1 /* $NetBSD: hash.h,v 1.1 2001/12/05 06:51:55 lukem Exp $ */ 2 3 /*- 4 * Copyright (c) 2001 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Luke Mewburn. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 #ifndef _SYS_HASH_H_ 40 #define _SYS_HASH_H_ 41 42 #include <sys/types.h> 43 #ifdef __HAVE_MACHINE_HASH_H 44 #include <machine/hash.h> 45 #endif 46 47 48 #ifndef __HAVE_HASH32_BUF /* not overridden by MD hash */ 49 50 #define HASH32_BUF_INIT 5381 51 52 /* 53 * uint32_t 54 * hash32_buf(const void *buf, size_t len, uint32_t hash) 55 * return a 32 bit hash of the binary buffer buf (size len), 56 * seeded with an initial hash value of hash (usually HASH32_BUF_INIT). 57 */ 58 static __inline uint32_t 59 hash32_buf(const void *buf, size_t len, uint32_t hash) 60 { 61 const uint8_t *s = buf; 62 63 while (len-- != 0) /* "nemesi": k=257, r=r*257 */ 64 hash = hash * 257 + *s++; 65 return (hash * 257); 66 } 67 #endif /* __HAVE_HASH32_BUF */ 68 69 70 #ifndef __HAVE_HASH32_STR /* not overridden by MD hash */ 71 72 #define HASH32_STR_INIT 5381 73 /* 74 * uint32_t 75 * hash32_str(const void *buf, uint32_t hash) 76 * return a 32 bit hash of NUL terminated ASCII string buf, 77 * seeded with an initial hash value of hash (usually HASH32_STR_INIT). 78 */ 79 static __inline uint32_t 80 hash32_str(const void *buf, uint32_t hash) 81 { 82 const uint8_t *s = buf; 83 uint8_t c; 84 85 while ((c = *s++) != 0) 86 hash = hash * 33 + c; /* "perl": k=33, r=r+r/32 */ 87 return (hash + (hash >> 5)); 88 } 89 90 /* 91 * uint32_t 92 * hash32_strn(const void *buf, size_t len, uint32_t hash) 93 * return a 32 bit hash of NUL terminated ASCII string buf up to 94 * a maximum of len bytes, 95 * seeded with an initial hash value of hash (usually HASH32_STR_INIT). 96 */ 97 static __inline uint32_t 98 hash32_strn(const void *buf, size_t len, uint32_t hash) 99 { 100 const uint8_t *s = buf; 101 uint8_t c; 102 103 while ((c = *s++) != 0 && len-- != 0) 104 hash = hash * 33 + c; /* "perl": k=33, r=r+r/32 */ 105 return (hash + (hash >> 5)); 106 } 107 #endif /* __HAVE_HASH32_STR */ 108 109 110 #endif /* !_SYS_HASH_H_ */ 111