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 | // This file contains a modified version of the enable_if library from BOOST. |
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20 | // See the appropriate copyright notice below. |
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21 | |
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22 | // Boost enable_if library |
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23 | |
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24 | // Copyright 2003 © The Trustees of Indiana University. |
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25 | |
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26 | // Use, modification, and distribution is subject to the Boost Software |
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27 | // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
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28 | // http://www.boost.org/LICENSE_1_0.txt) |
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29 | |
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30 | // Authors: Jaakko Järvi (jajarvi at osl.iu.edu) |
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31 | // Jeremiah Willcock (jewillco at osl.iu.edu) |
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32 | // Andrew Lumsdaine (lums at osl.iu.edu) |
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33 | |
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34 | |
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35 | #ifndef LEMON_BITS_UTILITY_H |
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36 | #define LEMON_BITS_UTILITY_H |
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37 | |
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38 | #include <lemon/error.h> |
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39 | |
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40 | ///\file |
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41 | ///\brief Miscellaneous basic utilities |
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42 | /// |
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43 | ///\todo Please rethink the organisation of the basic files like this. |
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44 | ///E.g. this file might be merged with invalid.h. |
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45 | |
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46 | |
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47 | namespace lemon |
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48 | { |
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49 | |
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50 | /// Basic type for defining "tags". A "YES" condition for \c enable_if. |
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51 | |
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52 | /// Basic type for defining "tags". A "YES" condition for \c enable_if. |
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53 | /// |
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54 | ///\sa False |
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55 | /// |
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56 | /// \todo This should go to a separate "basic_types.h" (or something) |
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57 | /// file. |
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58 | struct True { |
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59 | ///\e |
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60 | static const bool value = true; |
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61 | }; |
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62 | |
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63 | /// Basic type for defining "tags". A "NO" condition for \c enable_if. |
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64 | |
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65 | /// Basic type for defining "tags". A "NO" condition for \c enable_if. |
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66 | /// |
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67 | ///\sa True |
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68 | struct False { |
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69 | ///\e |
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70 | static const bool value = false; |
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71 | }; |
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72 | |
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73 | |
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74 | class InvalidType { |
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75 | private: |
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76 | InvalidType(); |
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77 | }; |
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78 | |
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79 | template <bool left, bool right> |
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80 | struct CTOr { |
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81 | static const bool value = true; |
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82 | }; |
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83 | |
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84 | template <> |
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85 | struct CTOr<false, false> { |
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86 | static const bool value = false; |
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87 | }; |
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88 | |
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89 | template <bool left, bool right> |
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90 | struct CTAnd { |
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91 | static const bool value = false; |
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92 | }; |
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93 | |
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94 | template <> |
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95 | struct CTAnd<true, true> { |
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96 | static const bool value = true; |
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97 | }; |
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98 | |
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99 | template <int left, int right> |
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100 | struct CTEqual { |
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101 | static const bool value = false; |
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102 | }; |
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103 | |
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104 | template <int val> |
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105 | struct CTEqual<val, val> { |
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106 | static const bool value = true; |
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107 | }; |
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108 | |
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109 | |
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110 | template <int left, int right> |
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111 | struct CTLess { |
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112 | static const bool value = left < right; |
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113 | }; |
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114 | |
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115 | template <int left> |
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116 | struct CTLess<left, 0> { |
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117 | static const bool value = false; |
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118 | }; |
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119 | |
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120 | template <int right> |
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121 | struct CTLess<0, right> { |
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122 | static const bool value = true; |
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123 | }; |
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124 | |
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125 | template <> |
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126 | struct CTLess<0, 0> { |
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127 | static const bool value = false; |
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128 | }; |
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129 | |
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130 | template <> |
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131 | struct CTLess<1, 1> { |
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132 | static const bool value = false; |
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133 | }; |
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134 | |
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135 | template <bool less, int left, int right> |
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136 | struct CTMaxImpl { |
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137 | static const int value = left; |
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138 | }; |
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139 | |
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140 | template <int left, int right> |
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141 | struct CTMaxImpl<true, left, right> { |
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142 | static const int value = right; |
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143 | }; |
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144 | |
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145 | template <int left, int right> |
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146 | struct CTMax { |
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147 | static const int value = |
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148 | CTMaxImpl<CTLess<left, right>::value, left, right>::value; |
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149 | }; |
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150 | |
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151 | |
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152 | /// \brief Simple Variant type with two type |
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153 | /// |
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154 | /// Simple Variant type with two type |
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155 | template <typename _First, typename _Second> |
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156 | class BiVariant { |
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157 | public: |
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158 | |
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159 | typedef _First First; |
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160 | typedef _Second Second; |
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161 | |
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162 | struct WrongStateError : public lemon::LogicError { |
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163 | public: |
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164 | virtual const char* what() const throw() { |
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165 | return "lemon::BiVariant::WrongStateError"; |
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166 | } |
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167 | }; |
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168 | |
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169 | BiVariant() { |
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170 | flag = true; |
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171 | new(reinterpret_cast<First*>(data)) First(); |
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172 | } |
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173 | |
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174 | BiVariant(const First& first) { |
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175 | flag = true; |
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176 | new(reinterpret_cast<First*>(data)) First(first); |
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177 | } |
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178 | |
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179 | BiVariant(const Second& second) { |
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180 | flag = false; |
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181 | new(reinterpret_cast<Second*>(data)) Second(second); |
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182 | } |
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183 | |
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184 | BiVariant(const BiVariant& bivariant) { |
