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    typedef Iterator                                            iterator_type;
229    typedef typename iterator_traits<Iterator>::difference_type difference_type;
230    typedef typename iterator_traits<Iterator>::reference       reference;
231    typedef typename iterator_traits<Iterator>::pointer         pointer;
232
233    constexpr reverse_iterator();
234    constexpr explicit reverse_iterator(Iterator x);
235    template <class U> constexpr reverse_iterator(const reverse_iterator<U>& u);
236    template <class U> constexpr reverse_iterator& operator=(const reverse_iterator<U>& u);
237    constexpr Iterator base() const;
238    constexpr reference operator*() const;
239    constexpr pointer   operator->() const;
240    constexpr reverse_iterator& operator++();
241    constexpr reverse_iterator  operator++(int);
242    constexpr reverse_iterator& operator--();
243    constexpr reverse_iterator  operator--(int);
244    constexpr reverse_iterator  operator+ (difference_type n) const;
245    constexpr reverse_iterator& operator+=(difference_type n);
246    constexpr reverse_iterator  operator- (difference_type n) const;
247    constexpr reverse_iterator& operator-=(difference_type n);
248    constexpr reference         operator[](difference_type n) const;
249};
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 bool                          // constexpr in C++17
273operator<=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
274
275template <class Iterator1, class Iterator2>
276constexpr auto
277operator-(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y)
278-> decltype(__y.base() - __x.base());   // constexpr in C++17
279
280template <class Iterator>
281constexpr reverse_iterator<Iterator>
282operator+(typename reverse_iterator<Iterator>::difference_type n,
283          const reverse_iterator<Iterator>& x);   // constexpr in C++17
284
285template <class Iterator>
286constexpr reverse_iterator<Iterator> make_reverse_iterator(Iterator i); // C++14, constexpr in C++17
287
288template <class Container>
289class back_insert_iterator
290    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
291{
292protected:
293    Container* container;
294public:
295    typedef Container                   container_type;
296    typedef void                        value_type;
297    typedef void                        difference_type; // until C++20
298    typedef ptrdiff_t                   difference_type; // since C++20
299    typedef void                        reference;
300    typedef void                        pointer;
301
302    explicit back_insert_iterator(Container& x);  // constexpr in C++20
303    back_insert_iterator& operator=(const typename Container::value_type& value);  // constexpr in C++20
304    back_insert_iterator& operator*();  // constexpr in C++20
305    back_insert_iterator& operator++();  // constexpr in C++20
306    back_insert_iterator  operator++(int);  // constexpr in C++20
307};
308
309template <class Container> back_insert_iterator<Container> back_inserter(Container& x);  // constexpr in C++20
310
311template <class Container>
312class front_insert_iterator
313    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
314{
315protected:
316    Container* container;
317public:
318    typedef Container                    container_type;
319    typedef void                         value_type;
320    typedef void                         difference_type; // until C++20
321    typedef ptrdiff_t                    difference_type; // since C++20
322    typedef void                         reference;
323    typedef void                         pointer;
324
325    explicit front_insert_iterator(Container& x);  // constexpr in C++20
326    front_insert_iterator& operator=(const typename Container::value_type& value);  // constexpr in C++20
327    front_insert_iterator& operator*();  // constexpr in C++20
328    front_insert_iterator& operator++();  // constexpr in C++20
329    front_insert_iterator  operator++(int);  // constexpr in C++20
330};
331
332template <class Container> front_insert_iterator<Container> front_inserter(Container& x);  // constexpr in C++20
333
334template <class Container>
335class insert_iterator
336    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
337{
338protected:
339    Container* container;
340    typename Container::iterator iter;
341public:
342    typedef Container              container_type;
343    typedef void                   value_type;
344    typedef void                   difference_type; // until C++20
345    typedef ptrdiff_t              difference_type; // since C++20
346    typedef void                   reference;
347    typedef void                   pointer;
348
