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 
12 #include <stdio.h>     // printf
13 #include <stdlib.h>    // free
14 #include <string.h>    // memset, strcat, strlen
15 #include <zstd.h>      // presumes zstd library is installed
16 #include "common.h"    // Helper functions, CHECK(), and CHECK_ZSTD()
17 
18 
19 static void compressFile_orDie(const char* fname, const char* outName, int cLevel)
20 {
21     /* Open the input and output files. */
22     FILE* const fin  = fopen_orDie(fname, "rb");
23     FILE* const fout = fopen_orDie(outName, "wb");
24     /* Create the input and output buffers.
25      * They may be any size, but we recommend using these functions to size them.
26      * Performance will only suffer significantly for very tiny buffers.
27      */
28     size_t const buffInSize = ZSTD_CStreamInSize();
29     void*  const buffIn  = malloc_orDie(buffInSize);
30     size_t const buffOutSize = ZSTD_CStreamOutSize();
31     void*  const buffOut = malloc_orDie(buffOutSize);
32 
33     /* Create the context. */
34     ZSTD_CCtx* const cctx = ZSTD_createCCtx();
35     CHECK(cctx != NULL, "ZSTD_createCCtx() failed!");
36 
37     /* Set any parameters you want.
38      * Here we set the compression level, and enable the checksum.
39      */
40     CHECK_ZSTD( ZSTD_CCtx_setParameter(cctx, ZSTD_c_compressionLevel, cLevel) );
41     CHECK_ZSTD( ZSTD_CCtx_setParameter(cctx, ZSTD_c_checksumFlag, 1) );
42     ZSTD_CCtx_setParameter(cctx, ZSTD_c_nbWorkers, 4);
43 
44     /* This loop read from the input file, compresses that entire chunk,
45      * and writes all output produced to the output file.
46      */
47     size_t const toRead = buffInSize;
48     for (;;) {
49         size_t read = fread_orDie(buffIn, toRead, fin);
50         /* Select the flush mode.
51          * If the read may not be finished (read == toRead) we use
52          * ZSTD_e_continue. If this is the last chunk, we use ZSTD_e_end.
53          * Zstd optimizes the case where the first flush mode is ZSTD_e_end,
54          * since it knows it is compressing the entire source in one pass.
55          */
56         int const lastChunk = (read < toRead);
57         ZSTD_EndDirective const mode = lastChunk ? ZSTD_e_end : ZSTD_e_continue;
58         /* Set the input buffer to what we just read.
59          * We compress until the input buffer is empty, each time flushing the
60          * output.
61          */
62         ZSTD_inBuffer input = { buffIn, read, 0 };
63         int finished;
64         do {
65             /* Compress into the output buffer and write all of the output to
66              * the file so we can reuse the buffer next iteration.
67              */
68             ZSTD_outBuffer output = { buffOut, buffOutSize, 0 };
69             size_t const remaining = ZSTD_compressStream2(cctx, &output , &input, mode);
70             CHECK_ZSTD(remaining);
71             fwrite_orDie(buffOut, output.pos, fout);
72             /* If we're on the last chunk we're finished when zstd returns 0,
73              * which means its consumed all the input AND finished the frame.
74              * Otherwise, we're finished when we've consumed all the input.
75              */
76             finished = lastChunk ? (remaining == 0) : (input.pos == input.size);
77         } while (!finished);
78         CHECK(input.pos == input.size,
79               "Impossible: zstd only returns 0 when the input is completely consumed!");
80 
81         if (lastChunk) {
82             break;
83         }
84     }
85 
86     ZSTD_freeCCtx(cctx);
87     fclose_orDie(fout);
88     fclose_orDie(fin);
89     free(buffIn);
90     free(buffOut);
91 }
92 
93 
94 static char* createOutFilename_orDie(const char* filename)
95 {
96     size_t const inL = strlen(filename);
97     size_t const outL = inL + 5;
98     void* const outSpace = malloc_orDie(outL);
99     memset(outSpace, 0, outL);
100     strcat(outSpace, filename);
101     strcat(outSpace, ".zst");
102     return (char*)outSpace;
103 }
104 
105 int main(int argc, const char** argv)
106 {
107     const char* const exeName = argv[0];
108 
109     if (argc!=2) {
110         printf("wrong arguments\n");
111         printf("usage:\n");
112         printf("%s FILE\n", exeName);
113         return 1;
114     }
115 
116     const char* const inFilename = argv[1];
117 
118     char* const outFilename = createOutFilename_orDie(inFilename);
119     compressFile_orDie(inFilename, outFilename, 1);
120 
121     free(outFilename);   /* not strictly required, since program execution stops there,
122                           * but some static analyzer main complain otherwise */
123     return 0;
124 }
125