusage(programName); CLEAN_RETURN(1); }
+                  continue;
+                }
+                if (longCommandWArg(&argument, "--train-fastcover")) {
+                  operation = zom_train;
+                  if (outFileName == NULL)
+                      outFileName = g_defaultDictName;
+                  dict = fastCover;
+                  /* Allow optional arguments following an = */
+                  if (*argument == 0) { memset(&fastCoverParams, 0, sizeof(fastCoverParams)); }
+                  else if (*argument++ != '=') { badusage(programName); CLEAN_RETURN(1); }
+                  else if (!parseFastCoverParameters(argument, &fastCoverParams)) { badusage(programName); CLEAN_RETURN(1); }
+                  continue;
+                }
+                if (longCommandWArg(&argument, "--train-legacy")) {
+                  operation = zom_train;
+                  if (outFileName == NULL)
+                      outFileName = g_defaultDictName;
+                  dict = legacy;
+                  /* Allow optional arguments following an = */
+                  if (*argument == 0) { continue; }
+                  else if (*argument++ != '=') { badusage(programName); CLEAN_RETURN(1); }
+                  else if (!parseLegacyParameters(argument, &dictSelect)) { badusage(programName); CLEAN_RETURN(1); }
+                  continue;
+                }
+#endif
+                if (longCommandWArg(&argument, "--threads=")) { nbWorkers = (int)readU32FromChar(&argument); continue; }
+                if (longCommandWArg(&argument, "--memlimit=")) { memLimit = readU32FromChar(&argument); continue; }
+                if (longCommandWArg(&argument, "--memory=")) { memLimit = readU32FromChar(&argument); continue; }
+                if (longCommandWArg(&argument, "--memlimit-decompress=")) { memLimit = readU32FromChar(&argument); continue; }
+                if (longCommandWArg(&argument, "--block-size=")) { blockSize = readSizeTFromChar(&argument); continue; }
+                if (longCommandWArg(&argument, "--maxdict=")) { maxDictSize = readU32FromChar(&argument); continue; }
+                if (longCommandWArg(&argument, "--dictID=")) { dictID = readU32FromChar(&argument); continue; }
+                if (longCommandWArg(&argument, "--zstd=")) { if (!parseCompressionParameters(argument, &compressionParams)) { badusage(programName); CLEAN_RETURN(1); } continue; }
+                if (longCommandWArg(&argument, "--stream-size=")) { streamSrcSize = readSizeTFromChar(&argument); continue; }
+                if (longCommandWArg(&argument, "--target-compressed-block-size=")) { targetCBlockSize = readSizeTFromChar(&argument); continue; }
+                if (longCommandWArg(&argument, "--size-hint=")) { srcSizeHint = readSizeTFromChar(&argument); continue; }
+                if (longCommandWArg(&argument, "--output-dir-flat=")) { outDirName = argument; continue; }
+                if (longCommandWArg(&argument, "--patch-from=")) { patchFromDictFileName = argument; continue; }
+                if (longCommandWArg(&argument, "--long")) {
+                    unsigned ldmWindowLog = 0;
+                    ldmFlag = 1;
+                    /* Parse optional window log */
+                    if (*argument == '=') {
+                        ++argument;
+                        ldmWindowLog = readU32FromChar(&argument);
+                    } else if (*argument != 0) {
+                        /* Invalid character following --long */
+                        badusage(programName);
+                        CLEAN_RETURN(1);
+                    }
+                    /* Only set windowLog if not already set by --zstd */
+                    if (compressionParams.windowLog == 0)
+                        compressionParams.windowLog = ldmWindowLog;
+                    continue;
+                }
+#ifndef ZSTD_NOCOMPRESS   /* linking ZSTD_minCLevel() requires compression support */
+                if (longCommandWArg(&argument, "--fast")) {
+                    /* Parse optional acceleration factor */
