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