1 | // (C) Copyright David Abrahams 2002. |
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2 | // (C) Copyright Jeremy Siek 2002. |
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3 | // (C) Copyright Thomas Witt 2002. |
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4 | // Distributed under the Boost Software License, Version 1.0. (See |
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5 | // accompanying file LICENSE_1_0.txt or copy at |
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6 | // http://www.boost.org/LICENSE_1_0.txt) |
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7 | #ifndef BOOST_ITERATOR_FACADE_23022003THW_HPP |
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8 | #define BOOST_ITERATOR_FACADE_23022003THW_HPP |
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9 | |
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10 | #include <boost/iterator.hpp> |
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11 | #include <boost/iterator/interoperable.hpp> |
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12 | #include <boost/iterator/iterator_traits.hpp> |
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13 | |
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14 | #include <boost/iterator/detail/facade_iterator_category.hpp> |
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15 | #include <boost/iterator/detail/enable_if.hpp> |
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16 | |
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17 | #include <boost/implicit_cast.hpp> |
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18 | #include <boost/static_assert.hpp> |
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19 | |
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20 | #include <boost/type_traits/is_same.hpp> |
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21 | #include <boost/type_traits/add_const.hpp> |
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22 | #include <boost/type_traits/add_pointer.hpp> |
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23 | #include <boost/type_traits/remove_const.hpp> |
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24 | #include <boost/type_traits/remove_reference.hpp> |
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25 | #include <boost/type_traits/is_convertible.hpp> |
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26 | #include <boost/type_traits/is_pod.hpp> |
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27 | |
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28 | #include <boost/mpl/eval_if.hpp> |
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29 | #include <boost/mpl/if.hpp> |
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30 | #include <boost/mpl/or.hpp> |
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31 | #include <boost/mpl/and.hpp> |
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32 | #include <boost/mpl/not.hpp> |
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33 | #include <boost/mpl/always.hpp> |
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34 | #include <boost/mpl/apply.hpp> |
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35 | #include <boost/mpl/identity.hpp> |
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36 | |
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37 | #include <boost/iterator/detail/config_def.hpp> // this goes last |
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38 | |
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39 | namespace boost |
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40 | { |
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41 | // This forward declaration is required for the friend declaration |
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42 | // in iterator_core_access |
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43 | template <class I, class V, class TC, class R, class D> class iterator_facade; |
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44 | |
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45 | namespace detail |
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46 | { |
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47 | // A binary metafunction class that always returns bool. VC6 |
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48 | // ICEs on mpl::always<bool>, probably because of the default |
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49 | // parameters. |
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50 | struct always_bool2 |
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51 | { |
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52 | template <class T, class U> |
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53 | struct apply |
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54 | { |
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55 | typedef bool type; |
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56 | }; |
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57 | }; |
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58 | |
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59 | // |
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60 | // enable if for use in operator implementation. |
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61 | // |
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62 | template < |
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63 | class Facade1 |
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64 | , class Facade2 |
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65 | , class Return |
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66 | > |
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67 | struct enable_if_interoperable |
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68 | #if BOOST_WORKAROUND(BOOST_MSVC, <= 1300) |
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69 | { |
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70 | typedef typename mpl::if_< |
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71 | mpl::or_< |
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72 | is_convertible<Facade1, Facade2> |
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73 | , is_convertible<Facade2, Facade1> |
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74 | > |
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75 | , Return |
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76 | , int[3] |
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77 | >::type type; |
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78 | }; |
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79 | #else |
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80 | : ::boost::iterators::enable_if< |
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81 | mpl::or_< |
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82 | is_convertible<Facade1, Facade2> |
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83 | , is_convertible<Facade2, Facade1> |
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84 | > |
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85 | , Return |
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86 | > |
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87 | {}; |
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88 | #endif |
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89 | |
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90 | // |