+                    if (*argument == '=') {
+                        U32 const maxFast = (U32)-ZSTD_minCLevel();
+                        U32 fastLevel;
+                        ++argument;
+                        fastLevel = readU32FromChar(&argument);
+                        if (fastLevel > maxFast) fastLevel = maxFast;
+                        if (fastLevel) {
+                            dictCLevel = cLevel = -(int)fastLevel;
+                        } else {
+                            badusage(programName);
+                            CLEAN_RETURN(1);
+                        }
+                    } else if (*argument != 0) {
+                        /* Invalid character following --fast */
+                        badusage(programName);
+                        CLEAN_RETURN(1);
+                    } else {
+                        cLevel = -1;  /* default for --fast */
+                    }
+                    continue;
+                }
+#endif
+
+                if (longCommandWArg(&argument, "--filelist=")) {
+                    UTIL_refFilename(file_of_names, argument);
+                    continue;
+                }
+
+                /* fall-through, will trigger bad_usage() later on */
+            }
+
+            argument++;
+            while (argument[0]!=0) {
+                if (lastCommand) {
+                    DISPLAY("error : command must be followed by argument \n");
+                    CLEAN_RETURN(1);
+                }
+#ifndef ZSTD_NOCOMPRESS
+                /* compression Level */
+                if ((*argument>='0') && (*argument<='9')) {
+                    dictCLevel = cLevel = (int)readU32FromChar(&argument);
+                    continue;
+                }
+#endif
+
+                switch(argument[0])
+                {
+                    /* Display help */
+                case 'V': printVersion(); CLEAN_RETURN(0);   /* Version Only */
+                case 'H':
+                case 'h': usage_advanced(programName); CLEAN_RETURN(0);
+
+                     /* Compress */
+                case 'z': operation=zom_compress; argument++; break;
+
+                     /* Decoding */
+                case 'd':
+#ifndef ZSTD_NOBENCH
+                        benchParams.mode = BMK_decodeOnly;
+                        if (operation==zom_bench) { argument++; break; }  /* benchmark decode (hidden option) */
+#endif
+                        operation=zom_decompress; argument++; break;
+
+                    /* Force stdout, even if stdout==console */
+                case 'c': forceStdout=1; outFileName=stdoutmark; argument++; break;
+
+                    /* Use file content as dictionary */
+                case 'D': nextEntryIsDictionary = 1; lastCommand = 1; argument++; break;
+
+                    /* Overwrite */
+                case 'f': FIO_overwriteMode(prefs); forceStdout=1; followLinks=1; argument++; break;
+
+                    /* Verbose mode */
+                case 'v': g_displayLevel++; argument++; break;
+
+                    /* Quiet mode */
+                case 'q': g_displayLevel--; argument++; break;
+
+                    /* keep source file (default) */
+                case 'k': FIO_setRemoveSrcFile(prefs, 0); argument++; break;
+
+                    /* Checksum */
+                case 'C': FIO_setChecksumFlag(prefs, 2); argument++; break;
+
+                    /* test compressed file */
+                case 't': operation=zom_test; argument++; break;
+
+                    /* destination file name */
+                case 'o': nextArgumentIsOutFileName=1; lastCommand=1; argument++; break;
+
+                    /* limit memory */
+                case 'M':
+                    argument++;
+                    memLimit = readU32FromChar(&argument);
+                    break;
+                case 'l': operation=zom_list; argument++; break;
+#ifdef UTIL_HAS_CREATEFILELIST
+                    /* recursive */
+                case 'r': recursive=1; argument++; break;
