xref: /freebsd/contrib/llvm-project/libcxx/include/__iterator/move_iterator.h (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)
1 // -*- C++ -*-
2 //===----------------------------------------------------------------------===//
3 //
4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 // See https://llvm.org/LICENSE.txt for license information.
6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef _LIBCPP___ITERATOR_MOVE_ITERATOR_H
11 #define _LIBCPP___ITERATOR_MOVE_ITERATOR_H
12 
13 #include <__compare/compare_three_way_result.h>
14 #include <__compare/three_way_comparable.h>
15 #include <__concepts/assignable.h>
16 #include <__concepts/convertible_to.h>
17 #include <__concepts/derived_from.h>
18 #include <__concepts/same_as.h>
19 #include <__config>
20 #include <__iterator/concepts.h>
21 #include <__iterator/incrementable_traits.h>
22 #include <__iterator/iter_move.h>
23 #include <__iterator/iter_swap.h>
24 #include <__iterator/iterator_traits.h>
25 #include <__iterator/move_sentinel.h>
26 #include <__iterator/readable_traits.h>
27 #include <__type_traits/conditional.h>
28 #include <__type_traits/enable_if.h>
29 #include <__type_traits/is_assignable.h>
30 #include <__type_traits/is_constructible.h>
31 #include <__type_traits/is_convertible.h>
32 #include <__type_traits/is_reference.h>
33 #include <__type_traits/is_same.h>
34 #include <__type_traits/remove_reference.h>
35 #include <__utility/declval.h>
36 #include <__utility/move.h>
37 
38 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
39 #  pragma GCC system_header
40 #endif
41 
42 _LIBCPP_PUSH_MACROS
43 #include <__undef_macros>
44 
45 _LIBCPP_BEGIN_NAMESPACE_STD
46 
47 #if _LIBCPP_STD_VER >= 20
48 template <class _Iter, class = void>
49 struct __move_iter_category_base {};
50 
51 template <class _Iter>
52   requires requires { typename iterator_traits<_Iter>::iterator_category; }
53 struct __move_iter_category_base<_Iter> {
54   using iterator_category =
55       _If< derived_from<typename iterator_traits<_Iter>::iterator_category, random_access_iterator_tag>,
56            random_access_iterator_tag,
57            typename iterator_traits<_Iter>::iterator_category >;
58 };
59 
60 template <class _Iter, class _Sent>
61 concept __move_iter_comparable = requires {
62   { std::declval<const _Iter&>() == std::declval<_Sent>() } -> convertible_to<bool>;
63 };
64 #endif // _LIBCPP_STD_VER >= 20
65 
66 template <class _Iter>
67 class _LIBCPP_TEMPLATE_VIS move_iterator
68 #if _LIBCPP_STD_VER >= 20
69     : public __move_iter_category_base<_Iter>
70 #endif
71 {
72 #if _LIBCPP_STD_VER >= 20
73 
74 private:
75   _LIBCPP_HIDE_FROM_ABI static constexpr auto __get_iter_concept() {
76     if constexpr (random_access_iterator<_Iter>) {
77       return random_access_iterator_tag{};
78     } else if constexpr (bidirectional_iterator<_Iter>) {
79       return bidirectional_iterator_tag{};
80     } else if constexpr (forward_iterator<_Iter>) {
81       return forward_iterator_tag{};
82     } else {
83       return input_iterator_tag{};
84     }
85   }
86 #endif // _LIBCPP_STD_VER >= 20
87 
88 public:
89 #if _LIBCPP_STD_VER >= 20
90   using iterator_type    = _Iter;
91   using iterator_concept = decltype(__get_iter_concept());
92   // iterator_category is inherited and not always present
93   using value_type      = iter_value_t<_Iter>;
94   using difference_type = iter_difference_t<_Iter>;
95   using pointer         = _Iter;
96   using reference       = iter_rvalue_reference_t<_Iter>;
97 #else
98   typedef _Iter iterator_type;
99   typedef _If< __has_random_access_iterator_category<_Iter>::value,
100                random_access_iterator_tag,
101                typename iterator_traits<_Iter>::iterator_category >
102       iterator_category;
103   typedef typename iterator_traits<iterator_type>::value_type value_type;
104   typedef typename iterator_traits<iterator_type>::difference_type difference_type;
105   typedef iterator_type pointer;
106 
107   typedef typename iterator_traits<iterator_type>::reference __reference;
108   typedef __conditional_t<is_reference<__reference>::value, __libcpp_remove_reference_t<__reference>&&, __reference>
109       reference;
110 #endif // _LIBCPP_STD_VER >= 20
111 
112   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 explicit move_iterator(_Iter __i) : __current_(std::move(__i)) {}
113 
114   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator& operator++() {
115     ++__current_;
116     return *this;
117   }
118 
