1 | |
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2 | // (C) Copyright Dave Abrahams, Steve Cleary, Beman Dawes, |
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3 | // Howard Hinnant and John Maddock 2000. |
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4 | // (C) Copyright Mat Marcus, Jesse Jones and Adobe Systems Inc 2001 |
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5 | |
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6 | // Use, modification and distribution are subject to the Boost Software License, |
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7 | // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
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8 | // http://www.boost.org/LICENSE_1_0.txt). |
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9 | // |
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10 | // See http://www.boost.org/libs/type_traits for most recent version including documentation. |
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11 | |
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12 | // Fixed is_pointer, is_reference, is_const, is_volatile, is_same, |
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13 | // is_member_pointer based on the Simulated Partial Specialization work |
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14 | // of Mat Marcus and Jesse Jones. See http://opensource.adobe.com or |
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15 | // http://groups.yahoo.com/group/boost/message/5441 |
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16 | // Some workarounds in here use ideas suggested from "Generic<Programming>: |
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17 | // Mappings between Types and Values" |
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18 | // by Andrei Alexandrescu (see http://www.cuj.com/experts/1810/alexandr.html). |
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19 | |
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20 | |
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21 | #ifndef BOOST_TT_IS_CONST_HPP_INCLUDED |
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22 | #define BOOST_TT_IS_CONST_HPP_INCLUDED |
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23 | |
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24 | #include <boost/config.hpp> |
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25 | #include <boost/detail/workaround.hpp> |
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26 | |
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27 | #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION |
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28 | # include <boost/type_traits/detail/cv_traits_impl.hpp> |
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29 | # ifdef __GNUC__ |
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30 | # include <boost/type_traits/is_reference.hpp> |
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31 | # endif |
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32 | # if BOOST_WORKAROUND(BOOST_MSVC, < 1400) |
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33 | # include <boost/type_traits/remove_bounds.hpp> |
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34 | # endif |
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35 | #else |
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36 | # include <boost/type_traits/is_reference.hpp> |
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37 | # include <boost/type_traits/is_array.hpp> |
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38 | # include <boost/type_traits/detail/yes_no_type.hpp> |
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39 | # include <boost/type_traits/detail/false_result.hpp> |
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40 | #endif |
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41 | |
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42 | // should be the last #include |
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43 | #include <boost/type_traits/detail/bool_trait_def.hpp> |
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44 | |
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45 | namespace boost { |
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46 | |
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47 | #if defined( __CODEGEARC__ ) |
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48 | |
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49 | BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_const,T,__is_const(T)) |
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50 | |
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51 | #elif !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) |
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52 | |
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53 | namespace detail{ |
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54 | // |
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55 | // We can't filter out rvalue_references at the same level as |
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56 | // references or we get ambiguities from msvc: |
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57 | // |
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58 | template <class T> |
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59 | struct is_const_rvalue_filter |
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60 | { |
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61 | #if BOOST_WORKAROUND(BOOST_MSVC, < 1400) |
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62 | BOOST_STATIC_CONSTANT(bool, value = ::boost::detail::cv_traits_imp<typename boost::remove_bounds<T>::type*>::is_const); |
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63 | #else |
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64 | BOOST_STATIC_CONSTANT(bool, value = ::boost::detail::cv_traits_imp<T*>::is_const); |
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65 | #endif |
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66 | }; |
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67 | #ifndef BOOST_NO_RVALUE_REFERENCES |
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68 | template <class T> |
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69 | struct is_const_rvalue_filter<T&&> |
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70 | { |
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71 | BOOST_STATIC_CONSTANT(bool, value = false); |
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72 | }; |
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73 | #endif |
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74 | } |
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75 | |
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76 | //* is a type T declared const - is_const<T> |
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77 | BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_const,T,::boost::detail::is_const_rvalue_filter<T>::value) |
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78 | BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_const,T&,false) |
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79 | |
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80 | #if defined(BOOST_ILLEGAL_CV_REFERENCES) |
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81 | // these are illegal specialisations; cv-qualifies applied to |
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82 | // references have no effect according to [8.3.2p1], |
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83 | // C++ Builder requires them though as it treats cv-qualified |
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84 | // references as distinct types... |
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85 | BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_const,T& const,false) |
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86 | BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_const,T& volatile,false) |
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87 | BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_const,T& const volatile,false) |
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88 | #endif |
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89 | |
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90 | #if defined(__GNUC__) && (__GNUC__ < 3) |
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91 | // special case for gcc where illegally cv-qualified reference types can be |
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92 | // generated in some corner cases: |
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93 | BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_const,T const,!(::boost::is_reference<T>::value)) |
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94 | BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_const,T volatile const,!(::boost::is_reference<T>::value)) |
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95 | #endif |
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96 | |
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97 | #else |
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98 | |
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99 | namespace detail { |
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100 | |
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101 | using ::boost::type_traits::yes_type; |
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102 | using ::boost::type_traits::no_type; |
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103 | |
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104 | yes_type is_const_tester(const volatile void*); |
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105 | no_type is_const_tester(volatile void *); |
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106 | |
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107 | template <bool is_ref, bool array> |
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108 | struct is_const_helper |
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109 | : ::boost::type_traits::false_result |
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110 | { |
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111 | }; |
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112 | |
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113 | template <> |
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114 | struct is_const_helper<false,false> |
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115 | { |
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116 | template <typename T> struct result_ |
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117 | { |
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118 | static T* t; |
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119 | BOOST_STATIC_CONSTANT(bool, value = ( |
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120 | sizeof(boost::detail::yes_type) == sizeof(boost::detail::is_const_tester(t)) |
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121 | )); |
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122 | }; |
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123 | }; |
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124 | |
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125 | template <> |
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126 | struct is_const_helper<false,true> |
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127 | { |
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128 | template <typename T> struct result_ |
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129 | { |
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130 | static T t; |
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131 | BOOST_STATIC_CONSTANT(bool, value = ( |
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132 | sizeof(boost::detail::yes_type) == sizeof(boost::detail::is_const_tester(&t)) |
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133 | )); |
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134 | }; |
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135 | }; |
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136 | |
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137 | template <typename T> |
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138 | struct is_const_impl |
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139 | : is_const_helper< |
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140 | is_reference<T>::value |
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141 | , is_array<T>::value |
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142 | >::template result_<T> |
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143 | { |
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144 | }; |
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145 | |
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146 | BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_const,void,false) |
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147 | #ifndef BOOST_NO_CV_VOID_SPECIALIZATIONS |
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148 | BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_const,void const,true) |
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149 | BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_const,void volatile,false) |
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150 | BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_const,void const volatile,true) |
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151 | #endif |
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152 | |
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153 | } // namespace detail |
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154 | |
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155 | //* is a type T declared const - is_const<T> |
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156 | BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_const,T,::boost::detail::is_const_impl<T>::value) |
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157 | |
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158 | #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION |
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159 | |
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160 | } // namespace boost |
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161 | |
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162 | #include <boost/type_traits/detail/bool_trait_undef.hpp> |
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163 | |
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164 | #endif // BOOST_TT_IS_CONST_HPP_INCLUDED |
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165 | |
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