2 * Copyright (c) 2001 Tobias Weingartner
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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.
25 * $OpenBSD: hash.h,v 1.4 2004/05/25 18:37:23 jmc Exp $
26 * $FreeBSD: src/sys/sys/hash.h,v 1.3 2007/04/09 22:55:14 thompsa Exp $
31 #include <sys/types.h>
36 #define HASHSTEP(x,c) (((x << 5) + x) + (c))
40 * Return a 32-bit hash of the given buffer. The init
41 * value should be 0, or the previous hash value to extend
44 static __inline
uint32_t
45 hash32_buf(const void *buf
, size_t len
, uint32_t hash
)
47 const unsigned char *p
= buf
;
50 hash
= HASHSTEP(hash
, *p
++);
56 * Return a 32-bit hash of the given string.
58 static __inline
uint32_t
59 hash32_str(const void *buf
, uint32_t hash
)
61 const unsigned char *p
= buf
;
64 hash
= HASHSTEP(hash
, *p
++);
70 * Return a 32-bit hash of the given string, limited by N.
72 static __inline
uint32_t
73 hash32_strn(const void *buf
, size_t len
, uint32_t hash
)
75 const unsigned char *p
= buf
;
78 hash
= HASHSTEP(hash
, *p
++);
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.
88 static __inline
uint32_t
89 hash32_stre(const void *buf
, int end
, const char **ep
, uint32_t hash
)
91 const unsigned char *p
= buf
;
93 while (*p
&& (*p
!= end
))
94 hash
= HASHSTEP(hash
, *p
++);
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.
107 static __inline
uint32_t
108 hash32_strne(const void *buf
, size_t len
, int end
, const char **ep
,
111 const unsigned char *p
= buf
;
113 while (*p
&& (*p
!= end
) && len
--)
114 hash
= HASHSTEP(hash
, *p
++);
122 #endif /* !_SYS_HASH_H_ */