xref: /freebsd/contrib/llvm-project/libcxx/include/iterator (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)
10b57cec5SDimitry Andric// -*- C++ -*-
2349cc55cSDimitry Andric//===----------------------------------------------------------------------===//
30b57cec5SDimitry Andric//
40b57cec5SDimitry Andric// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
50b57cec5SDimitry Andric// See https://llvm.org/LICENSE.txt for license information.
60b57cec5SDimitry Andric// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
70b57cec5SDimitry Andric//
80b57cec5SDimitry Andric//===----------------------------------------------------------------------===//
90b57cec5SDimitry Andric
100b57cec5SDimitry Andric#ifndef _LIBCPP_ITERATOR
110b57cec5SDimitry Andric#define _LIBCPP_ITERATOR
120b57cec5SDimitry Andric
130b57cec5SDimitry Andric/*
140b57cec5SDimitry Andric    iterator synopsis
150b57cec5SDimitry Andric
16fe6060f1SDimitry Andric#include <concepts>
17fe6060f1SDimitry Andric
180b57cec5SDimitry Andricnamespace std
190b57cec5SDimitry Andric{
20fe6060f1SDimitry Andrictemplate<class> struct incrementable_traits;       // since C++20
21fe6060f1SDimitry Andrictemplate<class T>
22fe6060f1SDimitry Andric  using iter_difference_t = see below;             // since C++20
23fe6060f1SDimitry Andric
24fe6060f1SDimitry Andrictemplate<class> struct indirectly_readable_traits; // since C++20
25fe6060f1SDimitry Andrictemplate<class T>
26fe6060f1SDimitry Andric  using iter_value_t = see below;                  // since C++20
270b57cec5SDimitry Andric
280b57cec5SDimitry Andrictemplate<class Iterator>
29fe6060f1SDimitry Andricstruct iterator_traits;
300b57cec5SDimitry Andric
310b57cec5SDimitry Andrictemplate<class T>
32fe6060f1SDimitry Andric  requires is_object_v<T>                    // since C++20
33fe6060f1SDimitry Andricstruct iterator_traits<T*>;
34fe6060f1SDimitry Andric
35fe6060f1SDimitry Andrictemplate<dereferenceable T>
36fe6060f1SDimitry Andric  using iter_reference_t = decltype(*declval<T&>());
37fe6060f1SDimitry Andric
38fe6060f1SDimitry Andricnamespace ranges::inline unspecified {
39fe6060f1SDimitry Andric    inline constexpr unspecified iter_move = unspecified; // since C++20, nodiscard as an extension
40fe6060f1SDimitry Andric}}
41fe6060f1SDimitry Andric
42fe6060f1SDimitry Andrictemplate<dereferenceable T>
43fe6060f1SDimitry Andric  requires ...
44fe6060f1SDimitry Andricusing iter_rvalue_reference_t = decltype(ranges::iter_move(declval<T&>())); // since C++20
45fe6060f1SDimitry Andric
46fe6060f1SDimitry Andric// [iterator.concepts], iterator concepts
47fe6060f1SDimitry Andric// [iterator.concept.readable], concept indirectly_readable
48fe6060f1SDimitry Andrictemplate<class In>
49fe6060f1SDimitry Andric  concept indirectly_readable = see below;                      // since C++20
50fe6060f1SDimitry Andric
51fe6060f1SDimitry Andrictemplate<indirectly_readable T>
52fe6060f1SDimitry Andric  using iter_common_reference_t =
53fe6060f1SDimitry Andric    common_reference_t<iter_reference_t<T>, iter_value_t<T>&>;  // since C++20
54fe6060f1SDimitry Andric
55fe6060f1SDimitry Andric// [iterator.concept.writable], concept indirectly_writable
56fe6060f1SDimitry Andrictemplate<class Out, class T>
57fe6060f1SDimitry Andric  concept indirectly_writable = see below;                // since C++20
58fe6060f1SDimitry Andric
59fe6060f1SDimitry Andric// [iterator.concept.winc], concept weakly_incrementable
60fe6060f1SDimitry Andrictemplate<class I>
61fe6060f1SDimitry Andric  concept weakly_incrementable = see below;                // since C++20
62fe6060f1SDimitry Andric
63fe6060f1SDimitry Andric// [iterator.concept.inc], concept incrementable
64fe6060f1SDimitry Andrictemplate<class I>
65fe6060f1SDimitry Andric  concept incrementable = see below;                       // since C++20
66fe6060f1SDimitry Andric
67fe6060f1SDimitry Andric// [iterator.concept.iterator], concept input_or_output_iterator
68fe6060f1SDimitry Andric  template<class I>
69fe6060f1SDimitry Andric    concept input_or_output_iterator = see below;          // since C++20
70fe6060f1SDimitry Andric
71fe6060f1SDimitry Andric// [iterator.concept.sentinel], concept sentinel_for
72fe6060f1SDimitry Andrictemplate<class S, class I>
73fe6060f1SDimitry Andric  concept sentinel_for = see below;                        // since C++20
74fe6060f1SDimitry Andric
75fe6060f1SDimitry Andric// [iterator.concept.sizedsentinel], concept sized_sentinel_for
76fe6060f1SDimitry Andrictemplate<class S, class I>
77fe6060f1SDimitry Andric  inline constexpr bool disable_sized_sentinel_for = false;
78fe6060f1SDimitry Andric
79fe6060f1SDimitry Andrictemplate<class S, class I>
80fe6060f1SDimitry Andric  concept sized_sentinel_for = see below;
81fe6060f1SDimitry Andric
82fe6060f1SDimitry Andric// [iterator.concept.input], concept input_iterator
83fe6060f1SDimitry Andrictemplate<class I>
84fe6060f1SDimitry Andric  concept input_iterator = see below;                      // since C++20
85fe6060f1SDimitry Andric
86fe6060f1SDimitry Andric// [iterator.concept.output], concept output_iterator
87fe6060f1SDimitry Andrictemplate<class I, class T>
88fe6060f1SDimitry Andric  concept output_iterator = see below;                     // since C++20
89fe6060f1SDimitry Andric
90fe6060f1SDimitry Andric// [iterator.concept.forward], concept forward_iterator
91fe6060f1SDimitry Andrictemplate<class I>
92fe6060f1SDimitry Andric  concept forward_iterator = see below;                    // since C++20
93fe6060f1SDimitry Andric
94fe6060f1SDimitry Andric// [iterator.concept.bidir], concept bidirectional_iterator
95fe6060f1SDimitry Andrictemplate<class I>
96fe6060f1SDimitry Andric  concept bidirectional_iterator = see below;              // since C++20
97fe6060f1SDimitry Andric
98fe6060f1SDimitry Andric// [iterator.concept.random.access], concept random_access_iterator
99fe6060f1SDimitry Andrictemplate<class I>
100fe6060f1SDimitry Andric  concept random_access_iterator = see below;              // since C++20
101fe6060f1SDimitry Andric
102fe6060f1SDimitry Andric// [indirectcallable]
103fe6060f1SDimitry Andric// [indirectcallable.indirectinvocable]
104fe6060f1SDimitry Andrictemplate<class F, class I>
105fe6060f1SDimitry Andric  concept indirectly_unary_invocable = see below;          // since C++20
106fe6060f1SDimitry Andric
107fe6060f1SDimitry Andrictemplate<class F, class I>
108fe6060f1SDimitry Andric  concept indirectly_regular_unary_invocable = see below;  // since C++20
