summaryrefslogtreecommitdiffstats
path: root/src/zstd/contrib/seekable_format
diff options
context:
space:
mode:
Diffstat (limited to 'src/zstd/contrib/seekable_format')
-rw-r--r--src/zstd/contrib/seekable_format/examples/.gitignore4
-rw-r--r--src/zstd/contrib/seekable_format/examples/Makefile42
-rw-r--r--src/zstd/contrib/seekable_format/examples/parallel_compression.c215
-rw-r--r--src/zstd/contrib/seekable_format/examples/parallel_processing.c194
-rw-r--r--src/zstd/contrib/seekable_format/examples/seekable_compression.c132
-rw-r--r--src/zstd/contrib/seekable_format/examples/seekable_decompression.c138
-rw-r--r--src/zstd/contrib/seekable_format/zstd_seekable.h184
-rw-r--r--src/zstd/contrib/seekable_format/zstd_seekable_compression_format.md116
-rw-r--r--src/zstd/contrib/seekable_format/zstdseek_compress.c366
-rw-r--r--src/zstd/contrib/seekable_format/zstdseek_decompress.c462
10 files changed, 1853 insertions, 0 deletions
diff --git a/src/zstd/contrib/seekable_format/examples/.gitignore b/src/zstd/contrib/seekable_format/examples/.gitignore
new file mode 100644
index 00000000..df2f9ab0
--- /dev/null
+++ b/src/zstd/contrib/seekable_format/examples/.gitignore
@@ -0,0 +1,4 @@
+seekable_compression
+seekable_decompression
+parallel_processing
+parallel_compression
diff --git a/src/zstd/contrib/seekable_format/examples/Makefile b/src/zstd/contrib/seekable_format/examples/Makefile
new file mode 100644
index 00000000..1847aa7e
--- /dev/null
+++ b/src/zstd/contrib/seekable_format/examples/Makefile
@@ -0,0 +1,42 @@
+# ################################################################
+# Copyright (c) 2017-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 Makefile presumes libzstd is built, using `make` in / or /lib/
+
+LDFLAGS += ../../../lib/libzstd.a
+CPPFLAGS += -I../ -I../../../lib -I../../../lib/common
+
+CFLAGS ?= -O3
+CFLAGS += -g
+
+SEEKABLE_OBJS = ../zstdseek_compress.c ../zstdseek_decompress.c
+
+.PHONY: default all clean test
+
+default: all
+
+all: seekable_compression seekable_decompression parallel_processing
+
+seekable_compression : seekable_compression.c $(SEEKABLE_OBJS)
+ $(CC) $(CPPFLAGS) $(CFLAGS) $^ $(LDFLAGS) -o $@
+
+seekable_decompression : seekable_decompression.c $(SEEKABLE_OBJS)
+ $(CC) $(CPPFLAGS) $(CFLAGS) $^ $(LDFLAGS) -o $@
+
+parallel_processing : parallel_processing.c $(SEEKABLE_OBJS)
+ $(CC) $(CPPFLAGS) $(CFLAGS) $^ $(LDFLAGS) -o $@ -pthread
+
+parallel_compression : parallel_compression.c $(SEEKABLE_OBJS)
+ $(CC) $(CPPFLAGS) $(CFLAGS) $^ $(LDFLAGS) -o $@ -pthread
+
+clean:
+ @rm -f core *.o tmp* result* *.zst \
+ seekable_compression seekable_decompression \
+ parallel_processing parallel_compression
+ @echo Cleaning completed
diff --git a/src/zstd/contrib/seekable_format/examples/parallel_compression.c b/src/zstd/contrib/seekable_format/examples/parallel_compression.c
new file mode 100644
index 00000000..69644d2b
--- /dev/null
+++ b/src/zstd/contrib/seekable_format/examples/parallel_compression.c
@@ -0,0 +1,215 @@
+/*
+ * Copyright (c) 2017-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 <stdlib.h> // malloc, free, exit, atoi
+#include <stdio.h> // fprintf, perror, feof, fopen, etc.
+#include <string.h> // strlen, memset, strcat
+#define ZSTD_STATIC_LINKING_ONLY
+#include <zstd.h> // presumes zstd library is installed
+#include <zstd_errors.h>
+#if defined(WIN32) || defined(_WIN32)
+# include <windows.h>
+# define SLEEP(x) Sleep(x)
+#else
+# include <unistd.h>
+# define SLEEP(x) usleep(x * 1000)
+#endif
+
+#define XXH_NAMESPACE ZSTD_
+#include "xxhash.h"
+
+#include "pool.h" // use zstd thread pool for demo
+
+#include "zstd_seekable.h"
+
+static void* malloc_orDie(size_t size)
+{
+ void* const buff = malloc(size);
+ if (buff) return buff;
+ /* error */
+ perror("malloc:");
+ exit(1);
+}
+
+static FILE* fopen_orDie(const char *filename, const char *instruction)
+{
+ FILE* const inFile = fopen(filename, instruction);
+ if (inFile) return inFile;
+ /* error */
+ perror(filename);
+ exit(3);
+}
+
+static size_t fread_orDie(void* buffer, size_t sizeToRead, FILE* file)
+{
+ size_t const readSize = fread(buffer, 1, sizeToRead, file);
+ if (readSize == sizeToRead) return readSize; /* good */
+ if (feof(file)) return readSize; /* good, reached end of file */
+ /* error */
+ perror("fread");
+ exit(4);
+}
+
+static size_t fwrite_orDie(const void* buffer, size_t sizeToWrite, FILE* file)
+{
+ size_t const writtenSize = fwrite(buffer, 1, sizeToWrite, file);
+ if (writtenSize == sizeToWrite) return sizeToWrite; /* good */
+ /* error */
+ perror("fwrite");
+ exit(5);
+}
+
+static size_t fclose_orDie(FILE* file)
+{
+ if (!fclose(file)) return 0;
+ /* error */
+ perror("fclose");
+ exit(6);
+}
+
+static void fseek_orDie(FILE* file, long int offset, int origin)
+{
+ if (!fseek(file, offset, origin)) {
+ if (!fflush(file)) return;
+ }
+ /* error */
+ perror("fseek");
+ exit(7);
+}
+
+static long int ftell_orDie(FILE* file)
+{
+ long int off = ftell(file);
+ if (off != -1) return off;
+ /* error */
+ perror("ftell");
+ exit(8);
+}
+
+struct job {
+ const void* src;
+ size_t srcSize;
+ void* dst;
+ size_t dstSize;
+
+ unsigned checksum;
+
+ int compressionLevel;
+ int done;
+};
+
+static void compressFrame(void* opaque)
+{
+ struct job* job = opaque;
+
+ job->checksum = XXH64(job->src, job->srcSize, 0);
+
+ size_t ret = ZSTD_compress(job->dst, job->dstSize, job->src, job->srcSize, job->compressionLevel);
+ if (ZSTD_isError(ret)) {
+ fprintf(stderr, "ZSTD_compress() error : %s \n", ZSTD_getErrorName(ret));
+ exit(20);
+ }
+
+ job->dstSize = ret;
+ job->done = 1;
+}
+
+static void compressFile_orDie(const char* fname, const char* outName, int cLevel, unsigned frameSize, int nbThreads)
+{
+ POOL_ctx* pool = POOL_create(nbThreads, nbThreads);
+ if (pool == NULL) { fprintf(stderr, "POOL_create() error \n"); exit(9); }
+
+ FILE* const fin = fopen_orDie(fname, "rb");
+ FILE* const fout = fopen_orDie(outName, "wb");
+
+ if (ZSTD_compressBound(frameSize) > 0xFFFFFFFFU) { fprintf(stderr, "Frame size too large \n"); exit(10); }
+ unsigned dstSize = ZSTD_compressBound(frameSize);
+
+
+ fseek_orDie(fin, 0, SEEK_END);
+ long int length = ftell_orDie(fin);
+ fseek_orDie(fin, 0, SEEK_SET);
+
+ size_t numFrames = (length + frameSize - 1) / frameSize;
+
+ struct job* jobs = malloc_orDie(sizeof(struct job) * numFrames);
+
+ size_t i;
+ for(i = 0; i < numFrames; i++) {
+ void* in = malloc_orDie(frameSize);
+ void* out = malloc_orDie(dstSize);
+
+ size_t inSize = fread_orDie(in, frameSize, fin);
+
+ jobs[i].src = in;
+ jobs[i].srcSize = inSize;
+ jobs[i].dst = out;
+ jobs[i].dstSize = dstSize;
+ jobs[i].compressionLevel = cLevel;
+ jobs[i].done = 0;
+ POOL_add(pool, compressFrame, &jobs[i]);
+ }
+
+ ZSTD_frameLog* fl = ZSTD_seekable_createFrameLog(1);
+ if (fl == NULL) { fprintf(stderr, "ZSTD_seekable_createFrameLog() failed \n"); exit(11); }
+ for (i = 0; i < numFrames; i++) {
+ while (!jobs[i].done) SLEEP(5); /* wake up every 5 milliseconds to check */
+ fwrite_orDie(jobs[i].dst, jobs[i].dstSize, fout);
+ free((void*)jobs[i].src);
+ free(jobs[i].dst);
+
+ size_t ret = ZSTD_seekable_logFrame(fl, jobs[i].dstSize, jobs[i].srcSize, jobs[i].checksum);
+ if (ZSTD_isError(ret)) { fprintf(stderr, "ZSTD_seekable_logFrame() error : %s \n", ZSTD_getErrorName(ret)); }
+ }
+
+ { unsigned char seekTableBuff[1024];
+ ZSTD_outBuffer out = {seekTableBuff, 1024, 0};
+ while (ZSTD_seekable_writeSeekTable(fl, &out) != 0) {
+ fwrite_orDie(seekTableBuff, out.pos, fout);
+ out.pos = 0;
+ }
+ fwrite_orDie(seekTableBuff, out.pos, fout);
+ }
+
+ ZSTD_seekable_freeFrameLog(fl);
+ free(jobs);
+ fclose_orDie(fout);
+ fclose_orDie(fin);
+}
+
+static const char* createOutFilename_orDie(const char* filename)
+{
+ size_t const inL = strlen(filename);
+ size_t const outL = inL + 5;
+ void* outSpace = malloc_orDie(outL);
+ memset(outSpace, 0, outL);
+ strcat(outSpace, filename);
+ strcat(outSpace, ".zst");
+ return (const char*)outSpace;
+}
+
+int main(int argc, const char** argv) {
+ const char* const exeName = argv[0];
+ if (argc!=4) {
+ printf("wrong arguments\n");
+ printf("usage:\n");
+ printf("%s FILE FRAME_SIZE NB_THREADS\n", exeName);
+ return 1;
+ }
+
+ { const char* const inFileName = argv[1];
+ unsigned const frameSize = (unsigned)atoi(argv[2]);
+ int const nbThreads = atoi(argv[3]);
+
+ const char* const outFileName = createOutFilename_orDie(inFileName);
+ compressFile_orDie(inFileName, outFileName, 5, frameSize, nbThreads);
+ }
+
+ return 0;
+}
diff --git a/src/zstd/contrib/seekable_format/examples/parallel_processing.c b/src/zstd/contrib/seekable_format/examples/parallel_processing.c
new file mode 100644
index 00000000..da347763
--- /dev/null
+++ b/src/zstd/contrib/seekable_format/examples/parallel_processing.c
@@ -0,0 +1,194 @@
+/*
+ * Copyright (c) 2017-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).
