src/lzfP.h

   1 /*
   2  * Copyright (c) 2000-2007 Marc Alexander Lehmann <schmorp@schmorp.de>
   3  *
   4  * Redistribution and use in source and binary forms, with or without modifica-
   5  * tion, are permitted provided that the following conditions are met:
   6  *
   7  *   1.  Redistributions of source code must retain the above copyright notice,
   8  *       this list of conditions and the following disclaimer.
   9  *
  10  *   2.  Redistributions in binary form must reproduce the above copyright
  11  *       notice, this list of conditions and the following disclaimer in the
  12  *       documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  15  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
  16  * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
  17  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
  18  * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  20  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  21  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
  22  * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  23  * OF THE POSSIBILITY OF SUCH DAMAGE.
  24  *
  25  * Alternatively, the contents of this file may be used under the terms of
  26  * the GNU General Public License ("GPL") version 2 or any later version,
  27  * in which case the provisions of the GPL are applicable instead of
  28  * the above. If you wish to allow the use of your version of this file
  29  * only under the terms of the GPL and not to allow others to use your
  30  * version of this file under the BSD license, indicate your decision
  31  * by deleting the provisions above and replace them with the notice
  32  * and other provisions required by the GPL. If you do not delete the
  33  * provisions above, a recipient may use your version of this file under
  34  * either the BSD or the GPL.
  35  */
  36
  37 #ifndef LZFP_h
  38 #define LZFP_h
  39
  40 #define STANDALONE 1 /* at the moment, this is ok. */
  41
  42 #ifndef STANDALONE
  43 # include "lzf.h"
  44 #endif
  45
  46 /*
  47  * Size of hashtable is (1 << HLOG) * sizeof (char *)
  48  * decompression is independent of the hash table size
  49  * the difference between 15 and 14 is very small
  50  * for small blocks (and 14 is usually a bit faster).
  51  * For a low-memory/faster configuration, use HLOG == 13;
  52  * For best compression, use 15 or 16 (or more, up to 23).
  53  */
  54 #ifndef HLOG
  55 # define HLOG 16
  56 #endif
  57
  58 /*
  59  * Sacrifice very little compression quality in favour of compression speed.
  60  * This gives almost the same compression as the default code, and is
  61  * (very roughly) 15% faster. This is the preferred mode of operation.
  62  */
  63 #ifndef VERY_FAST
  64 # define VERY_FAST 1
  65 #endif
  66
  67 /*
  68  * Sacrifice some more compression quality in favour of compression speed.
  69  * (roughly 1-2% worse compression for large blocks and
  70  * 9-10% for small, redundant, blocks and >>20% better speed in both cases)
  71  * In short: when in need for speed, enable this for binary data,
  72  * possibly disable this for text data.
  73  */
  74 #ifndef ULTRA_FAST
  75 # define ULTRA_FAST 0
  76 #endif
  77
  78 /*
  79  * Unconditionally aligning does not cost very much, so do it if unsure
  80  */
  81 #ifndef STRICT_ALIGN
  82 # define STRICT_ALIGN !(defined(__i386) || defined (__amd64))
  83 #endif
  84
  85 /*
  86  * You may choose to pre-set the hash table (might be faster on some
  87  * modern cpus and large (>>64k) blocks, and also makes compression
  88  * deterministic/repeatable when the configuration otherwise is the same).
  89  */
  90 #ifndef INIT_HTAB
  91 # define INIT_HTAB 0
  92 #endif
  93
  94 /*
  95  * Avoid assigning values to errno variable? for some embedding purposes
  96  * (linux kernel for example), this is neccessary. NOTE: this breaks
  97  * the documentation in lzf.h.
  98  */
  99 #ifndef AVOID_ERRNO
 100 # define AVOID_ERRNO 0
 101 #endif
 102
 103 /*
 104  * Wether to pass the LZF_STATE variable as argument, or allocate it
 105  * on the stack. For small-stack environments, define this to 1.
 106  * NOTE: this breaks the prototype in lzf.h.
 107  */
 108 #ifndef LZF_STATE_ARG
 109 # define LZF_STATE_ARG 0
 110 #endif
 111
 112 /*
 113  * Wether to add extra checks for input validity in lzf_decompress
 114  * and return EINVAL if the input stream has been corrupted. This
 115  * only shields against overflowing the input buffer and will not
 116  * detect most corrupted streams.
 117  * This check is not normally noticable on modern hardware
 118  * (<1% slowdown), but might slow down older cpus considerably.
 119  */
 120 #ifndef CHECK_INPUT
 121 # define CHECK_INPUT 1
 122 #endif
 123
 124 /*****************************************************************************/
 125 /* nothing should be changed below */
 126
 127 typedef unsigned char u8;
 128
 129 typedef const u8 *LZF_STATE[1 << (HLOG)];
 130
 131 #if !STRICT_ALIGN
 132 /* for unaligned accesses we need a 16 bit datatype. */
 133 # include <limits.h>
 134 # if USHRT_MAX == 65535
 135     typedef unsigned short u16;
 136 # elif UINT_MAX == 65535
 137     typedef unsigned int u16;
 138 # else
 139 #  undef STRICT_ALIGN
 140 #  define STRICT_ALIGN 1
 141 # endif
 142 #endif
 143
 144 #if ULTRA_FAST
 145 # if defined(VERY_FAST)
 146 #  undef VERY_FAST
 147 # endif
 148 #endif
 149
 150 #if INIT_HTAB
 151 # ifdef __cplusplus
 152 #  include <cstring>
 153 # else
 154 #  include <string.h>
 155 # endif
 156 #endif
 157
 158 #endif
 159