109fe6060f1SDimitry Andric
110fe6060f1SDimitry Andrictemplate<class F, class I>
111fe6060f1SDimitry Andric  concept indirect_unary_predicate = see below;            // since C++20
112fe6060f1SDimitry Andric
113fe6060f1SDimitry Andrictemplate<class F, class I1, class I2>
114fe6060f1SDimitry Andric  concept indirect_binary_predicate = see below;           // since C++20
115fe6060f1SDimitry Andric
116fe6060f1SDimitry Andrictemplate<class F, class I1, class I2 = I1>
117fe6060f1SDimitry Andric  concept indirect_equivalence_relation = see below;       // since C++20
118fe6060f1SDimitry Andric
119fe6060f1SDimitry Andrictemplate<class F, class I1, class I2 = I1>
120fe6060f1SDimitry Andric  concept indirect_strict_weak_order = see below;          // since C++20
121fe6060f1SDimitry Andric
122fe6060f1SDimitry Andrictemplate<class F, class... Is>
123fe6060f1SDimitry Andric  using indirect_result_t = see below;                     // since C++20
124fe6060f1SDimitry Andric
125fe6060f1SDimitry Andric// [projected], projected
126fe6060f1SDimitry Andrictemplate<indirectly_readable I, indirectly_regular_unary_invocable<I> Proj>
127fe6060f1SDimitry Andric  struct projected;                                        // since C++20
128fe6060f1SDimitry Andric
129fe6060f1SDimitry Andrictemplate<weakly_incrementable I, indirectly_regular_unary_invocable<I> Proj>
130fe6060f1SDimitry Andric  struct incrementable_traits<projected<I, Proj>>;         // since C++20
131fe6060f1SDimitry Andric
132fe6060f1SDimitry Andric// [alg.req.ind.move], concept indirectly_movable
133fe6060f1SDimitry Andrictemplate<class In, class Out>
134fe6060f1SDimitry Andric  concept indirectly_movable = see below;                  // since C++20
135fe6060f1SDimitry Andric
136fe6060f1SDimitry Andrictemplate<class In, class Out>
137fe6060f1SDimitry Andric  concept indirectly_movable_storable = see below;         // since C++20
138fe6060f1SDimitry Andric
13981ad6265SDimitry Andric// [alg.req.ind.copy], concept indirectly_copyable
14081ad6265SDimitry Andrictemplate<class In, class Out>
14181ad6265SDimitry Andric  concept indirectly_copyable = see below;                 // since C++20
14281ad6265SDimitry Andric
14381ad6265SDimitry Andrictemplate<class In, class Out>
14481ad6265SDimitry Andric  concept indirectly_copyable_storable = see below;        // since C++20
14581ad6265SDimitry Andric
146fe6060f1SDimitry Andric// [alg.req.ind.swap], concept indirectly_swappable
147fe6060f1SDimitry Andrictemplate<class I1, class I2 = I1>
148fe6060f1SDimitry Andric  concept indirectly_swappable = see below;                // since C++20
149fe6060f1SDimitry Andric
15004eeddc0SDimitry Andrictemplate<class I1, class I2, class R, class P1 = identity,
15104eeddc0SDimitry Andric         class P2 = identity>
15204eeddc0SDimitry Andric  concept indirectly_comparable =
15304eeddc0SDimitry Andric    indirect_binary_predicate<R, projected<I1, P1>, projected<I2, P2>>; // since C++20
15404eeddc0SDimitry Andric
15581ad6265SDimitry Andric// [alg.req.permutable], concept permutable
15681ad6265SDimitry Andrictemplate<class I>
15781ad6265SDimitry Andric  concept permutable = see below;                          // since C++20
15881ad6265SDimitry Andric
15981ad6265SDimitry Andric // [alg.req.mergeable], concept mergeable
16081ad6265SDimitry Andrictemplate<class I1, class I2, class Out,
16181ad6265SDimitry Andric    class R = ranges::less, class P1 = identity, class P2 = identity>
16281ad6265SDimitry Andric  concept mergeable = see below;                           // since C++20
16381ad6265SDimitry Andric
16481ad6265SDimitry Andric// [alg.req.sortable], concept sortable
16581ad6265SDimitry Andrictemplate<class I, class R = ranges::less, class P = identity>
16681ad6265SDimitry Andric  concept sortable = see below;                            // since C++20
16781ad6265SDimitry Andric
168fe6060f1SDimitry Andrictemplate<input_or_output_iterator I, sentinel_for<I> S>
169fe6060f1SDimitry Andric  requires (!same_as<I, S> && copyable<I>)
170fe6060f1SDimitry Andricclass common_iterator;                                     // since C++20
1710b57cec5SDimitry Andric
1720b57cec5SDimitry Andrictemplate<class Category, class T, class Distance = ptrdiff_t,
1730b57cec5SDimitry Andric         class Pointer = T*, class Reference = T&>
174fe6060f1SDimitry Andricstruct iterator                                            // deprecated in C++17
1750b57cec5SDimitry Andric{
1760b57cec5SDimitry Andric    typedef T         value_type;
1770b57cec5SDimitry Andric    typedef Distance  difference_type;
1780b57cec5SDimitry Andric    typedef Pointer   pointer;
1790b57cec5SDimitry Andric    typedef Reference reference;
1800b57cec5SDimitry Andric    typedef Category  iterator_category;
1810b57cec5SDimitry Andric};
1820b57cec5SDimitry Andric
1830b57cec5SDimitry Andricstruct input_iterator_tag  {};
1840b57cec5SDimitry Andricstruct output_iterator_tag {};
1850b57cec5SDimitry Andricstruct forward_iterator_tag       : public input_iterator_tag         {};
1860b57cec5SDimitry Andricstruct bidirectional_iterator_tag : public forward_iterator_tag       {};
1870b57cec5SDimitry Andricstruct random_access_iterator_tag : public bidirectional_iterator_tag {};
18881ad6265SDimitry Andricstruct contiguous_iterator_tag    : public random_access_iterator_tag {};
1890b57cec5SDimitry Andric
1900b57cec5SDimitry Andric// 27.4.3, iterator operations
1915ffd83dbSDimitry Andrictemplate <class InputIterator, class Distance>  // constexpr in C++17
1925ffd83dbSDimitry Andric  constexpr void advance(InputIterator& i, Distance n);
1930b57cec5SDimitry Andric
1940b57cec5SDimitry Andrictemplate <class InputIterator>  // constexpr in C++17
1950b57cec5SDimitry Andric  constexpr typename iterator_traits<InputIterator>::difference_type
1960b57cec5SDimitry Andric    distance(InputIterator first, InputIterator last);
1970b57cec5SDimitry Andric
1980b57cec5SDimitry Andrictemplate <class InputIterator>  // constexpr in C++17
1990b57cec5SDimitry Andric  constexpr InputIterator next(InputIterator x,
2000b57cec5SDimitry Andrictypename iterator_traits<InputIterator>::difference_type n = 1);
2010b57cec5SDimitry Andric
2020b57cec5SDimitry Andrictemplate <class BidirectionalIterator>  // constexpr in C++17
2030b57cec5SDimitry Andric  constexpr BidirectionalIterator prev(BidirectionalIterator x,
2040b57cec5SDimitry Andric    typename iterator_traits<BidirectionalIterator>::difference_type n = 1);