+ */
+
+/*
+ * A simple demo that sums up all the bytes in the file in parallel using
+ * seekable decompression and the zstd thread pool
+ */
+
+#include <stdlib.h> // malloc, exit
+#include <stdio.h> // fprintf, perror, feof
+#include <string.h> // strerror
+#include <errno.h> // errno
+#define ZSTD_STATIC_LINKING_ONLY
+#include <zstd.h> // presumes zstd library is installed
+#include <zstd_errors.h>
+#if defined(WIN32) || defined(_WIN32)
+# include <windows.h>
+# define SLEEP(x) Sleep(x)
+#else
+# include <unistd.h>
+# define SLEEP(x) usleep(x * 1000)
+#endif
+
+#include "pool.h" // use zstd thread pool for demo
+
+#include "zstd_seekable.h"
+
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+
+static void* malloc_orDie(size_t size)
+{
+ void* const buff = malloc(size);
+ if (buff) return buff;
+ /* error */
+ perror("malloc");
+ exit(1);
+}
+
+static void* realloc_orDie(void* ptr, size_t size)
+{
+ ptr = realloc(ptr, size);
+ if (ptr) return ptr;
+ /* error */
+ perror("realloc");
+ exit(1);
+}
+
+static FILE* fopen_orDie(const char *filename, const char *instruction)
+{
+ FILE* const inFile = fopen(filename, instruction);
+ if (inFile) return inFile;
+ /* error */
+ perror(filename);
+ exit(3);
+}
+
+static size_t fread_orDie(void* buffer, size_t sizeToRead, FILE* file)
+{
+ size_t const readSize = fread(buffer, 1, sizeToRead, file);
+ if (readSize == sizeToRead) return readSize; /* good */
+ if (feof(file)) return readSize; /* good, reached end of file */
+ /* error */
+ perror("fread");
+ exit(4);
+}
+
+static size_t fwrite_orDie(const void* buffer, size_t sizeToWrite, FILE* file)
+{
+ size_t const writtenSize = fwrite(buffer, 1, sizeToWrite, file);
+ if (writtenSize == sizeToWrite) return sizeToWrite; /* good */
+ /* error */
+ perror("fwrite");
+ exit(5);
+}
+
+static size_t fclose_orDie(FILE* file)
+{
+ if (!fclose(file)) return 0;
+ /* error */
+ perror("fclose");
+ exit(6);
+}
+
+static void fseek_orDie(FILE* file, long int offset, int origin) {
+ if (!fseek(file, offset, origin)) {
+ if (!fflush(file)) return;
+ }
+ /* error */
+ perror("fseek");
+ exit(7);
+}
+
+struct sum_job {
+ const char* fname;
+ unsigned long long sum;
+ unsigned frameNb;
+ int done;
+};
+
+static void sumFrame(void* opaque)
+{
+ struct sum_job* job = (struct sum_job*)opaque;
+ job->done = 0;
+
+ FILE* const fin = fopen_orDie(job->fname, "rb");
+
+ ZSTD_seekable* const seekable = ZSTD_seekable_create();
+ if (seekable==NULL) { fprintf(stderr, "ZSTD_seekable_create() error \n"); exit(10); }
+
+ size_t const initResult = ZSTD_seekable_initFile(seekable, fin);
+ if (ZSTD_isError(initResult)) { fprintf(stderr, "ZSTD_seekable_init() error : %s \n", ZSTD_getErrorName(initResult)); exit(11); }
+
+ size_t const frameSize = ZSTD_seekable_getFrameDecompressedSize(seekable, job->frameNb);
+ unsigned char* data = malloc_orDie(frameSize);
+
+ size_t result = ZSTD_seekable_decompressFrame(seekable, data, frameSize, job->frameNb);
+ if (ZSTD_isError(result)) { fprintf(stderr, "ZSTD_seekable_decompressFrame() error : %s \n", ZSTD_getErrorName(result)); exit(12); }
+
+ unsigned long long sum = 0;
+ size_t i;
+ for (i = 0; i < frameSize; i++) {
+ sum += data[i];
+ }
+ job->sum = sum;
+ job->done = 1;
+
+ fclose(fin);
+ ZSTD_seekable_free(seekable);
+ free(data);
+}
+
+static void sumFile_orDie(const char* fname, int nbThreads)
+{
+ POOL_ctx* pool = POOL_create(nbThreads, nbThreads);
+ if (pool == NULL) { fprintf(stderr, "POOL_create() error \n"); exit(9); }
+
+ FILE* const fin = fopen_orDie(fname, "rb");
+
+ ZSTD_seekable* const seekable = ZSTD_seekable_create();
+ if (seekable==NULL) { fprintf(stderr, "ZSTD_seekable_create() error \n"); exit(10); }
+
+ size_t const initResult = ZSTD_seekable_initFile(seekable, fin);
+ if (ZSTD_isError(initResult)) { fprintf(stderr, "ZSTD_seekable_init() error : %s \n", ZSTD_getErrorName(initResult)); exit(11); }
+
+ size_t const numFrames = ZSTD_seekable_getNumFrames(seekable);
+ struct sum_job* jobs = (struct sum_job*)malloc(numFrames * sizeof(struct sum_job));
+
+ size_t i;
+ for (i = 0; i < numFrames; i++) {
+ jobs[i] = (struct sum_job){ fname, 0, i, 0 };
+ POOL_add(pool, sumFrame, &jobs[i]);
+ }
+
+ unsigned long long total = 0;
+
+ for (i = 0; i < numFrames; i++) {
+ while (!jobs[i].done) SLEEP(5); /* wake up every 5 milliseconds to check */
+ total += jobs[i].sum;
+ }
+
+ printf("Sum: %llu\n", total);
+
+ POOL_free(pool);
+ ZSTD_seekable_free(seekable);
+ fclose(fin);
+ free(jobs);
+}
+
+
+int main(int argc, const char** argv)
+{
+ const char* const exeName = argv[0];
+
+ if (argc!=3) {
+ fprintf(stderr, "wrong arguments\n");
+ fprintf(stderr, "usage:\n");
+ fprintf(stderr, "%s FILE NB_THREADS\n", exeName);
+ return 1;
+ }
+
+ {
+ const char* const inFilename = argv[1];
+ int const nbThreads = atoi(argv[2]);
+ sumFile_orDie(inFilename, nbThreads);
+ }
+
+ return 0;
+}
diff --git a/src/zstd/contrib/seekable_format/examples/seekable_compression.c b/src/zstd/contrib/seekable_format/examples/seekable_compression.c
new file mode 100644
index 00000000..9485bf26
--- /dev/null
+++ b/src/zstd/contrib/seekable_format/examples/seekable_compression.c
@@ -0,0 +1,132 @@
+/*
+ * Copyright (c) 2017-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 <stdlib.h> // malloc, free, exit, atoi
+#include <stdio.h> // fprintf, perror, feof, fopen, etc.
