hashes.c 3.5 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177
  1. /*
  2. * Keyed 32-bit hash function using TEA in a Davis-Meyer function
  3. * H0 = Key
  4. * Hi = E Mi(Hi-1) + Hi-1
  5. *
  6. * (see Applied Cryptography, 2nd edition, p448).
  7. *
  8. * Jeremy Fitzhardinge <jeremy@zip.com.au> 1998
  9. *
  10. * Jeremy has agreed to the contents of reiserfs/README. -Hans
  11. * Yura's function is added (04/07/2000)
  12. */
  13. #include <linux/kernel.h>
  14. #include "reiserfs.h"
  15. #include <asm/types.h>
  16. #define DELTA 0x9E3779B9
  17. #define FULLROUNDS 10 /* 32 is overkill, 16 is strong crypto */
  18. #define PARTROUNDS 6 /* 6 gets complete mixing */
  19. /* a, b, c, d - data; h0, h1 - accumulated hash */
  20. #define TEACORE(rounds) \
  21. do { \
  22. u32 sum = 0; \
  23. int n = rounds; \
  24. u32 b0, b1; \
  25. \
  26. b0 = h0; \
  27. b1 = h1; \
  28. \
  29. do \
  30. { \
  31. sum += DELTA; \
  32. b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b); \
  33. b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d); \
  34. } while(--n); \
  35. \
  36. h0 += b0; \
  37. h1 += b1; \
  38. } while(0)
  39. u32 keyed_hash(const signed char *msg, int len)
  40. {
  41. u32 k[] = { 0x9464a485, 0x542e1a94, 0x3e846bff, 0xb75bcfc3 };
  42. u32 h0 = k[0], h1 = k[1];
  43. u32 a, b, c, d;
  44. u32 pad;
  45. int i;
  46. /* assert(len >= 0 && len < 256); */
  47. pad = (u32) len | ((u32) len << 8);
  48. pad |= pad << 16;
  49. while (len >= 16) {
  50. a = (u32) msg[0] |
  51. (u32) msg[1] << 8 | (u32) msg[2] << 16 | (u32) msg[3] << 24;
  52. b = (u32) msg[4] |
  53. (u32) msg[5] << 8 | (u32) msg[6] << 16 | (u32) msg[7] << 24;
  54. c = (u32) msg[8] |
  55. (u32) msg[9] << 8 |
  56. (u32) msg[10] << 16 | (u32) msg[11] << 24;
  57. d = (u32) msg[12] |
  58. (u32) msg[13] << 8 |
  59. (u32) msg[14] << 16 | (u32) msg[15] << 24;
  60. TEACORE(PARTROUNDS);
  61. len -= 16;
  62. msg += 16;
  63. }
  64. if (len >= 12) {
  65. a = (u32) msg[0] |
  66. (u32) msg[1] << 8 | (u32) msg[2] << 16 | (u32) msg[3] << 24;
  67. b = (u32) msg[4] |
  68. (u32) msg[5] << 8 | (u32) msg[6] << 16 | (u32) msg[7] << 24;
  69. c = (u32) msg[8] |
  70. (u32) msg[9] << 8 |
  71. (u32) msg[10] << 16 | (u32) msg[11] << 24;
  72. d = pad;
  73. for (i = 12; i < len; i++) {
  74. d <<= 8;
  75. d |= msg[i];
  76. }
  77. } else if (len >= 8) {
  78. a = (u32) msg[0] |
  79. (u32) msg[1] << 8 | (u32) msg[2] << 16 | (u32) msg[3] << 24;
  80. b = (u32) msg[4] |
  81. (u32) msg[5] << 8 | (u32) msg[6] << 16 | (u32) msg[7] << 24;
  82. c = d = pad;
  83. for (i = 8; i < len; i++) {
  84. c <<= 8;
  85. c |= msg[i];
  86. }
  87. } else if (len >= 4) {
  88. a = (u32) msg[0] |
  89. (u32) msg[1] << 8 | (u32) msg[2] << 16 | (u32) msg[3] << 24;
  90. b = c = d = pad;
  91. for (i = 4; i < len; i++) {
  92. b <<= 8;
  93. b |= msg[i];
  94. }
  95. } else {
  96. a = b = c = d = pad;
  97. for (i = 0; i < len; i++) {
  98. a <<= 8;
  99. a |= msg[i];
  100. }
  101. }
  102. TEACORE(FULLROUNDS);
  103. /* return 0;*/
  104. return h0 ^ h1;
  105. }
  106. /*
  107. * What follows in this file is copyright 2000 by Hans Reiser, and the
  108. * licensing of what follows is governed by reiserfs/README
  109. */
  110. u32 yura_hash(const signed char *msg, int len)
  111. {
  112. int j, pow;
  113. u32 a, c;
  114. int i;
  115. for (pow = 1, i = 1; i < len; i++)
  116. pow = pow * 10;
  117. if (len == 1)
  118. a = msg[0] - 48;
  119. else
  120. a = (msg[0] - 48) * pow;
  121. for (i = 1; i < len; i++) {
  122. c = msg[i] - 48;
  123. for (pow = 1, j = i; j < len - 1; j++)
  124. pow = pow * 10;
  125. a = a + c * pow;
  126. }
  127. for (; i < 40; i++) {
  128. c = '0' - 48;
  129. for (pow = 1, j = i; j < len - 1; j++)
  130. pow = pow * 10;
  131. a = a + c * pow;
  132. }
  133. for (; i < 256; i++) {
  134. c = i;
  135. for (pow = 1, j = i; j < len - 1; j++)
  136. pow = pow * 10;
  137. a = a + c * pow;
  138. }
  139. a = a << 7;
  140. return a;
  141. }
  142. u32 r5_hash(const signed char *msg, int len)
  143. {
  144. u32 a = 0;
  145. while (*msg) {
  146. a += *msg << 4;
  147. a += *msg >> 4;
  148. a *= 11;
  149. msg++;
  150. }
  151. return a;
  152. }