2050b57cec5SDimitry Andric
206fe6060f1SDimitry Andric// [range.iter.ops], range iterator operations
207fe6060f1SDimitry Andricnamespace ranges {
208fe6060f1SDimitry Andric  // [range.iter.op.advance], ranges::advance
209fe6060f1SDimitry Andric  template<input_or_output_iterator I>
210fe6060f1SDimitry Andric    constexpr void advance(I& i, iter_difference_t<I> n);                          // since C++20
211fe6060f1SDimitry Andric  template<input_or_output_iterator I, sentinel_for<I> S>
212fe6060f1SDimitry Andric    constexpr void advance(I& i, S bound);                                         // since C++20
213fe6060f1SDimitry Andric  template<input_or_output_iterator I, sentinel_for<I> S>
214fe6060f1SDimitry Andric    constexpr iter_difference_t<I> advance(I& i, iter_difference_t<I> n, S bound); // since C++20
215fe6060f1SDimitry Andric}
216fe6060f1SDimitry Andric
2170b57cec5SDimitry Andrictemplate <class Iterator>
2180b57cec5SDimitry Andricclass reverse_iterator
219fe6060f1SDimitry Andric    : public iterator<typename iterator_traits<Iterator>::iterator_category, // until C++17
2200b57cec5SDimitry Andric                      typename iterator_traits<Iterator>::value_type,
2210b57cec5SDimitry Andric                      typename iterator_traits<Iterator>::difference_type,
2220b57cec5SDimitry Andric                      typename iterator_traits<Iterator>::pointer,
2230b57cec5SDimitry Andric                      typename iterator_traits<Iterator>::reference>
2240b57cec5SDimitry Andric{
2250b57cec5SDimitry Andricprotected:
2260b57cec5SDimitry Andric    Iterator current;
2270b57cec5SDimitry Andricpublic:
22881ad6265SDimitry Andric    using iterator_type     = Iterator;
22981ad6265SDimitry Andric    using iterator_concept  = see below; // since C++20
23081ad6265SDimitry Andric    using iterator_category = typename iterator_traits<Iterator>::iterator_category; // since C++17, until C++20
23181ad6265SDimitry Andric    using iterator_category = see below; // since C++20
23281ad6265SDimitry Andric    using value_type        = typename iterator_traits<Iterator>::value_type; // since C++17, until C++20
23381ad6265SDimitry Andric    using value_type        = iter_value_t<Iterator>; // since C++20
23481ad6265SDimitry Andric    using difference_type   = typename iterator_traits<Iterator>::difference_type; // until C++20
23581ad6265SDimitry Andric    using difference_type   = iter_difference_t<Iterator>; // since C++20
23681ad6265SDimitry Andric    using pointer           = typename iterator_traits<Iterator>::pointer;
23781ad6265SDimitry Andric    using reference         = typename iterator_traits<Iterator>::reference; // until C++20
23881ad6265SDimitry Andric    using reference         = iter_reference_t<Iterator>; // since C++20
2390b57cec5SDimitry Andric
2400b57cec5SDimitry Andric    constexpr reverse_iterator();
2410b57cec5SDimitry Andric    constexpr explicit reverse_iterator(Iterator x);
2420b57cec5SDimitry Andric    template <class U> constexpr reverse_iterator(const reverse_iterator<U>& u);
2430b57cec5SDimitry Andric    template <class U> constexpr reverse_iterator& operator=(const reverse_iterator<U>& u);
2440b57cec5SDimitry Andric    constexpr Iterator base() const;
2450b57cec5SDimitry Andric    constexpr reference operator*() const;
24681ad6265SDimitry Andric    constexpr pointer   operator->() const; // until C++20
24781ad6265SDimitry Andric    constexpr pointer   operator->() const requires see below; // since C++20
2480b57cec5SDimitry Andric    constexpr reverse_iterator& operator++();
2490b57cec5SDimitry Andric    constexpr reverse_iterator  operator++(int);
2500b57cec5SDimitry Andric    constexpr reverse_iterator& operator--();
2510b57cec5SDimitry Andric    constexpr reverse_iterator  operator--(int);
2520b57cec5SDimitry Andric    constexpr reverse_iterator  operator+ (difference_type n) const;
2530b57cec5SDimitry Andric    constexpr reverse_iterator& operator+=(difference_type n);
2540b57cec5SDimitry Andric    constexpr reverse_iterator  operator- (difference_type n) const;
2550b57cec5SDimitry Andric    constexpr reverse_iterator& operator-=(difference_type n);
25681ad6265SDimitry Andric    constexpr unspecified       operator[](difference_type n) const;
25781ad6265SDimitry Andric
25881ad6265SDimitry Andric    friend constexpr iter_rvalue_reference_t<Iterator>
25981ad6265SDimitry Andric      iter_move(const reverse_iterator& i) noexcept(see below);
26081ad6265SDimitry Andric    template<indirectly_swappable<Iterator> Iterator2>
26181ad6265SDimitry Andric      friend constexpr void
26281ad6265SDimitry Andric        iter_swap(const reverse_iterator& x,
26381ad6265SDimitry Andric                  const reverse_iterator<Iterator2>& y) noexcept(see below);
2640b57cec5SDimitry Andric};
2650b57cec5SDimitry Andric
2660b57cec5SDimitry Andrictemplate <class Iterator1, class Iterator2>
2670b57cec5SDimitry Andricconstexpr bool                          // constexpr in C++17
2680b57cec5SDimitry Andricoperator==(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
2690b57cec5SDimitry Andric
2700b57cec5SDimitry Andrictemplate <class Iterator1, class Iterator2>
2710b57cec5SDimitry Andricconstexpr bool                          // constexpr in C++17
27281ad6265SDimitry Andricoperator!=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
2730b57cec5SDimitry Andric
2740b57cec5SDimitry Andrictemplate <class Iterator1, class Iterator2>
2750b57cec5SDimitry Andricconstexpr bool                          // constexpr in C++17
27681ad6265SDimitry Andricoperator<(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
2770b57cec5SDimitry Andric
2780b57cec5SDimitry Andrictemplate <class Iterator1, class Iterator2>
2790b57cec5SDimitry Andricconstexpr bool                          // constexpr in C++17
2800b57cec5SDimitry Andricoperator>(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
2810b57cec5SDimitry Andric
2820b57cec5SDimitry Andrictemplate <class Iterator1, class Iterator2>
2830b57cec5SDimitry Andricconstexpr bool                          // constexpr in C++17
28481ad6265SDimitry Andricoperator<=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
2850b57cec5SDimitry Andric
2860b57cec5SDimitry Andrictemplate <class Iterator1, class Iterator2>
2870b57cec5SDimitry Andricconstexpr bool                          // constexpr in C++17
28881ad6265SDimitry Andricoperator>=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
