1 /* |
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2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. |
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3 * |
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4 * Copyright 2016 Olaf Wintermann. All rights reserved. |
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5 * |
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6 * Redistribution and use in source and binary forms, with or without |
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7 * modification, are permitted provided that the following conditions are met: |
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8 * |
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9 * 1. Redistributions of source code must retain the above copyright |
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10 * notice, this list of conditions and the following disclaimer. |
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11 * |
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12 * 2. Redistributions in binary form must reproduce the above copyright |
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13 * notice, this list of conditions and the following disclaimer in the |
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14 * documentation and/or other materials provided with the distribution. |
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15 * |
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16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
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17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE |
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20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
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21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
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22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
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23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
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24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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26 * POSSIBILITY OF SUCH DAMAGE. |
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27 */ |
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28 |
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29 /** |
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30 * @file map.h |
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31 * |
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32 * Hash map implementation. |
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33 * |
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34 * This implementation uses murmur hash 2 and separate chaining with linked |
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35 * lists. |
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36 * |
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37 * @author Mike Becker |
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38 * @author Olaf Wintermann |
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39 */ |
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40 |
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41 #ifndef UCX_MAP_H |
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42 #define UCX_MAP_H |
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43 |
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44 #include "ucx.h" |
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45 #include "string.h" |
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46 #include "allocator.h" |
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47 #include <stdio.h> |
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48 |
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49 #ifdef __cplusplus |
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50 extern "C" { |
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51 #endif |
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52 |
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53 /** |
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54 * Loop statement for UCX maps. |
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55 * |
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56 * The <code>key</code> variable is implicitly defined, but the |
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57 * <code>value</code> variable must be already declared as type information |
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58 * cannot be inferred. |
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59 * |
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60 * @param key the variable name for the key |
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61 * @param value the variable name for the value |
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62 * @param iter a UcxMapIterator |
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63 * @see ucx_map_iterator() |
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64 */ |
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65 #define UCX_MAP_FOREACH(key,value,iter) \ |
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66 for(UcxKey key;ucx_map_iter_next(&iter,&key, (void**)&value);) |
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67 |
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68 /** Type for the UCX map. @see UcxMap */ |
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69 typedef struct UcxMap UcxMap; |
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70 |
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71 /** Type for a key of a UcxMap. @see UcxKey */ |
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72 typedef struct UcxKey UcxKey; |
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73 |
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74 /** Type for an element of a UcxMap. @see UcxMapElement */ |
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75 typedef struct UcxMapElement UcxMapElement; |
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76 |
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77 /** Type for an iterator over a UcxMap. @see UcxMapIterator */ |
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78 typedef struct UcxMapIterator UcxMapIterator; |
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79 |
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80 /** Structure for the UCX map. */ |
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81 struct UcxMap { |
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82 /** An allocator that is used for the map elements. */ |
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83 UcxAllocator *allocator; |
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84 /** The array of map element lists. */ |
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85 UcxMapElement **map; |
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86 /** The size of the map is the length of the element list array. */ |
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87 size_t size; |
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88 /** The count of elements currently stored in this map. */ |
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89 size_t count; |
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90 }; |
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91 |
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92 /** Structure for a key of a UcxMap. */ |
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93 struct UcxKey { |
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94 /** The key data. */ |
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95 void *data; |
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96 /** The length of the key data. */ |
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97 size_t len; |
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98 /** The hash value of the key data. */ |
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99 int hash; |
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100 }; |
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101 |
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102 /** Structure for an element of a UcxMap. */ |
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103 struct UcxMapElement { |
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104 /** The value data. */ |
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105 void *data; |
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106 |
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107 /** A pointer to the next element in the current list. */ |
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108 UcxMapElement *next; |
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109 |
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110 /** The corresponding key. */ |
