examples/simple_compression.c

/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 * 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 <stdio.h>     // printf
#include <stdlib.h>    // free
#include <string.h>    // strlen, strcat, memset
#include <zstd.h>      // presumes zstd library is installed
#include "common.h"    // Helper functions, CHECK(), and CHECK_ZSTD()

static void compress_orDie(const char* fname, const char* oname)
{
    size_t fSize;
    void* const fBuff = mallocAndLoadFile_orDie(fname, &fSize);
    size_t const cBuffSize = ZSTD_compressBound(fSize);
    void* const cBuff = malloc_orDie(cBuffSize);

    /* Compress.
     * If you are doing many compressions, you may want to reuse the context.
     * See the multiple_simple_compression.c example.
     */
    size_t const cSize = ZSTD_compress(cBuff, cBuffSize, fBuff, fSize, 1);
    CHECK_ZSTD(cSize);

    saveFile_orDie(oname, cBuff, cSize);

    /* success */
    printf("%25s : %6u -> %7u - %s \n", fname, (unsigned)fSize, (unsigned)cSize, oname);

    free(fBuff);
    free(cBuff);
}

static 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 (char*)outSpace;
}

int main(int argc, const char** argv)
{
    const char* const exeName = argv[0];

    if (argc!=2) {
        printf("wrong arguments\n");
        printf("usage:\n");
        printf("%s FILE\n", exeName);
        return 1;
    }

    const char* const inFilename = argv[1];

    char* const outFilename = createOutFilename_orDie(inFilename);
    compress_orDie(inFilename, outFilename);
    free(outFilename);
    return 0;
}