1 | /* Copyright 2003-2006 Joaquín M López Muñoz. |
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2 | * Distributed under the Boost Software License, Version 1.0. |
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3 | * (See accompanying file LICENSE_1_0.txt or copy at |
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4 | * http://www.boost.org/LICENSE_1_0.txt) |
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5 | * |
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6 | * See http://www.boost.org/libs/multi_index for library home page. |
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7 | */ |
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8 | |
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9 | #ifndef BOOST_MULTI_INDEX_MEMBER_HPP |
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10 | #define BOOST_MULTI_INDEX_MEMBER_HPP |
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11 | |
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12 | #if defined(_MSC_VER)&&(_MSC_VER>=1200) |
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13 | #pragma once |
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14 | #endif |
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15 | |
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16 | #include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */ |
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17 | #include <boost/mpl/if.hpp> |
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18 | #include <boost/type_traits/is_const.hpp> |
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19 | #include <boost/utility/enable_if.hpp> |
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20 | #include <cstddef> |
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21 | |
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22 | #if !defined(BOOST_NO_SFINAE) |
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23 | #include <boost/type_traits/is_convertible.hpp> |
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24 | #endif |
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25 | |
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26 | namespace boost{ |
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27 | |
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28 | template<class T> class reference_wrapper; /* fwd decl. */ |
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29 | |
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30 | namespace multi_index{ |
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31 | |
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32 | namespace detail{ |
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33 | |
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34 | /* member is a read/write key extractor for accessing a given |
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35 | * member of a class. |
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36 | * Additionally, member is overloaded to support referece_wrappers |
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37 | * of T and "chained pointers" to T's. By chained pointer to T we mean |
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38 | * a type P such that, given a p of Type P |
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39 | * *...n...*x is convertible to T&, for some n>=1. |
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40 | * Examples of chained pointers are raw and smart pointers, iterators and |
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41 | * arbitrary combinations of these (vg. T** or auto_ptr<T*>.) |
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42 | */ |
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43 | |
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44 | /* NB. Some overloads of operator() have an extra dummy parameter int=0. |
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45 | * This disambiguator serves several purposes: |
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46 | * - Without it, MSVC++ 6.0 incorrectly regards some overloads as |
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47 | * specializations of a previous member function template. |
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48 | * - MSVC++ 6.0/7.0 seem to incorrectly treat some different memfuns |
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49 | * as if they have the same signature. |
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50 | * - If remove_const is broken due to lack of PTS, int=0 avoids the |
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51 | * declaration of memfuns with identical signature. |
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52 | */ |
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53 | |
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54 | template<class Class,typename Type,Type Class::*PtrToMember> |
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55 | struct const_member_base |
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56 | { |
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57 | typedef Type result_type; |
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58 | |
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59 | template<typename ChainedPtr> |
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60 | |
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61 | #if !defined(BOOST_NO_SFINAE) |
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62 | typename disable_if< |
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63 | is_convertible<const ChainedPtr&,const Class&>,Type&>::type |
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64 | #else |
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65 | Type& |
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66 | #endif |
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67 | |
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68 | operator()(const ChainedPtr& x)const |
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69 | { |
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70 | return operator()(*x); |
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71 | } |
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72 | |
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73 | Type& operator()(const Class& x)const |
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74 | { |
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75 | return x.*PtrToMember; |
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76 | } |
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77 | |
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78 | Type& operator()(const reference_wrapper<const Class>& x)const |
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79 | { |
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80 | return operator()(x.get()); |
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81 | } |
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82 | |
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83 | Type& operator()(const reference_wrapper<Class>& x,int=0)const |
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84 | { |
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85 | return operator()(x.get()); |
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86 | } |
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87 | }; |
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88 | |
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89 | template<class Class,typename Type,Type Class::*PtrToMember> |
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90 | struct non_const_member_base |
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91 | { |
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92 | typedef Type result_type; |
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93 | |
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94 | template<typename ChainedPtr> |
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95 | |
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96 | #if !defined(BOOST_NO_SFINAE) |
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97 | typename disable_if< |
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98 | is_convertible<const ChainedPtr&,const Class&>,Type&>::type |
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99 | #else |
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100 | Type& |
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101 | #endif |
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102 | |
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103 | operator()(const ChainedPtr& x)const |
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104 | { |
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105 | return operator()(*x); |
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106 | } |
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107 | |
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108 | const Type& operator()(const Class& x,int=0)const |
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109 | { |
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110 | return x.*PtrToMember; |
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111 | } |
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112 | |
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113 | Type& operator()(Class& x)const |
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114 | { |
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115 | return x.*PtrToMember; |
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116 | } |
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117 | |
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118 | const Type& operator()(const reference_wrapper<const Class>& x,int=0)const |
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119 | { |
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120 | return operator()(x.get()); |
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121 | } |
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122 | |
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123 | Type& operator()(const reference_wrapper<Class>& x)const |
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124 | { |
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125 | return operator()(x.get()); |
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126 | } |
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127 | }; |
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128 | |
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129 | } /* namespace multi_index::detail */ |
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130 | |
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131 | template<class Class,typename Type,Type Class::*PtrToMember> |
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132 | struct member: |
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133 | mpl::if_c< |
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134 | is_const<Type>::value, |
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135 | detail::const_member_base<Class,Type,PtrToMember>, |
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136 | detail::non_const_member_base<Class,Type,PtrToMember> |
