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 |
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