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111 UcxKey key; |
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112 }; |
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113 |
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114 /** Structure for an iterator over a UcxMap. */ |
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115 struct UcxMapIterator { |
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116 /** The map to iterate over. */ |
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117 UcxMap *map; |
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118 |
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119 /** The current map element. */ |
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120 UcxMapElement *cur; |
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121 |
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122 /** |
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123 * The current index of the element list array. |
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124 * <b>Attention: </b> this is <b>NOT</b> the element index! Do <b>NOT</b> |
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125 * manually iterate over the map by increasing this index. Use |
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126 * ucx_map_iter_next(). |
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127 * @see UcxMap.map*/ |
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128 size_t index; |
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129 }; |
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130 |
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131 /** |
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132 * Creates a new hash map with the specified size. |
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133 * @param size the size of the hash map |
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134 * @return a pointer to the new hash map |
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135 */ |
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136 UcxMap *ucx_map_new(size_t size); |
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137 |
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138 /** |
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139 * Creates a new hash map with the specified size using a UcxAllocator. |
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140 * @param allocator the allocator to use |
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141 * @param size the size of the hash map |
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142 * @return a pointer to the new hash map |
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143 */ |
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144 UcxMap *ucx_map_new_a(UcxAllocator *allocator, size_t size); |
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145 |
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146 /** |
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147 * Frees a hash map. |
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148 * |
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149 * <b>Note:</b> the contents are <b>not</b> freed, use ucx_map_free_content() |
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150 * before calling this function to achieve that. |
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151 * |
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152 * @param map the map to be freed |
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153 * @see ucx_map_free_content() |
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154 */ |
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155 void ucx_map_free(UcxMap *map); |
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156 |
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157 /** |
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158 * Frees the contents of a hash map. |
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159 * |
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160 * This is a convenience function that iterates over the map and passes all |
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161 * values to the specified destructor function (e.g. stdlib free()). |
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162 * |
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163 * You must ensure, that it is valid to pass each value in the map to the same |
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164 * destructor function. |
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165 * |
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166 * You should free or clear the map afterwards, as the contents will be invalid. |
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167 * |
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168 * @param map for which the contents shall be freed |
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169 * @param destr pointer to the destructor function |
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170 * @see ucx_map_free() |
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171 * @see ucx_map_clear() |
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172 */ |
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173 void ucx_map_free_content(UcxMap *map, ucx_destructor destr); |
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174 |
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175 /** |
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176 * Clears a hash map. |
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177 * |
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178 * <b>Note:</b> the contents are <b>not</b> freed, use ucx_map_free_content() |
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179 * before calling this function to achieve that. |
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180 * |
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181 * @param map the map to be cleared |
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182 * @see ucx_map_free_content() |
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183 */ |
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184 void ucx_map_clear(UcxMap *map); |
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185 |
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186 |
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187 /** |
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188 * Copies contents from a map to another map using a copy function. |
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189 * |
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190 * <b>Note:</b> The destination map does not need to be empty. However, if it |
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191 * contains data with keys that are also present in the source map, the contents |
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192 * are overwritten. |
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193 * |
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194 * @param from the source map |
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195 * @param to the destination map |
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196 * @param fnc the copy function or <code>NULL</code> if the pointer address |
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197 * shall be copied |
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198 * @param data additional data for the copy function |
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199 * @return 0 on success or a non-zero value on memory allocation errors |
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200 */ |
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201 int ucx_map_copy(UcxMap *restrict from, UcxMap *restrict to, |
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202 copy_func fnc, void *data); |
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203 |
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204 /** |
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205 * Clones the map and rehashes if necessary. |
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206 * |
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207 * <b>Note:</b> In contrast to ucx_map_rehash() the load factor is irrelevant. |
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208 * This function <i>always</i> ensures a new UcxMap.size of at least |
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209 * 2.5*UcxMap.count. |
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210 * |
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211 * @param map the map to clone |
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212 * @param fnc the copy function to use or <code>NULL</code> if the new and |
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213 * the old map shall share the data pointers |
