1 | // See http://www.boost.org/libs/any for Documentation. |
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2 | |
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3 | #ifndef BOOST_ANY_INCLUDED |
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4 | #define BOOST_ANY_INCLUDED |
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5 | |
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6 | // what: variant type boost::any |
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7 | // who: contributed by Kevlin Henney, |
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8 | // with features contributed and bugs found by |
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9 | // Ed Brey, Mark Rodgers, Peter Dimov, and James Curran |
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10 | // when: July 2001 |
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11 | // where: tested with BCC 5.5, MSVC 6.0, and g++ 2.95 |
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12 | |
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13 | #include <algorithm> |
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14 | #include <typeinfo> |
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15 | |
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16 | #include "boost/config.hpp" |
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17 | #include <boost/type_traits/remove_reference.hpp> |
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18 | #include <boost/type_traits/is_reference.hpp> |
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19 | #include <boost/throw_exception.hpp> |
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20 | #include <boost/static_assert.hpp> |
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21 | |
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22 | // See boost/python/type_id.hpp |
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23 | // TODO: add BOOST_TYPEID_COMPARE_BY_NAME to config.hpp |
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24 | # if (defined(__GNUC__) && __GNUC__ >= 3) \ |
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25 | || defined(_AIX) \ |
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26 | || ( defined(__sgi) && defined(__host_mips)) \ |
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27 | || (defined(__hpux) && defined(__HP_aCC)) \ |
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28 | || (defined(linux) && defined(__INTEL_COMPILER) && defined(__ICC)) |
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29 | # define BOOST_AUX_ANY_TYPE_ID_NAME |
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30 | #include <cstring> |
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31 | # endif |
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32 | |
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33 | namespace boost |
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34 | { |
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35 | class any |
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36 | { |
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37 | public: // structors |
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38 | |
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39 | any() |
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40 | : content(0) |
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41 | { |
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42 | } |
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43 | |
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44 | template<typename ValueType> |
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45 | any(const ValueType & value) |
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46 | : content(new holder<ValueType>(value)) |
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47 | { |
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48 | } |
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49 | |
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50 | any(const any & other) |
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51 | : content(other.content ? other.content->clone() : 0) |
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52 | { |
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53 | } |
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54 | |
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55 | ~any() |
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56 | { |
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57 | delete content; |
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58 | } |
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59 | |
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60 | public: // modifiers |
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61 | |
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62 | any & swap(any & rhs) |
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63 | { |
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64 | std::swap(content, rhs.content); |
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65 | return *this; |
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66 | } |
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67 | |
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68 | template<typename ValueType> |
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69 | any & operator=(const ValueType & rhs) |
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70 | { |
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71 | any(rhs).swap(*this); |
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72 | return *this; |
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73 | } |
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74 | |
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75 | any & operator=(any rhs) |
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76 | { |
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77 | rhs.swap(*this); |
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78 | return *this; |
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79 | } |
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80 | |
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81 | public: // queries |
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82 | |
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83 | bool empty() const |
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84 | { |
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85 | return !content; |
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86 | } |
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87 | |
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88 | const std::type_info & type() const |
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89 | { |
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90 | return content ? content->type() : typeid(void); |
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91 | } |
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92 | |
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93 | #ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS |
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94 | private: // types |
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95 | #else |
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96 | public: // types (public so any_cast can be non-friend) |
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97 | #endif |
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98 | |
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99 | class placeholder |
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100 | { |
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101 | public: // structors |
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102 | |
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103 | virtual ~placeholder() |
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104 | { |
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105 | } |
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106 | |
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107 | public: // queries |
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108 | |
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109 | virtual const std::type_info & type() const = 0; |
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110 | |
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111 | virtual placeholder * clone() const = 0; |
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112 | |
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113 | }; |
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114 | |
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115 | template<typename ValueType> |
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116 | class holder : public placeholder |
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117 | { |
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118 | public: // structors |
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119 | |
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120 | holder(const ValueType & value) |
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121 | : held(value) |
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122 | { |
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123 | } |
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124 | |
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125 | public: // queries |
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126 | |
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127 | virtual const std::type_info & type() const |
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128 | { |
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129 | return typeid(ValueType); |
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130 | } |
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131 | |
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132 | virtual placeholder * clone() const |
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133 | { |
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134 | return new holder(held); |
