crc.c

   1 /* DLIFE Copyright (C) 2000 Richard W.M. Jones <rich@annexia.org>
   2  * and other authors listed in the ``AUTHORS'' file.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  17  *
  18  * $Id: crc.c,v 1.1 2002/04/05 14:40:25 rich Exp $
  19  */
  20
  21 #include "config.h"
  22
  23 #include "crc.h"
  24
  25 /* Code to do 32-bit CRCs.
  26  * Derived from code by Julian Seward (sewardj@cs.man.ac.uk)
  27  * Written by Richard W.M. Jones (rich@annexia.org)
  28  * Note original copyright messages below ...
  29  */
  30
  31 /*--
  32   Copyright (C) 1996 by Julian Seward.
  33      Department of Computer Science, University of Manchester,
  34      Oxford Road, Manchester M13 9PL, UK.
  35      email: sewardj@cs.man.ac.uk
  36 --*/
  37
  38 /*---------------------------------------------------*/
  39 /*--- 32-bit CRC grunge                           ---*/
  40 /*---------------------------------------------------*/
  41
  42 /*--
  43   I think this is an implementation of the AUTODIN-II,
  44   Ethernet & FDDI 32-bit CRC standard.  Vaguely derived
  45   from code by Rob Warnock, in Section 51 of the
  46   comp.compression FAQ.
  47 --*/
  48
  49 static crc_t crc32Table[256] = {
  50
  51    /*-- Ugly, innit? --*/
  52
  53    0x00000000L, 0x04c11db7L, 0x09823b6eL, 0x0d4326d9L,
  54    0x130476dcL, 0x17c56b6bL, 0x1a864db2L, 0x1e475005L,
  55    0x2608edb8L, 0x22c9f00fL, 0x2f8ad6d6L, 0x2b4bcb61L,
  56    0x350c9b64L, 0x31cd86d3L, 0x3c8ea00aL, 0x384fbdbdL,
  57    0x4c11db70L, 0x48d0c6c7L, 0x4593e01eL, 0x4152fda9L,
  58    0x5f15adacL, 0x5bd4b01bL, 0x569796c2L, 0x52568b75L,
  59    0x6a1936c8L, 0x6ed82b7fL, 0x639b0da6L, 0x675a1011L,
  60    0x791d4014L, 0x7ddc5da3L, 0x709f7b7aL, 0x745e66cdL,
  61    0x9823b6e0L, 0x9ce2ab57L, 0x91a18d8eL, 0x95609039L,
  62    0x8b27c03cL, 0x8fe6dd8bL, 0x82a5fb52L, 0x8664e6e5L,
  63    0xbe2b5b58L, 0xbaea46efL, 0xb7a96036L, 0xb3687d81L,
  64    0xad2f2d84L, 0xa9ee3033L, 0xa4ad16eaL, 0xa06c0b5dL,
  65    0xd4326d90L, 0xd0f37027L, 0xddb056feL, 0xd9714b49L,
  66    0xc7361b4cL, 0xc3f706fbL, 0xceb42022L, 0xca753d95L,
  67    0xf23a8028L, 0xf6fb9d9fL, 0xfbb8bb46L, 0xff79a6f1L,
  68    0xe13ef6f4L, 0xe5ffeb43L, 0xe8bccd9aL, 0xec7dd02dL,
  69    0x34867077L, 0x30476dc0L, 0x3d044b19L, 0x39c556aeL,
  70    0x278206abL, 0x23431b1cL, 0x2e003dc5L, 0x2ac12072L,
  71    0x128e9dcfL, 0x164f8078L, 0x1b0ca6a1L, 0x1fcdbb16L,
  72    0x018aeb13L, 0x054bf6a4L, 0x0808d07dL, 0x0cc9cdcaL,
  73    0x7897ab07L, 0x7c56b6b0L, 0x71159069L, 0x75d48ddeL,
  74    0x6b93dddbL, 0x6f52c06cL, 0x6211e6b5L, 0x66d0fb02L,
  75    0x5e9f46bfL, 0x5a5e5b08L, 0x571d7dd1L, 0x53dc6066L,
  76    0x4d9b3063L, 0x495a2dd4L, 0x44190b0dL, 0x40d816baL,
  77    0xaca5c697L, 0xa864db20L, 0xa527fdf9L, 0xa1e6e04eL,
  78    0xbfa1b04bL, 0xbb60adfcL, 0xb6238b25L, 0xb2e29692L,
  79    0x8aad2b2fL, 0x8e6c3698L, 0x832f1041L, 0x87ee0df6L,
