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1 //----------------------------------------------------------------------------- |
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2 // boost detail/reference_content.hpp header file |
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3 // See http://www.boost.org for updates, documentation, and revision history. |
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4 //----------------------------------------------------------------------------- |
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5 // |
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6 // Copyright (c) 2003 |
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7 // Eric Friedman |
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8 // |
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9 // Distributed under the Boost Software License, Version 1.0. (See |
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10 // accompanying file LICENSE_1_0.txt or copy at |
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11 // http://www.boost.org/LICENSE_1_0.txt) |
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12 |
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13 #ifndef BOOST_DETAIL_REFERENCE_CONTENT_HPP |
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14 #define BOOST_DETAIL_REFERENCE_CONTENT_HPP |
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15 |
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16 #include "boost/config.hpp" |
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17 |
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18 #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) |
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19 # include "boost/mpl/bool.hpp" |
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20 # include "boost/type_traits/has_nothrow_copy.hpp" |
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21 #else |
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22 # include "boost/mpl/if.hpp" |
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23 # include "boost/type_traits/is_reference.hpp" |
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24 #endif |
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25 |
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26 #include "boost/mpl/void.hpp" |
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27 |
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28 namespace boost { |
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29 |
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30 namespace detail { |
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31 |
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32 /////////////////////////////////////////////////////////////////////////////// |
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33 // (detail) class template reference_content |
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34 // |
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35 // Non-Assignable wrapper for references. |
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36 // |
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37 template <typename RefT> |
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38 class reference_content |
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39 { |
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40 private: // representation |
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41 |
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42 RefT content_; |
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43 |
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44 public: // structors |
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45 |
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46 ~reference_content() |
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47 { |
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48 } |
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49 |
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50 reference_content(RefT r) |
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51 : content_( r ) |
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52 { |
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53 } |
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54 |
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55 reference_content(const reference_content& operand) |
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56 : content_( operand.content_ ) |
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57 { |
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58 } |
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59 |
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60 private: // non-Assignable |
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61 |
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62 reference_content& operator=(const reference_content&); |
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63 |
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64 public: // queries |
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65 |
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66 RefT get() const |
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67 { |
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68 return content_; |
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69 } |
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70 |
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71 }; |
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72 |
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73 /////////////////////////////////////////////////////////////////////////////// |
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74 // (detail) metafunction make_reference_content |
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75 // |
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76 // Wraps with reference_content if specified type is reference. |
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77 // |
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78 |
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79 template <typename T = mpl::void_> struct make_reference_content; |
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80 |
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81 #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) |
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82 |
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83 template <typename T> |
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84 struct make_reference_content |
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85 { |
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86 typedef T type; |
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87 }; |
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88 |
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89 template <typename T> |
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90 struct make_reference_content< T& > |
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91 { |
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92 typedef reference_content<T&> type; |
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93 }; |
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94 |
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95 #else // defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) |
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96 |
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97 template <typename T> |
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98 struct make_reference_content |
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99 : mpl::if_< |
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100 is_reference<T> |
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101 , reference_content<T> |
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102 , T |
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103 > |
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104 { |
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105 }; |
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106 |
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107 #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION workaround |
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108 |
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109 template <> |
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110 struct make_reference_content< mpl::void_ > |
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111 { |
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112 template <typename T> |
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113 struct apply |
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114 : make_reference_content<T> |
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115 { |
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116 }; |
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117 |
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118 typedef mpl::void_ type; |
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119 }; |
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120 |
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121 } // namespace detail |
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122 |
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123 /////////////////////////////////////////////////////////////////////////////// |
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124 // reference_content<T&> type traits specializations |
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125 // |
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126 |
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127 #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) |
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128 |
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129 template <typename T> |
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130 struct has_nothrow_copy< |
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131 ::boost::detail::reference_content< T& > |
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132 > |
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133 : mpl::true_ |
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134 { |
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135 }; |
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136 |
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137 #endif // !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) |
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138 |
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139 } // namespace boost |
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140 |
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141 #endif // BOOST_DETAIL_REFERENCE_CONTENT_HPP |