Mon, 25 Jul 2022 15:34:19 +0200
#170 test cxBufferGet
universe@563 | 1 | /* |
universe@563 | 2 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. |
universe@563 | 3 | * |
universe@563 | 4 | * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved. |
universe@563 | 5 | * |
universe@563 | 6 | * Redistribution and use in source and binary forms, with or without |
universe@563 | 7 | * modification, are permitted provided that the following conditions are met: |
universe@563 | 8 | * |
universe@563 | 9 | * 1. Redistributions of source code must retain the above copyright |
universe@563 | 10 | * notice, this list of conditions and the following disclaimer. |
universe@563 | 11 | * |
universe@563 | 12 | * 2. Redistributions in binary form must reproduce the above copyright |
universe@563 | 13 | * notice, this list of conditions and the following disclaimer in the |
universe@563 | 14 | * documentation and/or other materials provided with the distribution. |
universe@563 | 15 | * |
universe@563 | 16 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
universe@563 | 17 | * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
universe@563 | 18 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
universe@563 | 19 | * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE |
universe@563 | 20 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
universe@563 | 21 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
universe@563 | 22 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
universe@563 | 23 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
universe@563 | 24 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
universe@563 | 25 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
universe@563 | 26 | * POSSIBILITY OF SUCH DAMAGE. |
universe@563 | 27 | */ |
universe@563 | 28 | |
universe@563 | 29 | #include "cx/hash_key.h" |
universe@563 | 30 | #include <string.h> |
universe@563 | 31 | |
universe@563 | 32 | void cx_hash_murmur(CxHashKey *key) { |
universe@563 | 33 | size_t len = key->len; |
universe@563 | 34 | unsigned char const *data = key->data.cbytes; |
universe@563 | 35 | |
universe@563 | 36 | unsigned m = 0x5bd1e995; |
universe@563 | 37 | unsigned r = 24; |
universe@563 | 38 | unsigned h = 25 ^ len; |
universe@563 | 39 | unsigned i = 0; |
universe@563 | 40 | while (len >= 4) { |
universe@563 | 41 | unsigned k = data[i + 0] & 0xFF; |
universe@563 | 42 | k |= (data[i + 1] & 0xFF) << 8; |
universe@563 | 43 | k |= (data[i + 2] & 0xFF) << 16; |
universe@563 | 44 | k |= (data[i + 3] & 0xFF) << 24; |
universe@563 | 45 | |
universe@563 | 46 | k *= m; |
universe@563 | 47 | k ^= k >> r; |
universe@563 | 48 | k *= m; |
universe@563 | 49 | |
universe@563 | 50 | h *= m; |
universe@563 | 51 | h ^= k; |
universe@563 | 52 | |
universe@563 | 53 | i += 4; |
universe@563 | 54 | len -= 4; |
universe@563 | 55 | } |
universe@563 | 56 | |
universe@563 | 57 | switch (len) { |
universe@563 | 58 | case 3: |
universe@563 | 59 | h ^= (data[i + 2] & 0xFF) << 16; |
universe@563 | 60 | __attribute__((__fallthrough__)); |
universe@563 | 61 | case 2: |
universe@563 | 62 | h ^= (data[i + 1] & 0xFF) << 8; |
universe@563 | 63 | __attribute__((__fallthrough__)); |
universe@563 | 64 | case 1: |
universe@563 | 65 | h ^= (data[i + 0] & 0xFF); |
universe@563 | 66 | h *= m; |
universe@563 | 67 | __attribute__((__fallthrough__)); |
universe@563 | 68 | default: |
universe@563 | 69 | /* do nothing */; |
universe@563 | 70 | } |
universe@563 | 71 | |
universe@563 | 72 | h ^= h >> 13; |
universe@563 | 73 | h *= m; |
universe@563 | 74 | h ^= h >> 15; |
universe@563 | 75 | |
universe@563 | 76 | key->hash = h; |
universe@563 | 77 | } |
universe@563 | 78 | |
universe@563 | 79 | CxHashKey cx_hash_key_str(char const *str) { |
universe@563 | 80 | CxHashKey key; |
universe@563 | 81 | key.data.cstr = str; |
universe@563 | 82 | key.len = str == NULL ? 0 : (1 + strlen(str)); |
universe@563 | 83 | cx_hash_murmur(&key); |
universe@563 | 84 | return key; |
universe@563 | 85 | } |
universe@563 | 86 | |
universe@563 | 87 | CxHashKey cx_hash_key_bytes( |
universe@563 | 88 | unsigned char const *bytes, |
universe@563 | 89 | size_t len |
universe@563 | 90 | ) { |
universe@563 | 91 | CxHashKey key; |
universe@563 | 92 | key.data.cbytes = bytes; |
universe@563 | 93 | key.len = len; |
universe@563 | 94 | cx_hash_murmur(&key); |
universe@563 | 95 | return key; |
universe@563 | 96 | } |
universe@563 | 97 | |
universe@563 | 98 | CxHashKey cx_hash_key( |
universe@563 | 99 | void *obj, |
universe@563 | 100 | size_t len |
universe@563 | 101 | ) { |
universe@563 | 102 | CxHashKey key; |
universe@563 | 103 | key.data.obj = obj; |
universe@563 | 104 | key.len = len; |
universe@563 | 105 | cx_hash_murmur(&key); |
universe@563 | 106 | return key; |
universe@563 | 107 | } |