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 typename conditional< is_reference<__reference>::value,
109                                 __libcpp_remove_reference_t<__reference>&&,
110                                 __reference >::type reference;
111 #endif // _LIBCPP_STD_VER >= 20
112 
113   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 explicit move_iterator(_Iter __i) : __current_(std::move(__i)) {}
114 
115   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator& operator++() {
116     ++__current_;
117     return *this;
118   }
119 
120   _LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 pointer operator->() const {
121     return __current_;
122   }
123 
124 #if _LIBCPP_STD_VER >= 20
125   _LIBCPP_HIDE_FROM_ABI constexpr move_iterator()
126     requires is_constructible_v<_Iter>
127       : __current_() {}
128 
129   template <class _Up>
130     requires(!_IsSame<_Up, _Iter>::value) && convertible_to<const _Up&, _Iter>
131   _LIBCPP_HIDE_FROM_ABI constexpr move_iterator(const move_iterator<_Up>& __u) : __current_(__u.base()) {}
132 
133   template <class _Up>
134     requires(!_IsSame<_Up, _Iter>::value) && convertible_to<const _Up&, _Iter> && assignable_from<_Iter&, const _Up&>
135   _LIBCPP_HIDE_FROM_ABI constexpr move_iterator& operator=(const move_iterator<_Up>& __u) {
136     __current_ = __u.base();
137     return *this;
138   }
139 
140   _LIBCPP_HIDE_FROM_ABI constexpr const _Iter& base() const& noexcept { return __current_; }
141   _LIBCPP_HIDE_FROM_ABI constexpr _Iter base() && { return std::move(__current_); }
142 
143   _LIBCPP_HIDE_FROM_ABI constexpr reference operator*() const { return ranges::iter_move(__current_); }
144   _LIBCPP_HIDE_FROM_ABI constexpr reference operator[](difference_type __n) const {
145     return ranges::iter_move(__current_ + __n);
146   }
147 
148   _LIBCPP_HIDE_FROM_ABI constexpr auto operator++(int)
149     requires forward_iterator<_Iter>
150   {
151     move_iterator __tmp(*this);
152     ++__current_;
153     return __tmp;
154   }
155 
156   _LIBCPP_HIDE_FROM_ABI constexpr void operator++(int) { ++__current_; }
157 #else
158   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator() : __current_() {}
159 
160   template <class _Up,
161             class = __enable_if_t< !is_same<_Up, _Iter>::value && is_convertible<const _Up&, _Iter>::value > >
162   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator(const move_iterator<_Up>& __u)
163       : __current_(__u.base()) {}
164 
165   template <class _Up,
166             class = __enable_if_t< !is_same<_Up, _Iter>::value && is_convertible<const _Up&, _Iter>::value &&
167                                    is_assignable<_Iter&, const _Up&>::value > >
168   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator& operator=(const move_iterator<_Up>& __u) {
169     __current_ = __u.base();
170     return *this;
171   }
172 
173   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 _Iter base() const { return __current_; }
174 
175   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reference operator*() const {
176     return static_cast<reference>(*__current_);
177   }
178   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 reference operator[](difference_type __n) const {
179     return static_cast<reference>(__current_[__n]);
180   }
181 
182   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator operator++(int) {
183     move_iterator __tmp(*this);
184     ++__current_;
185     return __tmp;
186   }
187 #endif // _LIBCPP_STD_VER >= 20
188 
189   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator& operator--() {
190     --__current_;
191     return *this;
192   }
193   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator operator--(int) {
194     move_iterator __tmp(*this);
195     --__current_;
196     return __tmp;
197   }
198   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator operator+(difference_type __n) const {
199     return move_iterator(__current_ + __n);
200   }
201   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator& operator+=(difference_type __n) {
202     __current_ += __n;
203     return *this;
204   }
205   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator operator-(difference_type __n) const {
206     return move_iterator(__current_ - __n);
207   }
208   _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator& operator-=(difference_type __n) {
209     __current_ -= __n;
210     return *this;
211   }
212 
213 #if _LIBCPP_STD_VER >= 20
214   template <sentinel_for<_Iter> _Sent>
215   friend _LIBCPP_HIDE_FROM_ABI constexpr bool operator==(const move_iterator& __x, const move_sentinel<_Sent>& __y)
