1 /*
2 * Copyright (c) 2016-2020, 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
decompress(const char * fname)16 static 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
main(int argc,const char ** argv)49 int 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