1/*	$NetBSD: hash.h,v 1.8 2014/09/05 05:46:15 matt Exp $	*/
  2
  3/*-
  4 * Copyright (c) 2001 The NetBSD Foundation, Inc.
  5 * All rights reserved.
  6 *
  7 * This code is derived from software contributed to The NetBSD Foundation
  8 * by Luke Mewburn.
  9 *
 10 * Redistribution and use in source and binary forms, with or without
 11 * modification, are permitted provided that the following conditions
 12 * are met:
 13 * 1. Redistributions of source code must retain the above copyright
 14 *    notice, this list of conditions and the following disclaimer.
 15 * 2. Redistributions in binary form must reproduce the above copyright
 16 *    notice, this list of conditions and the following disclaimer in the
 17 *    documentation and/or other materials provided with the distribution.
 18 *
 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 29 * POSSIBILITY OF SUCH DAMAGE.
 30 */
 31
 32#ifndef	_SYS_HASH_H_
 33#define	_SYS_HASH_H_
 34
 35#include <sys/types.h>
 36
 37#ifdef __HAVE_MACHINE_HASH_H
 38#include <machine/hash.h>
 39#endif
 40
 41#ifndef __HAVE_HASH32_BUF			/* not overridden by MD hash */
 42
 43#define	HASH32_BUF_INIT	5381
 44
 45/*
 46 * uint32_t
 47 * hash32_buf(const void *bf, size_t len, uint32_t hash)
 48 *	return a 32 bit hash of the binary buffer buf (size len),
 49 *	seeded with an initial hash value of hash (usually HASH32_BUF_INIT).
 50 */
 51static __inline uint32_t
 52hash32_buf(const void *bf, size_t len, uint32_t hash)
 53{
 54	const uint8_t *s = (const uint8_t *)bf;
 55
 56	while (len-- != 0)			/* "nemesi": k=257, r=r*257 */
 57		hash = hash * 257 + *s++;
 58	return (hash * 257);
 59}
 60#endif	/* __HAVE_HASH32_BUF */
 61
 62
 63#ifndef __HAVE_HASH32_STR			/* not overridden by MD hash */
 64
 65#define	HASH32_STR_INIT	5381
 66/*
 67 * uint32_t
 68 * hash32_str(const void *bf, uint32_t hash)
 69 *	return a 32 bit hash of NUL terminated ASCII string buf,
 70 *	seeded with an initial hash value of hash (usually HASH32_STR_INIT).
 71 */
 72static __inline uint32_t
 73hash32_str(const void *bf, uint32_t hash)
 74{
 75	const uint8_t *s = (const uint8_t *)bf;
 76	uint8_t	c;
 77
 78	while ((c = *s++) != 0)
 79		hash = hash * 33 + c;		/* "perl": k=33, r=r+r/32 */
 80	return (hash + (hash >> 5));
 81}
 82
 83/*
 84 * uint32_t
 85 * hash32_strn(const void *bf, size_t len, uint32_t hash)
 86 *	return a 32 bit hash of NUL terminated ASCII string buf up to
 87 *	a maximum of len bytes,
 88 *	seeded with an initial hash value of hash (usually HASH32_STR_INIT).
 89 */
 90static __inline uint32_t
 91hash32_strn(const void *bf, size_t len, uint32_t hash)
 92{
 93	const uint8_t *s = (const uint8_t *)bf;
 94	uint8_t	c;
 95
 96	while ((c = *s++) != 0 && len-- != 0)
 97		hash = hash * 33 + c;		/* "perl": k=33, r=r+r/32 */
 98	return (hash + (hash >> 5));
 99}
100#endif	/* __HAVE_HASH32_STR */
101
102__BEGIN_DECLS
103uint32_t	murmurhash2(const void *, size_t, uint32_t);
104__END_DECLS
105
106#endif	/* !_SYS_HASH_H_ */