648db22b |
1 | /* |
2 | * Copyright (c) Meta Platforms, Inc. and affiliates. |
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 | |
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 | |
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 | } |