zstd/examples/simple_compression.c
2017-02-13 21:12:59 -06:00

133 lines
3.5 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, free, exit
#include <stdio.h> // fprintf, perror, fopen, etc.
#include <string.h> // strlen, strcat, memset, 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(NULL);
exit(3);
}
static void* loadFile_orDie(const char* fileName, size_t* size)
{
off_t const fileSize = fsize_orDie(fileName);
size_t const buffSize = (size_t)fileSize;
if ((off_t)buffSize < fileSize) { /* narrowcast overflow */
fprintf(stderr, "%s : filesize too large \n", fileName);
exit(4);
}
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(5);
}
fclose(inFile); /* can't fail, read only */
*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(6);
}
if (fclose(oFile)) {
perror(fileName);
exit(7);
}
}
static void compress_orDie(const char* fname, const char* oname)
{
size_t fSize;
void* const fBuff = loadFile_orDie(fname, &fSize);
size_t const cBuffSize = ZSTD_compressBound(fSize);
void* const cBuff = malloc_orDie(cBuffSize);
size_t const cSize = ZSTD_compress(cBuff, cBuffSize, fBuff, fSize, 1);
if (ZSTD_isError(cSize)) {
fprintf(stderr, "error compressing %s : %s \n", fname, ZSTD_getErrorName(cSize));
exit(8);
}
saveFile_orDie(oname, cBuff, cSize);
/* success */
printf("%25s : %6u -> %7u - %s \n", fname, (unsigned)fSize, (unsigned)cSize, oname);
free(fBuff);
free(cBuff);
}
static const char* createOutFilename_orDie(const char* filename)
{
size_t const inL = strlen(filename);
size_t const outL = inL + 5;
void* const 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);
compress_orDie(inFilename, outFilename);
free(outFilename);
return 0;
}