28981ad6265SDimitry Andric
29081ad6265SDimitry Andrictemplate<class Iterator1, three_way_comparable_with<Iterator1> Iterator2>
29181ad6265SDimitry Andric  constexpr compare_three_way_result_t<Iterator1, Iterator2>
29281ad6265SDimitry Andric    operator<=>(const reverse_iterator<Iterator1>& x,
29381ad6265SDimitry Andric                const reverse_iterator<Iterator2>& y);
2940b57cec5SDimitry Andric
2950b57cec5SDimitry Andrictemplate <class Iterator1, class Iterator2>
2960b57cec5SDimitry Andricconstexpr auto
2970b57cec5SDimitry Andricoperator-(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y)
2980b57cec5SDimitry Andric-> decltype(__y.base() - __x.base());   // constexpr in C++17
2990b57cec5SDimitry Andric
3000b57cec5SDimitry Andrictemplate <class Iterator>
3010b57cec5SDimitry Andricconstexpr reverse_iterator<Iterator>
3020b57cec5SDimitry Andricoperator+(typename reverse_iterator<Iterator>::difference_type n,
3030b57cec5SDimitry Andric          const reverse_iterator<Iterator>& x);   // constexpr in C++17
3040b57cec5SDimitry Andric
3050b57cec5SDimitry Andrictemplate <class Iterator>
3060b57cec5SDimitry Andricconstexpr reverse_iterator<Iterator> make_reverse_iterator(Iterator i); // C++14, constexpr in C++17
3070b57cec5SDimitry Andric
30881ad6265SDimitry Andrictemplate<class Iterator1, class Iterator2>
30981ad6265SDimitry Andric    requires (!sized_sentinel_for<Iterator1, Iterator2>)
31081ad6265SDimitry Andric  inline constexpr bool disable_sized_sentinel_for<reverse_iterator<Iterator1>,
31181ad6265SDimitry Andric                                                   reverse_iterator<Iterator2>> = true;
31281ad6265SDimitry Andric
3130b57cec5SDimitry Andrictemplate <class Container>
3140b57cec5SDimitry Andricclass back_insert_iterator
315fe6060f1SDimitry Andric    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
3160b57cec5SDimitry Andric{
3170b57cec5SDimitry Andricprotected:
3180b57cec5SDimitry Andric    Container* container;
3190b57cec5SDimitry Andricpublic:
3200b57cec5SDimitry Andric    typedef Container                   container_type;
3210b57cec5SDimitry Andric    typedef void                        value_type;
322fe6060f1SDimitry Andric    typedef void                        difference_type; // until C++20
323fe6060f1SDimitry Andric    typedef ptrdiff_t                   difference_type; // since C++20
3240b57cec5SDimitry Andric    typedef void                        reference;
3250b57cec5SDimitry Andric    typedef void                        pointer;
3260b57cec5SDimitry Andric
327fe6060f1SDimitry Andric    explicit back_insert_iterator(Container& x);  // constexpr in C++20
328fe6060f1SDimitry Andric    back_insert_iterator& operator=(const typename Container::value_type& value);  // constexpr in C++20
329fe6060f1SDimitry Andric    back_insert_iterator& operator*();  // constexpr in C++20
330fe6060f1SDimitry Andric    back_insert_iterator& operator++();  // constexpr in C++20
331fe6060f1SDimitry Andric    back_insert_iterator  operator++(int);  // constexpr in C++20
3320b57cec5SDimitry Andric};
3330b57cec5SDimitry Andric
334fe6060f1SDimitry Andrictemplate <class Container> back_insert_iterator<Container> back_inserter(Container& x);  // constexpr in C++20
3350b57cec5SDimitry Andric
3360b57cec5SDimitry Andrictemplate <class Container>
3370b57cec5SDimitry Andricclass front_insert_iterator
338fe6060f1SDimitry Andric    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
3390b57cec5SDimitry Andric{
3400b57cec5SDimitry Andricprotected:
3410b57cec5SDimitry Andric    Container* container;
3420b57cec5SDimitry Andricpublic:
3430b57cec5SDimitry Andric    typedef Container                    container_type;
3440b57cec5SDimitry Andric    typedef void                         value_type;
345fe6060f1SDimitry Andric    typedef void                         difference_type; // until C++20
346fe6060f1SDimitry Andric    typedef ptrdiff_t                    difference_type; // since C++20
3470b57cec5SDimitry Andric    typedef void                         reference;
3480b57cec5SDimitry Andric    typedef void                         pointer;
3490b57cec5SDimitry Andric
350fe6060f1SDimitry Andric    explicit front_insert_iterator(Container& x);  // constexpr in C++20
351fe6060f1SDimitry Andric    front_insert_iterator& operator=(const typename Container::value_type& value);  // constexpr in C++20
352fe6060f1SDimitry Andric    front_insert_iterator& operator*();  // constexpr in C++20
353fe6060f1SDimitry Andric    front_insert_iterator& operator++();  // constexpr in C++20
354fe6060f1SDimitry Andric    front_insert_iterator  operator++(int);  // constexpr in C++20
3550b57cec5SDimitry Andric};
3560b57cec5SDimitry Andric
357fe6060f1SDimitry Andrictemplate <class Container> front_insert_iterator<Container> front_inserter(Container& x);  // constexpr in C++20
3580b57cec5SDimitry Andric
3590b57cec5SDimitry Andrictemplate <class Container>
3600b57cec5SDimitry Andricclass insert_iterator
361fe6060f1SDimitry Andric    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
3620b57cec5SDimitry Andric{
3630b57cec5SDimitry Andricprotected:
3640b57cec5SDimitry Andric    Container* container;
3650b57cec5SDimitry Andric    typename Container::iterator iter;
3660b57cec5SDimitry Andricpublic:
3670b57cec5SDimitry Andric    typedef Container              container_type;
3680b57cec5SDimitry Andric    typedef void                   value_type;
369fe6060f1SDimitry Andric    typedef void                   difference_type; // until C++20
370fe6060f1SDimitry Andric    typedef ptrdiff_t              difference_type; // since C++20
3710b57cec5SDimitry Andric    typedef void                   reference;
3720b57cec5SDimitry Andric    typedef void                   pointer;
3730b57cec5SDimitry Andric
374fe6060f1SDimitry Andric    insert_iterator(Container& x, typename Container::iterator i);  // constexpr in C++20
375fe6060f1SDimitry Andric    insert_iterator& operator=(const typename Container::value_type& value);  // constexpr in C++20
376fe6060f1SDimitry Andric    insert_iterator& operator*();  // constexpr in C++20
377fe6060f1SDimitry Andric    insert_iterator& operator++();  // constexpr in C++20
378fe6060f1SDimitry Andric    insert_iterator& operator++(int);  // constexpr in C++20
3790b57cec5SDimitry Andric};
3800b57cec5SDimitry Andric
38181ad6265SDimitry Andrictemplate <class Container>
