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 /* * Keyed 32-bit hash function using TEA in a Davis-Meyer function * H0 = Key * Hi = E Mi(Hi-1) + Hi-1 * * (see Applied Cryptography, 2nd edition, p448). * * Jeremy Fitzhardinge 1998 * * Jeremy has agreed to the contents of reiserfs/README. -Hans * Yura's function is added (04/07/2000) */ #include #include "reiserfs.h" #include #define DELTA 0x9E3779B9 #define FULLROUNDS 10 /* 32 is overkill, 16 is strong crypto */ #define PARTROUNDS 6 /* 6 gets complete mixing */ /* a, b, c, d - data; h0, h1 - accumulated hash */ #define TEACORE(rounds) \ do { \ u32 sum = 0; \ int n = rounds; \ u32 b0, b1; \ \ b0 = h0; \ b1 = h1; \ \ do \ { \ sum += DELTA; \ b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b); \ b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d); \ } while(--n); \ \ h0 += b0; \ h1 += b1; \ } while(0) u32 keyed_hash(const signed char *msg, int len) { u32 k[] = { 0x9464a485, 0x542e1a94, 0x3e846bff, 0xb75bcfc3 }; u32 h0 = k[0], h1 = k[1]; u32 a, b, c, d; u32 pad; int i; /* assert(len >= 0 && len < 256); */ pad = (u32) len | ((u32) len << 8); pad |= pad << 16; while (len >= 16) { a = (u32) msg[0] | (u32) msg[1] << 8 | (u32) msg[2] << 16 | (u32) msg[3] << 24; b = (u32) msg[4] | (u32) msg[5] << 8 | (u32) msg[6] << 16 | (u32) msg[7] << 24; c = (u32) msg[8] | (u32) msg[9] << 8 | (u32) msg[10] << 16 | (u32) msg[11] << 24; d = (u32) msg[12] | (u32) msg[13] << 8 | (u32) msg[14] << 16 | (u32) msg[15] << 24; TEACORE(PARTROUNDS); len -= 16; msg += 16; } if (len >= 12) { a = (u32) msg[0] | (u32) msg[1] << 8 | (u32) msg[2] << 16 | (u32) msg[3] << 24; b = (u32) msg[4] | (u32) msg[5] << 8 | (u32) msg[6] << 16 | (u32) msg[7] << 24; c = (u32) msg[8] | (u32) msg[9] << 8 | (u32) msg[10] << 16 | (u32) msg[11] << 24; d = pad; for (i = 12; i < len; i++) { d <<= 8; d |= msg[i]; } } else if (len >= 8) { a = (u32) msg[0] | (u32) msg[1] << 8 | (u32) msg[2] << 16 | (u32) msg[3] << 24; b = (u32) msg[4] | (u32) msg[5] << 8 | (u32) msg[6] << 16 | (u32) msg[7] << 24; c = d = pad; for (i = 8; i < len; i++) { c <<= 8; c |= msg[i]; } } else if (len >= 4) { a = (u32) msg[0] | (u32) msg[1] << 8 | (u32) msg[2] << 16 | (u32) msg[3] << 24; b = c = d = pad; for (i = 4; i < len; i++) { b <<= 8; b |= msg[i]; } } else { a = b = c = d = pad; for (i = 0; i < len; i++) { a <<= 8; a |= msg[i]; } } TEACORE(FULLROUNDS); /* return 0;*/ return h0 ^ h1; } /* * What follows in this file is copyright 2000 by Hans Reiser, and the * licensing of what follows is governed by reiserfs/README */ u32 yura_hash(const signed char *msg, int len) { int j, pow; u32 a, c; int i; for (pow = 1, i = 1; i < len; i++) pow = pow * 10; if (len == 1) a = msg[0] - 48; else a = (msg[0] - 48) * pow; for (i = 1; i < len; i++) { c = msg[i] - 48; for (pow = 1, j = i; j < len - 1; j++) pow = pow * 10; a = a + c * pow; } for (; i < 40; i++) { c = '0' - 48; for (pow = 1, j = i; j < len - 1; j++) pow = pow * 10; a = a + c * pow; } for (; i < 256; i++) { c = i; for (pow = 1, j = i; j < len - 1; j++) pow = pow * 10; a = a + c * pow; } a = a << 7; return a; } u32 r5_hash(const signed char *msg, int len) { u32 a = 0; while (*msg) { a += *msg << 4; a += *msg >> 4; a *= 11; msg++; } return a; }