xref: /freebsd/sys/contrib/zstd/examples/dictionary_compression.c (revision 8ddb146abcdf061be9f2c0db7e391697dafad85c)
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 #include <stdio.h>     // printf
11 #include <stdlib.h>    // free
12 #include <string.h>    // memset, strcat
13 #include <zstd.h>      // presumes zstd library is installed
14 #include "common.h"    // Helper functions, CHECK(), and CHECK_ZSTD()
15 
16 /* createDict() :
17    `dictFileName` is supposed to have been created using `zstd --train` */
18 static ZSTD_CDict* createCDict_orDie(const char* dictFileName, int cLevel)
19 {
20     size_t dictSize;
21     printf("loading dictionary %s \n", dictFileName);
22     void* const dictBuffer = mallocAndLoadFile_orDie(dictFileName, &dictSize);
23     ZSTD_CDict* const cdict = ZSTD_createCDict(dictBuffer, dictSize, cLevel);
24     CHECK(cdict != NULL, "ZSTD_createCDict() failed!");
25     free(dictBuffer);
26     return cdict;
27 }
28 
29 
30 static void compress(const char* fname, const char* oname, const ZSTD_CDict* cdict)
31 {
32     size_t fSize;
33     void* const fBuff = mallocAndLoadFile_orDie(fname, &fSize);
34     size_t const cBuffSize = ZSTD_compressBound(fSize);
35     void* const cBuff = malloc_orDie(cBuffSize);
36 
37     /* Compress using the dictionary.
38      * This function writes the dictionary id, and content size into the header.
39      * But, it doesn't use a checksum. You can control these options using the
40      * advanced API: ZSTD_CCtx_setParameter(), ZSTD_CCtx_refCDict(),
41      * and ZSTD_compress2().
42      */
43     ZSTD_CCtx* const cctx = ZSTD_createCCtx();
44     CHECK(cctx != NULL, "ZSTD_createCCtx() failed!");
45     size_t const cSize = ZSTD_compress_usingCDict(cctx, cBuff, cBuffSize, fBuff, fSize, cdict);
46     CHECK_ZSTD(cSize);
47 
48     saveFile_orDie(oname, cBuff, cSize);
49 
50     /* success */
51     printf("%25s : %6u -> %7u - %s \n", fname, (unsigned)fSize, (unsigned)cSize, oname);
52 
53     ZSTD_freeCCtx(cctx);   /* never fails */
54     free(fBuff);
55     free(cBuff);
56 }
57 
58 
59 static char* createOutFilename_orDie(const char* filename)
60 {
61     size_t const inL = strlen(filename);
62     size_t const outL = inL + 5;
63     void* outSpace = malloc_orDie(outL);
64     memset(outSpace, 0, outL);
65     strcat(outSpace, filename);
66     strcat(outSpace, ".zst");
67     return (char*)outSpace;
68 }
69 
70 int main(int argc, const char** argv)
71 {
72     const char* const exeName = argv[0];
73     int const cLevel = 3;
74 
75     if (argc<3) {
76         fprintf(stderr, "wrong arguments\n");
77         fprintf(stderr, "usage:\n");
78         fprintf(stderr, "%s [FILES] dictionary\n", exeName);
79         return 1;
80     }
81 
82     /* load dictionary only once */
83     const char* const dictName = argv[argc-1];
84     ZSTD_CDict* const dictPtr = createCDict_orDie(dictName, cLevel);
85 
86     int u;
87     for (u=1; u<argc-1; u++) {
88         const char* inFilename = argv[u];
89         char* const outFilename = createOutFilename_orDie(inFilename);
90         compress(inFilename, outFilename, dictPtr);
91         free(outFilename);
92     }
93 
94     ZSTD_freeCDict(dictPtr);
95     printf("All %u files compressed. \n", argc-2);
96     return 0;
97 }
98