1 | // Boost.Range library |
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2 | // |
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3 | // Copyright Neil Groves 2009. |
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4 | // Use, modification and distribution is subject to the Boost Software |
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5 | // License, Version 1.0. (See 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 | // |
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8 | // For more information, see http://www.boost.org/libs/range/ |
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9 | // |
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10 | #ifndef BOOST_RANGE_ALGORITHM_EQUAL_HPP_INCLUDED |
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11 | #define BOOST_RANGE_ALGORITHM_EQUAL_HPP_INCLUDED |
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12 | |
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13 | #include <boost/config.hpp> |
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14 | #include <boost/range/concepts.hpp> |
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15 | #include <iterator> |
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16 | |
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17 | namespace boost |
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18 | { |
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19 | namespace range_detail |
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20 | { |
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21 | // An implementation of equality comparison that is optimized for iterator |
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22 | // traversal categories less than RandomAccessTraversal. |
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23 | template< class SinglePassTraversalReadableIterator1, |
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24 | class SinglePassTraversalReadableIterator2, |
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25 | class IteratorCategoryTag1, |
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26 | class IteratorCategoryTag2 > |
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27 | inline bool equal_impl( SinglePassTraversalReadableIterator1 first1, |
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28 | SinglePassTraversalReadableIterator1 last1, |
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29 | SinglePassTraversalReadableIterator2 first2, |
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30 | SinglePassTraversalReadableIterator2 last2, |
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31 | IteratorCategoryTag1, |
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32 | IteratorCategoryTag2 ) |
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33 | { |
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34 | do |
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35 | { |
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36 | // If we have reached the end of the left range then this is |
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37 | // the end of the loop. They are equal if and only if we have |
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38 | // simultaneously reached the end of the right range. |
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39 | if (first1 == last1) |
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40 | return first2 == last2; |
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41 | |
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42 | // If we have reached the end of the right range at this line |
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43 | // it indicates that the right range is shorter than the left |
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44 | // and hence the result is false. |
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45 | if (first2 == last2) |
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46 | return false; |
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47 | |
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48 | // continue looping if and only if the values are equal |
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49 | } while(*first1++ == *first2++); |
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50 | |
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51 | // Reaching this line in the algorithm indicates that a value |
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52 | // inequality has been detected. |
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53 | return false; |
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54 | } |
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55 | |
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56 | template< class SinglePassTraversalReadableIterator1, |
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57 | class SinglePassTraversalReadableIterator2, |
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58 | class IteratorCategoryTag1, |
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59 | class IteratorCategoryTag2, |
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60 | class BinaryPredicate > |
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61 | inline bool equal_impl( SinglePassTraversalReadableIterator1 first1, |
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62 | SinglePassTraversalReadableIterator1 last1, |
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63 | SinglePassTraversalReadableIterator2 first2, |
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64 | SinglePassTraversalReadableIterator2 last2, |
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65 | BinaryPredicate pred, |
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66 | IteratorCategoryTag1, |
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67 | IteratorCategoryTag2 ) |
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68 | { |
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69 | do |
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70 | { |
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71 | // If we have reached the end of the left range then this is |
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72 | // the end of the loop. They are equal if and only if we have |
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73 | // simultaneously reached the end of the right range. |
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74 | if (first1 == last1) |
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75 | return first2 == last2; |
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76 | |
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77 | // If we have reached the end of the right range at this line |
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78 | // it indicates that the right range is shorter than the left |
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79 | // and hence the result is false. |
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80 | if (first2 == last2) |
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81 | return false; |
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82 | |
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83 | // continue looping if and only if the values are equal |
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84 | } while(pred(*first1++, *first2++)); |
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85 | |
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86 | // Reaching this line in the algorithm indicates that a value |
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87 | // inequality has been detected. |
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88 | return false; |
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89 | } |
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90 | |
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91 | // An implementation of equality comparison that is optimized for |
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92 | // random access iterators. |
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93 | template< class RandomAccessTraversalReadableIterator1, |
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94 | class RandomAccessTraversalReadableIterator2 > |
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95 | inline bool equal_impl( RandomAccessTraversalReadableIterator1 first1, |
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96 | RandomAccessTraversalReadableIterator1 last1, |
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97 | RandomAccessTraversalReadableIterator2 first2, |
