104 lines
3.2 KiB
C
104 lines
3.2 KiB
C
/* $NetBSD: hash.h,v 1.6 2008/04/28 20:24:10 martin Exp $ */
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/*-
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* Copyright (c) 2001 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Luke Mewburn.
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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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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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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#ifdef __HAVE_MACHINE_HASH_H
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#include <machine/hash.h>
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#endif
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#ifndef __HAVE_HASH32_BUF /* not overridden by MD hash */
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#define HASH32_BUF_INIT 5381
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/*
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* uint32_t
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* hash32_buf(const void *bf, size_t len, uint32_t hash)
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* return a 32 bit hash of the binary buffer buf (size len),
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* seeded with an initial hash value of hash (usually HASH32_BUF_INIT).
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*/
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static __inline uint32_t
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hash32_buf(const void *bf, size_t len, uint32_t hash)
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{
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const uint8_t *s = bf;
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while (len-- != 0) /* "nemesi": k=257, r=r*257 */
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hash = hash * 257 + *s++;
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return (hash * 257);
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}
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#endif /* __HAVE_HASH32_BUF */
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#ifndef __HAVE_HASH32_STR /* not overridden by MD hash */
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#define HASH32_STR_INIT 5381
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/*
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* uint32_t
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* hash32_str(const void *bf, uint32_t hash)
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* return a 32 bit hash of NUL terminated ASCII string buf,
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* seeded with an initial hash value of hash (usually HASH32_STR_INIT).
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*/
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static __inline uint32_t
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hash32_str(const void *bf, uint32_t hash)
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{
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const uint8_t *s = bf;
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uint8_t c;
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while ((c = *s++) != 0)
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hash = hash * 33 + c; /* "perl": k=33, r=r+r/32 */
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return (hash + (hash >> 5));
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}
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/*
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* uint32_t
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* hash32_strn(const void *bf, size_t len, uint32_t hash)
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* return a 32 bit hash of NUL terminated ASCII string buf up to
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* a maximum of len bytes,
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* seeded with an initial hash value of hash (usually HASH32_STR_INIT).
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*/
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static __inline uint32_t
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hash32_strn(const void *bf, size_t len, uint32_t hash)
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{
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const uint8_t *s = bf;
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uint8_t c;
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while ((c = *s++) != 0 && len-- != 0)
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hash = hash * 33 + c; /* "perl": k=33, r=r+r/32 */
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return (hash + (hash >> 5));
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}
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#endif /* __HAVE_HASH32_STR */
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#endif /* !_SYS_HASH_H_ */
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