1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000 1.2 +++ b/src/hash_key.c Wed Jun 08 21:33:31 2022 +0200 1.3 @@ -0,0 +1,107 @@ 1.4 +/* 1.5 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. 1.6 + * 1.7 + * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved. 1.8 + * 1.9 + * Redistribution and use in source and binary forms, with or without 1.10 + * modification, are permitted provided that the following conditions are met: 1.11 + * 1.12 + * 1. Redistributions of source code must retain the above copyright 1.13 + * notice, this list of conditions and the following disclaimer. 1.14 + * 1.15 + * 2. Redistributions in binary form must reproduce the above copyright 1.16 + * notice, this list of conditions and the following disclaimer in the 1.17 + * documentation and/or other materials provided with the distribution. 1.18 + * 1.19 + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 1.20 + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 1.21 + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 1.22 + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 1.23 + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 1.24 + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 1.25 + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 1.26 + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 1.27 + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 1.28 + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 1.29 + * POSSIBILITY OF SUCH DAMAGE. 1.30 + */ 1.31 + 1.32 +#include "cx/hash_key.h" 1.33 +#include <string.h> 1.34 + 1.35 +void cx_hash_murmur(CxHashKey *key) { 1.36 + size_t len = key->len; 1.37 + unsigned char const *data = key->data.cbytes; 1.38 + 1.39 + unsigned m = 0x5bd1e995; 1.40 + unsigned r = 24; 1.41 + unsigned h = 25 ^ len; 1.42 + unsigned i = 0; 1.43 + while (len >= 4) { 1.44 + unsigned k = data[i + 0] & 0xFF; 1.45 + k |= (data[i + 1] & 0xFF) << 8; 1.46 + k |= (data[i + 2] & 0xFF) << 16; 1.47 + k |= (data[i + 3] & 0xFF) << 24; 1.48 + 1.49 + k *= m; 1.50 + k ^= k >> r; 1.51 + k *= m; 1.52 + 1.53 + h *= m; 1.54 + h ^= k; 1.55 + 1.56 + i += 4; 1.57 + len -= 4; 1.58 + } 1.59 + 1.60 + switch (len) { 1.61 + case 3: 1.62 + h ^= (data[i + 2] & 0xFF) << 16; 1.63 + __attribute__((__fallthrough__)); 1.64 + case 2: 1.65 + h ^= (data[i + 1] & 0xFF) << 8; 1.66 + __attribute__((__fallthrough__)); 1.67 + case 1: 1.68 + h ^= (data[i + 0] & 0xFF); 1.69 + h *= m; 1.70 + __attribute__((__fallthrough__)); 1.71 + default: 1.72 + /* do nothing */; 1.73 + } 1.74 + 1.75 + h ^= h >> 13; 1.76 + h *= m; 1.77 + h ^= h >> 15; 1.78 + 1.79 + key->hash = h; 1.80 +} 1.81 + 1.82 +CxHashKey cx_hash_key_str(char const *str) { 1.83 + CxHashKey key; 1.84 + key.data.cstr = str; 1.85 + key.len = str == NULL ? 0 : (1 + strlen(str)); 1.86 + cx_hash_murmur(&key); 1.87 + return key; 1.88 +} 1.89 + 1.90 +CxHashKey cx_hash_key_bytes( 1.91 + unsigned char const *bytes, 1.92 + size_t len 1.93 +) { 1.94 + CxHashKey key; 1.95 + key.data.cbytes = bytes; 1.96 + key.len = len; 1.97 + cx_hash_murmur(&key); 1.98 + return key; 1.99 +} 1.100 + 1.101 +CxHashKey cx_hash_key( 1.102 + void *obj, 1.103 + size_t len 1.104 +) { 1.105 + CxHashKey key; 1.106 + key.data.obj = obj; 1.107 + key.len = len; 1.108 + cx_hash_murmur(&key); 1.109 + return key; 1.110 +}