1 /**
2 * @file
3 * Zstandard (zstd) compression
4 *
5 * @authors
6 * Copyright (C) 2019-2020 Tino Reichardt <milky-neomutt@mcmilk.de>
7 *
8 * @copyright
9 * This program is free software: you can redistribute it and/or modify it under
10 * the terms of the GNU General Public License as published by the Free Software
11 * Foundation, either version 2 of the License, or (at your option) any later
12 * version.
13 *
14 * This program is distributed in the hope that it will be useful, but WITHOUT
15 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
16 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
17 * details.
18 *
19 * You should have received a copy of the GNU General Public License along with
20 * this program. If not, see <http://www.gnu.org/licenses/>.
21 */
22
23 /**
24 * @page compress_zstd Zstandard (zstd) compression
25 *
26 * Zstandard (zstd) compression.
27 * https://www.zstd.net
28 */
29
30 #include "config.h"
31 #include <stdio.h>
32 #include <zstd.h>
33 #include "private.h"
34 #include "mutt/lib.h"
35 #include "lib.h"
36
37 #define MIN_COMP_LEVEL 1 ///< Minimum compression level for zstd
38 #define MAX_COMP_LEVEL 22 ///< Maximum compression level for zstd
39
40 /**
41 * struct ComprZstdCtx - Private Zstandard Compression Context
42 */
43 struct ComprZstdCtx
44 {
45 void *buf; ///< Temporary buffer
46 short level; ///< Compression Level to be used
47
48 ZSTD_CCtx *cctx; ///< Compression context
49 ZSTD_DCtx *dctx; ///< Decompression context
50 };
51
52 /**
53 * compr_zstd_open - Implements ComprOps::open() - @ingroup compress_open
54 */
compr_zstd_open(short level)55 static void *compr_zstd_open(short level)
56 {
57 struct ComprZstdCtx *ctx = mutt_mem_malloc(sizeof(struct ComprZstdCtx));
58
59 ctx->buf = mutt_mem_malloc(ZSTD_compressBound(1024 * 128));
60 ctx->cctx = ZSTD_createCCtx();
61 ctx->dctx = ZSTD_createDCtx();
62
63 if (!ctx->cctx || !ctx->dctx)
64 {
65 // LCOV_EXCL_START
66 ZSTD_freeCCtx(ctx->cctx);
67 ZSTD_freeDCtx(ctx->dctx);
68 FREE(&ctx->buf);
69 FREE(&ctx);
70 return NULL;
71 // LCOV_EXCL_STOP
72 }
73
74 if ((level < MIN_COMP_LEVEL) || (level > MAX_COMP_LEVEL))
75 {
76 mutt_debug(LL_DEBUG1, "The compression level for %s should be between %d and %d",
77 compr_zstd_ops.name, MIN_COMP_LEVEL, MAX_COMP_LEVEL);
78 level = MIN_COMP_LEVEL;
79 }
80
81 ctx->level = level;
82
83 return ctx;
84 }
85
86 /**
87 * compr_zstd_compress - Implements ComprOps::compress() - @ingroup compress_compress
88 */
compr_zstd_compress(void * cctx,const char * data,size_t dlen,size_t * clen)89 static void *compr_zstd_compress(void *cctx, const char *data, size_t dlen, size_t *clen)
90 {
91 if (!cctx)
92 return NULL;
93
94 struct ComprZstdCtx *ctx = cctx;
95
96 size_t len = ZSTD_compressBound(dlen);
97 mutt_mem_realloc(&ctx->buf, len);
98
99 size_t ret = ZSTD_compressCCtx(ctx->cctx, ctx->buf, len, data, dlen, ctx->level);
100 if (ZSTD_isError(ret))
101 return NULL; // LCOV_EXCL_LINE
102
103 *clen = ret;
104
105 return ctx->buf;
106 }
107
108 /**
109 * compr_zstd_decompress - Implements ComprOps::decompress() - @ingroup compress_decompress
110 */
compr_zstd_decompress(void * cctx,const char * cbuf,size_t clen)111 static void *compr_zstd_decompress(void *cctx, const char *cbuf, size_t clen)
112 {
113 struct ComprZstdCtx *ctx = cctx;
114
115 if (!cctx)
116 return NULL;
117
118 unsigned long long len = ZSTD_getFrameContentSize(cbuf, clen);
119 if (len == ZSTD_CONTENTSIZE_UNKNOWN)
120 return NULL; // LCOV_EXCL_LINE
121 else if (len == ZSTD_CONTENTSIZE_ERROR)
122 return NULL;
123 else if (len == 0)
124 return NULL; // LCOV_EXCL_LINE
125 mutt_mem_realloc(&ctx->buf, len);
126
127 size_t ret = ZSTD_decompressDCtx(ctx->dctx, ctx->buf, len, cbuf, clen);
128 if (ZSTD_isError(ret))
129 return NULL; // LCOV_EXCL_LINE
130
131 return ctx->buf;
132 }
133
134 /**
135 * compr_zstd_close - Implements ComprOps::close() - @ingroup compress_close
136 */
compr_zstd_close(void ** cctx)137 static void compr_zstd_close(void **cctx)
138 {
139 if (!cctx || !*cctx)
140 return;
141
142 struct ComprZstdCtx *ctx = *cctx;
143
144 if (ctx->cctx)
145 ZSTD_freeCCtx(ctx->cctx);
146
147 if (ctx->dctx)
148 ZSTD_freeDCtx(ctx->dctx);
149
150 FREE(&ctx->buf);
151 FREE(cctx);
152 }
153
154 COMPRESS_OPS(zstd, MIN_COMP_LEVEL, MAX_COMP_LEVEL)
155