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/*-
* Copyright (c) 2001 Tobias Weingartner
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $OpenBSD: hash.h,v 1.4 2004/05/25 18:37:23 jmc Exp $
* $FreeBSD$
*/
#ifndef _SYS_HASH_H_
#define _SYS_HASH_H_
#include <sys/types.h>
/* Convenience */
#ifndef HASHINIT
#define HASHINIT 5381
#define HASHSTEP(x,c) (((x << 5) + x) + (c))
#endif
/*
* Return a 32-bit hash of the given buffer. The init
* value should be 0, or the previous hash value to extend
* the previous hash.
*/
static __inline uint32_t
hash32_buf(const void *buf, size_t len, uint32_t hash)
{
const unsigned char *p = buf;
while (len--)
hash = HASHSTEP(hash, *p++);
return hash;
}
/*
* Return a 32-bit hash of the given string.
*/
static __inline uint32_t
hash32_str(const void *buf, uint32_t hash)
{
const unsigned char *p = buf;
while (*p)
hash = HASHSTEP(hash, *p++);
return hash;
}
/*
* Return a 32-bit hash of the given string, limited by N.
*/
static __inline uint32_t
hash32_strn(const void *buf, size_t len, uint32_t hash)
{
const unsigned char *p = buf;
while (*p && len--)
hash = HASHSTEP(hash, *p++);
return hash;
}
/*
* Return a 32-bit hash of the given string terminated by C,
* (as well as 0). This is mainly here as a helper for the
* namei() hashing of path name parts.
*/
static __inline uint32_t
hash32_stre(const void *buf, int end, const char **ep, uint32_t hash)
{
const unsigned char *p = buf;
while (*p && (*p != end))
hash = HASHSTEP(hash, *p++);
if (ep)
*ep = p;
return hash;
}
/*
* Return a 32-bit hash of the given string, limited by N,
* and terminated by C (as well as 0). This is mainly here
* as a helper for the namei() hashing of path name parts.
*/
static __inline uint32_t
hash32_strne(const void *buf, size_t len, int end, const char **ep,
uint32_t hash)
{
const unsigned char *p = buf;
while (*p && (*p != end) && len--)
hash = HASHSTEP(hash, *p++);
if (ep)
*ep = p;
return hash;
}
#endif /* !_SYS_HASH_H_ */
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