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_REVERSE_ITERATOR_H
11#define _LIBCPP___ITERATOR_REVERSE_ITERATOR_H
12
13#include <__algorithm/unwrap_iter.h>
14#include <__compare/compare_three_way_result.h>
15#include <__compare/three_way_comparable.h>
16#include <__concepts/convertible_to.h>
17#include <__config>
18#include <__iterator/concepts.h>
19#include <__iterator/incrementable_traits.h>
20#include <__iterator/iter_move.h>
21#include <__iterator/iter_swap.h>
22#include <__iterator/iterator.h>
23#include <__iterator/iterator_traits.h>
24#include <__iterator/prev.h>
25#include <__iterator/readable_traits.h>
26#include <__memory/addressof.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_LIBCPP_SUPPRESS_DEPRECATED_PUSH
37template <class _Iter>
38class _LIBCPP_TEMPLATE_VIS reverse_iterator
39#if _LIBCPP_STD_VER <= 14 || !defined(_LIBCPP_ABI_NO_ITERATOR_BASES)
40 : public iterator<typename iterator_traits<_Iter>::iterator_category,
41 typename iterator_traits<_Iter>::value_type,
42 typename iterator_traits<_Iter>::difference_type,
43 typename iterator_traits<_Iter>::pointer,
44 typename iterator_traits<_Iter>::reference>
45#endif
46{
47_LIBCPP_SUPPRESS_DEPRECATED_POP
48private:
49#ifndef _LIBCPP_ABI_NO_ITERATOR_BASES
50 _Iter __t; // no longer used as of LWG #2360, not removed due to ABI break
51#endif
52
53#if _LIBCPP_STD_VER > 17
54 static_assert(__is_cpp17_bidirectional_iterator<_Iter>::value || bidirectional_iterator<_Iter>,
55 "reverse_iterator<It> requires It to be a bidirectional iterator.");
56#endif // _LIBCPP_STD_VER > 17
57
58protected:
59 _Iter current;
60public:
61 using iterator_type = _Iter;
62
63 using iterator_category = _If<__is_cpp17_random_access_iterator<_Iter>::value,
64 random_access_iterator_tag,
65 typename iterator_traits<_Iter>::iterator_category>;
66 using pointer = typename iterator_traits<_Iter>::pointer;
67#if _LIBCPP_STD_VER > 17
68 using iterator_concept = _If<__is_cpp17_random_access_iterator<_Iter>::value,
69 random_access_iterator_tag,
70 bidirectional_iterator_tag>;
71 using value_type = iter_value_t<_Iter>;
72 using difference_type = iter_difference_t<_Iter>;
73 using reference = iter_reference_t<_Iter>;
74#else
75 using value_type = typename iterator_traits<_Iter>::value_type;
76 using difference_type = typename iterator_traits<_Iter>::difference_type;
77 using reference = typename iterator_traits<_Iter>::reference;
78#endif
79
80#ifndef _LIBCPP_ABI_NO_ITERATOR_BASES
81 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
82 reverse_iterator() : __t(), current() {}
83
84 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
85 explicit reverse_iterator(_Iter __x) : __t(__x), current(__x) {}
86
87 template <class _Up, class = __enable_if_t<
88 !is_same<_Up, _Iter>::value && is_convertible<_Up const&, _Iter>::value
89 > >
90 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
91 reverse_iterator(const reverse_iterator<_Up>& __u)
92 : __t(__u.base()), current(__u.base())
93 { }
94
95 template <class _Up, class = __enable_if_t<
96 !is_same<_Up, _Iter>::value &&
97 is_convertible<_Up const&, _Iter>::value &&
98 is_assignable<_Iter&, _Up const&>::value
99 > >
100 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
101 reverse_iterator& operator=(const reverse_iterator<_Up>& __u) {
102 __t = current = __u.base();
103 return *this;
104 }
105#else
106 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
107 reverse_iterator() : current() {}
108
109 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
110 explicit reverse_iterator(_Iter __x) : current(__x) {}
111
112 template <class _Up, class = __enable_if_t<
113 !is_same<_Up, _Iter>::value && is_convertible<_Up const&, _Iter>::value
114 > >
115 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
116 reverse_iterator(const reverse_iterator<_Up>& __u)
117 : current(__u.base())
118 { }
119
120 template <class _Up, class = __enable_if_t<
121 !is_same<_Up, _Iter>::value &&
122 is_convertible<_Up const&, _Iter>::value &&
123 is_assignable<_Iter&, _Up const&>::value
124 > >
125 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
126 reverse_iterator& operator=(const reverse_iterator<_Up>& __u) {
127 current = __u.base();
128 return *this;
129 }
130#endif
131 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
132 _Iter base() const {return current;}
