Annotation of libaitcrc/src/hash.c, revision 1.1.2.3
1.1.2.1 misho 1: /*************************************************************************
2: * (C) 2009 AITNET ltd - Sofia/Bulgaria - <misho@aitbg.com>
3: * by Michael Pounov <misho@openbsd-bg.org>
4: *
5: * $Author: misho $
1.1.2.3 ! misho 6: * $Id: hash.c,v 1.1.2.2 2010/09/28 08:40:53 misho Exp $
1.1.2.1 misho 7: *
1.1.2.3 ! misho 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: */
1.1.2.1 misho 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: }
1.1.2.2 misho 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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