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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 | /* This example deals with Dictionary compression, |
12 | * its counterpart is `examples/dictionary_decompression.c` . |
13 | * These examples presume that a dictionary already exists. |
14 | * The main method to create a dictionary is `zstd --train`, |
15 | * look at the CLI documentation for details. |
16 | * Another possible method is to employ dictionary training API, |
17 | * published in `lib/zdict.h` . |
18 | **/ |
19 | |
20 | #include <stdio.h> // printf |
21 | #include <stdlib.h> // free |
22 | #include <string.h> // memset, strcat |
23 | #include <zstd.h> // presumes zstd library is installed |
24 | #include "common.h" // Helper functions, CHECK(), and CHECK_ZSTD() |
25 | |
26 | /* createDict() : |
27 | ** `dictFileName` is supposed already created using `zstd --train` */ |
28 | static ZSTD_CDict* createCDict_orDie(const char* dictFileName, int cLevel) |
29 | { |
30 | size_t dictSize; |
31 | printf("loading dictionary %s \n", dictFileName); |
32 | void* const dictBuffer = mallocAndLoadFile_orDie(dictFileName, &dictSize); |
33 | ZSTD_CDict* const cdict = ZSTD_createCDict(dictBuffer, dictSize, cLevel); |
34 | CHECK(cdict != NULL, "ZSTD_createCDict() failed!"); |
35 | free(dictBuffer); |
36 | return cdict; |
37 | } |
38 | |
39 | |
40 | static void compress(const char* fname, const char* oname, const ZSTD_CDict* cdict) |
41 | { |
42 | size_t fSize; |
43 | void* const fBuff = mallocAndLoadFile_orDie(fname, &fSize); |
44 | size_t const cBuffSize = ZSTD_compressBound(fSize); |
45 | void* const cBuff = malloc_orDie(cBuffSize); |
46 | |
47 | /* Compress using the dictionary. |
48 | * This function writes the dictionary id, and content size into the header. |
49 | * But, it doesn't use a checksum. You can control these options using the |
50 | * advanced API: ZSTD_CCtx_setParameter(), ZSTD_CCtx_refCDict(), |
51 | * and ZSTD_compress2(). |
52 | */ |
53 | ZSTD_CCtx* const cctx = ZSTD_createCCtx(); |
54 | CHECK(cctx != NULL, "ZSTD_createCCtx() failed!"); |
55 | size_t const cSize = ZSTD_compress_usingCDict(cctx, cBuff, cBuffSize, fBuff, fSize, cdict); |
56 | CHECK_ZSTD(cSize); |
57 | |
58 | saveFile_orDie(oname, cBuff, cSize); |
59 | |
60 | /* success */ |
61 | printf("%25s : %6u -> %7u - %s \n", fname, (unsigned)fSize, (unsigned)cSize, oname); |
62 | |
63 | ZSTD_freeCCtx(cctx); /* never fails */ |
64 | free(fBuff); |
65 | free(cBuff); |
66 | } |
67 | |
68 | |
69 | static char* createOutFilename_orDie(const char* filename) |
70 | { |
71 | size_t const inL = strlen(filename); |
72 | size_t const outL = inL + 5; |
73 | void* outSpace = malloc_orDie(outL); |
74 | memset(outSpace, 0, outL); |
75 | strcat(outSpace, filename); |
76 | strcat(outSpace, ".zst"); |
77 | return (char*)outSpace; |
78 | } |
79 | |
80 | int main(int argc, const char** argv) |
81 | { |
82 | const char* const exeName = argv[0]; |
83 | int const cLevel = 3; |
84 | |
85 | if (argc<3) { |
86 | fprintf(stderr, "wrong arguments\n"); |
87 | fprintf(stderr, "usage:\n"); |
88 | fprintf(stderr, "%s [FILES] dictionary\n", exeName); |
89 | return 1; |
90 | } |
91 | |
92 | /* load dictionary only once */ |
93 | const char* const dictName = argv[argc-1]; |
94 | ZSTD_CDict* const dictPtr = createCDict_orDie(dictName, cLevel); |
95 | |
96 | int u; |
97 | for (u=1; u<argc-1; u++) { |
98 | const char* inFilename = argv[u]; |
99 | char* const outFilename = createOutFilename_orDie(inFilename); |
100 | compress(inFilename, outFilename, dictPtr); |
101 | free(outFilename); |
102 | } |
103 | |
104 | ZSTD_freeCDict(dictPtr); |
105 | printf("All %u files compressed. \n", argc-2); |
106 | return 0; |
107 | } |