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98 | RandomAccessTraversalReadableIterator2 last2, |
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99 | std::random_access_iterator_tag, |
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100 | std::random_access_iterator_tag ) |
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101 | { |
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102 | return ((last1 - first1) == (last2 - first2)) |
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103 | && std::equal(first1, last1, first2); |
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104 | } |
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105 | |
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106 | template< class RandomAccessTraversalReadableIterator1, |
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107 | class RandomAccessTraversalReadableIterator2, |
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108 | class BinaryPredicate > |
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109 | inline bool equal_impl( RandomAccessTraversalReadableIterator1 first1, |
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110 | RandomAccessTraversalReadableIterator1 last1, |
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111 | RandomAccessTraversalReadableIterator2 first2, |
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112 | RandomAccessTraversalReadableIterator2 last2, |
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113 | BinaryPredicate pred ) |
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114 | { |
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115 | return ((last1 - first1) == (last2 - first2)) |
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116 | && std::equal(first1, last1, first2, pred); |
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117 | } |
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118 | |
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119 | template< class SinglePassTraversalReadableIterator1, |
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120 | class SinglePassTraversalReadableIterator2 > |
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121 | inline bool equal( SinglePassTraversalReadableIterator1 first1, |
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122 | SinglePassTraversalReadableIterator1 last1, |
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123 | SinglePassTraversalReadableIterator2 first2, |
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124 | SinglePassTraversalReadableIterator2 last2 ) |
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125 | { |
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126 | BOOST_DEDUCED_TYPENAME std::iterator_traits< SinglePassTraversalReadableIterator1 >::iterator_category tag1; |
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127 | BOOST_DEDUCED_TYPENAME std::iterator_traits< SinglePassTraversalReadableIterator2 >::iterator_category tag2; |
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128 | |
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129 | return equal_impl(first1, last1, first2, last2, tag1, tag2); |
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130 | } |
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131 | |
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132 | template< class SinglePassTraversalReadableIterator1, |
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133 | class SinglePassTraversalReadableIterator2, |
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134 | class BinaryPredicate > |
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135 | inline bool equal( SinglePassTraversalReadableIterator1 first1, |
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136 | SinglePassTraversalReadableIterator1 last1, |
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137 | SinglePassTraversalReadableIterator2 first2, |
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138 | SinglePassTraversalReadableIterator2 last2, |
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139 | BinaryPredicate pred ) |
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140 | { |
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141 | BOOST_DEDUCED_TYPENAME std::iterator_traits< SinglePassTraversalReadableIterator1 >::iterator_category tag1; |
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142 | BOOST_DEDUCED_TYPENAME std::iterator_traits< SinglePassTraversalReadableIterator2 >::iterator_category tag2; |
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143 | |
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144 | return equal_impl(first1, last1, first2, last2, pred, tag1, tag2); |
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145 | } |
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146 | |
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147 | } // namespace range_detail |
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148 | |
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149 | namespace range |
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150 | { |
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151 | |
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152 | /// \brief template function equal |
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153 | /// |
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154 | /// range-based version of the equal std algorithm |
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155 | /// |
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156 | /// \pre SinglePassRange1 is a model of the SinglePassRangeConcept |
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157 | /// \pre SinglePassRange2 is a model of the SinglePassRangeConcept |
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158 | /// \pre BinaryPredicate is a model of the BinaryPredicateConcept |
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159 | template< class SinglePassRange1, class SinglePassRange2 > |
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160 | inline bool equal( const SinglePassRange1& rng1, const SinglePassRange2& rng2 ) |
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161 | { |
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162 | BOOST_RANGE_CONCEPT_ASSERT(( SinglePassRangeConcept<const SinglePassRange1> )); |
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163 | BOOST_RANGE_CONCEPT_ASSERT(( SinglePassRangeConcept<const SinglePassRange2> )); |
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164 | |
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165 | return ::boost::range_detail::equal( |
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166 | ::boost::begin(rng1), ::boost::end(rng1), |
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167 | ::boost::begin(rng2), ::boost::end(rng2) ); |
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168 | } |
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169 | |
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170 | /// \overload |
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171 | template< class SinglePassRange1, class SinglePassRange2, class BinaryPredicate > |
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172 | inline bool equal( const SinglePassRange1& rng1, const SinglePassRange2& rng2, |
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173 | BinaryPredicate pred ) |
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174 | { |
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175 | BOOST_RANGE_CONCEPT_ASSERT(( SinglePassRangeConcept<const SinglePassRange1> )); |
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176 | BOOST_RANGE_CONCEPT_ASSERT(( SinglePassRangeConcept<const SinglePassRange2> )); |
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177 | |
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178 | return ::boost::range_detail::equal( |
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179 | ::boost::begin(rng1), ::boost::end(rng1), |
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180 | ::boost::begin(rng2), ::boost::end(rng2), |
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181 | pred); |
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182 | } |
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183 | |
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184 | } // namespace range |
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185 | using range::equal; |
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186 | } // namespace boost |
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187 | |
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188 | #endif // include guard |
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