+#include <string.h> // strlen, memset, strcat
+#define ZSTD_STATIC_LINKING_ONLY
+#include <zstd.h> // presumes zstd library is installed
+
+#include "zstd_seekable.h"
+
+static void* malloc_orDie(size_t size)
+{
+ void* const buff = malloc(size);
+ if (buff) return buff;
+ /* error */
+ perror("malloc:");
+ exit(1);
+}
+
+static FILE* fopen_orDie(const char *filename, const char *instruction)
+{
+ FILE* const inFile = fopen(filename, instruction);
+ if (inFile) return inFile;
+ /* error */
+ perror(filename);
+ exit(3);
+}
+
+static size_t fread_orDie(void* buffer, size_t sizeToRead, FILE* file)
+{
+ size_t const readSize = fread(buffer, 1, sizeToRead, file);
+ if (readSize == sizeToRead) return readSize; /* good */
+ if (feof(file)) return readSize; /* good, reached end of file */
+ /* error */
+ perror("fread");
+ exit(4);
+}
+
+static size_t fwrite_orDie(const void* buffer, size_t sizeToWrite, FILE* file)
+{
+ size_t const writtenSize = fwrite(buffer, 1, sizeToWrite, file);
+ if (writtenSize == sizeToWrite) return sizeToWrite; /* good */
+ /* error */
+ perror("fwrite");
+ exit(5);
+}
+
+static size_t fclose_orDie(FILE* file)
+{
+ if (!fclose(file)) return 0;
+ /* error */
+ perror("fclose");
+ exit(6);
+}
+
+static void compressFile_orDie(const char* fname, const char* outName, int cLevel, unsigned frameSize)
+{
+ FILE* const fin = fopen_orDie(fname, "rb");
+ FILE* const fout = fopen_orDie(outName, "wb");
+ size_t const buffInSize = ZSTD_CStreamInSize(); /* can always read one full block */
+ void* const buffIn = malloc_orDie(buffInSize);
+ size_t const buffOutSize = ZSTD_CStreamOutSize(); /* can always flush a full block */
+ void* const buffOut = malloc_orDie(buffOutSize);
+
+ ZSTD_seekable_CStream* const cstream = ZSTD_seekable_createCStream();
+ if (cstream==NULL) { fprintf(stderr, "ZSTD_seekable_createCStream() error \n"); exit(10); }
+ size_t const initResult = ZSTD_seekable_initCStream(cstream, cLevel, 1, frameSize);
+ if (ZSTD_isError(initResult)) { fprintf(stderr, "ZSTD_seekable_initCStream() error : %s \n", ZSTD_getErrorName(initResult)); exit(11); }
+
+ size_t read, toRead = buffInSize;
+ while( (read = fread_orDie(buffIn, toRead, fin)) ) {
+ ZSTD_inBuffer input = { buffIn, read, 0 };
+ while (input.pos < input.size) {
+ ZSTD_outBuffer output = { buffOut, buffOutSize, 0 };
+ toRead = ZSTD_seekable_compressStream(cstream, &output , &input); /* toRead is guaranteed to be <= ZSTD_CStreamInSize() */
+ if (ZSTD_isError(toRead)) { fprintf(stderr, "ZSTD_seekable_compressStream() error : %s \n", ZSTD_getErrorName(toRead)); exit(12); }
+ if (toRead > buffInSize) toRead = buffInSize; /* Safely handle case when `buffInSize` is manually changed to a value < ZSTD_CStreamInSize()*/
+ fwrite_orDie(buffOut, output.pos, fout);
+ }
+ }
+
+ while (1) {
+ ZSTD_outBuffer output = { buffOut, buffOutSize, 0 };
+ size_t const remainingToFlush = ZSTD_seekable_endStream(cstream, &output); /* close stream */
+ if (ZSTD_isError(remainingToFlush)) { fprintf(stderr, "ZSTD_seekable_endStream() error : %s \n", ZSTD_getErrorName(remainingToFlush)); exit(13); }
+ fwrite_orDie(buffOut, output.pos, fout);
+ if (!remainingToFlush) break;
+ }
+
+ ZSTD_seekable_freeCStream(cstream);
+ fclose_orDie(fout);
+ fclose_orDie(fin);
+ free(buffIn);
+ free(buffOut);
+}
+
+static const char* createOutFilename_orDie(const char* filename)
+{
+ size_t const inL = strlen(filename);
+ size_t const outL = inL + 5;
+ void* outSpace = malloc_orDie(outL);
+ memset(outSpace, 0, outL);
+ strcat(outSpace, filename);
+ strcat(outSpace, ".zst");
+ return (const char*)outSpace;
+}
+
+int main(int argc, const char** argv) {
+ const char* const exeName = argv[0];
+ if (argc!=3) {
+ printf("wrong arguments\n");
+ printf("usage:\n");
+ printf("%s FILE FRAME_SIZE\n", exeName);
+ return 1;
+ }
+
+ { const char* const inFileName = argv[1];
+ unsigned const frameSize = (unsigned)atoi(argv[2]);
+
+ const char* const outFileName = createOutFilename_orDie(inFileName);
+ compressFile_orDie(inFileName, outFileName, 5, frameSize);
+ }
+
+ return 0;
+}
diff --git a/src/zstd/contrib/seekable_format/examples/seekable_decompression.c b/src/zstd/contrib/seekable_format/examples/seekable_decompression.c
new file mode 100644
index 00000000..9cd23292
--- /dev/null
+++ b/src/zstd/contrib/seekable_format/examples/seekable_decompression.c
@@ -0,0 +1,138 @@
+/*
+ * Copyright (c) 2017-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 <stdlib.h> // malloc, exit
+#include <stdio.h> // fprintf, perror, feof
+#include <string.h> // strerror
+#include <errno.h> // errno
+#define ZSTD_STATIC_LINKING_ONLY
+#include <zstd.h> // presumes zstd library is installed
+#include <zstd_errors.h>
+
+#include "zstd_seekable.h"
+
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+
+static void* malloc_orDie(size_t size)
+{
+ void* const buff = malloc(size);
+ if (buff) return buff;
+ /* error */
+ perror("malloc");
+ exit(1);
+}
+
+static void* realloc_orDie(void* ptr, size_t size)
+{
+ ptr = realloc(ptr, size);
+ if (ptr) return ptr;
+ /* error */
+ perror("realloc");
+ exit(1);
+}
+
+static FILE* fopen_orDie(const char *filename, const char *instruction)
+{
+ FILE* const inFile = fopen(filename, instruction);
+ if (inFile) return inFile;
+ /* error */
+ perror(filename);
+ exit(3);
+}
+
+static size_t fread_orDie(void* buffer, size_t sizeToRead, FILE* file)
+{
+ size_t const readSize = fread(buffer, 1, sizeToRead, file);
+ if (readSize == sizeToRead) return readSize; /* good */
+ if (feof(file)) return readSize; /* good, reached end of file */
+ /* error */
+ perror("fread");
+ exit(4);
+}
+
+static size_t fwrite_orDie(const void* buffer, size_t sizeToWrite, FILE* file)
+{
+ size_t const writtenSize = fwrite(buffer, 1, sizeToWrite, file);
+ if (writtenSize == sizeToWrite) return sizeToWrite; /* good */
+ /* error */
+ perror("fwrite");
+ exit(5);
+}
+
+static size_t fclose_orDie(FILE* file)
+{
+ if (!fclose(file)) return 0;
+ /* error */
+ perror("fclose");
+ exit(6);
+}
+
+static void fseek_orDie(FILE* file, long int offset, int origin) {
+ if (!fseek(file, offset, origin)) {
+ if (!fflush(file)) return;
+ }
+ /* error */
+ perror("fseek");
+ exit(7);
+}
+
+
+static void decompressFile_orDie(const char* fname, unsigned startOffset, unsigned endOffset)
+{
+ FILE* const fin = fopen_orDie(fname, "rb");
+ FILE* const fout = stdout;
+ size_t const buffOutSize = ZSTD_DStreamOutSize(); /* Guarantee to successfully flush at least one complete compressed block in all circumstances. */
+ void* const buffOut = malloc_orDie(buffOutSize);
+
+ ZSTD_seekable* const seekable = ZSTD_seekable_create();
+ if (seekable==NULL) { fprintf(stderr, "ZSTD_seekable_create() error \n"); exit(10); }
+
+ size_t const initResult = ZSTD_seekable_initFile(seekable, fin);
+ if (ZSTD_isError(initResult)) { fprintf(stderr, "ZSTD_seekable_init() error : %s \n", ZSTD_getErrorName(initResult)); exit(11); }
+
+ while (startOffset < endOffset) {
+ size_t const result = ZSTD_seekable_decompress(seekable, buffOut, MIN(endOffset - startOffset, buffOutSize), startOffset);
+
+ if (ZSTD_isError(result)) {
+ fprintf(stderr, "ZSTD_seekable_decompress() error : %s \n",
+ ZSTD_getErrorName(result));
+ exit(12);
+ }
+ fwrite_orDie(buffOut, result, fout);
+ startOffset += result;
+ }
+
+ ZSTD_seekable_free(seekable);
+ fclose_orDie(fin);
+ fclose_orDie(fout);
+ free(buffOut);
+}
+
+
+int main(int argc, const char** argv)
+{
+ const char* const exeName = argv[0];
+
+ if (argc!=4) {
+ fprintf(stderr, "wrong arguments\n");
+ fprintf(stderr, "usage:\n");
+ fprintf(stderr, "%s FILE START END\n", exeName);
+ return 1;
+ }
+
+ {
+ const char* const inFilename = argv[1];
+ unsigned const startOffset = (unsigned) atoi(argv[2]);
+ unsigned const endOffset = (unsigned) atoi(argv[3]);
+ decompressFile_orDie(inFilename, startOffset, endOffset);
+ }
+
+ return 0;
+}
diff --git a/src/zstd/contrib/seekable_format/zstd_seekable.h b/src/zstd/contrib/seekable_format/zstd_seekable.h
new file mode 100644
index 00000000..438ac201
--- /dev/null
+++ b/src/zstd/contrib/seekable_format/zstd_seekable.h
@@ -0,0 +1,184 @@
+#ifndef SEEKABLE_H
+#define SEEKABLE_H
+
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
+#include <stdio.h>
+
+static const unsigned ZSTD_seekTableFooterSize = 9;
+
+#define ZSTD_SEEKABLE_MAGICNUMBER 0x8F92EAB1
+
+#define ZSTD_SEEKABLE_MAXFRAMES 0x8000000U
+
+/* Limit the maximum size to avoid any potential issues storing the compressed size */
+#define ZSTD_SEEKABLE_MAX_FRAME_DECOMPRESSED_SIZE 0x80000000U
+
+/*-****************************************************************************
+* Seekable Format
+*
+* The seekable format splits the compressed data into a series of "frames",
+* each compressed individually so that decompression of a section in the
+* middle of an archive only requires zstd to decompress at most a frame's
+* worth of extra data, instead of the entire archive.
