zstd/examples/streaming_decompression.c
2016-09-08 19:39:00 +02:00

111 lines
3.1 KiB
C

/**
* Copyright 2016-present, Yann Collet, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the license found in the
* LICENSE-examples 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
#include <zstd.h> // presumes zstd library is installed
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 decompressFile_orDie(const char* fname)
{
FILE* const fin = fopen_orDie(fname, "rb");
size_t const buffInSize = ZSTD_DStreamInSize();
void* const buffIn = malloc_orDie(buffInSize);
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);
FILE* const fout = stdout;
ZSTD_DStream* const dstream = ZSTD_createDStream();
if (dstream==NULL) { fprintf(stderr, "ZSTD_createDStream() error \n"); exit(10); }
size_t const initResult = ZSTD_initDStream(dstream);
if (ZSTD_isError(initResult)) { fprintf(stderr, "ZSTD_initDStream() error \n"); exit(11); }
size_t toRead = initResult;
size_t read;
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 */
fwrite_orDie(buffOut, output.pos, fout);
}
}
fclose_orDie(fin);
fclose_orDie(fout);
free(buffIn);
free(buffOut);
}
int main(int argc, const char** argv)
{
const char* const exeName = argv[0];
const char* const inFilename = argv[1];
if (argc!=2) {
fprintf(stderr, "wrong arguments\n");
fprintf(stderr, "usage:\n");
fprintf(stderr, "%s FILE\n", exeName);
return 1;
}
decompressFile_orDie(inFilename);
return 0;
}