+#endif
+
+#ifndef ZSTD_NOBENCH
+                    /* Benchmark */
+                case 'b':
+                    operation=zom_bench;
+                    argument++;
+                    break;
+
+                    /* range bench (benchmark only) */
+                case 'e':
+                    /* compression Level */
+                    argument++;
+                    cLevelLast = (int)readU32FromChar(&argument);
+                    break;
+
+                    /* Modify Nb Iterations (benchmark only) */
+                case 'i':
+                    argument++;
+                    bench_nbSeconds = readU32FromChar(&argument);
+                    break;
+
+                    /* cut input into blocks (benchmark only) */
+                case 'B':
+                    argument++;
+                    blockSize = readU32FromChar(&argument);
+                    break;
+
+                    /* benchmark files separately (hidden option) */
+                case 'S':
+                    argument++;
+                    separateFiles = 1;
+                    break;
+
+#endif   /* ZSTD_NOBENCH */
+
+                    /* nb of threads (hidden option) */
+                case 'T':
+                    argument++;
+                    nbWorkers = (int)readU32FromChar(&argument);
+                    break;
+
+                    /* Dictionary Selection level */
+                case 's':
+                    argument++;
+                    dictSelect = readU32FromChar(&argument);
+                    break;
+
+                    /* Pause at the end (-p) or set an additional param (-p#) (hidden option) */
+                case 'p': argument++;
+#ifndef ZSTD_NOBENCH
+                    if ((*argument>='0') && (*argument<='9')) {
+                        benchParams.additionalParam = (int)readU32FromChar(&argument);
+                    } else
+#endif
+                        main_pause=1;
+                    break;
+
+                    /* Select compressibility of synthetic sample */
+                case 'P':
+                {   argument++;
+                    compressibility = (double)readU32FromChar(&argument) / 100;
+                }
+                break;
+
+                    /* unknown command */
+                default : badusage(programName); CLEAN_RETURN(1);
+                }
+            }
+            continue;
+        }   /* if (argument[0]=='-') */
+
+        if (nextArgumentIsMaxDict) {  /* kept available for compatibility with old syntax ; will be removed one day */
+            nextArgumentIsMaxDict = 0;
+            lastCommand = 0;
+            maxDictSize = readU32FromChar(&argument);
+            continue;
+        }
+
+        if (nextArgumentIsDictID) {  /* kept available for compatibility with old syntax ; will be removed one day */
+            nextArgumentIsDictID = 0;
+            lastCommand = 0;
+            dictID = readU32FromChar(&argument);
+            continue;
+        }
+
+        if (nextEntryIsDictionary) {
+            nextEntryIsDictionary = 0;
+            lastCommand = 0;
+            dictFileName = argument;
+            continue;
+        }
+
+        if (nextArgumentIsOutFileName) {
+            nextArgumentIsOutFileName = 0;
+            lastCommand = 0;
+            outFileName = argument;
+            if (!strcmp(outFileName, "-")) outFileName = stdoutmark;
+            continue;
+        }
+
+        if (nextArgumentIsOutDirName) {
+            nextArgumentIsOutDirName = 0;
+            lastCommand = 0;
+            outDirName = argument;
+            continue;
+        }
+
+        /* none of the above : add filename to list */
+        UTIL_refFilename(filenames, argument);
+    }
+
+    if (lastCommand) { /* forgotten argument */
+        DISPLAY("error : command must be followed by argument \n");
+        CLEAN_RETURN(1);
+    }
+
+    /* Welcome message (if verbose) */
+    DISPLAYLEVEL(3, WELCOME_MESSAGE);
+
+#ifdef ZSTD_MULTITHREAD
+    if ((nbWorkers==0) && (!singleThread)) {
