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 <__utility/move.h>
28 #include <type_traits>
29 
30 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
31 #  pragma GCC system_header
32 #endif
33 
34 _LIBCPP_BEGIN_NAMESPACE_STD
35 
36 #if _LIBCPP_STD_VER > 17
37 template<class _Iter, class = void>
38 struct __move_iter_category_base {};
39 
40 template<class _Iter>
41   requires requires { typename iterator_traits<_Iter>::iterator_category; }
42 struct __move_iter_category_base<_Iter> {
43     using iterator_category = _If<
44         derived_from<typename iterator_traits<_Iter>::iterator_category, random_access_iterator_tag>,
45         random_access_iterator_tag,
46         typename iterator_traits<_Iter>::iterator_category
47     >;
48 };
49 
50 template<class _Iter, class _Sent>
51 concept __move_iter_comparable = requires {
52     { declval<const _Iter&>() == declval<_Sent>() } -> convertible_to<bool>;
53 };
54 #endif // _LIBCPP_STD_VER > 17
55 
56 template <class _Iter>
57 class _LIBCPP_TEMPLATE_VIS move_iterator
58 #if _LIBCPP_STD_VER > 17
59     : public __move_iter_category_base<_Iter>
60 #endif
61 {
62 public:
63 #if _LIBCPP_STD_VER > 17
64     using iterator_type = _Iter;
65     using iterator_concept = input_iterator_tag;
66     // iterator_category is inherited and not always present
67     using value_type = iter_value_t<_Iter>;
68     using difference_type = iter_difference_t<_Iter>;
69     using pointer = _Iter;
70     using reference = iter_rvalue_reference_t<_Iter>;
71 #else
72     typedef _Iter iterator_type;
73     typedef _If<
74         __is_cpp17_random_access_iterator<_Iter>::value,
75         random_access_iterator_tag,
76         typename iterator_traits<_Iter>::iterator_category
77     > iterator_category;
78     typedef typename iterator_traits<iterator_type>::value_type value_type;
79     typedef typename iterator_traits<iterator_type>::difference_type difference_type;
80     typedef iterator_type pointer;
81 
82     typedef typename iterator_traits<iterator_type>::reference __reference;
83     typedef typename conditional<
84             is_reference<__reference>::value,
85             typename remove_reference<__reference>::type&&,
86             __reference
87         >::type reference;
88 #endif // _LIBCPP_STD_VER > 17
89 
90 #if _LIBCPP_STD_VER > 17
91     _LIBCPP_HIDE_FROM_ABI constexpr
92     explicit move_iterator(_Iter __i) : __current_(std::move(__i)) {}
93 
94     _LIBCPP_HIDE_FROM_ABI constexpr
95     move_iterator() requires is_constructible_v<_Iter> : __current_() {}
96 
97     template <class _Up>
98         requires (!_IsSame<_Up, _Iter>::value) && convertible_to<const _Up&, _Iter>
99     _LIBCPP_HIDE_FROM_ABI constexpr
100     move_iterator(const move_iterator<_Up>& __u) : __current_(__u.base()) {}
101 
102     template <class _Up>
103         requires (!_IsSame<_Up, _Iter>::value) &&
104                  convertible_to<const _Up&, _Iter> &&
105                  assignable_from<_Iter&, const _Up&>
106     _LIBCPP_HIDE_FROM_ABI constexpr
107     move_iterator& operator=(const move_iterator<_Up>& __u) {
108         __current_ = __u.base();
109         return *this;
110     }
111 
112     _LIBCPP_HIDE_FROM_ABI constexpr const _Iter& base() const & noexcept { return __current_; }
113     _LIBCPP_HIDE_FROM_ABI constexpr _Iter base() && { return std::move(__current_); }
114 
115     _LIBCPP_HIDE_FROM_ABI constexpr
116     reference operator*() const { return ranges::iter_move(__current_); }
117     _LIBCPP_HIDE_FROM_ABI constexpr
118     reference operator[](difference_type __n) const { return ranges::iter_move(__current_ + __n); }
119 
120     _LIBCPP_HIDE_FROM_ABI constexpr
121     move_iterator& operator++() { ++__current_; return *this; }
122 
123     _LIBCPP_HIDE_FROM_ABI constexpr
124     auto operator++(int)
125         requires forward_iterator<_Iter>
126     {
127         move_iterator __tmp(*this); ++__current_; return __tmp;
128     }
129 
130     _LIBCPP_HIDE_FROM_ABI constexpr
131     void operator++(int) { ++__current_; }
132 #else
133     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
134     explicit move_iterator(_Iter __i) : __current_(std::move(__i)) {}
135 
136     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
137     move_iterator() : __current_() {}
138 
139     template <class _Up, class = __enable_if_t<
140         !is_same<_Up, _Iter>::value && is_convertible<const _Up&, _Iter>::value
141     > >
142     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
143     move_iterator(const move_iterator<_Up>& __u) : __current_(__u.base()) {}
144 
145     template <class _Up, class = __enable_if_t<
146         !is_same<_Up, _Iter>::value &&
147         is_convertible<const _Up&, _Iter>::value &&
148         is_assignable<_Iter&, const _Up&>::value
149     > >
150     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
151     move_iterator& operator=(const move_iterator<_Up>& __u) {
152         __current_ = __u.base();
153         return *this;
154     }
155 
156     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
157     _Iter base() const { return __current_; }
158 
159     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
160     reference operator*() const { return static_cast<reference>(*__current_); }
161     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
162     pointer operator->() const { return __current_; }
163     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
164     reference operator[](difference_type __n) const { return static_cast<reference>(__current_[__n]); }
165 
166     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
167     move_iterator& operator++() { ++__current_; return *this; }
168     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
169     move_iterator operator++(int) { move_iterator __tmp(*this); ++__current_; return __tmp; }
170 #endif // _LIBCPP_STD_VER > 17
171 
