135 lines
3.5 KiB
C
135 lines
3.5 KiB
C
/*-
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* Copyright (c) 2001 Tobias Weingartner
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $OpenBSD: hash.h,v 1.4 2004/05/25 18:37:23 jmc Exp $
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* $FreeBSD$
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*/
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#ifndef _SYS_HASH_H_
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#define _SYS_HASH_H_
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#include <sys/types.h>
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/* Convenience */
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#ifndef HASHINIT
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#define HASHINIT 5381
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#define HASHSTEP(x,c) (((x << 5) + x) + (c))
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#endif
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/*
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* Return a 32-bit hash of the given buffer. The init
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* value should be 0, or the previous hash value to extend
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* the previous hash.
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*/
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static __inline uint32_t
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hash32_buf(const void *buf, size_t len, uint32_t hash)
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{
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const unsigned char *p = buf;
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while (len--)
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hash = HASHSTEP(hash, *p++);
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return hash;
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}
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/*
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* Return a 32-bit hash of the given string.
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*/
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static __inline uint32_t
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hash32_str(const void *buf, uint32_t hash)
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{
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const unsigned char *p = buf;
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while (*p)
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hash = HASHSTEP(hash, *p++);
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return hash;
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}
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/*
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* Return a 32-bit hash of the given string, limited by N.
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*/
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static __inline uint32_t
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hash32_strn(const void *buf, size_t len, uint32_t hash)
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{
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const unsigned char *p = buf;
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while (*p && len--)
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hash = HASHSTEP(hash, *p++);
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return hash;
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}
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/*
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* Return a 32-bit hash of the given string terminated by C,
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* (as well as 0). This is mainly here as a helper for the
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* namei() hashing of path name parts.
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*/
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static __inline uint32_t
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hash32_stre(const void *buf, int end, const char **ep, uint32_t hash)
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{
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const unsigned char *p = buf;
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while (*p && (*p != end))
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hash = HASHSTEP(hash, *p++);
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if (ep)
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*ep = p;
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return hash;
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}
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/*
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* Return a 32-bit hash of the given string, limited by N,
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* and terminated by C (as well as 0). This is mainly here
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* as a helper for the namei() hashing of path name parts.
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*/
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static __inline uint32_t
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hash32_strne(const void *buf, size_t len, int end, const char **ep,
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uint32_t hash)
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{
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const unsigned char *p = buf;
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while (*p && (*p != end) && len--)
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hash = HASHSTEP(hash, *p++);
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if (ep)
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*ep = p;
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return hash;
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}
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#ifdef _KERNEL
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/*
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* Hashing function from Bob Jenkins. Implementation in libkern/jenkins_hash.c.
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*/
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uint32_t jenkins_hash(const void *, size_t, uint32_t);
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uint32_t jenkins_hash32(const uint32_t *, size_t, uint32_t);
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uint32_t murmur3_32_hash(const void *, size_t, uint32_t);
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uint32_t murmur3_32_hash32(const uint32_t *, size_t, uint32_t);
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#endif /* _KERNEL */
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#endif /* !_SYS_HASH_H_ */
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