Adding upstream version 14.2.21.upstream/14.2.21upstream

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

17 files changed, 3569 insertions, 0 deletions

diff --git a/src/zstd/tests/fuzz/.gitignore b/src/zstd/tests/fuzz/.gitignore
new file mode 100644
index 00000000..4ff28de9
--- /dev/null
+++ b/src/zstd/tests/fuzz/.gitignore
@@ -0,0 +1,5 @@
+# test artefacts
+corpora
+block_decompress
+block_round_trip
+simple_round_trip
diff --git a/src/zstd/tests/fuzz/Makefile b/src/zstd/tests/fuzz/Makefile
new file mode 100644
index 00000000..d9b00fd2
--- /dev/null
+++ b/src/zstd/tests/fuzz/Makefile
@@ -0,0 +1,127 @@
+# ################################################################
+# Copyright (c) 2016-present, 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).
+# ################################################################
+
+# Optionally user defined flags
+CFLAGS ?= -O3
+CXXFLAGS ?= -O3
+CPPFLAGS ?=
+LDFLAGS ?=
+ARFLAGS ?=
+LIB_FUZZING_ENGINE ?= libregression.a
+PYTHON ?= python
+ifeq ($(shell uname), Darwin)
+	DOWNLOAD?=curl -L -o
+else
+	DOWNLOAD?=wget -O
+endif
+CORPORA_URL_PREFIX:=https://github.com/facebook/zstd/releases/download/fuzz-corpora/
+
+ZSTDDIR = ../../lib
+PRGDIR = ../../programs
+
+FUZZ_CPPFLAGS := -I$(ZSTDDIR) -I$(ZSTDDIR)/common -I$(ZSTDDIR)/compress \
+	-I$(ZSTDDIR)/dictBuilder -I$(ZSTDDIR)/deprecated -I$(PRGDIR) \
+	$(CPPFLAGS)
+FUZZ_EXTRA_FLAGS := -Wall -Wextra -Wcast-qual -Wcast-align -Wshadow \
+	-Wstrict-aliasing=1 -Wswitch-enum -Wdeclaration-after-statement \
+	-Wstrict-prototypes -Wundef -Wformat-security \
+	-Wvla -Wformat=2 -Winit-self -Wfloat-equal -Wwrite-strings \
+	-Wredundant-decls \
+	-g -fno-omit-frame-pointer
+FUZZ_CFLAGS := $(FUZZ_EXTRA_FLAGS) $(CFLAGS)
+FUZZ_CXXFLAGS := $(FUZZ_EXTRA_FLAGS) -std=c++11 $(CXXFLAGS)
+FUZZ_LDFLAGS := $(LDFLAGS)
+FUZZ_ARFLAGS := $(ARFLAGS)
+FUZZ_TARGET_FLAGS = $(FUZZ_CPPFLAGS) $(FUZZ_CXXFLAGS) $(FUZZ_LDFLAGS)
+
+FUZZ_HEADERS := fuzz_helpers.h fuzz.h zstd_helpers.h
+FUZZ_SRC := zstd_helpers.c
+
+ZSTDCOMMON_SRC := $(ZSTDDIR)/common/*.c
+ZSTDCOMP_SRC   := $(ZSTDDIR)/compress/*.c
+ZSTDDECOMP_SRC := $(ZSTDDIR)/decompress/*.c
+FUZZ_SRC       := \
+	$(FUZZ_SRC) \
+	$(ZSTDDECOMP_SRC) \
+	$(ZSTDCOMMON_SRC) \
+	$(ZSTDCOMP_SRC)
+
+FUZZ_OBJ := $(patsubst %.c,%.o, $(wildcard $(FUZZ_SRC)))
+
+
+.PHONY: default all clean cleanall
+
+default: all
+
+FUZZ_TARGETS :=       \
+	simple_round_trip \
+	stream_round_trip \
+	block_round_trip  \
+	simple_decompress \
+	stream_decompress \
+	block_decompress
+
+all: $(FUZZ_TARGETS)
+
+%.o: %.c
+	$(CC) $(FUZZ_CPPFLAGS) $(FUZZ_CFLAGS) $^ -c -o $@
+
+simple_round_trip: $(FUZZ_HEADERS) $(FUZZ_OBJ) simple_round_trip.o
+	$(CXX) $(FUZZ_TARGET_FLAGS) $(FUZZ_OBJ) simple_round_trip.o $(LIB_FUZZING_ENGINE) -o $@
+
+stream_round_trip: $(FUZZ_HEADERS) $(FUZZ_OBJ) stream_round_trip.o
+	$(CXX) $(FUZZ_TARGET_FLAGS) $(FUZZ_OBJ) stream_round_trip.o $(LIB_FUZZING_ENGINE) -o $@
+
+block_round_trip: $(FUZZ_HEADERS) $(FUZZ_OBJ) block_round_trip.o
+	$(CXX) $(FUZZ_TARGET_FLAGS) $(FUZZ_OBJ) block_round_trip.o $(LIB_FUZZING_ENGINE) -o $@
+
+simple_decompress: $(FUZZ_HEADERS) $(FUZZ_OBJ) simple_decompress.o
+	$(CXX) $(FUZZ_TARGET_FLAGS) $(FUZZ_OBJ) simple_decompress.o $(LIB_FUZZING_ENGINE) -o $@
+
+stream_decompress: $(FUZZ_HEADERS) $(FUZZ_OBJ) stream_decompress.o
+	$(CXX) $(FUZZ_TARGET_FLAGS) $(FUZZ_OBJ) stream_decompress.o $(LIB_FUZZING_ENGINE) -o $@
+
+block_decompress: $(FUZZ_HEADERS) $(FUZZ_OBJ) block_decompress.o
+	$(CXX) $(FUZZ_TARGET_FLAGS) $(FUZZ_OBJ) block_decompress.o $(LIB_FUZZING_ENGINE) -o $@
+
+libregression.a: $(FUZZ_HEADERS) $(PRGDIR)/util.h regression_driver.o
+	$(AR) $(FUZZ_ARFLAGS) $@ regression_driver.o
+
+# Install libfuzzer (not usable for MSAN testing)
+# Provided for convienence. To use this library run make libFuzzer and
+# set LDFLAGS=-L.
+.PHONY: libFuzzer
+libFuzzer:
+	@$(RM) -rf Fuzzer
+	@git clone https://chromium.googlesource.com/chromium/llvm-project/llvm/lib/Fuzzer
+	@cd Fuzzer && ./build.sh
+
+corpora/%_seed_corpus.zip:
+	@mkdir -p corpora
+	$(DOWNLOAD) $@ $(CORPORA_URL_PREFIX)$*_seed_corpus.zip
+
+corpora/%: corpora/%_seed_corpus.zip
+	unzip -q $^ -d $@
+
+.PHONY: corpora
+corpora: $(patsubst %,corpora/%,$(FUZZ_TARGETS))
+
+regressiontest: corpora
+	CC="$(CC)" CXX="$(CXX)" CFLAGS="$(CFLAGS)" CXXFLAGS="$(CXXFLAGS)" LDFLAGS="$(LDFLAGS)" $(PYTHON) ./fuzz.py build all
+	$(PYTHON) ./fuzz.py regression all
+
+clean:
+	@$(MAKE) -C $(ZSTDDIR) clean
+	@$(RM) *.a *.o
+	@$(RM) simple_round_trip stream_round_trip simple_decompress \
+           stream_decompress block_decompress block_round_trip
+
+cleanall:
+	@$(RM) -r Fuzzer
+	@$(RM) -r corpora
diff --git a/src/zstd/tests/fuzz/README.md b/src/zstd/tests/fuzz/README.md
new file mode 100644
index 00000000..f184be64
--- /dev/null
+++ b/src/zstd/tests/fuzz/README.md
@@ -0,0 +1,96 @@
+# Fuzzing
+
+Each fuzzing target can be built with multiple engines.
+Zstd provides a fuzz corpus for each target that can be downloaded with
+the command:
+
+```
+make corpora
+```
+
+It will download each corpus into `./corpora/TARGET`.
+
+## fuzz.py
+
+`fuzz.py` is a helper script for building and running fuzzers.
+Run `./fuzz.py -h` for the commands and run `./fuzz.py COMMAND -h` for
+command specific help.
+
+### Generating Data
+
+`fuzz.py` provides a utility to generate seed data for each fuzzer.
+
+```
+make -C ../tests decodecorpus
+./fuzz.py gen TARGET
+```
+
+By default it outputs 100 samples, each at most 8KB into `corpora/TARGET-seed`,
+but that can be configured with the `--number`, `--max-size-log` and `--seed`
+flags.
+
+### Build
+It respects the usual build environment variables `CC`, `CFLAGS`, etc.
+The environment variables can be overridden with the corresponding flags
+`--cc`, `--cflags`, etc.
+The specific fuzzing engine is selected with `LIB_FUZZING_ENGINE` or
+`--lib-fuzzing-engine`, the default is `libregression.a`.
+It has flags that can easily set up sanitizers `--enable-{a,ub,m}san`, and
+coverage instrumentation `--enable-coverage`.
+It sets sane defaults which can be overriden with flags `--debug`,
+`--enable-ubsan-pointer-overlow`, etc.
+Run `./fuzz.py build -h` for help.
+
+### Running Fuzzers
+
+`./fuzz.py` can run `libfuzzer`, `afl`, and `regression` tests.
+See the help of the relevant command for options.
+Flags not parsed by `fuzz.py` are passed to the fuzzing engine.
+The command used to run the fuzzer is printed for debugging.
+
+## LibFuzzer
+
+```
+# Build libfuzzer if necessary
+make libFuzzer
+# Build the fuzz targets
+./fuzz.py build all --enable-coverage --enable-asan --enable-ubsan --lib-fuzzing-engine Fuzzer/libFuzzer.a --cc clang --cxx clang++
+# OR equivalently
+CC=clang CXX=clang++ LIB_FUZZING_ENGINE=Fuzzer/libFuzzer.a ./fuzz.py build all --enable-coverage --enable-asan --enable-ubsan
+# Run the fuzzer
+./fuzz.py libfuzzer TARGET -max_len=8192 -jobs=4
+```
+
+where `TARGET` could be `simple_decompress`, `stream_round_trip`, etc.
+
+### MSAN
+
+Fuzzing with `libFuzzer` and `MSAN` will require building a C++ standard library
+and libFuzzer with MSAN.
+`fuzz.py` respects the environment variables / flags `MSAN_EXTRA_CPPFLAGS`,
+`MSAN_EXTRA_CFLAGS`, `MSAN_EXTRA_CXXFLAGS`, `MSAN_EXTRA_LDFLAGS` to easily pass
+the extra parameters only for MSAN.
+
+## AFL
+
+The default `LIB_FUZZING_ENGINE` is `libregression.a`, which produces a binary
+that AFL can use.
+
+```
+# Build the fuzz targets
+CC=afl-clang CXX=afl-clang++ ./fuzz.py build all --enable-asan --enable-ubsan
+# Run the fuzzer without a memory limit because of ASAN
+./fuzz.py afl TARGET -m none
+```
+
+## Regression Testing
+
+The regression rest supports the `all` target to run all the fuzzers in one
+command.
+
+```
+CC=clang CXX=clang++ ./fuzz.py build all --enable-asan --enable-ubsan
+./fuzz.py regression all
+CC=clang CXX=clang++ ./fuzz.py build all --enable-msan
+./fuzz.py regression all
+```
diff --git a/src/zstd/tests/fuzz/block_decompress.c b/src/zstd/tests/fuzz/block_decompress.c
new file mode 100644
index 00000000..3cccc32f
--- /dev/null
+++ b/src/zstd/tests/fuzz/block_decompress.c
@@ -0,0 +1,51 @@
+/**
+ * Copyright (c) 2016-present, 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).
+ */
+
+/**
+ * This fuzz target attempts to decompress the fuzzed data with the simple
+ * decompression function to ensure the decompressor never crashes.
+ */
+
+#define ZSTD_STATIC_LINKING_ONLY
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include "fuzz_helpers.h"
+#include "zstd.h"
+
+static ZSTD_DCtx *dctx = NULL;
+static void* rBuf = NULL;
+static size_t bufSize = 0;
+
+int LLVMFuzzerTestOneInput(const uint8_t *src, size_t size)
+{
+    size_t const neededBufSize = ZSTD_BLOCKSIZE_MAX;
+
+    FUZZ_seed(&src, &size);
+
+    /* Allocate all buffers and contexts if not already allocated */
+    if (neededBufSize > bufSize) {
+        free(rBuf);
+        rBuf = malloc(neededBufSize);
+        bufSize = neededBufSize;
+        FUZZ_ASSERT(rBuf);
+    }
+    if (!dctx) {
+        dctx = ZSTD_createDCtx();
+        FUZZ_ASSERT(dctx);
+    }
+    ZSTD_decompressBegin(dctx);
+    ZSTD_decompressBlock(dctx, rBuf, neededBufSize, src, size);
+
+#ifndef STATEFUL_FUZZING
+    ZSTD_freeDCtx(dctx); dctx = NULL;
+#endif
+    return 0;
+}
diff --git a/src/zstd/tests/fuzz/block_round_trip.c b/src/zstd/tests/fuzz/block_round_trip.c
new file mode 100644
index 00000000..64ca5fc4
--- /dev/null
+++ b/src/zstd/tests/fuzz/block_round_trip.c
@@ -0,0 +1,92 @@
+/**
+ * Copyright (c) 2016-present, 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).
+ */
+
+/**
+ * This fuzz target performs a zstd round-trip test (compress & decompress),
+ * compares the result with the original, and calls abort() on corruption.
+ */
+
+#define ZSTD_STATIC_LINKING_ONLY
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include "fuzz_helpers.h"
+#include "zstd.h"
+
+static const int kMaxClevel = 19;
+
+static ZSTD_CCtx *cctx = NULL;
+static ZSTD_DCtx *dctx = NULL;
+static void* cBuf = NULL;
+static void* rBuf = NULL;
+static size_t bufSize = 0;
+static uint32_t seed;
+
+static size_t roundTripTest(void *result, size_t resultCapacity,
+                            void *compressed, size_t compressedCapacity,
+                            const void *src, size_t srcSize)
+{
+    int const cLevel = FUZZ_rand(&seed) % kMaxClevel;
+    ZSTD_parameters const params = ZSTD_getParams(cLevel, srcSize, 0);
+    size_t ret = ZSTD_compressBegin_advanced(cctx, NULL, 0, params, srcSize);
+    FUZZ_ZASSERT(ret);
+
+    ret = ZSTD_compressBlock(cctx, compressed, compressedCapacity, src, srcSize);
+    FUZZ_ZASSERT(ret);
+    if (ret == 0) {
+        FUZZ_ASSERT(resultCapacity >= srcSize);
+        memcpy(result, src, srcSize);
+        return srcSize;
+    }
+    ZSTD_decompressBegin(dctx);
+    return ZSTD_decompressBlock(dctx, result, resultCapacity, compressed, ret);
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t *src, size_t size)
+{
+    size_t neededBufSize;
+
+    seed = FUZZ_seed(&src, &size);
+    neededBufSize = size;
+    if (size > ZSTD_BLOCKSIZE_MAX)
+        return 0;
+
+    /* Allocate all buffers and contexts if not already allocated */
+    if (neededBufSize > bufSize || !cBuf || !rBuf) {
+        free(cBuf);
+        free(rBuf);
+        cBuf = malloc(neededBufSize);
+        rBuf = malloc(neededBufSize);
+        bufSize = neededBufSize;
+        FUZZ_ASSERT(cBuf && rBuf);
+    }
+    if (!cctx) {
+        cctx = ZSTD_createCCtx();
+        FUZZ_ASSERT(cctx);
+    }
+    if (!dctx) {
+        dctx = ZSTD_createDCtx();
+        FUZZ_ASSERT(dctx);
+    }
+
+    {
+        size_t const result =
+            roundTripTest(rBuf, neededBufSize, cBuf, neededBufSize, src, size);
+        FUZZ_ZASSERT(result);
+        FUZZ_ASSERT_MSG(result == size, "Incorrect regenerated size");
+        FUZZ_ASSERT_MSG(!memcmp(src, rBuf, size), "Corruption!");
+    }
+#ifndef STATEFUL_FUZZING
+    ZSTD_freeCCtx(cctx); cctx = NULL;
+    ZSTD_freeDCtx(dctx); dctx = NULL;
+#endif
+    return 0;
+}
diff --git a/src/zstd/tests/fuzz/default.options b/src/zstd/tests/fuzz/default.options
new file mode 100644
index 00000000..8ea85883
--- /dev/null
+++ b/src/zstd/tests/fuzz/default.options
@@ -0,0 +1,2 @@
+[libfuzzer]
+max_len = 8192
diff --git a/src/zstd/tests/fuzz/fuzz.h b/src/zstd/tests/fuzz/fuzz.h
new file mode 100644
index 00000000..a6484547
--- /dev/null
+++ b/src/zstd/tests/fuzz/fuzz.h
@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2016-present, 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).
+ */
+
+/**
+ * Fuzz target interface.
+ * Fuzz targets have some common parameters passed as macros during compilation.
+ * Check the documentation for each individual fuzzer for more parameters.
+ *
+ * @param STATEFUL_FUZZING:
+ *        Define this to reuse state between fuzzer runs. This can be useful to
+ *        test code paths which are only executed when contexts are reused.
+ *        WARNING: Makes reproducing crashes much harder.
+ *        Default: Not defined.
+ * @param FUZZ_RNG_SEED_SIZE:
+ *        The number of bytes of the source to look at when constructing a seed
+ *        for the deterministic RNG. These bytes are discarded before passing
+ *        the data to zstd functions. Every fuzzer initializes the RNG exactly
+ *        once before doing anything else, even if it is unused.
+ *        Default: 4.
+ * @param ZSTD_DEBUG:
+ *        This is a parameter for the zstd library. Defining `ZSTD_DEBUG=1`
+ *        enables assert() statements in the zstd library. Higher levels enable
+ *        logging, so aren't recommended. Defining `ZSTD_DEBUG=1` is
+ *        recommended.
+ * @param MEM_FORCE_MEMORY_ACCESS:
+ *        This flag controls how the zstd library accesses unaligned memory.
+ *        It can be undefined, or 0 through 2. If it is undefined, it selects
+ *        the method to use based on the compiler. If testing with UBSAN set
+ *        MEM_FORCE_MEMORY_ACCESS=0 to use the standard compliant method.
+ * @param FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
+ *        This is the canonical flag to enable deterministic builds for fuzzing.
+ *        Changes to zstd for fuzzing are gated behind this define.
+ *        It is recommended to define this when building zstd for fuzzing.
+ */
+
+#ifndef FUZZ_H
+#define FUZZ_H
+
+#ifndef FUZZ_RNG_SEED_SIZE
+#  define FUZZ_RNG_SEED_SIZE 4
+#endif
+
+#include <stddef.h>
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int LLVMFuzzerTestOneInput(const uint8_t *src, size_t size);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/src/zstd/tests/fuzz/fuzz.py b/src/zstd/tests/fuzz/fuzz.py
new file mode 100755
index 00000000..b591e4f6
--- /dev/null
+++ b/src/zstd/tests/fuzz/fuzz.py
@@ -0,0 +1,818 @@
+#!/usr/bin/env python
+
+# ################################################################
+# Copyright (c) 2016-present, 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).