+        /* automatically set # workers based on # of reported cpus */
+        nbWorkers = UTIL_countPhysicalCores();
+        DISPLAYLEVEL(3, "Note: %d physical core(s) detected \n", nbWorkers);
+    }
+#else
+    (void)singleThread; (void)nbWorkers;
+#endif
+
+#ifdef UTIL_HAS_CREATEFILELIST
+    g_utilDisplayLevel = g_displayLevel;
+    if (!followLinks) {
+        unsigned u, fileNamesNb;
+        unsigned const nbFilenames = (unsigned)filenames->tableSize;
+        for (u=0, fileNamesNb=0; u<nbFilenames; u++) {
+            if ( UTIL_isLink(filenames->fileNames[u])
+             && !UTIL_isFIFO(filenames->fileNames[u])
+            ) {
+                DISPLAYLEVEL(2, "Warning : %s is a symbolic link, ignoring \n", filenames->fileNames[u]);
+            } else {
+                filenames->fileNames[fileNamesNb++] = filenames->fileNames[u];
+        }   }
+        if (fileNamesNb == 0 && nbFilenames > 0)  /* all names are eliminated */
+            CLEAN_RETURN(1);
+        filenames->tableSize = fileNamesNb;
+    }   /* if (!followLinks) */
+
+    /* read names from a file */
+    if (file_of_names->tableSize) {
+        size_t const nbFileLists = file_of_names->tableSize;
+        size_t flNb;
+        for (flNb=0; flNb < nbFileLists; flNb++) {
+            FileNamesTable* const fnt = UTIL_createFileNamesTable_fromFileName(file_of_names->fileNames[flNb]);
+            if (fnt==NULL) {
+                DISPLAYLEVEL(1, "zstd: error reading %s \n", file_of_names->fileNames[flNb]);
+                CLEAN_RETURN(1);
+            }
+            filenames = UTIL_mergeFileNamesTable(filenames, fnt);
+        }
+    }
+
+    if (recursive) {  /* at this stage, filenameTable is a list of paths, which can contain both files and directories */
+        UTIL_expandFNT(&filenames, followLinks);
+    }
+#else
+    (void)followLinks;
+#endif
+
+    if (operation == zom_list) {
+#ifndef ZSTD_NODECOMPRESS
+        int const ret = FIO_listMultipleFiles((unsigned)filenames->tableSize, filenames->fileNames, g_displayLevel);
+        CLEAN_RETURN(ret);
+#else
+        DISPLAY("file information is not supported \n");
+        CLEAN_RETURN(1);
+#endif
+    }
+
+    /* Check if benchmark is selected */
+    if (operation==zom_bench) {
+#ifndef ZSTD_NOBENCH
+        benchParams.blockSize = blockSize;
+        benchParams.nbWorkers = nbWorkers;
+        benchParams.realTime = (unsigned)setRealTimePrio;
+        benchParams.nbSeconds = bench_nbSeconds;
+        benchParams.ldmFlag = ldmFlag;
+        benchParams.ldmMinMatch = (int)g_ldmMinMatch;
+        benchParams.ldmHashLog = (int)g_ldmHashLog;
+        if (g_ldmBucketSizeLog != LDM_PARAM_DEFAULT) {
+            benchParams.ldmBucketSizeLog = (int)g_ldmBucketSizeLog;
+        }
+        if (g_ldmHashRateLog != LDM_PARAM_DEFAULT) {
+            benchParams.ldmHashRateLog = (int)g_ldmHashRateLog;
+        }
+        benchParams.literalCompressionMode = literalCompressionMode;
+
+        if (cLevel > ZSTD_maxCLevel()) cLevel = ZSTD_maxCLevel();
+        if (cLevelLast > ZSTD_maxCLevel()) cLevelLast = ZSTD_maxCLevel();
+        if (cLevelLast < cLevel) cLevelLast = cLevel;
+        if (cLevelLast > cLevel)
+            DISPLAYLEVEL(3, "Benchmarking levels from %d to %d\n", cLevel, cLevelLast);
+        if (filenames->tableSize > 0) {
+            if(separateFiles) {
+                unsigned i;
+                for(i = 0; i < filenames->tableSize; i++) {
+                    int c;
+                    DISPLAYLEVEL(3, "Benchmarking %s \n", filenames->fileNames[i]);
+                    for(c = cLevel; c <= cLevelLast; c++) {
+                        BMK_benchFilesAdvanced(&filenames->fileNames[i], 1, dictFileName, c, &compressionParams, g_displayLevel, &benchParams);
+                }   }
+            } else {
+                for(; cLevel <= cLevelLast; cLevel++) {
+                    BMK_benchFilesAdvanced(filenames->fileNames, (unsigned)filenames->tableSize, dictFileName, cLevel, &compressionParams, g_displayLevel, &benchParams);
+            }   }