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137 | >::type |
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138 | { |
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139 | }; |
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140 | |
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141 | namespace detail{ |
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142 | |
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143 | /* MSVC++ 6.0 does not support properly pointers to members as |
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144 | * non-type template arguments, as reported in |
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145 | * http://support.microsoft.com/default.aspx?scid=kb;EN-US;249045 |
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146 | * A similar problem (though not identical) is shown by MSVC++ 7.0. |
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147 | * We provide an alternative to member<> accepting offsets instead |
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148 | * of pointers to members. This happens to work even for non-POD |
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149 | * types (although the standard forbids use of offsetof on these), |
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150 | * so it serves as a workaround in this compiler for all practical |
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151 | * purposes. |
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152 | * Surprisingly enough, other compilers, like Intel C++ 7.0/7.1 and |
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153 | * Visual Age 6.0, have similar bugs. This replacement of member<> |
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154 | * can be used for them too. |
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155 | */ |
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156 | |
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157 | template<class Class,typename Type,std::size_t OffsetOfMember> |
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158 | struct const_member_offset_base |
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159 | { |
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160 | typedef Type result_type; |
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161 | |
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162 | template<typename ChainedPtr> |
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163 | |
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164 | #if !defined(BOOST_NO_SFINAE) |
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165 | typename disable_if< |
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166 | is_convertible<const ChainedPtr&,const Class&>,Type&>::type |
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167 | #else |
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168 | Type& |
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169 | #endif |
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170 | |
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171 | operator()(const ChainedPtr& x)const |
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172 | { |
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173 | return operator()(*x); |
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174 | } |
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175 | |
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176 | Type& operator()(const Class& x)const |
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177 | { |
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178 | return *static_cast<const Type*>( |
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179 | static_cast<const void*>( |
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180 | static_cast<const char*>( |
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181 | static_cast<const void *>(&x))+OffsetOfMember)); |
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182 | } |
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183 | |
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184 | Type& operator()(const reference_wrapper<const Class>& x)const |
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185 | { |
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186 | return operator()(x.get()); |
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187 | } |
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188 | |
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189 | Type& operator()(const reference_wrapper<Class>& x,int=0)const |
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190 | { |
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191 | return operator()(x.get()); |
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192 | } |
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193 | }; |
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194 | |
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195 | template<class Class,typename Type,std::size_t OffsetOfMember> |
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196 | struct non_const_member_offset_base |
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197 | { |
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198 | typedef Type result_type; |
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199 | |
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200 | template<typename ChainedPtr> |
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201 | |
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202 | #if !defined(BOOST_NO_SFINAE) |
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203 | typename disable_if< |
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204 | is_convertible<const ChainedPtr&,const Class&>,Type&>::type |
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205 | #else |
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206 | Type& |
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207 | #endif |
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208 | |
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209 | operator()(const ChainedPtr& x)const |
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210 | { |
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211 | return operator()(*x); |
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212 | } |
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213 | |
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214 | const Type& operator()(const Class& x,int=0)const |
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215 | { |
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216 | return *static_cast<const Type*>( |
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217 | static_cast<const void*>( |
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218 | static_cast<const char*>( |
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219 | static_cast<const void *>(&x))+OffsetOfMember)); |
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220 | } |
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221 | |
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222 | Type& operator()(Class& x)const |
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223 | { |
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224 | return *static_cast<Type*>( |
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225 | static_cast<void*>( |
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226 | static_cast<char*>(static_cast<void *>(&x))+OffsetOfMember)); |
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227 | } |
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228 | |
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229 | const Type& operator()(const reference_wrapper<const Class>& x,int=0)const |
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230 | { |
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231 | return operator()(x.get()); |
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232 | } |
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233 | |
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234 | Type& operator()(const reference_wrapper<Class>& x)const |
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235 | { |
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236 | return operator()(x.get()); |
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237 | } |
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238 | }; |
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239 | |
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240 | } /* namespace multi_index::detail */ |
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241 | |
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242 | template<class Class,typename Type,std::size_t OffsetOfMember> |
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243 | struct member_offset: |
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244 | mpl::if_c< |
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245 | is_const<Type>::value, |
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246 | detail::const_member_offset_base<Class,Type,OffsetOfMember>, |
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247 | detail::non_const_member_offset_base<Class,Type,OffsetOfMember> |
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248 | >::type |
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249 | { |
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250 | }; |
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251 | |
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252 | /* BOOST_MULTI_INDEX_MEMBER resolves to member in the normal cases, |
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253 | * and to member_offset as a workaround in those defective compilers for |
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254 | * which BOOST_NO_POINTER_TO_MEMBER_TEMPLATE_PARAMETERS is defined. |
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255 | */ |
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256 | |
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257 | #if defined(BOOST_NO_POINTER_TO_MEMBER_TEMPLATE_PARAMETERS) |
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258 | #define BOOST_MULTI_INDEX_MEMBER(Class,Type,MemberName) \ |
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259 | ::boost::multi_index::member_offset< Class,Type,offsetof(Class,MemberName) > |
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260 | #else |
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261 | #define BOOST_MULTI_INDEX_MEMBER(Class,Type,MemberName) \ |
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262 | ::boost::multi_index::member< Class,Type,&Class::MemberName > |
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263 | #endif |
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264 | |
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265 | } /* namespace multi_index */ |
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266 | |
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267 | } /* namespace boost */ |
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268 | |
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269 | #endif |
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