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                // since C++20
156template<class I>
157  concept permutable = see below;
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
164template<input_or_output_iterator I, sentinel_for<I> S>
165  requires (!same_as<I, S> && copyable<I>)
166class common_iterator;                                     // since C++20
167
168template<class Category, class T, class Distance = ptrdiff_t,
169         class Pointer = T*, class Reference = T&>
170struct iterator                                            // deprecated in C++17
171{
172    typedef T         value_type;
173    typedef Distance  difference_type;
174    typedef Pointer   pointer;
175    typedef Reference reference;
176    typedef Category  iterator_category;
177};
178
179struct input_iterator_tag  {};
180struct output_iterator_tag {};
181struct forward_iterator_tag       : public input_iterator_tag         {};
182struct bidirectional_iterator_tag : public forward_iterator_tag       {};
183struct random_access_iterator_tag : public bidirectional_iterator_tag {};
184struct contiguous_iterator_tag    : public random_access_iterator_tag {};
185
186// 27.4.3, iterator operations
187template <class InputIterator, class Distance>  // constexpr in C++17
188  constexpr void advance(InputIterator& i, Distance n);
189
190template <class InputIterator>  // constexpr in C++17
191  constexpr typename iterator_traits<InputIterator>::difference_type
192    distance(InputIterator first, InputIterator last);
193
194template <class InputIterator>  // constexpr in C++17
195  constexpr InputIterator next(InputIterator x,
196typename iterator_traits<InputIterator>::difference_type n = 1);
197
198template <class BidirectionalIterator>  // constexpr in C++17
199  constexpr BidirectionalIterator prev(BidirectionalIterator x,
200    typename iterator_traits<BidirectionalIterator>::difference_type n = 1);
201
202// [range.iter.ops], range iterator operations
203namespace ranges {
204  // [range.iter.op.advance], ranges::advance
205  template<input_or_output_iterator I>
206    constexpr void advance(I& i, iter_difference_t<I> n);                          // since C++20
207  template<input_or_output_iterator I, sentinel_for<I> S>
208    constexpr void advance(I& i, S bound);                                         // since C++20
209  template<input_or_output_iterator I, sentinel_for<I> S>
210    constexpr iter_difference_t<I> advance(I& i, iter_difference_t<I> n, S bound); // since C++20
211}
212
213template <class Iterator>
214class reverse_iterator
215    : public iterator<typename iterator_traits<Iterator>::iterator_category, // until C++17
216                      typename iterator_traits<Iterator>::value_type,
217                      typename iterator_traits<Iterator>::difference_type,
218                      typename iterator_traits<Iterator>::pointer,
219                      typename iterator_traits<Iterator>::reference>
220{
221protected:
222    Iterator current;
223public:
224    typedef Iterator                                            iterator_type;
225    typedef typename iterator_traits<Iterator>::difference_type difference_type;
226    typedef typename iterator_traits<Iterator>::reference       reference;
227    typedef typename iterator_traits<Iterator>::pointer         pointer;
228
229    constexpr reverse_iterator();
230    constexpr explicit reverse_iterator(Iterator x);
231    template <class U> constexpr reverse_iterator(const reverse_iterator<U>& u);
232    template <class U> constexpr reverse_iterator& operator=(const reverse_iterator<U>& u);
233    constexpr Iterator base() const;
234    constexpr reference operator*() const;
235    constexpr pointer   operator->() const;
236    constexpr reverse_iterator& operator++();
237    constexpr reverse_iterator  operator++(int);
238    constexpr reverse_iterator& operator--();
239    constexpr reverse_iterator  operator--(int);
240    constexpr reverse_iterator  operator+ (difference_type n) const;
241    constexpr reverse_iterator& operator+=(difference_type n);
242    constexpr reverse_iterator  operator- (difference_type n) const;
243    constexpr reverse_iterator& operator-=(difference_type n);
244    constexpr reference         operator[](difference_type n) const;
245};
246
247template <class Iterator1, class Iterator2>
248constexpr bool                          // constexpr in C++17
249operator==(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
250
251template <class Iterator1, class Iterator2>
252constexpr bool                          // constexpr in C++17
253operator<(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
254
255template <class Iterator1, class Iterator2>
