1 /* 2 * Copyright (c) 2000-2008 Marc Alexander Lehmann <schmorp@schmorp.de> 3 * 4 * Redistribution and use in source and binary forms, with or without modifica- 5 * tion, are permitted provided that the following conditions are met: 6 * 7 * 1. Redistributions of source code must retain the above copyright notice, 8 * this list of conditions and the following disclaimer. 9 * 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 15 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER- 16 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO 17 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE- 18 * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 20 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 21 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH- 22 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 23 * OF THE POSSIBILITY OF SUCH DAMAGE. 24 * 25 * Alternatively, the contents of this file may be used under the terms of 26 * the GNU General Public License ("GPL") version 2 or any later version, 27 * in which case the provisions of the GPL are applicable instead of 28 * the above. If you wish to allow the use of your version of this file 29 * only under the terms of the GPL and not to allow others to use your 30 * version of this file under the BSD license, indicate your decision 31 * by deleting the provisions above and replace them with the notice 32 * and other provisions required by the GPL. If you do not delete the 33 * provisions above, a recipient may use your version of this file under 34 * either the BSD or the GPL. 35 */ 36 37 #ifndef LZF_H 38 #define LZF_H 39 40 /*********************************************************************** 41 ** 42 ** lzf -- an extremely fast/free compression/decompression-method 43 ** http://liblzf.plan9.de/ 44 ** 45 ** This algorithm is believed to be patent-free. 46 ** 47 ***********************************************************************/ 48 49 #define LZF_VERSION 0x0105 /* 1.5, API version */ 50 51 /* 52 * Compress in_len bytes stored at the memory block starting at 53 * in_data and write the result to out_data, up to a maximum length 54 * of out_len bytes. 55 * 56 * If the output buffer is not large enough or any error occurs return 0, 57 * otherwise return the number of bytes used, which might be considerably 58 * more than in_len (but less than 104% of the original size), so it 59 * makes sense to always use out_len == in_len - 1), to ensure _some_ 60 * compression, and store the data uncompressed otherwise (with a flag, of 61 * course. 62 * 63 * lzf_compress might use different algorithms on different systems and 64 * even different runs, thus might result in different compressed strings 65 * depending on the phase of the moon or similar factors. However, all 66 * these strings are architecture-independent and will result in the 67 * original data when decompressed using lzf_decompress. 68 * 69 * The buffers must not be overlapping. 70 * 71 * If the option LZF_STATE_ARG is enabled, an extra argument must be 72 * supplied which is not reflected in this header file. Refer to lzfP.h 73 * and lzf_c.c. 74 * 75 */ 76 unsigned int 77 lzf_compress (const void *const in_data, unsigned int in_len, 78 void *out_data, unsigned int out_len); 79 80 /* 81 * Decompress data compressed with some version of the lzf_compress 82 * function and stored at location in_data and length in_len. The result 83 * will be stored at out_data up to a maximum of out_len characters. 84 * 85 * If the output buffer is not large enough to hold the decompressed 86 * data, a 0 is returned and errno is set to E2BIG. Otherwise the number 87 * of decompressed bytes (i.e. the original length of the data) is 88 * returned. 89 * 90 * If an error in the compressed data is detected, a zero is returned and 91 * errno is set to EINVAL. 92 * 93 * This function is very fast, about as fast as a copying loop. 94 */ 95 unsigned int 96 lzf_decompress (const void *const in_data, unsigned int in_len, 97 void *out_data, unsigned int out_len); 98 99 /* 100 * Size of hashtable is (1 << HLOG) * sizeof (char *) 101 * decompression is independent of the hash table size 102 * the difference between 15 and 14 is very small 103 * for small blocks (and 14 is usually a bit faster). 104 * For a low-memory/faster configuration, use HLOG == 13; 105 * For best compression, use 15 or 16 (or more, up to 23). 106 */ 107 #ifndef HLOG 108 # define HLOG 16 109 #endif 110 111 /* 112 * Sacrifice very little compression quality in favour of compression speed. 113 * This gives almost the same compression as the default code, and is 114 * (very roughly) 15% faster. This is the preferred mode of operation. 115 */ 116 #ifndef VERY_FAST 117 # define VERY_FAST 1 118 #endif 119 120 /* 121 * Sacrifice some more compression quality in favour of compression speed. 122 * (roughly 1-2% worse compression for large blocks and 123 * 9-10% for small, redundant, blocks and >>20% better speed in both cases) 124 * In short: when in need for speed, enable this for binary data, 125 * possibly disable this for text data. 126 */ 127 #ifndef ULTRA_FAST 128 # define ULTRA_FAST 0 129 #endif 130 131 /* 132 * Unconditionally aligning does not cost very much, so do it if unsure 133 */ 134 #ifndef STRICT_ALIGN 135 # if !(defined(__i386) || defined (__amd64)) 136 # define STRICT_ALIGN 1 137 # else 138 # define STRICT_ALIGN 0 139 # endif 140 #endif 141 142 /* 143 * You may choose to pre-set the hash table (might be faster on some 144 * modern cpus and large (>>64k) blocks, and also makes compression 145 * deterministic/repeatable when the configuration otherwise is the same). 146 */ 147 #ifndef INIT_HTAB 148 # define INIT_HTAB 1 149 #endif 150 151 /* 152 * Avoid assigning values to errno variable? for some embedding purposes 153 * (linux kernel for example), this is necessary. NOTE: this breaks 154 * the documentation in lzf.h. 155 */ 156 #ifndef AVOID_ERRNO 157 # define AVOID_ERRNO 0 158 #endif 159 160 /* 161 * Wether to pass the LZF_STATE variable as argument, or allocate it 162 * on the stack. For small-stack environments, define this to 1. 163 * NOTE: this breaks the prototype in lzf.h. 164 */ 165 #ifndef LZF_STATE_ARG 166 # define LZF_STATE_ARG 0 167 #endif 168 169 /* 170 * Wether to add extra checks for input validity in lzf_decompress 171 * and return EINVAL if the input stream has been corrupted. This 172 * only shields against overflowing the input buffer and will not 173 * detect most corrupted streams. 174 * This check is not normally noticeable on modern hardware 175 * (<1% slowdown), but might slow down older cpus considerably. 176 */ 177 #ifndef CHECK_INPUT 178 # define CHECK_INPUT 1 179 #endif 180 181 /*****************************************************************************/ 182 /* nothing should be changed below */ 183 184 typedef unsigned char u8; 185 186 typedef const u8 *LZF_STATE[1 << (HLOG)]; 187 188 #if !STRICT_ALIGN 189 /* for unaligned accesses we need a 16 bit datatype. */ 190 # include <limits.h> 191 # if USHRT_MAX == 65535 192 typedef unsigned short u16; 193 # elif UINT_MAX == 65535 194 typedef unsigned int u16; 195 # else 196 # undef STRICT_ALIGN 197 # define STRICT_ALIGN 1 198 # endif 199 #endif 200 201 #if ULTRA_FAST 202 # if defined(VERY_FAST) 203 # undef VERY_FAST 204 # endif 205 #endif 206 207 #if INIT_HTAB 208 # ifdef __cplusplus 209 # include <cstring> 210 # else 211 # include <string.h> 212 # endif 213 #endif 214 215 #endif 216