| Line | Branch | Exec | Source |
|---|---|---|---|
| 1 | /* | ||
| 2 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. | ||
| 3 | * | ||
| 4 | * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved. | ||
| 5 | * | ||
| 6 | * Redistribution and use in source and binary forms, with or without | ||
| 7 | * modification, are permitted provided that the following conditions are met: | ||
| 8 | * | ||
| 9 | * 1. Redistributions of source code must retain the above copyright | ||
| 10 | * notice, this list of conditions and the following disclaimer. | ||
| 11 | * | ||
| 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 COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" | ||
| 17 | * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | ||
| 18 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | ||
| 19 | * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE | ||
| 20 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | ||
| 21 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | ||
| 22 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | ||
| 23 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | ||
| 24 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | ||
| 25 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | ||
| 26 | * POSSIBILITY OF SUCH DAMAGE. | ||
| 27 | */ | ||
| 28 | |||
| 29 | #include "cx/hash_key.h" | ||
| 30 | #include <string.h> | ||
| 31 | |||
| 32 | 170 | void cx_hash_murmur(CxHashKey *key) { | |
| 33 | 170 | const unsigned char *data = key->data; | |
| 34 |
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170 | if (data == NULL) { |
| 35 | // extension: special value for NULL | ||
| 36 | 3 | key->hash = 1574210520u; | |
| 37 | 3 | return; | |
| 38 | } | ||
| 39 | 167 | size_t len = key->len; | |
| 40 | |||
| 41 | 167 | unsigned m = 0x5bd1e995; | |
| 42 | 167 | unsigned r = 24; | |
| 43 | 167 | unsigned h = 25 ^ (unsigned) len; | |
| 44 | 167 | unsigned i = 0; | |
| 45 |
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578 | while (len >= 4) { |
| 46 | 411 | unsigned k = data[i + 0] & 0xFF; | |
| 47 | 411 | k |= (data[i + 1] & 0xFF) << 8; | |
| 48 | 411 | k |= (data[i + 2] & 0xFF) << 16; | |
| 49 | 411 | k |= (data[i + 3] & 0xFF) << 24; | |
| 50 | |||
| 51 | 411 | k *= m; | |
| 52 | 411 | k ^= k >> r; | |
| 53 | 411 | k *= m; | |
| 54 | |||
| 55 | 411 | h *= m; | |
| 56 | 411 | h ^= k; | |
| 57 | |||
| 58 | 411 | i += 4; | |
| 59 | 411 | len -= 4; | |
| 60 | } | ||
| 61 | |||
| 62 |
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167 | switch (len) { |
| 63 | 7 | case 3: | |
| 64 | 7 | h ^= (data[i + 2] & 0xFF) << 16; | |
| 65 | __attribute__((__fallthrough__)); | ||
| 66 | 22 | case 2: | |
| 67 | 22 | h ^= (data[i + 1] & 0xFF) << 8; | |
| 68 | __attribute__((__fallthrough__)); | ||
| 69 | 133 | case 1: | |
| 70 | 133 | h ^= (data[i + 0] & 0xFF); | |
| 71 | 133 | h *= m; | |
| 72 | __attribute__((__fallthrough__)); | ||
| 73 | 167 | default: // do nothing | |
| 74 | ; | ||
| 75 | } | ||
| 76 | |||
| 77 | 167 | h ^= h >> 13; | |
| 78 | 167 | h *= m; | |
| 79 | 167 | h ^= h >> 15; | |
| 80 | |||
| 81 | 167 | key->hash = h; | |
| 82 | } | ||
| 83 | |||
| 84 | 114 | CxHashKey cx_hash_key_str(const char *str) { | |
| 85 | CxHashKey key; | ||
| 86 | 114 | key.data = str; | |
| 87 |
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114 | key.len = str == NULL ? 0 : strlen(str); |
| 88 | 114 | cx_hash_murmur(&key); | |
| 89 | 114 | return key; | |
| 90 | } | ||
| 91 | |||
| 92 | 3 | CxHashKey cx_hash_key_bytes( | |
| 93 | const unsigned char *bytes, | ||
| 94 | size_t len | ||
| 95 | ) { | ||
| 96 | CxHashKey key; | ||
| 97 | 3 | key.data = bytes; | |
| 98 | 3 | key.len = len; | |
| 99 | 3 | cx_hash_murmur(&key); | |
| 100 | 3 | return key; | |
| 101 | } | ||
| 102 | |||
| 103 | 23 | CxHashKey cx_hash_key( | |
| 104 | const void *obj, | ||
| 105 | size_t len | ||
| 106 | ) { | ||
| 107 | CxHashKey key; | ||
| 108 | 23 | key.data = obj; | |
| 109 | 23 | key.len = len; | |
| 110 | 23 | cx_hash_murmur(&key); | |
| 111 | 23 | return key; | |
| 112 | } | ||
| 113 |