CRC.cs 8.3 KB

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  1. /*
  2. * Copyright 2001,2004-2005 The Apache Software Foundation
  3. *
  4. * Licensed under the Apache License, Version 2.0 (the "License");
  5. * you may not use this file except in compliance with the License.
  6. * You may obtain a copy of the License at
  7. *
  8. * http://www.apache.org/licenses/LICENSE-2.0
  9. *
  10. * Unless required by applicable law or agreed to in writing, software
  11. * distributed under the License is distributed on an "AS IS" BASIS,
  12. * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13. * See the License for the specific language governing permissions and
  14. * limitations under the License.
  15. */
  16. /*
  17. * This package is based on the work done by Keiron Liddle), Aftex Software
  18. * <keiron@aftexsw.com> to whom the Ant project is very grateful for his
  19. * great code.
  20. */
  21. namespace SharpCompress.Compressors.BZip2
  22. {
  23. /**
  24. * A simple class the hold and calculate the CRC for sanity checking
  25. * of the data.
  26. *
  27. * @author <a href="mailto:keiron@aftexsw.com">Keiron Liddle</a>
  28. */
  29. internal class CRC
  30. {
  31. public static int[] crc32Table =
  32. {
  33. 0x00000000, 0x04c11db7, 0x09823b6e,
  34. 0x0d4326d9,
  35. 0x130476dc, 0x17c56b6b, 0x1a864db2,
  36. 0x1e475005,
  37. 0x2608edb8, 0x22c9f00f, 0x2f8ad6d6,
  38. 0x2b4bcb61,
  39. 0x350c9b64, 0x31cd86d3, 0x3c8ea00a,
  40. 0x384fbdbd,
  41. 0x4c11db70, 0x48d0c6c7, 0x4593e01e,
  42. 0x4152fda9,
  43. 0x5f15adac, 0x5bd4b01b, 0x569796c2,
  44. 0x52568b75,
  45. 0x6a1936c8, 0x6ed82b7f, 0x639b0da6,
  46. 0x675a1011,
  47. 0x791d4014, 0x7ddc5da3, 0x709f7b7a,
  48. 0x745e66cd,
  49. unchecked((int)0x9823b6e0), unchecked((int)0x9ce2ab57), unchecked((int)0x91a18d8e),
  50. unchecked((int)0x95609039),
  51. unchecked((int)0x8b27c03c), unchecked((int)0x8fe6dd8b), unchecked((int)0x82a5fb52),
  52. unchecked((int)0x8664e6e5),
  53. unchecked((int)0xbe2b5b58), unchecked((int)0xbaea46ef), unchecked((int)0xb7a96036),
  54. unchecked((int)0xb3687d81),
  55. unchecked((int)0xad2f2d84), unchecked((int)0xa9ee3033), unchecked((int)0xa4ad16ea),
  56. unchecked((int)0xa06c0b5d),
  57. unchecked((int)0xd4326d90), unchecked((int)0xd0f37027), unchecked((int)0xddb056fe),
  58. unchecked((int)0xd9714b49),
  59. unchecked((int)0xc7361b4c), unchecked((int)0xc3f706fb), unchecked((int)0xceb42022),
  60. unchecked((int)0xca753d95),
  61. unchecked((int)0xf23a8028), unchecked((int)0xf6fb9d9f), unchecked((int)0xfbb8bb46),
  62. unchecked((int)0xff79a6f1),
  63. unchecked((int)0xe13ef6f4), unchecked((int)0xe5ffeb43), unchecked((int)0xe8bccd9a),
  64. unchecked((int)0xec7dd02d),
  65. 0x34867077, 0x30476dc0, 0x3d044b19,
  66. 0x39c556ae,
  67. 0x278206ab, 0x23431b1c, 0x2e003dc5,
  68. 0x2ac12072,
  69. 0x128e9dcf, 0x164f8078, 0x1b0ca6a1,
  70. 0x1fcdbb16,
  71. 0x018aeb13, 0x054bf6a4, 0x0808d07d,
  72. 0x0cc9cdca,
  73. 0x7897ab07, 0x7c56b6b0, 0x71159069,
  74. 0x75d48dde,
  75. 0x6b93dddb, 0x6f52c06c, 0x6211e6b5,
  76. 0x66d0fb02,
  77. 0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1,
  78. 0x53dc6066,
  79. 0x4d9b3063, 0x495a2dd4, 0x44190b0d,
  80. 0x40d816ba,
  81. unchecked((int)0xaca5c697), unchecked((int)0xa864db20), unchecked((int)0xa527fdf9),
  82. unchecked((int)0xa1e6e04e),
  83. unchecked((int)0xbfa1b04b), unchecked((int)0xbb60adfc), unchecked((int)0xb6238b25),
  84. unchecked((int)0xb2e29692),
  85. unchecked((int)0x8aad2b2f), unchecked((int)0x8e6c3698), unchecked((int)0x832f1041),
  86. unchecked((int)0x87ee0df6),
  87. unchecked((int)0x99a95df3), unchecked((int)0x9d684044), unchecked((int)0x902b669d),
  88. unchecked((int)0x94ea7b2a),
  89. unchecked((int)0xe0b41de7), unchecked((int)0xe4750050), unchecked((int)0xe9362689),
  90. unchecked((int)0xedf73b3e),
  91. unchecked((int)0xf3b06b3b), unchecked((int)0xf771768c), unchecked((int)0xfa325055),
  92. unchecked((int)0xfef34de2),