38281ad6265SDimitry Andricinsert_iterator<Container> inserter(Container& x, typename Container::iterator i);  // until C++20
38381ad6265SDimitry Andrictemplate <class Container>
38481ad6265SDimitry Andricconstexpr insert_iterator<Container> inserter(Container& x, ranges::iterator_t<Container> i);  // since C++20
3850b57cec5SDimitry Andric
3860b57cec5SDimitry Andrictemplate <class Iterator>
3870b57cec5SDimitry Andricclass move_iterator {
3880b57cec5SDimitry Andricpublic:
38981ad6265SDimitry Andric    using iterator_type     = Iterator;
39006c3fb27SDimitry Andric    using iterator_concept  = see below; // From C++20
39181ad6265SDimitry Andric    using iterator_category = see below; // not always present starting from C++20
39281ad6265SDimitry Andric    using value_type        = iter_value_t<Iterator>; // Until C++20, iterator_traits<Iterator>::value_type
39381ad6265SDimitry Andric    using difference_type   = iter_difference_t<Iterator>; // Until C++20, iterator_traits<Iterator>::difference_type;
39481ad6265SDimitry Andric    using pointer           = Iterator;
39581ad6265SDimitry Andric    using reference         = iter_rvalue_reference_t<Iterator>; // Until C++20, value_type&&
3960b57cec5SDimitry Andric
3970b57cec5SDimitry Andric    constexpr move_iterator();  // all the constexprs are in C++17
3980b57cec5SDimitry Andric    constexpr explicit move_iterator(Iterator i);
3990b57cec5SDimitry Andric    template <class U>
4000b57cec5SDimitry Andric      constexpr move_iterator(const move_iterator<U>& u);
4010b57cec5SDimitry Andric    template <class U>
4020b57cec5SDimitry Andric      constexpr move_iterator& operator=(const move_iterator<U>& u);
40381ad6265SDimitry Andric
40481ad6265SDimitry Andric    constexpr iterator_type base() const; // Until C++20
40581ad6265SDimitry Andric    constexpr const Iterator& base() const & noexcept; // From C++20
40681ad6265SDimitry Andric    constexpr Iterator base() &&; // From C++20
40781ad6265SDimitry Andric
4080b57cec5SDimitry Andric    constexpr reference operator*() const;
40981ad6265SDimitry Andric    constexpr pointer operator->() const; // Deprecated in C++20
4100b57cec5SDimitry Andric    constexpr move_iterator& operator++();
41181ad6265SDimitry Andric    constexpr auto operator++(int); // Return type was move_iterator until C++20
4120b57cec5SDimitry Andric    constexpr move_iterator& operator--();
4130b57cec5SDimitry Andric    constexpr move_iterator operator--(int);
4140b57cec5SDimitry Andric    constexpr move_iterator operator+(difference_type n) const;
4150b57cec5SDimitry Andric    constexpr move_iterator& operator+=(difference_type n);
4160b57cec5SDimitry Andric    constexpr move_iterator operator-(difference_type n) const;
4170b57cec5SDimitry Andric    constexpr move_iterator& operator-=(difference_type n);
41881ad6265SDimitry Andric    constexpr reference operator[](difference_type n) const; // Return type unspecified until C++20
41981ad6265SDimitry Andric
42081ad6265SDimitry Andric    template<sentinel_for<Iterator> S>
42181ad6265SDimitry Andric      friend constexpr bool
42281ad6265SDimitry Andric        operator==(const move_iterator& x, const move_sentinel<S>& y); // Since C++20
42381ad6265SDimitry Andric    template<sized_sentinel_for<Iterator> S>
42481ad6265SDimitry Andric      friend constexpr iter_difference_t<Iterator>
42581ad6265SDimitry Andric        operator-(const move_sentinel<S>& x, const move_iterator& y); // Since C++20
42681ad6265SDimitry Andric    template<sized_sentinel_for<Iterator> S>
42781ad6265SDimitry Andric      friend constexpr iter_difference_t<Iterator>
42881ad6265SDimitry Andric        operator-(const move_iterator& x, const move_sentinel<S>& y); // Since C++20
42981ad6265SDimitry Andric    friend constexpr iter_rvalue_reference_t<Iterator>
43081ad6265SDimitry Andric      iter_move(const move_iterator& i)
43181ad6265SDimitry Andric        noexcept(noexcept(ranges::iter_move(i.current))); // Since C++20
43281ad6265SDimitry Andric    template<indirectly_swappable<Iterator> Iterator2>
43381ad6265SDimitry Andric      friend constexpr void
43481ad6265SDimitry Andric        iter_swap(const move_iterator& x, const move_iterator<Iterator2>& y)
43581ad6265SDimitry Andric          noexcept(noexcept(ranges::iter_swap(x.current, y.current))); // Since C++20
43681ad6265SDimitry Andric
4370b57cec5SDimitry Andricprivate:
4380b57cec5SDimitry Andric    Iterator current; // exposition only
4390b57cec5SDimitry Andric};
4400b57cec5SDimitry Andric
4410b57cec5SDimitry Andrictemplate <class Iterator1, class Iterator2>
4420b57cec5SDimitry Andricconstexpr bool   // constexpr in C++17
4430b57cec5SDimitry Andricoperator==(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
4440b57cec5SDimitry Andric
4450b57cec5SDimitry Andrictemplate <class Iterator1, class Iterator2>
4460b57cec5SDimitry Andricconstexpr bool   // constexpr in C++17
4470b57cec5SDimitry Andricoperator!=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
4480b57cec5SDimitry Andric
4490b57cec5SDimitry Andrictemplate <class Iterator1, class Iterator2>
4500b57cec5SDimitry Andricconstexpr bool   // constexpr in C++17
4510b57cec5SDimitry Andricoperator<(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
4520b57cec5SDimitry Andric
4530b57cec5SDimitry Andrictemplate <class Iterator1, class Iterator2>
4540b57cec5SDimitry Andricconstexpr bool   // constexpr in C++17
4550b57cec5SDimitry Andricoperator<=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
4560b57cec5SDimitry Andric
4570b57cec5SDimitry Andrictemplate <class Iterator1, class Iterator2>
4580b57cec5SDimitry Andricconstexpr bool   // constexpr in C++17
4590b57cec5SDimitry Andricoperator>(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
4600b57cec5SDimitry Andric
4610b57cec5SDimitry Andrictemplate <class Iterator1, class Iterator2>
4620b57cec5SDimitry Andricconstexpr bool   // constexpr in C++17
4630b57cec5SDimitry Andricoperator>=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
4640b57cec5SDimitry Andric
4650b57cec5SDimitry Andrictemplate <class Iterator1, class Iterator2>
4660b57cec5SDimitry Andricconstexpr auto   // constexpr in C++17
4670b57cec5SDimitry Andricoperator-(const move_iterator<Iterator1>& x,
4680b57cec5SDimitry Andric          const move_iterator<Iterator2>& y) -> decltype(x.base() - y.base());
4690b57cec5SDimitry Andric
4700b57cec5SDimitry Andrictemplate <class Iterator>
4710b57cec5SDimitry Andricconstexpr move_iterator<Iterator> operator+(   // constexpr in C++17