256constexpr bool                          // constexpr in C++17
257operator!=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
258
259template <class Iterator1, class Iterator2>
260constexpr bool                          // constexpr in C++17
261operator>(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
262
263template <class Iterator1, class Iterator2>
264constexpr bool                          // constexpr in C++17
265operator>=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
266
267template <class Iterator1, class Iterator2>
268constexpr bool                          // constexpr in C++17
269operator<=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
270
271template <class Iterator1, class Iterator2>
272constexpr auto
273operator-(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y)
274-> decltype(__y.base() - __x.base());   // constexpr in C++17
275
276template <class Iterator>
277constexpr reverse_iterator<Iterator>
278operator+(typename reverse_iterator<Iterator>::difference_type n,
279          const reverse_iterator<Iterator>& x);   // constexpr in C++17
280
281template <class Iterator>
282constexpr reverse_iterator<Iterator> make_reverse_iterator(Iterator i); // C++14, constexpr in C++17
283
284template <class Container>
285class back_insert_iterator
286    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
287{
288protected:
289    Container* container;
290public:
291    typedef Container                   container_type;
292    typedef void                        value_type;
293    typedef void                        difference_type; // until C++20
294    typedef ptrdiff_t                   difference_type; // since C++20
295    typedef void                        reference;
296    typedef void                        pointer;
297
298    explicit back_insert_iterator(Container& x);  // constexpr in C++20
299    back_insert_iterator& operator=(const typename Container::value_type& value);  // constexpr in C++20
300    back_insert_iterator& operator*();  // constexpr in C++20
301    back_insert_iterator& operator++();  // constexpr in C++20
302    back_insert_iterator  operator++(int);  // constexpr in C++20
303};
304
305template <class Container> back_insert_iterator<Container> back_inserter(Container& x);  // constexpr in C++20
306
307template <class Container>
308class front_insert_iterator
309    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
310{
311protected:
312    Container* container;
313public:
314    typedef Container                    container_type;
315    typedef void                         value_type;
316    typedef void                         difference_type; // until C++20
317    typedef ptrdiff_t                    difference_type; // since C++20
318    typedef void                         reference;
319    typedef void                         pointer;
320
321    explicit front_insert_iterator(Container& x);  // constexpr in C++20
322    front_insert_iterator& operator=(const typename Container::value_type& value);  // constexpr in C++20
323    front_insert_iterator& operator*();  // constexpr in C++20
324    front_insert_iterator& operator++();  // constexpr in C++20
325    front_insert_iterator  operator++(int);  // constexpr in C++20
326};
327
328template <class Container> front_insert_iterator<Container> front_inserter(Container& x);  // constexpr in C++20
329
330template <class Container>
331class insert_iterator
332    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
333{
334protected:
335    Container* container;
336    typename Container::iterator iter;
337public:
338    typedef Container              container_type;
339    typedef void                   value_type;
340    typedef void                   difference_type; // until C++20
341    typedef ptrdiff_t              difference_type; // since C++20
342    typedef void                   reference;
343    typedef void                   pointer;
344
345    insert_iterator(Container& x, typename Container::iterator i);  // constexpr in C++20
346    insert_iterator& operator=(const typename Container::value_type& value);  // constexpr in C++20
347    insert_iterator& operator*();  // constexpr in C++20
348    insert_iterator& operator++();  // constexpr in C++20
349    insert_iterator& operator++(int);  // constexpr in C++20
350};
351
352template <class Container>
353insert_iterator<Container> inserter(Container& x, typename Container::iterator i);  // until C++20
354template <class Container>
355constexpr insert_iterator<Container> inserter(Container& x, ranges::iterator_t<Container> i);  // since C++20
356
357template <class Iterator>
358class move_iterator {
359public:
360    typedef Iterator                                              iterator_type;
