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View File Name : lzfP.h

/*
 * Copyright (c) 2000-2007 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 LZFP_h
#define LZFP_h

#define STANDALONE 1 /* at the moment, this is ok. */

#ifndef STANDALONE
# include "lzf.h"
#endif

/*
 * 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 22).
 */
#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. Avoiding errno has no speed impact.
 */
#ifndef AVOID_ERRNO
# define AVOID_ERRNO 0
#endif

/*
 * Whether 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

/*
 * Whether 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

/*
 * Whether the target CPU has a slow multiplication. This affects
 * the default hash function for the compressor, and enables a slightly
 * worse hash function that needs only shifts.
 */
#ifndef MULTIPLICATION_IS_SLOW
# define MULTIPLICATION_IS_SLOW 0
#endif

/*
 * If defined, then this data type will be used for storing offsets.
 * This can be useful if you want to use a huge hashtable, want to
 * conserve memory, or both, and your data fits into e.g. 64kb.
 * If instead you want to compress data > 4GB, then it's better to
 * to "#define LZF_USE_OFFSETS 0" instead.
 */
/*#define LZF_HSLOT unsigned short*/

/*
 * Whether to store pointers or offsets inside the hash table. On
 * 64 bit architetcures, pointers take up twice as much space,
 * and might also be slower. Default is to autodetect.
 */
/*#define LZF_USE_OFFSETS autodetect */

/*
 * Whether to optimise code for size, at the expense of speed. Use
 * this when you are extremely tight on memory, perhaps in combination
 * with AVOID_ERRNO 1 and CHECK_INPUT 0.
 */
#ifndef OPTIMISE_SIZE
# ifdef __OPTIMIZE_SIZE__
#  define OPTIMISE_SIZE 1
# else
#  define OPTIMISE_SIZE 0
# endif
#endif

/*****************************************************************************/
/* nothing should be changed below */

#ifdef __cplusplus
# include <cstring>
# include <climits>
using namespace std;
#else
# include <string.h>
# include <limits.h>
#endif

#if ULTRA_FAST
# undef VERY_FAST
#endif

#ifndef LZF_USE_OFFSETS
# ifdef _WIN32
#  define LZF_USE_OFFSETS defined(_M_X64)
# else
#  if __cplusplus > 199711L
#   include <cstdint>
#  else
#   include <stdint.h>
#  endif
#  define LZF_USE_OFFSETS (UINTPTR_MAX > 0xffffffffU)
# endif
#endif

typedef unsigned char u8;

#ifdef LZF_HSLOT
# define LZF_HSLOT_BIAS ((const u8 *)in_data)
#else
# if LZF_USE_OFFSETS
#  define LZF_HSLOT_BIAS ((const u8 *)in_data)
   typedef unsigned int LZF_HSLOT;
# else
#  define LZF_HSLOT_BIAS 0
   typedef const u8 *LZF_HSLOT;
# endif
#endif

#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

#define LZF_MAX_LIT (1 <<  5)
#define LZF_MAX_OFF (1 << 13)
#define LZF_MAX_REF ((1 << 8) + (1 << 3))

typedef LZF_HSLOT LZF_STATE[1 << (HLOG)];

typedef struct
{
  const u8 *first [1 << (6+8)]; /* most recent occurance of a match */
  u16 prev [LZF_MAX_OFF]; /* how many bytes to go backwards for the next match */
} LZF_STATE_BEST[1];

#endif