+******************************************************************************/
+
+typedef struct ZSTD_seekable_CStream_s ZSTD_seekable_CStream;
+typedef struct ZSTD_seekable_s ZSTD_seekable;
+
+/*-****************************************************************************
+* Seekable compression - HowTo
+* A ZSTD_seekable_CStream object is required to tracking streaming operation.
+* Use ZSTD_seekable_createCStream() and ZSTD_seekable_freeCStream() to create/
+* release resources.
+*
+* Streaming objects are reusable to avoid allocation and deallocation,
+* to start a new compression operation call ZSTD_seekable_initCStream() on the
+* compressor.
+*
+* Data streamed to the seekable compressor will automatically be split into
+* frames of size `maxFrameSize` (provided in ZSTD_seekable_initCStream()),
+* or if none is provided, will be cut off whenever ZSTD_seekable_endFrame() is
+* called or when the default maximum frame size (2GB) is reached.
+*
+* Use ZSTD_seekable_initCStream() to initialize a ZSTD_seekable_CStream object
+* for a new compression operation.
+* `maxFrameSize` indicates the size at which to automatically start a new
+* seekable frame. `maxFrameSize == 0` implies the default maximum size.
+* `checksumFlag` indicates whether or not the seek table should include frame
+* checksums on the uncompressed data for verification.
+* @return : a size hint for input to provide for compression, or an error code
+* checkable with ZSTD_isError()
+*
+* Use ZSTD_seekable_compressStream() repetitively to consume input stream.
+* The function will automatically update both `pos` fields.
+* Note that it may not consume the entire input, in which case `pos < size`,
+* and it's up to the caller to present again remaining data.
+* @return : a size hint, preferred nb of bytes to use as input for next
+* function call or an error code, which can be tested using
+* ZSTD_isError().
+* Note 1 : it's just a hint, to help latency a little, any other
+* value will work fine.
+*
+* At any time, call ZSTD_seekable_endFrame() to end the current frame and
+* start a new one.
+*
+* ZSTD_seekable_endStream() will end the current frame, and then write the seek
+* table so that decompressors can efficiently find compressed frames.
+* ZSTD_seekable_endStream() may return a number > 0 if it was unable to flush
+* all the necessary data to `output`. In this case, it should be called again
+* until all remaining data is flushed out and 0 is returned.
+******************************************************************************/
+
+/*===== Seekable compressor management =====*/
+ZSTDLIB_API ZSTD_seekable_CStream* ZSTD_seekable_createCStream(void);
+ZSTDLIB_API size_t ZSTD_seekable_freeCStream(ZSTD_seekable_CStream* zcs);
+
+/*===== Seekable compression functions =====*/
+ZSTDLIB_API size_t ZSTD_seekable_initCStream(ZSTD_seekable_CStream* zcs, int compressionLevel, int checksumFlag, unsigned maxFrameSize);
+ZSTDLIB_API size_t ZSTD_seekable_compressStream(ZSTD_seekable_CStream* zcs, ZSTD_outBuffer* output, ZSTD_inBuffer* input);
+ZSTDLIB_API size_t ZSTD_seekable_endFrame(ZSTD_seekable_CStream* zcs, ZSTD_outBuffer* output);
+ZSTDLIB_API size_t ZSTD_seekable_endStream(ZSTD_seekable_CStream* zcs, ZSTD_outBuffer* output);
+
+/*= Raw seek table API
+ * These functions allow for the seek table to be constructed directly.
+ * This table can then be appended to a file of concatenated frames.
+ * This allows the frames to be compressed independently, even in parallel,
+ * and compiled together afterward into a seekable archive.
+ *
+ * Use ZSTD_seekable_createFrameLog() to allocate and initialize a tracking
+ * structure.
+ *
+ * Call ZSTD_seekable_logFrame() once for each frame in the archive.
+ * checksum is optional, and will not be used if checksumFlag was 0 when the
+ * frame log was created. If present, it should be the least significant 32
+ * bits of the XXH64 hash of the uncompressed data.
+ *
+ * Call ZSTD_seekable_writeSeekTable to serialize the data into a seek table.
+ * If the entire table was written, the return value will be 0. Otherwise,
+ * it will be equal to the number of bytes left to write. */
+typedef struct ZSTD_frameLog_s ZSTD_frameLog;
+ZSTDLIB_API ZSTD_frameLog* ZSTD_seekable_createFrameLog(int checksumFlag);
+ZSTDLIB_API size_t ZSTD_seekable_freeFrameLog(ZSTD_frameLog* fl);
+ZSTDLIB_API size_t ZSTD_seekable_logFrame(ZSTD_frameLog* fl, unsigned compressedSize, unsigned decompressedSize, unsigned checksum);
+ZSTDLIB_API size_t ZSTD_seekable_writeSeekTable(ZSTD_frameLog* fl, ZSTD_outBuffer* output);
+
+/*-****************************************************************************
+* Seekable decompression - HowTo
+* A ZSTD_seekable object is required to tracking the seekTable.
+*
+* Call ZSTD_seekable_init* to initialize a ZSTD_seekable object with the
+* the seek table provided in the input.
+* There are three modes for ZSTD_seekable_init:
+* - ZSTD_seekable_initBuff() : An in-memory API. The data contained in
+* `src` should be the entire seekable file, including the seek table.
+* `src` should be kept alive and unmodified until the ZSTD_seekable object
+* is freed or reset.
+* - ZSTD_seekable_initFile() : A simplified file API using stdio. fread and
+* fseek will be used to access the required data for building the seek
+* table and doing decompression operations. `src` should not be closed
+* or modified until the ZSTD_seekable object is freed or reset.
+* - ZSTD_seekable_initAdvanced() : A general API allowing the client to
+* provide its own read and seek callbacks.
+* + ZSTD_seekable_read() : read exactly `n` bytes into `buffer`.
+* Premature EOF should be treated as an error.
+* + ZSTD_seekable_seek() : seek the read head to `offset` from `origin`,
+* where origin is either SEEK_SET (beginning of
+* file), or SEEK_END (end of file).
+* Both functions should return a non-negative value in case of success, and a
+* negative value in case of failure. If implementing using this API and
+* stdio, be careful with files larger than 4GB and fseek. All of these
+* functions return an error code checkable with ZSTD_isError().
+*
+* Call ZSTD_seekable_decompress to decompress `dstSize` bytes at decompressed
+* offset `offset`. ZSTD_seekable_decompress may have to decompress the entire
+* prefix of the frame before the desired data if it has not already processed
+* this section. If ZSTD_seekable_decompress is called multiple times for a
+* consecutive range of data, it will efficiently retain the decompressor object
+* and avoid redecompressing frame prefixes. The return value is the number of
+* bytes decompressed, or an error code checkable with ZSTD_isError().
+*
+* The seek table access functions can be used to obtain the data contained
+* in the seek table. If frameIndex is larger than the value returned by
+* ZSTD_seekable_getNumFrames(), they will return error codes checkable with
+* ZSTD_isError(). Note that since the offset access functions return
+* unsigned long long instead of size_t, in this case they will instead return
+* the value ZSTD_SEEKABLE_FRAMEINDEX_TOOLARGE.
+******************************************************************************/
+
+/*===== Seekable decompressor management =====*/
+ZSTDLIB_API ZSTD_seekable* ZSTD_seekable_create(void);
+ZSTDLIB_API size_t ZSTD_seekable_free(ZSTD_seekable* zs);
+
+/*===== Seekable decompression functions =====*/
+ZSTDLIB_API size_t ZSTD_seekable_initBuff(ZSTD_seekable* zs, const void* src, size_t srcSize);
+ZSTDLIB_API size_t ZSTD_seekable_initFile(ZSTD_seekable* zs, FILE* src);
+ZSTDLIB_API size_t ZSTD_seekable_decompress(ZSTD_seekable* zs, void* dst, size_t dstSize, unsigned long long offset);
+ZSTDLIB_API size_t ZSTD_seekable_decompressFrame(ZSTD_seekable* zs, void* dst, size_t dstSize, unsigned frameIndex);
+
+#define ZSTD_SEEKABLE_FRAMEINDEX_TOOLARGE (0ULL-2)
+/*===== Seek Table access functions =====*/
+ZSTDLIB_API unsigned ZSTD_seekable_getNumFrames(ZSTD_seekable* const zs);
+ZSTDLIB_API unsigned long long ZSTD_seekable_getFrameCompressedOffset(ZSTD_seekable* const zs, unsigned frameIndex);
+ZSTDLIB_API unsigned long long ZSTD_seekable_getFrameDecompressedOffset(ZSTD_seekable* const zs, unsigned frameIndex);
+ZSTDLIB_API size_t ZSTD_seekable_getFrameCompressedSize(ZSTD_seekable* const zs, unsigned frameIndex);
+ZSTDLIB_API size_t ZSTD_seekable_getFrameDecompressedSize(ZSTD_seekable* const zs, unsigned frameIndex);
+ZSTDLIB_API unsigned ZSTD_seekable_offsetToFrameIndex(ZSTD_seekable* const zs, unsigned long long offset);
+
+/*===== Seekable advanced I/O API =====*/
+typedef int(ZSTD_seekable_read)(void* opaque, void* buffer, size_t n);
+typedef int(ZSTD_seekable_seek)(void* opaque, long long offset, int origin);
+typedef struct {
+ void* opaque;
+ ZSTD_seekable_read* read;
+ ZSTD_seekable_seek* seek;
+} ZSTD_seekable_customFile;
+ZSTDLIB_API size_t ZSTD_seekable_initAdvanced(ZSTD_seekable* zs, ZSTD_seekable_customFile src);
+
+#if defined (__cplusplus)
+}
+#endif
+
+#endif
diff --git a/src/zstd/contrib/seekable_format/zstd_seekable_compression_format.md b/src/zstd/contrib/seekable_format/zstd_seekable_compression_format.md
new file mode 100644
index 00000000..bf3080f7
--- /dev/null
+++ b/src/zstd/contrib/seekable_format/zstd_seekable_compression_format.md
@@ -0,0 +1,116 @@
+# Zstandard Seekable Format
+
+### Notices
+
+Copyright (c) 2017-present Facebook, Inc.
