xref: /freebsd/contrib/llvm-project/libcxx/include/iterator (revision 06c3fb2749bda94cb5201f81ffdb8fa6c3161b2e)
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
11#define _LIBCPP_ITERATOR
12
13/*
14    iterator synopsis
15
16#include <concepts>
17
18namespace std
19{
20template<class> struct incrementable_traits;       // since C++20
21template<class T>
22  using iter_difference_t = see below;             // since C++20
23
24template<class> struct indirectly_readable_traits; // since C++20
25template<class T>
26  using iter_value_t = see below;                  // since C++20
27
28template<class Iterator>
29struct iterator_traits;
30
31template<class T>
32  requires is_object_v<T>                    // since C++20
33struct iterator_traits<T*>;
34
35template<dereferenceable T>
36  using iter_reference_t = decltype(*declval<T&>());
37
38namespace ranges::inline unspecified {
39    inline constexpr unspecified iter_move = unspecified; // since C++20, nodiscard as an extension
40}}
41
42template<dereferenceable T>
43  requires ...
44using iter_rvalue_reference_t = decltype(ranges::iter_move(declval<T&>())); // since C++20
45
46// [iterator.concepts], iterator concepts
47// [iterator.concept.readable], concept indirectly_readable
48template<class In>
49  concept indirectly_readable = see below;                      // since C++20
50
51template<indirectly_readable T>
52  using iter_common_reference_t =
53    common_reference_t<iter_reference_t<T>, iter_value_t<T>&>;  // since C++20
54
55// [iterator.concept.writable], concept indirectly_writable
56template<class Out, class T>
57  concept indirectly_writable = see below;                // since C++20
58
59// [iterator.concept.winc], concept weakly_incrementable
60template<class I>
61  concept weakly_incrementable = see below;                // since C++20
62
63// [iterator.concept.inc], concept incrementable
64template<class I>
65  concept incrementable = see below;                       // since C++20
66
67// [iterator.concept.iterator], concept input_or_output_iterator
68  template<class I>
69    concept input_or_output_iterator = see below;          // since C++20
70
71// [iterator.concept.sentinel], concept sentinel_for
72template<class S, class I>
73  concept sentinel_for = see below;                        // since C++20
74
75// [iterator.concept.sizedsentinel], concept sized_sentinel_for
76template<class S, class I>
77  inline constexpr bool disable_sized_sentinel_for = false;
78
79template<class S, class I>
80  concept sized_sentinel_for = see below;
81
82// [iterator.concept.input], concept input_iterator
83template<class I>
84  concept input_iterator = see below;                      // since C++20
85
86// [iterator.concept.output], concept output_iterator
87template<class I, class T>
88  concept output_iterator = see below;                     // since C++20
89
90// [iterator.concept.forward], concept forward_iterator
91template<class I>
92  concept forward_iterator = see below;                    // since C++20
93
94// [iterator.concept.bidir], concept bidirectional_iterator
95template<class I>
96  concept bidirectional_iterator = see below;              // since C++20
97
98// [iterator.concept.random.access], concept random_access_iterator
99template<class I>
100  concept random_access_iterator = see below;              // since C++20
101
102// [indirectcallable]
103// [indirectcallable.indirectinvocable]
104template<class F, class I>
105  concept indirectly_unary_invocable = see below;          // since C++20
106
107template<class F, class I>
108  concept indirectly_regular_unary_invocable = see below;  // since C++20
109
110template<class F, class I>
111  concept indirect_unary_predicate = see below;            // since C++20
112
113template<class F, class I1, class I2>
114  concept indirect_binary_predicate = see below;           // since C++20
115
116template<class F, class I1, class I2 = I1>
117  concept indirect_equivalence_relation = see below;       // since C++20
118
119template<class F, class I1, class I2 = I1>
120  concept indirect_strict_weak_order = see below;          // since C++20
121
122template<class F, class... Is>
123  using indirect_result_t = see below;                     // since C++20
124
125// [projected], projected
126template<indirectly_readable I, indirectly_regular_unary_invocable<I> Proj>
127  struct projected;                                        // since C++20
128
129template<weakly_incrementable I, indirectly_regular_unary_invocable<I> Proj>
130  struct incrementable_traits<projected<I, Proj>>;         // since C++20
131
132// [alg.req.ind.move], concept indirectly_movable
133template<class In, class Out>