133 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
134 reference operator*() const {_Iter __tmp = current; return *--__tmp;}
135
136#if _LIBCPP_STD_VER > 17
137 _LIBCPP_INLINE_VISIBILITY
138 constexpr pointer operator->() const
139 requires is_pointer_v<_Iter> || requires(const _Iter __i) { __i.operator->(); }
140 {
141 if constexpr (is_pointer_v<_Iter>) {
142 return std::prev(current);
143 } else {
144 return std::prev(current).operator->();
145 }
146 }
147#else
148 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
149 pointer operator->() const {
150 return std::addressof(operator*());
151 }
152#endif // _LIBCPP_STD_VER > 17
153
154 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
155 reverse_iterator& operator++() {--current; return *this;}
156 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
157 reverse_iterator operator++(int) {reverse_iterator __tmp(*this); --current; return __tmp;}
158 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
159 reverse_iterator& operator--() {++current; return *this;}
160 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
161 reverse_iterator operator--(int) {reverse_iterator __tmp(*this); ++current; return __tmp;}
162 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
163 reverse_iterator operator+(difference_type __n) const {return reverse_iterator(current - __n);}
164 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
165 reverse_iterator& operator+=(difference_type __n) {current -= __n; return *this;}
166 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
167 reverse_iterator operator-(difference_type __n) const {return reverse_iterator(current + __n);}
168 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
169 reverse_iterator& operator-=(difference_type __n) {current += __n; return *this;}
170 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
171 reference operator[](difference_type __n) const {return *(*this + __n);}
172
173#if _LIBCPP_STD_VER > 17
174 _LIBCPP_HIDE_FROM_ABI friend constexpr
175 iter_rvalue_reference_t<_Iter> iter_move(const reverse_iterator& __i)
176 noexcept(is_nothrow_copy_constructible_v<_Iter> &&
177 noexcept(ranges::iter_move(--declval<_Iter&>()))) {
178 auto __tmp = __i.base();
179 return ranges::iter_move(--__tmp);
180 }
181
182 template <indirectly_swappable<_Iter> _Iter2>
183 _LIBCPP_HIDE_FROM_ABI friend constexpr
184 void iter_swap(const reverse_iterator& __x, const reverse_iterator<_Iter2>& __y)
185 noexcept(is_nothrow_copy_constructible_v<_Iter> &&
186 is_nothrow_copy_constructible_v<_Iter2> &&
187 noexcept(ranges::iter_swap(--declval<_Iter&>(), --declval<_Iter2&>()))) {
188 auto __xtmp = __x.base();
189 auto __ytmp = __y.base();
190 ranges::iter_swap(--__xtmp, --__ytmp);
191 }
192#endif // _LIBCPP_STD_VER > 17
193};
194
195template <class _Iter1, class _Iter2>
196inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
197bool
198operator==(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
199#if _LIBCPP_STD_VER > 17
200 requires requires {
201 { __x.base() == __y.base() } -> convertible_to<bool>;
202 }
203#endif // _LIBCPP_STD_VER > 17
204{
205 return __x.base() == __y.base();
206}
207
208template <class _Iter1, class _Iter2>
209inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
210bool
211operator<(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
212#if _LIBCPP_STD_VER > 17
213 requires requires {
214 { __x.base() > __y.base() } -> convertible_to<bool>;
215 }
216#endif // _LIBCPP_STD_VER > 17
217{
218 return __x.base() > __y.base();
219}
220
221template <class _Iter1, class _Iter2>
222inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
223bool
224operator!=(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
225#if _LIBCPP_STD_VER > 17
226 requires requires {
227 { __x.base() != __y.base() } -> convertible_to<bool>;
228 }
229#endif // _LIBCPP_STD_VER > 17
230{
231 return __x.base() != __y.base();
232}
233
234template <class _Iter1, class _Iter2>
235inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
236bool
237operator>(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
238#if _LIBCPP_STD_VER > 17
239 requires requires {
240 { __x.base() < __y.base() } -> convertible_to<bool>;
241 }
242#endif // _LIBCPP_STD_VER > 17
243{
244 return __x.base() < __y.base();
245}
246
247template <class _Iter1, class _Iter2>
248inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