+
+Permission is granted to copy and distribute this document
+for any purpose and without charge,
+including translations into other languages
+and incorporation into compilations,
+provided that the copyright notice and this notice are preserved,
+and that any substantive changes or deletions from the original
+are clearly marked.
+Distribution of this document is unlimited.
+
+### Version
+0.1.0 (11/04/17)
+
+## Introduction
+This document defines a format for compressed data to be stored so that subranges of the data can be efficiently decompressed without requiring the entire document to be decompressed.
+This is done by splitting up the input data into frames,
+each of which are compressed independently,
+and so can be decompressed independently.
+Decompression then takes advantage of a provided 'seek table', which allows the decompressor to immediately jump to the desired data. This is done in a way that is compatible with the original Zstandard format by placing the seek table in a Zstandard skippable frame.
+
+### Overall conventions
+In this document:
+- square brackets i.e. `[` and `]` are used to indicate optional fields or parameters.
+- the naming convention for identifiers is `Mixed_Case_With_Underscores`
+- All numeric fields are little-endian unless specified otherwise
+
+## Format
+
+The format consists of a number of frames (Zstandard compressed frames and skippable frames), followed by a final skippable frame at the end containing the seek table.
+
+### Seek Table Format
+The structure of the seek table frame is as follows:
+
+|`Skippable_Magic_Number`|`Frame_Size`|`[Seek_Table_Entries]`|`Seek_Table_Footer`|
+|------------------------|------------|----------------------|-------------------|
+| 4 bytes | 4 bytes | 8-12 bytes each | 9 bytes |
+
+__`Skippable_Magic_Number`__
+
+Value : 0x184D2A5E.
+This is for compatibility with [Zstandard skippable frames].
+Since it is legal for other Zstandard skippable frames to use the same
+magic number, it is not recommended for a decoder to recognize frames
+solely on this.
+
+__`Frame_Size`__
+
+The total size of the skippable frame, not including the `Skippable_Magic_Number` or `Frame_Size`.
+This is for compatibility with [Zstandard skippable frames].
+
+[Zstandard skippable frames]: https://github.com/facebook/zstd/blob/master/doc/zstd_compression_format.md#skippable-frames
+
+#### `Seek_Table_Footer`
+The seek table footer format is as follows:
+
+|`Number_Of_Frames`|`Seek_Table_Descriptor`|`Seekable_Magic_Number`|
+|------------------|-----------------------|-----------------------|
+| 4 bytes | 1 byte | 4 bytes |
+
+__`Seekable_Magic_Number`__
+
+Value : 0x8F92EAB1.
+This value must be the last bytes present in the compressed file so that decoders
+can efficiently find it and determine if there is an actual seek table present.
+
+__`Number_Of_Frames`__
+
+The number of stored frames in the data.
+
+__`Seek_Table_Descriptor`__
+
+A bitfield describing the format of the seek table.
+
+| Bit number | Field name |
+| ---------- | ---------- |
+| 7 | `Checksum_Flag` |
+| 6-2 | `Reserved_Bits` |
+| 1-0 | `Unused_Bits` |
+
+While only `Checksum_Flag` currently exists, there are 7 other bits in this field that can be used for future changes to the format,
+for example the addition of inline dictionaries.
+
+__`Checksum_Flag`__
+
+If the checksum flag is set, each of the seek table entries contains a 4 byte checksum of the uncompressed data contained in its frame.
+
+`Reserved_Bits` are not currently used but may be used in the future for breaking changes, so a compliant decoder should ensure they are set to 0. `Unused_Bits` may be used in the future for non-breaking changes, so a compliant decoder should not interpret these bits.
+
+#### __`Seek_Table_Entries`__
+
+`Seek_Table_Entries` consists of `Number_Of_Frames` (one for each frame in the data, not including the seek table frame) entries of the following form, in sequence:
+
+|`Compressed_Size`|`Decompressed_Size`|`[Checksum]`|
+|-----------------|-------------------|------------|
+| 4 bytes | 4 bytes | 4 bytes |
+
+__`Compressed_Size`__
+
+The compressed size of the frame.
+The cumulative sum of the `Compressed_Size` fields of frames `0` to `i` gives the offset in the compressed file of frame `i+1`.
+
+__`Decompressed_Size`__
+
+The size of the decompressed data contained in the frame. For skippable or otherwise empty frames, this value is 0.
+
+__`Checksum`__
+
+Only present if `Checksum_Flag` is set in the `Seek_Table_Descriptor`. Value : the least significant 32 bits of the XXH64 digest of the uncompressed data, stored in little-endian format.
+
+## Version Changes
+- 0.1.0: initial version
diff --git a/src/zstd/contrib/seekable_format/zstdseek_compress.c b/src/zstd/contrib/seekable_format/zstdseek_compress.c
new file mode 100644
index 00000000..df207498
--- /dev/null
+++ b/src/zstd/contrib/seekable_format/zstdseek_compress.c
@@ -0,0 +1,366 @@
+/*
+ * Copyright (c) 2017-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 <stdlib.h> /* malloc, free */
+
+#define XXH_STATIC_LINKING_ONLY
+#define XXH_NAMESPACE ZSTD_
+#include "xxhash.h"
+
+#define ZSTD_STATIC_LINKING_ONLY
+#include "zstd.h"
+#include "zstd_errors.h"
+#include "mem.h"
+#include "zstd_seekable.h"
+
+#define CHECK_Z(f) { size_t const ret = (f); if (ret != 0) return ret; }
+
+#undef ERROR
+#define ERROR(name) ((size_t)-ZSTD_error_##name)
+
+#undef MIN
+#undef MAX
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+
+typedef struct {
+ U32 cSize;
+ U32 dSize;
+ U32 checksum;
+} framelogEntry_t;
+
+struct ZSTD_frameLog_s {
+ framelogEntry_t* entries;
+ U32 size;
+ U32 capacity;
+
+ int checksumFlag;
+
+ /* for use when streaming out the seek table */
+ U32 seekTablePos;
+ U32 seekTableIndex;
+} framelog_t;
+
+struct ZSTD_seekable_CStream_s {
+ ZSTD_CStream* cstream;
+ ZSTD_frameLog framelog;
+
+ U32 frameCSize;
+ U32 frameDSize;
+
+ XXH64_state_t xxhState;
+
+ U32 maxFrameSize;
+
+ int writingSeekTable;
+};
+
+size_t ZSTD_seekable_frameLog_allocVec(ZSTD_frameLog* fl)
+{
+ /* allocate some initial space */
+ size_t const FRAMELOG_STARTING_CAPACITY = 16;
+ fl->entries = (framelogEntry_t*)malloc(
+ sizeof(framelogEntry_t) * FRAMELOG_STARTING_CAPACITY);
+ if (fl->entries == NULL) return ERROR(memory_allocation);
+ fl->capacity = FRAMELOG_STARTING_CAPACITY;
+
+ return 0;
+}
+
+size_t ZSTD_seekable_frameLog_freeVec(ZSTD_frameLog* fl)
+{
+ if (fl != NULL) free(fl->entries);
+ return 0;
+}
+
+ZSTD_frameLog* ZSTD_seekable_createFrameLog(int checksumFlag)
+{
+ ZSTD_frameLog* fl = malloc(sizeof(ZSTD_frameLog));
+ if (fl == NULL) return NULL;
+
+ if (ZSTD_isError(ZSTD_seekable_frameLog_allocVec(fl))) {
+ free(fl);
+ return NULL;
+ }
+
+ fl->checksumFlag = checksumFlag;
+ fl->seekTablePos = 0;
+ fl->seekTableIndex = 0;
+ fl->size = 0;
+
+ return fl;
+}
+
+size_t ZSTD_seekable_freeFrameLog(ZSTD_frameLog* fl)
+{
+ ZSTD_seekable_frameLog_freeVec(fl);
+ free(fl);
+ return 0;
+}
+
+ZSTD_seekable_CStream* ZSTD_seekable_createCStream()
+{
+ ZSTD_seekable_CStream* zcs = malloc(sizeof(ZSTD_seekable_CStream));
+
+ if (zcs == NULL) return NULL;
+
+ memset(zcs, 0, sizeof(*zcs));
+
+ zcs->cstream = ZSTD_createCStream();
+ if (zcs->cstream == NULL) goto failed1;
+