+# ##########################################################################
+
+import argparse
+import contextlib
+import os
+import re
+import shutil
+import subprocess
+import sys
+import tempfile
+
+
+def abs_join(a, *p):
+    return os.path.abspath(os.path.join(a, *p))
+
+
+# Constants
+FUZZ_DIR = os.path.abspath(os.path.dirname(__file__))
+CORPORA_DIR = abs_join(FUZZ_DIR, 'corpora')
+TARGETS = [
+    'simple_round_trip',
+    'stream_round_trip',
+    'block_round_trip',
+    'simple_decompress',
+    'stream_decompress',
+    'block_decompress',
+]
+ALL_TARGETS = TARGETS + ['all']
+FUZZ_RNG_SEED_SIZE = 4
+
+# Standard environment variables
+CC = os.environ.get('CC', 'cc')
+CXX = os.environ.get('CXX', 'c++')
+CPPFLAGS = os.environ.get('CPPFLAGS', '')
+CFLAGS = os.environ.get('CFLAGS', '-O3')
+CXXFLAGS = os.environ.get('CXXFLAGS', CFLAGS)
+LDFLAGS = os.environ.get('LDFLAGS', '')
+MFLAGS = os.environ.get('MFLAGS', '-j')
+
+# Fuzzing environment variables
+LIB_FUZZING_ENGINE = os.environ.get('LIB_FUZZING_ENGINE', 'libregression.a')
+AFL_FUZZ = os.environ.get('AFL_FUZZ', 'afl-fuzz')
+DECODECORPUS = os.environ.get('DECODECORPUS',
+                              abs_join(FUZZ_DIR, '..', 'decodecorpus'))
+
+# Sanitizer environment variables
+MSAN_EXTRA_CPPFLAGS = os.environ.get('MSAN_EXTRA_CPPFLAGS', '')
+MSAN_EXTRA_CFLAGS = os.environ.get('MSAN_EXTRA_CFLAGS', '')
+MSAN_EXTRA_CXXFLAGS = os.environ.get('MSAN_EXTRA_CXXFLAGS', '')
+MSAN_EXTRA_LDFLAGS = os.environ.get('MSAN_EXTRA_LDFLAGS', '')
+
+
+def create(r):
+    d = os.path.abspath(r)
+    if not os.path.isdir(d):
+        os.mkdir(d)
+    return d
+
+
+def check(r):
+    d = os.path.abspath(r)
+    if not os.path.isdir(d):
+        return None
+    return d
+
+
+@contextlib.contextmanager
+def tmpdir():
+    dirpath = tempfile.mkdtemp()
+    try:
+        yield dirpath
+    finally:
+        shutil.rmtree(dirpath, ignore_errors=True)
+
+
+def parse_targets(in_targets):
+    targets = set()
+    for target in in_targets:
+        if not target:
+            continue
+        if target == 'all':
+            targets = targets.union(TARGETS)
+        elif target in TARGETS:
+            targets.add(target)
+        else:
+            raise RuntimeError('{} is not a valid target'.format(target))
+    return list(targets)
+
+
+def targets_parser(args, description):
+    parser = argparse.ArgumentParser(prog=args.pop(0), description=description)
+    parser.add_argument(
+        'TARGET',
+        nargs='*',
+        type=str,
+        help='Fuzz target(s) to build {{{}}}'.format(', '.join(ALL_TARGETS)))
+    args, extra = parser.parse_known_args(args)
+    args.extra = extra
+
+    args.TARGET = parse_targets(args.TARGET)
+
+    return args
+
+
+def parse_env_flags(args, flags):
+    """
+    Look for flags set by environment variables.
+    """
+    san_flags = ','.join(re.findall('-fsanitize=((?:[a-z]+,?)+)', flags))
+    nosan_flags = ','.join(re.findall('-fno-sanitize=((?:[a-z]+,?)+)', flags))
+
+    def set_sanitizer(sanitizer, default, san, nosan):
+        if sanitizer in san and sanitizer in nosan:
+            raise RuntimeError('-fno-sanitize={s} and -fsanitize={s} passed'.
+                               format(s=sanitizer))
+        if sanitizer in san:
+            return True
+        if sanitizer in nosan:
+            return False
+        return default
+
+    san = set(san_flags.split(','))
+    nosan = set(nosan_flags.split(','))
+
+    args.asan = set_sanitizer('address', args.asan, san, nosan)
+    args.msan = set_sanitizer('memory', args.msan, san, nosan)
+    args.ubsan = set_sanitizer('undefined', args.ubsan, san, nosan)
+
+    args.sanitize = args.asan or args.msan or args.ubsan
+
+    return args
+
+
+def compiler_version(cc, cxx):
+    """
+    Determines the compiler and version.
+    Only works for clang and gcc.
+    """
+    cc_version_bytes = subprocess.check_output([cc, "--version"])
+    cxx_version_bytes = subprocess.check_output([cxx, "--version"])
+    if cc_version_bytes.startswith(b'clang'):
+        assert(cxx_version_bytes.startswith(b'clang'))
+        compiler = 'clang'
+    if cc_version_bytes.startswith(b'gcc'):
+        assert(cxx_version_bytes.startswith(b'g++'))
+        compiler = 'gcc'
+    version_regex = b'([0-9])+\.([0-9])+\.([0-9])+'
+    version_match = re.search(version_regex, cc_version_bytes)
+    version = tuple(int(version_match.group(i)) for i in range(1, 4))
+    return compiler, version
+
+
+def overflow_ubsan_flags(cc, cxx):
+    compiler, version = compiler_version(cc, cxx)
+    if compiler == 'gcc':
+        return ['-fno-sanitize=signed-integer-overflow']
+    if compiler == 'clang' and version >= (5, 0, 0):
+        return ['-fno-sanitize=pointer-overflow']
+    return []
+
+
+def build_parser(args):
+    description = """
+    Cleans the repository and builds a fuzz target (or all).
+    Many flags default to environment variables (default says $X='y').
+    Options that aren't enabling features default to the correct values for
+    zstd.
+    Enable sanitizers with --enable-*san.
+    For regression testing just build.
+    For libFuzzer set LIB_FUZZING_ENGINE and pass --enable-coverage.
+    For AFL set CC and CXX to AFL's compilers and set
+    LIB_FUZZING_ENGINE='libregression.a'.
+    """
+    parser = argparse.ArgumentParser(prog=args.pop(0), description=description)
+    parser.add_argument(
+        '--lib-fuzzing-engine',
+        dest='lib_fuzzing_engine',
+        type=str,
+        default=LIB_FUZZING_ENGINE,
+        help=('The fuzzing engine to use e.g. /path/to/libFuzzer.a '
+              "(default: $LIB_FUZZING_ENGINE='{})".format(LIB_FUZZING_ENGINE)))
+    parser.add_argument(
+        '--enable-coverage',
+        dest='coverage',
+        action='store_true',
+        help='Enable coverage instrumentation (-fsanitize-coverage)')
+    parser.add_argument(
+        '--enable-asan', dest='asan', action='store_true', help='Enable UBSAN')
+    parser.add_argument(
+        '--enable-ubsan',
+        dest='ubsan',
+        action='store_true',
+        help='Enable UBSAN')
+    parser.add_argument(
+        '--enable-ubsan-pointer-overflow',
+        dest='ubsan_pointer_overflow',
+        action='store_true',
+        help='Enable UBSAN pointer overflow check (known failure)')
+    parser.add_argument(
+        '--enable-msan', dest='msan', action='store_true', help='Enable MSAN')
+    parser.add_argument(
+        '--enable-msan-track-origins', dest='msan_track_origins',
+        action='store_true', help='Enable MSAN origin tracking')
+    parser.add_argument(
+        '--msan-extra-cppflags',
+        dest='msan_extra_cppflags',
+        type=str,
+        default=MSAN_EXTRA_CPPFLAGS,
+        help="Extra CPPFLAGS for MSAN (default: $MSAN_EXTRA_CPPFLAGS='{}')".
+        format(MSAN_EXTRA_CPPFLAGS))
+    parser.add_argument(
+        '--msan-extra-cflags',
+        dest='msan_extra_cflags',
+        type=str,
+        default=MSAN_EXTRA_CFLAGS,
+        help="Extra CFLAGS for MSAN (default: $MSAN_EXTRA_CFLAGS='{}')".format(
+            MSAN_EXTRA_CFLAGS))
+    parser.add_argument(
+        '--msan-extra-cxxflags',
+        dest='msan_extra_cxxflags',
+        type=str,
+        default=MSAN_EXTRA_CXXFLAGS,
+        help="Extra CXXFLAGS for MSAN (default: $MSAN_EXTRA_CXXFLAGS='{}')".
+        format(MSAN_EXTRA_CXXFLAGS))
+    parser.add_argument(
+        '--msan-extra-ldflags',
+        dest='msan_extra_ldflags',
+        type=str,
+        default=MSAN_EXTRA_LDFLAGS,
+        help="Extra LDFLAGS for MSAN (default: $MSAN_EXTRA_LDFLAGS='{}')".
+        format(MSAN_EXTRA_LDFLAGS))
+    parser.add_argument(
+        '--enable-sanitize-recover',
+        dest='sanitize_recover',
+        action='store_true',
+        help='Non-fatal sanitizer errors where possible')
+    parser.add_argument(
+        '--debug',
+        dest='debug',
+        type=int,
+        default=1,
+        help='Set ZSTD_DEBUG (default: 1)')
+    parser.add_argument(
+        '--force-memory-access',
+        dest='memory_access',
+        type=int,
+        default=0,
+        help='Set MEM_FORCE_MEMORY_ACCESS (default: 0)')
+    parser.add_argument(
+        '--fuzz-rng-seed-size',
+        dest='fuzz_rng_seed_size',
+        type=int,
+        default=4,
+        help='Set FUZZ_RNG_SEED_SIZE (default: 4)')
+    parser.add_argument(
+        '--disable-fuzzing-mode',
+        dest='fuzzing_mode',
+        action='store_false',
+        help='Do not define FUZZING_BUILD_MORE_UNSAFE_FOR_PRODUCTION')
+    parser.add_argument(
+        '--enable-stateful-fuzzing',
+        dest='stateful_fuzzing',
+        action='store_true',
+        help='Reuse contexts between runs (makes reproduction impossible)')
+    parser.add_argument(
+        '--cc',
+        dest='cc',
+        type=str,
+        default=CC,
+        help="CC (default: $CC='{}')".format(CC))
+    parser.add_argument(
+        '--cxx',
+        dest='cxx',
+        type=str,
+        default=CXX,
+        help="CXX (default: $CXX='{}')".format(CXX))
+    parser.add_argument(
+        '--cppflags',
+        dest='cppflags',
+        type=str,
+        default=CPPFLAGS,
+        help="CPPFLAGS (default: $CPPFLAGS='{}')".format(CPPFLAGS))
+    parser.add_argument(
+        '--cflags',
+        dest='cflags',
+        type=str,
+        default=CFLAGS,
+        help="CFLAGS (default: $CFLAGS='{}')".format(CFLAGS))
+    parser.add_argument(
+        '--cxxflags',
+        dest='cxxflags',
+        type=str,
+        default=CXXFLAGS,
+        help="CXXFLAGS (default: $CXXFLAGS='{}')".format(CXXFLAGS))
+    parser.add_argument(
+        '--ldflags',
+        dest='ldflags',
+        type=str,
+        default=LDFLAGS,
+        help="LDFLAGS (default: $LDFLAGS='{}')".format(LDFLAGS))
+    parser.add_argument(
+        '--mflags',
+        dest='mflags',
+        type=str,
+        default=MFLAGS,
+        help="Extra Make flags (default: $MFLAGS='{}')".format(MFLAGS))
+    parser.add_argument(
+        'TARGET',
+        nargs='*',
+        type=str,
+        help='Fuzz target(s) to build {{{}}}'.format(', '.join(ALL_TARGETS))
+    )
+    args = parser.parse_args(args)
+    args = parse_env_flags(args, ' '.join(
+        [args.cppflags, args.cflags, args.cxxflags, args.ldflags]))
+
+    # Check option sanitiy
+    if args.msan and (args.asan or args.ubsan):
+        raise RuntimeError('MSAN may not be used with any other sanitizers')
+    if args.msan_track_origins and not args.msan:
+        raise RuntimeError('--enable-msan-track-origins requires MSAN')
+    if args.ubsan_pointer_overflow and not args.ubsan:
+        raise RuntimeError('--enable-ubsan-pointer-overlow requires UBSAN')
+    if args.sanitize_recover and not args.sanitize:
+        raise RuntimeError('--enable-sanitize-recover but no sanitizers used')
+
+    return args
+
+
+def build(args):
+    try:
+        args = build_parser(args)
+    except Exception as e:
+        print(e)
+        return 1
+    # The compilation flags we are setting
+    targets = args.TARGET
+    cc = args.cc
+    cxx = args.cxx
+    cppflags = [args.cppflags]
+    cflags = [args.cflags]
+    ldflags = [args.ldflags]
+    cxxflags = [args.cxxflags]
+    mflags = [args.mflags] if args.mflags else []
+    # Flags to be added to both cflags and cxxflags
+    common_flags = []
+
+    cppflags += [
+        '-DZSTD_DEBUG={}'.format(args.debug),
+        '-DMEM_FORCE_MEMORY_ACCESS={}'.format(args.memory_access),
+        '-DFUZZ_RNG_SEED_SIZE={}'.format(args.fuzz_rng_seed_size),
+    ]
+
+    mflags += ['LIB_FUZZING_ENGINE={}'.format(args.lib_fuzzing_engine)]
+
+    # Set flags for options
+    if args.coverage:
+        common_flags += [
+            '-fsanitize-coverage=trace-pc-guard,indirect-calls,trace-cmp'
+        ]
+
+    if args.sanitize_recover:
+        recover_flags = ['-fsanitize-recover=all']
+    else:
+        recover_flags = ['-fno-sanitize-recover=all']
+    if args.sanitize:
+        common_flags += recover_flags
+
+    if args.msan:
+        msan_flags = ['-fsanitize=memory']
+        if args.msan_track_origins:
+            msan_flags += ['-fsanitize-memory-track-origins']
+        common_flags += msan_flags
+        # Append extra MSAN flags (it might require special setup)
+        cppflags += [args.msan_extra_cppflags]
+        cflags += [args.msan_extra_cflags]
+        cxxflags += [args.msan_extra_cxxflags]
+        ldflags += [args.msan_extra_ldflags]
+
+    if args.asan:
+        common_flags += ['-fsanitize=address']
+
+    if args.ubsan:
+        ubsan_flags = ['-fsanitize=undefined']
+        if not args.ubsan_pointer_overflow:
+            ubsan_flags += overflow_ubsan_flags(cc, cxx)
+        common_flags += ubsan_flags
+
+    if args.stateful_fuzzing:
+        cppflags += ['-DSTATEFUL_FUZZING']
+
+    if args.fuzzing_mode:
+        cppflags += ['-DFUZZING_BUILD_MORE_UNSAFE_FOR_PRODUCTION']
+
+    if args.lib_fuzzing_engine == 'libregression.a':
+        targets = ['libregression.a'] + targets
+
+    # Append the common flags
+    cflags += common_flags
+    cxxflags += common_flags
+
+    # Prepare the flags for Make
+    cc_str = "CC={}".format(cc)
+    cxx_str = "CXX={}".format(cxx)
+    cppflags_str = "CPPFLAGS={}".format(' '.join(cppflags))
+    cflags_str = "CFLAGS={}".format(' '.join(cflags))
+    cxxflags_str = "CXXFLAGS={}".format(' '.join(cxxflags))
+    ldflags_str = "LDFLAGS={}".format(' '.join(ldflags))
+
+    # Print the flags
+    print('MFLAGS={}'.format(' '.join(mflags)))
+    print(cc_str)
+    print(cxx_str)
+    print(cppflags_str)
+    print(cflags_str)
+    print(cxxflags_str)
+    print(ldflags_str)
+
+    # Clean and build
+    clean_cmd = ['make', 'clean'] + mflags
+    print(' '.join(clean_cmd))
+    subprocess.check_call(clean_cmd)
+    build_cmd = [
+        'make',
+        cc_str,
+        cxx_str,
+        cppflags_str,
+        cflags_str,
+        cxxflags_str,
+        ldflags_str,
+    ] + mflags + targets
+    print(' '.join(build_cmd))
+    subprocess.check_call(build_cmd)
+    return 0
+
+
+def libfuzzer_parser(args):
+    description = """
+    Runs a libfuzzer binary.
+    Passes all extra arguments to libfuzzer.
+    The fuzzer should have been build with LIB_FUZZING_ENGINE pointing to
+    libFuzzer.a.
+    Generates output in the CORPORA directory, puts crashes in the ARTIFACT
+    directory, and takes extra input from the SEED directory.
+    To merge AFL's output pass the SEED as AFL's output directory and pass
+    '-merge=1'.
+    """
+    parser = argparse.ArgumentParser(prog=args.pop(0), description=description)
+    parser.add_argument(
+        '--corpora',
+        type=str,
+        help='Override the default corpora dir (default: {})'.format(
+            abs_join(CORPORA_DIR, 'TARGET')))
+    parser.add_argument(
+        '--artifact',
+        type=str,
+        help='Override the default artifact dir (default: {})'.format(
+            abs_join(CORPORA_DIR, 'TARGET-crash')))
+    parser.add_argument(
+        '--seed',
+        type=str,
+        help='Override the default seed dir (default: {})'.format(
+            abs_join(CORPORA_DIR, 'TARGET-seed')))
+    parser.add_argument(
+        'TARGET',
+        type=str,
+        help='Fuzz target(s) to build {{{}}}'.format(', '.join(TARGETS)))
+    args, extra = parser.parse_known_args(args)
+    args.extra = extra
+
+    if args.TARGET and args.TARGET not in TARGETS:
+        raise RuntimeError('{} is not a valid target'.format(args.TARGET))
+
+    return args
+
+
+def libfuzzer(target, corpora=None, artifact=None, seed=None, extra_args=None):
+    if corpora is None:
+        corpora = abs_join(CORPORA_DIR, target)
+    if artifact is None:
+        artifact = abs_join(CORPORA_DIR, '{}-crash'.format(target))
+    if seed is None:
+        seed = abs_join(CORPORA_DIR, '{}-seed'.format(target))
+    if extra_args is None:
+        extra_args = []
+
+    target = abs_join(FUZZ_DIR, target)
+
+    corpora = [create(corpora)]
+    artifact = create(artifact)
+    seed = check(seed)
+
+    corpora += [artifact]
+    if seed is not None:
+        corpora += [seed]
+
+    cmd = [target, '-artifact_prefix={}/'.format(artifact)]
+    cmd += corpora + extra_args
+    print(' '.join(cmd))
+    subprocess.check_call(cmd)
+
+
+def libfuzzer_cmd(args):
+    try:
+        args = libfuzzer_parser(args)
+    except Exception as e:
+        print(e)
+        return 1
+    libfuzzer(args.TARGET, args.corpora, args.artifact, args.seed, args.extra)
+    return 0
+
+
+def afl_parser(args):
+    description = """
+    Runs an afl-fuzz job.
+    Passes all extra arguments to afl-fuzz.
+    The fuzzer should have been built with CC/CXX set to the AFL compilers,
+    and with LIB_FUZZING_ENGINE='libregression.a'.
+    Takes input from CORPORA and writes output to OUTPUT.
+    Uses AFL_FUZZ as the binary (set from flag or environment variable).
+    """
+    parser = argparse.ArgumentParser(prog=args.pop(0), description=description)
+    parser.add_argument(
+        '--corpora',
+        type=str,
+        help='Override the default corpora dir (default: {})'.format(
+            abs_join(CORPORA_DIR, 'TARGET')))
+    parser.add_argument(
+        '--output',
+        type=str,
+        help='Override the default AFL output dir (default: {})'.format(
+            abs_join(CORPORA_DIR, 'TARGET-afl')))
+    parser.add_argument(
+        '--afl-fuzz',
+        type=str,
+        default=AFL_FUZZ,
+        help='AFL_FUZZ (default: $AFL_FUZZ={})'.format(AFL_FUZZ))
+    parser.add_argument(
+        'TARGET',
+        type=str,
+        help='Fuzz target(s) to build {{{}}}'.format(', '.join(TARGETS)))
+    args, extra = parser.parse_known_args(args)
+    args.extra = extra
+
+    if args.TARGET and args.TARGET not in TARGETS:
+        raise RuntimeError('{} is not a valid target'.format(args.TARGET))
+
+    if not args.corpora:
+        args.corpora = abs_join(CORPORA_DIR, args.TARGET)
+    if not args.output:
+        args.output = abs_join(CORPORA_DIR, '{}-afl'.format(args.TARGET))
+
+    return args
+
+
+def afl(args):
+    try:
+        args = afl_parser(args)
+    except Exception as e:
+        print(e)
+        return 1
+    target = abs_join(FUZZ_DIR, args.TARGET)
+
+    corpora = create(args.corpora)
+    output = create(args.output)
+
+    cmd = [args.afl_fuzz, '-i', corpora, '-o', output] + args.extra
+    cmd += [target, '@@']
+    print(' '.join(cmd))
+    subprocess.call(cmd)
+    return 0
+
+
+def regression(args):
+    try:
+        description = """
+        Runs one or more regression tests.