361    typedef typename iterator_traits<Iterator>::difference_type   difference_type;
362    typedef Iterator                                              pointer;
363    typedef typename iterator_traits<Iterator>::value_type        value_type;
364    typedef typename iterator_traits<Iterator>::iterator_category iterator_category;
365    typedef value_type&&                                          reference;
366
367    constexpr move_iterator();  // all the constexprs are in C++17
368    constexpr explicit move_iterator(Iterator i);
369    template <class U>
370      constexpr move_iterator(const move_iterator<U>& u);
371    template <class U>
372      constexpr move_iterator& operator=(const move_iterator<U>& u);
373    constexpr iterator_type base() const;
374    constexpr reference operator*() const;
375    constexpr pointer operator->() const;
376    constexpr move_iterator& operator++();
377    constexpr move_iterator operator++(int);
378    constexpr move_iterator& operator--();
379    constexpr move_iterator operator--(int);
380    constexpr move_iterator operator+(difference_type n) const;
381    constexpr move_iterator& operator+=(difference_type n);
382    constexpr move_iterator operator-(difference_type n) const;
383    constexpr move_iterator& operator-=(difference_type n);
384    constexpr unspecified operator[](difference_type n) const;
385private:
386    Iterator current; // exposition only
387};
388
389template <class Iterator1, class Iterator2>
390constexpr bool   // constexpr in C++17
391operator==(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
392
393template <class Iterator1, class Iterator2>
394constexpr bool   // constexpr in C++17
395operator!=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
396
397template <class Iterator1, class Iterator2>
398constexpr bool   // constexpr in C++17
399operator<(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
400
401template <class Iterator1, class Iterator2>
402constexpr bool   // constexpr in C++17
403operator<=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
404
405template <class Iterator1, class Iterator2>
406constexpr bool   // constexpr in C++17
407operator>(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
408
409template <class Iterator1, class Iterator2>
410constexpr bool   // constexpr in C++17
411operator>=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
412
413template <class Iterator1, class Iterator2>
414constexpr auto   // constexpr in C++17
415operator-(const move_iterator<Iterator1>& x,
416          const move_iterator<Iterator2>& y) -> decltype(x.base() - y.base());
417
418template <class Iterator>
419constexpr move_iterator<Iterator> operator+(   // constexpr in C++17
420            typename move_iterator<Iterator>::difference_type n,
421            const move_iterator<Iterator>& x);
422
423template <class Iterator>   // constexpr in C++17
424constexpr  move_iterator<Iterator> make_move_iterator(const Iterator& i);
425
426// [default.sentinel], default sentinel
427struct default_sentinel_t;
428inline constexpr default_sentinel_t default_sentinel{};
429
430// [iterators.counted], counted iterators
431template<input_or_output_iterator I> class counted_iterator;
432
433template<input_iterator I>
434  requires see below
435  struct iterator_traits<counted_iterator<I>>;
436
437// [unreachable.sentinel], unreachable sentinel
438struct unreachable_sentinel_t;
439inline constexpr unreachable_sentinel_t unreachable_sentinel{};
440
441template <class T, class charT = char, class traits = char_traits<charT>, class Distance = ptrdiff_t>
442class istream_iterator
443    : public iterator<input_iterator_tag, T, Distance, const T*, const T&> // until C++17
444{
445public:
446    typedef input_iterator_tag           iterator_category;
447    typedef T                            value_type;
448    typedef Distance                     difference_type;
449    typedef const T*                     pointer;
450    typedef const T&                     reference;
451
452    typedef charT                        char_type;
453    typedef traits                       traits_type;
454    typedef basic_istream<charT, traits> istream_type;
455
456    istream_iterator(); // constexpr since C++11
457    constexpr istream_iterator(default_sentinel_t); // since C++20
458    istream_iterator(istream_type& s);
459    istream_iterator(const istream_iterator& x);
460    ~istream_iterator();
461
462    const T& operator*() const;
463    const T* operator->() const;
464    istream_iterator& operator++();
465    istream_iterator  operator++(int);
466    friend bool operator==(const istream_iterator& i, default_sentinel_t); // since C++20
467};
468
469template <class T, class charT, class traits, class Distance>
