lzf.h revision 225736
1221828Sgrehan/* 2221828Sgrehan * Copyright (c) 2000-2008 Marc Alexander Lehmann <schmorp@schmorp.de> 3221828Sgrehan * 4221828Sgrehan * Redistribution and use in source and binary forms, with or without modifica- 5221828Sgrehan * tion, are permitted provided that the following conditions are met: 6221828Sgrehan * 7221828Sgrehan * 1. Redistributions of source code must retain the above copyright notice, 8221828Sgrehan * this list of conditions and the following disclaimer. 9221828Sgrehan * 10221828Sgrehan * 2. Redistributions in binary form must reproduce the above copyright 11221828Sgrehan * notice, this list of conditions and the following disclaimer in the 12221828Sgrehan * documentation and/or other materials provided with the distribution. 13221828Sgrehan * 14221828Sgrehan * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 15221828Sgrehan * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER- 16221828Sgrehan * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO 17221828Sgrehan * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE- 18221828Sgrehan * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 19221828Sgrehan * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 20221828Sgrehan * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 21221828Sgrehan * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH- 22221828Sgrehan * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 23221828Sgrehan * OF THE POSSIBILITY OF SUCH DAMAGE. 24221828Sgrehan * 25221828Sgrehan * Alternatively, the contents of this file may be used under the terms of 26221828Sgrehan * the GNU General Public License ("GPL") version 2 or any later version, 27221828Sgrehan * in which case the provisions of the GPL are applicable instead of 28221828Sgrehan * the above. If you wish to allow the use of your version of this file 29221828Sgrehan * only under the terms of the GPL and not to allow others to use your 30221828Sgrehan * version of this file under the BSD license, indicate your decision 31221828Sgrehan * by deleting the provisions above and replace them with the notice 32221828Sgrehan * and other provisions required by the GPL. If you do not delete the 33221828Sgrehan * provisions above, a recipient may use your version of this file under 34221828Sgrehan * either the BSD or the GPL. 35268976Sjhb */ 36221828Sgrehan 37270159Sgrehan#ifndef LZF_H 38270159Sgrehan#define LZF_H 39270159Sgrehan 40221828Sgrehan/*********************************************************************** 41221828Sgrehan** 42221828Sgrehan** lzf -- an extremely fast/free compression/decompression-method 43221828Sgrehan** http://liblzf.plan9.de/ 44221828Sgrehan** 45221828Sgrehan** This algorithm is believed to be patent-free. 46249321Sneel** 47221828Sgrehan***********************************************************************/ 48221828Sgrehan 49221828Sgrehan#define LZF_VERSION 0x0105 /* 1.5, API version */ 50221828Sgrehan 51221828Sgrehan/* 52221828Sgrehan * Compress in_len bytes stored at the memory block starting at 53257396Sneel * in_data and write the result to out_data, up to a maximum length 54221828Sgrehan * of out_len bytes. 55257396Sneel * 56257396Sneel * If the output buffer is not large enough or any error occurs return 0, 57257396Sneel * otherwise return the number of bytes used, which might be considerably 58257396Sneel * more than in_len (but less than 104% of the original size), so it 59257396Sneel * makes sense to always use out_len == in_len - 1), to ensure _some_ 60257396Sneel * compression, and store the data uncompressed otherwise (with a flag, of 61221828Sgrehan * course. 62221828Sgrehan * 63221828Sgrehan * lzf_compress might use different algorithms on different systems and 64221828Sgrehan * even different runs, thus might result in different compressed strings 65249321Sneel * depending on the phase of the moon or similar factors. However, all 66221828Sgrehan * these strings are architecture-independent and will result in the 67221942Sjhb * original data when decompressed using lzf_decompress. 68221942Sjhb * 69221828Sgrehan * The buffers must not be overlapping. 70221828Sgrehan * 71221828Sgrehan * If the option LZF_STATE_ARG is enabled, an extra argument must be 72221828Sgrehan * supplied which is not reflected in this header file. Refer to lzfP.h 73268976Sjhb * and lzf_c.c. 74268976Sjhb * 75221828Sgrehan */ 76249321Sneelunsigned int 77242192Sneellzf_compress (const void *const in_data, unsigned int in_len, 78242192Sneel void *out_data, unsigned int out_len); 79221828Sgrehan 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 */ 95unsigned int 96lzf_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# define STRICT_ALIGN !(defined(__i386) || defined (__amd64)) 136#endif 137 138/* 139 * You may choose to pre-set the hash table (might be faster on some 140 * modern cpus and large (>>64k) blocks, and also makes compression 141 * deterministic/repeatable when the configuration otherwise is the same). 142 */ 143#ifndef INIT_HTAB 144# define INIT_HTAB 1 145#endif 146 147/* 148 * Avoid assigning values to errno variable? for some embedding purposes 149 * (linux kernel for example), this is neccessary. NOTE: this breaks 150 * the documentation in lzf.h. 151 */ 152#ifndef AVOID_ERRNO 153# define AVOID_ERRNO 0 154#endif 155 156/* 157 * Wether to pass the LZF_STATE variable as argument, or allocate it 158 * on the stack. For small-stack environments, define this to 1. 159 * NOTE: this breaks the prototype in lzf.h. 160 */ 161#ifndef LZF_STATE_ARG 162# define LZF_STATE_ARG 0 163#endif 164 165/* 166 * Wether to add extra checks for input validity in lzf_decompress 167 * and return EINVAL if the input stream has been corrupted. This 168 * only shields against overflowing the input buffer and will not 169 * detect most corrupted streams. 170 * This check is not normally noticable on modern hardware 171 * (<1% slowdown), but might slow down older cpus considerably. 172 */ 173#ifndef CHECK_INPUT 174# define CHECK_INPUT 1 175#endif 176 177/*****************************************************************************/ 178/* nothing should be changed below */ 179 180typedef unsigned char u8; 181 182typedef const u8 *LZF_STATE[1 << (HLOG)]; 183 184#if !STRICT_ALIGN 185/* for unaligned accesses we need a 16 bit datatype. */ 186# include <limits.h> 187# if USHRT_MAX == 65535 188 typedef unsigned short u16; 189# elif UINT_MAX == 65535 190 typedef unsigned int u16; 191# else 192# undef STRICT_ALIGN 193# define STRICT_ALIGN 1 194# endif 195#endif 196 197#if ULTRA_FAST 198# if defined(VERY_FAST) 199# undef VERY_FAST 200# endif 201#endif 202 203#if INIT_HTAB 204# ifdef __cplusplus 205# include <cstring> 206# else 207# include <string.h> 208# endif 209#endif 210 211#endif 212