1/*****************************************************************************/
2/* */
3/* hashfunc.c */
4/* */
5/* Hash functions */
6/* */
7/* */
8/* */
9/* (C) 1998-2011, Ullrich von Bassewitz */
10/* Roemerstrasse 52 */
11/* D-70794 Filderstadt */
12/* EMail: uz@cc65.org */
13/* */
14/* */
15/* This software is provided 'as-is', without any expressed or implied */
16/* warranty. In no event will the authors be held liable for any damages */
17/* arising from the use of this software. */
18/* */
19/* Permission is granted to anyone to use this software for any purpose, */
20/* including commercial applications, and to alter it and redistribute it */
21/* freely, subject to the following restrictions: */
22/* */
23/* 1. The origin of this software must not be misrepresented; you must not */
24/* claim that you wrote the original software. If you use this software */
25/* in a product, an acknowledgment in the product documentation would be */
26/* appreciated but is not required. */
27/* 2. Altered source versions must be plainly marked as such, and must not */
28/* be misrepresented as being the original software. */
29/* 3. This notice may not be removed or altered from any source */
30/* distribution. */
31/* */
32/*****************************************************************************/
33
34
35
36/* common */
37#include "hashfunc.h"
38
39
40
41/*****************************************************************************/
42/* Code */
43/*****************************************************************************/
44
45
46
47unsigned HashInt (unsigned V)
48/* Return a hash value for the given integer. The function uses Robert
49** Jenkins' 32 bit integer hash function taken from
50** http://www.concentric.net/~ttwang/tech/inthash.htm
51** For 16 bit integers, the function may be suboptimal.
52*/
53{
54 V = (V + 0x7ed55d16) + (V << 12);
55 V = (V ^ 0xc761c23c) ^ (V >> 19);
56 V = (V + 0x165667b1) + (V << 5);
57 V = (V + 0xd3a2646c) ^ (V << 9);
58 V = (V + 0xfd7046c5) + (V << 3);
59 V = (V ^ 0xb55a4f09) ^ (V >> 16);
60 return V;
61}
62
63
64
65unsigned HashStr (const char* S)
66/* Return a hash value for the given string */
67{
68 unsigned L, H;
69
70 /* Do the hash */
71 H = L = 0;
72 while (*S) {
73 H = ((H << 3) ^ ((unsigned char) *S++)) + L++;
74 }
75 return H;
76}
77
78
79
80unsigned HashBuf (const StrBuf* S)
81/* Return a hash value for the given string buffer */
82{
83 unsigned I, L, H;
84
85 /* Do the hash */
86 H = L = 0;
87 for (I = 0; I < SB_GetLen (S); ++I) {
88 H = ((H << 3) ^ ((unsigned char) SB_AtUnchecked (S, I))) + L++;
89 }
90 return H;
91}
92