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135 | } |
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136 | |
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137 | public: // representation |
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138 | |
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139 | ValueType held; |
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140 | |
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141 | private: // intentionally left unimplemented |
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142 | holder & operator=(const holder &); |
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143 | }; |
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144 | |
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145 | #ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS |
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146 | |
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147 | private: // representation |
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148 | |
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149 | template<typename ValueType> |
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150 | friend ValueType * any_cast(any *); |
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151 | |
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152 | template<typename ValueType> |
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153 | friend ValueType * unsafe_any_cast(any *); |
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154 | |
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155 | #else |
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156 | |
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157 | public: // representation (public so any_cast can be non-friend) |
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158 | |
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159 | #endif |
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160 | |
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161 | placeholder * content; |
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162 | |
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163 | }; |
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164 | |
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165 | class bad_any_cast : public std::bad_cast |
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166 | { |
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167 | public: |
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168 | virtual const char * what() const throw() |
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169 | { |
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170 | return "boost::bad_any_cast: " |
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171 | "failed conversion using boost::any_cast"; |
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172 | } |
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173 | }; |
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174 | |
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175 | template<typename ValueType> |
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176 | ValueType * any_cast(any * operand) |
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177 | { |
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178 | return operand && |
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179 | #ifdef BOOST_AUX_ANY_TYPE_ID_NAME |
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180 | std::strcmp(operand->type().name(), typeid(ValueType).name()) == 0 |
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181 | #else |
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182 | operand->type() == typeid(ValueType) |
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183 | #endif |
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184 | ? &static_cast<any::holder<ValueType> *>(operand->content)->held |
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185 | : 0; |
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186 | } |
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187 | |
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188 | template<typename ValueType> |
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189 | inline const ValueType * any_cast(const any * operand) |
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190 | { |
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191 | return any_cast<ValueType>(const_cast<any *>(operand)); |
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192 | } |
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193 | |
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194 | template<typename ValueType> |
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195 | ValueType any_cast(any & operand) |
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196 | { |
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197 | typedef BOOST_DEDUCED_TYPENAME remove_reference<ValueType>::type nonref; |
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198 | |
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199 | #ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION |
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200 | // If 'nonref' is still reference type, it means the user has not |
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201 | // specialized 'remove_reference'. |
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202 | |
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203 | // Please use BOOST_BROKEN_COMPILER_TYPE_TRAITS_SPECIALIZATION macro |
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204 | // to generate specialization of remove_reference for your class |
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205 | // See type traits library documentation for details |
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206 | BOOST_STATIC_ASSERT(!is_reference<nonref>::value); |
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207 | #endif |
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208 | |
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209 | nonref * result = any_cast<nonref>(&operand); |
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210 | if(!result) |
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211 | boost::throw_exception(bad_any_cast()); |
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212 | return *result; |
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213 | } |
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214 | |
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215 | template<typename ValueType> |
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216 | inline ValueType any_cast(const any & operand) |
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217 | { |
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218 | typedef BOOST_DEDUCED_TYPENAME remove_reference<ValueType>::type nonref; |
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219 | |
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220 | #ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION |
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221 | // The comment in the above version of 'any_cast' explains when this |
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222 | // assert is fired and what to do. |
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223 | BOOST_STATIC_ASSERT(!is_reference<nonref>::value); |
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224 | #endif |
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225 | |
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226 | return any_cast<const nonref &>(const_cast<any &>(operand)); |
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227 | } |
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228 | |
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229 | // Note: The "unsafe" versions of any_cast are not part of the |
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230 | // public interface and may be removed at any time. They are |
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231 | // required where we know what type is stored in the any and can't |
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232 | // use typeid() comparison, e.g., when our types may travel across |
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233 | // different shared libraries. |
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234 | template<typename ValueType> |
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235 | inline ValueType * unsafe_any_cast(any * operand) |
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236 | { |
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237 | return &static_cast<any::holder<ValueType> *>(operand->content)->held; |
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238 | } |
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239 | |
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240 | template<typename ValueType> |
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241 | inline const ValueType * unsafe_any_cast(const any * operand) |
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242 | { |
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243 | return unsafe_any_cast<ValueType>(const_cast<any *>(operand)); |
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244 | } |
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245 | } |
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246 | |
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247 | // Copyright Kevlin Henney, 2000, 2001, 2002. All rights reserved. |
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248 | // |
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249 | // Distributed under the Boost Software License, Version 1.0. (See |
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250 | // accompanying file LICENSE_1_0.txt or copy at |
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251 | // http://www.boost.org/LICENSE_1_0.txt) |
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252 | |
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253 | #endif |
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