+        } else {
+            for(; cLevel <= cLevelLast; cLevel++) {
+                BMK_syntheticTest(cLevel, compressibility, &compressionParams, g_displayLevel, &benchParams);
+        }   }
+
+#else
+        (void)bench_nbSeconds; (void)blockSize; (void)setRealTimePrio; (void)separateFiles; (void)compressibility;
+#endif
+        goto _end;
+    }
+
+    /* Check if dictionary builder is selected */
+    if (operation==zom_train) {
+#ifndef ZSTD_NODICT
+        ZDICT_params_t zParams;
+        zParams.compressionLevel = dictCLevel;
+        zParams.notificationLevel = (unsigned)g_displayLevel;
+        zParams.dictID = dictID;
+        if (dict == cover) {
+            int const optimize = !coverParams.k || !coverParams.d;
+            coverParams.nbThreads = (unsigned)nbWorkers;
+            coverParams.zParams = zParams;
+            operationResult = DiB_trainFromFiles(outFileName, maxDictSize, filenames->fileNames, (unsigned)filenames->tableSize, blockSize, NULL, &coverParams, NULL, optimize);
+        } else if (dict == fastCover) {
+            int const optimize = !fastCoverParams.k || !fastCoverParams.d;
+            fastCoverParams.nbThreads = (unsigned)nbWorkers;
+            fastCoverParams.zParams = zParams;
+            operationResult = DiB_trainFromFiles(outFileName, maxDictSize, filenames->fileNames, (unsigned)filenames->tableSize, blockSize, NULL, NULL, &fastCoverParams, optimize);
+        } else {
+            ZDICT_legacy_params_t dictParams;
+            memset(&dictParams, 0, sizeof(dictParams));
+            dictParams.selectivityLevel = dictSelect;
+            dictParams.zParams = zParams;
+            operationResult = DiB_trainFromFiles(outFileName, maxDictSize, filenames->fileNames, (unsigned)filenames->tableSize, blockSize, &dictParams, NULL, NULL, 0);
+        }
+#else
+        (void)dictCLevel; (void)dictSelect; (void)dictID;  (void)maxDictSize; /* not used when ZSTD_NODICT set */
+        DISPLAYLEVEL(1, "training mode not available \n");
+        operationResult = 1;
+#endif
+        goto _end;
+    }
+
+#ifndef ZSTD_NODECOMPRESS
+    if (operation==zom_test) { FIO_setTestMode(prefs, 1); outFileName=nulmark; FIO_setRemoveSrcFile(prefs, 0); }  /* test mode */
+#endif
+
+    /* No input filename ==> use stdin and stdout */
+    if (filenames->tableSize == 0) UTIL_refFilename(filenames, stdinmark);
+    if (!strcmp(filenames->fileNames[0], stdinmark) && !outFileName)
+        outFileName = stdoutmark;  /* when input is stdin, default output is stdout */
+
+    /* Check if input/output defined as console; trigger an error in this case */
+    if (!strcmp(filenames->fileNames[0], stdinmark) && IS_CONSOLE(stdin) ) {
+        badusage(programName);
+        CLEAN_RETURN(1);
+    }
+    if ( outFileName && !strcmp(outFileName, stdoutmark)
+      && IS_CONSOLE(stdout)
+      && !strcmp(filenames->fileNames[0], stdinmark)
+      && !forceStdout
+      && operation!=zom_decompress ) {
+        badusage(programName);
+        CLEAN_RETURN(1);
+    }
+
+#ifndef ZSTD_NOCOMPRESS
+    /* check compression level limits */
+    {   int const maxCLevel = ultra ? ZSTD_maxCLevel() : ZSTDCLI_CLEVEL_MAX;
+        if (cLevel > maxCLevel) {
+            DISPLAYLEVEL(2, "Warning : compression level higher than max, reduced to %i \n", maxCLevel);
+            cLevel = maxCLevel;
+    }   }
+#endif
+
+    if (showDefaultCParams) {
+        if (operation == zom_decompress) {
+            DISPLAY("error : can't use --show-default-cparams in decomrpession mode \n");
+            CLEAN_RETURN(1);
+        }
+    }
+
+    if (dictFileName != NULL && patchFromDictFileName != NULL) {
+        DISPLAY("error : can't use -D and --patch-from=# at the same time \n");
+        CLEAN_RETURN(1);
+    }
+
+    if (patchFromDictFileName != NULL && filenames->tableSize > 1) {
+        DISPLAY("error : can't use --patch-from=# on multiple files \n");
+        CLEAN_RETURN(1);
+    }
+
+    /* No status message in pipe mode (stdin - stdout) or multi-files mode */
