wimlib.net Git - wimlib/blob - src/compress.c

   1 /*
   2  * compress.c
   3  *
   4  * Generic functions for compression, wrapping around actual compression
   5  * implementations.
   6  */
   7
   8 /*
   9  * Copyright (C) 2013, 2014 Eric Biggers
  10  *
  11  * This file is free software; you can redistribute it and/or modify it under
  12  * the terms of the GNU Lesser General Public License as published by the Free
  13  * Software Foundation; either version 3 of the License, or (at your option) any
  14  * later version.
  15  *
  16  * This file is distributed in the hope that it will be useful, but WITHOUT
  17  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  18  * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
  19  * details.
  20  *
  21  * You should have received a copy of the GNU Lesser General Public License
  22  * along with this file; if not, see http://www.gnu.org/licenses/.
  23  */
  24
  25 #ifdef HAVE_CONFIG_H
  26 #  include "config.h"
  27 #endif
  28
  29 #include "wimlib.h"
  30 #include "wimlib/error.h"
  31 #include "wimlib/compressor_ops.h"
  32 #include "wimlib/util.h"
  33
  34 struct wimlib_compressor {
  35         const struct compressor_ops *ops;
  36         void *private;
  37         enum wimlib_compression_type ctype;
  38         size_t max_block_size;
  39 };
  40
  41 static const struct compressor_ops * const compressor_ops[] = {
  42         [WIMLIB_COMPRESSION_TYPE_XPRESS] = &xpress_compressor_ops,
  43         [WIMLIB_COMPRESSION_TYPE_LZX]    = &lzx_compressor_ops,
  44         [WIMLIB_COMPRESSION_TYPE_LZMS]   = &lzms_compressor_ops,
  45 #ifdef WITH_ZSTD
  46         [WIMLIB_COMPRESSION_TYPE_ZSTD]   = &zstd_compressor_ops,
  47 #endif
  48 };
  49
  50 /* Scale: 10 = low, 50 = medium, 100 = high */
  51
  52 #define DEFAULT_COMPRESSION_LEVEL 50
  53
  54 static unsigned int default_compression_levels[ARRAY_LEN(compressor_ops)];
  55
  56 static bool
  57 compressor_ctype_valid(int ctype)
  58 {
  59         return (ctype >= 0 &&
  60                 ctype < ARRAY_LEN(compressor_ops) &&
  61                 compressor_ops[ctype] != NULL);
  62 }
  63
  64 WIMLIBAPI int
  65 wimlib_set_default_compression_level(int ctype, unsigned int compression_level)
  66 {
  67         if (ctype == -1) {
  68                 for (int i = 0; i < ARRAY_LEN(default_compression_levels); i++)
  69                         default_compression_levels[i] = compression_level;
  70         } else {
  71                 if (!compressor_ctype_valid(ctype))
  72                         return WIMLIB_ERR_INVALID_COMPRESSION_TYPE;
  73
  74                 default_compression_levels[ctype] = compression_level;
  75         }
  76         return 0;
  77 }
  78
  79 WIMLIBAPI u64
  80 wimlib_get_compressor_needed_memory(enum wimlib_compression_type ctype,
  81                                     size_t max_block_size,
  82                                     unsigned int compression_level)
  83 {
  84         bool destructive;
  85         const struct compressor_ops *ops;
  86         u64 size;
  87
  88         destructive = (compression_level & WIMLIB_COMPRESSOR_FLAG_DESTRUCTIVE);
  89         compression_level &= ~WIMLIB_COMPRESSOR_FLAG_DESTRUCTIVE;
  90
  91         if (!compressor_ctype_valid(ctype))
  92                 return 0;
  93
  94         if (compression_level > 0xFFFFFF)
  95                 return 0;
  96
  97         if (max_block_size == 0)
  98                 return 0;
  99
 100         ops = compressor_ops[ctype];
 101
 102         if (compression_level == 0)
 103                 compression_level = default_compression_levels[ctype];
 104         if (compression_level == 0)
 105                 compression_level = DEFAULT_COMPRESSION_LEVEL;
 106
 107         if (ops->get_needed_memory) {
 108                 size = ops->get_needed_memory(max_block_size, compression_level,
 109                                               destructive);
 110
 111                 /* 0 is never valid and indicates an invalid max_block_size.  */
 112                 if (size == 0)
 113                         return 0;
 114         } else {
 115                 size = 0;
 116         }
 117         return size + sizeof(struct wimlib_compressor);
 118 }
 119
 120 WIMLIBAPI int
 121 wimlib_create_compressor(enum wimlib_compression_type ctype,
 122                          size_t max_block_size,
 123                          unsigned int compression_level,
 124                          struct wimlib_compressor **c_ret)
 125 {
 126         bool destructive;
 127         struct wimlib_compressor *c;
 128
 129         destructive = (compression_level & WIMLIB_COMPRESSOR_FLAG_DESTRUCTIVE);
 130         compression_level &= ~WIMLIB_COMPRESSOR_FLAG_DESTRUCTIVE;
 131
 132         if (!compressor_ctype_valid(ctype))
 133                 return WIMLIB_ERR_INVALID_COMPRESSION_TYPE;
 134
 135         if (compression_level > 0xFFFFFF)
 136                 return WIMLIB_ERR_INVALID_PARAM;
 137
 138         if (c_ret == NULL)
 139                 return WIMLIB_ERR_INVALID_PARAM;
 140
 141         if (max_block_size == 0)
 142                 return WIMLIB_ERR_INVALID_PARAM;
 143
 144         c = MALLOC(sizeof(*c));
 145         if (c == NULL)
 146                 return WIMLIB_ERR_NOMEM;
 147         c->ops = compressor_ops[ctype];
 148         c->private = NULL;
 149         c->ctype = ctype;
 150         c->max_block_size = max_block_size;
 151         if (c->ops->create_compressor) {
 152                 int ret;
 153
 154                 if (compression_level == 0)
 155                         compression_level = default_compression_levels[ctype];
 156                 if (compression_level == 0)
 157                         compression_level = DEFAULT_COMPRESSION_LEVEL;
 158
 159                 ret = c->ops->create_compressor(max_block_size,
 160                                                 compression_level,
 161                                                 destructive,
 162                                                 &c->private);
 163                 if (ret) {
 164                         FREE(c);
 165                         return ret;
 166                 }
 167         }
 168         *c_ret = c;
 169         return 0;
 170 }
 171
 172 WIMLIBAPI size_t
 173 wimlib_compress(const void *uncompressed_data, size_t uncompressed_size,
 174                 void *compressed_data, size_t compressed_size_avail,
 175                 struct wimlib_compressor *c)
 176 {
 177         if (unlikely(uncompressed_size == 0 || uncompressed_size > c->max_block_size))
 178                 return 0;
 179
 180         return c->ops->compress(uncompressed_data, uncompressed_size,
 181                                 compressed_data, compressed_size_avail,
 182                                 c->private);
 183 }
 184
 185 WIMLIBAPI void
 186 wimlib_free_compressor(struct wimlib_compressor *c)
 187 {
 188         if (c) {
 189                 if (c->ops->free_compressor)
 190                         c->ops->free_compressor(c->private);
 191                 FREE(c);
 192         }
 193 }