zstd/examples/streaming_decompression.c
2018-12-06 22:42:19 -05:00

71 lines
2.6 KiB
C

/*
* 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).
* You may select, at your option, one of the above-listed licenses.
*/
#include <stdlib.h> // malloc, exit
#include <stdio.h> // fprintf, perror, feof
#include <string.h> // strerror
#include <errno.h> // errno
#include <zstd.h> // presumes zstd library is installed
#include "utils.h"
static void decompressFile_orDie(const char* fname)
{
FILE* const fin = fopen_orDie(fname, "rb");
size_t const buffInSize = ZSTD_DStreamInSize();
void* const buffIn = malloc_orDie(buffInSize);
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_DStream* const dstream = ZSTD_createDStream();
if (dstream==NULL) { fprintf(stderr, "ZSTD_createDStream() error \n"); exit(10); }
/* In more complex scenarios, a file may consist of multiple appended frames (ex : pzstd).
* The following example decompresses only the first frame.
* It is compatible with other provided streaming examples */
size_t const initResult = ZSTD_initDStream(dstream);
if (ZSTD_isError(initResult)) { fprintf(stderr, "ZSTD_initDStream() error : %s \n", ZSTD_getErrorName(initResult)); exit(11); }
size_t read, toRead = initResult;
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_decompressStream(dstream, &output , &input); /* toRead : size of next compressed block */
if (ZSTD_isError(toRead)) { fprintf(stderr, "ZSTD_decompressStream() error : %s \n", ZSTD_getErrorName(toRead)); exit(12); }
fwrite_orDie(buffOut, output.pos, fout);
}
}
ZSTD_freeDStream(dstream);
fclose_orDie(fin);
fclose_orDie(fout);
free(buffIn);
free(buffOut);
}
int main(int argc, const char** argv)
{
const char* const exeName = argv[0];
if (argc!=2) {
fprintf(stderr, "wrong arguments\n");
fprintf(stderr, "usage:\n");
fprintf(stderr, "%s FILE\n", exeName);
return 1;
}
const char* const inFilename = argv[1];
decompressFile_orDie(inFilename);
return 0;
}