134  concept indirectly_movable = see below;                  // since C++20
135
136template<class In, class Out>
137  concept indirectly_movable_storable = see below;         // since C++20
138
139// [alg.req.ind.copy], concept indirectly_copyable
140template<class In, class Out>
141  concept indirectly_copyable = see below;                 // since C++20
142
143template<class In, class Out>
144  concept indirectly_copyable_storable = see below;        // since C++20
145
146// [alg.req.ind.swap], concept indirectly_swappable
147template<class I1, class I2 = I1>
148  concept indirectly_swappable = see below;                // since C++20
149
150template<class I1, class I2, class R, class P1 = identity,
151         class P2 = identity>
152  concept indirectly_comparable =
153    indirect_binary_predicate<R, projected<I1, P1>, projected<I2, P2>>; // since C++20
154
155// [alg.req.permutable], concept permutable
156template<class I>
157  concept permutable = see below;                          // since C++20
158
159 // [alg.req.mergeable], concept mergeable
160template<class I1, class I2, class Out,
161    class R = ranges::less, class P1 = identity, class P2 = identity>
162  concept mergeable = see below;                           // since C++20
163
164// [alg.req.sortable], concept sortable
165template<class I, class R = ranges::less, class P = identity>
166  concept sortable = see below;                            // since C++20
167
168template<input_or_output_iterator I, sentinel_for<I> S>
169  requires (!same_as<I, S> && copyable<I>)
170class common_iterator;                                     // since C++20
171
172template<class Category, class T, class Distance = ptrdiff_t,
173         class Pointer = T*, class Reference = T&>
174struct iterator                                            // deprecated in C++17
175{
176    typedef T         value_type;
177    typedef Distance  difference_type;
178    typedef Pointer   pointer;
179    typedef Reference reference;
180    typedef Category  iterator_category;
181};
182
183struct input_iterator_tag  {};
184struct output_iterator_tag {};
185struct forward_iterator_tag       : public input_iterator_tag         {};
186struct bidirectional_iterator_tag : public forward_iterator_tag       {};
187struct random_access_iterator_tag : public bidirectional_iterator_tag {};
188struct contiguous_iterator_tag    : public random_access_iterator_tag {};
189
190// 27.4.3, iterator operations
191template <class InputIterator, class Distance>  // constexpr in C++17
192  constexpr void advance(InputIterator& i, Distance n);
193
194template <class InputIterator>  // constexpr in C++17
195  constexpr typename iterator_traits<InputIterator>::difference_type
196    distance(InputIterator first, InputIterator last);
197
198template <class InputIterator>  // constexpr in C++17
199  constexpr InputIterator next(InputIterator x,
200typename iterator_traits<InputIterator>::difference_type n = 1);
201
202template <class BidirectionalIterator>  // constexpr in C++17
203  constexpr BidirectionalIterator prev(BidirectionalIterator x,
204    typename iterator_traits<BidirectionalIterator>::difference_type n = 1);
205
206// [range.iter.ops], range iterator operations
207namespace ranges {
208  // [range.iter.op.advance], ranges::advance
209  template<input_or_output_iterator I>
210    constexpr void advance(I& i, iter_difference_t<I> n);                          // since C++20
211  template<input_or_output_iterator I, sentinel_for<I> S>
212    constexpr void advance(I& i, S bound);                                         // since C++20
213  template<input_or_output_iterator I, sentinel_for<I> S>
214    constexpr iter_difference_t<I> advance(I& i, iter_difference_t<I> n, S bound); // since C++20
215}
216
217template <class Iterator>
218class reverse_iterator
219    : public iterator<typename iterator_traits<Iterator>::iterator_category, // until C++17
220                      typename iterator_traits<Iterator>::value_type,
221                      typename iterator_traits<Iterator>::difference_type,
222                      typename iterator_traits<Iterator>::pointer,
223                      typename iterator_traits<Iterator>::reference>
224{
225protected:
226    Iterator current;
227public:
228    using iterator_type     = Iterator;
229    using iterator_concept  = see below; // since C++20
230    using iterator_category = typename iterator_traits<Iterator>::iterator_category; // since C++17, until C++20
231    using iterator_category = see below; // since C++20
232    using value_type        = typename iterator_traits<Iterator>::value_type; // since C++17, until C++20
233    using value_type        = iter_value_t<Iterator>; // since C++20
