1 | /* -*- C++ -*- |
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2 | * |
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3 | * This file is a part of LEMON, a generic C++ optimization library |
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4 | * |
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5 | * Copyright (C) 2003-2006 |
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6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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8 | * |
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9 | * Permission to use, modify and distribute this software is granted |
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10 | * provided that this copyright notice appears in all copies. For |
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11 | * precise terms see the accompanying LICENSE file. |
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12 | * |
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13 | * This software is provided "AS IS" with no warranty of any kind, |
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14 | * express or implied, and with no claim as to its suitability for any |
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15 | * purpose. |
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16 | * |
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17 | */ |
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18 | |
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19 | #ifndef LEMON_BITS_VARIANT_H |
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20 | #define LEMON_BITS_VARIANT_H |
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21 | |
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22 | #include <lemon/error.h> |
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23 | |
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24 | namespace lemon { |
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25 | |
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26 | template <bool left, bool right> |
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27 | struct CTOr { |
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28 | static const bool value = true; |
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29 | }; |
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30 | |
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31 | template <> |
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32 | struct CTOr<false, false> { |
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33 | static const bool value = false; |
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34 | }; |
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35 | |
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36 | template <bool left, bool right> |
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37 | struct CTAnd { |
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38 | static const bool value = false; |
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39 | }; |
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40 | |
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41 | template <> |
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42 | struct CTAnd<true, true> { |
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43 | static const bool value = true; |
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44 | }; |
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45 | |
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46 | template <int left, int right> |
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47 | struct CTEqual { |
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48 | static const bool value = false; |
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49 | }; |
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50 | |
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51 | template <int val> |
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52 | struct CTEqual<val, val> { |
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53 | static const bool value = true; |
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54 | }; |
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55 | |
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56 | |
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57 | template <int left, int right> |
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58 | struct CTLess { |
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59 | static const bool value = left < right; |
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60 | }; |
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61 | |
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62 | template <int left> |
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63 | struct CTLess<left, 0> { |
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64 | static const bool value = false; |
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65 | }; |
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66 | |
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67 | template <int right> |
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68 | struct CTLess<0, right> { |
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69 | static const bool value = true; |
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70 | }; |
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71 | |
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72 | template <> |
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73 | struct CTLess<0, 0> { |
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74 | static const bool value = false; |
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75 | }; |
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76 | |
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77 | template <> |
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78 | struct CTLess<1, 1> { |
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79 | static const bool value = false; |
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80 | }; |
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81 | |
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82 | template <bool less, int left, int right> |
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83 | struct CTMaxImpl { |
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84 | static const int value = left; |
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85 | }; |
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86 | |
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87 | template <int left, int right> |
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88 | struct CTMaxImpl<true, left, right> { |
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89 | static const int value = right; |
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90 | }; |
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91 | |
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92 | template <int left, int right> |
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93 | struct CTMax { |
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94 | static const int value = |
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95 | CTMaxImpl<CTLess<left, right>::value, left, right>::value; |
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96 | }; |
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97 | |
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98 | |
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99 | /// \brief Simple Variant type with two type |
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100 | /// |
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101 | /// Simple Variant type with two type |
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102 | template <typename _First, typename _Second> |
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103 | class BiVariant { |
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104 | public: |
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105 | |
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106 | typedef _First First; |
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107 | typedef _Second Second; |
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108 | |
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109 | struct WrongStateError : public lemon::LogicError { |
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110 | public: |
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111 | virtual const char* what() const throw() { |
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112 | return "lemon::BiVariant::WrongStateError"; |
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113 | } |
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114 | }; |
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115 | |
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116 | BiVariant() { |
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117 | flag = true; |
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118 | new(reinterpret_cast<First*>(data)) First(); |
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119 | } |
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120 | |
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121 | BiVariant(const First& first) { |
