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42526146 PE |
1 | // Functions used by iterators -*- C++ -*- |
2 | ||
85ec4feb | 3 | // Copyright (C) 2001-2018 Free Software Foundation, Inc. |
42526146 PE |
4 | // |
5 | // This file is part of the GNU ISO C++ Library. This library is free | |
6 | // software; you can redistribute it and/or modify it under the | |
7 | // terms of the GNU General Public License as published by the | |
748086b7 | 8 | // Free Software Foundation; either version 3, or (at your option) |
42526146 PE |
9 | // any later version. |
10 | ||
11 | // This library is distributed in the hope that it will be useful, | |
12 | // but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | // GNU General Public License for more details. | |
15 | ||
748086b7 JJ |
16 | // Under Section 7 of GPL version 3, you are granted additional |
17 | // permissions described in the GCC Runtime Library Exception, version | |
18 | // 3.1, as published by the Free Software Foundation. | |
42526146 | 19 | |
748086b7 JJ |
20 | // You should have received a copy of the GNU General Public License and |
21 | // a copy of the GCC Runtime Library Exception along with this program; | |
22 | // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
23 | // <http://www.gnu.org/licenses/>. | |
42526146 | 24 | |
30a20a1e PE |
25 | /* |
26 | * | |
27 | * Copyright (c) 1994 | |
28 | * Hewlett-Packard Company | |
29 | * | |
30 | * Permission to use, copy, modify, distribute and sell this software | |
31 | * and its documentation for any purpose is hereby granted without fee, | |
32 | * provided that the above copyright notice appear in all copies and | |
33 | * that both that copyright notice and this permission notice appear | |
34 | * in supporting documentation. Hewlett-Packard Company makes no | |
35 | * representations about the suitability of this software for any | |
36 | * purpose. It is provided "as is" without express or implied warranty. | |
37 | * | |
38 | * | |
39 | * Copyright (c) 1996-1998 | |
40 | * Silicon Graphics Computer Systems, Inc. | |
41 | * | |
42 | * Permission to use, copy, modify, distribute and sell this software | |
43 | * and its documentation for any purpose is hereby granted without fee, | |
44 | * provided that the above copyright notice appear in all copies and | |
45 | * that both that copyright notice and this permission notice appear | |
46 | * in supporting documentation. Silicon Graphics makes no | |
47 | * representations about the suitability of this software for any | |
48 | * purpose. It is provided "as is" without express or implied warranty. | |
49 | */ | |
50 | ||
f910786b | 51 | /** @file bits/stl_iterator_base_funcs.h |
729e3d3f | 52 | * This is an internal header file, included by other library headers. |
f910786b | 53 | * Do not attempt to use it directly. @headername{iterator} |
8f94053d PE |
54 | * |
55 | * This file contains all of the general iterator-related utility | |
56 | * functions, such as distance() and advance(). | |
30a20a1e PE |
57 | */ |
58 | ||
046d30f4 PC |
59 | #ifndef _STL_ITERATOR_BASE_FUNCS_H |
60 | #define _STL_ITERATOR_BASE_FUNCS_H 1 | |
30a20a1e | 61 | |
30a20a1e | 62 | #pragma GCC system_header |
7ec62b25 | 63 | |
30a20a1e | 64 | #include <bits/concept_check.h> |
adad2a7d | 65 | #include <debug/assertions.h> |
30a20a1e | 66 | |
12ffa228 BK |
67 | namespace std _GLIBCXX_VISIBILITY(default) |
68 | { | |
4a15d842 FD |
69 | _GLIBCXX_BEGIN_NAMESPACE_VERSION |
70 | ||
194571f1 MG |
71 | _GLIBCXX_BEGIN_NAMESPACE_CONTAINER |
72 | // Forward declaration for the overloads of __distance. | |