234    using difference_type   = typename iterator_traits<Iterator>::difference_type; // until C++20
235    using difference_type   = iter_difference_t<Iterator>; // since C++20
236    using pointer           = typename iterator_traits<Iterator>::pointer;
237    using reference         = typename iterator_traits<Iterator>::reference; // until C++20
238    using reference         = iter_reference_t<Iterator>; // since C++20
239
240    constexpr reverse_iterator();
241    constexpr explicit reverse_iterator(Iterator x);
242    template <class U> constexpr reverse_iterator(const reverse_iterator<U>& u);
243    template <class U> constexpr reverse_iterator& operator=(const reverse_iterator<U>& u);
244    constexpr Iterator base() const;
245    constexpr reference operator*() const;
246    constexpr pointer   operator->() const; // until C++20
247    constexpr pointer   operator->() const requires see below; // since C++20
248    constexpr reverse_iterator& operator++();
249    constexpr reverse_iterator  operator++(int);
250    constexpr reverse_iterator& operator--();
251    constexpr reverse_iterator  operator--(int);
252    constexpr reverse_iterator  operator+ (difference_type n) const;
253    constexpr reverse_iterator& operator+=(difference_type n);
254    constexpr reverse_iterator  operator- (difference_type n) const;
255    constexpr reverse_iterator& operator-=(difference_type n);
256    constexpr unspecified       operator[](difference_type n) const;
257
258    friend constexpr iter_rvalue_reference_t<Iterator>
259      iter_move(const reverse_iterator& i) noexcept(see below);
260    template<indirectly_swappable<Iterator> Iterator2>
261      friend constexpr void
262        iter_swap(const reverse_iterator& x,
263                  const reverse_iterator<Iterator2>& y) noexcept(see below);
264};
265
266template <class Iterator1, class Iterator2>
267constexpr bool                          // constexpr in C++17
268operator==(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
269
270template <class Iterator1, class Iterator2>
271constexpr bool                          // constexpr in C++17
272operator!=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
273
274template <class Iterator1, class Iterator2>
275constexpr bool                          // constexpr in C++17
276operator<(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
277
278template <class Iterator1, class Iterator2>
279constexpr bool                          // constexpr in C++17
280operator>(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
281
282template <class Iterator1, class Iterator2>
283constexpr bool                          // constexpr in C++17
284operator<=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
285
286template <class Iterator1, class Iterator2>
287constexpr bool                          // constexpr in C++17
288operator>=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
289
290template<class Iterator1, three_way_comparable_with<Iterator1> Iterator2>
291  constexpr compare_three_way_result_t<Iterator1, Iterator2>
292    operator<=>(const reverse_iterator<Iterator1>& x,
293                const reverse_iterator<Iterator2>& y);
294
295template <class Iterator1, class Iterator2>
296constexpr auto
297operator-(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y)
298-> decltype(__y.base() - __x.base());   // constexpr in C++17
299
300template <class Iterator>
301constexpr reverse_iterator<Iterator>
302operator+(typename reverse_iterator<Iterator>::difference_type n,
303          const reverse_iterator<Iterator>& x);   // constexpr in C++17
304
305template <class Iterator>
306constexpr reverse_iterator<Iterator> make_reverse_iterator(Iterator i); // C++14, constexpr in C++17
307
308template<class Iterator1, class Iterator2>
309    requires (!sized_sentinel_for<Iterator1, Iterator2>)
310  inline constexpr bool disable_sized_sentinel_for<reverse_iterator<Iterator1>,
311                                                   reverse_iterator<Iterator2>> = true;
312
313template <class Container>
314class back_insert_iterator
315    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
316{
317protected:
318    Container* container;
319public:
320    typedef Container                   container_type;
321    typedef void                        value_type;
322    typedef void                        difference_type; // until C++20
323    typedef ptrdiff_t                   difference_type; // since C++20
324    typedef void                        reference;
325    typedef void                        pointer;
326
327    explicit back_insert_iterator(Container& x);  // constexpr in C++20