+    if (!strcmp(filenames->fileNames[0], stdinmark) && outFileName && !strcmp(outFileName,stdoutmark) && (g_displayLevel==2)) g_displayLevel=1;
+    if ((filenames->tableSize > 1) & (g_displayLevel==2)) g_displayLevel=1;
+
+    /* IO Stream/File */
+    FIO_setNotificationLevel(g_displayLevel);
+    FIO_setPatchFromMode(prefs, patchFromDictFileName != NULL);
+    if (memLimit == 0) {
+        if (compressionParams.windowLog == 0) {
+            memLimit = (U32)1 << g_defaultMaxWindowLog;
+        } else {
+            memLimit = (U32)1 << (compressionParams.windowLog & 31);
+    }   }
+    if (patchFromDictFileName != NULL)
+        dictFileName = patchFromDictFileName;
+    FIO_setMemLimit(prefs, memLimit);
+    if (operation==zom_compress) {
+#ifndef ZSTD_NOCOMPRESS
+        FIO_setContentSize(prefs, contentSize);
+        FIO_setNbWorkers(prefs, nbWorkers);
+        FIO_setBlockSize(prefs, (int)blockSize);
+        if (g_overlapLog!=OVERLAP_LOG_DEFAULT) FIO_setOverlapLog(prefs, (int)g_overlapLog);
+        FIO_setLdmFlag(prefs, (unsigned)ldmFlag);
+        FIO_setLdmHashLog(prefs, (int)g_ldmHashLog);
+        FIO_setLdmMinMatch(prefs, (int)g_ldmMinMatch);
+        if (g_ldmBucketSizeLog != LDM_PARAM_DEFAULT) FIO_setLdmBucketSizeLog(prefs, (int)g_ldmBucketSizeLog);
+        if (g_ldmHashRateLog != LDM_PARAM_DEFAULT) FIO_setLdmHashRateLog(prefs, (int)g_ldmHashRateLog);
+        FIO_setAdaptiveMode(prefs, (unsigned)adapt);
+        FIO_setAdaptMin(prefs, adaptMin);
+        FIO_setAdaptMax(prefs, adaptMax);
+        FIO_setRsyncable(prefs, rsyncable);
+        FIO_setStreamSrcSize(prefs, streamSrcSize);
+        FIO_setTargetCBlockSize(prefs, targetCBlockSize);
+        FIO_setSrcSizeHint(prefs, srcSizeHint);
+        FIO_setLiteralCompressionMode(prefs, literalCompressionMode);
+        if (adaptMin > cLevel) cLevel = adaptMin;
+        if (adaptMax < cLevel) cLevel = adaptMax;
+
+        /* Compare strategies constant with the ground truth */
+        { ZSTD_bounds strategyBounds = ZSTD_cParam_getBounds(ZSTD_c_strategy);
+          assert(ZSTD_NB_STRATEGIES == strategyBounds.upperBound);
+          (void)strategyBounds; }
+
+        if (showDefaultCParams) {
+            size_t fileNb;
+            for (fileNb = 0; fileNb < (size_t)filenames->tableSize; fileNb++) {
+                unsigned long long fileSize = UTIL_getFileSize(filenames->fileNames[fileNb]);
+                const size_t dictSize = dictFileName != NULL ? (size_t)UTIL_getFileSize(dictFileName) : 0;
+                const ZSTD_compressionParameters cParams = ZSTD_getCParams(cLevel, fileSize, dictSize);
+                if (fileSize != UTIL_FILESIZE_UNKNOWN) DISPLAY("%s (%u bytes)\n", filenames->fileNames[fileNb], (unsigned)fileSize);
+                else DISPLAY("%s (src size unknown)\n", filenames->fileNames[fileNb]);
+                DISPLAY(" - windowLog     : %u\n", cParams.windowLog);
+                DISPLAY(" - chainLog      : %u\n", cParams.chainLog);
+                DISPLAY(" - hashLog       : %u\n", cParams.hashLog);
+                DISPLAY(" - searchLog     : %u\n", cParams.searchLog);
+                DISPLAY(" - minMatch      : %u\n", cParams.minMatch);
+                DISPLAY(" - targetLength  : %u\n", cParams.targetLength);
+                assert(cParams.strategy < ZSTD_NB_STRATEGIES + 1);
+                DISPLAY(" - strategy      : %s (%u)\n", ZSTD_strategyMap[(int)cParams.strategy], (unsigned)cParams.strategy);
+            }
+        }
+
+        if ((filenames->tableSize==1) && outFileName)
+          operationResult = FIO_compressFilename(prefs, outFileName, filenames->fileNames[0], dictFileName, cLevel, compressionParams);
+        else
+          operationResult = FIO_compressMultipleFilenames(prefs, filenames->fileNames, (unsigned)filenames->tableSize, outDirName, outFileName, suffix, dictFileName, cLevel, compressionParams);
+#else
+        (void)contentSize; (void)suffix; (void)adapt; (void)rsyncable; (void)ultra; (void)cLevel; (void)ldmFlag; (void)literalCompressionMode; (void)targetCBlockSize; (void)streamSrcSize; (void)srcSizeHint; (void)ZSTD_strategyMap; /* not used when ZSTD_NOCOMPRESS set */
