NetBSD/lib/libintl/strhash.c

/*	$NetBSD: strhash.c,v 1.2 2005/04/27 09:50:26 yamt Exp $	*/

/*-
 * Copyright (c)2003, 2004 Citrus Project,
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: strhash.c,v 1.2 2005/04/27 09:50:26 yamt Exp $");
#endif /* LIBC_SCCS and not lint */

#include <sys/param.h>
#include <sys/types.h>

#include "libintl_local.h"

/*
 * string hash function by P.J.Weinberger.
 * this implementation is derived from src/lib/libc/citrus/citrus_db_hash.c.
 */
u_int32_t
/*ARGSUSED*/
__intl_string_hash(const char *str)
{
	const u_int8_t *p;
	u_int32_t hash = 0, tmp;

	for (p = (const u_int8_t *)str; *p; p++) {
		hash <<= 4;
		hash += *p;
		tmp = hash & 0xF0000000;
		if (tmp != 0) {
			hash ^= tmp;
			hash ^= tmp >> 24;
		}
	}
	return hash;
}