328    back_insert_iterator& operator=(const typename Container::value_type& value);  // constexpr in C++20
329    back_insert_iterator& operator*();  // constexpr in C++20
330    back_insert_iterator& operator++();  // constexpr in C++20
331    back_insert_iterator  operator++(int);  // constexpr in C++20
332};
333
334template <class Container> back_insert_iterator<Container> back_inserter(Container& x);  // constexpr in C++20
335
336template <class Container>
337class front_insert_iterator
338    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
339{
340protected:
341    Container* container;
342public:
343    typedef Container                    container_type;
344    typedef void                         value_type;
345    typedef void                         difference_type; // until C++20
346    typedef ptrdiff_t                    difference_type; // since C++20
347    typedef void                         reference;
348    typedef void                         pointer;
349
350    explicit front_insert_iterator(Container& x);  // constexpr in C++20
351    front_insert_iterator& operator=(const typename Container::value_type& value);  // constexpr in C++20
352    front_insert_iterator& operator*();  // constexpr in C++20
353    front_insert_iterator& operator++();  // constexpr in C++20
354    front_insert_iterator  operator++(int);  // constexpr in C++20
355};
356
357template <class Container> front_insert_iterator<Container> front_inserter(Container& x);  // constexpr in C++20
358
359template <class Container>
360class insert_iterator
361    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
362{
363protected:
364    Container* container;
365    typename Container::iterator iter;
366public:
367    typedef Container              container_type;
368    typedef void                   value_type;
369    typedef void                   difference_type; // until C++20
370    typedef ptrdiff_t              difference_type; // since C++20
371    typedef void                   reference;
372    typedef void                   pointer;
373
374    insert_iterator(Container& x, typename Container::iterator i);  // constexpr in C++20
375    insert_iterator& operator=(const typename Container::value_type& value);  // constexpr in C++20
376    insert_iterator& operator*();  // constexpr in C++20
377    insert_iterator& operator++();  // constexpr in C++20
378    insert_iterator& operator++(int);  // constexpr in C++20
379};
380
381template <class Container>
382insert_iterator<Container> inserter(Container& x, typename Container::iterator i);  // until C++20
383template <class Container>
384constexpr insert_iterator<Container> inserter(Container& x, ranges::iterator_t<Container> i);  // since C++20
385
386template <class Iterator>
387class move_iterator {
388public:
389    using iterator_type     = Iterator;
390    using iterator_concept  = see below; // From C++20
391    using iterator_category = see below; // not always present starting from C++20
392    using value_type        = iter_value_t<Iterator>; // Until C++20, iterator_traits<Iterator>::value_type
393    using difference_type   = iter_difference_t<Iterator>; // Until C++20, iterator_traits<Iterator>::difference_type;
394    using pointer           = Iterator;
395    using reference         = iter_rvalue_reference_t<Iterator>; // Until C++20, value_type&&
396
397    constexpr move_iterator();  // all the constexprs are in C++17
398    constexpr explicit move_iterator(Iterator i);
399    template <class U>
400      constexpr move_iterator(const move_iterator<U>& u);
401    template <class U>
402      constexpr move_iterator& operator=(const move_iterator<U>& u);
403
404    constexpr iterator_type base() const; // Until C++20
405    constexpr const Iterator& base() const & noexcept; // From C++20
406    constexpr Iterator base() &&; // From C++20
407
408    constexpr reference operator*() const;
409    constexpr pointer operator->() const; // Deprecated in C++20
410    constexpr move_iterator& operator++();
411    constexpr auto operator++(int); // Return type was move_iterator until C++20
412    constexpr move_iterator& operator--();
413    constexpr move_iterator operator--(int);
414    constexpr move_iterator operator+(difference_type n) const;
415    constexpr move_iterator& operator+=(difference_type n);
416    constexpr move_iterator operator-(difference_type n) const;
417    constexpr move_iterator& operator-=(difference_type n);
418    constexpr reference operator[](difference_type n) const; // Return type unspecified until C++20
419
420    template<sentinel_for<Iterator> S>
421      friend constexpr bool
422        operator==(const move_iterator& x, const move_sentinel<S>& y); // Since C++20