+ if (ZSTD_isError(ZSTD_seekable_frameLog_allocVec(&zcs->framelog))) goto failed2;
+
+ return zcs;
+
+failed2:
+ ZSTD_freeCStream(zcs->cstream);
+failed1:
+ free(zcs);
+ return NULL;
+}
+
+size_t ZSTD_seekable_freeCStream(ZSTD_seekable_CStream* zcs)
+{
+ if (zcs == NULL) return 0; /* support free on null */
+ ZSTD_freeCStream(zcs->cstream);
+ ZSTD_seekable_frameLog_freeVec(&zcs->framelog);
+ free(zcs);
+
+ return 0;
+}
+
+size_t ZSTD_seekable_initCStream(ZSTD_seekable_CStream* zcs,
+ int compressionLevel,
+ int checksumFlag,
+ U32 maxFrameSize)
+{
+ zcs->framelog.size = 0;
+ zcs->frameCSize = 0;
+ zcs->frameDSize = 0;
+
+ /* make sure maxFrameSize has a reasonable value */
+ if (maxFrameSize > ZSTD_SEEKABLE_MAX_FRAME_DECOMPRESSED_SIZE) {
+ return ERROR(compressionParameter_unsupported);
+ }
+
+ zcs->maxFrameSize = maxFrameSize
+ ? maxFrameSize
+ : ZSTD_SEEKABLE_MAX_FRAME_DECOMPRESSED_SIZE;
+
+ zcs->framelog.checksumFlag = checksumFlag;
+ if (zcs->framelog.checksumFlag) {
+ XXH64_reset(&zcs->xxhState, 0);
+ }
+
+ zcs->framelog.seekTablePos = 0;
+ zcs->framelog.seekTableIndex = 0;
+ zcs->writingSeekTable = 0;
+
+ return ZSTD_initCStream(zcs->cstream, compressionLevel);
+}
+
+size_t ZSTD_seekable_logFrame(ZSTD_frameLog* fl,
+ unsigned compressedSize,
+ unsigned decompressedSize,
+ unsigned checksum)
+{
+ if (fl->size == ZSTD_SEEKABLE_MAXFRAMES)
+ return ERROR(frameIndex_tooLarge);
+
+ /* grow the buffer if required */
+ if (fl->size == fl->capacity) {
+ /* exponential size increase for constant amortized runtime */
+ size_t const newCapacity = fl->capacity * 2;
+ framelogEntry_t* const newEntries = realloc(fl->entries,
+ sizeof(framelogEntry_t) * newCapacity);
+
+ if (newEntries == NULL) return ERROR(memory_allocation);
+
+ fl->entries = newEntries;
+ fl->capacity = newCapacity;
+ }
+
+ fl->entries[fl->size] = (framelogEntry_t){
+ compressedSize, decompressedSize, checksum
+ };
+ fl->size++;
+
+ return 0;
+}
+
+size_t ZSTD_seekable_endFrame(ZSTD_seekable_CStream* zcs, ZSTD_outBuffer* output)
+{
+ size_t const prevOutPos = output->pos;
+ /* end the frame */
+ size_t ret = ZSTD_endStream(zcs->cstream, output);
+
+ zcs->frameCSize += output->pos - prevOutPos;
+
+ /* need to flush before doing the rest */
+ if (ret) return ret;
+
+ /* frame done */
+
+ /* store the frame data for later */
+ ret = ZSTD_seekable_logFrame(
+ &zcs->framelog, zcs->frameCSize, zcs->frameDSize,
+ zcs->framelog.checksumFlag
+ ? XXH64_digest(&zcs->xxhState) & 0xFFFFFFFFU
+ : 0);
+ if (ret) return ret;
+
+ /* reset for the next frame */
+ zcs->frameCSize = 0;
+ zcs->frameDSize = 0;
+
+ ZSTD_resetCStream(zcs->cstream, 0);
+ if (zcs->framelog.checksumFlag)
+ XXH64_reset(&zcs->xxhState, 0);
+
+ return 0;
+}
+
+size_t ZSTD_seekable_compressStream(ZSTD_seekable_CStream* zcs, ZSTD_outBuffer* output, ZSTD_inBuffer* input)
+{
+ const BYTE* const inBase = (const BYTE*) input->src + input->pos;
+ size_t inLen = input->size - input->pos;
+
+ inLen = MIN(inLen, (size_t)(zcs->maxFrameSize - zcs->frameDSize));
+
+ /* if we haven't finished flushing the last frame, don't start writing a new one */
+ if (inLen > 0) {
+ ZSTD_inBuffer inTmp = { inBase, inLen, 0 };
+ size_t const prevOutPos = output->pos;
+
+ size_t const ret = ZSTD_compressStream(zcs->cstream, output, &inTmp);
+
+ if (zcs->framelog.checksumFlag) {
+ XXH64_update(&zcs->xxhState, inBase, inTmp.pos);
+ }
+
+ zcs->frameCSize += output->pos - prevOutPos;
+ zcs->frameDSize += inTmp.pos;
+
+ input->pos += inTmp.pos;
+
+ if (ZSTD_isError(ret)) return ret;
+ }
+
+ if (zcs->maxFrameSize == zcs->frameDSize) {
+ /* log the frame and start over */
+ size_t const ret = ZSTD_seekable_endFrame(zcs, output);
+ if (ZSTD_isError(ret)) return ret;
+
+ /* get the client ready for the next frame */
+ return (size_t)zcs->maxFrameSize;
+ }
+
+ return (size_t)(zcs->maxFrameSize - zcs->frameDSize);
+}
+
+static inline size_t ZSTD_seekable_seekTableSize(const ZSTD_frameLog* fl)
+{
+ size_t const sizePerFrame = 8 + (fl->checksumFlag?4:0);
+ size_t const seekTableLen = ZSTD_skippableHeaderSize +
+ sizePerFrame * fl->size +
+ ZSTD_seekTableFooterSize;
+
+ return seekTableLen;
+}
+
+static inline size_t ZSTD_stwrite32(ZSTD_frameLog* fl,
+ ZSTD_outBuffer* output, U32 const value,
+ U32 const offset)
+{
+ if (fl->seekTablePos < offset + 4) {
+ BYTE tmp[4]; /* so that we can work with buffers too small to write a whole word to */
+ size_t const lenWrite =
+ MIN(output->size - output->pos, offset + 4 - fl->seekTablePos);
+ MEM_writeLE32(tmp, value);
+ memcpy((BYTE*)output->dst + output->pos,
+ tmp + (fl->seekTablePos - offset), lenWrite);
+ output->pos += lenWrite;
+ fl->seekTablePos += lenWrite;
+
+ if (lenWrite < 4) return ZSTD_seekable_seekTableSize(fl) - fl->seekTablePos;
+ }
+ return 0;
+}
+
+size_t ZSTD_seekable_writeSeekTable(ZSTD_frameLog* fl, ZSTD_outBuffer* output)
+{
+ /* seekTableIndex: the current index in the table and
+ * seekTableSize: the amount of the table written so far
+ *
+ * This function is written this way so that if it has to return early
+ * because of a small buffer, it can keep going where it left off.
+ */
+
+ size_t const sizePerFrame = 8 + (fl->checksumFlag?4:0);
+ size_t const seekTableLen = ZSTD_seekable_seekTableSize(fl);
+
+ CHECK_Z(ZSTD_stwrite32(fl, output, ZSTD_MAGIC_SKIPPABLE_START | 0xE, 0));
+ CHECK_Z(ZSTD_stwrite32(fl, output, seekTableLen - ZSTD_skippableHeaderSize,
+ 4));
+
+ while (fl->seekTableIndex < fl->size) {
+ CHECK_Z(ZSTD_stwrite32(fl, output,
+ fl->entries[fl->seekTableIndex].cSize,
+ ZSTD_skippableHeaderSize +
+ sizePerFrame * fl->seekTableIndex + 0));
+
+ CHECK_Z(ZSTD_stwrite32(fl, output,
+ fl->entries[fl->seekTableIndex].dSize,
+ ZSTD_skippableHeaderSize +
+ sizePerFrame * fl->seekTableIndex + 4));
+
+ if (fl->checksumFlag) {
+ CHECK_Z(ZSTD_stwrite32(
+ fl, output, fl->entries[fl->seekTableIndex].checksum,
+ ZSTD_skippableHeaderSize +
+ sizePerFrame * fl->seekTableIndex + 8));
+ }
+
+ fl->seekTableIndex++;
+ }
+
+ CHECK_Z(ZSTD_stwrite32(fl, output, fl->size,
+ seekTableLen - ZSTD_seekTableFooterSize));
+
+ if (output->size - output->pos < 1) return seekTableLen - fl->seekTablePos;
+ if (fl->seekTablePos < seekTableLen - 4) {
+ BYTE sfd = 0;
+ sfd |= (fl->checksumFlag) << 7;
+
+ ((BYTE*)output->dst)[output->pos] = sfd;
+ output->pos++;
+ fl->seekTablePos++;
+ }
+
+ CHECK_Z(ZSTD_stwrite32(fl, output, ZSTD_SEEKABLE_MAGICNUMBER,
+ seekTableLen - 4));
+
+ if (fl->seekTablePos != seekTableLen) return ERROR(GENERIC);
+ return 0;
+}
+
+size_t ZSTD_seekable_endStream(ZSTD_seekable_CStream* zcs, ZSTD_outBuffer* output)
+{
+ if (!zcs->writingSeekTable && zcs->frameDSize) {
+ const size_t endFrame = ZSTD_seekable_endFrame(zcs, output);
+ if (ZSTD_isError(endFrame)) return endFrame;
+ /* return an accurate size hint */
+ if (endFrame) return endFrame + ZSTD_seekable_seekTableSize(&zcs->framelog);
+ }
+
+ zcs->writingSeekTable = 1;
+
+ return ZSTD_seekable_writeSeekTable(&zcs->framelog, output);
+}
diff --git a/src/zstd/contrib/seekable_format/zstdseek_decompress.c b/src/zstd/contrib/seekable_format/zstdseek_decompress.c
new file mode 100644
index 00000000..d740e16b
--- /dev/null
+++ b/src/zstd/contrib/seekable_format/zstdseek_decompress.c
@@ -0,0 +1,462 @@
+/*
+ * Copyright (c) 2017-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).