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185 | flag = bivariant.flag; |
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186 | if (flag) { |
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187 | new(reinterpret_cast<First*>(data)) First(bivariant.first()); |
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188 | } else { |
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189 | new(reinterpret_cast<Second*>(data)) Second(bivariant.second()); |
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190 | } |
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191 | } |
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192 | |
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193 | ~BiVariant() { |
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194 | destroy(); |
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195 | } |
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196 | |
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197 | BiVariant& setFirst() { |
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198 | destroy(); |
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199 | flag = true; |
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200 | new(reinterpret_cast<First*>(data)) First(); |
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201 | return *this; |
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202 | } |
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203 | |
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204 | BiVariant& setFirst(const First& first) { |
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205 | destroy(); |
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206 | flag = true; |
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207 | new(reinterpret_cast<First*>(data)) First(first); |
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208 | return *this; |
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209 | } |
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210 | |
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211 | BiVariant& setSecond() { |
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212 | destroy(); |
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213 | flag = false; |
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214 | new(reinterpret_cast<Second*>(data)) Second(); |
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215 | return *this; |
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216 | } |
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217 | |
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218 | BiVariant& setSecond(const Second& second) { |
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219 | destroy(); |
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220 | flag = false; |
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221 | new(reinterpret_cast<Second*>(data)) Second(second); |
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222 | return *this; |
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223 | } |
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224 | |
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225 | BiVariant& operator=(const First& first) { |
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226 | return setFirst(first); |
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227 | } |
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228 | |
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229 | BiVariant& operator=(const Second& second) { |
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230 | return setSecond(second); |
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231 | } |
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232 | |
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233 | |
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234 | BiVariant& operator=(const BiVariant& bivariant) { |
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235 | if (this == &bivariant) return *this; |
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236 | destroy(); |
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237 | flag = bivariant.flag; |
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238 | if (flag) { |
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239 | new(reinterpret_cast<First*>(data)) First(bivariant.first()); |
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240 | } else { |
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241 | new(reinterpret_cast<Second*>(data)) Second(bivariant.second()); |
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242 | } |
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243 | return *this; |
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244 | } |
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245 | |
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246 | First& first() { |
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247 | LEMON_ASSERT(flag, WrongStateError()); |
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248 | return *reinterpret_cast<First*>(data); |
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249 | } |
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250 | |
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251 | const First& first() const { |
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252 | LEMON_ASSERT(flag, WrongStateError()); |
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253 | return *reinterpret_cast<const First*>(data); |
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254 | } |
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255 | |
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256 | operator First&() { return first(); } |
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257 | operator const First&() const { return first(); } |
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258 | |
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259 | Second& second() { |
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260 | LEMON_ASSERT(!flag, WrongStateError()); |
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261 | return *reinterpret_cast<Second*>(data); |
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262 | } |
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263 | |
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264 | const Second& second() const { |
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265 | LEMON_ASSERT(!flag, WrongStateError()); |
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266 | return *reinterpret_cast<const Second*>(data); |
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267 | } |
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268 | |
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269 | operator Second&() { return second(); } |
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270 | operator const Second&() const { return second(); } |
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271 | |
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272 | bool firstState() const { return flag; } |
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273 | bool secondState() const { return !flag; } |
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274 | |
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275 | private: |
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276 | |
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277 | void destroy() { |
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278 | if (flag) { |
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279 | reinterpret_cast<First*>(data)->~First(); |
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280 | } else { |
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281 | reinterpret_cast<Second*>(data)->~Second(); |
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282 | } |
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283 | } |
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284 | |
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285 | char data[CTMax<sizeof(First), sizeof(Second)>::value]; |
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286 | bool flag; |
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287 | }; |
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288 | |
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289 | template <typename T> |
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290 | struct Wrap { |
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291 | const T &value; |
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292 | Wrap(const T &t) : value(t) {} |
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293 | }; |
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294 | |
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295 | /**************** dummy class to avoid ambiguity ****************/ |
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296 | |
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297 | template<int T> struct dummy { dummy(int) {} }; |
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298 | |
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299 | /**************** enable_if from BOOST ****************/ |
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300 | |
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301 | template <bool B, class T = void> |
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302 | struct enable_if_c { |
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303 | typedef T type; |
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304 | }; |
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305 | |
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306 | template <class T> |
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307 | struct enable_if_c<false, T> {}; |
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308 | |
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309 | template <class Cond, class T = void> |
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310 | struct enable_if : public enable_if_c<Cond::value, T> {}; |
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311 | |
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312 | template <bool B, class T> |
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313 | struct lazy_enable_if_c { |
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314 | typedef typename T::type type; |
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315 | }; |
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316 | |
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317 | template <class T> |
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318 | struct lazy_enable_if_c<false, T> {}; |
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319 | |
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320 | template <class Cond, class T> |
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321 | struct lazy_enable_if : public lazy_enable_if_c<Cond::value, T> {}; |
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322 | |
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323 | |
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324 | template <bool B, class T = void> |
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325 | struct disable_if_c { |
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326 | typedef T type; |
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327 | }; |
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328 | |
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329 | template <class T> |
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330 | struct disable_if_c<true, T> {}; |
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331 | |
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332 | template <class Cond, class T = void> |
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333 | struct disable_if : public disable_if_c<Cond::value, T> {}; |
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334 | |
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335 | template <bool B, class T> |
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336 | struct lazy_disable_if_c { |
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337 | typedef typename T::type type; |
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338 | }; |
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339 | |
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340 | template <class T> |
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341 | struct lazy_disable_if_c<true, T> {}; |
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342 | |
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343 | template <class Cond, class T> |
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344 | struct lazy_disable_if : public lazy_disable_if_c<Cond::value, T> {}; |
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345 | |
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346 | } // namespace lemon |
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347 | |
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348 | #endif |
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