34
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1
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2 /*
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3 * Copyright (C) Igor Sysoev
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4 */
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5
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6
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7 #include <ngx_config.h>
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8 #include <ngx_core.h>
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9
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10
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11 static void *ngx_radix_alloc(ngx_radix_tree_t *tree);
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12
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13
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36
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14 ngx_radix_tree_t *
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15 ngx_radix_tree_create(ngx_pool_t *pool, ngx_uint_t preallocate)
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34
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16 {
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36
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17 uint32_t key, mask, inc;
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18 ngx_radix_tree_t *tree;
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19
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20 if (!(tree = ngx_palloc(pool, sizeof(ngx_radix_tree_t)))) {
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21 return NULL;
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22 }
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23
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24 tree->pool = pool;
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25 tree->free = NULL;
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26 tree->start = NULL;
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27 tree->size = 0;
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28
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29 if (!(tree->root = ngx_radix_alloc(tree))) {
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30 return NULL;
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31 }
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32
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33 tree->root->right = NULL;
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34 tree->root->left = NULL;
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35 tree->root->parent = NULL;
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36 tree->root->value = NGX_RADIX_NO_VALUE;
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37
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36
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38 /*
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39 * We preallocate the first nodes: 0, 1, 00, 01, 10, 11, 000, 001, etc.,
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40 * to increase the TLB hits even if for the first lookup iterations.
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41 * On the 32-bit platforms the 7 preallocated bits takes continuous 4K,
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42 * 8 - 8K, 9 - 16K, etc.
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43 */
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44
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45 mask = 0;
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46 inc = 0x80000000;
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47
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48 while (preallocate--) {
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49
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50 key = 0;
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51 mask >>= 1;
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52 mask |= 0x80000000;
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53
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54 do {
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55 if (ngx_radix32tree_insert(tree, key, mask, NGX_RADIX_NO_VALUE)
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56 != NGX_OK)
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57 {
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58 return NULL;
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59 }
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60
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61 key += inc;
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62
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63 } while (key);
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64
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65 inc >>= 1;
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66 }
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67
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68 return tree;
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69 }
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70
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71
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36
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72 ngx_int_t
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73 ngx_radix32tree_insert(ngx_radix_tree_t *tree, uint32_t key, uint32_t mask,
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74 uintptr_t value)
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34
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75 {
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76 uint32_t bit;
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77 ngx_radix_node_t *node, *next;
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78
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79 bit = 0x80000000;
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80
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81 node = tree->root;
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82 next = tree->root;
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83
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84 while (bit & mask) {
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85 if (key & bit) {
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86 next = node->right;
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87
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88 } else {
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89 next = node->left;
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90 }
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91
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92 if (next == NULL) {
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93 break;
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94 }
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95
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96 bit >>= 1;
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97 node = next;
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98 }
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99
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100 if (next) {
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101 if (node->value != NGX_RADIX_NO_VALUE) {
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102 return NGX_BUSY;
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103 }
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104
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105 node->value = value;
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106 return NGX_OK;
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107 }
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108
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109 while (bit & mask) {
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110 if (!(next = ngx_radix_alloc(tree))) {
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111 return NGX_ERROR;
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112 }
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113
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114 next->right = NULL;
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115 next->left = NULL;
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116 next->parent = node;
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117 next->value = NGX_RADIX_NO_VALUE;
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118
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119 if (key & bit) {
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120 node->right = next;
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121
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122 } else {
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123 node->left = next;
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124 }
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125
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126 bit >>= 1;
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127 node = next;
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128 }
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129
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130 node->value = value;
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131
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132 return NGX_OK;
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133 }
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134
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135
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36
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136 ngx_int_t
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137 ngx_radix32tree_delete(ngx_radix_tree_t *tree, uint32_t key, uint32_t mask)
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34
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138 {
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139 uint32_t bit;
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140 ngx_radix_node_t *node;
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141
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142 bit = 0x80000000;
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143 node = tree->root;
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144
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145 while (node && (bit & mask)) {
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146 if (key & bit) {
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147 node = node->right;
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148
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149 } else {
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150 node = node->left;
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151 }
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152
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153 bit >>= 1;
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154 }
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155
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156 if (node == NULL) {
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157 return NGX_ERROR;
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158 }
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159
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160 if (node->right || node->left) {
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161 if (node->value != NGX_RADIX_NO_VALUE) {
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162 node->value = NGX_RADIX_NO_VALUE;
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163 return NGX_OK;
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164 }
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165
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166 return NGX_ERROR;
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167 }
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168
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169 for ( ;; ) {
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170 if (node->parent->right == node) {
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171 node->parent->right = NULL;
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172 } else {
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173 node->parent->left = NULL;
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174 }
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175
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176 node->right = tree->free;
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177 tree->free = node;
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178
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179 node = node->parent;
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180
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181 if (node->right
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182 || node->left
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183 || node->value != NGX_RADIX_NO_VALUE
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184 || node->parent == NULL)
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185 {
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186 break;
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187 }
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188 }
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189
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190 return NGX_OK;
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191 }
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192
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193
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36
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194 uintptr_t
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195 ngx_radix32tree_find(ngx_radix_tree_t *tree, uint32_t key)
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34
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196 {
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197 uint32_t bit;
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198 uintptr_t value;
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199 ngx_radix_node_t *node;
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200
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201 bit = 0x80000000;
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202 value = NGX_RADIX_NO_VALUE;
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203 node = tree->root;
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204
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205 while (node) {
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206 if (node->value != NGX_RADIX_NO_VALUE) {
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207 value = node->value;
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208 }
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209
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210 if (key & bit) {
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211 node = node->right;
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212
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213 } else {
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214 node = node->left;
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215 }
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216
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217 bit >>= 1;
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218 }
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219
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220 return value;
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221 }
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222
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223
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36
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224 static void *
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225 ngx_radix_alloc(ngx_radix_tree_t *tree)
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34
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226 {
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227 char *p;
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228
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229 if (tree->free) {
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230 p = (char *) tree->free;
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231 tree->free = tree->free->right;
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232 return p;
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233 }
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234
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235 if (tree->size < sizeof(ngx_radix_node_t)) {
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236 if (!(tree->start = ngx_palloc(tree->pool, ngx_pagesize))) {
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237 return NULL;
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238 }
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239
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240 tree->size = ngx_pagesize;
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241 }
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242
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243 p = tree->start;
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244 tree->start += sizeof(ngx_radix_node_t);
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245 tree->size -= sizeof(ngx_radix_node_t);
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246
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247 return p;
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248 }
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