+        The fuzzer should have been built with with
+        LIB_FUZZING_ENGINE='libregression.a'.
+        Takes input from CORPORA.
+        """
+        args = targets_parser(args, description)
+    except Exception as e:
+        print(e)
+        return 1
+    for target in args.TARGET:
+        corpora = create(abs_join(CORPORA_DIR, target))
+        target = abs_join(FUZZ_DIR, target)
+        cmd = [target, corpora]
+        print(' '.join(cmd))
+        subprocess.check_call(cmd)
+    return 0
+
+
+def gen_parser(args):
+    description = """
+    Generate a seed corpus appropiate for TARGET with data generated with
+    decodecorpus.
+    The fuzz inputs are prepended with a seed before the zstd data, so the
+    output of decodecorpus shouldn't be used directly.
+    Generates NUMBER samples prepended with FUZZ_RNG_SEED_SIZE random bytes and
+    puts the output in SEED.
+    DECODECORPUS is the decodecorpus binary, and must already be built.
+    """
+    parser = argparse.ArgumentParser(prog=args.pop(0), description=description)
+    parser.add_argument(
+        '--number',
+        '-n',
+        type=int,
+        default=100,
+        help='Number of samples to generate')
+    parser.add_argument(
+        '--max-size-log',
+        type=int,
+        default=13,
+        help='Maximum sample size to generate')
+    parser.add_argument(
+        '--seed',
+        type=str,
+        help='Override the default seed dir (default: {})'.format(
+            abs_join(CORPORA_DIR, 'TARGET-seed')))
+    parser.add_argument(
+        '--decodecorpus',
+        type=str,
+        default=DECODECORPUS,
+        help="decodecorpus binary (default: $DECODECORPUS='{}')".format(
+            DECODECORPUS))
+    parser.add_argument(
+        '--fuzz-rng-seed-size',
+        type=int,
+        default=4,
+        help="FUZZ_RNG_SEED_SIZE used for generate the samples (must match)"
+    )
+    parser.add_argument(
+        'TARGET',
+        type=str,
+        help='Fuzz target(s) to build {{{}}}'.format(', '.join(TARGETS)))
+    args, extra = parser.parse_known_args(args)
+    args.extra = extra
+
+    if args.TARGET and args.TARGET not in TARGETS:
+        raise RuntimeError('{} is not a valid target'.format(args.TARGET))
+
+    if not args.seed:
+        args.seed = abs_join(CORPORA_DIR, '{}-seed'.format(args.TARGET))
+
+    if not os.path.isfile(args.decodecorpus):
+        raise RuntimeError("{} is not a file run 'make -C {} decodecorpus'".
+                           format(args.decodecorpus, abs_join(FUZZ_DIR, '..')))
+
+    return args
+
+
+def gen(args):
+    try:
+        args = gen_parser(args)
+    except Exception as e:
+        print(e)
+        return 1
+
+    seed = create(args.seed)
+    with tmpdir() as compressed:
+        with tmpdir() as decompressed:
+            cmd = [
+                args.decodecorpus,
+                '-n{}'.format(args.number),
+                '-p{}/'.format(compressed),
+                '-o{}'.format(decompressed),
+            ]
+
+            if 'block_' in args.TARGET:
+                cmd += [
+                    '--gen-blocks',
+                    '--max-block-size-log={}'.format(args.max_size_log)
+                ]
+            else:
+                cmd += ['--max-content-size-log={}'.format(args.max_size_log)]
+
+            print(' '.join(cmd))
+            subprocess.check_call(cmd)
+
+            if '_round_trip' in args.TARGET:
+                print('using decompressed data in {}'.format(decompressed))
+                samples = decompressed
+            elif '_decompress' in args.TARGET:
+                print('using compressed data in {}'.format(compressed))
+                samples = compressed
+
+            # Copy the samples over and prepend the RNG seeds
+            for name in os.listdir(samples):
+                samplename = abs_join(samples, name)
+                outname = abs_join(seed, name)
+                rng_seed = os.urandom(args.fuzz_rng_seed_size)
+                with open(samplename, 'rb') as sample:
+                    with open(outname, 'wb') as out:
+                        out.write(rng_seed)
+                        CHUNK_SIZE = 131072
+                        chunk = sample.read(CHUNK_SIZE)
+                        while len(chunk) > 0:
+                            out.write(chunk)
+                            chunk = sample.read(CHUNK_SIZE)
+    return 0
+
+
+def minimize(args):
+    try:
+        description = """
+        Runs a libfuzzer fuzzer with -merge=1 to build a minimal corpus in
+        TARGET_seed_corpus. All extra args are passed to libfuzzer.
+        """
+        args = targets_parser(args, description)
+    except Exception as e:
+        print(e)
+        return 1
+
+    for target in args.TARGET:
+        # Merge the corpus + anything else into the seed_corpus
+        corpus = abs_join(CORPORA_DIR, target)
+        seed_corpus = abs_join(CORPORA_DIR, "{}_seed_corpus".format(target))
+        extra_args = [corpus, "-merge=1"] + args.extra
+        libfuzzer(target, corpora=seed_corpus, extra_args=extra_args)
+        seeds = set(os.listdir(seed_corpus))
+        # Copy all crashes directly into the seed_corpus if not already present
+        crashes = abs_join(CORPORA_DIR, '{}-crash'.format(target))
+        for crash in os.listdir(crashes):
+            if crash not in seeds:
+                shutil.copy(abs_join(crashes, crash), seed_corpus)
+                seeds.add(crash)
+
+
+def zip_cmd(args):
+    try:
+        description = """
+        Zips up the seed corpus.
+        """
+        args = targets_parser(args, description)
+    except Exception as e:
+        print(e)
+        return 1
+
+    for target in args.TARGET:
+        # Zip the seed_corpus
+        seed_corpus = abs_join(CORPORA_DIR, "{}_seed_corpus".format(target))
+        seeds = [abs_join(seed_corpus, f) for f in os.listdir(seed_corpus)]
+        zip_file = "{}.zip".format(seed_corpus)
+        cmd = ["zip", "-q", "-j", "-9", zip_file]
+        print(' '.join(cmd + [abs_join(seed_corpus, '*')]))
+        subprocess.check_call(cmd + seeds)
+
+
+def list_cmd(args):
+    print("\n".join(TARGETS))
+
+
+def short_help(args):
+    name = args[0]
+    print("Usage: {} [OPTIONS] COMMAND [ARGS]...\n".format(name))
+
+
+def help(args):
+    short_help(args)
+    print("\tfuzzing helpers (select a command and pass -h for help)\n")
+    print("Options:")
+    print("\t-h, --help\tPrint this message")
+    print("")
+    print("Commands:")
+    print("\tbuild\t\tBuild a fuzzer")
+    print("\tlibfuzzer\tRun a libFuzzer fuzzer")
+    print("\tafl\t\tRun an AFL fuzzer")
+    print("\tregression\tRun a regression test")
+    print("\tgen\t\tGenerate a seed corpus for a fuzzer")
+    print("\tminimize\tMinimize the test corpora")
+    print("\tzip\t\tZip the minimized corpora up")
+    print("\tlist\t\tList the available targets")
+
+
+def main():
+    args = sys.argv
+    if len(args) < 2:
+        help(args)
+        return 1
+    if args[1] == '-h' or args[1] == '--help' or args[1] == '-H':
+        help(args)
+        return 1
+    command = args.pop(1)
+    args[0] = "{} {}".format(args[0], command)
+    if command == "build":
+        return build(args)
+    if command == "libfuzzer":
+        return libfuzzer_cmd(args)
+    if command == "regression":
+        return regression(args)
+    if command == "afl":
+        return afl(args)
+    if command == "gen":
+        return gen(args)
+    if command == "minimize":
+        return minimize(args)
+    if command == "zip":
+        return zip_cmd(args)
+    if command == "list":
+        return list_cmd(args)
+    short_help(args)
+    print("Error: No such command {} (pass -h for help)".format(command))
+    return 1
+
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/src/zstd/tests/fuzz/fuzz_helpers.h b/src/zstd/tests/fuzz/fuzz_helpers.h
new file mode 100644
index 00000000..468c39fb
--- /dev/null
+++ b/src/zstd/tests/fuzz/fuzz_helpers.h
@@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2016-present, 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).
+ */
+
+/**
+ * Helper functions for fuzzing.
+ */
+
+#ifndef FUZZ_HELPERS_H
+#define FUZZ_HELPERS_H
+
+#include "fuzz.h"
+#include "xxhash.h"
+#include "zstd.h"
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+
+#define FUZZ_QUOTE_IMPL(str) #str
+#define FUZZ_QUOTE(str) FUZZ_QUOTE_IMPL(str)
+
+/**
+ * Asserts for fuzzing that are always enabled.
+ */
+#define FUZZ_ASSERT_MSG(cond, msg)                                             \
+  ((cond) ? (void)0                                                            \
+          : (fprintf(stderr, "%s: %u: Assertion: `%s' failed. %s\n", __FILE__, \
+                     __LINE__, FUZZ_QUOTE(cond), (msg)),                       \
+             abort()))
+#define FUZZ_ASSERT(cond) FUZZ_ASSERT_MSG((cond), "");
+#define FUZZ_ZASSERT(code)                                                     \
+  FUZZ_ASSERT_MSG(!ZSTD_isError(code), ZSTD_getErrorName(code))
+
+#if defined(__GNUC__)
+#define FUZZ_STATIC static __inline __attribute__((unused))
+#elif defined(__cplusplus) ||                                                  \
+    (defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
+#define FUZZ_STATIC static inline
+#elif defined(_MSC_VER)
+#define FUZZ_STATIC static __inline
+#else
+#define FUZZ_STATIC static
+#endif
+
+/**
+ * Determininistically constructs a seed based on the fuzz input.
+ * Consumes up to the first FUZZ_RNG_SEED_SIZE bytes of the input.
+ */
+FUZZ_STATIC uint32_t FUZZ_seed(uint8_t const **src, size_t* size) {
+    uint8_t const *data = *src;
+    size_t const toHash = MIN(FUZZ_RNG_SEED_SIZE, *size);
+    *size -= toHash;
+    *src += toHash;
+    return XXH32(data, toHash, 0);
+}
+
+#define FUZZ_rotl32(x, r) (((x) << (r)) | ((x) >> (32 - (r))))
+
+FUZZ_STATIC uint32_t FUZZ_rand(uint32_t *state) {
+    static const uint32_t prime1 = 2654435761U;
+    static const uint32_t prime2 = 2246822519U;
+    uint32_t rand32 = *state;
+    rand32 *= prime1;
+    rand32 += prime2;
+    rand32 = FUZZ_rotl32(rand32, 13);
+    *state = rand32;
+    return rand32 >> 5;
+}
+
+/* Returns a random numer in the range [min, max]. */
+FUZZ_STATIC uint32_t FUZZ_rand32(uint32_t *state, uint32_t min, uint32_t max) {
+    uint32_t random = FUZZ_rand(state);
+    return min + (random % (max - min + 1));
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/src/zstd/tests/fuzz/regression_driver.c b/src/zstd/tests/fuzz/regression_driver.c
new file mode 100644
index 00000000..2b714d29
--- /dev/null
+++ b/src/zstd/tests/fuzz/regression_driver.c
@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2016-present, 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).
+ */
+
+#include "fuzz.h"
+#include "fuzz_helpers.h"
+#include "util.h"
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int argc, char const **argv) {
+  size_t const kMaxFileSize = (size_t)1 << 20;
+  int const kFollowLinks = 1;
+  char *fileNamesBuf = NULL;
+  char const **files = argv + 1;
+  unsigned numFiles = argc - 1;
+  uint8_t *buffer = NULL;
+  size_t bufferSize = 0;
+  unsigned i;
+  int ret;
+
+#ifdef UTIL_HAS_CREATEFILELIST
+  files = UTIL_createFileList(files, numFiles, &fileNamesBuf, &numFiles,
+                              kFollowLinks);
+  if (!files)
+    numFiles = 0;
+#endif
+  if (numFiles == 0)
+    fprintf(stderr, "WARNING: No files passed to %s\n", argv[0]);
+  for (i = 0; i < numFiles; ++i) {
+    char const *fileName = files[i];
+    size_t const fileSize = UTIL_getFileSize(fileName);
+    size_t readSize;
+    FILE *file;
+
+    /* Check that it is a regular file, and that the fileSize is valid */
+    FUZZ_ASSERT_MSG(UTIL_isRegularFile(fileName), fileName);
+    FUZZ_ASSERT_MSG(fileSize <= kMaxFileSize, fileName);
+    /* Ensure we have a large enough buffer allocated */
+    if (fileSize > bufferSize) {
+      free(buffer);
+      buffer = (uint8_t *)malloc(fileSize);
+      FUZZ_ASSERT_MSG(buffer, fileName);
+      bufferSize = fileSize;
+    }
+    /* Open the file */
+    file = fopen(fileName, "rb");
+    FUZZ_ASSERT_MSG(file, fileName);
+    /* Read the file */
+    readSize = fread(buffer, 1, fileSize, file);
+    FUZZ_ASSERT_MSG(readSize == fileSize, fileName);
+    /* Close the file */
+    fclose(file);
+    /* Run the fuzz target */
+    LLVMFuzzerTestOneInput(buffer, fileSize);
+  }
+
+  ret = 0;
+  free(buffer);
+#ifdef UTIL_HAS_CREATEFILELIST
+  UTIL_freeFileList(files, fileNamesBuf);
+#endif
+  return ret;
+}
diff --git a/src/zstd/tests/fuzz/simple_decompress.c b/src/zstd/tests/fuzz/simple_decompress.c
new file mode 100644
index 00000000..bba272c6
--- /dev/null
+++ b/src/zstd/tests/fuzz/simple_decompress.c
@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2016-present, 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).
+ */
+
+/**
+ * This fuzz target attempts to decompress the fuzzed data with the simple
+ * decompression function to ensure the decompressor never crashes.
+ */
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include "fuzz_helpers.h"
+#include "zstd.h"
+
+static ZSTD_DCtx *dctx = NULL;
+static void* rBuf = NULL;
+static size_t bufSize = 0;
+
+int LLVMFuzzerTestOneInput(const uint8_t *src, size_t size)
+{
+    size_t neededBufSize;
+
+    FUZZ_seed(&src, &size);
+    neededBufSize = MAX(20 * size, (size_t)256 << 10);
+
+    /* Allocate all buffers and contexts if not already allocated */
+    if (neededBufSize > bufSize) {
+        free(rBuf);
+        rBuf = malloc(neededBufSize);
+        bufSize = neededBufSize;
+        FUZZ_ASSERT(rBuf);
+    }
+    if (!dctx) {
+        dctx = ZSTD_createDCtx();
+        FUZZ_ASSERT(dctx);
+    }
+    ZSTD_decompressDCtx(dctx, rBuf, neededBufSize, src, size);
+
+#ifndef STATEFUL_FUZZING
+    ZSTD_freeDCtx(dctx); dctx = NULL;
+#endif
+    return 0;
+}
diff --git a/src/zstd/tests/fuzz/simple_round_trip.c b/src/zstd/tests/fuzz/simple_round_trip.c
new file mode 100644
index 00000000..0921106d
--- /dev/null
+++ b/src/zstd/tests/fuzz/simple_round_trip.c
@@ -0,0 +1,95 @@
+/*
+ * Copyright (c) 2016-present, 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).
+ */
+
+/**
+ * This fuzz target performs a zstd round-trip test (compress & decompress),
+ * compares the result with the original, and calls abort() on corruption.
+ */
+
+#define ZSTD_STATIC_LINKING_ONLY
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include "fuzz_helpers.h"
+#include "zstd_helpers.h"
+
+static const int kMaxClevel = 19;
+
+static ZSTD_CCtx *cctx = NULL;
+static ZSTD_DCtx *dctx = NULL;
+static void* cBuf = NULL;
+static void* rBuf = NULL;
+static size_t bufSize = 0;
+static uint32_t seed;
+
+static size_t roundTripTest(void *result, size_t resultCapacity,
+                            void *compressed, size_t compressedCapacity,
+                            const void *src, size_t srcSize)
+{
+    size_t cSize;
+    if (FUZZ_rand(&seed) & 1) {
+        ZSTD_inBuffer in = {src, srcSize, 0};
+        ZSTD_outBuffer out = {compressed, compressedCapacity, 0};
+        size_t err;
+
+        ZSTD_CCtx_reset(cctx);
+        FUZZ_setRandomParameters(cctx, srcSize, &seed);
+        err = ZSTD_compress_generic(cctx, &out, &in, ZSTD_e_end);
+        FUZZ_ZASSERT(err);
+        FUZZ_ASSERT(err == 0);
+        cSize = out.pos;
+    } else {
+        int const cLevel = FUZZ_rand(&seed) % kMaxClevel;
+        cSize = ZSTD_compressCCtx(
+            cctx, compressed, compressedCapacity, src, srcSize, cLevel);
+    }
+    FUZZ_ZASSERT(cSize);
+    return ZSTD_decompressDCtx(dctx, result, resultCapacity, compressed, cSize);
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t *src, size_t size)
+{
+    size_t neededBufSize;
+
+    seed = FUZZ_seed(&src, &size);
+    neededBufSize = ZSTD_compressBound(size);
+
+    /* Allocate all buffers and contexts if not already allocated */
+    if (neededBufSize > bufSize) {
+        free(cBuf);
+        free(rBuf);
+        cBuf = malloc(neededBufSize);
+        rBuf = malloc(neededBufSize);
+        bufSize = neededBufSize;
+        FUZZ_ASSERT(cBuf && rBuf);
+    }
+    if (!cctx) {
+        cctx = ZSTD_createCCtx();
+        FUZZ_ASSERT(cctx);
+    }
+    if (!dctx) {
+        dctx = ZSTD_createDCtx();
+        FUZZ_ASSERT(dctx);
+    }
+
+    {
+        size_t const result =
+            roundTripTest(rBuf, neededBufSize, cBuf, neededBufSize, src, size);
+        FUZZ_ZASSERT(result);
+        FUZZ_ASSERT_MSG(result == size, "Incorrect regenerated size");
+        FUZZ_ASSERT_MSG(!memcmp(src, rBuf, size), "Corruption!");
+    }
+#ifndef STATEFUL_FUZZING
+    ZSTD_freeCCtx(cctx); cctx = NULL;
+    ZSTD_freeDCtx(dctx); dctx = NULL;
+#endif
+    return 0;
+}
diff --git a/src/zstd/tests/fuzz/stream_decompress.c b/src/zstd/tests/fuzz/stream_decompress.c
new file mode 100644
index 00000000..7ad57122
--- /dev/null
+++ b/src/zstd/tests/fuzz/stream_decompress.c
@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2016-present, 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).
+ */
+
+/**
+ * This fuzz target attempts to decompress the fuzzed data with the simple
+ * decompression function to ensure the decompressor never crashes.
+ */
+
+#define ZSTD_STATIC_LINKING_ONLY
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include "fuzz_helpers.h"
+#include "zstd.h"
+
+static size_t const kBufSize = ZSTD_BLOCKSIZE_MAX;
+
+static ZSTD_DStream *dstream = NULL;
+static void* buf = NULL;
+uint32_t seed;
+
+static ZSTD_outBuffer makeOutBuffer(void)
+{
+  ZSTD_outBuffer buffer = { buf, 0, 0 };
+
+  buffer.size = (FUZZ_rand(&seed) % kBufSize) + 1;
+  FUZZ_ASSERT(buffer.size <= kBufSize);
+
+  return buffer;
+}
+
+static ZSTD_inBuffer makeInBuffer(const uint8_t **src, size_t *size)
+{
+  ZSTD_inBuffer buffer = { *src, 0, 0 };
+
+  FUZZ_ASSERT(*size > 0);
+  buffer.size = (FUZZ_rand(&seed) % *size) + 1;
+  FUZZ_ASSERT(buffer.size <= *size);
+  *src += buffer.size;
+  *size -= buffer.size;
+
+  return buffer;
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t *src, size_t size)
+{
+    seed = FUZZ_seed(&src, &size);
+
+    /* Allocate all buffers and contexts if not already allocated */
+    if (!buf) {
+      buf = malloc(kBufSize);
+      FUZZ_ASSERT(buf);
+    }
+
+    if (!dstream) {
+        dstream = ZSTD_createDStream();
+        FUZZ_ASSERT(dstream);
+        FUZZ_ASSERT(!ZSTD_isError(ZSTD_initDStream(dstream)));
+    } else {
+        FUZZ_ASSERT(!ZSTD_isError(ZSTD_resetDStream(dstream)));
+    }
+
+    while (size > 0) {
+        ZSTD_inBuffer in = makeInBuffer(&src, &size);
+        while (in.pos != in.size) {
+            ZSTD_outBuffer out = makeOutBuffer();
+            size_t const rc = ZSTD_decompressStream(dstream, &out, &in);
+            if (ZSTD_isError(rc)) goto error;
+            if (rc == 0) FUZZ_ASSERT(!ZSTD_isError(ZSTD_resetDStream(dstream)));
+        }
+    }
+
+error:
+#ifndef STATEFUL_FUZZING
+    ZSTD_freeDStream(dstream); dstream = NULL;
+#endif
+    return 0;
+}
diff --git a/src/zstd/tests/fuzz/stream_round_trip.c b/src/zstd/tests/fuzz/stream_round_trip.c
new file mode 100644
index 00000000..72d70495
--- /dev/null
+++ b/src/zstd/tests/fuzz/stream_round_trip.c
@@ -0,0 +1,162 @@
+/*
+ * Copyright (c) 2016-present, 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).
