/* * Copyright (c) 2000-2008 Marc Alexander Lehmann * * Redistribution and use in source and binary forms, with or without modifica- * tion, are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER- * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE- * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH- * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED * OF THE POSSIBILITY OF SUCH DAMAGE. * * Alternatively, the contents of this file may be used under the terms of * the GNU General Public License ("GPL") version 2 or any later version, * in which case the provisions of the GPL are applicable instead of * the above. If you wish to allow the use of your version of this file * only under the terms of the GPL and not to allow others to use your * version of this file under the BSD license, indicate your decision * by deleting the provisions above and replace them with the notice * and other provisions required by the GPL. If you do not delete the * provisions above, a recipient may use your version of this file under * either the BSD or the GPL. */ #ifndef __LZF_H #define __LZF_H #define LZF_MARGIN 128 #define LZF_VERSION 0x0105 /* 1.5, API version */ #define AVOID_ERRNO 1 #ifndef HLOG # define HLOG 16 #endif /* * Sacrifice very little compression quality in favour of compression speed. * This gives almost the same compression as the default code, and is * (very roughly) 15% faster. This is the preferred mode of operation. */ #ifndef VERY_FAST # define VERY_FAST 1 #endif /* * Sacrifice some more compression quality in favour of compression speed. * (roughly 1-2% worse compression for large blocks and * 9-10% for small, redundant, blocks and >>20% better speed in both cases) * In short: when in need for speed, enable this for binary data, * possibly disable this for text data. */ #ifndef ULTRA_FAST # define ULTRA_FAST 0 #endif /* * Unconditionally aligning does not cost very much, so do it if unsure */ #ifndef STRICT_ALIGN # define STRICT_ALIGN !(defined(__i386) || defined (__amd64)) #endif /* * You may choose to pre-set the hash table (might be faster on some * modern cpus and large (>>64k) blocks, and also makes compression * deterministic/repeatable when the configuration otherwise is the same). */ #ifndef INIT_HTAB # define INIT_HTAB 0 #endif /* * Avoid assigning values to errno variable? for some embedding purposes * (linux kernel for example), this is neccessary. NOTE: this breaks * the documentation in lzf.h. */ #ifndef AVOID_ERRNO # define AVOID_ERRNO 0 #endif /* * Wether to pass the LZF_STATE variable as argument, or allocate it * on the stack. For small-stack environments, define this to 1. * NOTE: this breaks the prototype in lzf.h. */ #ifndef LZF_STATE_ARG # define LZF_STATE_ARG 0 #endif /* * Wether to add extra checks for input validity in lzf_decompress * and return EINVAL if the input stream has been corrupted. This * only shields against overflowing the input buffer and will not * detect most corrupted streams. * This check is not normally noticable on modern hardware * (<1% slowdown), but might slow down older cpus considerably. */ #ifndef CHECK_INPUT # define CHECK_INPUT 1 #endif /*****************************************************************************/ /* nothing should be changed below */ typedef unsigned char u8; typedef const u8 *LZF_STATE[1 << (HLOG)]; #if !STRICT_ALIGN /* for unaligned accesses we need a 16 bit datatype. */ # include # if USHRT_MAX == 65535 typedef unsigned short u16; # elif UINT_MAX == 65535 typedef unsigned int u16; # else # undef STRICT_ALIGN # define STRICT_ALIGN 1 # endif #endif #if ULTRA_FAST # if defined(VERY_FAST) # undef VERY_FAST # endif #endif #if INIT_HTAB # ifdef __cplusplus # include # else # include # endif #endif #define HSIZE (1 << (HLOG)) /* * don't play with this unless you benchmark! * decompression is not dependent on the hash function * the hashing function might seem strange, just believe me * it works ;) */ #ifndef FRST # define FRST(p) (((p[0]) << 8) | p[1]) # define NEXT(v,p) (((v) << 8) | p[2]) # if ULTRA_FAST # define IDX(h) ((( h >> (3*8 - HLOG)) - h ) & (HSIZE - 1)) # elif VERY_FAST # define IDX(h) ((( h >> (3*8 - HLOG)) - h*5) & (HSIZE - 1)) # else # define IDX(h) ((((h ^ (h << 5)) >> (3*8 - HLOG)) - h*5) & (HSIZE - 1)) # endif #endif /* * IDX works because it is very similar to a multiplicative hash, e.g. * ((h * 57321 >> (3*8 - HLOG)) & (HSIZE - 1)) * the latter is also quite fast on newer CPUs, and compresses similarly. * * the next one is also quite good, albeit slow ;) * (int)(cos(h & 0xffffff) * 1e6) */ #if 0 /* original lzv-like hash function, much worse and thus slower */ # define FRST(p) (p[0] << 5) ^ p[1] # define NEXT(v,p) ((v) << 5) ^ p[2] # define IDX(h) ((h) & (HSIZE - 1)) #endif #define MAX_LIT (1 << 5) #define MAX_OFF (1 << 13) #define MAX_REF ((1 << 8) + (1 << 3)) #if __GNUC__ >= 3 # define expect(expr,value) __builtin_expect ((expr),(value)) #else # define expect(expr,value) (expr) #endif #define expect_false(expr) expect ((expr) != 0, 0) #define expect_true(expr) expect ((expr) != 0, 1) /* * compressed format * * 000LLLLL ; literal * LLLooooo oooooooo ; backref L * 111ooooo LLLLLLLL oooooooo ; backref L+7 * */ unsigned int lzf_compress (const void *const in_data, unsigned int in_len, void *out_data, unsigned int out_len #if LZF_STATE_ARG , LZF_STATE htab #endif ); /* * Decompress data compressed with some version of the lzf_compress * function and stored at location in_data and length in_len. The result * will be stored at out_data up to a maximum of out_len characters. * * If the output buffer is not large enough to hold the decompressed * data, a 0 is returned and errno is set to E2BIG. Otherwise the number * of decompressed bytes (i.e. the original length of the data) is * returned. * * If an error in the compressed data is detected, a zero is returned and * errno is set to EINVAL. * * This function is very fast, about as fast as a copying loop. */ #if AVOID_ERRNO # define SET_ERRNO(n) #else # include # define SET_ERRNO(n) errno = (n) #endif #if (__i386 || __amd64) && __GNUC__ >= 3 # define lzf_movsb(dst, src, len) \ asm ("rep movsb" \ : "=D" (dst), "=S" (src), "=c" (len) \ : "0" (dst), "1" (src), "2" (len)); #endif unsigned int lzf_decompress (const void *const in_data, unsigned int in_len, void *out_data, unsigned int out_len); #endif