1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2001 Tobias Weingartner 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 * 27 * $OpenBSD: hash.h,v 1.4 2004/05/25 18:37:23 jmc Exp $ 28 * $FreeBSD$ 29 */ 30 31 #ifndef _SYS_HASH_H_ 32 #define _SYS_HASH_H_ 33 #include <sys/types.h> 34 35 /* Convenience */ 36 #ifndef HASHINIT 37 #define HASHINIT 5381 38 #define HASHSTEP(x,c) (((x << 5) + x) + (c)) 39 #endif 40 41 /* 42 * Return a 32-bit hash of the given buffer. The init 43 * value should be 0, or the previous hash value to extend 44 * the previous hash. 45 */ 46 static __inline uint32_t 47 hash32_buf(const void *buf, size_t len, uint32_t hash) 48 { 49 const unsigned char *p = buf; 50 51 while (len--) 52 hash = HASHSTEP(hash, *p++); 53 54 return hash; 55 } 56 57 /* 58 * Return a 32-bit hash of the given string. 59 */ 60 static __inline uint32_t 61 hash32_str(const void *buf, uint32_t hash) 62 { 63 const unsigned char *p = buf; 64 65 while (*p) 66 hash = HASHSTEP(hash, *p++); 67 68 return hash; 69 } 70 71 /* 72 * Return a 32-bit hash of the given string, limited by N. 73 */ 74 static __inline uint32_t 75 hash32_strn(const void *buf, size_t len, uint32_t hash) 76 { 77 const unsigned char *p = buf; 78 79 while (*p && len--) 80 hash = HASHSTEP(hash, *p++); 81 82 return hash; 83 } 84 85 /* 86 * Return a 32-bit hash of the given string terminated by C, 87 * (as well as 0). This is mainly here as a helper for the 88 * namei() hashing of path name parts. 89 */ 90 static __inline uint32_t 91 hash32_stre(const void *buf, int end, const char **ep, uint32_t hash) 92 { 93 const unsigned char *p = buf; 94 95 while (*p && (*p != end)) 96 hash = HASHSTEP(hash, *p++); 97 98 if (ep) 99 *ep = p; 100 101 return hash; 102 } 103 104 /* 105 * Return a 32-bit hash of the given string, limited by N, 106 * and terminated by C (as well as 0). This is mainly here 107 * as a helper for the namei() hashing of path name parts. 108 */ 109 static __inline uint32_t 110 hash32_strne(const void *buf, size_t len, int end, const char **ep, 111 uint32_t hash) 112 { 113 const unsigned char *p = buf; 114 115 while (*p && (*p != end) && len--) 116 hash = HASHSTEP(hash, *p++); 117 118 if (ep) 119 *ep = p; 120 121 return hash; 122 } 123 124 #ifdef _KERNEL 125 /* 126 * Hashing function from Bob Jenkins. Implementation in libkern/jenkins_hash.c. 127 */ 128 uint32_t jenkins_hash(const void *, size_t, uint32_t); 129 uint32_t jenkins_hash32(const uint32_t *, size_t, uint32_t); 130 131 uint32_t murmur3_32_hash(const void *, size_t, uint32_t); 132 uint32_t murmur3_32_hash32(const uint32_t *, size_t, uint32_t); 133 134 #endif /* _KERNEL */ 135 136 #endif /* !_SYS_HASH_H_ */ 137