+        DISPLAY("Compression not supported \n");
+#endif
+    } else {  /* decompression or test */
+#ifndef ZSTD_NODECOMPRESS
+        if (filenames->tableSize == 1 && outFileName) {
+            operationResult = FIO_decompressFilename(prefs, outFileName, filenames->fileNames[0], dictFileName);
+        } else {
+            operationResult = FIO_decompressMultipleFilenames(prefs, filenames->fileNames, (unsigned)filenames->tableSize, outDirName, outFileName, dictFileName);
+        }
+#else
+        DISPLAY("Decompression not supported \n");
+#endif
+    }
+
+_end:
+    FIO_freePreferences(prefs);
+    if (main_pause) waitEnter();
+    UTIL_freeFileNamesTable(filenames);
+    UTIL_freeFileNamesTable(file_of_names);
+
+    return operationResult;
+}
diff --git a/src/zstd/programs/zstdgrep b/src/zstd/programs/zstdgrep
new file mode 100755
index 000000000..61efaa947
--- /dev/null
+++ b/src/zstd/programs/zstdgrep
@@ -0,0 +1,134 @@
+#!/bin/sh
+#
+# Copyright (c) 2003 Thomas Klausner.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+grep=${GREP:-grep}
+zcat=${ZCAT:-zstdcat}
+
+endofopts=0
+pattern_found=0
+grep_args=""
+hyphen=0
+silent=0
+
+prog=${0##*/}
+
+# handle being called 'zegrep' or 'zfgrep'
+case $prog in
+    *egrep*) prog=zegrep; grep_args='-E';;
+    *fgrep*) prog=zfgrep; grep_args='-F';;
+    *)       prog=zstdgrep;;
+esac
+
+# skip all options and pass them on to grep taking care of options
+# with arguments, and if -e was supplied
+
+while [ "$#" -gt 0 ] && [ "${endofopts}" -eq 0 ]; do
+    case "$1" in
+    # from GNU grep-2.5.1 -- keep in sync!
+        -[ABCDXdefm])
+            if [ "$#" -lt 2 ]; then
+                printf '%s: missing argument for %s flag\n' "${prog}" "$1" >&2
+                exit 1
+            fi
+            case "$1" in
+                -e)
+                    pattern="$2"
+                    pattern_found=1
+                    shift 2
+                    break
+                    ;;
+                -f)
+                    pattern_found=2
+                    ;;
+                *)
+                    ;;
+            esac
+            grep_args="${grep_args} $1 $2"
+            shift 2
+            ;;
+        --)
+            shift
+            endofopts=1
+            ;;
+        -)
+            hyphen=1
+            shift
+            ;;
+        -h)
+            silent=1
+            shift
+            ;;
+        -*)
+            grep_args="${grep_args} $1"
+            shift
+            ;;
+        *)
+            # pattern to grep for
+            endofopts=1
+            ;;
+    esac
+done
+
+# if no -e option was found, take next argument as grep-pattern
+if [ "${pattern_found}" -lt 1 ]; then
+    if [ "$#" -ge 1 ]; then
+        pattern="$1"
+        shift
+    elif [ "${hyphen}" -gt 0 ]; then
+        pattern="-"
+    else
+        printf '%s: missing pattern\n' "${prog}" >&2
+        exit 1
+    fi
+fi
+
+EXIT_CODE=0
+# call grep ...
+if [ "$#" -lt 1 ]; then
+    # ... on stdin
+    set -f # Disable file name generation (globbing).
+    # shellcheck disable=SC2086
+    "${zcat}" - | "${grep}" ${grep_args} -- "${pattern}" -
+    EXIT_CODE=$?
+    set +f
+else
+    # ... on all files given on the command line
+    if [ "${silent}" -lt 1 ] && [ "$#" -gt 1 ]; then
+        grep_args="-H ${grep_args}"
+    fi
+    set -f
+    while [ "$#" -gt 0 ]; do
+        # shellcheck disable=SC2086
+        if [ $pattern_found -eq 2 ]; then
+            "${zcat}" -- "$1" | "${grep}" --label="${1}" ${grep_args} -- -
+        else
+            "${zcat}" -- "$1" | "${grep}" --label="${1}" ${grep_args} -- "${pattern}" -
+        fi
+        [ "$?" -ne 0 ] && EXIT_CODE=1
+        shift
+    done
+    set +f
+fi
+
+exit "${EXIT_CODE}"
diff --git a/src/zstd/programs/zstdgrep.1 b/src/zstd/programs/zstdgrep.1
new file mode 100644
index 000000000..fe1d29bbb
--- /dev/null
+++ b/src/zstd/programs/zstdgrep.1
@@ -0,0 +1,23 @@
+.