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91 | // Generates associated types for an iterator_facade with the |
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92 | // given parameters. |
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93 | // |
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94 | template < |
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95 | class ValueParam |
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96 | , class CategoryOrTraversal |
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97 | , class Reference |
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98 | , class Difference |
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99 | > |
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100 | struct iterator_facade_types |
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101 | { |
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102 | typedef typename facade_iterator_category< |
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103 | CategoryOrTraversal, ValueParam, Reference |
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104 | >::type iterator_category; |
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105 | |
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106 | typedef typename remove_const<ValueParam>::type value_type; |
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107 | |
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108 | typedef typename mpl::eval_if< |
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109 | boost::detail::iterator_writability_disabled<ValueParam,Reference> |
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110 | , add_pointer<const value_type> |
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111 | , add_pointer<value_type> |
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112 | >::type pointer; |
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113 | |
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114 | # if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) \ |
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115 | && (BOOST_WORKAROUND(_STLPORT_VERSION, BOOST_TESTED_AT(0x452)) \ |
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116 | || BOOST_WORKAROUND(BOOST_DINKUMWARE_STDLIB, BOOST_TESTED_AT(310))) \ |
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117 | || BOOST_WORKAROUND(BOOST_RWSTD_VER, BOOST_TESTED_AT(0x20101)) \ |
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118 | || BOOST_WORKAROUND(BOOST_DINKUMWARE_STDLIB, <= 310) |
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119 | |
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120 | // To interoperate with some broken library/compiler |
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121 | // combinations, user-defined iterators must be derived from |
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122 | // std::iterator. It is possible to implement a standard |
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123 | // library for broken compilers without this limitation. |
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124 | # define BOOST_ITERATOR_FACADE_NEEDS_ITERATOR_BASE 1 |
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125 | |
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126 | typedef |
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127 | iterator<iterator_category, value_type, Difference, pointer, Reference> |
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128 | base; |
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129 | # endif |
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130 | }; |
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131 | |
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132 | // iterators whose dereference operators reference the same value |
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133 | // for all iterators into the same sequence (like many input |
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134 | // iterators) need help with their postfix ++: the referenced |
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135 | // value must be read and stored away before the increment occurs |
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136 | // so that *a++ yields the originally referenced element and not |
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137 | // the next one. |
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138 | template <class Iterator> |
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139 | class postfix_increment_proxy |
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140 | { |
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141 | typedef typename iterator_value<Iterator>::type value_type; |
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142 | public: |
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143 | explicit postfix_increment_proxy(Iterator const& x) |
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144 | : stored_value(*x) |
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145 | {} |
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146 | |
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147 | // Returning a mutable reference allows nonsense like |
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148 | // (*r++).mutate(), but it imposes fewer assumptions about the |
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149 | // behavior of the value_type. In particular, recall taht |
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150 | // (*r).mutate() is legal if operator* returns by value. |
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151 | value_type& |
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152 | operator*() const |
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153 | { |
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154 | return this->stored_value; |
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155 | } |
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156 | private: |
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157 | mutable value_type stored_value; |
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158 | }; |
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159 | |
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160 | // |
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161 | // In general, we can't determine that such an iterator isn't |
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162 | // writable -- we also need to store a copy of the old iterator so |
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163 | // that it can be written into. |
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164 | template <class Iterator> |
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165 | class writable_postfix_increment_proxy |
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166 | { |
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167 | typedef typename iterator_value<Iterator>::type value_type; |
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168 | public: |
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169 | explicit writable_postfix_increment_proxy(Iterator const& x) |
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170 | : stored_value(*x) |
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171 | , stored_iterator(x) |
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172 | {} |
