Index: openbsd-compat/hash.h =================================================================== RCS file: openbsd-compat/hash.h diff -N openbsd-compat/hash.h --- /dev/null 1 Jan 1970 00:00:00 -0000 +++ openbsd-compat/hash.h 30 Jun 2009 05:48:11 -0000 1.1 @@ -0,0 +1,127 @@ +/* $OpenBSD: hash.h,v 1.4 2004/05/25 18:37:23 jmc Exp $ */ + +/* + * 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. + */ + +#ifndef _SYS_HASH_H_ +#define _SYS_HASH_H_ +#include + +/* + * Note: SMALL_KERNEL might be used to shrink these, right now I + * do not see the point, as my kernel did not grow appreciably when + * I switched to these from other inline code. This may have to be + * revisited when/if these functions become more prevalent in the + * kernel. + */ + +/* 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, char **ep, uint32_t hash) +{ + const unsigned char *p = buf; + + while (*p && (*p != end)) + hash = HASHSTEP(hash, *p++); + + if (ep) + *ep = (char *)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, char **ep, uint32_t hash) +{ + const unsigned char *p = buf; + + while (*p && (*p != end) && len--) + hash = HASHSTEP(hash, *p++); + + if (ep) + *ep = (char *)p; + + return hash; +} +#endif /* !_SYS_HASH_H_ */