+ */
+
+/**
+ * This fuzz target performs a zstd round-trip test (compress & decompress),
+ * compares the result with the original, and calls abort() on corruption.
+ */
+
+#define ZSTD_STATIC_LINKING_ONLY
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include "fuzz_helpers.h"
+#include "zstd_helpers.h"
+
+ZSTD_CCtx *cctx = NULL;
+static ZSTD_DCtx *dctx = NULL;
+static uint8_t* cBuf = NULL;
+static uint8_t* rBuf = NULL;
+static size_t bufSize = 0;
+static uint32_t seed;
+
+static ZSTD_outBuffer makeOutBuffer(uint8_t *dst, size_t capacity)
+{
+    ZSTD_outBuffer buffer = { dst, 0, 0 };
+
+    FUZZ_ASSERT(capacity > 0);
+    buffer.size = (FUZZ_rand(&seed) % capacity) + 1;
+    FUZZ_ASSERT(buffer.size <= capacity);
+
+    return buffer;
+}
+
+static ZSTD_inBuffer makeInBuffer(const uint8_t **src, size_t *size)
+{
+    ZSTD_inBuffer buffer = { *src, 0, 0 };
+
+    FUZZ_ASSERT(*size > 0);
+    buffer.size = (FUZZ_rand(&seed) % *size) + 1;
+    FUZZ_ASSERT(buffer.size <= *size);
+    *src += buffer.size;
+    *size -= buffer.size;
+
+    return buffer;
+}
+
+static size_t compress(uint8_t *dst, size_t capacity,
+                       const uint8_t *src, size_t srcSize)
+{
+    size_t dstSize = 0;
+    ZSTD_CCtx_reset(cctx);
+    FUZZ_setRandomParameters(cctx, srcSize, &seed);
+
+    while (srcSize > 0) {
+        ZSTD_inBuffer in = makeInBuffer(&src, &srcSize);
+        /* Mode controls the action. If mode == -1 we pick a new mode */
+        int mode = -1;
+        while (in.pos < in.size) {
+            ZSTD_outBuffer out = makeOutBuffer(dst, capacity);
+            /* Previous action finished, pick a new mode. */
+            if (mode == -1) mode = FUZZ_rand(&seed) % 10;
+            switch (mode) {
+                case 0: /* fall-though */
+                case 1: /* fall-though */
+                case 2: {
+                    size_t const ret =
+                        ZSTD_compress_generic(cctx, &out, &in, ZSTD_e_flush);
+                    FUZZ_ZASSERT(ret);
+                    if (ret == 0)
+                        mode = -1;
+                    break;
+                }
+                case 3: {
+                    size_t ret =
+                        ZSTD_compress_generic(cctx, &out, &in, ZSTD_e_end);
+                    FUZZ_ZASSERT(ret);
+                    /* Reset the compressor when the frame is finished */
+                    if (ret == 0) {
+                        ZSTD_CCtx_reset(cctx);
+                        if ((FUZZ_rand(&seed) & 7) == 0) {
+                            size_t const remaining = in.size - in.pos;
+                            FUZZ_setRandomParameters(cctx, remaining, &seed);
+                        }
+                        mode = -1;
+                    }
+                    break;
+                }
+                default: {
+                    size_t const ret =
+                        ZSTD_compress_generic(cctx, &out, &in, ZSTD_e_continue);
+                    FUZZ_ZASSERT(ret);
+                    mode = -1;
+                }
+            }
+            dst += out.pos;
+            dstSize += out.pos;
+            capacity -= out.pos;
+        }
+    }
+    for (;;) {
+        ZSTD_inBuffer in = {NULL, 0, 0};
+        ZSTD_outBuffer out = makeOutBuffer(dst, capacity);
+        size_t const ret = ZSTD_compress_generic(cctx, &out, &in, ZSTD_e_end);
+        FUZZ_ZASSERT(ret);
+
+        dst += out.pos;
+        dstSize += out.pos;
+        capacity -= out.pos;
+        if (ret == 0)
+            break;
+    }
+    return dstSize;
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t *src, size_t size)
+{
+    size_t neededBufSize;
+
+    seed = FUZZ_seed(&src, &size);
+    neededBufSize = ZSTD_compressBound(size) * 2;
+
+    /* Allocate all buffers and contexts if not already allocated */
+    if (neededBufSize > bufSize) {
+        free(cBuf);
+        free(rBuf);
+        cBuf = (uint8_t*)malloc(neededBufSize);
+        rBuf = (uint8_t*)malloc(neededBufSize);
+        bufSize = neededBufSize;
+        FUZZ_ASSERT(cBuf && rBuf);
+    }
+    if (!cctx) {
+        cctx = ZSTD_createCCtx();
+        FUZZ_ASSERT(cctx);
+    }
+    if (!dctx) {
+        dctx = ZSTD_createDCtx();
+        FUZZ_ASSERT(dctx);
+    }
+
+    {
+        size_t const cSize = compress(cBuf, neededBufSize, src, size);
+        size_t const rSize =
+            ZSTD_decompressDCtx(dctx, rBuf, neededBufSize, cBuf, cSize);
+        FUZZ_ZASSERT(rSize);
+        FUZZ_ASSERT_MSG(rSize == size, "Incorrect regenerated size");
+        FUZZ_ASSERT_MSG(!memcmp(src, rBuf, size), "Corruption!");
+    }
+
+#ifndef STATEFUL_FUZZING
+    ZSTD_freeCCtx(cctx); cctx = NULL;
+    ZSTD_freeDCtx(dctx); dctx = NULL;
+#endif
+    return 0;
+}
diff --git a/src/zstd/tests/fuzz/zstd_helpers.c b/src/zstd/tests/fuzz/zstd_helpers.c
new file mode 100644
index 00000000..60289847
--- /dev/null
+++ b/src/zstd/tests/fuzz/zstd_helpers.c
@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2016-present, 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).
+ */
+
+#define ZSTD_STATIC_LINKING_ONLY
+
+#include "zstd_helpers.h"
+#include "fuzz_helpers.h"
+#include "zstd.h"
+
+static void set(ZSTD_CCtx *cctx, ZSTD_cParameter param, unsigned value)
+{
+    FUZZ_ZASSERT(ZSTD_CCtx_setParameter(cctx, param, value));
+}
+
+static void setRand(ZSTD_CCtx *cctx, ZSTD_cParameter param, unsigned min,
+                    unsigned max, uint32_t *state) {
+    unsigned const value = FUZZ_rand32(state, min, max);
+    set(cctx, param, value);
+}
+
+ZSTD_compressionParameters FUZZ_randomCParams(size_t srcSize, uint32_t *state)
+{
+    /* Select compression parameters */
+    ZSTD_compressionParameters cParams;
+    cParams.windowLog = FUZZ_rand32(state, ZSTD_WINDOWLOG_MIN, 15);
+    cParams.hashLog = FUZZ_rand32(state, ZSTD_HASHLOG_MIN, 15);
+    cParams.chainLog = FUZZ_rand32(state, ZSTD_CHAINLOG_MIN, 16);
+    cParams.searchLog = FUZZ_rand32(state, ZSTD_SEARCHLOG_MIN, 9);
+    cParams.searchLength = FUZZ_rand32(state, ZSTD_SEARCHLENGTH_MIN,
+                                              ZSTD_SEARCHLENGTH_MAX);
+    cParams.targetLength = FUZZ_rand32(state, ZSTD_TARGETLENGTH_MIN,
+                                              ZSTD_TARGETLENGTH_MAX);
+    cParams.strategy = FUZZ_rand32(state, ZSTD_fast, ZSTD_btultra);
+    return ZSTD_adjustCParams(cParams, srcSize, 0);
+}
+
+ZSTD_frameParameters FUZZ_randomFParams(uint32_t *state)
+{
+    /* Select frame parameters */
+    ZSTD_frameParameters fParams;
+    fParams.contentSizeFlag = FUZZ_rand32(state, 0, 1);
+    fParams.checksumFlag = FUZZ_rand32(state, 0, 1);
+    fParams.noDictIDFlag = FUZZ_rand32(state, 0, 1);
+    return fParams;
+}
+
+ZSTD_parameters FUZZ_randomParams(size_t srcSize, uint32_t *state)
+{
+    ZSTD_parameters params;
+    params.cParams = FUZZ_randomCParams(srcSize, state);
+    params.fParams = FUZZ_randomFParams(state);
+    return params;
+}
+
+void FUZZ_setRandomParameters(ZSTD_CCtx *cctx, size_t srcSize, uint32_t *state)
+{
+    ZSTD_compressionParameters cParams = FUZZ_randomCParams(srcSize, state);
+    set(cctx, ZSTD_p_windowLog, cParams.windowLog);
+    set(cctx, ZSTD_p_hashLog, cParams.hashLog);
+    set(cctx, ZSTD_p_chainLog, cParams.chainLog);
+    set(cctx, ZSTD_p_searchLog, cParams.searchLog);
+    set(cctx, ZSTD_p_minMatch, cParams.searchLength);
+    set(cctx, ZSTD_p_targetLength, cParams.targetLength);
+    set(cctx, ZSTD_p_compressionStrategy, cParams.strategy);
+    /* Select frame parameters */
+    setRand(cctx, ZSTD_p_contentSizeFlag, 0, 1, state);
+    setRand(cctx, ZSTD_p_checksumFlag, 0, 1, state);
+    setRand(cctx, ZSTD_p_dictIDFlag, 0, 1, state);
+    /* Select long distance matchig parameters */
+    setRand(cctx, ZSTD_p_enableLongDistanceMatching, 0, 1, state);
+    setRand(cctx, ZSTD_p_ldmHashLog, ZSTD_HASHLOG_MIN, 16, state);
+    setRand(cctx, ZSTD_p_ldmMinMatch, ZSTD_LDM_MINMATCH_MIN,
+            ZSTD_LDM_MINMATCH_MAX, state);
+    setRand(cctx, ZSTD_p_ldmBucketSizeLog, 0, ZSTD_LDM_BUCKETSIZELOG_MAX,
+            state);
+    setRand(cctx, ZSTD_p_ldmHashEveryLog, 0,
+            ZSTD_WINDOWLOG_MAX - ZSTD_HASHLOG_MIN, state);
+}
diff --git a/src/zstd/tests/fuzz/zstd_helpers.h b/src/zstd/tests/fuzz/zstd_helpers.h
new file mode 100644
index 00000000..3856bebe
--- /dev/null
+++ b/src/zstd/tests/fuzz/zstd_helpers.h
@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2016-present, 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).
+ */
+
+/**
+ * Helper functions for fuzzing.
+ */
+
+#ifndef ZSTD_HELPERS_H
+#define ZSTD_HELPERS_H
+
+#include "zstd.h"
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void FUZZ_setRandomParameters(ZSTD_CCtx *cctx, size_t srcSize, uint32_t *state);
+
+ZSTD_compressionParameters FUZZ_randomCParams(size_t srcSize, uint32_t *state);
+ZSTD_frameParameters FUZZ_randomFParams(uint32_t *state);
+ZSTD_parameters FUZZ_randomParams(size_t srcSize, uint32_t *state);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* ZSTD_HELPERS_H */
diff --git a/src/zstd/tests/fuzzer.c b/src/zstd/tests/fuzzer.c
new file mode 100644
index 00000000..76df77af
--- /dev/null
+++ b/src/zstd/tests/fuzzer.c
@@ -0,0 +1,1643 @@
+/*
+ * Copyright (c) 2015-present, 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 specific
+**************************************/
+#ifdef _MSC_VER    /* Visual Studio */
+#  define _CRT_SECURE_NO_WARNINGS   /* fgets */
+#  pragma warning(disable : 4127)   /* disable: C4127: conditional expression is constant */
+#  pragma warning(disable : 4204)   /* disable: C4204: non-constant aggregate initializer */
+#endif
+
+
+/*-************************************
+*  Includes
+**************************************/
+#include <stdlib.h>       /* free */
+#include <stdio.h>        /* fgets, sscanf */
+#include <string.h>       /* strcmp */
+#include <time.h>         /* clock_t */
+#define ZSTD_STATIC_LINKING_ONLY  /* ZSTD_compressContinue, ZSTD_compressBlock */
+#include "zstd.h"         /* ZSTD_VERSION_STRING */
+#include "zstd_errors.h"  /* ZSTD_getErrorCode */
+#include "zstdmt_compress.h"
+#define ZDICT_STATIC_LINKING_ONLY
+#include "zdict.h"        /* ZDICT_trainFromBuffer */
+#include "datagen.h"      /* RDG_genBuffer */
+#include "mem.h"
+#define XXH_STATIC_LINKING_ONLY
+#include "xxhash.h"       /* XXH64 */
+
+
+/*-************************************
+*  Constants
+**************************************/
+#define KB *(1U<<10)
+#define MB *(1U<<20)
+#define GB *(1U<<30)
+
+static const U32 FUZ_compressibility_default = 50;
+static const U32 nbTestsDefault = 30000;
+
+
+/*-************************************
+*  Display Macros
+**************************************/
+#define DISPLAY(...)          fprintf(stdout, __VA_ARGS__)
+#define DISPLAYLEVEL(l, ...)  if (g_displayLevel>=l) { DISPLAY(__VA_ARGS__); }
+static U32 g_displayLevel = 2;
+
+#define DISPLAYUPDATE(l, ...) if (g_displayLevel>=l) { \
+            if ((FUZ_clockSpan(g_displayClock) > g_refreshRate) || (g_displayLevel>=4)) \
+            { g_displayClock = clock(); DISPLAY(__VA_ARGS__); \
+            if (g_displayLevel>=4) fflush(stdout); } }
+static const clock_t g_refreshRate = CLOCKS_PER_SEC / 6;
+static clock_t g_displayClock = 0;
+
+
+/*-*******************************************************
+*  Fuzzer functions
+*********************************************************/
+#define MIN(a,b) ((a)<(b)?(a):(b))
+#define MAX(a,b) ((a)>(b)?(a):(b))
+
+static clock_t FUZ_clockSpan(clock_t cStart)
+{
+    return clock() - cStart;   /* works even when overflow; max span ~ 30mn */
+}
+
+#define FUZ_rotl32(x,r) ((x << r) | (x >> (32 - r)))
+static unsigned FUZ_rand(unsigned* src)
+{
+    static const U32 prime1 = 2654435761U;
+    static const U32 prime2 = 2246822519U;
+    U32 rand32 = *src;
+    rand32 *= prime1;
+    rand32 += prime2;
+    rand32  = FUZ_rotl32(rand32, 13);
+    *src = rand32;
+    return rand32 >> 5;
+}
+
+static unsigned FUZ_highbit32(U32 v32)
+{
+    unsigned nbBits = 0;
+    if (v32==0) return 0;
+    while (v32) v32 >>= 1, nbBits++;
+    return nbBits;
+}
+
+
+/*=============================================
+*   Memory Tests
+=============================================*/
+#if defined(__APPLE__) && defined(__MACH__)
+
+#include <malloc/malloc.h>    /* malloc_size */
+
+typedef struct {
+    unsigned long long totalMalloc;
+    size_t currentMalloc;
+    size_t peakMalloc;
+    unsigned nbMalloc;
+    unsigned nbFree;
+} mallocCounter_t;
+
+static const mallocCounter_t INIT_MALLOC_COUNTER = { 0, 0, 0, 0, 0 };
+
+static void* FUZ_mallocDebug(void* counter, size_t size)
+{
+    mallocCounter_t* const mcPtr = (mallocCounter_t*)counter;
+    void* const ptr = malloc(size);
+    if (ptr==NULL) return NULL;
+    DISPLAYLEVEL(4, "allocating %u KB => effectively %u KB \n",
+        (U32)(size >> 10), (U32)(malloc_size(ptr) >> 10));  /* OS-X specific */
+    mcPtr->totalMalloc += size;
+    mcPtr->currentMalloc += size;
+    if (mcPtr->currentMalloc > mcPtr->peakMalloc)
+        mcPtr->peakMalloc = mcPtr->currentMalloc;
+    mcPtr->nbMalloc += 1;
+    return ptr;
+}
+
+static void FUZ_freeDebug(void* counter, void* address)
+{
+    mallocCounter_t* const mcPtr = (mallocCounter_t*)counter;
+    DISPLAYLEVEL(4, "freeing %u KB \n", (U32)(malloc_size(address) >> 10));
+    mcPtr->nbFree += 1;
+    mcPtr->currentMalloc -= malloc_size(address);  /* OS-X specific */
+    free(address);
+}
+
+static void FUZ_displayMallocStats(mallocCounter_t count)
+{
+    DISPLAYLEVEL(3, "peak:%6u KB,  nbMallocs:%2u, total:%6u KB \n",
+        (U32)(count.peakMalloc >> 10),
+        count.nbMalloc,
+        (U32)(count.totalMalloc >> 10));
+}
+
+#define CHECK_Z(f) {                               \
+    size_t const err = f;                          \
+    if (ZSTD_isError(err)) {                       \
+        DISPLAY("Error => %s : %s ",               \
+                #f, ZSTD_getErrorName(err));       \
+        exit(1);                                   \
+}   }
+
+static int FUZ_mallocTests(unsigned seed, double compressibility, unsigned part)
+{
+    size_t const inSize = 64 MB + 16 MB + 4 MB + 1 MB + 256 KB + 64 KB; /* 85.3 MB */
+    size_t const outSize = ZSTD_compressBound(inSize);
+    void* const inBuffer = malloc(inSize);
+    void* const outBuffer = malloc(outSize);
+
+    /* test only played in verbose mode, as they are long */
+    if (g_displayLevel<3) return 0;
+
+    /* Create compressible noise */
+    if (!inBuffer || !outBuffer) {
+        DISPLAY("Not enough memory, aborting\n");
+        exit(1);
+    }
+    RDG_genBuffer(inBuffer, inSize, compressibility, 0. /*auto*/, seed);
+
+    /* simple compression tests */
+    if (part <= 1)
+    {   int compressionLevel;
+        for (compressionLevel=1; compressionLevel<=6; compressionLevel++) {
+            mallocCounter_t malcount = INIT_MALLOC_COUNTER;
+            ZSTD_customMem const cMem = { FUZ_mallocDebug, FUZ_freeDebug, &malcount };
+            ZSTD_CCtx* const cctx = ZSTD_createCCtx_advanced(cMem);
+            CHECK_Z( ZSTD_compressCCtx(cctx, outBuffer, outSize, inBuffer, inSize, compressionLevel) );
+            ZSTD_freeCCtx(cctx);
+            DISPLAYLEVEL(3, "compressCCtx level %i : ", compressionLevel);
+            FUZ_displayMallocStats(malcount);
+    }   }
+
+    /* streaming compression tests */
+    if (part <= 2)
+    {   int compressionLevel;
+        for (compressionLevel=1; compressionLevel<=6; compressionLevel++) {
+            mallocCounter_t malcount = INIT_MALLOC_COUNTER;
+            ZSTD_customMem const cMem = { FUZ_mallocDebug, FUZ_freeDebug, &malcount };
+            ZSTD_CCtx* const cstream = ZSTD_createCStream_advanced(cMem);
+            ZSTD_outBuffer out = { outBuffer, outSize, 0 };
+            ZSTD_inBuffer in = { inBuffer, inSize, 0 };
+            CHECK_Z( ZSTD_initCStream(cstream, compressionLevel) );
+            CHECK_Z( ZSTD_compressStream(cstream, &out, &in) );
+            CHECK_Z( ZSTD_endStream(cstream, &out) );
+            ZSTD_freeCStream(cstream);
+            DISPLAYLEVEL(3, "compressStream level %i : ", compressionLevel);
+            FUZ_displayMallocStats(malcount);
+    }   }
+
+    /* advanced MT API test */
+    if (part <= 3)
+    {   U32 nbThreads;
+        for (nbThreads=1; nbThreads<=4; nbThreads++) {
+            int compressionLevel;
+            for (compressionLevel=1; compressionLevel<=6; compressionLevel++) {
+                mallocCounter_t malcount = INIT_MALLOC_COUNTER;
+                ZSTD_customMem const cMem = { FUZ_mallocDebug, FUZ_freeDebug, &malcount };
+                ZSTD_CCtx* const cctx = ZSTD_createCCtx_advanced(cMem);
+                ZSTD_outBuffer out = { outBuffer, outSize, 0 };
+                ZSTD_inBuffer in = { inBuffer, inSize, 0 };
+                CHECK_Z( ZSTD_CCtx_setParameter(cctx, ZSTD_p_compressionLevel, (U32)compressionLevel) );
+                CHECK_Z( ZSTD_CCtx_setParameter(cctx, ZSTD_p_nbThreads, nbThreads) );
+                while ( ZSTD_compress_generic(cctx, &out, &in, ZSTD_e_end) ) {}
+                ZSTD_freeCCtx(cctx);
+                DISPLAYLEVEL(3, "compress_generic,-T%u,end level %i : ",