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173 | |
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174 | // Dereferencing must return a proxy so that both *r++ = o and |
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175 | // value_type(*r++) can work. In this case, *r is the same as |
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176 | // *r++, and the conversion operator below is used to ensure |
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177 | // readability. |
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178 | writable_postfix_increment_proxy const& |
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179 | operator*() const |
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180 | { |
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181 | return *this; |
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182 | } |
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183 | |
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184 | // Provides readability of *r++ |
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185 | operator value_type&() const |
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186 | { |
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187 | return stored_value; |
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188 | } |
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189 | |
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190 | // Provides writability of *r++ |
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191 | template <class T> |
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192 | T const& operator=(T const& x) const |
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193 | { |
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194 | *this->stored_iterator = x; |
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195 | return x; |
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196 | } |
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197 | |
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198 | // This overload just in case only non-const objects are writable |
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199 | template <class T> |
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200 | T& operator=(T& x) const |
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201 | { |
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202 | *this->stored_iterator = x; |
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203 | return x; |
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204 | } |
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205 | |
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206 | // Provides X(r++) |
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207 | operator Iterator const&() const |
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208 | { |
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209 | return stored_iterator; |
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210 | } |
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211 | |
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212 | private: |
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213 | mutable value_type stored_value; |
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214 | Iterator stored_iterator; |
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215 | }; |
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216 | |
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217 | # ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION |
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218 | |
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219 | template <class Reference, class Value> |
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220 | struct is_non_proxy_reference_impl |
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221 | { |
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222 | static Reference r; |
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223 | |
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224 | template <class R> |
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225 | static typename mpl::if_< |
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226 | is_convertible< |
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227 | R const volatile* |
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228 | , Value const volatile* |
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229 | > |
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230 | , char[1] |
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231 | , char[2] |
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232 | >::type& helper(R const&); |
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233 | |
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234 | BOOST_STATIC_CONSTANT(bool, value = sizeof(helper(r)) == 1); |
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235 | }; |
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236 | |
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237 | template <class Reference, class Value> |
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238 | struct is_non_proxy_reference |
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239 | : mpl::bool_< |
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240 | is_non_proxy_reference_impl<Reference, Value>::value |
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241 | > |
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242 | {}; |
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243 | # else |
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244 | template <class Reference, class Value> |
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245 | struct is_non_proxy_reference |
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246 | : is_convertible< |
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247 | typename remove_reference<Reference>::type |
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248 | const volatile* |
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249 | , Value const volatile* |
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250 | > |
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251 | {}; |
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252 | # endif |
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253 | |
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254 | // A metafunction to choose the result type of postfix ++ |
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255 | // |
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256 | // Because the C++98 input iterator requirements say that *r++ has |
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257 | // type T (value_type), implementations of some standard |
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258 | // algorithms like lexicographical_compare may use constructions |
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259 | // like: |
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260 | // |
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261 | // *r++ < *s++ |
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262 | // |
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263 | // If *r++ returns a proxy (as required if r is writable but not |
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264 | // multipass), this sort of expression will fail unless the proxy |
