2 * ngIRCd -- The Next Generation IRC Daemon
3 * Copyright (c)2001-2010 Alexander Barton (alex@barton.de)
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 * Please read the file COPYING, README and AUTHORS for more information.
29 static UINT32 jenkins_hash PARAMS((UINT8 *k, UINT32 length, UINT32 initval));
32 * Calculate hash value for a given string.
34 * @param String Input string
35 * @return 32 bit hash value
38 Hash( const char *String )
40 char buffer[LINE_LEN];
42 strlcpy(buffer, String, sizeof(buffer));
43 return jenkins_hash((UINT8 *)ngt_LowerStr(buffer),
44 (UINT32)strlen(buffer), 42);
48 * This hash function originates from lookup3.c of Bob Jenkins
49 * (URL: <http://burtleburtle.net/bob/c/lookup3.c>):
50 * --------------------------------------------------------------------
51 * lookup3.c, by Bob Jenkins, May 2006, Public Domain.
52 * These are functions for producing 32-bit hashes for hash table lookup.
53 * hashword(), hashlittle(), hashlittle2(), hashbig(), mix(), and final()
54 * are externally useful functions. Routines to test the hash are included
55 * if SELF_TEST is defined. You can use this free for any purpose. It's in
56 * the public domain. It has no warranty.
57 * --------------------------------------------------------------------
58 * Not all of his functions are used here.
61 #define hashsize(n) ((UINT32)1<<(n))
62 #define hashmask(n) (hashsize(n)-1)
63 #define rot(x,k) (((x)<<(k)) | ((x)>>(32-(k))))
67 a -= c; a ^= rot(c, 4); c += b; \
68 b -= a; b ^= rot(a, 6); a += c; \
69 c -= b; c ^= rot(b, 8); b += a; \
70 a -= c; a ^= rot(c,16); c += b; \
71 b -= a; b ^= rot(a,19); a += c; \
72 c -= b; c ^= rot(b, 4); b += a; \
75 #define final(a,b,c) \
77 c ^= b; c -= rot(b,14); \
78 a ^= c; a -= rot(c,11); \
79 b ^= a; b -= rot(a,25); \
80 c ^= b; c -= rot(b,16); \
81 a ^= c; a -= rot(c,4); \
82 b ^= a; b -= rot(a,14); \
83 c ^= b; c -= rot(b,24); \
87 jenkins_hash(UINT8 *k, UINT32 length, UINT32 initval)
90 * length: length of the key
91 * initval: the previous hash, or an arbitrary value
95 /* Set up the internal state */
96 a = b = c = 0xdeadbeef + length + initval;
98 /* handle most of the key */
100 a += (k[0] +((UINT32)k[1]<<8) +((UINT32)k[2]<<16) +((UINT32)k[3]<<24));
101 b += (k[4] +((UINT32)k[5]<<8) +((UINT32)k[6]<<16) +((UINT32)k[7]<<24));
102 c += (k[8] +((UINT32)k[9]<<8) +((UINT32)k[10]<<16)+((UINT32)k[11]<<24));
108 /*-------------------------------- last block: affect all 32 bits of (c) */
109 switch(length) /* all the case statements fall through */
112 case 12: c+=((UINT32)k[11])<<24;
113 case 11: c+=((UINT32)k[10]<<16);
114 case 10: c+=((UINT32)k[9]<<8);
116 case 8 : b+=((UINT32)k[7]<<24);
117 case 7 : b+=((UINT32)k[6]<<16);
118 case 6 : b+=((UINT32)k[5]<<8);
120 case 4 : a+=((UINT32)k[3]<<24);
121 case 3 : a+=((UINT32)k[2]<<16);
122 case 2 : a+=((UINT32)k[1]<<8);