+                                nbThreads, compressionLevel);
+                FUZ_displayMallocStats(malcount);
+    }   }   }
+
+    /* advanced MT streaming API test */
+    if (part <= 4)
+    {   U32 nbThreads;
+        for (nbThreads=1; nbThreads<=4; nbThreads++) {
+            int compressionLevel;
+            for (compressionLevel=1; compressionLevel<=6; compressionLevel++) {
+                mallocCounter_t malcount = INIT_MALLOC_COUNTER;
+                ZSTD_customMem const cMem = { FUZ_mallocDebug, FUZ_freeDebug, &malcount };
+                ZSTD_CCtx* const cctx = ZSTD_createCCtx_advanced(cMem);
+                ZSTD_outBuffer out = { outBuffer, outSize, 0 };
+                ZSTD_inBuffer in = { inBuffer, inSize, 0 };
+                CHECK_Z( ZSTD_CCtx_setParameter(cctx, ZSTD_p_compressionLevel, (U32)compressionLevel) );
+                CHECK_Z( ZSTD_CCtx_setParameter(cctx, ZSTD_p_nbThreads, nbThreads) );
+                CHECK_Z( ZSTD_compress_generic(cctx, &out, &in, ZSTD_e_continue) );
+                while ( ZSTD_compress_generic(cctx, &out, &in, ZSTD_e_end) ) {}
+                ZSTD_freeCCtx(cctx);
+                DISPLAYLEVEL(3, "compress_generic,-T%u,continue level %i : ",
+                                nbThreads, compressionLevel);
+                FUZ_displayMallocStats(malcount);
+    }   }   }
+
+    return 0;
+}
+
+#else
+
+static int FUZ_mallocTests(unsigned seed, double compressibility, unsigned part)
+{
+    (void)seed; (void)compressibility; (void)part;
+    return 0;
+}
+
+#endif
+
+/*=============================================
+*   Unit tests
+=============================================*/
+
+#define CHECK_V(var, fn)  size_t const var = fn; if (ZSTD_isError(var)) goto _output_error
+#define CHECK(fn)  { CHECK_V(err, fn); }
+#define CHECKPLUS(var, fn, more)  { CHECK_V(var, fn); more; }
+
+static int basicUnitTests(U32 seed, double compressibility)
+{
+    size_t const CNBuffSize = 5 MB;
+    void* const CNBuffer = malloc(CNBuffSize);
+    size_t const compressedBufferSize = ZSTD_compressBound(CNBuffSize);
+    void* const compressedBuffer = malloc(compressedBufferSize);
+    void* const decodedBuffer = malloc(CNBuffSize);
+    ZSTD_DCtx* dctx = ZSTD_createDCtx();
+    int testResult = 0;
+    U32 testNb=0;
+    size_t cSize;
+
+    /* Create compressible noise */
+    if (!CNBuffer || !compressedBuffer || !decodedBuffer) {
+        DISPLAY("Not enough memory, aborting\n");
+        testResult = 1;
+        goto _end;
+    }
+    RDG_genBuffer(CNBuffer, CNBuffSize, compressibility, 0., seed);
+
+    /* Basic tests */
+    DISPLAYLEVEL(4, "test%3i : ZSTD_getErrorName : ", testNb++);
+    {   const char* errorString = ZSTD_getErrorName(0);
+        DISPLAYLEVEL(4, "OK : %s \n", errorString);
+    }
+
+    DISPLAYLEVEL(4, "test%3i : ZSTD_getErrorName with wrong value : ", testNb++);
+    {   const char* errorString = ZSTD_getErrorName(499);
+        DISPLAYLEVEL(4, "OK : %s \n", errorString);
+    }
+
+
+    DISPLAYLEVEL(4, "test%3i : compress %u bytes : ", testNb++, (U32)CNBuffSize);
+    {   ZSTD_CCtx* cctx = ZSTD_createCCtx();
+        if (cctx==NULL) goto _output_error;
+        CHECKPLUS(r, ZSTD_compressCCtx(cctx,
+                            compressedBuffer, compressedBufferSize,
+                            CNBuffer, CNBuffSize, 1),
+                  cSize=r );
+        DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
+
+        DISPLAYLEVEL(4, "test%3i : size of cctx for level 1 : ", testNb++);
+        {   size_t const cctxSize = ZSTD_sizeof_CCtx(cctx);
+            DISPLAYLEVEL(4, "%u bytes \n", (U32)cctxSize);
+        }
+        ZSTD_freeCCtx(cctx);
+    }
+
+
+    DISPLAYLEVEL(4, "test%3i : ZSTD_getFrameContentSize test : ", testNb++);
+    {   unsigned long long const rSize = ZSTD_getFrameContentSize(compressedBuffer, cSize);
+        if (rSize != CNBuffSize) goto _output_error;
+    }
+    DISPLAYLEVEL(4, "OK \n");
+
+    DISPLAYLEVEL(4, "test%3i : ZSTD_findDecompressedSize test : ", testNb++);
+    {   unsigned long long const rSize = ZSTD_findDecompressedSize(compressedBuffer, cSize);
+        if (rSize != CNBuffSize) goto _output_error;
+    }
+    DISPLAYLEVEL(4, "OK \n");
+
+    DISPLAYLEVEL(4, "test%3i : decompress %u bytes : ", testNb++, (U32)CNBuffSize);
+    { size_t const r = ZSTD_decompress(decodedBuffer, CNBuffSize, compressedBuffer, cSize);
+      if (r != CNBuffSize) goto _output_error; }
+    DISPLAYLEVEL(4, "OK \n");
+
+    DISPLAYLEVEL(4, "test%3i : check decompressed result : ", testNb++);
+    {   size_t u;
+        for (u=0; u<CNBuffSize; u++) {
+            if (((BYTE*)decodedBuffer)[u] != ((BYTE*)CNBuffer)[u]) goto _output_error;;
+    }   }
+    DISPLAYLEVEL(4, "OK \n");
+
+
+    DISPLAYLEVEL(4, "test%3i : decompress with null dict : ", testNb++);
+    { size_t const r = ZSTD_decompress_usingDict(dctx, decodedBuffer, CNBuffSize, compressedBuffer, cSize, NULL, 0);
+      if (r != CNBuffSize) goto _output_error; }
+    DISPLAYLEVEL(4, "OK \n");
+
+    DISPLAYLEVEL(4, "test%3i : decompress with null DDict : ", testNb++);
+    { size_t const r = ZSTD_decompress_usingDDict(dctx, decodedBuffer, CNBuffSize, compressedBuffer, cSize, NULL);
+      if (r != CNBuffSize) goto _output_error; }
+    DISPLAYLEVEL(4, "OK \n");
+
+    DISPLAYLEVEL(4, "test%3i : decompress with 1 missing byte : ", testNb++);
+    { size_t const r = ZSTD_decompress(decodedBuffer, CNBuffSize, compressedBuffer, cSize-1);
+      if (!ZSTD_isError(r)) goto _output_error;
+      if (ZSTD_getErrorCode((size_t)r) != ZSTD_error_srcSize_wrong) goto _output_error; }
+    DISPLAYLEVEL(4, "OK \n");
+
+    DISPLAYLEVEL(4, "test%3i : decompress with 1 too much byte : ", testNb++);
+    { size_t const r = ZSTD_decompress(decodedBuffer, CNBuffSize, compressedBuffer, cSize+1);
+      if (!ZSTD_isError(r)) goto _output_error;
+      if (ZSTD_getErrorCode(r) != ZSTD_error_srcSize_wrong) goto _output_error; }
+    DISPLAYLEVEL(4, "OK \n");
+
+
+    /* Static CCtx tests */
+#define STATIC_CCTX_LEVEL 3
+    DISPLAYLEVEL(4, "test%3i : create static CCtx for level %u :", testNb++, STATIC_CCTX_LEVEL);
+    {   size_t const staticCCtxSize = ZSTD_estimateCStreamSize(STATIC_CCTX_LEVEL);
+        void* const staticCCtxBuffer = malloc(staticCCtxSize);
+        size_t const staticDCtxSize = ZSTD_estimateDCtxSize();
+        void* const staticDCtxBuffer = malloc(staticDCtxSize);
+        if (staticCCtxBuffer==NULL || staticDCtxBuffer==NULL) {
+            free(staticCCtxBuffer);
+            free(staticDCtxBuffer);
+            DISPLAY("Not enough memory, aborting\n");
+            testResult = 1;
+            goto _end;
+        }
+        {   ZSTD_CCtx* staticCCtx = ZSTD_initStaticCCtx(staticCCtxBuffer, staticCCtxSize);
+            ZSTD_DCtx* staticDCtx = ZSTD_initStaticDCtx(staticDCtxBuffer, staticDCtxSize);
+            if ((staticCCtx==NULL) || (staticDCtx==NULL)) goto _output_error;
+            DISPLAYLEVEL(4, "OK \n");
+
+            DISPLAYLEVEL(4, "test%3i : init CCtx for level %u : ", testNb++, STATIC_CCTX_LEVEL);
+            { size_t const r = ZSTD_compressBegin(staticCCtx, STATIC_CCTX_LEVEL);
+              if (ZSTD_isError(r)) goto _output_error; }
+            DISPLAYLEVEL(4, "OK \n");
+
+            DISPLAYLEVEL(4, "test%3i : simple compression test with static CCtx : ", testNb++);
+            CHECKPLUS(r, ZSTD_compressCCtx(staticCCtx,
+                            compressedBuffer, compressedBufferSize,
+                            CNBuffer, CNBuffSize, STATIC_CCTX_LEVEL),
+                      cSize=r );
+            DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n",
+                            (U32)cSize, (double)cSize/CNBuffSize*100);
+
+            DISPLAYLEVEL(4, "test%3i : simple decompression test with static DCtx : ", testNb++);
+            { size_t const r = ZSTD_decompressDCtx(staticDCtx,
+                                                decodedBuffer, CNBuffSize,
+                                                compressedBuffer, cSize);
+              if (r != CNBuffSize) goto _output_error; }
+            DISPLAYLEVEL(4, "OK \n");
+
+            DISPLAYLEVEL(4, "test%3i : check decompressed result : ", testNb++);
+            {   size_t u;
+                for (u=0; u<CNBuffSize; u++) {
+                    if (((BYTE*)decodedBuffer)[u] != ((BYTE*)CNBuffer)[u])
+                        goto _output_error;;
+            }   }
+            DISPLAYLEVEL(4, "OK \n");
+
+            DISPLAYLEVEL(4, "test%3i : init CCtx for too large level (must fail) : ", testNb++);
+            { size_t const r = ZSTD_compressBegin(staticCCtx, ZSTD_maxCLevel());
+              if (!ZSTD_isError(r)) goto _output_error; }
+            DISPLAYLEVEL(4, "OK \n");
+
+            DISPLAYLEVEL(4, "test%3i : init CCtx for small level %u (should work again) : ", testNb++, 1);
+            { size_t const r = ZSTD_compressBegin(staticCCtx, 1);
+              if (ZSTD_isError(r)) goto _output_error; }
+            DISPLAYLEVEL(4, "OK \n");
+
+            DISPLAYLEVEL(4, "test%3i : init CStream for small level %u : ", testNb++, 1);
+            { size_t const r = ZSTD_initCStream(staticCCtx, 1);
+              if (ZSTD_isError(r)) goto _output_error; }
+            DISPLAYLEVEL(4, "OK \n");
+
+            DISPLAYLEVEL(4, "test%3i : init CStream with dictionary (should fail) : ", testNb++);
+            { size_t const r = ZSTD_initCStream_usingDict(staticCCtx, CNBuffer, 64 KB, 1);
+              if (!ZSTD_isError(r)) goto _output_error; }
+            DISPLAYLEVEL(4, "OK \n");
+
+            DISPLAYLEVEL(4, "test%3i : init DStream (should fail) : ", testNb++);
+            { size_t const r = ZSTD_initDStream(staticDCtx);
+              if (ZSTD_isError(r)) goto _output_error; }
+            {   ZSTD_outBuffer output = { decodedBuffer, CNBuffSize, 0 };
+                ZSTD_inBuffer input = { compressedBuffer, ZSTD_FRAMEHEADERSIZE_MAX+1, 0 };
+                size_t const r = ZSTD_decompressStream(staticDCtx, &output, &input);
+                if (!ZSTD_isError(r)) goto _output_error;
+            }
+            DISPLAYLEVEL(4, "OK \n");
+        }
+        free(staticCCtxBuffer);
+        free(staticDCtxBuffer);
+    }
+
+
+
+    /* ZSTDMT simple MT compression test */
+    DISPLAYLEVEL(4, "test%3i : create ZSTDMT CCtx : ", testNb++);
+    {   ZSTDMT_CCtx* mtctx = ZSTDMT_createCCtx(2);
+        if (mtctx==NULL) {
+            DISPLAY("mtctx : mot enough memory, aborting \n");
+            testResult = 1;
+            goto _end;
+        }
+        DISPLAYLEVEL(4, "OK \n");
+
+        DISPLAYLEVEL(4, "test%3i : compress %u bytes with 2 threads : ", testNb++, (U32)CNBuffSize);
+        CHECKPLUS(r, ZSTDMT_compressCCtx(mtctx,
+                                compressedBuffer, compressedBufferSize,
+                                CNBuffer, CNBuffSize,
+                                1),
+                  cSize=r );
+        DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
+
+        DISPLAYLEVEL(4, "test%3i : decompressed size test : ", testNb++);
+        {   unsigned long long const rSize = ZSTD_getFrameContentSize(compressedBuffer, cSize);
+            if (rSize != CNBuffSize)  {
+                DISPLAY("ZSTD_getFrameContentSize incorrect : %u != %u \n", (U32)rSize, (U32)CNBuffSize);
+                goto _output_error;
+        }   }
+        DISPLAYLEVEL(4, "OK \n");
+
+        DISPLAYLEVEL(4, "test%3i : decompress %u bytes : ", testNb++, (U32)CNBuffSize);
+        { size_t const r = ZSTD_decompress(decodedBuffer, CNBuffSize, compressedBuffer, cSize);
+          if (r != CNBuffSize) goto _output_error; }
+        DISPLAYLEVEL(4, "OK \n");
+
+        DISPLAYLEVEL(4, "test%3i : check decompressed result : ", testNb++);
+        {   size_t u;
+            for (u=0; u<CNBuffSize; u++) {
+                if (((BYTE*)decodedBuffer)[u] != ((BYTE*)CNBuffer)[u]) goto _output_error;;
+        }   }
+        DISPLAYLEVEL(4, "OK \n");
+
+        DISPLAYLEVEL(4, "test%3i : compress -T2 with checksum : ", testNb++);
+        {   ZSTD_parameters params = ZSTD_getParams(1, CNBuffSize, 0);
+            params.fParams.checksumFlag = 1;
+            params.fParams.contentSizeFlag = 1;
+            CHECKPLUS(r, ZSTDMT_compress_advanced(mtctx,
+                                    compressedBuffer, compressedBufferSize,
+                                    CNBuffer, CNBuffSize,
+                                    NULL, params, 3 /*overlapRLog*/),
+                      cSize=r );
+        }
+        DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
+
+        DISPLAYLEVEL(4, "test%3i : decompress %u bytes : ", testNb++, (U32)CNBuffSize);
+        { size_t const r = ZSTD_decompress(decodedBuffer, CNBuffSize, compressedBuffer, cSize);
+          if (r != CNBuffSize) goto _output_error; }
+        DISPLAYLEVEL(4, "OK \n");
+
+        ZSTDMT_freeCCtx(mtctx);
+    }
+
+
+    /* Simple API multiframe test */
+    DISPLAYLEVEL(4, "test%3i : compress multiple frames : ", testNb++);
+    {   size_t off = 0;
+        int i;
+        int const segs = 4;
+        /* only use the first half so we don't push against size limit of compressedBuffer */
+        size_t const segSize = (CNBuffSize / 2) / segs;
+        for (i = 0; i < segs; i++) {
+            CHECK_V(r, ZSTD_compress(
+                            (BYTE *)compressedBuffer + off, CNBuffSize - off,
+                            (BYTE *)CNBuffer + segSize * i,
+                            segSize, 5));
+            off += r;
+            if (i == segs/2) {
+                /* insert skippable frame */
+                const U32 skipLen = 128 KB;
+                MEM_writeLE32((BYTE*)compressedBuffer + off, ZSTD_MAGIC_SKIPPABLE_START);
+                MEM_writeLE32((BYTE*)compressedBuffer + off + 4, skipLen);
+                off += skipLen + ZSTD_skippableHeaderSize;
+            }
+        }
+        cSize = off;
+    }
+    DISPLAYLEVEL(4, "OK \n");
+
+    DISPLAYLEVEL(4, "test%3i : get decompressed size of multiple frames : ", testNb++);
+    {   unsigned long long const r = ZSTD_findDecompressedSize(compressedBuffer, cSize);
+        if (r != CNBuffSize / 2) goto _output_error; }
+    DISPLAYLEVEL(4, "OK \n");
+
+    DISPLAYLEVEL(4, "test%3i : decompress multiple frames : ", testNb++);
+    {   CHECK_V(r, ZSTD_decompress(decodedBuffer, CNBuffSize, compressedBuffer, cSize));
+        if (r != CNBuffSize / 2) goto _output_error; }
+    DISPLAYLEVEL(4, "OK \n");
+
+    DISPLAYLEVEL(4, "test%3i : check decompressed result : ", testNb++);
+    if (memcmp(decodedBuffer, CNBuffer, CNBuffSize / 2) != 0) goto _output_error;
+    DISPLAYLEVEL(4, "OK \n");
+
+    /* Dictionary and CCtx Duplication tests */
+    {   ZSTD_CCtx* const ctxOrig = ZSTD_createCCtx();
+        ZSTD_CCtx* const ctxDuplicated = ZSTD_createCCtx();
+        static const size_t dictSize = 551;
+
+        DISPLAYLEVEL(4, "test%3i : copy context too soon : ", testNb++);
+        { size_t const copyResult = ZSTD_copyCCtx(ctxDuplicated, ctxOrig, 0);
+          if (!ZSTD_isError(copyResult)) goto _output_error; }   /* error must be detected */
+        DISPLAYLEVEL(4, "OK \n");
+
+        DISPLAYLEVEL(4, "test%3i : load dictionary into context : ", testNb++);
+        CHECK( ZSTD_compressBegin_usingDict(ctxOrig, CNBuffer, dictSize, 2) );
+        CHECK( ZSTD_copyCCtx(ctxDuplicated, ctxOrig, 0) ); /* Begin_usingDict implies unknown srcSize, so match that */
+        DISPLAYLEVEL(4, "OK \n");
+
+        DISPLAYLEVEL(4, "test%3i : compress with flat dictionary : ", testNb++);
+        cSize = 0;
+        CHECKPLUS(r, ZSTD_compressEnd(ctxOrig, compressedBuffer, compressedBufferSize,
+                                           (const char*)CNBuffer + dictSize, CNBuffSize - dictSize),
+                  cSize += r);
+        DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
+
+        DISPLAYLEVEL(4, "test%3i : frame built with flat dictionary should be decompressible : ", testNb++);
+        CHECKPLUS(r, ZSTD_decompress_usingDict(dctx,
+                                       decodedBuffer, CNBuffSize,
+                                       compressedBuffer, cSize,
+                                       CNBuffer, dictSize),
+                  if (r != CNBuffSize - dictSize) goto _output_error);
+        DISPLAYLEVEL(4, "OK \n");
+
+        DISPLAYLEVEL(4, "test%3i : compress with duplicated context : ", testNb++);
+        {   size_t const cSizeOrig = cSize;
+            cSize = 0;
+            CHECKPLUS(r, ZSTD_compressEnd(ctxDuplicated, compressedBuffer, compressedBufferSize,
+                                               (const char*)CNBuffer + dictSize, CNBuffSize - dictSize),
+                      cSize += r);
+            if (cSize != cSizeOrig) goto _output_error;   /* should be identical ==> same size */
+        }
+        DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
+
+        DISPLAYLEVEL(4, "test%3i : frame built with duplicated context should be decompressible : ", testNb++);
+        CHECKPLUS(r, ZSTD_decompress_usingDict(dctx,
+                                           decodedBuffer, CNBuffSize,
