507
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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 ngx_int_t
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509
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12 ngx_hash_init(ngx_hash_t *hash, ngx_pool_t *pool, void *names, ngx_uint_t nelts)
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507
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13 {
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14 u_char *p;
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509
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15 ngx_str_t *name, *bucket;
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16 ngx_uint_t i, n, key, size, best, *test, buckets, min_buckets;
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17
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18 if (nelts == 0) {
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19 for (name = (ngx_str_t *) names;
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20 name->len;
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21 name = (ngx_str_t *) ((char *) name + hash->bucket_size))
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22 {
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23 nelts++;
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24 }
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25 }
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507
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26
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27 test = ngx_alloc(hash->max_size * sizeof(ngx_uint_t), pool->log);
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28 if (test == NULL) {
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29 return NGX_ERROR;
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30 }
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31
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32 min_buckets = hash->bucket_limit + 1;
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33
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34 #if (NGX_SUPPRESS_WARN)
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35 best = 0;
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36 #endif
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37
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38 for (size = 1; size < hash->max_size; size++) {
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39
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40 buckets = 0;
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41
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42 for (i = 0; i < size; i++) {
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43 test[i] = 0;
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44 }
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45
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509
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46 for (n = 0, name = (ngx_str_t *) names;
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47 n < nelts;
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48 n++, name = (ngx_str_t *) ((char *) name + hash->bucket_size))
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49 {
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50 key = 0;
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51
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509
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52 for (i = 0; i < name->len; i++) {
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53 key += ngx_tolower(name->data[i]);
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54 }
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55
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56 key %= size;
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57
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58 if (test[key] == hash->bucket_limit) {
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59 break;
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60 }
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61
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62 test[key]++;
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63
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64 if (buckets < test[key]) {
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65 buckets = test[key];
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66 }
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67 }
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68
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509
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69 if (n == nelts) {
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70 if (min_buckets > buckets) {
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71 min_buckets = buckets;
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72 best = size;
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73 }
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74
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75 if (hash->bucket_limit == 1) {
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76 break;
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77 }
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78 }
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79 }
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80
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81 if (min_buckets == hash->bucket_limit + 1) {
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82 ngx_log_error(NGX_LOG_EMERG, pool->log, 0,
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83 "could not build the %s hash, you should increase "
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84 "either %s_size: %i or %s_bucket_limit: %i",
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85 hash->name, hash->name, hash->max_size,
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86 hash->name, hash->bucket_limit);
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87 ngx_free(test);
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88 return NGX_ERROR;
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89 }
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90
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91 hash->buckets = ngx_pcalloc(pool, best * hash->bucket_size);
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92 if (hash->buckets == NULL) {
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93 ngx_free(test);
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94 return NGX_ERROR;
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95 }
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96
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97 if (hash->bucket_limit != 1) {
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98
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99 for (i = 0; i < best; i++) {
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100 test[i] = 0;
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101 }
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102
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509
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103 for (n = 0, name = (ngx_str_t *) names;
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104 n < nelts;
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105 n++, name = (ngx_str_t *) ((char *) name + hash->bucket_size))
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106 {
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107 key = 0;
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108
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109 for (i = 0; i < name->len; i++) {
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110 key += ngx_tolower(name->data[i]);
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111 }
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112
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113 key %= best;
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114
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115 test[key]++;
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116 }
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117
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118 for (i = 0; i < best; i++) {
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119 if (test[i] == 0) {
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120 continue;
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121 }
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122
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123 bucket = ngx_palloc(pool, test[i] * hash->bucket_size);
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124 if (bucket == NULL) {
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125 ngx_free(test);
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126 return NGX_ERROR;
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127 }
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128
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129 hash->buckets[i] = bucket;
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130 bucket->len = 0;
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131 }
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132 }
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133
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509
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134 for (n = 0, name = (ngx_str_t *) names;
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135 n < nelts;
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136 n++, name = (ngx_str_t *) ((char *) name + hash->bucket_size))
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137 {
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138 key = 0;
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139
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509
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140 for (i = 0; i < name->len; i++) {
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141 key += ngx_tolower(name->data[i]);
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142 }
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143
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144 key %= best;
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145
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146 if (hash->bucket_limit == 1) {
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147 p = (u_char *) hash->buckets + key * hash->bucket_size;
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148 ngx_memcpy(p, name, hash->bucket_size);
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149 continue;
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150 }
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151
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152 for (bucket = hash->buckets[key];
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153 bucket->len;
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154 bucket = (ngx_str_t *) ((char *) bucket + hash->bucket_size))
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155 {
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156 bucket->len &= 0x7fffffff;
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157 }
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158
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159 ngx_memcpy(bucket, name, hash->bucket_size);
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160 bucket->len |= 0x80000000;
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161 }
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162
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163 ngx_free(test);
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164
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165 hash->hash_size = best;
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166 hash->min_buckets = min_buckets;
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167
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168 return NGX_OK;
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169 }
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