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/*
* Copyright (c) 2016-2021, 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.
*/
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#define ZSTD_STATIC_LINKING_ONLY
#include "util.h"
#include "zstd.h"
#define CHECK(cond, ...) \
do { \
if (!(cond)) { \
fprintf(stderr, "%s:%d CHECK(%s) failed: ", __FILE__, __LINE__, #cond); \
fprintf(stderr, "" __VA_ARGS__); \
fprintf(stderr, "\n"); \
exit(1); \
} \
} while (0)
static void usage(char const *program) {
fprintf(stderr, "USAGE: %s FILE.zst PREFIX\n", program);
fprintf(stderr, "FILE.zst: A zstd compressed file with multiple frames\n");
fprintf(stderr, "PREFIX: The output prefix. Uncompressed files will be "
"created named ${PREFIX}0 ${PREFIX}1...\n\n");
fprintf(stderr, "This program takes concatenated zstd frames and "
"decompresses them into individual files.\n");
fprintf(stderr, "E.g. files created with a command like: zstd -r directory "
"-o file.zst\n");
}
typedef struct {
char *data;
size_t size;
size_t frames;
size_t maxFrameSize;
} ZstdFrames;
static ZstdFrames readFile(char const *fileName) {
U64 const fileSize = UTIL_getFileSize(fileName);
CHECK(fileSize != UTIL_FILESIZE_UNKNOWN, "Unknown file size!");
char *const data = (char *)malloc(fileSize);
CHECK(data != NULL, "Allocation failed");
FILE *file = fopen(fileName, "rb");
CHECK(file != NULL, "fopen failed");
size_t const readSize = fread(data, 1, fileSize, file);
CHECK(readSize == fileSize, "fread failed");
fclose(file);
ZstdFrames frames;
frames.data = (char *)data;
frames.size = fileSize;
frames.frames = 0;
size_t index;
size_t maxFrameSize = 0;
for (index = 0; index < fileSize;) {
size_t const frameSize =
ZSTD_findFrameCompressedSize(data + index, fileSize - index);
CHECK(!ZSTD_isError(frameSize), "Bad zstd frame: %s",
ZSTD_getErrorName(frameSize));
if (frameSize > maxFrameSize)
maxFrameSize = frameSize;
frames.frames += 1;
index += frameSize;
}
CHECK(index == fileSize, "Zstd file corrupt!");
frames.maxFrameSize = maxFrameSize;
return frames;
}
static int computePadding(size_t numFrames) {
return snprintf(NULL, 0, "%u", (unsigned)numFrames);
}
int main(int argc, char **argv) {
if (argc != 3) {
usage(argv[0]);
exit(1);
}
char const *const zstdFile = argv[1];
char const *const prefix = argv[2];
ZstdFrames frames = readFile(zstdFile);
if (frames.frames <= 1) {
fprintf(
stderr,
"%s only has %u zstd frame. Simply use `zstd -d` to decompress it.\n",
zstdFile, (unsigned)frames.frames);
exit(1);
}
int const padding = computePadding(frames.frames - 1);
size_t const outFileNameSize = strlen(prefix) + padding + 1;
char* outFileName = malloc(outFileNameSize);
CHECK(outFileName != NULL, "Allocation failure");
size_t const bufferSize = 128 * 1024;
void *buffer = malloc(bufferSize);
CHECK(buffer != NULL, "Allocation failure");
ZSTD_DCtx* dctx = ZSTD_createDCtx();
CHECK(dctx != NULL, "Allocation failure");
fprintf(stderr, "Recovering %u files...\n", (unsigned)frames.frames);
size_t index;
size_t frame = 0;
for (index = 0; index < frames.size; ++frame) {
size_t const frameSize =
ZSTD_findFrameCompressedSize(frames.data + index, frames.size - index);
int const ret = snprintf(outFileName, outFileNameSize, "%s%0*u", prefix, padding, (unsigned)frame);
CHECK(ret >= 0 && (size_t)ret <= outFileNameSize, "snprintf failed!");
FILE* outFile = fopen(outFileName, "wb");
CHECK(outFile != NULL, "fopen failed");
ZSTD_DCtx_reset(dctx, ZSTD_reset_session_only);
ZSTD_inBuffer in = {frames.data + index, frameSize, 0};
while (in.pos < in.size) {
ZSTD_outBuffer out = {buffer, bufferSize, 0};
CHECK(!ZSTD_isError(ZSTD_decompressStream(dctx, &out, &in)), "decompression failed");
size_t const writeSize = fwrite(out.dst, 1, out.pos, outFile);
CHECK(writeSize == out.pos, "fwrite failed");
}
fclose(outFile);
fprintf(stderr, "Recovered %s\n", outFileName);
index += frameSize;
}
fprintf(stderr, "Complete\n");
free(outFileName);
ZSTD_freeDCtx(dctx);
free(buffer);
free(frames.data);
return 0;
}
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