zstd/examples/streaming_compression.c
2016-09-20 11:54:29 +02:00

131 lines
4.2 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
#define ZSTD_STATIC_LINKING_ONLY // streaming API defined as "experimental" for the time being
#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 compressFile_orDie(const char* fname, const char* outName, int cLevel)
{
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_CStream* const cstream = ZSTD_createCStream();
if (cstream==NULL) { fprintf(stderr, "ZSTD_createCStream() error \n"); exit(10); }
size_t const initResult = ZSTD_initCStream(cstream, cLevel);
if (ZSTD_isError(initResult)) { fprintf(stderr, "ZSTD_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_compressStream(cstream, &output , &input); /* toRead is guaranteed to be <= ZSTD_CStreamInSize() */
if (ZSTD_isError(toRead)) { fprintf(stderr, "ZSTD_compressStream() error : %s \n", ZSTD_getErrorName(toRead)); exit(12); }
if (toRead > buffInSize) toRead = buffInSize; /* Safely handle when `buffInSize` is manually changed to a smaller value */
fwrite_orDie(buffOut, output.pos, fout);
}
}
ZSTD_outBuffer output = { buffOut, buffOutSize, 0 };
size_t const remainingToFlush = ZSTD_endStream(cstream, &output); /* close frame */
if (remainingToFlush) { fprintf(stderr, "not fully flushed"); exit(13); }
fwrite_orDie(buffOut, output.pos, fout);
ZSTD_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];
const char* const inFilename = argv[1];
if (argc!=2) {
printf("wrong arguments\n");
printf("usage:\n");
printf("%s FILE\n", exeName);
return 1;
}
const char* const outFilename = createOutFilename_orDie(inFilename);
compressFile_orDie(inFilename, outFilename, 1);
return 0;
}