73 | template <typename> struct _List_iterator; | |
74 | template <typename> struct _List_const_iterator; | |
75 | _GLIBCXX_END_NAMESPACE_CONTAINER | |
76 | ||
3971a4d2 | 77 | template<typename _InputIterator> |
06db9920 JW |
78 | inline _GLIBCXX14_CONSTEXPR |
79 | typename iterator_traits<_InputIterator>::difference_type | |
3971a4d2 PE |
80 | __distance(_InputIterator __first, _InputIterator __last, |
81 | input_iterator_tag) | |
82 | { | |
83 | // concept requirements | |
3d7c150e | 84 | __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) |
ed6814f7 | 85 | |
3971a4d2 | 86 | typename iterator_traits<_InputIterator>::difference_type __n = 0; |
f6592a9e PC |
87 | while (__first != __last) |
88 | { | |
89 | ++__first; | |
90 | ++__n; | |
91 | } | |
3971a4d2 | 92 | return __n; |
02d92e3b | 93 | } |
ed6814f7 | 94 | |
3971a4d2 | 95 | template<typename _RandomAccessIterator> |
06db9920 JW |
96 | inline _GLIBCXX14_CONSTEXPR |
97 | typename iterator_traits<_RandomAccessIterator>::difference_type | |
3971a4d2 PE |
98 | __distance(_RandomAccessIterator __first, _RandomAccessIterator __last, |
99 | random_access_iterator_tag) | |
100 | { | |
101 | // concept requirements | |
f6592a9e PC |
102 | __glibcxx_function_requires(_RandomAccessIteratorConcept< |
103 | _RandomAccessIterator>) | |
3971a4d2 PE |
104 | return __last - __first; |
105 | } | |
ed6814f7 | 106 | |
194571f1 MG |
107 | #if _GLIBCXX_USE_CXX11_ABI |
108 | // Forward declaration because of the qualified call in distance. | |
109 | template<typename _Tp> | |
110 | ptrdiff_t | |
111 | __distance(_GLIBCXX_STD_C::_List_iterator<_Tp>, | |
112 | _GLIBCXX_STD_C::_List_iterator<_Tp>, | |
113 | input_iterator_tag); | |
114 | ||
115 | template<typename _Tp> | |
116 | ptrdiff_t | |
117 | __distance(_GLIBCXX_STD_C::_List_const_iterator<_Tp>, | |
118 | _GLIBCXX_STD_C::_List_const_iterator<_Tp>, | |
119 | input_iterator_tag); | |
120 | #endif | |
121 | ||
3971a4d2 PE |
122 | /** |
123 | * @brief A generalization of pointer arithmetic. | |
93c66bc6 BK |
124 | * @param __first An input iterator. |
125 | * @param __last An input iterator. | |
3971a4d2 PE |
126 | * @return The distance between them. |
127 | * | |
93c66bc6 BK |
128 | * Returns @c n such that __first + n == __last. This requires |
129 | * that @p __last must be reachable from @p __first. Note that @c | |
130 | * n may be negative. | |
3971a4d2 PE |
131 | * |
132 | * For random access iterators, this uses their @c + and @c - operations | |
133 | * and are constant time. For other %iterator classes they are linear time. | |
134 | */ | |
135 | template<typename _InputIterator> | |
06db9920 JW |
136 | inline _GLIBCXX17_CONSTEXPR |
137 | typename iterator_traits<_InputIterator>::difference_type | |
3971a4d2 PE |
138 | distance(_InputIterator __first, _InputIterator __last) |
139 | { | |
140 | // concept requirements -- taken care of in __distance | |
f6592a9e PC |
141 | return std::__distance(__first, __last, |
142 | std::__iterator_category(__first)); | |
3971a4d2 | 143 | } |
ed6814f7 | 144 | |
08addde6 | 145 | template<typename _InputIterator, typename _Distance> |
06db9920 | 146 | inline _GLIBCXX14_CONSTEXPR void |
08addde6 | 147 | __advance(_InputIterator& __i, _Distance __n, input_iterator_tag) |
3971a4d2 PE |
148 | { |
149 | // concept requirements | |
3d7c150e | 150 | __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) |
2f1e8e7c | 151 | __glibcxx_assert(__n >= 0); |
f6592a9e PC |
152 | while (__n--) |
153 | ++__i; | |
3971a4d2 | 154 | } |
ed6814f7 | 155 | |
