Filters/HtmlAgilityPack/crc32.cs

   1 // HtmlAgilityPack V1.0 - Simon Mourier <simonm@microsoft.com>
   2
   3 /*
   4 Copyright (C) 2003 Simon Mourier <simonm@microsoft.com>
   5 All rights reserved.
   6
   7 Redistribution and use in source and binary forms, with or without
   8 modification, are permitted provided that the following conditions
   9 are met:
  10 1. Redistributions of source code must retain the above copyright
  11    notice, this list of conditions and the following disclaimer.
  12 2. Redistributions in binary form must reproduce the above copyright
  13    notice, this list of conditions and the following disclaimer in the
  14    documentation and/or other materials provided with the distribution.
  15 3. The name of the author may not be used to endorse or promote products
  16    derived from this software without specific prior written permission.
  17
  18 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  19 IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  20 OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  21 IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  22 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  23 NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  24 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  25 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  26 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  27 THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28 */
  29
  30 using System;
  31 using System.IO;
  32
  33 namespace HtmlAgilityPack
  34 {
  35         /// <summary>
  36         /// A utility class to compute CRC32.
  37         /// </summary>
  38         public class Crc32
  39         {
  40                 private uint _crc32 = 0;
  41                 static private uint[] crc_32_tab =  // CRC polynomial 0xedb88320
  42                         {
  43                                 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
  44                                 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
  45                                 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
  46                                 0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
  47                                 0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
  48                                 0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
  49                                 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c,
  50                                 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
  51                                 0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
  52                                 0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
  53                                 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106,
  54                                 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
  55                                 0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
  56                                 0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
  57                                 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
  58                                 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
  59                                 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
  60                                 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
  61                                 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
  62                                 0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
  63                                 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
  64                                 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
  65                                 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
  66                                 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
  67                                 0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
  68                                 0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
  69                                 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
  70                                 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
  71                                 0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
  72                                 0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
  73                                 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
  74                                 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
  75                                 0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
  76                                 0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
  77                                 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
  78                                 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
  79                                 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
  80                                 0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
  81                                 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
  82                                 0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
  83                                 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
  84                                 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
  85                                 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
  86                         };
  87
  88                 static private uint UPDC32(byte octet, uint crc)
  89                 {
  90                         return (crc_32_tab[((crc)^((byte)octet)) & 0xff] ^ ((crc) >> 8));
  91                 }
  92
  93                 internal uint CheckSum
  94                 {
  95                         get
  96                         {
  97                                 return _crc32;
  98                         }
  99                         set
 100                         {
 101                                 _crc32 = value;
 102                         }
 103                 }
 104
 105                 internal uint AddToCRC32(int c)
 106                 {
 107                         return AddToCRC32((ushort)c);
 108                 }
 109
 110                 internal uint AddToCRC32(ushort c)
 111                 {
 112                         byte lowByte, hiByte;
 113                         lowByte = (byte)(c & 0x00ff);
 114                         hiByte = (byte)(c >> 8);
 115                         _crc32 = UPDC32(hiByte, _crc32);
 116                         _crc32 = UPDC32(lowByte, _crc32);
 117                         return ~_crc32;
 118                 }
 119
 120                 /// <summary>
 121                 /// Compute a checksum for a given string.
 122                 /// </summary>
 123                 /// <param name="text">The string to compute the checksum for.</param>
 124                 /// <returns>The computed checksum.</returns>
 125                 static public uint CRC32String(string text)
 126                 {
 127                         uint oldcrc32;
 128                         oldcrc32 = 0xFFFFFFFF;
 129                         int len = text.Length;
 130                         ushort uCharVal;
 131                         byte lowByte, hiByte;
 132
 133                         for ( int i=0; len>0; i++)
 134                         {
 135                                 --len;
 136                                 uCharVal = text[len];
 137                                 unchecked
 138                                 {
 139                                         lowByte = (byte)(uCharVal & 0x00ff);
 140                                         hiByte = (byte)(uCharVal >> 8);
 141                                 }
 142                                 oldcrc32 = UPDC32(hiByte, oldcrc32);
 143                                 oldcrc32 = UPDC32(lowByte, oldcrc32);
 144                         }
 145
 146                         return ~oldcrc32;
 147                 }
 148
 149                 /// <summary>
 150                 /// Compute a checksum for a given array of bytes.
 151                 /// </summary>
 152                 /// <param name="bytes">The array of bytes to compute the checksum for.</param>
 153                 /// <returns>The computed checksum.</returns>
 154                 static public uint CRC32Bytes(byte[] bytes)
 155                 {
 156                         uint oldcrc32;
 157                         oldcrc32 = 0xFFFFFFFF;
 158                         int len = bytes.Length;
 159
 160                         for ( int i=0; len>0; i++)
 161                         {
 162                                 --len;
 163                                 oldcrc32 = UPDC32(bytes[len], oldcrc32);
 164                         }
 165                         return ~oldcrc32;
 166                 }
 167         }
 168 }