423    template<sized_sentinel_for<Iterator> S>
424      friend constexpr iter_difference_t<Iterator>
425        operator-(const move_sentinel<S>& x, const move_iterator& y); // Since C++20
426    template<sized_sentinel_for<Iterator> S>
427      friend constexpr iter_difference_t<Iterator>
428        operator-(const move_iterator& x, const move_sentinel<S>& y); // Since C++20
429    friend constexpr iter_rvalue_reference_t<Iterator>
430      iter_move(const move_iterator& i)
431        noexcept(noexcept(ranges::iter_move(i.current))); // Since C++20
432    template<indirectly_swappable<Iterator> Iterator2>
433      friend constexpr void
434        iter_swap(const move_iterator& x, const move_iterator<Iterator2>& y)
435          noexcept(noexcept(ranges::iter_swap(x.current, y.current))); // Since C++20
436
437private:
438    Iterator current; // exposition only
439};
440
441template <class Iterator1, class Iterator2>
442constexpr bool   // constexpr in C++17
443operator==(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
444
445template <class Iterator1, class Iterator2>
446constexpr bool   // constexpr in C++17
447operator!=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
448
449template <class Iterator1, class Iterator2>
450constexpr bool   // constexpr in C++17
451operator<(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
452
453template <class Iterator1, class Iterator2>
454constexpr bool   // constexpr in C++17
455operator<=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
456
457template <class Iterator1, class Iterator2>
458constexpr bool   // constexpr in C++17
459operator>(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
460
461template <class Iterator1, class Iterator2>
462constexpr bool   // constexpr in C++17
463operator>=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
464
465template <class Iterator1, class Iterator2>
466constexpr auto   // constexpr in C++17
467operator-(const move_iterator<Iterator1>& x,
468          const move_iterator<Iterator2>& y) -> decltype(x.base() - y.base());
469
470template <class Iterator>
471constexpr move_iterator<Iterator> operator+(   // constexpr in C++17
472            typename move_iterator<Iterator>::difference_type n,
473            const move_iterator<Iterator>& x);
474
475template <class Iterator>   // constexpr in C++17
476constexpr  move_iterator<Iterator> make_move_iterator(const Iterator& i);
477
478template<semiregular S>
479class move_sentinel {
480public:
481  constexpr move_sentinel();
482  constexpr explicit move_sentinel(S s);
483  template<class S2>
484    requires convertible_to<const S2&, S>
485      constexpr move_sentinel(const move_sentinel<S2>& s);
486  template<class S2>
487    requires assignable_from<S&, const S2&>
488      constexpr move_sentinel& operator=(const move_sentinel<S2>& s);
489
490  constexpr S base() const;
491private:
492  S last;     // exposition only
493};
494
495// [default.sentinel], default sentinel
496struct default_sentinel_t;
497inline constexpr default_sentinel_t default_sentinel{};
498
499// [iterators.counted], counted iterators
500template<input_or_output_iterator I> class counted_iterator;
501
502template<input_iterator I>
503  requires see below
504  struct iterator_traits<counted_iterator<I>>;
505
506// [unreachable.sentinel], unreachable sentinel
507struct unreachable_sentinel_t;
508inline constexpr unreachable_sentinel_t unreachable_sentinel{};
509
510template <class T, class charT = char, class traits = char_traits<charT>, class Distance = ptrdiff_t>
511class istream_iterator
512    : public iterator<input_iterator_tag, T, Distance, const T*, const T&> // until C++17
513{
514public:
515    typedef input_iterator_tag           iterator_category;
516    typedef T                            value_type;
517    typedef Distance                     difference_type;
518    typedef const T*                     pointer;
519    typedef const T&                     reference;
520
521    typedef charT                        char_type;
522    typedef traits                       traits_type;
523    typedef basic_istream<charT, traits> istream_type;
524
525    istream_iterator(); // constexpr since C++11
526    constexpr istream_iterator(default_sentinel_t); // since C++20
527    istream_iterator(istream_type& s);
528    istream_iterator(const istream_iterator& x);
529    ~istream_iterator();
530
531    const T& operator*() const;
532    const T* operator->() const;
533    istream_iterator& operator++();
534    istream_iterator  operator++(int);
535    friend bool operator==(const istream_iterator& i, default_sentinel_t); // since C++20
536};
537
538template <class T, class charT, class traits, class Distance>