249bool
250operator>=(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
251#if _LIBCPP_STD_VER > 17
252 requires requires {
253 { __x.base() <= __y.base() } -> convertible_to<bool>;
254 }
255#endif // _LIBCPP_STD_VER > 17
256{
257 return __x.base() <= __y.base();
258}
259
260template <class _Iter1, class _Iter2>
261inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
262bool
263operator<=(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
264#if _LIBCPP_STD_VER > 17
265 requires requires {
266 { __x.base() >= __y.base() } -> convertible_to<bool>;
267 }
268#endif // _LIBCPP_STD_VER > 17
269{
270 return __x.base() >= __y.base();
271}
272
273#if _LIBCPP_STD_VER > 17
274template <class _Iter1, three_way_comparable_with<_Iter1> _Iter2>
275_LIBCPP_HIDE_FROM_ABI constexpr
276compare_three_way_result_t<_Iter1, _Iter2>
277operator<=>(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
278{
279 return __y.base() <=> __x.base();
280}
281#endif // _LIBCPP_STD_VER > 17
282
283#ifndef _LIBCPP_CXX03_LANG
284template <class _Iter1, class _Iter2>
285inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
286auto
287operator-(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
288-> decltype(__y.base() - __x.base())
289{
290 return __y.base() - __x.base();
291}
292#else
293template <class _Iter1, class _Iter2>
294inline _LIBCPP_INLINE_VISIBILITY
295typename reverse_iterator<_Iter1>::difference_type
296operator-(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
297{
298 return __y.base() - __x.base();
299}
300#endif
301
302template <class _Iter>
303inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
304reverse_iterator<_Iter>
305operator+(typename reverse_iterator<_Iter>::difference_type __n, const reverse_iterator<_Iter>& __x)
306{
307 return reverse_iterator<_Iter>(__x.base() - __n);
308}
309
310#if _LIBCPP_STD_VER > 17
311template <class _Iter1, class _Iter2>
312 requires (!sized_sentinel_for<_Iter1, _Iter2>)
313inline constexpr bool disable_sized_sentinel_for<reverse_iterator<_Iter1>, reverse_iterator<_Iter2>> = true;
314#endif // _LIBCPP_STD_VER > 17
315
316#if _LIBCPP_STD_VER > 11
317template <class _Iter>
318inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
319reverse_iterator<_Iter> make_reverse_iterator(_Iter __i)
320{
321 return reverse_iterator<_Iter>(__i);
322}
323#endif
324
325template <class _Iter>
326using _ReverseWrapper = reverse_iterator<reverse_iterator<_Iter> >;
327
328template <class _Iter, bool __b>
329struct __unwrap_iter_impl<_ReverseWrapper<_Iter>, __b> {
330 static _LIBCPP_CONSTEXPR decltype(std::__unwrap_iter(std::declval<_Iter>()))
331 __apply(_ReverseWrapper<_Iter> __i) _NOEXCEPT {
332 return std::__unwrap_iter(__i.base().base());
333 }
334};
335
336template <class _OrigIter, class _UnwrappedIter>
337struct __rewrap_iter_impl<_ReverseWrapper<_OrigIter>, _UnwrappedIter> {
338 template <class _Iter>
339 struct _ReverseWrapperCount {
340 static _LIBCPP_CONSTEXPR const size_t value = 1;
341 };
342
343 template <class _Iter>
344 struct _ReverseWrapperCount<_ReverseWrapper<_Iter> > {
345 static _LIBCPP_CONSTEXPR const size_t value = 1 + _ReverseWrapperCount<_Iter>::value;
346 };
347
348 template <size_t _RewrapCount, class _OIter, class _UIter, __enable_if_t<_RewrapCount != 0, int> = 0>
349 _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR _ReverseWrapper<_OIter> __rewrap(_ReverseWrapper<_OIter> __iter1,
350 _UIter __iter2) {
351 return _ReverseWrapper<_OIter>(
352 reverse_iterator<_OIter>(__rewrap<_RewrapCount - 1>(__iter1.base().base(), __iter2)));
353 }
354
355 template <size_t _RewrapCount, class _OIter, class _UIter, __enable_if_t<_RewrapCount == 0, int> = 0>
356 _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR decltype(std::__rewrap_iter(std::declval<_OIter>(),
357 std::declval<_UIter>()))
358 __rewrap(_OIter __iter1, _UIter __iter2) {
359 return std::__rewrap_iter(__iter1, __iter2);
360 }
361
362 _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR _ReverseWrapper<_OrigIter> __apply(_ReverseWrapper<_OrigIter> __iter1,
363 _UnwrappedIter __iter2) {
364 return __rewrap<_ReverseWrapperCount<_OrigIter>::value>(__iter1, __iter2);
365 }
366};
367
368_LIBCPP_END_NAMESPACE_STD
369
370#endif // _LIBCPP___ITERATOR_REVERSE_ITERATOR_H
371

source code of flutter_engine/third_party/libcxx/include/__iterator/reverse_iterator.h