172     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
173     move_iterator& operator--() { --__current_; return *this; }
174     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
175     move_iterator operator--(int) { move_iterator __tmp(*this); --__current_; return __tmp; }
176     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
177     move_iterator operator+(difference_type __n) const { return move_iterator(__current_ + __n); }
178     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
179     move_iterator& operator+=(difference_type __n) { __current_ += __n; return *this; }
180     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
181     move_iterator operator-(difference_type __n) const { return move_iterator(__current_ - __n); }
182     _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
183     move_iterator& operator-=(difference_type __n) { __current_ -= __n; return *this; }
184 
185 #if _LIBCPP_STD_VER > 17
186     template<sentinel_for<_Iter> _Sent>
187     friend _LIBCPP_HIDE_FROM_ABI constexpr
188     bool operator==(const move_iterator& __x, const move_sentinel<_Sent>& __y)
189         requires __move_iter_comparable<_Iter, _Sent>
190     {
191         return __x.base() == __y.base();
192     }
193 
194     template<sized_sentinel_for<_Iter> _Sent>
195     friend _LIBCPP_HIDE_FROM_ABI constexpr
196     iter_difference_t<_Iter> operator-(const move_sentinel<_Sent>& __x, const move_iterator& __y)
197     {
198         return __x.base() - __y.base();
199     }
200 
201     template<sized_sentinel_for<_Iter> _Sent>
202     friend _LIBCPP_HIDE_FROM_ABI constexpr
203     iter_difference_t<_Iter> operator-(const move_iterator& __x, const move_sentinel<_Sent>& __y)
204     {
205         return __x.base() - __y.base();
206     }
207 
208     friend _LIBCPP_HIDE_FROM_ABI constexpr
209     iter_rvalue_reference_t<_Iter> iter_move(const move_iterator& __i)
210         noexcept(noexcept(ranges::iter_move(__i.__current_)))
211     {
212         return ranges::iter_move(__i.__current_);
213     }
214 
215     template<indirectly_swappable<_Iter> _It2>
216     friend _LIBCPP_HIDE_FROM_ABI constexpr
217     void iter_swap(const move_iterator& __x, const move_iterator<_It2>& __y)
218         noexcept(noexcept(ranges::iter_swap(__x.__current_, __y.__current_)))
219     {
220         return ranges::iter_swap(__x.__current_, __y.__current_);
221     }
222 #endif // _LIBCPP_STD_VER > 17
223 
224 private:
225     template<class _It2> friend class move_iterator;
226 
227     _Iter __current_;
228 };
229 
230 template <class _Iter1, class _Iter2>
231 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
232 bool operator==(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
233 {
234     return __x.base() == __y.base();
235 }
236 
237 #if _LIBCPP_STD_VER <= 17
238 template <class _Iter1, class _Iter2>
239 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
240 bool operator!=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
241 {
242     return __x.base() != __y.base();
243 }
244 #endif // _LIBCPP_STD_VER <= 17
245 
246 template <class _Iter1, class _Iter2>
247 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
248 bool operator<(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
249 {
250     return __x.base() < __y.base();
251 }
252 
253 template <class _Iter1, class _Iter2>
254 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
255 bool operator>(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
256 {
257     return __x.base() > __y.base();
258 }
259 
260 template <class _Iter1, class _Iter2>
261 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
262 bool operator<=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
263 {
264     return __x.base() <= __y.base();
265 }
266 
267 template <class _Iter1, class _Iter2>
268 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
269 bool operator>=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
270 {
271     return __x.base() >= __y.base();
272 }
273 
274 #if _LIBCPP_STD_VER > 17
275 template <class _Iter1, three_way_comparable_with<_Iter1> _Iter2>
276 inline _LIBCPP_HIDE_FROM_ABI constexpr
277 auto operator<=>(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
278     -> compare_three_way_result_t<_Iter1, _Iter2>
279 {
280     return __x.base() <=> __y.base();
281 }
282 #endif // _LIBCPP_STD_VER > 17
283 
284 #ifndef _LIBCPP_CXX03_LANG
285 template <class _Iter1, class _Iter2>
286 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
287 auto operator-(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
288     -> decltype(__x.base() - __y.base())
289 {
290     return __x.base() - __y.base();
291 }
292 #else
293 template <class _Iter1, class _Iter2>
294 inline _LIBCPP_HIDE_FROM_ABI
295 typename move_iterator<_Iter1>::difference_type
296 operator-(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
297 {
298     return __x.base() - __y.base();
299 }
300 #endif // !_LIBCPP_CXX03_LANG
301 
302 #if _LIBCPP_STD_VER > 17
303 template <class _Iter>
304 inline _LIBCPP_HIDE_FROM_ABI constexpr
305 move_iterator<_Iter> operator+(iter_difference_t<_Iter> __n, const move_iterator<_Iter>& __x)
306     requires requires { { __x.base() + __n } -> same_as<_Iter>; }
307 {
308     return __x + __n;
309 }
310 #else
311 template <class _Iter>
312 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
313 move_iterator<_Iter>
314 operator+(typename move_iterator<_Iter>::difference_type __n, const move_iterator<_Iter>& __x)
315 {
316     return move_iterator<_Iter>(__x.base() + __n);
317 }
318 #endif // _LIBCPP_STD_VER > 17
319 
320 template <class _Iter>
321 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX14
322 move_iterator<_Iter>
323 make_move_iterator(_Iter __i)
324 {
325     return move_iterator<_Iter>(std::move(__i));
326 }
327 
328 _LIBCPP_END_NAMESPACE_STD
329 
330 #endif // _LIBCPP___ITERATOR_MOVE_ITERATOR_H
331