539bool operator==(const istream_iterator<T,charT,traits,Distance>& x,
540                const istream_iterator<T,charT,traits,Distance>& y);
541template <class T, class charT, class traits, class Distance>
542bool operator!=(const istream_iterator<T,charT,traits,Distance>& x,
543                const istream_iterator<T,charT,traits,Distance>& y); // until C++20
544
545template <class T, class charT = char, class traits = char_traits<charT> >
546class ostream_iterator
547    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
548{
549public:
550    typedef output_iterator_tag         iterator_category;
551    typedef void                        value_type;
552    typedef void                        difference_type; // until C++20
553    typedef ptrdiff_t                   difference_type; // since C++20
554    typedef void                        pointer;
555    typedef void                        reference;
556
557    typedef charT char_type;
558    typedef traits traits_type;
559    typedef basic_ostream<charT,traits> ostream_type;
560
561    ostream_iterator(ostream_type& s);
562    ostream_iterator(ostream_type& s, const charT* delimiter);
563    ostream_iterator(const ostream_iterator& x);
564    ~ostream_iterator();
565    ostream_iterator& operator=(const T& value);
566
567    ostream_iterator& operator*();
568    ostream_iterator& operator++();
569    ostream_iterator& operator++(int);
570};
571
572template<class charT, class traits = char_traits<charT> >
573class istreambuf_iterator
574    : public iterator<input_iterator_tag, charT, traits::off_type, unspecified, charT> // until C++17
575{
576public:
577    typedef input_iterator_tag              iterator_category;
578    typedef charT                           value_type;
579    typedef traits::off_type                difference_type;
580    typedef unspecified                     pointer;
581    typedef charT                           reference;
582
583    typedef charT                           char_type;
584    typedef traits                          traits_type;
585    typedef traits::int_type                int_type;
586    typedef basic_streambuf<charT, traits>  streambuf_type;
587    typedef basic_istream<charT, traits>    istream_type;
588
589    istreambuf_iterator() noexcept; // constexpr since C++11
590    constexpr istreambuf_iterator(default_sentinel_t) noexcept; // since C++20
591    istreambuf_iterator(istream_type& s) noexcept;
592    istreambuf_iterator(streambuf_type* s) noexcept;
593    istreambuf_iterator(a-private-type) noexcept;
594
595    charT                operator*() const;
596    pointer operator->() const;
597    istreambuf_iterator& operator++();
598    a-private-type       operator++(int);
599
600    bool equal(const istreambuf_iterator& b) const;
601    friend bool operator==(const istreambuf_iterator& i, default_sentinel_t s); // since C++20
602};
603
604template <class charT, class traits>
605bool operator==(const istreambuf_iterator<charT,traits>& a,
606                const istreambuf_iterator<charT,traits>& b);
607template <class charT, class traits>
608bool operator!=(const istreambuf_iterator<charT,traits>& a,
609                const istreambuf_iterator<charT,traits>& b); // until C++20
610
611template <class charT, class traits = char_traits<charT> >
612class ostreambuf_iterator
613    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
614{
615public:
616    typedef output_iterator_tag            iterator_category;
617    typedef void                           value_type;
618    typedef void                           difference_type; // until C++20
619    typedef ptrdiff_t                      difference_type; // since C++20
620    typedef void                           pointer;
621    typedef void                           reference;
622
623    typedef charT                          char_type;
624    typedef traits                         traits_type;
625    typedef basic_streambuf<charT, traits> streambuf_type;
626    typedef basic_ostream<charT, traits>   ostream_type;
627
628    ostreambuf_iterator(ostream_type& s) noexcept;
629    ostreambuf_iterator(streambuf_type* s) noexcept;
630    ostreambuf_iterator& operator=(charT c);
631    ostreambuf_iterator& operator*();
632    ostreambuf_iterator& operator++();
633    ostreambuf_iterator& operator++(int);
634    bool failed() const noexcept;
635};
636
637template <class C> constexpr auto begin(C& c) -> decltype(c.begin());
638template <class C> constexpr auto begin(const C& c) -> decltype(c.begin());
639template <class C> constexpr auto end(C& c) -> decltype(c.end());
640template <class C> constexpr auto end(const C& c) -> decltype(c.end());
641template <class T, size_t N> constexpr T* begin(T (&array)[N]);