4720b57cec5SDimitry Andric            typename move_iterator<Iterator>::difference_type n,
4730b57cec5SDimitry Andric            const move_iterator<Iterator>& x);
4740b57cec5SDimitry Andric
4750b57cec5SDimitry Andrictemplate <class Iterator>   // constexpr in C++17
4760b57cec5SDimitry Andricconstexpr  move_iterator<Iterator> make_move_iterator(const Iterator& i);
4770b57cec5SDimitry Andric
478*0fca6ea1SDimitry Andrictemplate<class Iterator1, class Iterator2>
479*0fca6ea1SDimitry Andric    requires (!sized_sentinel_for<Iterator1, Iterator2>)
480*0fca6ea1SDimitry Andric  inline constexpr bool disable_sized_sentinel_for<move_iterator<Iterator1>,    // since C++20
481*0fca6ea1SDimitry Andric                                                    move_iterator<Iterator2>> = true;
482*0fca6ea1SDimitry Andric
48381ad6265SDimitry Andrictemplate<semiregular S>
48481ad6265SDimitry Andricclass move_sentinel {
48581ad6265SDimitry Andricpublic:
48681ad6265SDimitry Andric  constexpr move_sentinel();
48781ad6265SDimitry Andric  constexpr explicit move_sentinel(S s);
48881ad6265SDimitry Andric  template<class S2>
48981ad6265SDimitry Andric    requires convertible_to<const S2&, S>
49081ad6265SDimitry Andric      constexpr move_sentinel(const move_sentinel<S2>& s);
49181ad6265SDimitry Andric  template<class S2>
49281ad6265SDimitry Andric    requires assignable_from<S&, const S2&>
49381ad6265SDimitry Andric      constexpr move_sentinel& operator=(const move_sentinel<S2>& s);
49481ad6265SDimitry Andric
49581ad6265SDimitry Andric  constexpr S base() const;
49681ad6265SDimitry Andricprivate:
49781ad6265SDimitry Andric  S last;     // exposition only
49881ad6265SDimitry Andric};
49981ad6265SDimitry Andric
500fe6060f1SDimitry Andric// [default.sentinel], default sentinel
501fe6060f1SDimitry Andricstruct default_sentinel_t;
502fe6060f1SDimitry Andricinline constexpr default_sentinel_t default_sentinel{};
503fe6060f1SDimitry Andric
504fe6060f1SDimitry Andric// [iterators.counted], counted iterators
505fe6060f1SDimitry Andrictemplate<input_or_output_iterator I> class counted_iterator;
506fe6060f1SDimitry Andric
507fe6060f1SDimitry Andrictemplate<input_iterator I>
508fe6060f1SDimitry Andric  requires see below
509fe6060f1SDimitry Andric  struct iterator_traits<counted_iterator<I>>;
5100b57cec5SDimitry Andric
511349cc55cSDimitry Andric// [unreachable.sentinel], unreachable sentinel
512349cc55cSDimitry Andricstruct unreachable_sentinel_t;
513349cc55cSDimitry Andricinline constexpr unreachable_sentinel_t unreachable_sentinel{};
514349cc55cSDimitry Andric
5150b57cec5SDimitry Andrictemplate <class T, class charT = char, class traits = char_traits<charT>, class Distance = ptrdiff_t>
5160b57cec5SDimitry Andricclass istream_iterator
517fe6060f1SDimitry Andric    : public iterator<input_iterator_tag, T, Distance, const T*, const T&> // until C++17
5180b57cec5SDimitry Andric{
5190b57cec5SDimitry Andricpublic:
520fe6060f1SDimitry Andric    typedef input_iterator_tag           iterator_category;
521fe6060f1SDimitry Andric    typedef T                            value_type;
522fe6060f1SDimitry Andric    typedef Distance                     difference_type;
523fe6060f1SDimitry Andric    typedef const T*                     pointer;
524fe6060f1SDimitry Andric    typedef const T&                     reference;
525fe6060f1SDimitry Andric
5260b57cec5SDimitry Andric    typedef charT                        char_type;
5270b57cec5SDimitry Andric    typedef traits                       traits_type;
5280b57cec5SDimitry Andric    typedef basic_istream<charT, traits> istream_type;
5290b57cec5SDimitry Andric
53081ad6265SDimitry Andric    istream_iterator(); // constexpr since C++11
53181ad6265SDimitry Andric    constexpr istream_iterator(default_sentinel_t); // since C++20
5320b57cec5SDimitry Andric    istream_iterator(istream_type& s);
5330b57cec5SDimitry Andric    istream_iterator(const istream_iterator& x);
5340b57cec5SDimitry Andric    ~istream_iterator();
5350b57cec5SDimitry Andric
5360b57cec5SDimitry Andric    const T& operator*() const;
5370b57cec5SDimitry Andric    const T* operator->() const;
5380b57cec5SDimitry Andric    istream_iterator& operator++();
5390b57cec5SDimitry Andric    istream_iterator  operator++(int);
54081ad6265SDimitry Andric    friend bool operator==(const istream_iterator& i, default_sentinel_t); // since C++20
5410b57cec5SDimitry Andric};
5420b57cec5SDimitry Andric
5430b57cec5SDimitry Andrictemplate <class T, class charT, class traits, class Distance>
5440b57cec5SDimitry Andricbool operator==(const istream_iterator<T,charT,traits,Distance>& x,
5450b57cec5SDimitry Andric                const istream_iterator<T,charT,traits,Distance>& y);
5460b57cec5SDimitry Andrictemplate <class T, class charT, class traits, class Distance>
5470b57cec5SDimitry Andricbool operator!=(const istream_iterator<T,charT,traits,Distance>& x,
54881ad6265SDimitry Andric                const istream_iterator<T,charT,traits,Distance>& y); // until C++20
5490b57cec5SDimitry Andric
5500b57cec5SDimitry Andrictemplate <class T, class charT = char, class traits = char_traits<charT> >
5510b57cec5SDimitry Andricclass ostream_iterator
552fe6060f1SDimitry Andric    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
5530b57cec5SDimitry Andric{
5540b57cec5SDimitry Andricpublic:
555fe6060f1SDimitry Andric    typedef output_iterator_tag         iterator_category;
556fe6060f1SDimitry Andric    typedef void                        value_type;
557fe6060f1SDimitry Andric    typedef void                        difference_type; // until C++20
558fe6060f1SDimitry Andric    typedef ptrdiff_t                   difference_type; // since C++20
559fe6060f1SDimitry Andric    typedef void                        pointer;
560fe6060f1SDimitry Andric    typedef void                        reference;
561fe6060f1SDimitry Andric
5620b57cec5SDimitry Andric    typedef charT char_type;
5630b57cec5SDimitry Andric    typedef traits traits_type;
5640b57cec5SDimitry Andric    typedef basic_ostream<charT,traits> ostream_type;
5650b57cec5SDimitry Andric
5660b57cec5SDimitry Andric    ostream_iterator(ostream_type& s);
5670b57cec5SDimitry Andric    ostream_iterator(ostream_type& s, const charT* delimiter);
5680b57cec5SDimitry Andric    ostream_iterator(const ostream_iterator& x);
5690b57cec5SDimitry Andric    ~ostream_iterator();
5700b57cec5SDimitry Andric    ostream_iterator& operator=(const T& value);
