1/*
2 * Copyright (c) Yann Collet, Facebook, Inc.
3 * All rights reserved.
4 *
5 * This source code is licensed under both the BSD-style license (found in the
6 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
7 * in the COPYING file in the root directory of this source tree).
8 * You may select, at your option, one of the above-listed licenses.
9 */
10
11#include <stdio.h>     // printf
12#include <stdlib.h>    // free
13#include <zstd.h>      // presumes zstd library is installed
14#include "common.h"    // Helper functions, CHECK(), and CHECK_ZSTD()
15
16static void decompress(const char* fname)
17{
18    size_t cSize;
19    void* const cBuff = mallocAndLoadFile_orDie(fname, &cSize);
20    /* Read the content size from the frame header. For simplicity we require
21     * that it is always present. By default, zstd will write the content size
22     * in the header when it is known. If you can't guarantee that the frame
23     * content size is always written into the header, either use streaming
24     * decompression, or ZSTD_decompressBound().
25     */
26    unsigned long long const rSize = ZSTD_getFrameContentSize(cBuff, cSize);
27    CHECK(rSize != ZSTD_CONTENTSIZE_ERROR, "%s: not compressed by zstd!", fname);
28    CHECK(rSize != ZSTD_CONTENTSIZE_UNKNOWN, "%s: original size unknown!", fname);
29
30    void* const rBuff = malloc_orDie((size_t)rSize);
31
32    /* Decompress.
33     * If you are doing many decompressions, you may want to reuse the context
34     * and use ZSTD_decompressDCtx(). If you want to set advanced parameters,
35     * use ZSTD_DCtx_setParameter().
36     */
37    size_t const dSize = ZSTD_decompress(rBuff, rSize, cBuff, cSize);
38    CHECK_ZSTD(dSize);
39    /* When zstd knows the content size, it will error if it doesn't match. */
40    CHECK(dSize == rSize, "Impossible because zstd will check this condition!");
41
42    /* success */
43    printf("%25s : %6u -> %7u \n", fname, (unsigned)cSize, (unsigned)rSize);
44
45    free(rBuff);
46    free(cBuff);
47}
48
49int main(int argc, const char** argv)
50{
51    const char* const exeName = argv[0];
52
53    if (argc!=2) {
54        printf("wrong arguments\n");
55        printf("usage:\n");
56        printf("%s FILE\n", exeName);
57        return 1;
58    }
59
60    decompress(argv[1]);
61
62    printf("%s correctly decoded (in memory). \n", argv[1]);
63
64    return 0;
65}
66