470bool operator==(const istream_iterator<T,charT,traits,Distance>& x,
471                const istream_iterator<T,charT,traits,Distance>& y);
472template <class T, class charT, class traits, class Distance>
473bool operator!=(const istream_iterator<T,charT,traits,Distance>& x,
474                const istream_iterator<T,charT,traits,Distance>& y); // until C++20
475
476template <class T, class charT = char, class traits = char_traits<charT> >
477class ostream_iterator
478    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
479{
480public:
481    typedef output_iterator_tag         iterator_category;
482    typedef void                        value_type;
483    typedef void                        difference_type; // until C++20
484    typedef ptrdiff_t                   difference_type; // since C++20
485    typedef void                        pointer;
486    typedef void                        reference;
487
488    typedef charT char_type;
489    typedef traits traits_type;
490    typedef basic_ostream<charT,traits> ostream_type;
491
492    ostream_iterator(ostream_type& s);
493    ostream_iterator(ostream_type& s, const charT* delimiter);
494    ostream_iterator(const ostream_iterator& x);
495    ~ostream_iterator();
496    ostream_iterator& operator=(const T& value);
497
498    ostream_iterator& operator*();
499    ostream_iterator& operator++();
500    ostream_iterator& operator++(int);
501};
502
503template<class charT, class traits = char_traits<charT> >
504class istreambuf_iterator
505    : public iterator<input_iterator_tag, charT, traits::off_type, unspecified, charT> // until C++17
506{
507public:
508    typedef input_iterator_tag              iterator_category;
509    typedef charT                           value_type;
510    typedef traits::off_type                difference_type;
511    typedef unspecified                     pointer;
512    typedef charT                           reference;
513
514    typedef charT                           char_type;
515    typedef traits                          traits_type;
516    typedef traits::int_type                int_type;
517    typedef basic_streambuf<charT, traits>  streambuf_type;
518    typedef basic_istream<charT, traits>    istream_type;
519
520    istreambuf_iterator() noexcept; // constexpr since C++11
521    constexpr istreambuf_iterator(default_sentinel_t) noexcept; // since C++20
522    istreambuf_iterator(istream_type& s) noexcept;
523    istreambuf_iterator(streambuf_type* s) noexcept;
524    istreambuf_iterator(a-private-type) noexcept;
525
526    charT                operator*() const;
527    pointer operator->() const;
528    istreambuf_iterator& operator++();
529    a-private-type       operator++(int);
530
531    bool equal(const istreambuf_iterator& b) const;
532    friend bool operator==(const istreambuf_iterator& i, default_sentinel_t s); // since C++20
533};
534
535template <class charT, class traits>
536bool operator==(const istreambuf_iterator<charT,traits>& a,
537                const istreambuf_iterator<charT,traits>& b);
538template <class charT, class traits>
539bool operator!=(const istreambuf_iterator<charT,traits>& a,
540                const istreambuf_iterator<charT,traits>& b); // until C++20
541
542template <class charT, class traits = char_traits<charT> >
543class ostreambuf_iterator
544    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
545{
546public:
547    typedef output_iterator_tag            iterator_category;
548    typedef void                           value_type;
549    typedef void                           difference_type; // until C++20
550    typedef ptrdiff_t                      difference_type; // since C++20
551    typedef void                           pointer;
552    typedef void                           reference;
553
554    typedef charT                          char_type;
555    typedef traits                         traits_type;
556    typedef basic_streambuf<charT, traits> streambuf_type;
557    typedef basic_ostream<charT, traits>   ostream_type;
558
559    ostreambuf_iterator(ostream_type& s) noexcept;
560    ostreambuf_iterator(streambuf_type* s) noexcept;
561    ostreambuf_iterator& operator=(charT c);
562    ostreambuf_iterator& operator*();
563    ostreambuf_iterator& operator++();
564    ostreambuf_iterator& operator++(int);
565    bool failed() const noexcept;
566};
567
568template <class C> constexpr auto begin(C& c) -> decltype(c.begin());
569template <class C> constexpr auto begin(const C& c) -> decltype(c.begin());
570template <class C> constexpr auto end(C& c) -> decltype(c.end());
571template <class C> constexpr auto end(const C& c) -> decltype(c.end());
572template <class T, size_t N> constexpr T* begin(T (&array)[N]);