+ * You may select, at your option, one of the above-listed licenses.
+ */
+
+/* *********************************************************
+* Turn on Large Files support (>4GB) for 32-bit Linux/Unix
+***********************************************************/
+#if !defined(__64BIT__) || defined(__MINGW32__) /* No point defining Large file for 64 bit but MinGW-w64 requires it */
+# if !defined(_FILE_OFFSET_BITS)
+# define _FILE_OFFSET_BITS 64 /* turn off_t into a 64-bit type for ftello, fseeko */
+# endif
+# if !defined(_LARGEFILE_SOURCE) /* obsolete macro, replaced with _FILE_OFFSET_BITS */
+# define _LARGEFILE_SOURCE 1 /* Large File Support extension (LFS) - fseeko, ftello */
+# endif
+# if defined(_AIX) || defined(__hpux)
+# define _LARGE_FILES /* Large file support on 32-bits AIX and HP-UX */
+# endif
+#endif
+
+/* ************************************************************
+* Avoid fseek()'s 2GiB barrier with MSVC, MacOS, *BSD, MinGW
+***************************************************************/
+#if defined(_MSC_VER) && _MSC_VER >= 1400
+# define LONG_SEEK _fseeki64
+#elif !defined(__64BIT__) && (PLATFORM_POSIX_VERSION >= 200112L) /* No point defining Large file for 64 bit */
+# define LONG_SEEK fseeko
+#elif defined(__MINGW32__) && !defined(__STRICT_ANSI__) && !defined(__NO_MINGW_LFS) && defined(__MSVCRT__)
+# define LONG_SEEK fseeko64
+#elif defined(_WIN32) && !defined(__DJGPP__)
+# include <windows.h>
+ static int LONG_SEEK(FILE* file, __int64 offset, int origin) {
+ LARGE_INTEGER off;
+ DWORD method;
+ off.QuadPart = offset;
+ if (origin == SEEK_END)
+ method = FILE_END;
+ else if (origin == SEEK_CUR)
+ method = FILE_CURRENT;
+ else
+ method = FILE_BEGIN;
+
+ if (SetFilePointerEx((HANDLE) _get_osfhandle(_fileno(file)), off, NULL, method))
+ return 0;
+ else
+ return -1;
+ }
+#else
+# define LONG_SEEK fseek
+#endif
+
+#include <stdlib.h> /* malloc, free */
+#include <stdio.h> /* FILE* */
+
+#define XXH_STATIC_LINKING_ONLY
+#define XXH_NAMESPACE ZSTD_
+#include "xxhash.h"
+
+#define ZSTD_STATIC_LINKING_ONLY
+#include "zstd.h"
+#include "zstd_errors.h"
+#include "mem.h"
+#include "zstd_seekable.h"
+
+#undef ERROR
+#define ERROR(name) ((size_t)-ZSTD_error_##name)
+
+#define CHECK_IO(f) { int const errcod = (f); if (errcod < 0) return ERROR(seekableIO); }
+
+#undef MIN
+#undef MAX
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+
+/* Special-case callbacks for FILE* and in-memory modes, so that we can treat
+ * them the same way as the advanced API */
+static int ZSTD_seekable_read_FILE(void* opaque, void* buffer, size_t n)
+{
+ size_t const result = fread(buffer, 1, n, (FILE*)opaque);
+ if (result != n) {
+ return -1;
+ }
+ return 0;
+}
+
+static int ZSTD_seekable_seek_FILE(void* opaque, S64 offset, int origin)
+{
+ int const ret = LONG_SEEK((FILE*)opaque, offset, origin);
+ if (ret) return ret;
+ return fflush((FILE*)opaque);
+}
+
+typedef struct {
+ const void *ptr;
+ size_t size;
+ size_t pos;
+} buffWrapper_t;
+
+static int ZSTD_seekable_read_buff(void* opaque, void* buffer, size_t n)
+{
+ buffWrapper_t* buff = (buffWrapper_t*) opaque;
+ if (buff->size + n > buff->pos) return -1;
+ memcpy(buffer, (const BYTE*)buff->ptr + buff->pos, n);
+ buff->pos += n;
+ return 0;
+}
+
+static int ZSTD_seekable_seek_buff(void* opaque, S64 offset, int origin)
+{
+ buffWrapper_t* buff = (buffWrapper_t*) opaque;
+ unsigned long long newOffset;
+ switch (origin) {
+ case SEEK_SET:
+ newOffset = offset;
+ break;
+ case SEEK_CUR:
+ newOffset = (unsigned long long)buff->pos + offset;
+ break;
+ case SEEK_END:
+ newOffset = (unsigned long long)buff->size - offset;
+ break;
+ }
+ if (newOffset < 0 || newOffset > buff->size) {
+ return -1;
+ }
+ buff->pos = newOffset;
+ return 0;
+}
+
+typedef struct {
+ U64 cOffset;
+ U64 dOffset;
+ U32 checksum;
+} seekEntry_t;
+
+typedef struct {
+ seekEntry_t* entries;
+ size_t tableLen;
+
+ int checksumFlag;
+} seekTable_t;
+
+#define SEEKABLE_BUFF_SIZE ZSTD_BLOCKSIZE_ABSOLUTEMAX
+
+struct ZSTD_seekable_s {
+ ZSTD_DStream* dstream;
+ seekTable_t seekTable;
+ ZSTD_seekable_customFile src;
+
+ U64 decompressedOffset;
+ U32 curFrame;
+
+ BYTE inBuff[SEEKABLE_BUFF_SIZE]; /* need to do our own input buffering */
+ BYTE outBuff[SEEKABLE_BUFF_SIZE]; /* so we can efficiently decompress the
+ starts of chunks before we get to the
+ desired section */
+ ZSTD_inBuffer in; /* maintain continuity across ZSTD_seekable_decompress operations */
+ buffWrapper_t buffWrapper; /* for `src.opaque` in in-memory mode */
+
+ XXH64_state_t xxhState;
+};
+
+ZSTD_seekable* ZSTD_seekable_create(void)
+{
+ ZSTD_seekable* zs = malloc(sizeof(ZSTD_seekable));
+
+ if (zs == NULL) return NULL;
+
+ /* also initializes stage to zsds_init */
+ memset(zs, 0, sizeof(*zs));
+
+ zs->dstream = ZSTD_createDStream();
+ if (zs->dstream == NULL) {
+ free(zs);
+ return NULL;
+ }
+
+ return zs;
+}
+
+size_t ZSTD_seekable_free(ZSTD_seekable* zs)
+{
+ if (zs == NULL) return 0; /* support free on null */
+ ZSTD_freeDStream(zs->dstream);
+ free(zs->seekTable.entries);
+ free(zs);
+
+ return 0;
+}
+
+/** ZSTD_seekable_offsetToFrameIndex() :
+ * Performs a binary search to find the last frame with a decompressed offset
+ * <= pos
+ * @return : the frame's index */
+U32 ZSTD_seekable_offsetToFrameIndex(ZSTD_seekable* const zs, U64 pos)
+{
+ U32 lo = 0;
+ U32 hi = zs->seekTable.tableLen;
+
+ if (pos >= zs->seekTable.entries[zs->seekTable.tableLen].dOffset) {
+ return zs->seekTable.tableLen;
+ }
+
+ while (lo + 1 < hi) {
+ U32 const mid = lo + ((hi - lo) >> 1);
+ if (zs->seekTable.entries[mid].dOffset <= pos) {
+ lo = mid;
+ } else {
+ hi = mid;
+ }
+ }
+ return lo;
+}
+
+U32 ZSTD_seekable_getNumFrames(ZSTD_seekable* const zs)
+{
+ return zs->seekTable.tableLen;
+}
+
+U64 ZSTD_seekable_getFrameCompressedOffset(ZSTD_seekable* const zs, U32 frameIndex)
+{
+ if (frameIndex >= zs->seekTable.tableLen) return ZSTD_SEEKABLE_FRAMEINDEX_TOOLARGE;
+ return zs->seekTable.entries[frameIndex].cOffset;
+}
+
+U64 ZSTD_seekable_getFrameDecompressedOffset(ZSTD_seekable* const zs, U32 frameIndex)
+{
+ if (frameIndex >= zs->seekTable.tableLen) return ZSTD_SEEKABLE_FRAMEINDEX_TOOLARGE;
+ return zs->seekTable.entries[frameIndex].dOffset;
+}
+
+size_t ZSTD_seekable_getFrameCompressedSize(ZSTD_seekable* const zs, U32 frameIndex)
+{
+ if (frameIndex >= zs->seekTable.tableLen) return ERROR(frameIndex_tooLarge);
+ return zs->seekTable.entries[frameIndex + 1].cOffset -
+ zs->seekTable.entries[frameIndex].cOffset;
+}
+
+size_t ZSTD_seekable_getFrameDecompressedSize(ZSTD_seekable* const zs, U32 frameIndex)
