1*b5745d08Sguenther /* $OpenBSD: hash_func.c,v 1.11 2016/05/29 20:47:49 guenther Exp $ */
21b727fc6Smillert
3df930be7Sderaadt /*-
4df930be7Sderaadt * Copyright (c) 1990, 1993
5df930be7Sderaadt * The Regents of the University of California. All rights reserved.
6df930be7Sderaadt *
7df930be7Sderaadt * This code is derived from software contributed to Berkeley by
8df930be7Sderaadt * Margo Seltzer.
9df930be7Sderaadt *
10df930be7Sderaadt * Redistribution and use in source and binary forms, with or without
11df930be7Sderaadt * modification, are permitted provided that the following conditions
12df930be7Sderaadt * are met:
13df930be7Sderaadt * 1. Redistributions of source code must retain the above copyright
14df930be7Sderaadt * notice, this list of conditions and the following disclaimer.
15df930be7Sderaadt * 2. Redistributions in binary form must reproduce the above copyright
16df930be7Sderaadt * notice, this list of conditions and the following disclaimer in the
17df930be7Sderaadt * documentation and/or other materials provided with the distribution.
186580fee3Smillert * 3. Neither the name of the University nor the names of its contributors
19df930be7Sderaadt * may be used to endorse or promote products derived from this software
20df930be7Sderaadt * without specific prior written permission.
21df930be7Sderaadt *
22df930be7Sderaadt * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23df930be7Sderaadt * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24df930be7Sderaadt * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25df930be7Sderaadt * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26df930be7Sderaadt * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27df930be7Sderaadt * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28df930be7Sderaadt * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29df930be7Sderaadt * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30df930be7Sderaadt * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31df930be7Sderaadt * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32df930be7Sderaadt * SUCH DAMAGE.
33df930be7Sderaadt */
34df930be7Sderaadt
35df930be7Sderaadt #include <sys/types.h>
36df930be7Sderaadt
37df930be7Sderaadt #include <db.h>
381b727fc6Smillert
391b727fc6Smillert /* Chris Torek's hash function. */
401b727fc6Smillert u_int32_t
__default_hash(const void * key,size_t len)41*b5745d08Sguenther __default_hash(const void *key, size_t len)
42df930be7Sderaadt {
431b727fc6Smillert u_int32_t h, loop;
441b727fc6Smillert u_int8_t *k;
45df930be7Sderaadt
461b727fc6Smillert #define HASH4a h = (h << 5) - h + *k++;
471b727fc6Smillert #define HASH4b h = (h << 5) + h + *k++;
48df930be7Sderaadt #define HASH4 HASH4b
49df930be7Sderaadt
50df930be7Sderaadt h = 0;
511b727fc6Smillert k = (u_int8_t *)key;
52df930be7Sderaadt if (len > 0) {
53df930be7Sderaadt loop = (len + 8 - 1) >> 3;
54df930be7Sderaadt
55df930be7Sderaadt switch (len & (8 - 1)) {
56df930be7Sderaadt case 0:
571b727fc6Smillert do { /* All fall throughs */
58df930be7Sderaadt HASH4;
59df930be7Sderaadt case 7:
60df930be7Sderaadt HASH4;
61df930be7Sderaadt case 6:
62df930be7Sderaadt HASH4;
63df930be7Sderaadt case 5:
64df930be7Sderaadt HASH4;
65df930be7Sderaadt case 4:
66df930be7Sderaadt HASH4;
67df930be7Sderaadt case 3:
68df930be7Sderaadt HASH4;
69df930be7Sderaadt case 2:
70df930be7Sderaadt HASH4;
71df930be7Sderaadt case 1:
72df930be7Sderaadt HASH4;
73df930be7Sderaadt } while (--loop);
74df930be7Sderaadt }
751b727fc6Smillert
76df930be7Sderaadt }
77df930be7Sderaadt return (h);
78df930be7Sderaadt }
79