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 *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 };
  46
  47 /* Scale: 10 = low, 50 = medium, 100 = high */
  48
  49 #define DEFAULT_COMPRESSION_LEVEL 50
  50
  51 static unsigned int default_compression_levels[ARRAY_LEN(compressor_ops)];
  52
  53 static bool
  54 compressor_ctype_valid(int ctype)
  55 {
  56         return (ctype >= 0 &&
  57                 ctype < ARRAY_LEN(compressor_ops) &&
  58                 compressor_ops[ctype] != NULL);
  59 }
  60
  61 WIMLIBAPI int
  62 wimlib_set_default_compression_level(int ctype, unsigned int compression_level)
  63 {
  64         if (ctype == -1) {
  65                 for (int i = 0; i < ARRAY_LEN(default_compression_levels); i++)
  66                         default_compression_levels[i] = compression_level;
  67         } else {
  68                 if (!compressor_ctype_valid(ctype))
  69                         return WIMLIB_ERR_INVALID_COMPRESSION_TYPE;
  70
  71                 default_compression_levels[ctype] = compression_level;
  72         }
  73         return 0;
  74 }
  75
  76 WIMLIBAPI u64
  77 wimlib_get_compressor_needed_memory(enum wimlib_compression_type ctype,
  78                                     size_t max_block_size,
  79                                     unsigned int compression_level)
  80 {
  81         bool destructive;
  82         const struct compressor_ops *ops;
  83         u64 size;
  84
  85         destructive = (compression_level & WIMLIB_COMPRESSOR_FLAG_DESTRUCTIVE);
  86         compression_level &= ~WIMLIB_COMPRESSOR_FLAG_DESTRUCTIVE;
  87
  88         if (!compressor_ctype_valid(ctype))
  89                 return 0;
  90
  91         if (compression_level > 0xFFFFFF)
  92                 return 0;
  93
  94         if (max_block_size == 0)
  95                 return 0;
  96
  97         ops = compressor_ops[ctype];
  98
  99         if (compression_level == 0)
 100                 compression_level = default_compression_levels[ctype];
 101         if (compression_level == 0)
 102                 compression_level = DEFAULT_COMPRESSION_LEVEL;
 103
 104         if (ops->get_needed_memory) {
 105                 size = ops->get_needed_memory(max_block_size, compression_level,
 106                                               destructive);
 107
 108                 /* 0 is never valid and indicates an invalid max_block_size.  */
 109                 if (size == 0)
 110                         return 0;
 111         } else {
 112                 size = 0;
 113         }
 114         return size + sizeof(struct wimlib_compressor);
 115 }
 116
 117 WIMLIBAPI int
 118 wimlib_create_compressor(enum wimlib_compression_type ctype,
 119                          size_t max_block_size,
 120                          unsigned int compression_level,
 121                          struct wimlib_compressor **c_ret)
 122 {
 123         bool destructive;
 124         struct wimlib_compressor *c;
 125
 126         destructive = (compression_level & WIMLIB_COMPRESSOR_FLAG_DESTRUCTIVE);
 127         compression_level &= ~WIMLIB_COMPRESSOR_FLAG_DESTRUCTIVE;
 128
 129         if (!compressor_ctype_valid(ctype))
 130                 return WIMLIB_ERR_INVALID_COMPRESSION_TYPE;
 131
 132         if (compression_level > 0xFFFFFF)
 133                 return WIMLIB_ERR_INVALID_PARAM;
 134
 135         if (c_ret == NULL)
 136                 return WIMLIB_ERR_INVALID_PARAM;
 137
 138         if (max_block_size == 0)
 139                 return WIMLIB_ERR_INVALID_PARAM;
 140
 141         c = MALLOC(sizeof(*c));
 142         if (c == NULL)
 143                 return WIMLIB_ERR_NOMEM;
 144         c->ops = compressor_ops[ctype];
 145         c->private = NULL;
 146         c->ctype = ctype;
 147         c->max_block_size = max_block_size;
 148         if (c->ops->create_compressor) {
 149                 int ret;
 150
 151                 if (compression_level == 0)
 152                         compression_level = default_compression_levels[ctype];
 153                 if (compression_level == 0)
 154                         compression_level = DEFAULT_COMPRESSION_LEVEL;
 155
 156                 ret = c->ops->create_compressor(max_block_size,
 157                                                 compression_level,
 158                                                 destructive,
 159                                                 &c->private);
 160                 if (ret) {
 161                         FREE(c);
 162                         return ret;
 163                 }
 164         }
 165         *c_ret = c;
 166         return 0;
 167 }
 168
 169 WIMLIBAPI size_t
 170 wimlib_compress(const void *uncompressed_data, size_t uncompressed_size,
 171                 void *compressed_data, size_t compressed_size_avail,
 172                 struct wimlib_compressor *c)
 173 {
 174         if (unlikely(uncompressed_size == 0 || uncompressed_size > c->max_block_size))
 175                 return 0;
 176
 177         return c->ops->compress(uncompressed_data, uncompressed_size,
 178                                 compressed_data, compressed_size_avail,
 179                                 c->private);
 180 }
 181
 182 WIMLIBAPI void
 183 wimlib_free_compressor(struct wimlib_compressor *c)
 184 {
 185         if (c) {
 186                 if (c->ops->free_compressor)
 187                         c->ops->free_compressor(c->private);
 188                 FREE(c);
 189         }
 190 }