216     requires __move_iter_comparable<_Iter, _Sent>
217   {
218     return __x.base() == __y.base();
219   }
220 
221   template <sized_sentinel_for<_Iter> _Sent>
222   friend _LIBCPP_HIDE_FROM_ABI constexpr iter_difference_t<_Iter>
223   operator-(const move_sentinel<_Sent>& __x, const move_iterator& __y) {
224     return __x.base() - __y.base();
225   }
226 
227   template <sized_sentinel_for<_Iter> _Sent>
228   friend _LIBCPP_HIDE_FROM_ABI constexpr iter_difference_t<_Iter>
229   operator-(const move_iterator& __x, const move_sentinel<_Sent>& __y) {
230     return __x.base() - __y.base();
231   }
232 
233   friend _LIBCPP_HIDE_FROM_ABI constexpr iter_rvalue_reference_t<_Iter>
234   iter_move(const move_iterator& __i) noexcept(noexcept(ranges::iter_move(__i.__current_))) {
235     return ranges::iter_move(__i.__current_);
236   }
237 
238   template <indirectly_swappable<_Iter> _It2>
239   friend _LIBCPP_HIDE_FROM_ABI constexpr void
240   iter_swap(const move_iterator& __x,
241             const move_iterator<_It2>& __y) noexcept(noexcept(ranges::iter_swap(__x.__current_, __y.__current_))) {
242     return ranges::iter_swap(__x.__current_, __y.__current_);
243   }
244 #endif // _LIBCPP_STD_VER >= 20
245 
246 private:
247   template <class _It2>
248   friend class move_iterator;
249 
250   _Iter __current_;
251 };
252 _LIBCPP_CTAD_SUPPORTED_FOR_TYPE(move_iterator);
253 
254 template <class _Iter1, class _Iter2>
255 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 bool
256 operator==(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y) {
257   return __x.base() == __y.base();
258 }
259 
260 #if _LIBCPP_STD_VER <= 17
261 template <class _Iter1, class _Iter2>
262 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 bool
263 operator!=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y) {
264   return __x.base() != __y.base();
265 }
266 #endif // _LIBCPP_STD_VER <= 17
267 
268 template <class _Iter1, class _Iter2>
269 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 bool
270 operator<(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y) {
271   return __x.base() < __y.base();
272 }
273 
274 template <class _Iter1, class _Iter2>
275 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 bool
276 operator>(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y) {
277   return __x.base() > __y.base();
278 }
279 
280 template <class _Iter1, class _Iter2>
281 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 bool
282 operator<=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y) {
283   return __x.base() <= __y.base();
284 }
285 
286 template <class _Iter1, class _Iter2>
287 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 bool
288 operator>=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y) {
289   return __x.base() >= __y.base();
290 }
291 
292 #if _LIBCPP_STD_VER >= 20
293 template <class _Iter1, three_way_comparable_with<_Iter1> _Iter2>
294 inline _LIBCPP_HIDE_FROM_ABI constexpr auto
295 operator<=>(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
296     -> compare_three_way_result_t<_Iter1, _Iter2> {
297   return __x.base() <=> __y.base();
298 }
299 #endif // _LIBCPP_STD_VER >= 20
300 
301 #ifndef _LIBCPP_CXX03_LANG
302 template <class _Iter1, class _Iter2>
303 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 auto
304 operator-(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y) -> decltype(__x.base() - __y.base()) {
305   return __x.base() - __y.base();
306 }
307 #else
308 template <class _Iter1, class _Iter2>
309 inline _LIBCPP_HIDE_FROM_ABI typename move_iterator<_Iter1>::difference_type
310 operator-(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y) {
311   return __x.base() - __y.base();
312 }
313 #endif // !_LIBCPP_CXX03_LANG
314 
315 #if _LIBCPP_STD_VER >= 20
316 template <class _Iter>
317 inline _LIBCPP_HIDE_FROM_ABI constexpr move_iterator<_Iter>
318 operator+(iter_difference_t<_Iter> __n, const move_iterator<_Iter>& __x)
319   requires requires {
320     { __x.base() + __n } -> same_as<_Iter>;
321   }
322 {
323   return __x + __n;
324 }
325 #else
326 template <class _Iter>
327 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator<_Iter>
328 operator+(typename move_iterator<_Iter>::difference_type __n, const move_iterator<_Iter>& __x) {
329   return move_iterator<_Iter>(__x.base() + __n);
330 }
331 #endif // _LIBCPP_STD_VER >= 20
332 
333 template <class _Iter>
334 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX17 move_iterator<_Iter> make_move_iterator(_Iter __i) {
335   return move_iterator<_Iter>(std::move(__i));
336 }
337 
338 _LIBCPP_END_NAMESPACE_STD
339 
340 _LIBCPP_POP_MACROS
341 
342 #endif // _LIBCPP___ITERATOR_MOVE_ITERATOR_H
343