githubmirror/zstd

examples/simple_decompression.c

66 строк2 KB

Yi Jin

break loadFile_orDie() into 2: loadFile_orDie() loads file into a pre-allocated memory buffer, mallocAndLoadFile_orDie() allocates memory first, then calls loadFile_orDie()

18 дек 2018, 03:54

18 дек 2018, 03:54bc4dc60

/*
 * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
 * 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 <stdlib.h>    // malloc, exit
#include <stdio.h>     // printf
#include <string.h>    // strerror
#include <errno.h>     // errno
#include <sys/stat.h>  // stat
#define ZSTD_STATIC_LINKING_ONLY   // ZSTD_findDecompressedSize
#include <zstd.h>      // presumes zstd library is installed
#include "utils.h"

static void decompress(const char* fname)
{
    size_t cSize;
    void* const cBuff = mallocAndLoadFile_orDie(fname, &cSize);
    unsigned long long const rSize = ZSTD_findDecompressedSize(cBuff, cSize);
    if (rSize==ZSTD_CONTENTSIZE_ERROR) {
        fprintf(stderr, "%s : it was not compressed by zstd.\n", fname);
        exit(5);
    } else if (rSize==ZSTD_CONTENTSIZE_UNKNOWN) {
        fprintf(stderr,
                "%s : original size unknown. Use streaming decompression instead.\n", fname);
        exit(6);
    }

    void* const rBuff = malloc_orDie((size_t)rSize);

    size_t const dSize = ZSTD_decompress(rBuff, rSize, cBuff, cSize);

    if (dSize != rSize) {
        fprintf(stderr, "error decoding %s : %s \n", fname, ZSTD_getErrorName(dSize));
        exit(7);
    }

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

    free(rBuff);
    free(cBuff);
}

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;
    }

    decompress(argv[1]);

    printf("%s correctly decoded (in memory). \n", argv[1]);

    return 0;
}