642template <class T, size_t N> constexpr T* end(T (&array)[N]);
643
644template <class C> auto constexpr cbegin(const C& c) -> decltype(std::begin(c));        // C++14
645template <class C> auto constexpr cend(const C& c) -> decltype(std::end(c));            // C++14
646template <class C> auto constexpr rbegin(C& c) -> decltype(c.rbegin());                 // C++14
647template <class C> auto constexpr rbegin(const C& c) -> decltype(c.rbegin());           // C++14
648template <class C> auto constexpr rend(C& c) -> decltype(c.rend());                     // C++14
649template <class C> constexpr auto rend(const C& c) -> decltype(c.rend());               // C++14
650template <class E> reverse_iterator<const E*> constexpr rbegin(initializer_list<E> il); // C++14
651template <class E> reverse_iterator<const E*> constexpr rend(initializer_list<E> il);   // C++14
652template <class T, size_t N> reverse_iterator<T*> constexpr rbegin(T (&array)[N]);      // C++14
653template <class T, size_t N> reverse_iterator<T*> constexpr rend(T (&array)[N]);        // C++14
654template <class C> constexpr auto crbegin(const C& c) -> decltype(std::rbegin(c));      // C++14
655template <class C> constexpr auto crend(const C& c) -> decltype(std::rend(c));          // C++14
656
657// 24.8, container access:
658template <class C> constexpr auto size(const C& c) -> decltype(c.size());         // C++17
659template <class T, size_t N> constexpr size_t size(const T (&array)[N]) noexcept; // C++17
660
661template <class C> constexpr auto ssize(const C& c)
662    -> common_type_t<ptrdiff_t, make_signed_t<decltype(c.size())>>;                    // C++20
663template <class T, ptrdiff_t> constexpr ptrdiff_t ssize(const T (&array)[N]) noexcept; // C++20
664
665template <class C> constexpr auto empty(const C& c) -> decltype(c.empty());       // C++17
666template <class T, size_t N> constexpr bool empty(const T (&array)[N]) noexcept;  // C++17
667template <class E> constexpr bool empty(initializer_list<E> il) noexcept;         // C++17
668template <class C> constexpr auto data(C& c) -> decltype(c.data());               // C++17
669template <class C> constexpr auto data(const C& c) -> decltype(c.data());         // C++17
670template <class T, size_t N> constexpr T* data(T (&array)[N]) noexcept;           // C++17
671template <class E> constexpr const E* data(initializer_list<E> il) noexcept;      // C++17
672
673}  // std
674
675*/
676
677#include <__assert> // all public C++ headers provide the assertion handler
678#include <__config>
679#include <__iterator/access.h>
680#include <__iterator/advance.h>
681#include <__iterator/back_insert_iterator.h>
682#include <__iterator/bounded_iter.h>
683#include <__iterator/common_iterator.h>
684#include <__iterator/concepts.h>
685#include <__iterator/counted_iterator.h>
686#include <__iterator/data.h>
687#include <__iterator/default_sentinel.h>
688#include <__iterator/distance.h>
689#include <__iterator/empty.h>
690#include <__iterator/erase_if_container.h>
691#include <__iterator/front_insert_iterator.h>
692#include <__iterator/incrementable_traits.h>
693#include <__iterator/indirectly_comparable.h>
694#include <__iterator/insert_iterator.h>
695#include <__iterator/istream_iterator.h>
696#include <__iterator/istreambuf_iterator.h>
697#include <__iterator/iter_move.h>
698#include <__iterator/iter_swap.h>
699#include <__iterator/iterator.h>
700#include <__iterator/iterator_traits.h>
701#include <__iterator/mergeable.h>
702#include <__iterator/move_iterator.h>
703#include <__iterator/move_sentinel.h>
704#include <__iterator/next.h>
705#include <__iterator/ostream_iterator.h>
706#include <__iterator/ostreambuf_iterator.h>
707#include <__iterator/permutable.h>
708#include <__iterator/prev.h>
709#include <__iterator/projected.h>
710#include <__iterator/readable_traits.h>
711#include <__iterator/reverse_access.h>
712#include <__iterator/reverse_iterator.h>
713#include <__iterator/size.h>
714#include <__iterator/sortable.h>
715#include <__iterator/unreachable_sentinel.h>
716#include <__iterator/wrap_iter.h>
717#include <__memory/addressof.h>
718#include <__memory/pointer_traits.h>
719#include <cstddef>
720#include <initializer_list>
721#include <version>
722
723// standard-mandated includes
724
725// [iterator.synopsis]
726#include <compare>
727#include <concepts>
728
729#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
730#  pragma GCC system_header
731#endif
732
733#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
734#  include <cstdlib>
735#  include <exception>
736#  include <new>
737#  include <type_traits>
738#  include <typeinfo>
739#  include <utility>
740#endif
741
742#endif // _LIBCPP_ITERATOR
743