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214 * @param data additional data for the copy function |
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215 * @return the cloned map |
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216 * @see ucx_map_copy() |
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217 */ |
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218 UcxMap *ucx_map_clone(UcxMap *map, copy_func fnc, void *data); |
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219 |
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220 /** |
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221 * Increases size of the hash map, if necessary. |
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222 * |
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223 * The load value is 0.75*UcxMap.size. If the element count exceeds the load |
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224 * value, the map needs to be rehashed. Otherwise no action is performed and |
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225 * this function simply returns 0. |
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226 * |
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227 * The rehashing process ensures, that the UcxMap.size is at least |
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228 * 2.5*UcxMap.count. So there is enough room for additional elements without |
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229 * the need of another soon rehashing. |
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230 * |
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231 * You can use this function to dramatically increase access performance. |
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232 * |
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233 * @param map the map to rehash |
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234 * @return 1, if a memory allocation error occurred, 0 otherwise |
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235 */ |
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236 int ucx_map_rehash(UcxMap *map); |
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237 |
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238 /** |
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239 * Puts a key/value-pair into the map. |
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240 * |
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241 * @param map the map |
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242 * @param key the key |
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243 * @param value the value |
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244 * @return 0 on success, non-zero value on failure |
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245 */ |
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246 int ucx_map_put(UcxMap *map, UcxKey key, void *value); |
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247 |
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248 /** |
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249 * Retrieves a value by using a key. |
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250 * |
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251 * @param map the map |
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252 * @param key the key |
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253 * @return the value |
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254 */ |
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255 void* ucx_map_get(UcxMap *map, UcxKey key); |
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256 |
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257 /** |
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258 * Removes a key/value-pair from the map by using the key. |
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259 * |
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260 * @param map the map |
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261 * @param key the key |
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262 * @return the removed value |
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263 */ |
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264 void* ucx_map_remove(UcxMap *map, UcxKey key); |
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265 |
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266 /** |
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267 * Shorthand for putting data with a sstr_t key into the map. |
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268 * @param map the map |
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269 * @param key the key |
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270 * @param value the value |
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271 * @return 0 on success, non-zero value on failure |
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272 * @see ucx_map_put() |
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273 */ |
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274 #define ucx_map_sstr_put(map, key, value) \ |
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275 ucx_map_put(map, ucx_key(key.ptr, key.length), (void*)value) |
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276 |
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277 /** |
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278 * Shorthand for putting data with a C string key into the map. |
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279 * @param map the map |
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280 * @param key the key |
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281 * @param value the value |
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282 * @return 0 on success, non-zero value on failure |
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283 * @see ucx_map_put() |
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284 */ |
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285 #define ucx_map_cstr_put(map, key, value) \ |
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286 ucx_map_put(map, ucx_key((void*)key, strlen(key)), (void*)value) |
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287 |
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288 /** |
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289 * Shorthand for putting data with an integer key into the map. |
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290 * @param map the map |
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291 * @param key the key |
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292 * @param value the value |
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293 * @return 0 on success, non-zero value on failure |
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294 * @see ucx_map_put() |
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295 */ |
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296 #define ucx_map_int_put(map, key, value) \ |
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297 ucx_map_put(map, ucx_key((void*)&key, sizeof(key)), (void*)value) |
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298 |
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299 /** |
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300 * Shorthand for getting data from the map with a sstr_t key. |
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301 * @param map the map |
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302 * @param key the key |
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303 * @return the value |
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304 * @see ucx_map_get() |
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305 */ |
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306 #define ucx_map_sstr_get(map, key) \ |
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307 ucx_map_get(map, ucx_key(key.ptr, key.length)) |
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308 |
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309 /** |
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310 * Shorthand for getting data from the map with a C string key. |
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311 * @param map the map |
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312 * @param key the key |
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313 * @return the value |
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314 * @see ucx_map_get() |
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315 */ |
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316 #define ucx_map_cstr_get(map, key) \ |
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317 ucx_map_get(map, ucx_key((void*)key, strlen(key))) |
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318 |
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319 /** |
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320 * Shorthand for getting data from the map with an integer key. |
