34
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1
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2 /*
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3 * Copyright (C) Igor Sysoev
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660
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4 * Copyright (C) Nginx, Inc.
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34
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5 */
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6
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7
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8 #include <ngx_config.h>
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9 #include <ngx_core.h>
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10
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11
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12 static void *ngx_radix_alloc(ngx_radix_tree_t *tree);
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13
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14
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36
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15 ngx_radix_tree_t *
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38
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16 ngx_radix_tree_create(ngx_pool_t *pool, ngx_int_t preallocate)
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34
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17 {
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36
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18 uint32_t key, mask, inc;
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19 ngx_radix_tree_t *tree;
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20
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50
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21 tree = ngx_palloc(pool, sizeof(ngx_radix_tree_t));
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22 if (tree == NULL) {
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23 return NULL;
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24 }
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25
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26 tree->pool = pool;
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27 tree->free = NULL;
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28 tree->start = NULL;
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29 tree->size = 0;
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30
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50
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31 tree->root = ngx_radix_alloc(tree);
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32 if (tree->root == NULL) {
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34
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33 return NULL;
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34 }
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35
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36 tree->root->right = NULL;
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37 tree->root->left = NULL;
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38 tree->root->parent = NULL;
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39 tree->root->value = NGX_RADIX_NO_VALUE;
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40
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38
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41 if (preallocate == 0) {
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42 return tree;
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43 }
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44
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36
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45 /*
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426
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46 * Preallocation of first nodes : 0, 1, 00, 01, 10, 11, 000, 001, etc.
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47 * increases TLB hits even if for first lookup iterations.
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48 * On 32-bit platforms the 7 preallocated bits takes continuous 4K,
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49 * 8 - 8K, 9 - 16K, etc. On 64-bit platforms the 6 preallocated bits
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38
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50 * takes continuous 4K, 7 - 8K, 8 - 16K, etc. There is no sense to
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51 * to preallocate more than one page, because further preallocation
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426
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52 * distributes the only bit per page. Instead, a random insertion
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53 * may distribute several bits per page.
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54 *
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55 * Thus, by default we preallocate maximum
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56 * 6 bits on amd64 (64-bit platform and 4K pages)
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57 * 7 bits on i386 (32-bit platform and 4K pages)
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58 * 7 bits on sparc64 in 64-bit mode (8K pages)
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59 * 8 bits on sparc64 in 32-bit mode (8K pages)
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36
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60 */
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61
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38
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62 if (preallocate == -1) {
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63 switch (ngx_pagesize / sizeof(ngx_radix_tree_t)) {
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64
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65 /* amd64 */
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66 case 128:
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67 preallocate = 6;
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68 break;
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69
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70 /* i386, sparc64 */
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71 case 256:
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72 preallocate = 7;
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73 break;
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74
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75 /* sparc64 in 32-bit mode */
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76 default:
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77 preallocate = 8;
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78 }
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79 }
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80
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81 mask = 0;
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82 inc = 0x80000000;
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83
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84 while (preallocate--) {
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85
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86 key = 0;
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87 mask >>= 1;
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88 mask |= 0x80000000;
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89
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90 do {
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91 if (ngx_radix32tree_insert(tree, key, mask, NGX_RADIX_NO_VALUE)
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290
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92 != NGX_OK)
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93 {
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94 return NULL;
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95 }
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96
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97 key += inc;
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98
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99 } while (key);
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100
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101 inc >>= 1;
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102 }
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103
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104 return tree;
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105 }
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106
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107
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108 ngx_int_t
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109 ngx_radix32tree_insert(ngx_radix_tree_t *tree, uint32_t key, uint32_t mask,
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110 uintptr_t value)
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111 {
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112 uint32_t bit;
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113 ngx_radix_node_t *node, *next;
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114
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115 bit = 0x80000000;
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116
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117 node = tree->root;
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118 next = tree->root;
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119
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120 while (bit & mask) {
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121 if (key & bit) {
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122 next = node->right;
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123
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124 } else {
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125 next = node->left;
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126 }
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127
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128 if (next == NULL) {
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129 break;
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130 }
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131
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132 bit >>= 1;
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133 node = next;
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134 }
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135
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136 if (next) {
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137 if (node->value != NGX_RADIX_NO_VALUE) {
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138 return NGX_BUSY;
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139 }