+                                           compressedBuffer, cSize,
+                                           CNBuffer, dictSize),
+                  if (r != CNBuffSize - dictSize) goto _output_error);
+        DISPLAYLEVEL(4, "OK \n");
+
+        DISPLAYLEVEL(4, "test%3i : decompress with DDict : ", testNb++);
+        {   ZSTD_DDict* const ddict = ZSTD_createDDict(CNBuffer, dictSize);
+            size_t const r = ZSTD_decompress_usingDDict(dctx, decodedBuffer, CNBuffSize, compressedBuffer, cSize, ddict);
+            if (r != CNBuffSize - dictSize) goto _output_error;
+            DISPLAYLEVEL(4, "OK (size of DDict : %u) \n", (U32)ZSTD_sizeof_DDict(ddict));
+            ZSTD_freeDDict(ddict);
+        }
+
+        DISPLAYLEVEL(4, "test%3i : decompress with static DDict : ", testNb++);
+        {   size_t const ddictBufferSize = ZSTD_estimateDDictSize(dictSize, ZSTD_dlm_byCopy);
+            void* ddictBuffer = malloc(ddictBufferSize);
+            if (ddictBuffer == NULL) goto _output_error;
+            {   ZSTD_DDict* const ddict = ZSTD_initStaticDDict(ddictBuffer, ddictBufferSize, CNBuffer, dictSize, ZSTD_dlm_byCopy);
+                size_t const r = ZSTD_decompress_usingDDict(dctx, decodedBuffer, CNBuffSize, compressedBuffer, cSize, ddict);
+                if (r != CNBuffSize - dictSize) goto _output_error;
+            }
+            free(ddictBuffer);
+            DISPLAYLEVEL(4, "OK (size of static DDict : %u) \n", (U32)ddictBufferSize);
+        }
+
+        DISPLAYLEVEL(4, "test%3i : check content size on duplicated context : ", testNb++);
+        {   size_t const testSize = CNBuffSize / 3;
+            {   ZSTD_parameters p = ZSTD_getParams(2, testSize, dictSize);
+                p.fParams.contentSizeFlag = 1;
+                CHECK( ZSTD_compressBegin_advanced(ctxOrig, CNBuffer, dictSize, p, testSize-1) );
+            }
+            CHECK( ZSTD_copyCCtx(ctxDuplicated, ctxOrig, testSize) );
+
+            CHECKPLUS(r, ZSTD_compressEnd(ctxDuplicated, compressedBuffer, ZSTD_compressBound(testSize),
+                                          (const char*)CNBuffer + dictSize, testSize),
+                      cSize = r);
+            {   ZSTD_frameHeader zfh;
+                if (ZSTD_getFrameHeader(&zfh, compressedBuffer, cSize)) goto _output_error;
+                if ((zfh.frameContentSize != testSize) && (zfh.frameContentSize != 0)) goto _output_error;
+        }   }
+        DISPLAYLEVEL(4, "OK \n");
+
+        ZSTD_freeCCtx(ctxOrig);
+        ZSTD_freeCCtx(ctxDuplicated);
+    }
+
+    /* Dictionary and dictBuilder tests */
+    {   ZSTD_CCtx* const cctx = ZSTD_createCCtx();
+        size_t dictSize = 16 KB;
+        void* dictBuffer = malloc(dictSize);
+        size_t const totalSampleSize = 1 MB;
+        size_t const sampleUnitSize = 8 KB;
+        U32 const nbSamples = (U32)(totalSampleSize / sampleUnitSize);
+        size_t* const samplesSizes = (size_t*) malloc(nbSamples * sizeof(size_t));
+        U32 dictID;
+
+        if (dictBuffer==NULL || samplesSizes==NULL) {
+            free(dictBuffer);
+            free(samplesSizes);
+            goto _output_error;
+        }
+
+        DISPLAYLEVEL(4, "test%3i : dictBuilder : ", testNb++);
+        { U32 u; for (u=0; u<nbSamples; u++) samplesSizes[u] = sampleUnitSize; }
+        dictSize = ZDICT_trainFromBuffer(dictBuffer, dictSize,
+                                         CNBuffer, samplesSizes, nbSamples);
+        if (ZDICT_isError(dictSize)) goto _output_error;
+        DISPLAYLEVEL(4, "OK, created dictionary of size %u \n", (U32)dictSize);
+
+        DISPLAYLEVEL(4, "test%3i : check dictID : ", testNb++);
+        dictID = ZDICT_getDictID(dictBuffer, dictSize);
+        if (dictID==0) goto _output_error;
+        DISPLAYLEVEL(4, "OK : %u \n", dictID);
+
+        DISPLAYLEVEL(4, "test%3i : compress with dictionary : ", testNb++);
+        cSize = ZSTD_compress_usingDict(cctx, compressedBuffer, compressedBufferSize,
+                                        CNBuffer, CNBuffSize,
+                                        dictBuffer, dictSize, 4);
+        if (ZSTD_isError(cSize)) goto _output_error;
+        DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
+
+        DISPLAYLEVEL(4, "test%3i : retrieve dictID from dictionary : ", testNb++);
+        {   U32 const did = ZSTD_getDictID_fromDict(dictBuffer, dictSize);
+            if (did != dictID) goto _output_error;   /* non-conformant (content-only) dictionary */
+        }
+        DISPLAYLEVEL(4, "OK \n");
+
+        DISPLAYLEVEL(4, "test%3i : retrieve dictID from frame : ", testNb++);
+        {   U32 const did = ZSTD_getDictID_fromFrame(compressedBuffer, cSize);
+            if (did != dictID) goto _output_error;   /* non-conformant (content-only) dictionary */
+        }
+        DISPLAYLEVEL(4, "OK \n");
+
+        DISPLAYLEVEL(4, "test%3i : frame built with dictionary should be decompressible : ", testNb++);
+        CHECKPLUS(r, ZSTD_decompress_usingDict(dctx,
+                                       decodedBuffer, CNBuffSize,
+                                       compressedBuffer, cSize,
+                                       dictBuffer, dictSize),
+                  if (r != CNBuffSize) goto _output_error);
+        DISPLAYLEVEL(4, "OK \n");
+
+        DISPLAYLEVEL(4, "test%3i : estimate CDict size : ", testNb++);
+        {   ZSTD_compressionParameters const cParams = ZSTD_getCParams(1, CNBuffSize, dictSize);
+            size_t const estimatedSize = ZSTD_estimateCDictSize_advanced(dictSize, cParams, ZSTD_dlm_byRef);
+            DISPLAYLEVEL(4, "OK : %u \n", (U32)estimatedSize);
+        }
+
+        DISPLAYLEVEL(4, "test%3i : compress with CDict ", testNb++);
+        {   ZSTD_compressionParameters const cParams = ZSTD_getCParams(1, CNBuffSize, dictSize);
+            ZSTD_CDict* const cdict = ZSTD_createCDict_advanced(dictBuffer, dictSize,
+                                            ZSTD_dlm_byRef, ZSTD_dm_auto,
+                                            cParams, ZSTD_defaultCMem);
+            DISPLAYLEVEL(4, "(size : %u) : ", (U32)ZSTD_sizeof_CDict(cdict));
+            cSize = ZSTD_compress_usingCDict(cctx, compressedBuffer, compressedBufferSize,
+                                                 CNBuffer, CNBuffSize, cdict);
+            ZSTD_freeCDict(cdict);
+            if (ZSTD_isError(cSize)) goto _output_error;
+        }
+        DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
+
+        DISPLAYLEVEL(4, "test%3i : retrieve dictID from frame : ", testNb++);
+        {   U32 const did = ZSTD_getDictID_fromFrame(compressedBuffer, cSize);
+            if (did != dictID) goto _output_error;   /* non-conformant (content-only) dictionary */
+        }
+        DISPLAYLEVEL(4, "OK \n");
+
+        DISPLAYLEVEL(4, "test%3i : frame built with dictionary should be decompressible : ", testNb++);
+        CHECKPLUS(r, ZSTD_decompress_usingDict(dctx,
+                                       decodedBuffer, CNBuffSize,
+                                       compressedBuffer, cSize,
+                                       dictBuffer, dictSize),
+                  if (r != CNBuffSize) goto _output_error);
+        DISPLAYLEVEL(4, "OK \n");
+
+        DISPLAYLEVEL(4, "test%3i : compress with static CDict : ", testNb++);
+        {   ZSTD_compressionParameters const cParams = ZSTD_getCParams(1, CNBuffSize, dictSize);
+            size_t const cdictSize = ZSTD_estimateCDictSize_advanced(dictSize, cParams, ZSTD_dlm_byCopy);
+            void* const cdictBuffer = malloc(cdictSize);
+            if (cdictBuffer==NULL) goto _output_error;
+            {   ZSTD_CDict* const cdict = ZSTD_initStaticCDict(cdictBuffer, cdictSize,
+                                            dictBuffer, dictSize,
+                                            ZSTD_dlm_byCopy, ZSTD_dm_auto,
+                                            cParams);
+                if (cdict == NULL) {
+                    DISPLAY("ZSTD_initStaticCDict failed ");
+                    goto _output_error;
+                }
+                cSize = ZSTD_compress_usingCDict(cctx,
+                                compressedBuffer, compressedBufferSize,
+                                CNBuffer, CNBuffSize, cdict);
+                if (ZSTD_isError(cSize)) {
+                    DISPLAY("ZSTD_compress_usingCDict failed ");
+                    goto _output_error;
+            }   }
+            free(cdictBuffer);
+        }
+        DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
+
+        DISPLAYLEVEL(4, "test%3i : ZSTD_compress_usingCDict_advanced, no contentSize, no dictID : ", testNb++);
+        {   ZSTD_frameParameters const fParams = { 0 /* frameSize */, 1 /* checksum */, 1 /* noDictID*/ };
+            ZSTD_compressionParameters const cParams = ZSTD_getCParams(1, CNBuffSize, dictSize);
+            ZSTD_CDict* const cdict = ZSTD_createCDict_advanced(dictBuffer, dictSize, ZSTD_dlm_byRef, ZSTD_dm_auto, cParams, ZSTD_defaultCMem);
+            cSize = ZSTD_compress_usingCDict_advanced(cctx, compressedBuffer, compressedBufferSize,
+                                                 CNBuffer, CNBuffSize, cdict, fParams);
+            ZSTD_freeCDict(cdict);
+            if (ZSTD_isError(cSize)) goto _output_error;
+        }
+        DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
+
+        DISPLAYLEVEL(4, "test%3i : try retrieving contentSize from frame : ", testNb++);
+        {   U64 const contentSize = ZSTD_getFrameContentSize(compressedBuffer, cSize);
+            if (contentSize != ZSTD_CONTENTSIZE_UNKNOWN) goto _output_error;
+        }
+        DISPLAYLEVEL(4, "OK (unknown)\n");
+
+        DISPLAYLEVEL(4, "test%3i : frame built without dictID should be decompressible : ", testNb++);
+        CHECKPLUS(r, ZSTD_decompress_usingDict(dctx,
+                                       decodedBuffer, CNBuffSize,
+                                       compressedBuffer, cSize,
+                                       dictBuffer, dictSize),
+                  if (r != CNBuffSize) goto _output_error);
+        DISPLAYLEVEL(4, "OK \n");
+
+        DISPLAYLEVEL(4, "test%3i : ZSTD_compress_advanced, no dictID : ", testNb++);
+        {   ZSTD_parameters p = ZSTD_getParams(3, CNBuffSize, dictSize);
+            p.fParams.noDictIDFlag = 1;
+            cSize = ZSTD_compress_advanced(cctx, compressedBuffer, compressedBufferSize,
+                                           CNBuffer, CNBuffSize,
+                                           dictBuffer, dictSize, p);
+            if (ZSTD_isError(cSize)) goto _output_error;
+        }
+        DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/CNBuffSize*100);
+
+        DISPLAYLEVEL(4, "test%3i : frame built without dictID should be decompressible : ", testNb++);
+        CHECKPLUS(r, ZSTD_decompress_usingDict(dctx,
+                                       decodedBuffer, CNBuffSize,
+                                       compressedBuffer, cSize,
+                                       dictBuffer, dictSize),
+                  if (r != CNBuffSize) goto _output_error);
+        DISPLAYLEVEL(4, "OK \n");
+
+        DISPLAYLEVEL(4, "test%3i : dictionary containing only header should return error : ", testNb++);
+        {
+          const size_t ret = ZSTD_decompress_usingDict(
+              dctx, decodedBuffer, CNBuffSize, compressedBuffer, cSize,
+              "\x37\xa4\x30\xec\x11\x22\x33\x44", 8);
+          if (ZSTD_getErrorCode(ret) != ZSTD_error_dictionary_corrupted) goto _output_error;
+        }
+        DISPLAYLEVEL(4, "OK \n");
+
+        DISPLAYLEVEL(4, "test%3i : Building cdict w/ ZSTD_dm_fullDict on a good dictionary : ", testNb++);
+        {   ZSTD_compressionParameters const cParams = ZSTD_getCParams(1, CNBuffSize, dictSize);
+            ZSTD_CDict* const cdict = ZSTD_createCDict_advanced(dictBuffer, dictSize, ZSTD_dlm_byRef, ZSTD_dm_fullDict, cParams, ZSTD_defaultCMem);
+            if (cdict==NULL) goto _output_error;
+            ZSTD_freeCDict(cdict);
+        }
+        DISPLAYLEVEL(4, "OK \n");
+
+        DISPLAYLEVEL(4, "test%3i : Building cdict w/ ZSTD_dm_fullDict on a rawContent (must fail) : ", testNb++);
+        {   ZSTD_compressionParameters const cParams = ZSTD_getCParams(1, CNBuffSize, dictSize);
+            ZSTD_CDict* const cdict = ZSTD_createCDict_advanced((const char*)dictBuffer+1, dictSize-1, ZSTD_dlm_byRef, ZSTD_dm_fullDict, cParams, ZSTD_defaultCMem);
+            if (cdict!=NULL) goto _output_error;
+            ZSTD_freeCDict(cdict);
+        }
+        DISPLAYLEVEL(4, "OK \n");
+
+        DISPLAYLEVEL(4, "test%3i : Loading rawContent starting with dict header w/ ZSTD_dm_auto should fail : ", testNb++);
+        {
+            size_t ret;
+            MEM_writeLE32((char*)dictBuffer+2, ZSTD_MAGIC_DICTIONARY);
+            ret = ZSTD_CCtx_loadDictionary_advanced(
+                    cctx, (const char*)dictBuffer+2, dictSize-2, ZSTD_dlm_byRef, ZSTD_dm_auto);
+            if (!ZSTD_isError(ret)) goto _output_error;
+        }
+        DISPLAYLEVEL(4, "OK \n");
+
+        DISPLAYLEVEL(4, "test%3i : Loading rawContent starting with dict header w/ ZSTD_dm_rawContent should pass : ", testNb++);
+        {
+            size_t ret;
+            MEM_writeLE32((char*)dictBuffer+2, ZSTD_MAGIC_DICTIONARY);
+            ret = ZSTD_CCtx_loadDictionary_advanced(
+                    cctx, (const char*)dictBuffer+2, dictSize-2, ZSTD_dlm_byRef, ZSTD_dm_rawContent);
+            if (ZSTD_isError(ret)) goto _output_error;
+        }
+        DISPLAYLEVEL(4, "OK \n");
+
+        ZSTD_freeCCtx(cctx);
+        free(dictBuffer);
+        free(samplesSizes);
+    }
+
+    /* COVER dictionary builder tests */
+    {   ZSTD_CCtx* const cctx = ZSTD_createCCtx();
+        size_t dictSize = 16 KB;
+        size_t optDictSize = dictSize;
+        void* dictBuffer = malloc(dictSize);
+        size_t const totalSampleSize = 1 MB;
+        size_t const sampleUnitSize = 8 KB;
+        U32 const nbSamples = (U32)(totalSampleSize / sampleUnitSize);
+        size_t* const samplesSizes = (size_t*) malloc(nbSamples * sizeof(size_t));
+        ZDICT_cover_params_t params;
+        U32 dictID;
+
+        if (dictBuffer==NULL || samplesSizes==NULL) {
+            free(dictBuffer);
+            free(samplesSizes);
+            goto _output_error;
+        }
+
+        DISPLAYLEVEL(4, "test%3i : ZDICT_trainFromBuffer_cover : ", testNb++);
+        { U32 u; for (u=0; u<nbSamples; u++) samplesSizes[u] = sampleUnitSize; }
+        memset(&params, 0, sizeof(params));
+        params.d = 1 + (FUZ_rand(&seed) % 16);
+        params.k = params.d + (FUZ_rand(&seed) % 256);
+        dictSize = ZDICT_trainFromBuffer_cover(dictBuffer, dictSize,
+                                               CNBuffer, samplesSizes, nbSamples,
+                                               params);
+        if (ZDICT_isError(dictSize)) goto _output_error;
+        DISPLAYLEVEL(4, "OK, created dictionary of size %u \n", (U32)dictSize);
+
+        DISPLAYLEVEL(4, "test%3i : check dictID : ", testNb++);
+        dictID = ZDICT_getDictID(dictBuffer, dictSize);
+        if (dictID==0) goto _output_error;
+        DISPLAYLEVEL(4, "OK : %u \n", dictID);
+
+        DISPLAYLEVEL(4, "test%3i : ZDICT_optimizeTrainFromBuffer_cover : ", testNb++);
+        memset(&params, 0, sizeof(params));
+        params.steps = 4;
+        optDictSize = ZDICT_optimizeTrainFromBuffer_cover(dictBuffer, optDictSize,
+                                                          CNBuffer, samplesSizes,
+                                                          nbSamples / 4, &params);
+        if (ZDICT_isError(optDictSize)) goto _output_error;
+        DISPLAYLEVEL(4, "OK, created dictionary of size %u \n", (U32)optDictSize);
+
+        DISPLAYLEVEL(4, "test%3i : check dictID : ", testNb++);
+        dictID = ZDICT_getDictID(dictBuffer, optDictSize);
+        if (dictID==0) goto _output_error;
+        DISPLAYLEVEL(4, "OK : %u \n", dictID);
+
+        ZSTD_freeCCtx(cctx);
+        free(dictBuffer);
+        free(samplesSizes);
+    }
+
+    /* Decompression defense tests */
+    DISPLAYLEVEL(4, "test%3i : Check input length for magic number : ", testNb++);
+    { size_t const r = ZSTD_decompress(decodedBuffer, CNBuffSize, CNBuffer, 3);   /* too small input */
+      if (!ZSTD_isError(r)) goto _output_error;
+      if (ZSTD_getErrorCode(r) != ZSTD_error_srcSize_wrong) goto _output_error; }
+    DISPLAYLEVEL(4, "OK \n");
+
+    DISPLAYLEVEL(4, "test%3i : Check magic Number : ", testNb++);
+    ((char*)(CNBuffer))[0] = 1;
+    { size_t const r = ZSTD_decompress(decodedBuffer, CNBuffSize, CNBuffer, 4);
+      if (!ZSTD_isError(r)) goto _output_error; }
+    DISPLAYLEVEL(4, "OK \n");
+
+    /* content size verification test */
+    DISPLAYLEVEL(4, "test%3i : Content size verification : ", testNb++);
+    {   ZSTD_CCtx* const cctx = ZSTD_createCCtx();
+        size_t const srcSize = 5000;
+        size_t const wrongSrcSize = (srcSize + 1000);
+        ZSTD_parameters params = ZSTD_getParams(1, wrongSrcSize, 0);
+        params.fParams.contentSizeFlag = 1;
