1 | // |
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2 | // Lol Engine |
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3 | // |
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4 | // Copyright: (c) 2010-2013 Sam Hocevar <sam@hocevar.net> |
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5 | // This program is free software; you can redistribute it and/or |
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6 | // modify it under the terms of the Do What The Fuck You Want To |
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7 | // Public License, Version 2, as published by Sam Hocevar. See |
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8 | // http://www.wtfpl.net/ for more details. |
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9 | // |
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10 | |
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11 | #if defined HAVE_CONFIG_H |
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12 | # include "config.h" |
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13 | #endif |
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14 | |
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15 | #include "core.h" |
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16 | |
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17 | namespace lol |
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18 | { |
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19 | |
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20 | /* |
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21 | * Hash implementations |
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22 | */ |
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23 | |
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24 | static class HashData |
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25 | { |
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26 | public: |
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27 | HashData() |
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28 | { |
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29 | /* Initialise CRC32 table */ |
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30 | for (int i = 0; i < 256; i++) |
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31 | { |
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32 | uint32_t tmp = i; |
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33 | for (int j = 8; j--; ) |
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34 | tmp = (tmp >> 1) ^ ((tmp & 1) ? 0xedb88320 : 0); |
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35 | crc32_table[i] = tmp; |
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36 | } |
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37 | } |
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38 | |
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39 | uint32_t crc32_table[256]; |
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40 | } |
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41 | const data; |
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42 | |
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43 | /* |
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44 | * Helper hash functions |
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45 | */ |
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46 | |
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47 | static inline uint32_t Hash8(uint8_t x) |
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48 | { |
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49 | uint32_t ret = 0xffffffffu; |
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50 | ret = data.crc32_table[(uint8_t)(ret ^ x)] ^ (ret >> 8); |
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51 | return ret ^ 0xffffffffu; |
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52 | } |
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53 | |
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54 | static inline uint32_t Hash16(uint16_t x) |
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55 | { |
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56 | uint32_t ret = 0xffffffffu; |
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57 | ret = data.crc32_table[(uint8_t)(ret ^ x)] ^ (ret >> 8); |
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58 | ret = data.crc32_table[(uint8_t)(ret ^ (x >> 8))] ^ (ret >> 8); |
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59 | return ret ^ 0xffffffffu; |
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60 | } |
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61 | |
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62 | static inline uint32_t Hash32(uint32_t x) |
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63 | { |
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64 | uint32_t ret = 0xffffffffu; |
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65 | ret = data.crc32_table[(uint8_t)(ret ^ x)] ^ (ret >> 8); |
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66 | ret = data.crc32_table[(uint8_t)(ret ^ (x >> 8))] ^ (ret >> 8); |
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67 | ret = data.crc32_table[(uint8_t)(ret ^ (x >> 16))] ^ (ret >> 8); |
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68 | ret = data.crc32_table[(uint8_t)(ret ^ (x >> 24))] ^ (ret >> 8); |
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69 | return ret ^ 0xffffffffu; |
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70 | } |
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71 | |
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72 | static inline uint32_t Hash64(uint64_t x) |
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73 | { |
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74 | uint32_t ret = 0xffffffffu; |
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75 | ret = data.crc32_table[(uint8_t)(ret ^ x)] ^ (ret >> 8); |
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76 | ret = data.crc32_table[(uint8_t)(ret ^ (x >> 8))] ^ (ret >> 8); |
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77 | ret = data.crc32_table[(uint8_t)(ret ^ (x >> 16))] ^ (ret >> 8); |
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78 | ret = data.crc32_table[(uint8_t)(ret ^ (x >> 24))] ^ (ret >> 8); |
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79 | ret = data.crc32_table[(uint8_t)(ret ^ (x >> 32))] ^ (ret >> 8); |
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80 | ret = data.crc32_table[(uint8_t)(ret ^ (x >> 40))] ^ (ret >> 8); |
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81 | ret = data.crc32_table[(uint8_t)(ret ^ (x >> 48))] ^ (ret >> 8); |
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82 | ret = data.crc32_table[(uint8_t)(ret ^ (x >> 56))] ^ (ret >> 8); |
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83 | return ret ^ 0xffffffffu; |
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84 | } |
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85 | |
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86 | /* |
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87 | * Integer hash functions |
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88 | */ |
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89 | |
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90 | uint32_t Hash<int8_t>::operator ()(int8_t x) const |
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91 | { |
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92 | return Hash8((uint8_t)x); |
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93 | } |
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94 | |
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95 | uint32_t Hash<uint8_t>::operator ()(uint8_t x) const |
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96 | { |
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97 | return Hash8(x); |
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98 | } |
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99 | |
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100 | uint32_t Hash<int16_t>::operator ()(int16_t x) const |
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101 | { |
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102 | return Hash16((uint16_t)x); |
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103 | } |
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104 | |
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105 | uint32_t Hash<uint16_t>::operator ()(uint16_t x) const |
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106 | { |
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107 | return Hash16(x); |
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108 | } |
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109 | |
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110 | uint32_t Hash<int32_t>::operator ()(int32_t x) const |
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111 | { |
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112 | return Hash32((uint32_t)x); |
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113 | } |
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114 | |
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115 | uint32_t Hash<uint32_t>::operator ()(uint32_t x) const |
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116 | { |
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117 | return Hash32(x); |
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118 | } |
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119 | |
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120 | uint32_t Hash<int64_t>::operator ()(int64_t x) const |
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121 | { |
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122 | return Hash64((uint64_t)x); |
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123 | } |
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124 | |
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125 | uint32_t Hash<uint64_t>::operator ()(uint64_t x) const |
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126 | { |
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127 | return Hash64(x); |
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128 | } |
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129 | |
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130 | /* |
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131 | * Floating-point hash functions |
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132 | */ |
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133 | |
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134 | uint32_t Hash<half>::operator ()(half f) const |
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135 | { |
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136 | return Hash16(f.bits); |
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137 | } |
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138 | |
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139 | uint32_t Hash<float>::operator ()(float f) const |
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140 | { |
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141 | union { float tmp; uint32_t x; } u = { f }; |
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142 | return Hash32(u.x); |
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143 | } |
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144 | |
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145 | uint32_t Hash<double>::operator ()(double f) const |
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146 | { |
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147 | union { double tmp; uint64_t x; } u = { f }; |
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148 | return Hash64(u.x); |
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149 | } |
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150 | |
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151 | /* |
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152 | * String and array hash functions |
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153 | */ |
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154 | |
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155 | static uint32_t HashCharString(char const *s) |
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156 | { |
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157 | uint32_t ret = 0xffffffffu, ch; |
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158 | |
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159 | while ((ch = (uint8_t)*s++)) |
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160 | ret = data.crc32_table[(uint8_t)(ret ^ ch)] ^ (ret >> 8); |
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161 | |
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162 | return ret ^ 0xffffffffu; |
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163 | } |
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164 | |
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165 | uint32_t Hash<char const *>::operator ()(char const *s) const |
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166 | { |
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167 | return HashCharString(s); |
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168 | } |
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169 | |
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170 | uint32_t Hash<String>::operator ()(String const &s) const |
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171 | { |
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172 | return HashCharString(&s[0]); |
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173 | } |
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174 | |
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175 | } /* namespace lol */ |
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176 | |
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