349    insert_iterator(Container& x, typename Container::iterator i);  // constexpr in C++20
350    insert_iterator& operator=(const typename Container::value_type& value);  // constexpr in C++20
351    insert_iterator& operator*();  // constexpr in C++20
352    insert_iterator& operator++();  // constexpr in C++20
353    insert_iterator& operator++(int);  // constexpr in C++20
354};
355
356template <class Container>
357insert_iterator<Container> inserter(Container& x, typename Container::iterator i);  // until C++20
358template <class Container>
359constexpr insert_iterator<Container> inserter(Container& x, ranges::iterator_t<Container> i);  // since C++20
360
361template <class Iterator>
362class move_iterator {
363public:
364    typedef Iterator                                              iterator_type;
365    typedef typename iterator_traits<Iterator>::difference_type   difference_type;
366    typedef Iterator                                              pointer;
367    typedef typename iterator_traits<Iterator>::value_type        value_type;
368    typedef typename iterator_traits<Iterator>::iterator_category iterator_category;
369    typedef value_type&&                                          reference;
370
371    constexpr move_iterator();  // all the constexprs are in C++17
372    constexpr explicit move_iterator(Iterator i);
373    template <class U>
374      constexpr move_iterator(const move_iterator<U>& u);
375    template <class U>
376      constexpr move_iterator& operator=(const move_iterator<U>& u);
377    constexpr iterator_type base() const;
378    constexpr reference operator*() const;
379    constexpr pointer operator->() const;
380    constexpr move_iterator& operator++();
381    constexpr move_iterator operator++(int);
382    constexpr move_iterator& operator--();
383    constexpr move_iterator operator--(int);
384    constexpr move_iterator operator+(difference_type n) const;
385    constexpr move_iterator& operator+=(difference_type n);
386    constexpr move_iterator operator-(difference_type n) const;
387    constexpr move_iterator& operator-=(difference_type n);
388    constexpr unspecified operator[](difference_type n) const;
389private:
390    Iterator current; // exposition only
391};
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 bool   // constexpr in C++17
415operator>=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
416
417template <class Iterator1, class Iterator2>
418constexpr auto   // constexpr in C++17
419operator-(const move_iterator<Iterator1>& x,
420          const move_iterator<Iterator2>& y) -> decltype(x.base() - y.base());
421
422template <class Iterator>
423constexpr move_iterator<Iterator> operator+(   // constexpr in C++17
424            typename move_iterator<Iterator>::difference_type n,
425            const move_iterator<Iterator>& x);
426
427template <class Iterator>   // constexpr in C++17
428constexpr  move_iterator<Iterator> make_move_iterator(const Iterator& i);
429
430// [default.sentinel], default sentinel
431struct default_sentinel_t;
432inline constexpr default_sentinel_t default_sentinel{};
433
434// [iterators.counted], counted iterators
435template<input_or_output_iterator I> class counted_iterator;
436
437template<input_iterator I>
438  requires see below
439  struct iterator_traits<counted_iterator<I>>;
440
441// [unreachable.sentinel], unreachable sentinel
442struct unreachable_sentinel_t;
443inline constexpr unreachable_sentinel_t unreachable_sentinel{};
444
445template <class T, class charT = char, class traits = char_traits<charT>, class Distance = ptrdiff_t>
446class istream_iterator
447    : public iterator<input_iterator_tag, T, Distance, const T*, const T&> // until C++17
448{
449public:
450    typedef input_iterator_tag           iterator_category;
451    typedef T                            value_type;
452    typedef Distance                     difference_type;
453    typedef const T*                     pointer;
454    typedef const T&                     reference;
455
456    typedef charT                        char_type;
457    typedef traits                       traits_type;
458    typedef basic_istream<charT, traits> istream_type;
459
460    istream_iterator(); // constexpr since C++11
461    constexpr istream_iterator(default_sentinel_t); // since C++20
462    istream_iterator(istream_type& s);
463    istream_iterator(const istream_iterator& x);
464    ~istream_iterator();
465
466    const T& operator*() const;
467    const T* operator->() const;
468    istream_iterator& operator++();
469    istream_iterator  operator++(int);
470    friend bool operator==(const istream_iterator& i, default_sentinel_t); // since C++20
471};
472
473template <class T, class charT, class traits, class Distance>
