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1 | // Boost.Range library |
2 | // | |
3 | // Copyright Neil Groves 2009. | |
4 | // Use, modification and distribution is subject to the Boost Software | |
5 | // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at | |
6 | // http://www.boost.org/LICENSE_1_0.txt) | |
7 | // | |
8 | // For more information, see http://www.boost.org/libs/range/ | |
9 | // | |
10 | #ifndef BOOST_RANGE_ALGORITHM_EQUAL_HPP_INCLUDED | |
11 | #define BOOST_RANGE_ALGORITHM_EQUAL_HPP_INCLUDED | |
12 | ||
13 | #include <boost/config.hpp> | |
14 | #include <boost/range/concepts.hpp> | |
15 | #include <iterator> | |
16 | ||
17 | namespace boost | |
18 | { | |
19 | namespace range_detail | |
20 | { | |
21 | // An implementation of equality comparison that is optimized for iterator | |
22 | // traversal categories less than RandomAccessTraversal. | |
23 | template< class SinglePassTraversalReadableIterator1, | |
24 | class SinglePassTraversalReadableIterator2, | |
25 | class IteratorCategoryTag1, | |
26 | class IteratorCategoryTag2 > | |
27 | inline bool equal_impl( SinglePassTraversalReadableIterator1 first1, | |
28 | SinglePassTraversalReadableIterator1 last1, | |
29 | SinglePassTraversalReadableIterator2 first2, | |
30 | SinglePassTraversalReadableIterator2 last2, | |
31 | IteratorCategoryTag1, | |
32 | IteratorCategoryTag2 ) | |
33 | { | |
34 | for (;;) | |
35 | { | |
36 | // If we have reached the end of the left range then this is | |
37 | // the end of the loop. They are equal if and only if we have | |
38 | // simultaneously reached the end of the right range. | |
39 | if (first1 == last1) | |
40 | return first2 == last2; | |
41 | ||
42 | // If we have reached the end of the right range at this line | |
43 | // it indicates that the right range is shorter than the left | |
44 | // and hence the result is false. | |
45 | if (first2 == last2) | |
46 | return false; | |
47 | ||
48 | // continue looping if and only if the values are equal | |
49 | if (*first1 != *first2) | |
50 | break; | |
51 | ||
52 | ++first1; | |
53 | ++first2; | |
54 | } | |
55 | ||
56 | // Reaching this line in the algorithm indicates that a value | |
57 | // inequality has been detected. | |
58 | return false; | |
59 | } | |
60 | ||
61 | template< class SinglePassTraversalReadableIterator1, | |
62 | class SinglePassTraversalReadableIterator2, | |
63 | class IteratorCategoryTag1, | |
64 | class IteratorCategoryTag2, | |
65 | class BinaryPredicate > | |
66 | inline bool equal_impl( SinglePassTraversalReadableIterator1 first1, | |
67 | SinglePassTraversalReadableIterator1 last1, | |
68 | SinglePassTraversalReadableIterator2 first2, | |
69 | SinglePassTraversalReadableIterator2 last2, | |
70 | BinaryPredicate pred, | |
71 | IteratorCategoryTag1, | |
72 | IteratorCategoryTag2 ) | |
73 | { | |
74 | for (;;) | |
75 | { | |
76 | // If we have reached the end of the left range then this is | |
77 | // the end of the loop. They are equal if and only if we have | |
78 | // simultaneously reached the end of the right range. | |
79 | if (first1 == last1) | |
80 | return first2 == last2; | |
81 | ||
82 | // If we have reached the end of the right range at this line | |
83 | // it indicates that the right range is shorter than the left | |
84 | // and hence the result is false. | |
85 | if (first2 == last2) | |
86 | return false; | |
87 | ||
88 | // continue looping if and only if the values are equal | |
89 | if (!pred(*first1, *first2)) | |
90 | break; | |
91 | ||
92 | ++first1; | |
93 | ++first2; | |
94 | } | |
95 | ||
96 | // Reaching this line in the algorithm indicates that a value | |
97 | // inequality has been detected. | |
98 | return false; | |
99 | } | |
100 | ||
101 | // An implementation of equality comparison that is optimized for | |
102 | // random access iterators. | |
103 | template< class RandomAccessTraversalReadableIterator1, | |
104 | class RandomAccessTraversalReadableIterator2 > | |
105 | inline bool equal_impl( RandomAccessTraversalReadableIterator1 first1, | |
106 | RandomAccessTraversalReadableIterator1 last1, | |
107 | RandomAccessTraversalReadableIterator2 first2, | |