5710b57cec5SDimitry Andric
5720b57cec5SDimitry Andric    ostream_iterator& operator*();
5730b57cec5SDimitry Andric    ostream_iterator& operator++();
5740b57cec5SDimitry Andric    ostream_iterator& operator++(int);
5750b57cec5SDimitry Andric};
5760b57cec5SDimitry Andric
5770b57cec5SDimitry Andrictemplate<class charT, class traits = char_traits<charT> >
5780b57cec5SDimitry Andricclass istreambuf_iterator
579fe6060f1SDimitry Andric    : public iterator<input_iterator_tag, charT, traits::off_type, unspecified, charT> // until C++17
5800b57cec5SDimitry Andric{
5810b57cec5SDimitry Andricpublic:
582fe6060f1SDimitry Andric    typedef input_iterator_tag              iterator_category;
583fe6060f1SDimitry Andric    typedef charT                           value_type;
584fe6060f1SDimitry Andric    typedef traits::off_type                difference_type;
585fe6060f1SDimitry Andric    typedef unspecified                     pointer;
586fe6060f1SDimitry Andric    typedef charT                           reference;
587fe6060f1SDimitry Andric
5880b57cec5SDimitry Andric    typedef charT                           char_type;
5890b57cec5SDimitry Andric    typedef traits                          traits_type;
590fe6060f1SDimitry Andric    typedef traits::int_type                int_type;
5910b57cec5SDimitry Andric    typedef basic_streambuf<charT, traits>  streambuf_type;
5920b57cec5SDimitry Andric    typedef basic_istream<charT, traits>    istream_type;
5930b57cec5SDimitry Andric
59481ad6265SDimitry Andric    istreambuf_iterator() noexcept; // constexpr since C++11
59581ad6265SDimitry Andric    constexpr istreambuf_iterator(default_sentinel_t) noexcept; // since C++20
5960b57cec5SDimitry Andric    istreambuf_iterator(istream_type& s) noexcept;
5970b57cec5SDimitry Andric    istreambuf_iterator(streambuf_type* s) noexcept;
5980b57cec5SDimitry Andric    istreambuf_iterator(a-private-type) noexcept;
5990b57cec5SDimitry Andric
6000b57cec5SDimitry Andric    charT                operator*() const;
6010b57cec5SDimitry Andric    pointer operator->() const;
6020b57cec5SDimitry Andric    istreambuf_iterator& operator++();
6030b57cec5SDimitry Andric    a-private-type       operator++(int);
6040b57cec5SDimitry Andric
6050b57cec5SDimitry Andric    bool equal(const istreambuf_iterator& b) const;
60681ad6265SDimitry Andric    friend bool operator==(const istreambuf_iterator& i, default_sentinel_t s); // since C++20
6070b57cec5SDimitry Andric};
6080b57cec5SDimitry Andric
6090b57cec5SDimitry Andrictemplate <class charT, class traits>
6100b57cec5SDimitry Andricbool operator==(const istreambuf_iterator<charT,traits>& a,
6110b57cec5SDimitry Andric                const istreambuf_iterator<charT,traits>& b);
6120b57cec5SDimitry Andrictemplate <class charT, class traits>
6130b57cec5SDimitry Andricbool operator!=(const istreambuf_iterator<charT,traits>& a,
61481ad6265SDimitry Andric                const istreambuf_iterator<charT,traits>& b); // until C++20
6150b57cec5SDimitry Andric
6160b57cec5SDimitry Andrictemplate <class charT, class traits = char_traits<charT> >
6170b57cec5SDimitry Andricclass ostreambuf_iterator
618fe6060f1SDimitry Andric    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
6190b57cec5SDimitry Andric{
6200b57cec5SDimitry Andricpublic:
621fe6060f1SDimitry Andric    typedef output_iterator_tag            iterator_category;
622fe6060f1SDimitry Andric    typedef void                           value_type;
623fe6060f1SDimitry Andric    typedef void                           difference_type; // until C++20
624fe6060f1SDimitry Andric    typedef ptrdiff_t                      difference_type; // since C++20
625fe6060f1SDimitry Andric    typedef void                           pointer;
626fe6060f1SDimitry Andric    typedef void                           reference;
627fe6060f1SDimitry Andric
6280b57cec5SDimitry Andric    typedef charT                          char_type;
6290b57cec5SDimitry Andric    typedef traits                         traits_type;
6300b57cec5SDimitry Andric    typedef basic_streambuf<charT, traits> streambuf_type;
6310b57cec5SDimitry Andric    typedef basic_ostream<charT, traits>   ostream_type;
6320b57cec5SDimitry Andric
6330b57cec5SDimitry Andric    ostreambuf_iterator(ostream_type& s) noexcept;
6340b57cec5SDimitry Andric    ostreambuf_iterator(streambuf_type* s) noexcept;
6350b57cec5SDimitry Andric    ostreambuf_iterator& operator=(charT c);
6360b57cec5SDimitry Andric    ostreambuf_iterator& operator*();
6370b57cec5SDimitry Andric    ostreambuf_iterator& operator++();
6380b57cec5SDimitry Andric    ostreambuf_iterator& operator++(int);
6390b57cec5SDimitry Andric    bool failed() const noexcept;
6400b57cec5SDimitry Andric};
6410b57cec5SDimitry Andric
6425f757f3fSDimitry Andrictemplate <class C> constexpr auto begin(C& c) -> decltype(c.begin());                   // constexpr since C++17
6435f757f3fSDimitry Andrictemplate <class C> constexpr auto begin(const C& c) -> decltype(c.begin());             // constexpr since C++17
6445f757f3fSDimitry Andrictemplate <class C> constexpr auto end(C& c) -> decltype(c.end());                       // constexpr since C++17
6455f757f3fSDimitry Andrictemplate <class C> constexpr auto end(const C& c) -> decltype(c.end());                 // constexpr since C++17
6465f757f3fSDimitry Andrictemplate <class T, size_t N> constexpr T* begin(T (&array)[N]) noexcept;
6475f757f3fSDimitry Andrictemplate <class T, size_t N> constexpr T* end(T (&array)[N]) noexcept;
6480b57cec5SDimitry Andric
6495f757f3fSDimitry Andrictemplate <class C> constexpr auto cbegin(const C& c) noexcept(see-below) -> decltype(std::begin(c)); // C++14
6505f757f3fSDimitry Andrictemplate <class C> constexpr auto cend(const C& c) noexcept(see-below) -> decltype(std::end(c));     // C++14
6515f757f3fSDimitry Andrictemplate <class C> constexpr auto rbegin(C& c) -> decltype(c.rbegin());                 // C++14, constexpr since C++17
6525f757f3fSDimitry Andrictemplate <class C> constexpr auto rbegin(const C& c) -> decltype(c.rbegin());           // C++14, constexpr since C++17
6535f757f3fSDimitry Andrictemplate <class C> constexpr auto rend(C& c) -> decltype(c.rend());                     // C++14, constexpr since C++17
6545f757f3fSDimitry Andrictemplate <class C> constexpr auto rend(const C& c) -> decltype(c.rend());               // C++14, constexpr since C++17