474bool operator==(const istream_iterator<T,charT,traits,Distance>& x,
475                const istream_iterator<T,charT,traits,Distance>& y);
476template <class T, class charT, class traits, class Distance>
477bool operator!=(const istream_iterator<T,charT,traits,Distance>& x,
478                const istream_iterator<T,charT,traits,Distance>& y); // until C++20
479
480template <class T, class charT = char, class traits = char_traits<charT> >
481class ostream_iterator
482    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
483{
484public:
485    typedef output_iterator_tag         iterator_category;
486    typedef void                        value_type;
487    typedef void                        difference_type; // until C++20
488    typedef ptrdiff_t                   difference_type; // since C++20
489    typedef void                        pointer;
490    typedef void                        reference;
491
492    typedef charT char_type;
493    typedef traits traits_type;
494    typedef basic_ostream<charT,traits> ostream_type;
495
496    ostream_iterator(ostream_type& s);
497    ostream_iterator(ostream_type& s, const charT* delimiter);
498    ostream_iterator(const ostream_iterator& x);
499    ~ostream_iterator();
500    ostream_iterator& operator=(const T& value);
501
502    ostream_iterator& operator*();
503    ostream_iterator& operator++();
504    ostream_iterator& operator++(int);
505};
506
507template<class charT, class traits = char_traits<charT> >
508class istreambuf_iterator
509    : public iterator<input_iterator_tag, charT, traits::off_type, unspecified, charT> // until C++17
510{
511public:
512    typedef input_iterator_tag              iterator_category;
513    typedef charT                           value_type;
514    typedef traits::off_type                difference_type;
515    typedef unspecified                     pointer;
516    typedef charT                           reference;
517
518    typedef charT                           char_type;
519    typedef traits                          traits_type;
520    typedef traits::int_type                int_type;
521    typedef basic_streambuf<charT, traits>  streambuf_type;
522    typedef basic_istream<charT, traits>    istream_type;
523
524    istreambuf_iterator() noexcept; // constexpr since C++11
525    constexpr istreambuf_iterator(default_sentinel_t) noexcept; // since C++20
526    istreambuf_iterator(istream_type& s) noexcept;
527    istreambuf_iterator(streambuf_type* s) noexcept;
528    istreambuf_iterator(a-private-type) noexcept;
529
530    charT                operator*() const;
531    pointer operator->() const;
532    istreambuf_iterator& operator++();
533    a-private-type       operator++(int);
534
535    bool equal(const istreambuf_iterator& b) const;
536    friend bool operator==(const istreambuf_iterator& i, default_sentinel_t s); // since C++20
537};
538
539template <class charT, class traits>
540bool operator==(const istreambuf_iterator<charT,traits>& a,
541                const istreambuf_iterator<charT,traits>& b);
542template <class charT, class traits>
543bool operator!=(const istreambuf_iterator<charT,traits>& a,
544                const istreambuf_iterator<charT,traits>& b); // until C++20
545
546template <class charT, class traits = char_traits<charT> >
547class ostreambuf_iterator
548    : public iterator<output_iterator_tag, void, void, void, void> // until C++17
549{
550public:
551    typedef output_iterator_tag            iterator_category;
552    typedef void                           value_type;
553    typedef void                           difference_type; // until C++20
554    typedef ptrdiff_t                      difference_type; // since C++20
555    typedef void                           pointer;
556    typedef void                           reference;
557
558    typedef charT                          char_type;
559    typedef traits                         traits_type;
560    typedef basic_streambuf<charT, traits> streambuf_type;
561    typedef basic_ostream<charT, traits>   ostream_type;
562
563    ostreambuf_iterator(ostream_type& s) noexcept;
564    ostreambuf_iterator(streambuf_type* s) noexcept;
565    ostreambuf_iterator& operator=(charT c);
566    ostreambuf_iterator& operator*();
567    ostreambuf_iterator& operator++();
568    ostreambuf_iterator& operator++(int);
569    bool failed() const noexcept;
570};
571
572template <class C> constexpr auto begin(C& c) -> decltype(c.begin());
573template <class C> constexpr auto begin(const C& c) -> decltype(c.begin());
574template <class C> constexpr auto end(C& c) -> decltype(c.end());
575template <class C> constexpr auto end(const C& c) -> decltype(c.end());
576template <class T, size_t N> constexpr T* begin(T (&array)[N]);
