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 */
45 static __inline uint32_t
hash32_buf(const void * buf,size_t len,uint32_t hash)46 hash32_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 */
59 static __inline uint32_t
hash32_str(const void * buf,uint32_t hash)60 hash32_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 */
73 static __inline uint32_t
hash32_strn(const void * buf,size_t len,uint32_t hash)74 hash32_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 */
89 static __inline uint32_t
hash32_stre(const void * buf,int end,const char ** ep,uint32_t hash)90 hash32_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 */
108 static __inline uint32_t
hash32_strne(const void * buf,size_t len,int end,const char ** ep,uint32_t hash)109 hash32_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 struct hashalloc_args {
125 u_int version; /* for extendability, now 0 */
126 int error; /* out: error on failure */
127 size_t size; /* in: wanted, out: allocated */
128 size_t hdrsize; /* size of bucket header, 0 = auto */
129 enum {
130 HASH_TYPE_POWER2 = 0,
131 HASH_TYPE_PRIME,
132 } type;
133 enum {
134 HASH_HEAD_LIST = 0,
135 HASH_HEAD_CK_LIST,
136 HASH_HEAD_SLIST,
137 HASH_HEAD_CK_SLIST,
138 HASH_HEAD_STAILQ,
139 HASH_HEAD_CK_STAILQ,
140 HASH_HEAD_TAILQ,
141 } head;
142 enum {
143 HASH_LOCK_NONE = 0,
144 HASH_LOCK_MTX,
145 HASH_LOCK_RWLOCK,
146 HASH_LOCK_SX,
147 HASH_LOCK_RMLOCK,
148 HASH_LOCK_RMSLOCK,
149 } lock;
150 int mflags; /* malloc(9) flags */
151 int lopts; /* lock opts */
152 struct malloc_type *mtype; /* malloc(9) type */
153 const char *lname; /* lock name */
154 int (*ctor)(void *); /* bucket constructor */
155 void (*dtor)(void *); /* bucket destructor */
156 };
157
158 void *hashalloc(struct hashalloc_args *);
159 void hashfree(void *, struct hashalloc_args *);
160
161 /*
162 * Hashing function from Bob Jenkins. Implementation in libkern/jenkins_hash.c.
163 */
164 uint32_t jenkins_hash(const void *, size_t, uint32_t);
165 uint32_t jenkins_hash32(const uint32_t *, size_t, uint32_t);
166
167 uint32_t murmur3_32_hash(const void *, size_t, uint32_t);
168 uint32_t murmur3_32_hash32(const uint32_t *, size_t, uint32_t);
169
170 #endif /* _KERNEL */
171
172 #endif /* !_SYS_HASH_H_ */
173