  93. unchecked((int)0xc6bcf05f), unchecked((int)0xc27dede8), unchecked((int)0xcf3ecb31),
  94. unchecked((int)0xcbffd686),
  95. unchecked((int)0xd5b88683), unchecked((int)0xd1799b34), unchecked((int)0xdc3abded),
  96. unchecked((int)0xd8fba05a),
  97. 0x690ce0ee, 0x6dcdfd59, 0x608edb80,
  98. 0x644fc637,
  99. 0x7a089632, 0x7ec98b85, 0x738aad5c,
  100. 0x774bb0eb,
  101. 0x4f040d56, 0x4bc510e1, 0x46863638,
  102. 0x42472b8f,
  103. 0x5c007b8a, 0x58c1663d, 0x558240e4,
  104. 0x51435d53,
  105. 0x251d3b9e, 0x21dc2629, 0x2c9f00f0,
  106. 0x285e1d47,
  107. 0x36194d42, 0x32d850f5, 0x3f9b762c,
  108. 0x3b5a6b9b,
  109. 0x0315d626, 0x07d4cb91, 0x0a97ed48,
  110. 0x0e56f0ff,
  111. 0x1011a0fa, 0x14d0bd4d, 0x19939b94,
  112. 0x1d528623,
  113. unchecked((int)0xf12f560e), unchecked((int)0xf5ee4bb9), unchecked((int)0xf8ad6d60),
  114. unchecked((int)0xfc6c70d7),
  115. unchecked((int)0xe22b20d2), unchecked((int)0xe6ea3d65), unchecked((int)0xeba91bbc),
  116. unchecked((int)0xef68060b),
  117. unchecked((int)0xd727bbb6), unchecked((int)0xd3e6a601), unchecked((int)0xdea580d8),
  118. unchecked((int)0xda649d6f),
  119. unchecked((int)0xc423cd6a), unchecked((int)0xc0e2d0dd), unchecked((int)0xcda1f604),
  120. unchecked((int)0xc960ebb3),
  121. unchecked((int)0xbd3e8d7e), unchecked((int)0xb9ff90c9), unchecked((int)0xb4bcb610),
  122. unchecked((int)0xb07daba7),
  123. unchecked((int)0xae3afba2), unchecked((int)0xaafbe615), unchecked((int)0xa7b8c0cc),
  124. unchecked((int)0xa379dd7b),
  125. unchecked((int)0x9b3660c6), unchecked((int)0x9ff77d71), unchecked((int)0x92b45ba8),
  126. unchecked((int)0x9675461f),
  127. unchecked((int)0x8832161a), unchecked((int)0x8cf30bad), unchecked((int)0x81b02d74),
  128. unchecked((int)0x857130c3),
  129. 0x5d8a9099, 0x594b8d2e, 0x5408abf7,
  130. 0x50c9b640,
  131. 0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b,
  132. 0x43cdc09c,
  133. 0x7b827d21, 0x7f436096, 0x7200464f,
  134. 0x76c15bf8,
  135. 0x68860bfd, 0x6c47164a, 0x61043093,
  136. 0x65c52d24,
  137. 0x119b4be9, 0x155a565e, 0x18197087,
  138. 0x1cd86d30,
  139. 0x029f3d35, 0x065e2082, 0x0b1d065b,
  140. 0x0fdc1bec,
  141. 0x3793a651, 0x3352bbe6, 0x3e119d3f,
  142. 0x3ad08088,
  143. 0x2497d08d, 0x2056cd3a, 0x2d15ebe3,
  144. 0x29d4f654,
  145. unchecked((int)0xc5a92679), unchecked((int)0xc1683bce), unchecked((int)0xcc2b1d17),
  146. unchecked((int)0xc8ea00a0),
  147. unchecked((int)0xd6ad50a5), unchecked((int)0xd26c4d12), unchecked((int)0xdf2f6bcb),
  148. unchecked((int)0xdbee767c),
  149. unchecked((int)0xe3a1cbc1), unchecked((int)0xe760d676), unchecked((int)0xea23f0af),
  150. unchecked((int)0xeee2ed18),
  151. unchecked((int)0xf0a5bd1d), unchecked((int)0xf464a0aa), unchecked((int)0xf9278673),
  152. unchecked((int)0xfde69bc4),
  153. unchecked((int)0x89b8fd09), unchecked((int)0x8d79e0be), unchecked((int)0x803ac667),
  154. unchecked((int)0x84fbdbd0),
  155. unchecked((int)0x9abc8bd5), unchecked((int)0x9e7d9662), unchecked((int)0x933eb0bb),
  156. unchecked((int)0x97ffad0c),
  157. unchecked((int)0xafb010b1), unchecked((int)0xab710d06), unchecked((int)0xa6322bdf),
  158. unchecked((int)0xa2f33668),
  159. unchecked((int)0xbcb4666d), unchecked((int)0xb8757bda), unchecked((int)0xb5365d03),
  160. unchecked((int)0xb1f740b4)
  161. };
  162. public CRC()
  163. {
  164. InitialiseCRC();
  165. }
  166. internal void InitialiseCRC()
  167. {
  168. globalCrc = unchecked((int)0xffffffff);
  169. }
  170. internal int GetFinalCRC()
  171. {
  172. return ~globalCrc;
  173. }
  174. internal int GetGlobalCRC()
  175. {
  176. return globalCrc;
  177. }
  178. internal void SetGlobalCRC(int newCrc)
  179. {
  180. globalCrc = newCrc;
  181. }
  182. internal void UpdateCRC(int inCh)
  183. {
  184. int temp = (globalCrc >> 24) ^ inCh;
  185. if (temp < 0)
  186. {
  187. temp = 256 + temp;
  188. }
  189. globalCrc = (globalCrc << 8) ^ crc32Table[temp];
  190. }
  191. internal int globalCrc;
  192. }
  193. }