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265 | // supports the operator<. Since there are any number of such |
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266 | // operations, we're not going to try to support them. Therefore, |
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267 | // even if r++ returns a proxy, *r++ will only return a proxy if |
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268 | // *r also returns a proxy. |
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269 | template <class Iterator, class Value, class Reference, class CategoryOrTraversal> |
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270 | struct postfix_increment_result |
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271 | : mpl::eval_if< |
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272 | mpl::and_< |
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273 | // A proxy is only needed for readable iterators |
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274 | is_convertible<Reference,Value const&> |
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275 | |
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276 | // No multipass iterator can have values that disappear |
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277 | // before positions can be re-visited |
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278 | , mpl::not_< |
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279 | is_convertible< |
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280 | typename iterator_category_to_traversal<CategoryOrTraversal>::type |
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281 | , forward_traversal_tag |
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282 | > |
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283 | > |
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284 | > |
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285 | , mpl::if_< |
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286 | is_non_proxy_reference<Reference,Value> |
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287 | , postfix_increment_proxy<Iterator> |
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288 | , writable_postfix_increment_proxy<Iterator> |
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289 | > |
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290 | , mpl::identity<Iterator> |
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291 | > |
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292 | {}; |
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293 | |
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294 | // operator->() needs special support for input iterators to strictly meet the |
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295 | // standard's requirements. If *i is not a reference type, we must still |
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296 | // produce a lvalue to which a pointer can be formed. We do that by |
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297 | // returning an instantiation of this special proxy class template. |
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298 | template <class T> |
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299 | struct operator_arrow_proxy |
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300 | { |
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301 | operator_arrow_proxy(T const* px) : m_value(*px) {} |
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302 | T* operator->() const { return &m_value; } |
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303 | // This function is needed for MWCW and BCC, which won't call operator-> |
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304 | // again automatically per 13.3.1.2 para 8 |
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305 | operator T*() const { return &m_value; } |
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306 | mutable T m_value; |
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307 | }; |
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308 | |
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309 | // A metafunction that gets the result type for operator->. Also |
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310 | // has a static function make() which builds the result from a |
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311 | // Reference |
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312 | template <class ValueType, class Reference, class Pointer> |
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313 | struct operator_arrow_result |
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314 | { |
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315 | // CWPro8.3 won't accept "operator_arrow_result::type", and we |
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316 | // need that type below, so metafunction forwarding would be a |
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317 | // losing proposition here. |
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318 | typedef typename mpl::if_< |
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319 | is_reference<Reference> |
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320 | , Pointer |
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321 | , operator_arrow_proxy<ValueType> |
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322 | >::type type; |
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323 | |
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324 | static type make(Reference x) |
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325 | { |
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326 | return implicit_cast<type>(&x); |
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327 | } |
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328 | }; |
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329 | |
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330 | # if BOOST_WORKAROUND(BOOST_MSVC, < 1300) |
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331 | // Deal with ETI |
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332 | template<> |
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333 | struct operator_arrow_result<int, int, int> |
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334 | { |
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335 | typedef int type; |
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336 | }; |
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337 | # endif |
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338 | |
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339 | // A proxy return type for operator[], needed to deal with |
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340 | // iterators that may invalidate referents upon destruction. |
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341 | // Consider the temporary iterator in *(a + n) |
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342 | template <class Iterator> |
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343 | class operator_brackets_proxy |
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344 | { |
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345 | // Iterator is actually an iterator_facade, so we do not have to |
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346 | // go through iterator_traits to access the traits. |
