1 | /* |
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2 | * hashmap.c |
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3 | * Copyright (c) 2009 Vedant Kumar |
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4 | * |
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5 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
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6 | * of this software and associated documentation files (the "Software"), to deal |
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7 | * in the Software without restriction, including without limitation the rights |
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8 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
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9 | * copies of the Software, and to permit persons to whom the Software is |
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10 | * furnished to do so, subject to the following conditions: |
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11 | * |
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12 | * The above copyright notice and this permission notice shall be included in |
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13 | * all copies or substantial portions of the Software. |
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14 | * |
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15 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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16 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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17 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
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18 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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19 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
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20 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
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21 | * THE SOFTWARE. |
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22 | */ |
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23 | #include <stdio.h> |
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24 | #include <string.h> |
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25 | #include "hashmap_public.h" |
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26 | |
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27 | struct key_val_map { |
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28 | key k; |
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29 | val v; |
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30 | }; |
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31 | |
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32 | struct hashmap { |
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33 | key_val_map *map; |
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34 | uint32_t size; |
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35 | uint32_t capacity; |
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36 | uint32_t (*hash_fn)(key); |
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37 | bool (*eq_fn)(key, key); |
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38 | #ifdef HMAP_DESTRUCTORS |
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39 | void (*del_fn)(val); |
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40 | #endif |
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41 | #ifdef HMAP_THREAD_SAFE |
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42 | sem_t lock; |
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43 | #endif |
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44 | }; |
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45 | |
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46 | // hashmaps need a hash function, an equality function, and a destructor |
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47 | hashmap* mk_hmap(uint32_t (*hash_fn)(key), |
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48 | bool (*eq_fn)(key, key) |
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49 | #ifdef HMAP_DESTRUCTORS |
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50 | , void (*del_fn)(val) |
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51 | #endif |
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52 | ) { |
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53 | |
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54 | hashmap* hmap = (hashmap*) malloc(sizeof(hashmap)); |
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55 | hmap->map = (key_val_map*) malloc(sizeof(key_val_map) * HMAP_PRESET_SIZE); |
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56 | bzero(hmap->map, sizeof(key_val_map) * HMAP_PRESET_SIZE); |
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57 | hmap->size = 0; |
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58 | hmap->capacity = HMAP_PRESET_SIZE; |
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59 | hmap->hash_fn = hash_fn; |
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60 | hmap->eq_fn = eq_fn; |
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61 | #ifdef HMAP_DESTRUCTORS |
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62 | hmap->del_fn = del_fn; |
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63 | #endif |
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64 | #ifdef HMAP_THREAD_SAFE |
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65 | sem_init(&hmap->lock, 0, 1); |
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66 | #endif |
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67 | return hmap; |
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68 | } |
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69 | |
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70 | void free_hmap(hashmap* hmap) { |
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71 | #ifdef HMAP_THREAD_SAFE |
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72 | sem_wait(&hmap->lock); |
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73 | #endif |
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74 | |
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75 | #ifdef HMAP_DESTRUCTORS |
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76 | static uint32_t it; |
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77 | for (it=0; it < hmap->size; ++it) { |
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78 | if (hmap->map[it].v != NULL) { |
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79 | hmap->del_fn(hmap->map[it].v); |
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80 | } |
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81 | } |
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82 | #endif |
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83 | |
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84 | free(hmap->map); |
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85 | |
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86 | #ifdef HMAP_THREAD_SAFE |
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87 | sem_post(&hmap->lock); |
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88 | #endif |
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89 | |
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90 | free(hmap); |
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91 | } |
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92 | |
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93 | static void __oa_hmap_add(key_val_map* map, uint32_t size, |
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94 | uint32_t (*hash_fn)(key), |
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95 | key in, val out) { |
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96 | static uint32_t hash; |
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97 | hash = hash_fn(in) % size; |
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98 | |
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99 | uint32_t count = 0; |
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100 | while (map[hash].k != NULL) { |
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101 | hash = (hash + 1) % size; |