+.TH "ZSTDGREP" "1" "May 2020" "zstd 1.4.5" "User Commands"
+.
+.SH "NAME"
+\fBzstdgrep\fR \- print lines matching a pattern in zstandard\-compressed files
+.
+.SH "SYNOPSIS"
+\fBzstdgrep\fR [\fIgrep\-flags\fR] [\-\-] \fIpattern\fR [\fIfiles\fR \.\.\.]
+.
+.SH "DESCRIPTION"
+\fBzstdgrep\fR runs \fBgrep (1)\fR on files or stdin, if no files argument is given, after decompressing them with \fBzstdcat (1)\fR\.
+.
+.P
+The grep\-flags and pattern arguments are passed on to \fBgrep (1)\fR\. If an \fB\-e\fR flag is found in the \fBgrep\-flags\fR, \fBzstdgrep\fR will not look for a pattern argument\.
+.
+.SH "EXIT STATUS"
+In case of missing arguments or missing pattern, 1 will be returned, otherwise 0\.
+.
+.SH "SEE ALSO"
+\fBzstd (1)\fR
+.
+.SH "AUTHORS"
+Thomas Klausner \fIwiz@NetBSD\.org\fR
diff --git a/src/zstd/programs/zstdgrep.1.md b/src/zstd/programs/zstdgrep.1.md
new file mode 100644
index 000000000..363ad4f99
--- /dev/null
+++ b/src/zstd/programs/zstdgrep.1.md
@@ -0,0 +1,26 @@
+zstdgrep(1) -- print lines matching a pattern in zstandard-compressed files
+============================================================================
+
+SYNOPSIS
+--------
+
+`zstdgrep` [*grep-flags*] [--] _pattern_ [_files_ ...]
+
+
+DESCRIPTION
+-----------
+`zstdgrep` runs `grep (1)` on files or stdin, if no files argument is given, after decompressing them with `zstdcat (1)`.
+
+The grep-flags and pattern arguments are passed on to `grep (1)`.  If an `-e` flag is found in the `grep-flags`, `zstdgrep` will not look for a pattern argument.
+
+EXIT STATUS
+-----------
+In case of missing arguments or missing pattern, 1 will be returned, otherwise 0.
+
+SEE ALSO
+--------
+`zstd (1)`
+
+AUTHORS
+-------
+Thomas Klausner <wiz@NetBSD.org>
diff --git a/src/zstd/programs/zstdless b/src/zstd/programs/zstdless
new file mode 100755
index 000000000..893799e7d
--- /dev/null
+++ b/src/zstd/programs/zstdless
@@ -0,0 +1,2 @@
+#!/bin/sh
+zstdcat "$@" | less
diff --git a/src/zstd/programs/zstdless.1 b/src/zstd/programs/zstdless.1
new file mode 100644
index 000000000..d54c6400c
--- /dev/null
+++ b/src/zstd/programs/zstdless.1
@@ -0,0 +1,14 @@
+.
+.TH "ZSTDLESS" "1" "May 2020" "zstd 1.4.5" "User Commands"
+.
+.SH "NAME"
+\fBzstdless\fR \- view zstandard\-compressed files
+.
+.SH "SYNOPSIS"
+\fBzstdless\fR [\fIflags\fR] [\fIfile\fR \.\.\.]
+.
+.SH "DESCRIPTION"
+\fBzstdless\fR runs \fBless (1)\fR on files or stdin, if no files argument is given, after decompressing them with \fBzstdcat (1)\fR\.
+.
+.SH "SEE ALSO"
+\fBzstd (1)\fR
diff --git a/src/zstd/programs/zstdless.1.md b/src/zstd/programs/zstdless.1.md
new file mode 100644
index 000000000..d91d48abc
--- /dev/null
+++ b/src/zstd/programs/zstdless.1.md
@@ -0,0 +1,16 @@
+zstdless(1) -- view zstandard-compressed files
+============================================================================
+
+SYNOPSIS
+--------
+
+`zstdless` [*flags*] [_file_ ...]
+
+
+DESCRIPTION
+-----------
+`zstdless` runs `less (1)` on files or stdin, if no files argument is given, after decompressing them with `zstdcat (1)`.
+
+SEE ALSO
+--------
+`zstd (1)`