xref: /netbsd-src/lib/libintl/strhash.c (revision 23c8222edbfb0f0932d88a8351d3a0cf817dfb9e)
1 /*	$NetBSD: strhash.c,v 1.1 2004/09/23 16:44:26 tshiozak Exp $	*/
2 
3 /*-
4  * Copyright (c)2003, 2004 Citrus Project,
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 #if defined(LIBC_SCCS) && !defined(lint)
31 __RCSID("$NetBSD: strhash.c,v 1.1 2004/09/23 16:44:26 tshiozak Exp $");
32 #endif /* LIBC_SCCS and not lint */
33 
34 #include <sys/param.h>
35 #include <sys/types.h>
36 #include <assert.h>
37 #include <stdio.h>
38 #include <string.h>
39 
40 #include "libintl_local.h"
41 
42 /*
43  * string hash function by P.J.Weinberger.
44  * this implementation is derived from src/lib/libc/citrus/citrus_db_hash.c.
45  */
46 u_int32_t
47 /*ARGSUSED*/
48 __intl_string_hash(const char *str)
49 {
50 	const u_int8_t *p;
51 	u_int32_t hash = 0, tmp;
52 
53 	for (p = (const u_int8_t *)str; *p; p++) {
54 		hash <<= 4;
55 		hash += *p;
56 		tmp = hash & 0xF0000000;
57 		if (tmp != 0) {
58 			hash ^= tmp;
59 			hash ^= tmp >> 24;
60 		}
61 	}
62 	return hash;
63 }
64