8cd3d45ad9
- HOLE - it simply turns all-zero blocks into few bytes header; it is extremely fast, so it is turned on by default; it is mostly intended to speed up initial synchronization where we expect many zeros; - LZF - very fast algorithm by Marc Alexander Lehmann, which shows very decent compression ratio and has BSD license. MFC after: 2 weeks
212 lines
7.2 KiB
C
212 lines
7.2 KiB
C
/*
|
|
* Copyright (c) 2000-2008 Marc Alexander Lehmann <schmorp@schmorp.de>
|
|
*
|
|
* 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
|
|
|
|
/***********************************************************************
|
|
**
|
|
** lzf -- an extremely fast/free compression/decompression-method
|
|
** http://liblzf.plan9.de/
|
|
**
|
|
** This algorithm is believed to be patent-free.
|
|
**
|
|
***********************************************************************/
|
|
|
|
#define LZF_VERSION 0x0105 /* 1.5, API version */
|
|
|
|
/*
|
|
* Compress in_len bytes stored at the memory block starting at
|
|
* in_data and write the result to out_data, up to a maximum length
|
|
* of out_len bytes.
|
|
*
|
|
* If the output buffer is not large enough or any error occurs return 0,
|
|
* otherwise return the number of bytes used, which might be considerably
|
|
* more than in_len (but less than 104% of the original size), so it
|
|
* makes sense to always use out_len == in_len - 1), to ensure _some_
|
|
* compression, and store the data uncompressed otherwise (with a flag, of
|
|
* course.
|
|
*
|
|
* lzf_compress might use different algorithms on different systems and
|
|
* even different runs, thus might result in different compressed strings
|
|
* depending on the phase of the moon or similar factors. However, all
|
|
* these strings are architecture-independent and will result in the
|
|
* original data when decompressed using lzf_decompress.
|
|
*
|
|
* The buffers must not be overlapping.
|
|
*
|
|
* If the option LZF_STATE_ARG is enabled, an extra argument must be
|
|
* supplied which is not reflected in this header file. Refer to lzfP.h
|
|
* and lzf_c.c.
|
|
*
|
|
*/
|
|
unsigned int
|
|
lzf_compress (const void *const in_data, unsigned int in_len,
|
|
void *out_data, unsigned int out_len);
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
unsigned int
|
|
lzf_decompress (const void *const in_data, unsigned int in_len,
|
|
void *out_data, unsigned int out_len);
|
|
|
|
/*
|
|
* Size of hashtable is (1 << HLOG) * sizeof (char *)
|
|
* decompression is independent of the hash table size
|
|
* the difference between 15 and 14 is very small
|
|
* for small blocks (and 14 is usually a bit faster).
|
|
* For a low-memory/faster configuration, use HLOG == 13;
|
|
* For best compression, use 15 or 16 (or more, up to 23).
|
|
*/
|
|
#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 1
|
|
#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 <limits.h>
|
|
# 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 <cstring>
|
|
# else
|
|
# include <string.h>
|
|
# endif
|
|
#endif
|
|
|
|
#endif
|