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347 | typedef typename Iterator::reference reference; |
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348 | typedef typename Iterator::value_type value_type; |
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349 | |
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350 | public: |
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351 | operator_brackets_proxy(Iterator const& iter) |
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352 | : m_iter(iter) |
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353 | {} |
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354 | |
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355 | operator reference() const |
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356 | { |
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357 | return *m_iter; |
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358 | } |
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359 | |
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360 | operator_brackets_proxy& operator=(value_type const& val) |
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361 | { |
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362 | *m_iter = val; |
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363 | return *this; |
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364 | } |
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365 | |
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366 | private: |
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367 | Iterator m_iter; |
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368 | }; |
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369 | |
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370 | // A metafunction that determines whether operator[] must return a |
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371 | // proxy, or whether it can simply return a copy of the value_type. |
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372 | template <class ValueType, class Reference> |
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373 | struct use_operator_brackets_proxy |
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374 | : mpl::not_< |
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375 | mpl::and_< |
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376 | // Really we want an is_copy_constructible trait here, |
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377 | // but is_POD will have to suffice in the meantime. |
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378 | boost::is_POD<ValueType> |
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379 | , iterator_writability_disabled<ValueType,Reference> |
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380 | > |
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381 | > |
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382 | {}; |
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383 | |
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384 | template <class Iterator, class Value, class Reference> |
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385 | struct operator_brackets_result |
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386 | { |
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387 | typedef typename mpl::if_< |
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388 | use_operator_brackets_proxy<Value,Reference> |
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389 | , operator_brackets_proxy<Iterator> |
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390 | , Value |
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391 | >::type type; |
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392 | }; |
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393 | |
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394 | template <class Iterator> |
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395 | operator_brackets_proxy<Iterator> make_operator_brackets_result(Iterator const& iter, mpl::true_) |
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396 | { |
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397 | return operator_brackets_proxy<Iterator>(iter); |
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398 | } |
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399 | |
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400 | template <class Iterator> |
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401 | typename Iterator::value_type make_operator_brackets_result(Iterator const& iter, mpl::false_) |
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402 | { |
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403 | return *iter; |
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404 | } |
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405 | |
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406 | struct choose_difference_type |
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407 | { |
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408 | template <class I1, class I2> |
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409 | struct apply |
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410 | : |
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411 | # ifdef BOOST_NO_ONE_WAY_ITERATOR_INTEROP |
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412 | iterator_difference<I1> |
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413 | # elif BOOST_WORKAROUND(BOOST_MSVC, < 1300) |
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414 | mpl::if_< |
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415 | is_convertible<I2,I1> |
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416 | , typename I1::difference_type |
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417 | , typename I2::difference_type |
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418 | > |
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419 | # else |
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420 | mpl::eval_if< |
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421 | is_convertible<I2,I1> |
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422 | , iterator_difference<I1> |
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423 | , iterator_difference<I2> |
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424 | > |
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425 | # endif |
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426 | {}; |
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427 | |
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428 | }; |
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429 | } // namespace detail |
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430 | |
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431 | |
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432 | // Macros which describe the declarations of binary operators |
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433 | # ifdef BOOST_NO_STRICT_ITERATOR_INTEROPERABILITY |
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434 | # define BOOST_ITERATOR_FACADE_INTEROP_HEAD(prefix, op, result_type) \ |
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435 | template < \ |
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436 | class Derived1, class V1, class TC1, class Reference1, class Difference1 \ |
