lib/libintl/strhash.c

   1 /*      $NetBSD: strhash.c,v 1.3 2007/09/25 08:19:09 junyoung 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 1.3 2007/09/25 08:19:09 junyoung Exp $");
  32 #endif /* LIBC_SCCS and not lint */
  33
  34 #include <sys/param.h>
  35 #include <sys/types.h>
  36
  37 #include "libintl_local.h"
  38
  39 /*
  40  * string hash function by P.J.Weinberger.
  41  * this implementation is derived from src/lib/libc/citrus/citrus_db_hash.c.
  42  */
  43 uint32_t
  44 /*ARGSUSED*/
  45 __intl_string_hash(const char *str)
  46 {
  47         const uint8_t *p;
  48         uint32_t hash = 0, tmp;
  49
  50         for (p = (const uint8_t *)str; *p; p++) {
  51                 hash <<= 4;
  52                 hash += *p;
  53                 tmp = hash & 0xF0000000;
  54                 if (tmp != 0) {
  55                         hash ^= tmp;
  56                         hash ^= tmp >> 24;
  57                 }
  58         }
  59         return hash;
  60 }