1/*-
  2 * SPDX-License-Identifier: BSD-2-Clause
  3 *
  4 * Copyright (c) 2001 Tobias Weingartner
  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 ``AS IS'' AND ANY EXPRESS OR
 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 26 *
 27 * $OpenBSD: hash.h,v 1.4 2004/05/25 18:37:23 jmc Exp $
 28 */
 29
 30#ifndef _SYS_HASH_H_
 31#define	_SYS_HASH_H_
 32#include <sys/types.h>
 33
 34/* Convenience */
 35#ifndef	HASHINIT
 36#define	HASHINIT	5381
 37#define	HASHSTEP(x,c)	(((x << 5) + x) + (c))
 38#endif
 39
 40/*
 41 * Return a 32-bit hash of the given buffer.  The init
 42 * value should be 0, or the previous hash value to extend
 43 * the previous hash.
 44 */
 45static __inline uint32_t
 46hash32_buf(const void *buf, size_t len, uint32_t hash)
 47{
 48	const unsigned char *p = buf;
 49
 50	while (len--)
 51		hash = HASHSTEP(hash, *p++);
 52
 53	return hash;
 54}
 55
 56/*
 57 * Return a 32-bit hash of the given string.
 58 */
 59static __inline uint32_t
 60hash32_str(const void *buf, uint32_t hash)
 61{
 62	const unsigned char *p = buf;
 63
 64	while (*p)
 65		hash = HASHSTEP(hash, *p++);
 66
 67	return hash;
 68}
 69
 70/*
 71 * Return a 32-bit hash of the given string, limited by N.
 72 */
 73static __inline uint32_t
 74hash32_strn(const void *buf, size_t len, uint32_t hash)
 75{
 76	const unsigned char *p = buf;
 77
 78	while (*p && len--)
 79		hash = HASHSTEP(hash, *p++);
 80
 81	return hash;
 82}
 83
 84/*
 85 * Return a 32-bit hash of the given string terminated by C,
 86 * (as well as 0).  This is mainly here as a helper for the
 87 * namei() hashing of path name parts.
 88 */
 89static __inline uint32_t
 90hash32_stre(const void *buf, int end, const char **ep, uint32_t hash)
 91{
 92	const unsigned char *p = buf;
 93
 94	while (*p && (*p != end))
 95		hash = HASHSTEP(hash, *p++);
 96
 97	if (ep)
 98		*ep = p;
 99
100	return hash;
101}
102
103/*
104 * Return a 32-bit hash of the given string, limited by N,
105 * and terminated by C (as well as 0).  This is mainly here
106 * as a helper for the namei() hashing of path name parts.
107 */
108static __inline uint32_t
109hash32_strne(const void *buf, size_t len, int end, const char **ep,
110    uint32_t hash)
111{
112	const unsigned char *p = buf;
113
114	while (*p && (*p != end) && len--)
115		hash = HASHSTEP(hash, *p++);
116
117	if (ep)
118		*ep = p;
119
120	return hash;
121}
122
123#ifdef _KERNEL
124/*
125 * Hashing function from Bob Jenkins. Implementation in libkern/jenkins_hash.c.
126 */
127uint32_t jenkins_hash(const void *, size_t, uint32_t);
128uint32_t jenkins_hash32(const uint32_t *, size_t, uint32_t);
129
130uint32_t murmur3_32_hash(const void *, size_t, uint32_t);
131uint32_t murmur3_32_hash32(const uint32_t *, size_t, uint32_t);
132
133#endif /* _KERNEL */
134
135#endif /* !_SYS_HASH_H_ */