| 1 | /* $NetBSD: hash.h,v 1.8 2014/09/05 05:46:15 matt 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 | * |
| 19 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
| 20 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
| 21 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| 22 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
| 23 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| 24 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| 25 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 26 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| 27 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 28 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| 29 | * POSSIBILITY OF SUCH DAMAGE. |
| 30 | */ |
| 31 | |
| 32 | #ifndef _SYS_HASH_H_ |
| 33 | #define _SYS_HASH_H_ |
| 34 | |
| 35 | #include <sys/types.h> |
| 36 | |
| 37 | #ifdef __HAVE_MACHINE_HASH_H |
| 38 | #include <machine/hash.h> |
| 39 | #endif |
| 40 | |
| 41 | #ifndef __HAVE_HASH32_BUF /* not overridden by MD hash */ |
| 42 | |
| 43 | #define HASH32_BUF_INIT 5381 |
| 44 | |
| 45 | /* |
| 46 | * uint32_t |
| 47 | * hash32_buf(const void *bf, size_t len, uint32_t hash) |
| 48 | * return a 32 bit hash of the binary buffer buf (size len), |
| 49 | * seeded with an initial hash value of hash (usually HASH32_BUF_INIT). |
| 50 | */ |
| 51 | static __inline uint32_t |
| 52 | hash32_buf(const void *bf, size_t len, uint32_t hash) |
| 53 | { |
| 54 | const uint8_t *s = (const uint8_t *)bf; |
| 55 | |
| 56 | while (len-- != 0) /* "nemesi": k=257, r=r*257 */ |
| 57 | hash = hash * 257 + *s++; |
| 58 | return (hash * 257); |
| 59 | } |
| 60 | #endif /* __HAVE_HASH32_BUF */ |
| 61 | |
| 62 | |
| 63 | #ifndef __HAVE_HASH32_STR /* not overridden by MD hash */ |
| 64 | |
| 65 | #define HASH32_STR_INIT 5381 |
| 66 | /* |
| 67 | * uint32_t |
| 68 | * hash32_str(const void *bf, uint32_t hash) |
| 69 | * return a 32 bit hash of NUL terminated ASCII string buf, |
| 70 | * seeded with an initial hash value of hash (usually HASH32_STR_INIT). |
| 71 | */ |
| 72 | static __inline uint32_t |
| 73 | hash32_str(const void *bf, uint32_t hash) |
| 74 | { |
| 75 | const uint8_t *s = (const uint8_t *)bf; |
| 76 | uint8_t c; |
| 77 | |
| 78 | while ((c = *s++) != 0) |
| 79 | hash = hash * 33 + c; /* "perl": k=33, r=r+r/32 */ |
| 80 | return (hash + (hash >> 5)); |
| 81 | } |
| 82 | |
| 83 | /* |
| 84 | * uint32_t |
| 85 | * hash32_strn(const void *bf, size_t len, uint32_t hash) |
| 86 | * return a 32 bit hash of NUL terminated ASCII string buf up to |
| 87 | * a maximum of len bytes, |
| 88 | * seeded with an initial hash value of hash (usually HASH32_STR_INIT). |
| 89 | */ |
| 90 | static __inline uint32_t |
| 91 | hash32_strn(const void *bf, size_t len, uint32_t hash) |
| 92 | { |
| 93 | const uint8_t *s = (const uint8_t *)bf; |
| 94 | uint8_t c; |
| 95 | |
| 96 | while ((c = *s++) != 0 && len-- != 0) |
| 97 | hash = hash * 33 + c; /* "perl": k=33, r=r+r/32 */ |
| 98 | return (hash + (hash >> 5)); |
| 99 | } |
| 100 | #endif /* __HAVE_HASH32_STR */ |
| 101 | |
| 102 | __BEGIN_DECLS |
| 103 | uint32_t murmurhash2(const void *, size_t, uint32_t); |
| 104 | __END_DECLS |
| 105 | |
| 106 | #endif /* !_SYS_HASH_H_ */ |
| 107 | |