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437 | , class Derived2, class V2, class TC2, class Reference2, class Difference2 \ |
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438 | > \ |
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439 | prefix typename mpl::apply2<result_type,Derived1,Derived2>::type \ |
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440 | operator op( \ |
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441 | iterator_facade<Derived1, V1, TC1, Reference1, Difference1> const& lhs \ |
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442 | , iterator_facade<Derived2, V2, TC2, Reference2, Difference2> const& rhs) |
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443 | # else |
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444 | # define BOOST_ITERATOR_FACADE_INTEROP_HEAD(prefix, op, result_type) \ |
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445 | template < \ |
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446 | class Derived1, class V1, class TC1, class Reference1, class Difference1 \ |
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447 | , class Derived2, class V2, class TC2, class Reference2, class Difference2 \ |
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448 | > \ |
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449 | prefix typename boost::detail::enable_if_interoperable< \ |
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450 | Derived1, Derived2 \ |
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451 | , typename mpl::apply2<result_type,Derived1,Derived2>::type \ |
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452 | >::type \ |
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453 | operator op( \ |
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454 | iterator_facade<Derived1, V1, TC1, Reference1, Difference1> const& lhs \ |
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455 | , iterator_facade<Derived2, V2, TC2, Reference2, Difference2> const& rhs) |
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456 | # endif |
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457 | |
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458 | # define BOOST_ITERATOR_FACADE_PLUS_HEAD(prefix,args) \ |
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459 | template <class Derived, class V, class TC, class R, class D> \ |
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460 | prefix Derived operator+ args |
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461 | |
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462 | // |
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463 | // Helper class for granting access to the iterator core interface. |
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464 | // |
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465 | // The simple core interface is used by iterator_facade. The core |
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466 | // interface of a user/library defined iterator type should not be made public |
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467 | // so that it does not clutter the public interface. Instead iterator_core_access |
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468 | // should be made friend so that iterator_facade can access the core |
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469 | // interface through iterator_core_access. |
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470 | // |
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471 | class iterator_core_access |
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472 | { |
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473 | # if defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS) |
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474 | // Tasteless as this may seem, making all members public allows member templates |
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475 | // to work in the absence of member template friends. |
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476 | public: |
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477 | # else |
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478 | |
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479 | template <class I, class V, class TC, class R, class D> friend class iterator_facade; |
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480 | |
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481 | # define BOOST_ITERATOR_FACADE_RELATION(op) \ |
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482 | BOOST_ITERATOR_FACADE_INTEROP_HEAD(friend,op, boost::detail::always_bool2); |
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483 | |
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484 | BOOST_ITERATOR_FACADE_RELATION(==) |
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485 | BOOST_ITERATOR_FACADE_RELATION(!=) |
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486 | |
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487 | BOOST_ITERATOR_FACADE_RELATION(<) |
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488 | BOOST_ITERATOR_FACADE_RELATION(>) |
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489 | BOOST_ITERATOR_FACADE_RELATION(<=) |
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490 | BOOST_ITERATOR_FACADE_RELATION(>=) |
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491 | # undef BOOST_ITERATOR_FACADE_RELATION |
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492 | |
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493 | BOOST_ITERATOR_FACADE_INTEROP_HEAD( |
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494 | friend, -, boost::detail::choose_difference_type) |
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495 | ; |
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496 | |
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497 | BOOST_ITERATOR_FACADE_PLUS_HEAD( |
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498 | friend inline |
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499 | , (iterator_facade<Derived, V, TC, R, D> const& |
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500 | , typename Derived::difference_type) |
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501 | ) |
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502 | ; |
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503 | |
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504 | BOOST_ITERATOR_FACADE_PLUS_HEAD( |
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505 | friend inline |
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506 | , (typename Derived::difference_type |
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507 | , iterator_facade<Derived, V, TC, R, D> const&) |
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508 | ) |
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509 | ; |
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510 | |
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511 | # endif |
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512 | |
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513 | template <class Facade> |
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514 | static typename Facade::reference dereference(Facade const& f) |
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515 | { |
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516 | return f.dereference(); |