119   _LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 pointer operator->() const {
120     return __current_;
121   }
122 
123 #if _LIBCPP_STD_VER >= 20
124   _LIBCPP_HIDE_FROM_ABI constexpr move_iterator()
125     requires is_constructible_v<_Iter>
126       : __current_() {}
127 
128   template <class _Up>
129     requires(!_IsSame<_Up, _Iter>::value) && convertible_to<const _Up&, _Iter>
130   _LIBCPP_HIDE_FROM_ABI constexpr move_iterator(const move_iterator<_Up>& __u) : __current_(__u.base()) {}
131 
132   template <class _Up>
133     requires(!_IsSame<_Up, _Iter>::value) && convertible_to<const _Up&, _Iter> && assignable_from<_Iter&, const _Up&>
134   _LIBCPP_HIDE_FROM_ABI constexpr move_iterator& operator=(const move_iterator<_Up>& __u) {
135     __current_ = __u.base();
136     return *this;
137   }
138 
139   _LIBCPP_HIDE_FROM_ABI constexpr const _Iter& base() const& noexcept { return __current_; }
140   _LIBCPP_HIDE_FROM_ABI constexpr _Iter base() && { return std::move(__current_); }
141 
142   _LIBCPP_HIDE_FROM_ABI constexpr reference operator*() const { return ranges::iter_move(__current_); }
143   _LIBCPP_HIDE_FROM_ABI constexpr reference operator[](difference_type __n) const {
144     return ranges::iter_move(__current_ + __n);
145   }
146 
147   _LIBCPP_HIDE_FROM_ABI constexpr auto operator++(int)
148     requires forward_iterator<_Iter>
149   {
150     move_iterator __tmp(*this);
151     ++__current_;
152     return __tmp;
153   }
154 
155   _LIBCPP_HIDE_FROM_ABI constexpr void operator++(int) { ++__current_; }
156 #else
157   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator() : __current_() {}
158 
159   template <class _Up, __enable_if_t< !is_same<_Up, _Iter>::value && is_convertible<const _Up&, _Iter>::value, int> = 0>
160   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator(const move_iterator<_Up>& __u)
161       : __current_(__u.base()) {}
162 
163   template <class _Up,
164             __enable_if_t< !is_same<_Up, _Iter>::value && is_convertible<const _Up&, _Iter>::value &&
165                                is_assignable<_Iter&, const _Up&>::value,
166                            int> = 0>
167   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator& operator=(const move_iterator<_Up>& __u) {
168     __current_ = __u.base();
169     return *this;
170   }
171 
172   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 _Iter base() const { return __current_; }
173 
174   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reference operator*() const {
175     return static_cast<reference>(*__current_);
176   }
177   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reference operator[](difference_type __n) const {
178     return static_cast<reference>(__current_[__n]);
179   }
180 
181   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator operator++(int) {
182     move_iterator __tmp(*this);
183     ++__current_;
184     return __tmp;
185   }
186 #endif // _LIBCPP_STD_VER >= 20
187 
188   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator& operator--() {
189     --__current_;
190     return *this;
191   }
192   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator operator--(int) {
193     move_iterator __tmp(*this);
194     --__current_;
195     return __tmp;
196   }
197   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator operator+(difference_type __n) const {
198     return move_iterator(__current_ + __n);
199   }
200   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator& operator+=(difference_type __n) {
201     __current_ += __n;
202     return *this;
203   }
204   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator operator-(difference_type __n) const {
205     return move_iterator(__current_ - __n);
206   }
207   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator& operator-=(difference_type __n) {
208     __current_ -= __n;
209     return *this;
210   }
211 
212 #if _LIBCPP_STD_VER >= 20
213   template <sentinel_for<_Iter> _Sent>
214   friend _LIBCPP_HIDE_FROM_ABI constexpr bool operator==(const move_iterator& __x, const move_sentinel<_Sent>& __y)
215     requires __move_iter_comparable<_Iter, _Sent>
216   {
217     return __x.base() == __y.base();
218   }
219 
220   template <sized_sentinel_for<_Iter> _Sent>
221   friend _LIBCPP_HIDE_FROM_ABI constexpr iter_difference_t<_Iter>
222   operator-(const move_sentinel<_Sent>& __x, const move_iterator& __y) {
223     return __x.base() - __y.base();
224   }
225 
226   template <sized_sentinel_for<_Iter> _Sent>
