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crc32.c 7.7 KB

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  1. /*
  2. * This file is derived from crc32.c from the zlib-1.1.3 distribution
  3. * by Jean-loup Gailly and Mark Adler.
  4. */
  5. /* crc32.c -- compute the CRC-32 of a data stream
  6. * Copyright (C) 1995-1998 Mark Adler
  7. * For conditions of distribution and use, see copyright notice in zlib.h
  8. */
  9. #define USE_HOSTCC
  10. #ifndef USE_HOSTCC /* Shut down "ANSI does not permit..." warnings */
  11. #include <common.h> /* to get command definitions like CFG_CMD_JFFS2 */
  12. #endif
  13. #include "zlib.h"
  14. #define local static
  15. #define ZEXPORT /* empty */
  16. unsigned long crc32 (unsigned long, const unsigned char *, unsigned int);
  17. #ifdef DYNAMIC_CRC_TABLE
  18. local int crc_table_empty = 1;
  19. local uLongf crc_table[256];
  20. local void make_crc_table OF((void));
  21. /*
  22. Generate a table for a byte-wise 32-bit CRC calculation on the polynomial:
  23. x^32+x^26+x^23+x^22+x^16+x^12+x^11+x^10+x^8+x^7+x^5+x^4+x^2+x+1.
  24. Polynomials over GF(2) are represented in binary, one bit per coefficient,
  25. with the lowest powers in the most significant bit. Then adding polynomials
  26. is just exclusive-or, and multiplying a polynomial by x is a right shift by
  27. one. If we call the above polynomial p, and represent a byte as the
  28. polynomial q, also with the lowest power in the most significant bit (so the
  29. byte 0xb1 is the polynomial x^7+x^3+x+1), then the CRC is (q*x^32) mod p,
  30. where a mod b means the remainder after dividing a by b.
  31. This calculation is done using the shift-register method of multiplying and
  32. taking the remainder. The register is initialized to zero, and for each
  33. incoming bit, x^32 is added mod p to the register if the bit is a one (where
  34. x^32 mod p is p+x^32 = x^26+...+1), and the register is multiplied mod p by
  35. x (which is shifting right by one and adding x^32 mod p if the bit shifted
  36. out is a one). We start with the highest power (least significant bit) of
  37. q and repeat for all eight bits of q.
  38. The table is simply the CRC of all possible eight bit values. This is all
  39. the information needed to generate CRC's on data a byte at a time for all
  40. combinations of CRC register values and incoming bytes.
  41. */
  42. local void make_crc_table()
  43. {
  44. uLong c;
  45. int n, k;
  46. uLong poly; /* polynomial exclusive-or pattern */
  47. /* terms of polynomial defining this crc (except x^32): */
  48. static const Byte p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26};
  49. /* make exclusive-or pattern from polynomial (0xedb88320L) */
  50. poly = 0L;
  51. for (n = 0; n < sizeof(p)/sizeof(Byte); n++)
  52. poly |= 1L << (31 - p[n]);
  53. for (n = 0; n < 256; n++)
  54. {
  55. c = (uLong)n;
  56. for (k = 0; k < 8; k++)
  57. c = c & 1 ? poly ^ (c >> 1) : c >> 1;
  58. crc_table[n] = c;
  59. }
  60. crc_table_empty = 0;
  61. }
  62. #else
  63. /* ========================================================================
  64. * Table of CRC-32's of all single-byte values (made by make_crc_table)
  65. */
  66. local const uLongf crc_table[256] = {
  67. 0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L,
  68. 0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0x0edb8832L, 0x79dcb8a4L,
  69. 0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L,
  70. 0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL,
  71. 0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L,
  72. 0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L,
  73. 0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L,
  74. 0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
  75. 0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L,
  76. 0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL,
  77. 0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L,
  78. 0xb8bda50fL, 0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L,
  79. 0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL, 0x76dc4190L,
  80. 0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL,
  81. 0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0x0f00f934L, 0x9609a88eL,
  82. 0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
  83. 0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL,
  84. 0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L,
  85. 0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L,
  86. 0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L,
  87. 0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL,
  88. 0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L,
  89. 0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L,
  90. 0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
  91. 0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L,
  92. 0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, 0x9abfb3b6L,
  93. 0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L,
  94. 0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L,
  95. 0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L, 0xf00f9344L,
  96. 0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL,
  97. 0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, 0x89d32be0L, 0x10da7a5aL,
  98. 0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
  99. 0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L,
  100. 0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL,
  101. 0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL,
  102. 0x4669be79L, 0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L,
  103. 0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL, 0xc5ba3bbeL,
  104. 0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L,
  105. 0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL,
  106. 0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
  107. 0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL,
  108. 0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L, 0x86d3d2d4L, 0xf1d4e242L,
  109. 0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L,
  110. 0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL,
  111. 0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L,
  112. 0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L,
  113. 0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L,
  114. 0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
  115. 0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L,
  116. 0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, 0xc4614ab8L,
  117. 0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL,
  118. 0x2d02ef8dL
  119. };
  120. #endif
  121. #if 0
  122. /* =========================================================================
  123. * This function can be used by asm versions of crc32()
  124. */
  125. const uLongf * ZEXPORT get_crc_table()
  126. {
  127. #ifdef DYNAMIC_CRC_TABLE
  128. if (crc_table_empty) make_crc_table();
  129. #endif
  130. return (const uLongf *)crc_table;
  131. }
  132. #endif
  133. /* ========================================================================= */
  134. #define DO1(buf) crc = crc_table[((int)crc ^ (*buf++)) & 0xff] ^ (crc >> 8);
  135. #define DO2(buf) DO1(buf); DO1(buf);
  136. #define DO4(buf) DO2(buf); DO2(buf);
  137. #define DO8(buf) DO4(buf); DO4(buf);
  138. /* ========================================================================= */
  139. uLong ZEXPORT crc32(crc, buf, len)
  140. uLong crc;
  141. const Bytef *buf;
  142. uInt len;
  143. {
  144. #ifdef DYNAMIC_CRC_TABLE
  145. if (crc_table_empty)
  146. make_crc_table();
  147. #endif
  148. crc = crc ^ 0xffffffffL;
  149. while (len >= 8)
  150. {
  151. DO8(buf);
  152. len -= 8;
  153. }
  154. if (len) do {
  155. DO1(buf);
  156. } while (--len);
  157. return crc ^ 0xffffffffL;
  158. }
  159. #if (CONFIG_COMMANDS & CFG_CMD_JFFS2) || \
  160. ((CONFIG_COMMANDS & CFG_CMD_NAND) && !defined(CFG_NAND_LEGACY))
  161. /* No ones complement version. JFFS2 (and other things ?)
  162. * don't use ones compliment in their CRC calculations.
  163. */
  164. uLong ZEXPORT crc32_no_comp(uLong crc, const Bytef *buf, uInt len)
  165. {
  166. #ifdef DYNAMIC_CRC_TABLE
  167. if (crc_table_empty)
  168. make_crc_table();
  169. #endif
  170. while (len >= 8)
  171. {
  172. DO8(buf);
  173. len -= 8;
  174. }
  175. if (len) do {
  176. DO1(buf);
  177. } while (--len);
  178. return crc;
  179. }
  180. #endif /* CFG_CMD_JFFS2 */