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321 * @param map the map |
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322 * @param key the key |
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323 * @return the value |
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324 * @see ucx_map_get() |
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325 */ |
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326 #define ucx_map_int_get(map, key) \ |
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327 ucx_map_get(map, ucx_key((void*)&key, sizeof(int))) |
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328 |
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329 /** |
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330 * Shorthand for removing data from the map with a sstr_t key. |
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331 * @param map the map |
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332 * @param key the key |
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333 * @return the removed value |
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334 * @see ucx_map_remove() |
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335 */ |
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336 #define ucx_map_sstr_remove(map, key) \ |
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337 ucx_map_remove(map, ucx_key(key.ptr, key.length)) |
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338 |
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339 /** |
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340 * Shorthand for removing data from the map with a C string key. |
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341 * @param map the map |
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342 * @param key the key |
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343 * @return the removed value |
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344 * @see ucx_map_remove() |
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345 */ |
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346 #define ucx_map_cstr_remove(map, key) \ |
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347 ucx_map_remove(map, ucx_key((void*)key, strlen(key))) |
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348 |
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349 /** |
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350 * Shorthand for removing data from the map with an integer key. |
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351 * @param map the map |
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352 * @param key the key |
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353 * @return the removed value |
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354 * @see ucx_map_remove() |
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355 */ |
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356 #define ucx_map_int_remove(map, key) \ |
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357 ucx_map_remove(map, ucx_key((void*)&key, sizeof(key))) |
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358 |
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359 /** |
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360 * Creates a UcxKey based on the given data. |
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361 * |
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362 * This function implicitly computes the hash. |
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363 * |
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364 * @param data the data for the key |
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365 * @param len the length of the data |
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366 * @return a UcxKey with implicitly computed hash |
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367 * @see ucx_hash() |
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368 */ |
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369 UcxKey ucx_key(void *data, size_t len); |
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370 |
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371 /** |
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372 * Computes a murmur hash-2. |
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373 * |
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374 * @param data the data to hash |
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375 * @param len the length of the data |
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376 * @return the murmur hash-2 of the data |
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377 */ |
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378 int ucx_hash(const char *data, size_t len); |
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379 |
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380 /** |
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381 * Creates an iterator for a map. |
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382 * |
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383 * <b>Note:</b> A UcxMapIterator iterates over all elements in all element |
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384 * lists successively. Therefore the order highly depends on the key hashes and |
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385 * may vary under different map sizes. So generally you may <b>NOT</b> rely on |
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386 * the iteration order. |
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387 * |
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388 * <b>Note:</b> The iterator is <b>NOT</b> initialized. You need to call |
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389 * ucx_map_iter_next() at least once before accessing any information. However, |
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390 * it is not recommended to access the fields of a UcxMapIterator directly. |
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391 * |
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392 * @param map the map to create the iterator for |
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393 * @return an iterator initialized on the first element of the |
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394 * first element list |
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395 * @see ucx_map_iter_next() |
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396 */ |
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397 UcxMapIterator ucx_map_iterator(UcxMap *map); |
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398 |
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399 /** |
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400 * Proceeds to the next element of the map (if any). |
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401 * |
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402 * Subsequent calls on the same iterator proceed to the next element and |
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403 * store the key/value-pair into the memory specified as arguments of this |
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404 * function. |
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405 * |
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406 * If no further elements are found, this function returns zero and leaves the |
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407 * last found key/value-pair in memory. |
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408 * |
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409 * @param iterator the iterator to use |
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410 * @param key a pointer to the memory where to store the key |
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411 * @param value a pointer to the memory where to store the value |
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412 * @return 1, if another element was found, 0 if all elements has been processed |
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413 * @see ucx_map_iterator() |
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414 */ |
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415 int ucx_map_iter_next(UcxMapIterator *iterator, UcxKey *key, void **value); |
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416 |
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417 |
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418 #ifdef __cplusplus |
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419 } |
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420 #endif |
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421 |
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422 #endif /* UCX_MAP_H */ |
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423 |
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