zstd/examples/dictionary_compression.c
2016-09-09 19:33:56 +02:00

156 lines
4.3 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> // printf
#include <string.h> // strerror
#include <errno.h> // errno
#include <sys/stat.h> // stat
#include <zstd.h> // presumes zstd library is installed
static off_t fsize_orDie(const char *filename)
{
struct stat st;
if (stat(filename, &st) == 0) return st.st_size;
/* error */
perror(filename);
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(2);
}
static void* malloc_orDie(size_t size)
{
void* const buff = malloc(size);
if (buff) return buff;
/* error */
perror("malloc");
exit(3);
}
static void* loadFile_orDie(const char* fileName, size_t* size)
{
off_t const buffSize = fsize_orDie(fileName);
FILE* const inFile = fopen_orDie(fileName, "rb");
void* const buffer = malloc_orDie(buffSize);
size_t const readSize = fread(buffer, 1, buffSize, inFile);
if (readSize != (size_t)buffSize) {
fprintf(stderr, "fread: %s : %s \n", fileName, strerror(errno));
exit(4);
}
fclose(inFile);
*size = buffSize;
return buffer;
}
static void saveFile_orDie(const char* fileName, const void* buff, size_t buffSize)
{
FILE* const oFile = fopen_orDie(fileName, "wb");
size_t const wSize = fwrite(buff, 1, buffSize, oFile);
if (wSize != (size_t)buffSize) {
fprintf(stderr, "fwrite: %s : %s \n", fileName, strerror(errno));
exit(5);
}
if (fclose(oFile)) {
perror(fileName);
exit(6);
}
}
/* createDict() :
`dictFileName` is supposed to have been created using `zstd --train` */
static ZSTD_CDict* createCDict_orDie(const char* dictFileName, int cLevel)
{
size_t dictSize;
printf("loading dictionary %s \n", dictFileName);
void* const dictBuffer = loadFile_orDie(dictFileName, &dictSize);
ZSTD_CDict* const cdict = ZSTD_createCDict(dictBuffer, dictSize, cLevel);
if (!cdict) {
fprintf(stderr, "ZSTD_createCDict error \n");
exit(7);
}
free(dictBuffer);
return cdict;
}
static void compress(const char* fname, const char* oname, const ZSTD_CDict* cdict)
{
size_t fSize;
void* const fBuff = loadFile_orDie(fname, &fSize);
size_t const cBuffSize = ZSTD_compressBound(fSize);
void* const cBuff = malloc_orDie(cBuffSize);
ZSTD_CCtx* const cctx = ZSTD_createCCtx();
if (cctx==NULL) { fprintf(stderr, "ZSTD_createCCtx() error \n"); exit(10); }
size_t const cSize = ZSTD_compress_usingCDict(cctx, cBuff, cBuffSize, fBuff, fSize, cdict);
if (ZSTD_isError(cSize)) {
fprintf(stderr, "error compressing %s : %s \n", fname, ZSTD_getErrorName(cSize));
exit(7);
}
saveFile_orDie(oname, cBuff, cSize);
/* success */
printf("%25s : %6u -> %7u - %s \n", fname, (unsigned)fSize, (unsigned)cSize, oname);
ZSTD_freeCCtx(cctx); /* never fails */
free(fBuff);
free(cBuff);
}
static 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 (char*)outSpace;
}
int main(int argc, const char** argv)
{
const char* const exeName = argv[0];
int const cLevel = 3;
if (argc<3) {
fprintf(stderr, "wrong arguments\n");
fprintf(stderr, "usage:\n");
fprintf(stderr, "%s [FILES] dictionary\n", exeName);
return 1;
}
/* load dictionary only once */
const char* const dictName = argv[argc-1];
ZSTD_CDict* const dictPtr = createCDict_orDie(dictName, cLevel);
int u;
for (u=1; u<argc-1; u++) {
const char* inFilename = argv[u];
char* const outFilename = createOutFilename_orDie(inFilename);
compress(inFilename, outFilename, dictPtr);
free(outFilename);
}
ZSTD_freeCDict(dictPtr);
printf("All %u files compressed. \n", argc-2);
return 0;
}