108 | RandomAccessTraversalReadableIterator2 last2, | |
109 | std::random_access_iterator_tag, | |
110 | std::random_access_iterator_tag ) | |
111 | { | |
112 | return ((last1 - first1) == (last2 - first2)) | |
113 | && std::equal(first1, last1, first2); | |
114 | } | |
115 | ||
116 | template< class RandomAccessTraversalReadableIterator1, | |
117 | class RandomAccessTraversalReadableIterator2, | |
118 | class BinaryPredicate > | |
119 | inline bool equal_impl( RandomAccessTraversalReadableIterator1 first1, | |
120 | RandomAccessTraversalReadableIterator1 last1, | |
121 | RandomAccessTraversalReadableIterator2 first2, | |
122 | RandomAccessTraversalReadableIterator2 last2, | |
123 | BinaryPredicate pred, | |
124 | std::random_access_iterator_tag, | |
125 | std::random_access_iterator_tag ) | |
126 | { | |
127 | return ((last1 - first1) == (last2 - first2)) | |
128 | && std::equal(first1, last1, first2, pred); | |
129 | } | |
130 | ||
131 | template< class SinglePassTraversalReadableIterator1, | |
132 | class SinglePassTraversalReadableIterator2 > | |
133 | inline bool equal( SinglePassTraversalReadableIterator1 first1, | |
134 | SinglePassTraversalReadableIterator1 last1, | |
135 | SinglePassTraversalReadableIterator2 first2, | |
136 | SinglePassTraversalReadableIterator2 last2 ) | |
137 | { | |
138 | BOOST_DEDUCED_TYPENAME std::iterator_traits< SinglePassTraversalReadableIterator1 >::iterator_category tag1; | |
139 | BOOST_DEDUCED_TYPENAME std::iterator_traits< SinglePassTraversalReadableIterator2 >::iterator_category tag2; | |
140 | ||
141 | return equal_impl(first1, last1, first2, last2, tag1, tag2); | |
142 | } | |
143 | ||
144 | template< class SinglePassTraversalReadableIterator1, | |
145 | class SinglePassTraversalReadableIterator2, | |
146 | class BinaryPredicate > | |
147 | inline bool equal( SinglePassTraversalReadableIterator1 first1, | |
148 | SinglePassTraversalReadableIterator1 last1, | |
149 | SinglePassTraversalReadableIterator2 first2, | |
150 | SinglePassTraversalReadableIterator2 last2, | |
151 | BinaryPredicate pred ) | |
152 | { | |
153 | BOOST_DEDUCED_TYPENAME std::iterator_traits< SinglePassTraversalReadableIterator1 >::iterator_category tag1; | |
154 | BOOST_DEDUCED_TYPENAME std::iterator_traits< SinglePassTraversalReadableIterator2 >::iterator_category tag2; | |
155 | ||
156 | return equal_impl(first1, last1, first2, last2, pred, tag1, tag2); | |
157 | } | |
158 | ||
159 | } // namespace range_detail | |
160 | ||
161 | namespace range | |
162 | { | |
163 | ||
164 | /// \brief template function equal | |
165 | /// | |
166 | /// range-based version of the equal std algorithm | |
167 | /// | |
168 | /// \pre SinglePassRange1 is a model of the SinglePassRangeConcept | |
169 | /// \pre SinglePassRange2 is a model of the SinglePassRangeConcept | |
170 | /// \pre BinaryPredicate is a model of the BinaryPredicateConcept | |
171 | template< class SinglePassRange1, class SinglePassRange2 > | |
172 | inline bool equal( const SinglePassRange1& rng1, const SinglePassRange2& rng2 ) | |
173 | { | |
174 | BOOST_RANGE_CONCEPT_ASSERT(( SinglePassRangeConcept<const SinglePassRange1> )); | |
175 | BOOST_RANGE_CONCEPT_ASSERT(( SinglePassRangeConcept<const SinglePassRange2> )); | |
176 | ||
177 | return ::boost::range_detail::equal( | |
178 | ::boost::begin(rng1), ::boost::end(rng1), | |
179 | ::boost::begin(rng2), ::boost::end(rng2) ); | |
180 | } | |
181 | ||
182 | /// \overload | |
183 | template< class SinglePassRange1, class SinglePassRange2, class BinaryPredicate > | |
184 | inline bool equal( const SinglePassRange1& rng1, const SinglePassRange2& rng2, | |
185 | BinaryPredicate pred ) | |
186 | { | |
187 | BOOST_RANGE_CONCEPT_ASSERT(( SinglePassRangeConcept<const SinglePassRange1> )); | |
188 | BOOST_RANGE_CONCEPT_ASSERT(( SinglePassRangeConcept<const SinglePassRange2> )); | |
189 | ||
190 | return ::boost::range_detail::equal( | |
191 | ::boost::begin(rng1), ::boost::end(rng1), | |
192 | ::boost::begin(rng2), ::boost::end(rng2), | |
193 | pred); | |
194 | } | |
195 | ||
196 | } // namespace range | |
197 | using ::boost::range::equal; | |
198 | } // namespace boost | |
199 | ||
200 | #endif // include guard |