3971a4d2 | 156 | template<typename _BidirectionalIterator, typename _Distance> |
06db9920 | 157 | inline _GLIBCXX14_CONSTEXPR void |
3971a4d2 | 158 | __advance(_BidirectionalIterator& __i, _Distance __n, |
8f407473 | 159 | bidirectional_iterator_tag) |
3971a4d2 PE |
160 | { |
161 | // concept requirements | |
f6592a9e PC |
162 | __glibcxx_function_requires(_BidirectionalIteratorConcept< |
163 | _BidirectionalIterator>) | |
3971a4d2 | 164 | if (__n > 0) |
83042fca PC |
165 | while (__n--) |
166 | ++__i; | |
3971a4d2 | 167 | else |
83042fca PC |
168 | while (__n++) |
169 | --__i; | |
3971a4d2 | 170 | } |
ed6814f7 | 171 | |
3971a4d2 | 172 | template<typename _RandomAccessIterator, typename _Distance> |
06db9920 | 173 | inline _GLIBCXX14_CONSTEXPR void |
3971a4d2 PE |
174 | __advance(_RandomAccessIterator& __i, _Distance __n, |
175 | random_access_iterator_tag) | |
176 | { | |
177 | // concept requirements | |
f6592a9e PC |
178 | __glibcxx_function_requires(_RandomAccessIteratorConcept< |
179 | _RandomAccessIterator>) | |
6c241778 JW |
180 | if (__builtin_constant_p(__n) && __n == 1) |
181 | ++__i; | |
182 | else if (__builtin_constant_p(__n) && __n == -1) | |
183 | --__i; | |
184 | else | |
185 | __i += __n; | |
3971a4d2 | 186 | } |
ed6814f7 | 187 | |
3971a4d2 PE |
188 | /** |
189 | * @brief A generalization of pointer arithmetic. | |
93c66bc6 BK |
190 | * @param __i An input iterator. |
191 | * @param __n The @a delta by which to change @p __i. | |
3971a4d2 PE |
192 | * @return Nothing. |
193 | * | |
194 | * This increments @p i by @p n. For bidirectional and random access | |
93c66bc6 | 195 | * iterators, @p __n may be negative, in which case @p __i is decremented. |
3971a4d2 PE |
196 | * |
197 | * For random access iterators, this uses their @c + and @c - operations | |
198 | * and are constant time. For other %iterator classes they are linear time. | |
199 | */ | |
200 | template<typename _InputIterator, typename _Distance> | |
06db9920 | 201 | inline _GLIBCXX17_CONSTEXPR void |
3971a4d2 PE |
202 | advance(_InputIterator& __i, _Distance __n) |
203 | { | |
204 | // concept requirements -- taken care of in __advance | |
8f407473 PC |
205 | typename iterator_traits<_InputIterator>::difference_type __d = __n; |
206 | std::__advance(__i, __d, std::__iterator_category(__i)); | |
3971a4d2 | 207 | } |
3cbc7af0 | 208 | |
734f5023 | 209 | #if __cplusplus >= 201103L |
7ec62b25 | 210 | |
7b7b60c8 VV |
211 | template<typename _InputIterator> |
212 | inline _GLIBCXX17_CONSTEXPR _InputIterator | |
213 | next(_InputIterator __x, typename | |
214 | iterator_traits<_InputIterator>::difference_type __n = 1) | |
65b0413a | 215 | { |
500dc9a6 | 216 | // concept requirements |
7b7b60c8 | 217 | __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) |
65b0413a CF |
218 | std::advance(__x, __n); |
219 | return __x; | |
220 | } | |
221 | ||
222 | template<typename _BidirectionalIterator> | |
06db9920 | 223 | inline _GLIBCXX17_CONSTEXPR _BidirectionalIterator |
1a9e603e PC |
224 | prev(_BidirectionalIterator __x, typename |
225 | iterator_traits<_BidirectionalIterator>::difference_type __n = 1) | |
65b0413a | 226 | { |
500dc9a6 JW |
227 | // concept requirements |
228 | __glibcxx_function_requires(_BidirectionalIteratorConcept< | |
229 | _BidirectionalIterator>) | |
65b0413a CF |
230 | std::advance(__x, -__n); |
231 | return __x; | |
232 | } | |
65b0413a | 233 | |
734f5023 | 234 | #endif // C++11 |
7ec62b25 | 235 | |
12ffa228 BK |
236 | _GLIBCXX_END_NAMESPACE_VERSION |
237 | } // namespace | |
ccef29e8 | 238 | |
046d30f4 | 239 | #endif /* _STL_ITERATOR_BASE_FUNCS_H */ |