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 "cx/compare.h"
31 #include <string.h>
32
33 void cx_hash_murmur(CxHashKey *key) {
34 const unsigned char *data = key->data;
35 if (data == NULL) {
36 // extension: special value for NULL
37 key->hash = 1574210520u;
38 return;
39 }
40 size_t len = key->len;
41
42 unsigned m = 0x5bd1e995;
43 unsigned r = 24;
44 unsigned h = 25 ^ (unsigned) len;
45 unsigned i = 0;
46 while (len >= 4) {
47 unsigned k = data[i + 0] & 0xFF;
48 k |= (data[i + 1] & 0xFF) << 8;
49 k |= (data[i + 2] & 0xFF) << 16;
50 k |= (data[i + 3] & 0xFF) << 24;
51
52 k *= m;
53 k ^= k >> r;
54 k *= m;
55
56 h *= m;
57 h ^= k;
58
59 i += 4;
60 len -= 4;
61 }
62
63 switch (len) {
64 case 3:
65 h ^= (data[i + 2] & 0xFF) << 16;
66 cx_attr_fallthrough;
67 case 2:
68 h ^= (data[i + 1] & 0xFF) << 8;
69 cx_attr_fallthrough;
70 case 1:
71 h ^= (data[i + 0] & 0xFF);
72 h *= m;
73 cx_attr_fallthrough;
74 default: // do nothing
75 ;
76 }
77
78 h ^= h >> 13;
79 h *= m;
80 h ^= h >> 15;
81
82 key->hash = h;
83 }
84
85
86 uint32_t cx_hash_u32(uint32_t x) {
87 x = ((x >> 16) ^ x) * 0x45d9f3bu;
88 x = ((x >> 16) ^ x) * 0x45d9f3bu;
89 x = (x >> 16) ^ x;
90 return x;
91 }
92
93 uint64_t cx_hash_u64(uint64_t x) {
94 x = (x ^ (x >> 30)) * UINT64_C(0xbf58476d1ce4e5b9);
95 x = (x ^ (x >> 27)) * UINT64_C(0x94d049bb133111eb);
96 x = x ^ (x >> 31);
97 return x;
98 }
99
100 CxHashKey cx_hash_key_str(const char *str) {
101 CxHashKey key;
102 key.data = str;
103 key.len = str == NULL ? 0 : strlen(str);
104 cx_hash_murmur(&key);
105 return key;
106 }
107
108 CxHashKey cx_hash_key_ustr(unsigned const char *str) {
109 CxHashKey key;
110 key.data = str;
111 key.len = str == NULL ? 0 : strlen((const char*)str);
112 cx_hash_murmur(&key);
113 return key;
114 }
115
116 CxHashKey cx_hash_key_cxstr(cxstring str) {
117 return cx_hash_key(str.ptr, str.length);
118 }
119
120 CxHashKey cx_hash_key_mutstr(cxmutstr str) {
121 return cx_hash_key(str.ptr, str.length);
122 }
123
124 CxHashKey cx_hash_key_bytes(
125 const unsigned char *bytes,
126 size_t len
127 ) {
128 CxHashKey key;
129 key.data = bytes;
130 key.len = len;
131 cx_hash_murmur(&key);
132 return key;
133 }
134
135 CxHashKey cx_hash_key(
136 const void *obj,
137 size_t len
138 ) {
139 CxHashKey key;
140 key.data = obj;
141 key.len = len;
142 cx_hash_murmur(&key);
143 return key;
144 }
145
146 CxHashKey cx_hash_key_u32(uint32_t x) {
147 CxHashKey key;
148 key.data = NULL;
149 key.len = 0;
150 key.hash = cx_hash_u32(x);
151 return key;
152 }
153
154 CxHashKey cx_hash_key_u64(uint64_t x) {
155 CxHashKey key;
156 key.data = NULL;
157 key.len = 0;
158 key.hash = cx_hash_u64(x);
159 return key;
160 }
161
162 int cx_hash_key_cmp(const void *l, const void *r) {
163 const CxHashKey *left = l;
164 const CxHashKey *right = r;
165 int d;
166 d = cx_vcmp_uint64(left->hash, right->hash);
167 if (d != 0) return d;
168 d = cx_vcmp_size(left->len, right->len);
169 if (d != 0) return d;
170 if (left->len == 0) return 0;
171 return memcmp(left->data, right->data, left->len);
172 }
173