+{
+ if (frameIndex > zs->seekTable.tableLen) return ERROR(frameIndex_tooLarge);
+ return zs->seekTable.entries[frameIndex + 1].dOffset -
+ zs->seekTable.entries[frameIndex].dOffset;
+}
+
+static size_t ZSTD_seekable_loadSeekTable(ZSTD_seekable* zs)
+{
+ int checksumFlag;
+ ZSTD_seekable_customFile src = zs->src;
+ /* read the footer, fixed size */
+ CHECK_IO(src.seek(src.opaque, -(int)ZSTD_seekTableFooterSize, SEEK_END));
+ CHECK_IO(src.read(src.opaque, zs->inBuff, ZSTD_seekTableFooterSize));
+
+ if (MEM_readLE32(zs->inBuff + 5) != ZSTD_SEEKABLE_MAGICNUMBER) {
+ return ERROR(prefix_unknown);
+ }
+
+ { BYTE const sfd = zs->inBuff[4];
+ checksumFlag = sfd >> 7;
+
+ /* check reserved bits */
+ if ((checksumFlag >> 2) & 0x1f) {
+ return ERROR(corruption_detected);
+ }
+ }
+
+ { U32 const numFrames = MEM_readLE32(zs->inBuff);
+ U32 const sizePerEntry = 8 + (checksumFlag?4:0);
+ U32 const tableSize = sizePerEntry * numFrames;
+ U32 const frameSize = tableSize + ZSTD_seekTableFooterSize + ZSTD_skippableHeaderSize;
+
+ U32 remaining = frameSize - ZSTD_seekTableFooterSize; /* don't need to re-read footer */
+ {
+ U32 const toRead = MIN(remaining, SEEKABLE_BUFF_SIZE);
+
+ CHECK_IO(src.seek(src.opaque, -(S64)frameSize, SEEK_END));
+ CHECK_IO(src.read(src.opaque, zs->inBuff, toRead));
+
+ remaining -= toRead;
+ }
+
+ if (MEM_readLE32(zs->inBuff) != (ZSTD_MAGIC_SKIPPABLE_START | 0xE)) {
+ return ERROR(prefix_unknown);
+ }
+ if (MEM_readLE32(zs->inBuff+4) + ZSTD_skippableHeaderSize != frameSize) {
+ return ERROR(prefix_unknown);
+ }
+
+ { /* Allocate an extra entry at the end so that we can do size
+ * computations on the last element without special case */
+ seekEntry_t* entries = (seekEntry_t*)malloc(sizeof(seekEntry_t) * (numFrames + 1));
+ const BYTE* tableBase = zs->inBuff + ZSTD_skippableHeaderSize;
+
+ U32 idx = 0;
+ U32 pos = 8;
+
+
+ U64 cOffset = 0;
+ U64 dOffset = 0;
+
+ if (!entries) {
+ free(entries);
+ return ERROR(memory_allocation);
+ }
+
+ /* compute cumulative positions */
+ for (; idx < numFrames; idx++) {
+ if (pos + sizePerEntry > SEEKABLE_BUFF_SIZE) {
+ U32 const toRead = MIN(remaining, SEEKABLE_BUFF_SIZE);
+ U32 const offset = SEEKABLE_BUFF_SIZE - pos;
+ memmove(zs->inBuff, zs->inBuff + pos, offset); /* move any data we haven't read yet */
+ CHECK_IO(src.read(src.opaque, zs->inBuff+offset, toRead));
+ remaining -= toRead;
+ pos = 0;
+ }
+ entries[idx].cOffset = cOffset;
+ entries[idx].dOffset = dOffset;
+
+ cOffset += MEM_readLE32(zs->inBuff + pos);
+ pos += 4;
+ dOffset += MEM_readLE32(zs->inBuff + pos);
+ pos += 4;
+ if (checksumFlag) {
+ entries[idx].checksum = MEM_readLE32(zs->inBuff + pos);
+ pos += 4;
+ }
+ }
+ entries[numFrames].cOffset = cOffset;
+ entries[numFrames].dOffset = dOffset;
+
+ zs->seekTable.entries = entries;
+ zs->seekTable.tableLen = numFrames;
+ zs->seekTable.checksumFlag = checksumFlag;
+ return 0;
+ }
+ }
+}
+
+size_t ZSTD_seekable_initBuff(ZSTD_seekable* zs, const void* src, size_t srcSize)
+{
+ zs->buffWrapper = (buffWrapper_t){src, srcSize, 0};
+ { ZSTD_seekable_customFile srcFile = {&zs->buffWrapper,
+ &ZSTD_seekable_read_buff,
+ &ZSTD_seekable_seek_buff};
+ return ZSTD_seekable_initAdvanced(zs, srcFile); }
+}
+
+size_t ZSTD_seekable_initFile(ZSTD_seekable* zs, FILE* src)
+{
+ ZSTD_seekable_customFile srcFile = {src, &ZSTD_seekable_read_FILE,
+ &ZSTD_seekable_seek_FILE};
+ return ZSTD_seekable_initAdvanced(zs, srcFile);
+}
+
+size_t ZSTD_seekable_initAdvanced(ZSTD_seekable* zs, ZSTD_seekable_customFile src)
+{
+ zs->src = src;
+
+ { const size_t seekTableInit = ZSTD_seekable_loadSeekTable(zs);
+ if (ZSTD_isError(seekTableInit)) return seekTableInit; }
+
+ zs->decompressedOffset = (U64)-1;
+ zs->curFrame = (U32)-1;
+
+ { const size_t dstreamInit = ZSTD_initDStream(zs->dstream);
+ if (ZSTD_isError(dstreamInit)) return dstreamInit; }
+ return 0;
+}
+
+size_t ZSTD_seekable_decompress(ZSTD_seekable* zs, void* dst, size_t len, U64 offset)
+{
+ U32 targetFrame = ZSTD_seekable_offsetToFrameIndex(zs, offset);
+ do {
+ /* check if we can continue from a previous decompress job */
+ if (targetFrame != zs->curFrame || offset != zs->decompressedOffset) {
+ zs->decompressedOffset = zs->seekTable.entries[targetFrame].dOffset;
+ zs->curFrame = targetFrame;
+
+ CHECK_IO(zs->src.seek(zs->src.opaque,
+ zs->seekTable.entries[targetFrame].cOffset,
+ SEEK_SET));
+ zs->in = (ZSTD_inBuffer){zs->inBuff, 0, 0};
+ XXH64_reset(&zs->xxhState, 0);
+ ZSTD_resetDStream(zs->dstream);
+ }
+
+ while (zs->decompressedOffset < offset + len) {
+ size_t toRead;
+ ZSTD_outBuffer outTmp;
+ size_t prevOutPos;
+ if (zs->decompressedOffset < offset) {
+ /* dummy decompressions until we get to the target offset */
+ outTmp = (ZSTD_outBuffer){zs->outBuff, MIN(SEEKABLE_BUFF_SIZE, offset - zs->decompressedOffset), 0};
+ } else {
+ outTmp = (ZSTD_outBuffer){dst, len, zs->decompressedOffset - offset};
+ }
+
+ prevOutPos = outTmp.pos;
+ toRead = ZSTD_decompressStream(zs->dstream, &outTmp, &zs->in);
+ if (ZSTD_isError(toRead)) {
+ return toRead;
+ }
+
+ if (zs->seekTable.checksumFlag) {
+ XXH64_update(&zs->xxhState, (BYTE*)outTmp.dst + prevOutPos,
+ outTmp.pos - prevOutPos);
+ }
+ zs->decompressedOffset += outTmp.pos - prevOutPos;
+
+ if (toRead == 0) {
+ /* frame complete */
+
+ /* verify checksum */
+ if (zs->seekTable.checksumFlag &&
+ (XXH64_digest(&zs->xxhState) & 0xFFFFFFFFU) !=
+ zs->seekTable.entries[targetFrame].checksum) {
+ return ERROR(corruption_detected);
+ }
+
+ if (zs->decompressedOffset < offset + len) {
+ /* go back to the start and force a reset of the stream */
+ targetFrame = ZSTD_seekable_offsetToFrameIndex(zs, zs->decompressedOffset);
+ }
+ break;
+ }
+
+ /* read in more data if we're done with this buffer */
+ if (zs->in.pos == zs->in.size) {
+ toRead = MIN(toRead, SEEKABLE_BUFF_SIZE);
+ CHECK_IO(zs->src.read(zs->src.opaque, zs->inBuff, toRead));
+ zs->in.size = toRead;
+ zs->in.pos = 0;
+ }
+ }
+ } while (zs->decompressedOffset != offset + len);
+
+ return len;
+}
+
+size_t ZSTD_seekable_decompressFrame(ZSTD_seekable* zs, void* dst, size_t dstSize, U32 frameIndex)
+{
+ if (frameIndex >= zs->seekTable.tableLen) {
+ return ERROR(frameIndex_tooLarge);
+ }
+
+ {
+ size_t const decompressedSize =
+ zs->seekTable.entries[frameIndex + 1].dOffset -
+ zs->seekTable.entries[frameIndex].dOffset;
+ if (dstSize < decompressedSize) {
+ return ERROR(dstSize_tooSmall);
+ }
+ return ZSTD_seekable_decompress(
+ zs, dst, decompressedSize,
+ zs->seekTable.entries[frameIndex].dOffset);
+ }
+}