577template <class T, size_t N> constexpr T* end(T (&array)[N]);
578
579template <class C> auto constexpr cbegin(const C& c) -> decltype(std::begin(c));        // C++14
580template <class C> auto constexpr cend(const C& c) -> decltype(std::end(c));            // C++14
581template <class C> auto constexpr rbegin(C& c) -> decltype(c.rbegin());                 // C++14
582template <class C> auto constexpr rbegin(const C& c) -> decltype(c.rbegin());           // C++14
583template <class C> auto constexpr rend(C& c) -> decltype(c.rend());                     // C++14
584template <class C> constexpr auto rend(const C& c) -> decltype(c.rend());               // C++14
585template <class E> reverse_iterator<const E*> constexpr rbegin(initializer_list<E> il); // C++14
586template <class E> reverse_iterator<const E*> constexpr rend(initializer_list<E> il);   // C++14
587template <class T, size_t N> reverse_iterator<T*> constexpr rbegin(T (&array)[N]);      // C++14
588template <class T, size_t N> reverse_iterator<T*> constexpr rend(T (&array)[N]);        // C++14
589template <class C> constexpr auto crbegin(const C& c) -> decltype(std::rbegin(c));      // C++14
590template <class C> constexpr auto crend(const C& c) -> decltype(std::rend(c));          // C++14
591
592// 24.8, container access:
593template <class C> constexpr auto size(const C& c) -> decltype(c.size());         // C++17
594template <class T, size_t N> constexpr size_t size(const T (&array)[N]) noexcept; // C++17
595
596template <class C> constexpr auto ssize(const C& c)
597    -> common_type_t<ptrdiff_t, make_signed_t<decltype(c.size())>>;                    // C++20
598template <class T, ptrdiff_t> constexpr ptrdiff_t ssize(const T (&array)[N]) noexcept; // C++20
599
600template <class C> constexpr auto empty(const C& c) -> decltype(c.empty());       // C++17
601template <class T, size_t N> constexpr bool empty(const T (&array)[N]) noexcept;  // C++17
602template <class E> constexpr bool empty(initializer_list<E> il) noexcept;         // C++17
603template <class C> constexpr auto data(C& c) -> decltype(c.data());               // C++17
604template <class C> constexpr auto data(const C& c) -> decltype(c.data());         // C++17
605template <class T, size_t N> constexpr T* data(T (&array)[N]) noexcept;           // C++17
606template <class E> constexpr const E* data(initializer_list<E> il) noexcept;      // C++17
607
608}  // std
609
610*/
611
612#include <__config>
613#include <__debug>
614#include <__iterator/access.h>
615#include <__iterator/advance.h>
616#include <__iterator/back_insert_iterator.h>
617#include <__iterator/common_iterator.h>
618#include <__iterator/concepts.h>
619#include <__iterator/counted_iterator.h>
620#include <__iterator/data.h>
621#include <__iterator/default_sentinel.h>
622#include <__iterator/distance.h>
623#include <__iterator/empty.h>
624#include <__iterator/erase_if_container.h>
625#include <__iterator/front_insert_iterator.h>
626#include <__iterator/incrementable_traits.h>
627#include <__iterator/indirectly_comparable.h>
628#include <__iterator/insert_iterator.h>
629#include <__iterator/istream_iterator.h>
630#include <__iterator/istreambuf_iterator.h>
631#include <__iterator/iter_move.h>
632#include <__iterator/iter_swap.h>
633#include <__iterator/iterator.h>
634#include <__iterator/iterator_traits.h>
635#include <__iterator/mergeable.h>
636#include <__iterator/move_iterator.h>
637#include <__iterator/next.h>
638#include <__iterator/ostream_iterator.h>
639#include <__iterator/ostreambuf_iterator.h>
640#include <__iterator/permutable.h>
641#include <__iterator/prev.h>
642#include <__iterator/projected.h>
643#include <__iterator/readable_traits.h>
644#include <__iterator/reverse_access.h>
645#include <__iterator/reverse_iterator.h>
646#include <__iterator/size.h>
647#include <__iterator/sortable.h>
648#include <__iterator/unreachable_sentinel.h>
649#include <__iterator/wrap_iter.h>
650#include <__memory/addressof.h>
651#include <__memory/pointer_traits.h>
652#include <compare>
653#include <concepts> // Mandated by the Standard.
654#include <cstddef>
655#include <initializer_list>
656#include <type_traits>
657#include <version>
658
659#include <utility> // TODO: Remove this
660
661// TODO: remove these headers
662#include <__functional/binary_function.h>
663#include <__functional/invoke.h>
664#include <__functional/operations.h>
665#include <__functional/reference_wrapper.h>
666#include <__functional/unary_function.h>
667#include <__functional/weak_result_type.h>
668#include <__memory/allocator_arg_t.h>
669#include <__memory/uses_allocator.h>
670#include <exception>
671#include <new>
672#include <typeinfo>
673
674#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
675#  pragma GCC system_header
676#endif
677
678#endif // _LIBCPP_ITERATOR
679