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122 | flag = true; |
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123 | new(reinterpret_cast<First*>(data)) First(first); |
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124 | } |
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125 | |
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126 | BiVariant(const Second& second) { |
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127 | flag = false; |
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128 | new(reinterpret_cast<Second*>(data)) Second(second); |
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129 | } |
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130 | |
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131 | BiVariant(const BiVariant& bivariant) { |
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132 | flag = bivariant.flag; |
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133 | if (flag) { |
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134 | new(reinterpret_cast<First*>(data)) First(bivariant.first()); |
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135 | } else { |
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136 | new(reinterpret_cast<Second*>(data)) Second(bivariant.second()); |
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137 | } |
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138 | } |
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139 | |
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140 | ~BiVariant() { |
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141 | destroy(); |
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142 | } |
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143 | |
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144 | BiVariant& setFirst() { |
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145 | destroy(); |
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146 | flag = true; |
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147 | new(reinterpret_cast<First*>(data)) First(); |
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148 | return *this; |
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149 | } |
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150 | |
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151 | BiVariant& setFirst(const First& first) { |
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152 | destroy(); |
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153 | flag = true; |
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154 | new(reinterpret_cast<First*>(data)) First(first); |
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155 | return *this; |
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156 | } |
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157 | |
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158 | BiVariant& setSecond() { |
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159 | destroy(); |
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160 | flag = false; |
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161 | new(reinterpret_cast<Second*>(data)) Second(); |
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162 | return *this; |
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163 | } |
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164 | |
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165 | BiVariant& setSecond(const Second& second) { |
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166 | destroy(); |
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167 | flag = false; |
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168 | new(reinterpret_cast<Second*>(data)) Second(second); |
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169 | return *this; |
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170 | } |
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171 | |
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172 | BiVariant& operator=(const First& first) { |
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173 | return setFirst(first); |
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174 | } |
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175 | |
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176 | BiVariant& operator=(const Second& second) { |
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177 | return setSecond(second); |
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178 | } |
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179 | |
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180 | |
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181 | BiVariant& operator=(const BiVariant& bivariant) { |
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182 | if (this == &bivariant) return *this; |
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183 | destroy(); |
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184 | flag = bivariant.flag; |
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185 | if (flag) { |
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186 | new(reinterpret_cast<First*>(data)) First(bivariant.first()); |
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187 | } else { |
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188 | new(reinterpret_cast<Second*>(data)) Second(bivariant.second()); |
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189 | } |
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190 | return *this; |
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191 | } |
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192 | |
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193 | First& first() { |
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194 | LEMON_ASSERT(flag, WrongStateError()); |
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195 | return *reinterpret_cast<First*>(data); |
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196 | } |
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197 | |
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198 | const First& first() const { |
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199 | LEMON_ASSERT(flag, WrongStateError()); |
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200 | return *reinterpret_cast<const First*>(data); |
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201 | } |
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202 | |
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203 | operator First&() { return first(); } |
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204 | operator const First&() const { return first(); } |
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205 | |
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206 | Second& second() { |
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207 | LEMON_ASSERT(!flag, WrongStateError()); |
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208 | return *reinterpret_cast<Second*>(data); |
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209 | } |
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210 | |
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211 | const Second& second() const { |
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212 | LEMON_ASSERT(!flag, WrongStateError()); |
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213 | return *reinterpret_cast<const Second*>(data); |
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214 | } |
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215 | |
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216 | operator Second&() { return second(); } |
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217 | operator const Second&() const { return second(); } |
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218 | |
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219 | bool firstState() const { return flag; } |
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220 | bool secondState() const { return !flag; } |
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221 | |
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222 | private: |
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223 | |
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224 | void destroy() { |
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225 | if (flag) { |
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226 | reinterpret_cast<First*>(data)->~First(); |
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227 | } else { |
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228 | reinterpret_cast<Second*>(data)->~Second(); |
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229 | } |
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230 | } |
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231 | |
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232 | char data[CTMax<sizeof(First), sizeof(Second)>::value]; |
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233 | bool flag; |
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234 | }; |
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235 | |
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236 | } |
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237 | |
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238 | |
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239 | #endif |
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