1/* $OpenBSD: ohash_interval.c,v 1.3 2006/01/16 15:52:25 espie Exp $ */
2/* ex:ts=8 sw=4:
3 */
4
5/* Copyright (c) 1999, 2004 Marc Espie <espie@openbsd.org>
6 *
7 * Permission to use, copy, modify, and distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
10 *
11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
17 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 */
19#include <sys/cdefs.h>
20__FBSDID("$FreeBSD: releng/10.3/usr.bin/m4/lib/ohash_interval.c 228063 2011-11-28 13:32:39Z bapt $");
21
22#include "ohash_int.h"
23
24uint32_t
25ohash_interval(const char *s, const char **e)
26{
27	uint32_t k;
28
29	if (!*e)
30		*e = s + strlen(s);
31	if (s == *e)
32		k = 0;
33	else
34		k = *s++;
35	while (s != *e)
36		k =  ((k << 2) | (k >> 30)) ^ *s++;
37	return k;
38}
39