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517 | } |
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518 | |
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519 | template <class Facade> |
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520 | static void increment(Facade& f) |
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521 | { |
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522 | f.increment(); |
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523 | } |
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524 | |
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525 | template <class Facade> |
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526 | static void decrement(Facade& f) |
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527 | { |
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528 | f.decrement(); |
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529 | } |
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530 | |
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531 | template <class Facade1, class Facade2> |
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532 | static bool equal(Facade1 const& f1, Facade2 const& f2, mpl::true_) |
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533 | { |
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534 | return f1.equal(f2); |
---|
535 | } |
---|
536 | |
---|
537 | template <class Facade1, class Facade2> |
---|
538 | static bool equal(Facade1 const& f1, Facade2 const& f2, mpl::false_) |
---|
539 | { |
---|
540 | return f2.equal(f1); |
---|
541 | } |
---|
542 | |
---|
543 | template <class Facade> |
---|
544 | static void advance(Facade& f, typename Facade::difference_type n) |
---|
545 | { |
---|
546 | f.advance(n); |
---|
547 | } |
---|
548 | |
---|
549 | template <class Facade1, class Facade2> |
---|
550 | static typename Facade1::difference_type distance_from( |
---|
551 | Facade1 const& f1, Facade2 const& f2, mpl::true_) |
---|
552 | { |
---|
553 | return -f1.distance_to(f2); |
---|
554 | } |
---|
555 | |
---|
556 | template <class Facade1, class Facade2> |
---|
557 | static typename Facade2::difference_type distance_from( |
---|
558 | Facade1 const& f1, Facade2 const& f2, mpl::false_) |
---|
559 | { |
---|
560 | return f2.distance_to(f1); |
---|
561 | } |
---|
562 | |
---|
563 | // |
---|
564 | // Curiously Recurring Template interface. |
---|
565 | // |
---|
566 | template <class I, class V, class TC, class R, class D> |
---|
567 | static I& derived(iterator_facade<I,V,TC,R,D>& facade) |
---|
568 | { |
---|
569 | return *static_cast<I*>(&facade); |
---|
570 | } |
---|
571 | |
---|
572 | template <class I, class V, class TC, class R, class D> |
---|
573 | static I const& derived(iterator_facade<I,V,TC,R,D> const& facade) |
---|
574 | { |
---|
575 | return *static_cast<I const*>(&facade); |
---|
576 | } |
---|
577 | |
---|
578 | private: |
---|
579 | // objects of this class are useless |
---|
580 | iterator_core_access(); //undefined |
---|
581 | }; |
---|
582 | |
---|
583 | // |
---|
584 | // iterator_facade - use as a public base class for defining new |
---|
585 | // standard-conforming iterators. |
---|
586 | // |
---|
587 | template < |
---|
588 | class Derived // The derived iterator type being constructed |
---|
589 | , class Value |
---|
590 | , class CategoryOrTraversal |
---|
591 | , class Reference = Value& |
---|
592 | , class Difference = std::ptrdiff_t |
---|
593 | > |
---|
594 | class iterator_facade |
---|
595 | # ifdef BOOST_ITERATOR_FACADE_NEEDS_ITERATOR_BASE |
---|
596 | : public boost::detail::iterator_facade_types< |
---|
597 | Value, CategoryOrTraversal, Reference, Difference |
---|
598 | >::base |
---|
599 | # undef BOOST_ITERATOR_FACADE_NEEDS_ITERATOR_BASE |
---|
600 | # endif |
---|
601 | { |
---|
602 | private: |
---|
603 | // |
---|
604 | // Curiously Recurring Template interface. |
---|
605 | // |
---|
606 | Derived& derived() |
---|
607 | { |
---|
608 | return *static_cast<Derived*>(this); |
---|
609 | } |
---|
610 | |
---|
611 | Derived const& derived() const |
---|
612 | { |
---|
613 | return *static_cast<Derived const*>(this); |
---|
614 | } |
---|
615 | |
---|
616 | typedef boost::detail::iterator_facade_types< |
---|
617 | Value, CategoryOrTraversal, Reference, Difference |
---|
618 | > associated_types; |
---|
619 | |
---|
620 | protected: |
---|
621 | // For use by derived classes |
---|
622 | typedef iterator_facade<Derived,Value,CategoryOrTraversal,Reference,Difference> iterator_facade_; |
---|
623 | |
---|
624 | public: |
---|
625 | |
---|
626 | typedef typename associated_types::value_type value_type; |
---|
627 | typedef Reference reference; |
---|
628 | typedef Difference difference_type; |
---|
629 | typedef typename associated_types::pointer pointer; |
---|
630 | typedef typename associated_types::iterator_category iterator_category; |
---|
631 | |
---|
632 | reference operator*() const |
---|
633 | { |
---|
634 | return iterator_core_access::dereference(this->derived()); |
---|
635 | } |
---|
636 | |
---|
637 | typename boost::detail::operator_arrow_result< |
---|
638 | value_type |
---|
639 | , reference |
---|
640 | , pointer |
---|
641 | >::type |
---|
642 | operator->() const |
---|
643 | { |
---|
644 | return boost::detail::operator_arrow_result< |
---|
645 | value_type |
---|
646 | , reference |
---|
647 | , pointer |
---|
648 | >::make(*this->derived()); |
---|
649 | } |
---|
650 | |
---|
651 | typename boost::detail::operator_brackets_result<Derived,Value,reference>::type |
---|
652 | operator[](difference_type n) const |
---|
653 | { |
---|
654 | typedef boost::detail::use_operator_brackets_proxy<Value,Reference> use_proxy; |
---|
655 | |
---|
656 | return boost::detail::make_operator_brackets_result<Derived>( |
---|
657 | this->derived() + n |
---|
658 | , use_proxy() |
---|
659 | ); |
---|
660 | } |
---|
661 | |
---|
662 | Derived& operator++() |
---|
663 | { |
---|
664 | iterator_core_access::increment(this->derived()); |
---|
665 | return this->derived(); |
---|
666 | } |
---|
667 | |
---|
668 | # if BOOST_WORKAROUND(BOOST_MSVC, < 1300) |
---|
669 | typename boost::detail::postfix_increment_result<Derived,Value,Reference,CategoryOrTraversal>::type |
---|
670 | operator++(int) |
---|
671 | { |
---|
672 | typename boost::detail::postfix_increment_result<Derived,Value,Reference,CategoryOrTraversal>::type |
---|
673 | tmp(this->derived()); |
---|
674 | ++*this; |
---|
675 | return tmp; |
---|
676 | } |
---|
677 | # endif |
---|
678 | |
---|
679 | Derived& operator--() |
---|
680 | { |
---|
681 | iterator_core_access::decrement(this->derived()); |
---|
682 | return this->derived(); |
---|
683 | } |
---|
684 | |
---|
685 | Derived operator--(int) |
---|
686 | { |
---|
687 | Derived tmp(this->derived()); |
---|
688 | --*this; |
---|
689 | return tmp; |
---|
690 | } |
---|
691 | |
---|
692 | Derived& operator+=(difference_type n) |
---|
693 | { |
---|
694 | iterator_core_access::advance(this->derived(), n); |
---|
695 | return this->derived(); |
---|
696 | } |
---|
697 | |
---|
698 | Derived& operator-=(difference_type n) |
---|
699 | { |
---|
700 | iterator_core_access::advance(this->derived(), -n); |
---|
701 | return this->derived(); |
---|
702 | } |
---|
703 | |
---|
704 | Derived operator-(difference_type x) const |
---|
705 | { |
---|
706 | Derived result(this->derived()); |
---|
707 | return result -= x; |
---|
708 | } |
---|
709 | |
---|
710 | # if BOOST_WORKAROUND(BOOST_MSVC, < 1300) |
