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/*
* 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 necessary. 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 noticeable 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
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