6555f757f3fSDimitry Andrictemplate <class E> constexpr reverse_iterator<const E*> rbegin(initializer_list<E> il); // C++14, constexpr since C++17
6565f757f3fSDimitry Andrictemplate <class E> constexpr reverse_iterator<const E*> rend(initializer_list<E> il);   // C++14, constexpr since C++17
6575f757f3fSDimitry Andrictemplate <class T, size_t N> constexpr reverse_iterator<T*> rbegin(T (&array)[N]);      // C++14, constexpr since C++17
6585f757f3fSDimitry Andrictemplate <class T, size_t N> constexpr reverse_iterator<T*> rend(T (&array)[N]);        // C++14, constexpr since C++17
6595f757f3fSDimitry Andrictemplate <class C> constexpr auto crbegin(const C& c) -> decltype(std::rbegin(c));      // C++14, constexpr since C++17
6605f757f3fSDimitry Andrictemplate <class C> constexpr auto crend(const C& c) -> decltype(std::rend(c));          // C++14, constexpr since C++17
6610b57cec5SDimitry Andric
6620b57cec5SDimitry Andric// 24.8, container access:
6630b57cec5SDimitry Andrictemplate <class C> constexpr auto size(const C& c) -> decltype(c.size());         // C++17
6640b57cec5SDimitry Andrictemplate <class T, size_t N> constexpr size_t size(const T (&array)[N]) noexcept; // C++17
6650b57cec5SDimitry Andric
6660b57cec5SDimitry Andrictemplate <class C> constexpr auto ssize(const C& c)
6670b57cec5SDimitry Andric    -> common_type_t<ptrdiff_t, make_signed_t<decltype(c.size())>>;                    // C++20
6680b57cec5SDimitry Andrictemplate <class T, ptrdiff_t> constexpr ptrdiff_t ssize(const T (&array)[N]) noexcept; // C++20
6690b57cec5SDimitry Andric
6700b57cec5SDimitry Andrictemplate <class C> constexpr auto empty(const C& c) -> decltype(c.empty());       // C++17
6710b57cec5SDimitry Andrictemplate <class T, size_t N> constexpr bool empty(const T (&array)[N]) noexcept;  // C++17
6720b57cec5SDimitry Andrictemplate <class E> constexpr bool empty(initializer_list<E> il) noexcept;         // C++17
6730b57cec5SDimitry Andrictemplate <class C> constexpr auto data(C& c) -> decltype(c.data());               // C++17
6740b57cec5SDimitry Andrictemplate <class C> constexpr auto data(const C& c) -> decltype(c.data());         // C++17
6750b57cec5SDimitry Andrictemplate <class T, size_t N> constexpr T* data(T (&array)[N]) noexcept;           // C++17
6760b57cec5SDimitry Andrictemplate <class E> constexpr const E* data(initializer_list<E> il) noexcept;      // C++17
6770b57cec5SDimitry Andric
6780b57cec5SDimitry Andric}  // std
6790b57cec5SDimitry Andric
6800b57cec5SDimitry Andric*/
6810b57cec5SDimitry Andric
6820b57cec5SDimitry Andric#include <__config>
683fe6060f1SDimitry Andric#include <__iterator/access.h>
684fe6060f1SDimitry Andric#include <__iterator/advance.h>
685fe6060f1SDimitry Andric#include <__iterator/back_insert_iterator.h>
686fe6060f1SDimitry Andric#include <__iterator/distance.h>
687fe6060f1SDimitry Andric#include <__iterator/front_insert_iterator.h>
688fe6060f1SDimitry Andric#include <__iterator/insert_iterator.h>
689fe6060f1SDimitry Andric#include <__iterator/istream_iterator.h>
69004eeddc0SDimitry Andric#include <__iterator/istreambuf_iterator.h>
69104eeddc0SDimitry Andric#include <__iterator/iterator.h>
69204eeddc0SDimitry Andric#include <__iterator/iterator_traits.h>
693fe6060f1SDimitry Andric#include <__iterator/move_iterator.h>
694fe6060f1SDimitry Andric#include <__iterator/next.h>
695fe6060f1SDimitry Andric#include <__iterator/ostream_iterator.h>
69604eeddc0SDimitry Andric#include <__iterator/ostreambuf_iterator.h>
697fe6060f1SDimitry Andric#include <__iterator/prev.h>
698*0fca6ea1SDimitry Andric#include <__iterator/reverse_iterator.h>
699*0fca6ea1SDimitry Andric#include <__iterator/wrap_iter.h>
700*0fca6ea1SDimitry Andric
701*0fca6ea1SDimitry Andric#if _LIBCPP_STD_VER >= 14
702*0fca6ea1SDimitry Andric#  include <__iterator/reverse_access.h>
703*0fca6ea1SDimitry Andric#endif
704*0fca6ea1SDimitry Andric
705*0fca6ea1SDimitry Andric#if _LIBCPP_STD_VER >= 17
706*0fca6ea1SDimitry Andric#  include <__iterator/data.h>
707*0fca6ea1SDimitry Andric#  include <__iterator/empty.h>
708*0fca6ea1SDimitry Andric#  include <__iterator/size.h>
709*0fca6ea1SDimitry Andric#endif
710*0fca6ea1SDimitry Andric
711*0fca6ea1SDimitry Andric#if _LIBCPP_STD_VER >= 20
712*0fca6ea1SDimitry Andric#  include <__iterator/common_iterator.h>
713*0fca6ea1SDimitry Andric#  include <__iterator/concepts.h>
714*0fca6ea1SDimitry Andric#  include <__iterator/counted_iterator.h>
715*0fca6ea1SDimitry Andric#  include <__iterator/default_sentinel.h>
716*0fca6ea1SDimitry Andric#  include <__iterator/incrementable_traits.h>
717*0fca6ea1SDimitry Andric#  include <__iterator/indirectly_comparable.h>
718*0fca6ea1SDimitry Andric#  include <__iterator/iter_move.h>
719*0fca6ea1SDimitry Andric#  include <__iterator/iter_swap.h>
720*0fca6ea1SDimitry Andric#  include <__iterator/mergeable.h>
721*0fca6ea1SDimitry Andric#  include <__iterator/move_sentinel.h>
722*0fca6ea1SDimitry Andric#  include <__iterator/permutable.h>
723fe6060f1SDimitry Andric#  include <__iterator/projected.h>
724fe6060f1SDimitry Andric#  include <__iterator/readable_traits.h>
72581ad6265SDimitry Andric#  include <__iterator/sortable.h>
726349cc55cSDimitry Andric#  include <__iterator/unreachable_sentinel.h>
727*0fca6ea1SDimitry Andric#endif
728*0fca6ea1SDimitry Andric
7290b57cec5SDimitry Andric#include <version>
7300b57cec5SDimitry Andric
731bdd1243dSDimitry Andric// standard-mandated includes
732bdd1243dSDimitry Andric
733bdd1243dSDimitry Andric// [iterator.synopsis]
734bdd1243dSDimitry Andric#include <compare>
735bdd1243dSDimitry Andric#include <concepts>
73681ad6265SDimitry Andric
7370b57cec5SDimitry Andric#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
7380b57cec5SDimitry Andric#  pragma GCC system_header
7390b57cec5SDimitry Andric#endif
7400b57cec5SDimitry Andric
741*0fca6ea1SDimitry Andric#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 17
742*0fca6ea1SDimitry Andric#  include <variant>
743*0fca6ea1SDimitry Andric#endif
744*0fca6ea1SDimitry Andric
745bdd1243dSDimitry Andric#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
74606c3fb27SDimitry Andric#  include <cstdlib>
747bdd1243dSDimitry Andric#  include <exception>
748bdd1243dSDimitry Andric#  include <new>
749bdd1243dSDimitry Andric#  include <type_traits>
750bdd1243dSDimitry Andric#  include <typeinfo>
751bdd1243dSDimitry Andric#  include <utility>
752bdd1243dSDimitry Andric#endif
753bdd1243dSDimitry Andric
7540b57cec5SDimitry Andric#endif // _LIBCPP_ITERATOR
755