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 */
51 static __inline uint32_t
hash32_buf(const void * bf,size_t len,uint32_t hash)52 hash32_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 */
72 static __inline uint32_t
hash32_str(const void * bf,uint32_t hash)73 hash32_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 */
90 static __inline uint32_t
hash32_strn(const void * bf,size_t len,uint32_t hash)91 hash32_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
103 uint32_t murmurhash2(const void *, size_t, uint32_t);
104 __END_DECLS
105
106 #endif /* !_SYS_HASH_H_ */
107