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140
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141 node->value = value;
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142 return NGX_OK;
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143 }
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144
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145 while (bit & mask) {
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146 next = ngx_radix_alloc(tree);
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147 if (next == NULL) {
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148 return NGX_ERROR;
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149 }
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150
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151 next->right = NULL;
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152 next->left = NULL;
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153 next->parent = node;
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154 next->value = NGX_RADIX_NO_VALUE;
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155
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156 if (key & bit) {
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157 node->right = next;
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158
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159 } else {
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160 node->left = next;
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161 }
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162
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163 bit >>= 1;
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164 node = next;
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165 }
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166
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167 node->value = value;
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168
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169 return NGX_OK;
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170 }
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171
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172
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173 ngx_int_t
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174 ngx_radix32tree_delete(ngx_radix_tree_t *tree, uint32_t key, uint32_t mask)
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175 {
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176 uint32_t bit;
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177 ngx_radix_node_t *node;
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178
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179 bit = 0x80000000;
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180 node = tree->root;
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181
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182 while (node && (bit & mask)) {
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183 if (key & bit) {
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184 node = node->right;
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185
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186 } else {
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187 node = node->left;
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188 }
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189
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190 bit >>= 1;
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191 }
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192
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193 if (node == NULL) {
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194 return NGX_ERROR;
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195 }
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196
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197 if (node->right || node->left) {
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198 if (node->value != NGX_RADIX_NO_VALUE) {
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199 node->value = NGX_RADIX_NO_VALUE;
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200 return NGX_OK;
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201 }
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202
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203 return NGX_ERROR;
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204 }
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205
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206 for ( ;; ) {
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207 if (node->parent->right == node) {
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208 node->parent->right = NULL;
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112
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209
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210 } else {
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211 node->parent->left = NULL;
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212 }
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213
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214 node->right = tree->free;
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215 tree->free = node;
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216
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217 node = node->parent;
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218
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112
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219 if (node->right || node->left) {
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220 break;
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221 }
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222
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223 if (node->value != NGX_RADIX_NO_VALUE) {
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224 break;
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225 }
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226
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227 if (node->parent == NULL) {
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228 break;
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229 }
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230 }
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231
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232 return NGX_OK;
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233 }
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234
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235
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36
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236 uintptr_t
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237 ngx_radix32tree_find(ngx_radix_tree_t *tree, uint32_t key)
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34
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238 {
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239 uint32_t bit;
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240 uintptr_t value;
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241 ngx_radix_node_t *node;
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242
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243 bit = 0x80000000;
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244 value = NGX_RADIX_NO_VALUE;
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245 node = tree->root;
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246
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247 while (node) {
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248 if (node->value != NGX_RADIX_NO_VALUE) {
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249 value = node->value;
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250 }
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251
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252 if (key & bit) {
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253 node = node->right;
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254
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255 } else {
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256 node = node->left;
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257 }
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258
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259 bit >>= 1;
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260 }
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261
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262 return value;
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263 }
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264
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265
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36
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266 static void *
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267 ngx_radix_alloc(ngx_radix_tree_t *tree)
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34
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268 {
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269 char *p;
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270
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271 if (tree->free) {
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272 p = (char *) tree->free;
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273 tree->free = tree->free->right;
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274 return p;
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275 }
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276
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277 if (tree->size < sizeof(ngx_radix_node_t)) {
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404
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278 tree->start = ngx_pmemalign(tree->pool, ngx_pagesize, ngx_pagesize);
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50
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279 if (tree->start == NULL) {
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280 return NULL;
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281 }
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282
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283 tree->size = ngx_pagesize;
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284 }
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285
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286 p = tree->start;
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287 tree->start += sizeof(ngx_radix_node_t);
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288 tree->size -= sizeof(ngx_radix_node_t);
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289
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290 return p;
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291 }
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