lzo/src/lzo_util.c

   1 /* lzo_util.c -- utilities for the LZO library
   2
   3    This file is part of the LZO real-time data compression library.
   4
   5    Copyright (C) 2008 Markus Franz Xaver Johannes Oberhumer
   6    Copyright (C) 2007 Markus Franz Xaver Johannes Oberhumer
   7    Copyright (C) 2006 Markus Franz Xaver Johannes Oberhumer
   8    Copyright (C) 2005 Markus Franz Xaver Johannes Oberhumer
   9    Copyright (C) 2004 Markus Franz Xaver Johannes Oberhumer
  10    Copyright (C) 2003 Markus Franz Xaver Johannes Oberhumer
  11    Copyright (C) 2002 Markus Franz Xaver Johannes Oberhumer
  12    Copyright (C) 2001 Markus Franz Xaver Johannes Oberhumer
  13    Copyright (C) 2000 Markus Franz Xaver Johannes Oberhumer
  14    Copyright (C) 1999 Markus Franz Xaver Johannes Oberhumer
  15    Copyright (C) 1998 Markus Franz Xaver Johannes Oberhumer
  16    Copyright (C) 1997 Markus Franz Xaver Johannes Oberhumer
  17    Copyright (C) 1996 Markus Franz Xaver Johannes Oberhumer
  18    All Rights Reserved.
  19
  20    The LZO library is free software; you can redistribute it and/or
  21    modify it under the terms of the GNU General Public License as
  22    published by the Free Software Foundation; either version 2 of
  23    the License, or (at your option) any later version.
  24
  25    The LZO library is distributed in the hope that it will be useful,
  26    but WITHOUT ANY WARRANTY; without even the implied warranty of
  27    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  28    GNU General Public License for more details.
  29
  30    You should have received a copy of the GNU General Public License
  31    along with the LZO library; see the file COPYING.
  32    If not, write to the Free Software Foundation, Inc.,
  33    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  34
  35    Markus F.X.J. Oberhumer
  36    <markus@oberhumer.com>
  37    http://www.oberhumer.com/opensource/lzo/
  38  */
  39
  40
  41 #include "lzo_conf.h"
  42
  43
  44 /***********************************************************************
  45 //
  46 ************************************************************************/
  47
  48 /* If you use the LZO library in a product, I would appreciate that you
  49  * keep this copyright string in the executable of your product.
  50 .*/
  51
  52 const char __lzo_copyright[] =
  53 #if !defined(__LZO_IN_MINLZO)
  54     /* save space as some people want a really small decompressor */
  55     LZO_VERSION_STRING;
  56 #else
  57     "\r\n\n"
  58     "LZO data compression library.\n"
  59     "$Copyright: LZO (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 Markus Franz Xaver Johannes Oberhumer\n"
  60     "<markus@oberhumer.com>\n"
  61     "http://www.oberhumer.com $\n\n"
  62     "$Id: LZO version: v" LZO_VERSION_STRING ", " LZO_VERSION_DATE " $\n"
  63     "$Built: " __DATE__ " " __TIME__ " $\n"
  64     "$Info: " LZO_INFO_STRING " $\n";
  65 #endif
  66
  67
  68 LZO_PUBLIC(const lzo_bytep)
  69 lzo_copyright(void)
  70 {
  71 #if (LZO_OS_DOS16 && LZO_CC_TURBOC)
  72     return (lzo_voidp) __lzo_copyright;
  73 #else
  74     return (const lzo_bytep) __lzo_copyright;
  75 #endif
  76 }
  77
  78 LZO_PUBLIC(unsigned)
  79 lzo_version(void)
  80 {
  81     return LZO_VERSION;
  82 }
  83
  84 LZO_PUBLIC(const char *)
  85 lzo_version_string(void)
  86 {
  87     return LZO_VERSION_STRING;
  88 }
  89
  90 LZO_PUBLIC(const char *)
  91 lzo_version_date(void)
  92 {
  93     return LZO_VERSION_DATE;
  94 }
  95
  96 LZO_PUBLIC(const lzo_charp)
  97 _lzo_version_string(void)
  98 {
  99     return LZO_VERSION_STRING;
 100 }
 101
 102 LZO_PUBLIC(const lzo_charp)
 103 _lzo_version_date(void)
 104 {
 105     return LZO_VERSION_DATE;
 106 }
 107
 108
 109 /***********************************************************************
 110 // adler32 checksum
 111 // adapted from free code by Mark Adler <madler@alumni.caltech.edu>
 112 // see http://www.zlib.org/
 113 ************************************************************************/
 114
 115 #define LZO_BASE 65521u /* largest prime smaller than 65536 */
 116 #define LZO_NMAX 5552
 117 /* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */
 118
 119 #define LZO_DO1(buf,i)  s1 += buf[i]; s2 += s1
 120 #define LZO_DO2(buf,i)  LZO_DO1(buf,i); LZO_DO1(buf,i+1);
 121 #define LZO_DO4(buf,i)  LZO_DO2(buf,i); LZO_DO2(buf,i+2);
 122 #define LZO_DO8(buf,i)  LZO_DO4(buf,i); LZO_DO4(buf,i+4);
 123 #define LZO_DO16(buf,i) LZO_DO8(buf,i); LZO_DO8(buf,i+8);
 124
 125 LZO_PUBLIC(lzo_uint32)
 126 lzo_adler32(lzo_uint32 adler, const lzo_bytep buf, lzo_uint len)
 127 {
 128     lzo_uint32 s1 = adler & 0xffff;
 129     lzo_uint32 s2 = (adler >> 16) & 0xffff;
 130     unsigned k;
 131
 132     if (buf == NULL)
 133         return 1;
 134
 135     while (len > 0)
 136     {
 137         k = len < LZO_NMAX ? (unsigned) len : LZO_NMAX;
 138         len -= k;
 139         if (k >= 16) do
 140         {
 141             LZO_DO16(buf,0);
 142             buf += 16;
 143             k -= 16;
 144         } while (k >= 16);
 145         if (k != 0) do
 146         {
 147             s1 += *buf++;
 148             s2 += s1;
 149         } while (--k > 0);
 150         s1 %= LZO_BASE;
 151         s2 %= LZO_BASE;
 152     }
 153     return (s2 << 16) | s1;
 154 }
 155
 156 #undef LZO_DO1
 157 #undef LZO_DO2
 158 #undef LZO_DO4
 159 #undef LZO_DO8
 160 #undef LZO_DO16
 161
 162
 163 /*
 164 vi:ts=4:et
 165 */