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_ */