  80    0x99a95df3L, 0x9d684044L, 0x902b669dL, 0x94ea7b2aL,
  81    0xe0b41de7L, 0xe4750050L, 0xe9362689L, 0xedf73b3eL,
  82    0xf3b06b3bL, 0xf771768cL, 0xfa325055L, 0xfef34de2L,
  83    0xc6bcf05fL, 0xc27dede8L, 0xcf3ecb31L, 0xcbffd686L,
  84    0xd5b88683L, 0xd1799b34L, 0xdc3abdedL, 0xd8fba05aL,
  85    0x690ce0eeL, 0x6dcdfd59L, 0x608edb80L, 0x644fc637L,
  86    0x7a089632L, 0x7ec98b85L, 0x738aad5cL, 0x774bb0ebL,
  87    0x4f040d56L, 0x4bc510e1L, 0x46863638L, 0x42472b8fL,
  88    0x5c007b8aL, 0x58c1663dL, 0x558240e4L, 0x51435d53L,
  89    0x251d3b9eL, 0x21dc2629L, 0x2c9f00f0L, 0x285e1d47L,
  90    0x36194d42L, 0x32d850f5L, 0x3f9b762cL, 0x3b5a6b9bL,
  91    0x0315d626L, 0x07d4cb91L, 0x0a97ed48L, 0x0e56f0ffL,
  92    0x1011a0faL, 0x14d0bd4dL, 0x19939b94L, 0x1d528623L,
  93    0xf12f560eL, 0xf5ee4bb9L, 0xf8ad6d60L, 0xfc6c70d7L,
  94    0xe22b20d2L, 0xe6ea3d65L, 0xeba91bbcL, 0xef68060bL,
  95    0xd727bbb6L, 0xd3e6a601L, 0xdea580d8L, 0xda649d6fL,
  96    0xc423cd6aL, 0xc0e2d0ddL, 0xcda1f604L, 0xc960ebb3L,
  97    0xbd3e8d7eL, 0xb9ff90c9L, 0xb4bcb610L, 0xb07daba7L,
  98    0xae3afba2L, 0xaafbe615L, 0xa7b8c0ccL, 0xa379dd7bL,
  99    0x9b3660c6L, 0x9ff77d71L, 0x92b45ba8L, 0x9675461fL,
 100    0x8832161aL, 0x8cf30badL, 0x81b02d74L, 0x857130c3L,
 101    0x5d8a9099L, 0x594b8d2eL, 0x5408abf7L, 0x50c9b640L,
 102    0x4e8ee645L, 0x4a4ffbf2L, 0x470cdd2bL, 0x43cdc09cL,
 103    0x7b827d21L, 0x7f436096L, 0x7200464fL, 0x76c15bf8L,
 104    0x68860bfdL, 0x6c47164aL, 0x61043093L, 0x65c52d24L,
 105    0x119b4be9L, 0x155a565eL, 0x18197087L, 0x1cd86d30L,
 106    0x029f3d35L, 0x065e2082L, 0x0b1d065bL, 0x0fdc1becL,
 107    0x3793a651L, 0x3352bbe6L, 0x3e119d3fL, 0x3ad08088L,
 108    0x2497d08dL, 0x2056cd3aL, 0x2d15ebe3L, 0x29d4f654L,
 109    0xc5a92679L, 0xc1683bceL, 0xcc2b1d17L, 0xc8ea00a0L,
 110    0xd6ad50a5L, 0xd26c4d12L, 0xdf2f6bcbL, 0xdbee767cL,
 111    0xe3a1cbc1L, 0xe760d676L, 0xea23f0afL, 0xeee2ed18L,
 112    0xf0a5bd1dL, 0xf464a0aaL, 0xf9278673L, 0xfde69bc4L,
 113    0x89b8fd09L, 0x8d79e0beL, 0x803ac667L, 0x84fbdbd0L,
 114    0x9abc8bd5L, 0x9e7d9662L, 0x933eb0bbL, 0x97ffad0cL,
 115    0xafb010b1L, 0xab710d06L, 0xa6322bdfL, 0xa2f33668L,
 116    0xbcb4666dL, 0xb8757bdaL, 0xb5365d03L, 0xb1f740b4L
 117 };
 118
 119 #define UPDATE_CRC(crcVar,cha)                  \
 120 {                                               \
 121    crcVar = (crcVar << 8) ^                     \
 122             crc32Table[(crcVar >> 24) ^         \
 123                        (cha)];                  \
 124 }
 125
 126 inline crc_t
 127 incr_compute_crc32 (crc_t crc, byte_t *p, size_t len)
 128 {
 129   while (len)
 130     {
 131       UPDATE_CRC (crc, *p);
 132       p ++;
 133       len --;
 134     }
 135   return crc;
 136 }
 137
 138 crc_t
 139 compute_crc32 (byte_t *p, size_t len)
 140 {
 141   return incr_compute_crc32 (0xffffffffUL, p, len);
 142 }