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102 | count++; |
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103 | if (count > size) { |
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104 | fprintf(stdout, "Hashmap has no free entries \n"); |
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105 | exit(0); |
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106 | } |
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107 | } |
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108 | |
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109 | map[hash].k = in; |
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110 | map[hash].v = out; |
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111 | |
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112 | } |
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113 | |
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114 | bool __hmap_add(hashmap* hmap, key in, val out) { |
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115 | #ifdef HMAP_THREAD_SAFE |
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116 | sem_wait(&hmap->lock); |
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117 | #endif |
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118 | |
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119 | // performace degrades after a certain load |
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120 | if (((float) hmap->size) / hmap->capacity > 0.70) { |
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121 | key_val_map* temp = (key_val_map*) malloc(sizeof(key_val_map) * hmap->capacity * HMAP_GROWTH_RATE); |
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122 | if (temp != NULL) { |
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123 | //hmap->capacity *= HMAP_GROWTH_RATE; |
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124 | } else { |
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125 | #ifdef HMAP_THREAD_SAFE |
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126 | sem_post(&hmap->lock); |
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127 | #endif |
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128 | // we're out of memory |
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129 | return false; |
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130 | } |
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131 | |
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132 | // init new hashmap |
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133 | bzero(temp, sizeof(key_val_map) * hmap->capacity * HMAP_GROWTH_RATE); |
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134 | |
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135 | // re-posn all elements |
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136 | static uint32_t it; |
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137 | for (it=0; it < hmap->capacity; ++it) { |
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138 | if (hmap->map[it].k != NULL) { |
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139 | __oa_hmap_add(temp, hmap->capacity * HMAP_GROWTH_RATE, hmap->hash_fn, hmap->map[it].k, hmap->map[it].v); |
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140 | } |
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141 | } |
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142 | |
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143 | // swap out the old map with the new one |
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144 | free(hmap->map); |
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145 | hmap->map = temp; |
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146 | hmap->capacity *= HMAP_GROWTH_RATE; |
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147 | } |
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148 | |
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149 | __oa_hmap_add(hmap->map, hmap->capacity, hmap->hash_fn, in, out); |
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150 | hmap->size += 1; |
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151 | |
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152 | #ifdef HMAP_THREAD_SAFE |
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153 | sem_post(&hmap->lock); |
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154 | #endif |
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155 | return true; |
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156 | } |
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157 | |
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158 | val __hmap_get(hashmap* hmap, key in) { |
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159 | #ifdef HMAP_THREAD_SAFE |
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160 | sem_wait(&hmap->lock); |
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161 | #endif |
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162 | |
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163 | static uint32_t hash; |
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164 | hash = hmap->hash_fn(in) % hmap->capacity; |
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165 | |
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166 | while (hmap->map[hash].k != NULL) { |
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167 | if (hmap->eq_fn(in, hmap->map[hash].k)) { |
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168 | #ifdef HMAP_THREAD_SAFE |
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169 | sem_post(&hmap->lock); |
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170 | #endif |
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171 | return hmap->map[hash].v; |
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172 | } |
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173 | |
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174 | hash = (hash + 1) % hmap->capacity; |
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175 | } |
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176 | |
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177 | |
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178 | #ifdef HMAP_THREAD_SAFE |
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179 | sem_post(&hmap->lock); |
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180 | #endif |
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181 | |
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182 | return NULL; |
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183 | } |
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184 | |
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185 | #ifdef HMAP_MAKE_HASHFN |
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186 | // Robert Jenkins' 32 bit integer hash function |
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187 | uint32_t int_hash_fn(key in) { |
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188 | static uint32_t a; |
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189 | a = *((uint32_t*) in); |
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190 | |
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191 | a = (a+0x7ed55d16) + (a<<12); |
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192 | a = (a^0xc761c23c) ^ (a>>19); |
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193 | a = (a+0x165667b1) + (a<<5); |
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194 | a = (a+0xd3a2646c) ^ (a<<9); |
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195 | a = (a+0xfd7046c5) + (a<<3); |
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196 | a = (a^0xb55a4f09) ^ (a>>16); |
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197 | |
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198 | return a; |
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199 | } |
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200 | |
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201 | bool int_eq_fn(key a, key b) { |
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202 | return *((uint32_t*) a) == *((uint32_t*) b) ? true : false; |
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203 | } |
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204 | |
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205 | #endif |
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