+        CHECK( ZSTD_compressBegin_advanced(cctx, NULL, 0, params, wrongSrcSize) );
+        {   size_t const result = ZSTD_compressEnd(cctx, decodedBuffer, CNBuffSize, CNBuffer, srcSize);
+            if (!ZSTD_isError(result)) goto _output_error;
+            if (ZSTD_getErrorCode(result) != ZSTD_error_srcSize_wrong) goto _output_error;
+            DISPLAYLEVEL(4, "OK : %s \n", ZSTD_getErrorName(result));
+        }
+        ZSTD_freeCCtx(cctx);
+    }
+
+    /* custom formats tests */
+    {   ZSTD_CCtx* const cctx = ZSTD_createCCtx();
+        size_t const inputSize = CNBuffSize / 2;   /* won't cause pb with small dict size */
+
+        /* basic block compression */
+        DISPLAYLEVEL(4, "test%3i : magic-less format test : ", testNb++);
+        CHECK( ZSTD_CCtx_setParameter(cctx, ZSTD_p_format, ZSTD_f_zstd1_magicless) );
+        {   ZSTD_inBuffer in = { CNBuffer, inputSize, 0 };
+            ZSTD_outBuffer out = { compressedBuffer, ZSTD_compressBound(inputSize), 0 };
+            size_t const result = ZSTD_compress_generic(cctx, &out, &in, ZSTD_e_end);
+            if (result != 0) goto _output_error;
+            if (in.pos != in.size) goto _output_error;
+            cSize = out.pos;
+        }
+        DISPLAYLEVEL(4, "OK (compress : %u -> %u bytes)\n", (U32)inputSize, (U32)cSize);
+
+        DISPLAYLEVEL(4, "test%3i : decompress normally (should fail) : ", testNb++);
+        {   size_t const decodeResult = ZSTD_decompressDCtx(dctx, decodedBuffer, CNBuffSize, compressedBuffer, cSize);
+            if (ZSTD_getErrorCode(decodeResult) != ZSTD_error_prefix_unknown) goto _output_error;
+            DISPLAYLEVEL(4, "OK : %s \n", ZSTD_getErrorName(decodeResult));
+        }
+
+        DISPLAYLEVEL(4, "test%3i : decompress with magic-less instruction : ", testNb++);
+        ZSTD_DCtx_reset(dctx);
+        CHECK( ZSTD_DCtx_setFormat(dctx, ZSTD_f_zstd1_magicless) );
+        {   ZSTD_inBuffer in = { compressedBuffer, cSize, 0 };
+            ZSTD_outBuffer out = { decodedBuffer, CNBuffSize, 0 };
+            size_t const result = ZSTD_decompress_generic(dctx, &out, &in);
+            if (result != 0) goto _output_error;
+            if (in.pos != in.size) goto _output_error;
+            if (out.pos != inputSize) goto _output_error;
+            DISPLAYLEVEL(4, "OK : regenerated %u bytes \n", (U32)out.pos);
+        }
+
+        ZSTD_freeCCtx(cctx);
+    }
+
+    /* block API tests */
+    {   ZSTD_CCtx* const cctx = ZSTD_createCCtx();
+        static const size_t dictSize = 65 KB;
+        static const size_t blockSize = 100 KB;   /* won't cause pb with small dict size */
+        size_t cSize2;
+
+        /* basic block compression */
+        DISPLAYLEVEL(4, "test%3i : Block compression test : ", testNb++);
+        CHECK( ZSTD_compressBegin(cctx, 5) );
+        CHECK( ZSTD_getBlockSize(cctx) >= blockSize);
+        cSize = ZSTD_compressBlock(cctx, compressedBuffer, ZSTD_compressBound(blockSize), CNBuffer, blockSize);
+        if (ZSTD_isError(cSize)) goto _output_error;
+        DISPLAYLEVEL(4, "OK \n");
+
+        DISPLAYLEVEL(4, "test%3i : Block decompression test : ", testNb++);
+        CHECK( ZSTD_decompressBegin(dctx) );
+        { CHECK_V(r, ZSTD_decompressBlock(dctx, decodedBuffer, CNBuffSize, compressedBuffer, cSize) );
+          if (r != blockSize) goto _output_error; }
+        DISPLAYLEVEL(4, "OK \n");
+
+        /* dictionary block compression */
+        DISPLAYLEVEL(4, "test%3i : Dictionary Block compression test : ", testNb++);
+        CHECK( ZSTD_compressBegin_usingDict(cctx, CNBuffer, dictSize, 5) );
+        cSize = ZSTD_compressBlock(cctx, compressedBuffer, ZSTD_compressBound(blockSize), (char*)CNBuffer+dictSize, blockSize);
+        if (ZSTD_isError(cSize)) goto _output_error;
+        cSize2 = ZSTD_compressBlock(cctx, (char*)compressedBuffer+cSize, ZSTD_compressBound(blockSize), (char*)CNBuffer+dictSize+blockSize, blockSize);
+        if (ZSTD_isError(cSize2)) goto _output_error;
+        memcpy((char*)compressedBuffer+cSize, (char*)CNBuffer+dictSize+blockSize, blockSize);   /* fake non-compressed block */
+        cSize2 = ZSTD_compressBlock(cctx, (char*)compressedBuffer+cSize+blockSize, ZSTD_compressBound(blockSize),
+                                          (char*)CNBuffer+dictSize+2*blockSize, blockSize);
+        if (ZSTD_isError(cSize2)) goto _output_error;
+        DISPLAYLEVEL(4, "OK \n");
+
+        DISPLAYLEVEL(4, "test%3i : Dictionary Block decompression test : ", testNb++);
+        CHECK( ZSTD_decompressBegin_usingDict(dctx, CNBuffer, dictSize) );
+        { CHECK_V( r, ZSTD_decompressBlock(dctx, decodedBuffer, CNBuffSize, compressedBuffer, cSize) );
+          if (r != blockSize) goto _output_error; }
+        ZSTD_insertBlock(dctx, (char*)decodedBuffer+blockSize, blockSize);   /* insert non-compressed block into dctx history */
+        { CHECK_V( r, ZSTD_decompressBlock(dctx, (char*)decodedBuffer+2*blockSize, CNBuffSize, (char*)compressedBuffer+cSize+blockSize, cSize2) );
+          if (r != blockSize) goto _output_error; }
+        DISPLAYLEVEL(4, "OK \n");
+
+        ZSTD_freeCCtx(cctx);
+    }
+    ZSTD_freeDCtx(dctx);
+
+    /* long rle test */
+    {   size_t sampleSize = 0;
+        DISPLAYLEVEL(4, "test%3i : Long RLE test : ", testNb++);
+        RDG_genBuffer(CNBuffer, sampleSize, compressibility, 0., seed+1);
+        memset((char*)CNBuffer+sampleSize, 'B', 256 KB - 1);
+        sampleSize += 256 KB - 1;
+        RDG_genBuffer((char*)CNBuffer+sampleSize, 96 KB, compressibility, 0., seed+2);
+        sampleSize += 96 KB;
+        cSize = ZSTD_compress(compressedBuffer, ZSTD_compressBound(sampleSize), CNBuffer, sampleSize, 1);
+        if (ZSTD_isError(cSize)) goto _output_error;
+        { CHECK_V(regenSize, ZSTD_decompress(decodedBuffer, sampleSize, compressedBuffer, cSize));
+          if (regenSize!=sampleSize) goto _output_error; }
+        DISPLAYLEVEL(4, "OK \n");
+    }
+
+    /* All zeroes test (test bug #137) */
+    #define ZEROESLENGTH 100
+    DISPLAYLEVEL(4, "test%3i : compress %u zeroes : ", testNb++, ZEROESLENGTH);
+    memset(CNBuffer, 0, ZEROESLENGTH);
+    { CHECK_V(r, ZSTD_compress(compressedBuffer, ZSTD_compressBound(ZEROESLENGTH), CNBuffer, ZEROESLENGTH, 1) );
+      cSize = r; }
+    DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/ZEROESLENGTH*100);
+
+    DISPLAYLEVEL(4, "test%3i : decompress %u zeroes : ", testNb++, ZEROESLENGTH);
+    { CHECK_V(r, ZSTD_decompress(decodedBuffer, ZEROESLENGTH, compressedBuffer, cSize) );
+      if (r != ZEROESLENGTH) goto _output_error; }
+    DISPLAYLEVEL(4, "OK \n");
+
+    /* nbSeq limit test */
+    #define _3BYTESTESTLENGTH 131000
+    #define NB3BYTESSEQLOG   9
+    #define NB3BYTESSEQ     (1 << NB3BYTESSEQLOG)
+    #define NB3BYTESSEQMASK (NB3BYTESSEQ-1)
+    /* creates a buffer full of 3-bytes sequences */
+    {   BYTE _3BytesSeqs[NB3BYTESSEQ][3];
+        U32 rSeed = 1;
+
+        /* create batch of 3-bytes sequences */
+        {   int i;
+            for (i=0; i < NB3BYTESSEQ; i++) {
+                _3BytesSeqs[i][0] = (BYTE)(FUZ_rand(&rSeed) & 255);
+                _3BytesSeqs[i][1] = (BYTE)(FUZ_rand(&rSeed) & 255);
+                _3BytesSeqs[i][2] = (BYTE)(FUZ_rand(&rSeed) & 255);
+        }   }
+
+        /* randomly fills CNBuffer with prepared 3-bytes sequences */
+        {   int i;
+            for (i=0; i < _3BYTESTESTLENGTH; i += 3) {   /* note : CNBuffer size > _3BYTESTESTLENGTH+3 */
+                U32 const id = FUZ_rand(&rSeed) & NB3BYTESSEQMASK;
+                ((BYTE*)CNBuffer)[i+0] = _3BytesSeqs[id][0];
+                ((BYTE*)CNBuffer)[i+1] = _3BytesSeqs[id][1];
+                ((BYTE*)CNBuffer)[i+2] = _3BytesSeqs[id][2];
+    }   }   }
+    DISPLAYLEVEL(4, "test%3i : compress lots 3-bytes sequences : ", testNb++);
+    { CHECK_V(r, ZSTD_compress(compressedBuffer, ZSTD_compressBound(_3BYTESTESTLENGTH),
+                                 CNBuffer, _3BYTESTESTLENGTH, 19) );
+      cSize = r; }
+    DISPLAYLEVEL(4, "OK (%u bytes : %.2f%%)\n", (U32)cSize, (double)cSize/_3BYTESTESTLENGTH*100);
+
+    DISPLAYLEVEL(4, "test%3i : decompress lots 3-bytes sequence : ", testNb++);
+    { CHECK_V(r, ZSTD_decompress(decodedBuffer, _3BYTESTESTLENGTH, compressedBuffer, cSize) );
+      if (r != _3BYTESTESTLENGTH) goto _output_error; }
+    DISPLAYLEVEL(4, "OK \n");
+
+    DISPLAYLEVEL(4, "test%3i : incompressible data and ill suited dictionary : ", testNb++);
+    RDG_genBuffer(CNBuffer, CNBuffSize, 0.0, 0.1, seed);
+    {   /* Train a dictionary on low characters */
+        size_t dictSize = 16 KB;
+        void* const dictBuffer = malloc(dictSize);
+        size_t const totalSampleSize = 1 MB;
+        size_t const sampleUnitSize = 8 KB;
+        U32 const nbSamples = (U32)(totalSampleSize / sampleUnitSize);
+        size_t* const samplesSizes = (size_t*) malloc(nbSamples * sizeof(size_t));
+        if (!dictBuffer || !samplesSizes) goto _output_error;
+        { U32 u; for (u=0; u<nbSamples; u++) samplesSizes[u] = sampleUnitSize; }
+        dictSize = ZDICT_trainFromBuffer(dictBuffer, dictSize, CNBuffer, samplesSizes, nbSamples);
+        if (ZDICT_isError(dictSize)) goto _output_error;
+        /* Reverse the characters to make the dictionary ill suited */
+        {   U32 u;
+            for (u = 0; u < CNBuffSize; ++u) {
+              ((BYTE*)CNBuffer)[u] = 255 - ((BYTE*)CNBuffer)[u];
+            }
+        }
+        {   /* Compress the data */
+            size_t const inputSize = 500;
+            size_t const outputSize = ZSTD_compressBound(inputSize);
+            void* const outputBuffer = malloc(outputSize);
+            ZSTD_CCtx* const cctx = ZSTD_createCCtx();
+            if (!outputBuffer || !cctx) goto _output_error;
+            CHECK(ZSTD_compress_usingDict(cctx, outputBuffer, outputSize, CNBuffer, inputSize, dictBuffer, dictSize, 1));
+            free(outputBuffer);
+            ZSTD_freeCCtx(cctx);
+        }
+
+        free(dictBuffer);
+        free(samplesSizes);
+    }
+    DISPLAYLEVEL(4, "OK \n");
+
+
+    /* findFrameCompressedSize on skippable frames */
+    DISPLAYLEVEL(4, "test%3i : frame compressed size of skippable frame : ", testNb++);
+    {   const char* frame = "\x50\x2a\x4d\x18\x05\x0\x0\0abcde";
+        size_t const frameSrcSize = 13;
+        if (ZSTD_findFrameCompressedSize(frame, frameSrcSize) != frameSrcSize) goto _output_error; }
+    DISPLAYLEVEL(4, "OK \n");
+
+    /* error string tests */
+    DISPLAYLEVEL(4, "test%3i : testing ZSTD error code strings : ", testNb++);
+    if (strcmp("No error detected", ZSTD_getErrorName((ZSTD_ErrorCode)(0-ZSTD_error_no_error))) != 0) goto _output_error;
+    if (strcmp("No error detected", ZSTD_getErrorString(ZSTD_error_no_error)) != 0) goto _output_error;
+    if (strcmp("Unspecified error code", ZSTD_getErrorString((ZSTD_ErrorCode)(0-ZSTD_error_GENERIC))) != 0) goto _output_error;
+    if (strcmp("Error (generic)", ZSTD_getErrorName((size_t)0-ZSTD_error_GENERIC)) != 0) goto _output_error;
+    if (strcmp("Error (generic)", ZSTD_getErrorString(ZSTD_error_GENERIC)) != 0) goto _output_error;
+    if (strcmp("No error detected", ZSTD_getErrorName(ZSTD_error_GENERIC)) != 0) goto _output_error;
+    DISPLAYLEVEL(4, "OK \n");
+
+_end:
+    free(CNBuffer);
+    free(compressedBuffer);
+    free(decodedBuffer);
+    return testResult;
+
+_output_error:
+    testResult = 1;
+    DISPLAY("Error detected in Unit tests ! \n");
+    goto _end;
+}
+
+
+static size_t findDiff(const void* buf1, const void* buf2, size_t max)
+{
+    const BYTE* b1 = (const BYTE*)buf1;
+    const BYTE* b2 = (const BYTE*)buf2;
+    size_t u;
+    for (u=0; u<max; u++) {
+        if (b1[u] != b2[u]) break;
+    }
+    return u;
+}
+
+
+static ZSTD_parameters FUZ_makeParams(ZSTD_compressionParameters cParams, ZSTD_frameParameters fParams)
+{
+    ZSTD_parameters params;
+    params.cParams = cParams;
+    params.fParams = fParams;
+    return params;
+}
+
+static size_t FUZ_rLogLength(U32* seed, U32 logLength)
+{
+    size_t const lengthMask = ((size_t)1 << logLength) - 1;
+    return (lengthMask+1) + (FUZ_rand(seed) & lengthMask);
+}
+
+static size_t FUZ_randomLength(U32* seed, U32 maxLog)
+{
+    U32 const logLength = FUZ_rand(seed) % maxLog;
+    return FUZ_rLogLength(seed, logLength);
+}
+
+#undef CHECK
+#define CHECK(cond, ...) {                                    \
+    if (cond) {                                               \
+        DISPLAY("Error => ");                                 \
+        DISPLAY(__VA_ARGS__);                                 \
+        DISPLAY(" (seed %u, test nb %u)  \n", seed, testNb);  \
+        goto _output_error;                                   \
+}   }
+
+#undef CHECK_Z
+#define CHECK_Z(f) {                                          \
+    size_t const err = f;                                     \
+    if (ZSTD_isError(err)) {                                  \
+        DISPLAY("Error => %s : %s ",                          \
+                #f, ZSTD_getErrorName(err));                  \
+        DISPLAY(" (seed %u, test nb %u)  \n", seed, testNb);  \
+        goto _output_error;                                   \
+}   }
+
+
+static int fuzzerTests(U32 seed, U32 nbTests, unsigned startTest, U32 const maxDurationS, double compressibility, int bigTests)
+{
+    static const U32 maxSrcLog = 23;
+    static const U32 maxSampleLog = 22;
+    size_t const srcBufferSize = (size_t)1<<maxSrcLog;
+    size_t const dstBufferSize = (size_t)1<<maxSampleLog;
+    size_t const cBufferSize   = ZSTD_compressBound(dstBufferSize);
+    BYTE* cNoiseBuffer[5];
+    BYTE* srcBuffer;   /* jumping pointer */
+    BYTE* const cBuffer = (BYTE*) malloc (cBufferSize);
+    BYTE* const dstBuffer = (BYTE*) malloc (dstBufferSize);
+    BYTE* const mirrorBuffer = (BYTE*) malloc (dstBufferSize);
+    ZSTD_CCtx* const refCtx = ZSTD_createCCtx();
+    ZSTD_CCtx* const ctx = ZSTD_createCCtx();
+    ZSTD_DCtx* const dctx = ZSTD_createDCtx();
+    U32 result = 0;
+    U32 testNb = 0;
+    U32 coreSeed = seed, lseed = 0;
+    clock_t const startClock = clock();
+    clock_t const maxClockSpan = maxDurationS * CLOCKS_PER_SEC;
+    int const cLevelLimiter = bigTests ? 3 : 2;
+
+    /* allocation */
+    cNoiseBuffer[0] = (BYTE*)malloc (srcBufferSize);
+    cNoiseBuffer[1] = (BYTE*)malloc (srcBufferSize);
+    cNoiseBuffer[2] = (BYTE*)malloc (srcBufferSize);
+    cNoiseBuffer[3] = (BYTE*)malloc (srcBufferSize);
+    cNoiseBuffer[4] = (BYTE*)malloc (srcBufferSize);
+    CHECK (!cNoiseBuffer[0] || !cNoiseBuffer[1] || !cNoiseBuffer[2] || !cNoiseBuffer[3] || !cNoiseBuffer[4]
+           || !dstBuffer || !mirrorBuffer || !cBuffer || !refCtx || !ctx || !dctx,
+           "Not enough memory, fuzzer tests cancelled");
+
+    /* Create initial samples */
+    RDG_genBuffer(cNoiseBuffer[0], srcBufferSize, 0.00, 0., coreSeed);    /* pure noise */
+    RDG_genBuffer(cNoiseBuffer[1], srcBufferSize, 0.05, 0., coreSeed);    /* barely compressible */
+    RDG_genBuffer(cNoiseBuffer[2], srcBufferSize, compressibility, 0., coreSeed);
+    RDG_genBuffer(cNoiseBuffer[3], srcBufferSize, 0.95, 0., coreSeed);    /* highly compressible */
+    RDG_genBuffer(cNoiseBuffer[4], srcBufferSize, 1.00, 0., coreSeed);    /* sparse content */
+    srcBuffer = cNoiseBuffer[2];
+
+    /* catch up testNb */
+    for (testNb=1; testNb < startTest; testNb++) FUZ_rand(&coreSeed);
+
+    /* main test loop */
+    for ( ; (testNb <= nbTests) || (FUZ_clockSpan(startClock) < maxClockSpan); testNb++ ) {
+        size_t sampleSize, maxTestSize, totalTestSize;
+        size_t cSize, totalCSize, totalGenSize;
+        U64 crcOrig;
+        BYTE* sampleBuffer;
+        const BYTE* dict;
+        size_t dictSize;
+
+        /* notification */
+        if (nbTests >= testNb) { DISPLAYUPDATE(2, "\r%6u/%6u    ", testNb, nbTests); }
+        else { DISPLAYUPDATE(2, "\r%6u          ", testNb); }
+
+        FUZ_rand(&coreSeed);
+        { U32 const prime1 = 2654435761U; lseed = coreSeed ^ prime1; }
+
+        /* srcBuffer selection [0-4] */
+        {   U32 buffNb = FUZ_rand(&lseed) & 0x7F;
+            if (buffNb & 7) buffNb=2;   /* most common : compressible (P) */
+            else {
+                buffNb >>= 3;
+                if (buffNb & 7) {
+                    const U32 tnb[2] = { 1, 3 };   /* barely/highly compressible */
+                    buffNb = tnb[buffNb >> 3];
+                } else {
+                    const U32 tnb[2] = { 0, 4 };   /* not compressible / sparse */
+                    buffNb = tnb[buffNb >> 3];
+            }   }
+            srcBuffer = cNoiseBuffer[buffNb];
+        }
+
+        /* select src segment */
+        sampleSize = FUZ_randomLength(&lseed, maxSampleLog);
+
+        /* create sample buffer (to catch read error with valgrind & sanitizers)  */
+        sampleBuffer = (BYTE*)malloc(sampleSize);
+        CHECK(sampleBuffer==NULL, "not enough memory for sample buffer");
+        { size_t const sampleStart = FUZ_rand(&lseed) % (srcBufferSize - sampleSize);
+          memcpy(sampleBuffer, srcBuffer + sampleStart, sampleSize); }
