Annotation of libaitcrc/src/hash.c, revision 1.2
1.2 ! misho 1: /*************************************************************************
! 2: * (C) 2009 AITNET ltd - Sofia/Bulgaria - <misho@aitbg.com>
! 3: * by Michael Pounov <misho@openbsd-bg.org>
! 4: *
! 5: * $Author: misho $
! 6: * $Id: hash.c,v 1.1.2.3 2011/04/28 20:27:34 misho Exp $
! 7: *
! 8: **************************************************************************
! 9: The ELWIX and AITNET software is distributed under the following
! 10: terms:
! 11:
! 12: All of the documentation and software included in the ELWIX and AITNET
! 13: Releases is copyrighted by ELWIX - Sofia/Bulgaria <info@elwix.org>
! 14:
! 15: Copyright 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
! 16: by Michael Pounov <misho@elwix.org>. All rights reserved.
! 17:
! 18: Redistribution and use in source and binary forms, with or without
! 19: modification, are permitted provided that the following conditions
! 20: are met:
! 21: 1. Redistributions of source code must retain the above copyright
! 22: notice, this list of conditions and the following disclaimer.
! 23: 2. Redistributions in binary form must reproduce the above copyright
! 24: notice, this list of conditions and the following disclaimer in the
! 25: documentation and/or other materials provided with the distribution.
! 26: 3. All advertising materials mentioning features or use of this software
! 27: must display the following acknowledgement:
! 28: This product includes software developed by Michael Pounov <misho@elwix.org>
! 29: ELWIX - Embedded LightWeight unIX and its contributors.
! 30: 4. Neither the name of AITNET nor the names of its contributors
! 31: may be used to endorse or promote products derived from this software
! 32: without specific prior written permission.
! 33:
! 34: THIS SOFTWARE IS PROVIDED BY AITNET AND CONTRIBUTORS ``AS IS'' AND
! 35: ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
! 36: IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
! 37: ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
! 38: FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
! 39: DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
! 40: OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
! 41: HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
! 42: LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
! 43: OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
! 44: SUCH DAMAGE.
! 45: */
! 46: #include "global.h"
! 47:
! 48:
! 49: /*
! 50: * hash_varchar() Compute index hash by variable length string
! 51: * @csStr = Input data buffer
! 52: * @nStrLen = Length of data buffer
! 53: * @nVer = Version of algorythm; 0 - original, 1 - AITNET variant
! 54: * return: Hash value
! 55: */
! 56: inline u_int
! 57: hash_varchar(const char *csStr, int nStrLen, int nVer)
! 58: {
! 59: register u_int n, hash = 0;
! 60: register int i;
! 61:
! 62: assert(csStr);
! 63:
! 64: for (i = 0; i < nStrLen; i++) {
! 65: n = 2 * hash + csStr[i];
! 66: if (!nVer) {
! 67: if (hash & 0x80000000)
! 68: n ^= 0xC0A0A0D5; // Polynom CRC-32 aviation
! 69: } else {
! 70: if (n & 1) // Misho ;) patch for better avalanche!!!
! 71: n ^= 0xC0A0A0D5; // Polynom CRC-32 aviation
! 72: }
! 73: hash = n;
! 74: }
! 75:
! 76: return hash;
! 77: }
! 78:
! 79: /*
! 80: * hash_bernstein() Compute index hash by Bernstein
! 81: * @csStr = Input data buffer
! 82: * @nStrLen = Length of data buffer
! 83: * @nVer = Version of algorythm; 0 - Bernstein, 1 - DJBX33A variant
! 84: * return: Hash value
! 85: */
! 86: inline u_int
! 87: hash_bernstein(const char *csStr, int nStrLen, int nVer)
! 88: {
! 89: register u_int hash = 5381;
! 90: register int i;
! 91:
! 92: assert(csStr);
! 93:
! 94: for (i = 0; i < nStrLen; i++)
! 95: if (!nVer)
! 96: hash = ((hash << 5) + hash) + csStr[i];
! 97: else
! 98: hash = hash * 33 + csStr[i]; // DJBX33A
! 99:
! 100: return hash;
! 101: }
! 102:
! 103: /*
! 104: * hash_fnv1() Compute index hash by FNV-1
! 105: * @csStr = Input data buffer
! 106: * @nStrLen = Length of data buffer
! 107: * @nVer = Version of algorythm; 0 - FNV-1, 1 - FNV-1a (best avalanche)
! 108: * return: Hash value
! 109: */
! 110: inline u_int
! 111: hash_fnv1(const char *csStr, int nStrLen, int nVer)
! 112: {
! 113: register u_int hash = 0x811c9dc5; // 2166136261
! 114: register int i;
! 115:
! 116: assert(csStr);
! 117:
! 118: for (i = 0; i < nStrLen; i++)
! 119: if (!nVer) { // FNV-1
! 120: hash *= 16777619;
! 121: hash ^= csStr[i];
! 122: } else { // FNV-1a
! 123: hash ^= csStr[i];
! 124: hash *= 16777619;
! 125: }
! 126:
! 127: return hash;
! 128: }
! 129:
! 130: /*
! 131: * hash_jenkins() Compute index hash by Jenkins (one-at-a-time)
! 132: * @csStr = Input data buffer
! 133: * @nStrLen = Length of data buffer
! 134: * return: Hash value
! 135: */
! 136: inline u_int
! 137: hash_jenkins(const char *csStr, int nStrLen)
! 138: {
! 139: register u_int hash = 0;
! 140: register int i;
! 141:
! 142: assert(csStr);
! 143:
! 144: for (i = 0; i < nStrLen; i++) {
! 145: hash += csStr[i];
! 146: hash += (hash << 10);
! 147: hash ^= (hash >> 6);
! 148: }
! 149: hash += (hash << 3);
! 150: hash ^= (hash >> 11);
! 151: hash += (hash << 15);
! 152:
! 153: return hash;
! 154: }
! 155:
! 156: /*
! 157: * hash_reddragon() Compute index hash by Red Dragon
! 158: * @csStr = Input data buffer
! 159: * @nStrLen = Length of data buffer
! 160: * return: Hash value
! 161: */
! 162: inline u_int
! 163: hash_reddragon(const char *csStr, int nStrLen)
! 164: {
! 165: register u_int g, hash;
! 166: register int i;
! 167:
! 168: assert(csStr);
! 169:
! 170: for (hash = 0, i = 0; i < nStrLen; i++) {
! 171: hash = (hash << 4) + csStr[i];
! 172: if ((g = hash & 0xF0000000)) {
! 173: hash ^= g >> 24;
! 174: hash ^= g;
! 175: }
! 176: }
! 177:
! 178: return hash;
! 179: }
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