---|
711 | // There appears to be a bug which trashes the data of classes |
---|
712 | // derived from iterator_facade when they are assigned unless we |
---|
713 | // define this assignment operator. This bug is only revealed |
---|
714 | // (so far) in STLPort debug mode, but it's clearly a codegen |
---|
715 | // problem so we apply the workaround for all MSVC6. |
---|
716 | iterator_facade& operator=(iterator_facade const&) |
---|
717 | { |
---|
718 | return *this; |
---|
719 | } |
---|
720 | # endif |
---|
721 | }; |
---|
722 | |
---|
723 | # if !BOOST_WORKAROUND(BOOST_MSVC, < 1300) |
---|
724 | template <class I, class V, class TC, class R, class D> |
---|
725 | inline typename boost::detail::postfix_increment_result<I,V,R,TC>::type |
---|
726 | operator++( |
---|
727 | iterator_facade<I,V,TC,R,D>& i |
---|
728 | , int |
---|
729 | ) |
---|
730 | { |
---|
731 | typename boost::detail::postfix_increment_result<I,V,R,TC>::type |
---|
732 | tmp(*static_cast<I*>(&i)); |
---|
733 | |
---|
734 | ++i; |
---|
735 | |
---|
736 | return tmp; |
---|
737 | } |
---|
738 | # endif |
---|
739 | |
---|
740 | |
---|
741 | // |
---|
742 | // Comparison operator implementation. The library supplied operators |
---|
743 | // enables the user to provide fully interoperable constant/mutable |
---|
744 | // iterator types. I.e. the library provides all operators |
---|
745 | // for all mutable/constant iterator combinations. |
---|
746 | // |
---|
747 | // Note though that this kind of interoperability for constant/mutable |
---|
748 | // iterators is not required by the standard for container iterators. |
---|
749 | // All the standard asks for is a conversion mutable -> constant. |
---|
750 | // Most standard library implementations nowadays provide fully interoperable |
---|
751 | // iterator implementations, but there are still heavily used implementations |
---|
752 | // that do not provide them. (Actually it's even worse, they do not provide |
---|
753 | // them for only a few iterators.) |
---|
754 | // |
---|
755 | // ?? Maybe a BOOST_ITERATOR_NO_FULL_INTEROPERABILITY macro should |
---|
756 | // enable the user to turn off mixed type operators |
---|
757 | // |
---|
758 | // The library takes care to provide only the right operator overloads. |
---|
759 | // I.e. |
---|
760 | // |
---|
761 | // bool operator==(Iterator, Iterator); |
---|
762 | // bool operator==(ConstIterator, Iterator); |
---|
763 | // bool operator==(Iterator, ConstIterator); |
---|
764 | // bool operator==(ConstIterator, ConstIterator); |
---|
765 | // |
---|
766 | // ... |
---|
767 | // |
---|
768 | // In order to do so it uses c++ idioms that are not yet widely supported |
---|
769 | // by current compiler releases. The library is designed to degrade gracefully |
---|
770 | // in the face of compiler deficiencies. In general compiler |
---|
771 | // deficiencies result in less strict error checking and more obscure |
---|
772 | // error messages, functionality is not affected. |
---|
773 | // |
---|
774 | // For full operation compiler support for "Substitution Failure Is Not An Error" |
---|
775 | // (aka. enable_if) and boost::is_convertible is required. |
---|
776 | // |
---|
777 | // The following problems occur if support is lacking. |
---|
778 | // |
---|
779 | // Pseudo code |
---|
780 | // |
---|
781 | // --------------- |
---|
782 | // AdaptorA<Iterator1> a1; |
---|
783 | // AdaptorA<Iterator2> a2; |
---|
784 | // |
---|
785 | // // This will result in a no such overload error in full operation |
---|
786 | // // If enable_if or is_convertible is not supported |
---|
787 | // // The instantiation will fail with an error hopefully indicating that |
---|
788 | // // there is no operator== for Iterator1, Iterator2 |
---|
789 | // // The same will happen if no enable_if is used to remove |
---|
790 | // // false overloads from the templated conversion constructor |
---|
791 | // // of AdaptorA. |
---|
792 | // |
---|
793 | // a1 == a2; |
---|
794 | // ---------------- |
---|
795 | // |
---|
796 | // AdaptorA<Iterator> a; |
---|
797 | // AdaptorB<Iterator> b; |
---|
798 | // |
---|
799 | // // This will result in a no such overload error in full operation |
---|
800 | // // If enable_if is not supported the static assert used |
---|
801 | // // in the operator implementation will fail. |
---|
802 | // // This will accidently work if is_convertible is not supported. |
---|
803 | // |
---|
804 | // a == b; |
---|
805 | // ---------------- |
---|
806 | // |
---|
807 | |
---|
808 | # ifdef BOOST_NO_ONE_WAY_ITERATOR_INTEROP |
---|
809 | # define BOOST_ITERATOR_CONVERTIBLE(a,b) mpl::true_() |
---|
810 | # else |
---|
811 | # define BOOST_ITERATOR_CONVERTIBLE(a,b) is_convertible<a,b>() |
---|
812 | # endif |
---|
813 | |
---|
814 | # define BOOST_ITERATOR_FACADE_INTEROP(op, result_type, return_prefix, base_op) \ |
---|
815 | BOOST_ITERATOR_FACADE_INTEROP_HEAD(inline, op, result_type) \ |
---|
816 | { \ |
---|
817 | /* For those compilers that do not support enable_if */ \ |
---|
818 | BOOST_STATIC_ASSERT(( \ |
---|
819 | is_interoperable< Derived1, Derived2 >::value \ |
---|
820 | )); \ |
---|
821 | return_prefix iterator_core_access::base_op( \ |
---|
822 | *static_cast<Derived1 const*>(&lhs) \ |
---|
823 | , *static_cast<Derived2 const*>(&rhs) \ |
---|
824 | , BOOST_ITERATOR_CONVERTIBLE(Derived2,Derived1) \ |
---|
825 | ); \ |
---|
826 | } |
---|
827 | |
---|
828 | # define BOOST_ITERATOR_FACADE_RELATION(op, return_prefix, base_op) \ |
---|
829 | BOOST_ITERATOR_FACADE_INTEROP( \ |
---|
830 | op \ |
---|
831 | , boost::detail::always_bool2 \ |
---|
832 | , return_prefix \ |
---|
833 | , base_op \ |
---|
834 | ) |
---|
835 | |
---|
836 | BOOST_ITERATOR_FACADE_RELATION(==, return, equal) |
---|
837 | BOOST_ITERATOR_FACADE_RELATION(!=, return !, equal) |
---|
838 | |
---|
839 | BOOST_ITERATOR_FACADE_RELATION(<, return 0 >, distance_from) |
---|
840 | BOOST_ITERATOR_FACADE_RELATION(>, return 0 <, distance_from) |
---|
841 | BOOST_ITERATOR_FACADE_RELATION(<=, return 0 >=, distance_from) |
---|
842 | BOOST_ITERATOR_FACADE_RELATION(>=, return 0 <=, distance_from) |
---|
843 | # undef BOOST_ITERATOR_FACADE_RELATION |
---|
844 | |
---|
845 | // operator- requires an additional part in the static assertion |
---|
846 | BOOST_ITERATOR_FACADE_INTEROP( |
---|
847 | - |
---|
848 | , boost::detail::choose_difference_type |
---|
849 | , return |
---|
850 | , distance_from |
---|
851 | ) |
---|
852 | # undef BOOST_ITERATOR_FACADE_INTEROP |
---|
853 | # undef BOOST_ITERATOR_FACADE_INTEROP_HEAD |
---|
854 | |
---|
855 | # define BOOST_ITERATOR_FACADE_PLUS(args) \ |
---|
856 | BOOST_ITERATOR_FACADE_PLUS_HEAD(inline, args) \ |
---|
857 | { \ |
---|
858 | Derived tmp(static_cast<Derived const&>(i)); \ |
---|
859 | return tmp += n; \ |
---|
860 | } |
---|
861 | |
---|
862 | BOOST_ITERATOR_FACADE_PLUS(( |
---|
863 | iterator_facade<Derived, V, TC, R, D> const& i |
---|
864 | , typename Derived::difference_type n |
---|
865 | )) |
---|
866 | |
---|
867 | BOOST_ITERATOR_FACADE_PLUS(( |
---|
868 | typename Derived::difference_type n |
---|
869 | , iterator_facade<Derived, V, TC, R, D> const& i |
---|
870 | )) |
---|
871 | # undef BOOST_ITERATOR_FACADE_PLUS |
---|
872 | # undef BOOST_ITERATOR_FACADE_PLUS_HEAD |
---|
873 | |
---|
874 | } // namespace boost |
---|
875 | |
---|
876 | #include <boost/iterator/detail/config_undef.hpp> |
---|
877 | |
---|
878 | #endif // BOOST_ITERATOR_FACADE_23022003THW_HPP |
---|