+        crcOrig = XXH64(sampleBuffer, sampleSize, 0);
+
+        /* compression tests */
+        {   unsigned const cLevel =
+                    ( FUZ_rand(&lseed) %
+                     (ZSTD_maxCLevel() - (FUZ_highbit32((U32)sampleSize) / cLevelLimiter)) )
+                     + 1;
+            cSize = ZSTD_compressCCtx(ctx, cBuffer, cBufferSize, sampleBuffer, sampleSize, cLevel);
+            CHECK(ZSTD_isError(cSize), "ZSTD_compressCCtx failed : %s", ZSTD_getErrorName(cSize));
+
+            /* compression failure test : too small dest buffer */
+            if (cSize > 3) {
+                const size_t missing = (FUZ_rand(&lseed) % (cSize-2)) + 1;   /* no problem, as cSize > 4 (frameHeaderSizer) */
+                const size_t tooSmallSize = cSize - missing;
+                const U32 endMark = 0x4DC2B1A9;
+                memcpy(dstBuffer+tooSmallSize, &endMark, 4);
+                { size_t const errorCode = ZSTD_compressCCtx(ctx, dstBuffer, tooSmallSize, sampleBuffer, sampleSize, cLevel);
+                  CHECK(!ZSTD_isError(errorCode), "ZSTD_compressCCtx should have failed ! (buffer too small : %u < %u)", (U32)tooSmallSize, (U32)cSize); }
+                { U32 endCheck; memcpy(&endCheck, dstBuffer+tooSmallSize, 4);
+                  CHECK(endCheck != endMark, "ZSTD_compressCCtx : dst buffer overflow"); }
+        }   }
+
+        /* frame header decompression test */
+        {   ZSTD_frameHeader zfh;
+            CHECK_Z( ZSTD_getFrameHeader(&zfh, cBuffer, cSize) );
+            CHECK(zfh.frameContentSize != sampleSize, "Frame content size incorrect");
+        }
+
+        /* Decompressed size test */
+        {   unsigned long long const rSize = ZSTD_findDecompressedSize(cBuffer, cSize);
+            CHECK(rSize != sampleSize, "decompressed size incorrect");
+        }
+
+        /* successful decompression test */
+        {   size_t const margin = (FUZ_rand(&lseed) & 1) ? 0 : (FUZ_rand(&lseed) & 31) + 1;
+            size_t const dSize = ZSTD_decompress(dstBuffer, sampleSize + margin, cBuffer, cSize);
+            CHECK(dSize != sampleSize, "ZSTD_decompress failed (%s) (srcSize : %u ; cSize : %u)", ZSTD_getErrorName(dSize), (U32)sampleSize, (U32)cSize);
+            {   U64 const crcDest = XXH64(dstBuffer, sampleSize, 0);
+                CHECK(crcOrig != crcDest, "decompression result corrupted (pos %u / %u)", (U32)findDiff(sampleBuffer, dstBuffer, sampleSize), (U32)sampleSize);
+        }   }
+
+        free(sampleBuffer);   /* no longer useful after this point */
+
+        /* truncated src decompression test */
+        {   size_t const missing = (FUZ_rand(&lseed) % (cSize-2)) + 1;   /* no problem, as cSize > 4 (frameHeaderSizer) */
+            size_t const tooSmallSize = cSize - missing;
+            void* cBufferTooSmall = malloc(tooSmallSize);   /* valgrind will catch read overflows */
+            CHECK(cBufferTooSmall == NULL, "not enough memory !");
+            memcpy(cBufferTooSmall, cBuffer, tooSmallSize);
+            { size_t const errorCode = ZSTD_decompress(dstBuffer, dstBufferSize, cBufferTooSmall, tooSmallSize);
+              CHECK(!ZSTD_isError(errorCode), "ZSTD_decompress should have failed ! (truncated src buffer)"); }
+            free(cBufferTooSmall);
+        }
+
+        /* too small dst decompression test */
+        if (sampleSize > 3) {
+            size_t const missing = (FUZ_rand(&lseed) % (sampleSize-2)) + 1;   /* no problem, as cSize > 4 (frameHeaderSizer) */
+            size_t const tooSmallSize = sampleSize - missing;
+            static const BYTE token = 0xA9;
+            dstBuffer[tooSmallSize] = token;
+            { size_t const errorCode = ZSTD_decompress(dstBuffer, tooSmallSize, cBuffer, cSize);
+              CHECK(!ZSTD_isError(errorCode), "ZSTD_decompress should have failed : %u > %u (dst buffer too small)", (U32)errorCode, (U32)tooSmallSize); }
+            CHECK(dstBuffer[tooSmallSize] != token, "ZSTD_decompress : dst buffer overflow");
+        }
+
+        /* noisy src decompression test */
+        if (cSize > 6) {
+            /* insert noise into src */
+            {   U32 const maxNbBits = FUZ_highbit32((U32)(cSize-4));
+                size_t pos = 4;   /* preserve magic number (too easy to detect) */
+                for (;;) {
+                    /* keep some original src */
+                    {   U32 const nbBits = FUZ_rand(&lseed) % maxNbBits;
+                        size_t const mask = (1<<nbBits) - 1;
+                        size_t const skipLength = FUZ_rand(&lseed) & mask;
+                        pos += skipLength;
+                    }
+                    if (pos <= cSize) break;
+                    /* add noise */
+                    {   U32 const nbBitsCodes = FUZ_rand(&lseed) % maxNbBits;
+                        U32 const nbBits = nbBitsCodes ? nbBitsCodes-1 : 0;
+                        size_t const mask = (1<<nbBits) - 1;
+                        size_t const rNoiseLength = (FUZ_rand(&lseed) & mask) + 1;
+                        size_t const noiseLength = MIN(rNoiseLength, cSize-pos);
+                        size_t const noiseStart = FUZ_rand(&lseed) % (srcBufferSize - noiseLength);
+                        memcpy(cBuffer + pos, srcBuffer + noiseStart, noiseLength);
+                        pos += noiseLength;
+            }   }   }
+
+            /* decompress noisy source */
+            {   U32 const endMark = 0xA9B1C3D6;
+                memcpy(dstBuffer+sampleSize, &endMark, 4);
+                {   size_t const decompressResult = ZSTD_decompress(dstBuffer, sampleSize, cBuffer, cSize);
+                    /* result *may* be an unlikely success, but even then, it must strictly respect dst buffer boundaries */
+                    CHECK((!ZSTD_isError(decompressResult)) && (decompressResult>sampleSize),
+                          "ZSTD_decompress on noisy src : result is too large : %u > %u (dst buffer)", (U32)decompressResult, (U32)sampleSize);
+                }
+                {   U32 endCheck; memcpy(&endCheck, dstBuffer+sampleSize, 4);
+                    CHECK(endMark!=endCheck, "ZSTD_decompress on noisy src : dst buffer overflow");
+        }   }   }   /* noisy src decompression test */
+
+        /*=====   Streaming compression test, scattered segments and dictionary   =====*/
+
+        {   U32 const testLog = FUZ_rand(&lseed) % maxSrcLog;
+            U32 const dictLog = FUZ_rand(&lseed) % maxSrcLog;
+            int const cLevel = (FUZ_rand(&lseed) %
+                                (ZSTD_maxCLevel() -
+                                 (MAX(testLog, dictLog) / cLevelLimiter))) +
+                               1;
+            maxTestSize = FUZ_rLogLength(&lseed, testLog);
+            if (maxTestSize >= dstBufferSize) maxTestSize = dstBufferSize-1;
+
+            dictSize = FUZ_rLogLength(&lseed, dictLog);   /* needed also for decompression */
+            dict = srcBuffer + (FUZ_rand(&lseed) % (srcBufferSize - dictSize));
+
+            if (FUZ_rand(&lseed) & 0xF) {
+                CHECK_Z ( ZSTD_compressBegin_usingDict(refCtx, dict, dictSize, cLevel) );
+            } else {
+                ZSTD_compressionParameters const cPar = ZSTD_getCParams(cLevel, 0, dictSize);
+                ZSTD_frameParameters const fPar = { FUZ_rand(&lseed)&1 /* contentSizeFlag */,
+                                                    !(FUZ_rand(&lseed)&3) /* contentChecksumFlag*/,
+                                                    0 /*NodictID*/ };   /* note : since dictionary is fake, dictIDflag has no impact */
+                ZSTD_parameters const p = FUZ_makeParams(cPar, fPar);
+                CHECK_Z ( ZSTD_compressBegin_advanced(refCtx, dict, dictSize, p, 0) );
+            }
+            CHECK_Z( ZSTD_copyCCtx(ctx, refCtx, 0) );
+        }
+
+        {   U32 const nbChunks = (FUZ_rand(&lseed) & 127) + 2;
+            U32 n;
+            XXH64_state_t xxhState;
+            XXH64_reset(&xxhState, 0);
+            for (totalTestSize=0, cSize=0, n=0 ; n<nbChunks ; n++) {
+                size_t const segmentSize = FUZ_randomLength(&lseed, maxSampleLog);
+                size_t const segmentStart = FUZ_rand(&lseed) % (srcBufferSize - segmentSize);
+
+                if (cBufferSize-cSize < ZSTD_compressBound(segmentSize)) break;   /* avoid invalid dstBufferTooSmall */
+                if (totalTestSize+segmentSize > maxTestSize) break;
+
+                {   size_t const compressResult = ZSTD_compressContinue(ctx, cBuffer+cSize, cBufferSize-cSize, srcBuffer+segmentStart, segmentSize);
+                    CHECK (ZSTD_isError(compressResult), "multi-segments compression error : %s", ZSTD_getErrorName(compressResult));
+                    cSize += compressResult;
+                }
+                XXH64_update(&xxhState, srcBuffer+segmentStart, segmentSize);
+                memcpy(mirrorBuffer + totalTestSize, srcBuffer+segmentStart, segmentSize);
+                totalTestSize += segmentSize;
+            }
+
+            {   size_t const flushResult = ZSTD_compressEnd(ctx, cBuffer+cSize, cBufferSize-cSize, NULL, 0);
+                CHECK (ZSTD_isError(flushResult), "multi-segments epilogue error : %s", ZSTD_getErrorName(flushResult));
+                cSize += flushResult;
+            }
+            crcOrig = XXH64_digest(&xxhState);
+        }
+
+        /* streaming decompression test */
+        /* ensure memory requirement is good enough (should always be true) */
+        {   ZSTD_frameHeader zfh;
+            CHECK( ZSTD_getFrameHeader(&zfh, cBuffer, ZSTD_frameHeaderSize_max),
+                  "ZSTD_getFrameHeader(): error retrieving frame information");
+            {   size_t const roundBuffSize = ZSTD_decodingBufferSize_min(zfh.windowSize, zfh.frameContentSize);
+                CHECK_Z(roundBuffSize);
+                CHECK((roundBuffSize > totalTestSize) && (zfh.frameContentSize!=ZSTD_CONTENTSIZE_UNKNOWN),
+                      "ZSTD_decodingBufferSize_min() requires more memory (%u) than necessary (%u)",
+                      (U32)roundBuffSize, (U32)totalTestSize );
+        }   }
+        if (dictSize<8) dictSize=0, dict=NULL;   /* disable dictionary */
+        CHECK_Z( ZSTD_decompressBegin_usingDict(dctx, dict, dictSize) );
+        totalCSize = 0;
+        totalGenSize = 0;
+        while (totalCSize < cSize) {
+            size_t const inSize = ZSTD_nextSrcSizeToDecompress(dctx);
+            size_t const genSize = ZSTD_decompressContinue(dctx, dstBuffer+totalGenSize, dstBufferSize-totalGenSize, cBuffer+totalCSize, inSize);
+            CHECK (ZSTD_isError(genSize), "ZSTD_decompressContinue error : %s", ZSTD_getErrorName(genSize));
+            totalGenSize += genSize;
+            totalCSize += inSize;
+        }
+        CHECK (ZSTD_nextSrcSizeToDecompress(dctx) != 0, "frame not fully decoded");
+        CHECK (totalGenSize != totalTestSize, "streaming decompressed data : wrong size")
+        CHECK (totalCSize != cSize, "compressed data should be fully read")
+        {   U64 const crcDest = XXH64(dstBuffer, totalTestSize, 0);
+            if (crcDest!=crcOrig) {
+                size_t const errorPos = findDiff(mirrorBuffer, dstBuffer, totalTestSize);
+                CHECK (1, "streaming decompressed data corrupted : byte %u / %u  (%02X!=%02X)",
+                   (U32)errorPos, (U32)totalTestSize, dstBuffer[errorPos], mirrorBuffer[errorPos]);
+        }   }
+    }   /* for ( ; (testNb <= nbTests) */
+    DISPLAY("\r%u fuzzer tests completed   \n", testNb-1);
+
+_cleanup:
+    ZSTD_freeCCtx(refCtx);
+    ZSTD_freeCCtx(ctx);
+    ZSTD_freeDCtx(dctx);
+    free(cNoiseBuffer[0]);
+    free(cNoiseBuffer[1]);
+    free(cNoiseBuffer[2]);
+    free(cNoiseBuffer[3]);
+    free(cNoiseBuffer[4]);
+    free(cBuffer);
+    free(dstBuffer);
+    free(mirrorBuffer);
+    return result;
+
+_output_error:
+    result = 1;
+    goto _cleanup;
+}
+
+
+/*_*******************************************************
+*  Command line
+*********************************************************/
+static int FUZ_usage(const char* programName)
+{
+    DISPLAY( "Usage :\n");
+    DISPLAY( "      %s [args]\n", programName);
+    DISPLAY( "\n");
+    DISPLAY( "Arguments :\n");
+    DISPLAY( " -i#    : Nb of tests (default:%u) \n", nbTestsDefault);
+    DISPLAY( " -s#    : Select seed (default:prompt user)\n");
+    DISPLAY( " -t#    : Select starting test number (default:0)\n");
+    DISPLAY( " -P#    : Select compressibility in %% (default:%u%%)\n", FUZ_compressibility_default);
+    DISPLAY( " -v     : verbose\n");
+    DISPLAY( " -p     : pause at the end\n");
+    DISPLAY( " -h     : display help and exit\n");
+    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 result can overflow if digit string > MAX_UINT */
+static unsigned readU32FromChar(const char** stringPtr)
+{
+    unsigned result = 0;
+    while ((**stringPtr >='0') && (**stringPtr <='9'))
+        result *= 10, result += **stringPtr - '0', (*stringPtr)++ ;
+    if ((**stringPtr=='K') || (**stringPtr=='M')) {
+        result <<= 10;
+        if (**stringPtr=='M') result <<= 10;
+        (*stringPtr)++ ;
+        if (**stringPtr=='i') (*stringPtr)++;
+        if (**stringPtr=='B') (*stringPtr)++;
+    }
+    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 unsigned 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;
+}
+
+int main(int argc, const char** argv)
+{
+    U32 seed = 0;
+    int seedset = 0;
+    int argNb;
+    int nbTests = nbTestsDefault;
+    int testNb = 0;
+    U32 proba = FUZ_compressibility_default;
+    int result = 0;
+    U32 mainPause = 0;
+    U32 maxDuration = 0;
+    int bigTests = 1;
+    U32 memTestsOnly = 0;
+    const char* const programName = argv[0];
+
+    /* Check command line */
+    for (argNb=1; argNb<argc; argNb++) {
+        const char* argument = argv[argNb];
+        if(!argument) continue;   /* Protection if argument empty */
+
+        /* Handle commands. Aggregated commands are allowed */
+        if (argument[0]=='-') {
+
+            if (longCommandWArg(&argument, "--memtest=")) { memTestsOnly = readU32FromChar(&argument); continue; }
+
+            if (!strcmp(argument, "--memtest")) { memTestsOnly=1; continue; }
+            if (!strcmp(argument, "--no-big-tests")) { bigTests=0; continue; }
+
+            argument++;
+            while (*argument!=0) {
+                switch(*argument)
+                {
+                case 'h':
+                    return FUZ_usage(programName);
+
+                case 'v':
+                    argument++;
+                    g_displayLevel = 4;
+                    break;
+
+                case 'q':
+                    argument++;
+                    g_displayLevel--;
+                    break;
+
+                case 'p': /* pause at the end */
+                    argument++;
+                    mainPause = 1;
+                    break;
+
+                case 'i':
+                    argument++; maxDuration = 0;
+                    nbTests = readU32FromChar(&argument);
+                    break;
+
+                case 'T':
+                    argument++;
+                    nbTests = 0;
+                    maxDuration = readU32FromChar(&argument);
+                    if (*argument=='s') argument++;   /* seconds */
+                    if (*argument=='m') maxDuration *= 60, argument++;   /* minutes */
+                    if (*argument=='n') argument++;
+                    break;
+
+                case 's':
+                    argument++;
+                    seedset = 1;
+                    seed = readU32FromChar(&argument);
+                    break;
+
+                case 't':
+                    argument++;
+                    testNb = readU32FromChar(&argument);
+                    break;
+
+                case 'P':   /* compressibility % */
+                    argument++;
+                    proba = readU32FromChar(&argument);
+                    if (proba>100) proba = 100;
+                    break;
+
+                default:
+                    return (FUZ_usage(programName), 1);
+    }   }   }   }   /* for (argNb=1; argNb<argc; argNb++) */
+
+    /* Get Seed */
+    DISPLAY("Starting zstd tester (%i-bits, %s)\n", (int)(sizeof(size_t)*8), ZSTD_VERSION_STRING);
+
+    if (!seedset) {
+        time_t const t = time(NULL);
+        U32 const h = XXH32(&t, sizeof(t), 1);
+        seed = h % 10000;
+    }
+
+    DISPLAY("Seed = %u\n", seed);
+    if (proba!=FUZ_compressibility_default) DISPLAY("Compressibility : %u%%\n", proba);
+
+    if (memTestsOnly) {
+        g_displayLevel = MAX(3, g_displayLevel);
+        return FUZ_mallocTests(seed, ((double)proba) / 100, memTestsOnly);
+    }
+
+    if (nbTests < testNb) nbTests = testNb;
+
+    if (testNb==0)
+        result = basicUnitTests(0, ((double)proba) / 100);  /* constant seed for predictability */
+    if (!result)
+        result = fuzzerTests(seed, nbTests, testNb, maxDuration, ((double)proba) / 100, bigTests);
+    if (mainPause) {
+        int unused;
+        DISPLAY("Press Enter \n");
+        unused = getchar();
+        (void)unused;
+    }
+    return result;
+}