1/*-
2 * Copyright (c) 2001 Tobias Weingartner
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 *
25 * $OpenBSD: hash.h,v 1.4 2004/05/25 18:37:23 jmc Exp $
26 * $FreeBSD$
27 */
28
29#ifndef _SYS_HASH_H_
30#define	_SYS_HASH_H_
31#include <sys/types.h>
32
33/* Convenience */
34#ifndef	HASHINIT
35#define	HASHINIT	5381
36#define	HASHSTEP(x,c)	(((x << 5) + x) + (c))
37#endif
38
39/*
40 * Return a 32-bit hash of the given buffer.  The init
41 * value should be 0, or the previous hash value to extend
42 * the previous hash.
43 */
44static __inline uint32_t
45hash32_buf(const void *buf, size_t len, uint32_t hash)
46{
47	const unsigned char *p = buf;
48
49	while (len--)
50		hash = HASHSTEP(hash, *p++);
51
52	return hash;
53}
54
55/*
56 * Return a 32-bit hash of the given string.
57 */
58static __inline uint32_t
59hash32_str(const void *buf, uint32_t hash)
60{
61	const unsigned char *p = buf;
62
63	while (*p)
64		hash = HASHSTEP(hash, *p++);
65
66	return hash;
67}
68
69/*
70 * Return a 32-bit hash of the given string, limited by N.
71 */
72static __inline uint32_t
73hash32_strn(const void *buf, size_t len, uint32_t hash)
74{
75	const unsigned char *p = buf;
76
77	while (*p && len--)
78		hash = HASHSTEP(hash, *p++);
79
80	return hash;
81}
82
83/*
84 * Return a 32-bit hash of the given string terminated by C,
85 * (as well as 0).  This is mainly here as a helper for the
86 * namei() hashing of path name parts.
87 */
88static __inline uint32_t
89hash32_stre(const void *buf, int end, const char **ep, uint32_t hash)
90{
91	const unsigned char *p = buf;
92
93	while (*p && (*p != end))
94		hash = HASHSTEP(hash, *p++);
95
96	if (ep)
97		*ep = p;
98
99	return hash;
100}
101
102/*
103 * Return a 32-bit hash of the given string, limited by N,
104 * and terminated by C (as well as 0).  This is mainly here
105 * as a helper for the namei() hashing of path name parts.
106 */
107static __inline uint32_t
108hash32_strne(const void *buf, size_t len, int end, const char **ep,
109    uint32_t hash)
110{
111	const unsigned char *p = buf;
112
113	while (*p && (*p != end) && len--)
114		hash = HASHSTEP(hash, *p++);
115
116	if (ep)
117		*ep = p;
118
119	return hash;
120}
121
122#ifdef _KERNEL
123/*
124 * Hashing function from Bob Jenkins. Implementation in libkern/jenkins_hash.c.
125 */
126uint32_t jenkins_hash(const void *, size_t, uint32_t);
127uint32_t jenkins_hash32(const uint32_t *, size_t, uint32_t);
128
129uint32_t murmur3_aligned_32(const void *data, size_t len, uint32_t seed);
130
131#endif /* _KERNEL */
132
133#endif /* !_SYS_HASH_H_ */
134