1 // Functions used by iterators -*- C++ -*-
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56 /* NOTE: This is an internal header file, included by other STL headers.
57 * You should not attempt to use it directly.
60 #ifndef __SGI_STL_INTERNAL_ITERATOR_BASE_FUNCS_H
61 #define __SGI_STL_INTERNAL_ITERATOR_BASE_FUNCS_H
63 // This file contains all of the general iterator-related utility
64 // functions, such as distance() and advance().
65 // The internal file stl_iterator.h contains predefined iterators,
66 // such as front_insert_iterator and istream_iterator.
68 #pragma GCC system_header
69 #include <bits/concept_check.h>
74 // There are two signatures for distance. In addition to the one taking
75 // two iterators and returning a result, there is another taking two
76 // iterators and a reference-to-result variable, and returning nothing.
77 // The latter seems to be an SGI extension. -- pedwards
78 template<typename _InputIterator, typename _Distance>
80 __distance(_InputIterator __first, _InputIterator __last,
81 _Distance& __n, input_iterator_tag)
83 // concept requirements
84 __glibcpp_function_requires(_InputIteratorConcept<_InputIterator>);
85 while (__first != __last) { ++__first; ++__n; }
88 template<typename _RandomAccessIterator, typename _Distance>
90 __distance(_RandomAccessIterator __first, _RandomAccessIterator __last,
91 _Distance& __n, random_access_iterator_tag)
93 // concept requirements
94 __glibcpp_function_requires(_RandomAccessIteratorConcept<_RandomAccessIterator>);
95 __n += __last - __first;
98 template<typename _InputIterator, typename _Distance>
100 distance(_InputIterator __first, _InputIterator __last,
103 // concept requirements -- taken care of in __distance
104 __distance(__first, __last, __n, __iterator_category(__first));
107 template<typename _InputIterator>
108 inline typename iterator_traits<_InputIterator>::difference_type
109 __distance(_InputIterator __first, _InputIterator __last, input_iterator_tag)
111 // concept requirements
112 __glibcpp_function_requires(_InputIteratorConcept<_InputIterator>);
113 typename iterator_traits<_InputIterator>::difference_type __n = 0;
114 while (__first != __last) {
120 template<typename _RandomAccessIterator>
121 inline typename iterator_traits<_RandomAccessIterator>::difference_type
122 __distance(_RandomAccessIterator __first, _RandomAccessIterator __last,
123 random_access_iterator_tag)
125 // concept requirements
126 __glibcpp_function_requires(_RandomAccessIteratorConcept<_RandomAccessIterator>);
127 return __last - __first;
130 template<typename _InputIterator>
131 inline typename iterator_traits<_InputIterator>::difference_type
132 distance(_InputIterator __first, _InputIterator __last)
134 // concept requirements -- taken care of in __distance
135 return __distance(__first, __last, __iterator_category(__first));
138 template<typename _InputIter, typename _Distance>
140 __advance(_InputIter& __i, _Distance __n, input_iterator_tag)
142 // concept requirements
143 __glibcpp_function_requires(_InputIteratorConcept<_InputIter>);
147 template<typename _BidirectionalIterator, typename _Distance>
149 __advance(_BidirectionalIterator& __i, _Distance __n, bidirectional_iterator_tag)
151 // concept requirements
152 __glibcpp_function_requires(_BidirectionalIteratorConcept<_BidirectionalIterator>);
159 template<typename _RandomAccessIterator, typename _Distance>
161 __advance(_RandomAccessIterator& __i, _Distance __n, random_access_iterator_tag)
163 // concept requirements
164 __glibcpp_function_requires(_RandomAccessIteratorConcept<_RandomAccessIterator>);
168 template<typename _InputIterator, typename _Distance>
170 advance(_InputIterator& __i, _Distance __n)
172 // concept requirements -- taken care of in __advance
173 __advance(__i, __n, __iterator_category(__i));
178 #endif /* __SGI_STL_INTERNAL_ITERATOR_BASE_FUNCS_H */