227   friend _LIBCPP_HIDE_FROM_ABI constexpr iter_difference_t<_Iter>
228   operator-(const move_iterator& __x, const move_sentinel<_Sent>& __y) {
229     return __x.base() - __y.base();
230   }
231 
232   friend _LIBCPP_HIDE_FROM_ABI constexpr iter_rvalue_reference_t<_Iter>
233   iter_move(const move_iterator& __i) noexcept(noexcept(ranges::iter_move(__i.__current_))) {
234     return ranges::iter_move(__i.__current_);
235   }
236 
237   template <indirectly_swappable<_Iter> _It2>
238   friend _LIBCPP_HIDE_FROM_ABI constexpr void
239   iter_swap(const move_iterator& __x,
240             const move_iterator<_It2>& __y) noexcept(noexcept(ranges::iter_swap(__x.__current_, __y.__current_))) {
241     return ranges::iter_swap(__x.__current_, __y.__current_);
242   }
243 #endif // _LIBCPP_STD_VER >= 20
244 
245 private:
246   template <class _It2>
247   friend class move_iterator;
248 
249   _Iter __current_;
250 };
251 _LIBCPP_CTAD_SUPPORTED_FOR_TYPE(move_iterator);
252 
253 template <class _Iter1, class _Iter2>
254 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 bool
255 operator==(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y) {
256   return __x.base() == __y.base();
257 }
258 
259 #if _LIBCPP_STD_VER <= 17
260 template <class _Iter1, class _Iter2>
261 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 bool
262 operator!=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y) {
263   return __x.base() != __y.base();
264 }
265 #endif // _LIBCPP_STD_VER <= 17
266 
267 template <class _Iter1, class _Iter2>
268 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 bool
269 operator<(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y) {
270   return __x.base() < __y.base();
271 }
272 
273 template <class _Iter1, class _Iter2>
274 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 bool
275 operator>(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y) {
276   return __x.base() > __y.base();
277 }
278 
279 template <class _Iter1, class _Iter2>
280 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 bool
281 operator<=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y) {
282   return __x.base() <= __y.base();
283 }
284 
285 template <class _Iter1, class _Iter2>
286 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 bool
287 operator>=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y) {
288   return __x.base() >= __y.base();
289 }
290 
291 #if _LIBCPP_STD_VER >= 20
292 template <class _Iter1, three_way_comparable_with<_Iter1> _Iter2>
293 inline _LIBCPP_HIDE_FROM_ABI constexpr auto
294 operator<=>(const move_iterator<_Iter1>& __x,
295             const move_iterator<_Iter2>& __y) -> compare_three_way_result_t<_Iter1, _Iter2> {
296   return __x.base() <=> __y.base();
297 }
298 #endif // _LIBCPP_STD_VER >= 20
299 
300 #ifndef _LIBCPP_CXX03_LANG
301 template <class _Iter1, class _Iter2>
302 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 auto
303 operator-(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y) -> decltype(__x.base() - __y.base()) {
304   return __x.base() - __y.base();
305 }
306 #else
307 template <class _Iter1, class _Iter2>
308 inline _LIBCPP_HIDE_FROM_ABI typename move_iterator<_Iter1>::difference_type
309 operator-(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y) {
310   return __x.base() - __y.base();
311 }
312 #endif // !_LIBCPP_CXX03_LANG
313 
314 #if _LIBCPP_STD_VER >= 20
315 template <class _Iter>
316 inline _LIBCPP_HIDE_FROM_ABI constexpr move_iterator<_Iter>
317 operator+(iter_difference_t<_Iter> __n, const move_iterator<_Iter>& __x)
318   requires requires {
319     { __x.base() + __n } -> same_as<_Iter>;
320   }
321 {
322   return __x + __n;
323 }
324 #else
325 template <class _Iter>
326 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator<_Iter>
327 operator+(typename move_iterator<_Iter>::difference_type __n, const move_iterator<_Iter>& __x) {
328   return move_iterator<_Iter>(__x.base() + __n);
329 }
330 #endif // _LIBCPP_STD_VER >= 20
331 
332 #if _LIBCPP_STD_VER >= 20
333 template <class _Iter1, class _Iter2>
334   requires(!sized_sentinel_for<_Iter1, _Iter2>)
335 inline constexpr bool disable_sized_sentinel_for<move_iterator<_Iter1>, move_iterator<_Iter2>> = true;
336 #endif // _LIBCPP_STD_VER >= 20
337 
338 template <class _Iter>
339 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator<_Iter> make_move_iterator(_Iter __i) {
340   return move_iterator<_Iter>(std::move(__i));
341 }
342 
343 _LIBCPP_END_NAMESPACE_STD
344 
345 _LIBCPP_POP_MACROS
346 
347 #endif // _LIBCPP___ITERATOR_MOVE_ITERATOR_H
348