573template <class T, size_t N> constexpr T* end(T (&array)[N]);
574
575template <class C> auto constexpr cbegin(const C& c) -> decltype(std::begin(c));        // C++14
576template <class C> auto constexpr cend(const C& c) -> decltype(std::end(c));            // C++14
577template <class C> auto constexpr rbegin(C& c) -> decltype(c.rbegin());                 // C++14
578template <class C> auto constexpr rbegin(const C& c) -> decltype(c.rbegin());           // C++14
579template <class C> auto constexpr rend(C& c) -> decltype(c.rend());                     // C++14
580template <class C> constexpr auto rend(const C& c) -> decltype(c.rend());               // C++14
581template <class E> reverse_iterator<const E*> constexpr rbegin(initializer_list<E> il); // C++14
582template <class E> reverse_iterator<const E*> constexpr rend(initializer_list<E> il);   // C++14
583template <class T, size_t N> reverse_iterator<T*> constexpr rbegin(T (&array)[N]);      // C++14
584template <class T, size_t N> reverse_iterator<T*> constexpr rend(T (&array)[N]);        // C++14
585template <class C> constexpr auto crbegin(const C& c) -> decltype(std::rbegin(c));      // C++14
586template <class C> constexpr auto crend(const C& c) -> decltype(std::rend(c));          // C++14
587
588// 24.8, container access:
589template <class C> constexpr auto size(const C& c) -> decltype(c.size());         // C++17
590template <class T, size_t N> constexpr size_t size(const T (&array)[N]) noexcept; // C++17
591
592template <class C> constexpr auto ssize(const C& c)
593    -> common_type_t<ptrdiff_t, make_signed_t<decltype(c.size())>>;                    // C++20
594template <class T, ptrdiff_t> constexpr ptrdiff_t ssize(const T (&array)[N]) noexcept; // C++20
595
596template <class C> constexpr auto empty(const C& c) -> decltype(c.empty());       // C++17
597template <class T, size_t N> constexpr bool empty(const T (&array)[N]) noexcept;  // C++17
598template <class E> constexpr bool empty(initializer_list<E> il) noexcept;         // C++17
599template <class C> constexpr auto data(C& c) -> decltype(c.data());               // C++17
600template <class C> constexpr auto data(const C& c) -> decltype(c.data());         // C++17
601template <class T, size_t N> constexpr T* data(T (&array)[N]) noexcept;           // C++17
602template <class E> constexpr const E* data(initializer_list<E> il) noexcept;      // C++17
603
604}  // std
605
606*/
607
608#include <__config>
609#include <__debug>
610#include <__iterator/access.h>
611#include <__iterator/advance.h>
612#include <__iterator/back_insert_iterator.h>
613#include <__iterator/common_iterator.h>
614#include <__iterator/concepts.h>
615#include <__iterator/counted_iterator.h>
616#include <__iterator/data.h>
617#include <__iterator/default_sentinel.h>
618#include <__iterator/distance.h>
619#include <__iterator/empty.h>
620#include <__iterator/erase_if_container.h>
621#include <__iterator/front_insert_iterator.h>
622#include <__iterator/incrementable_traits.h>
623#include <__iterator/indirectly_comparable.h>
624#include <__iterator/insert_iterator.h>
625#include <__iterator/istream_iterator.h>
626#include <__iterator/istreambuf_iterator.h>
627#include <__iterator/iter_move.h>
628#include <__iterator/iter_swap.h>
629#include <__iterator/iterator.h>
630#include <__iterator/iterator_traits.h>
631#include <__iterator/mergeable.h>
632#include <__iterator/move_iterator.h>
633#include <__iterator/next.h>
634#include <__iterator/ostream_iterator.h>
635#include <__iterator/ostreambuf_iterator.h>
636#include <__iterator/permutable.h>
637#include <__iterator/prev.h>
638#include <__iterator/projected.h>
639#include <__iterator/readable_traits.h>
640#include <__iterator/reverse_access.h>
641#include <__iterator/reverse_iterator.h>
642#include <__iterator/size.h>
643#include <__iterator/unreachable_sentinel.h>
644#include <__iterator/wrap_iter.h>
645#include <__memory/addressof.h>
646#include <__memory/pointer_traits.h>
647#include <compare>
648#include <concepts> // Mandated by the Standard.
649#include <cstddef>
650#include <initializer_list>
651#include <type_traits>
652#include <utility>
653#include <version>
654
655// TODO: remove these headers
656#include <__functional/binary_function.h>
657#include <__functional/invoke.h>
658#include <__functional/operations.h>
659#include <__functional/reference_wrapper.h>
660#include <__functional/unary_function.h>
661#include <__functional/weak_result_type.h>
662#include <__memory/allocator_arg_t.h>
663#include <__memory/uses_allocator.h>
664#include <exception>
665#include <new>
666#include <typeinfo>
667
668#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
669#  pragma GCC system_header
670#endif
671
672#endif // _LIBCPP_ITERATOR
673