xref: /freebsd/contrib/llvm-project/libcxx/include/iterator (revision c66ec88fed842fbaad62c30d510644ceb7bd2d71) 
1// -*- C++ -*-
2//===-------------------------- iterator ----------------------------------===//
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
16namespace std
17{
18
19template<class Iterator>
20struct iterator_traits
21{
22    typedef typename Iterator::difference_type difference_type;
23    typedef typename Iterator::value_type value_type;
24    typedef typename Iterator::pointer pointer;
25    typedef typename Iterator::reference reference;
26    typedef typename Iterator::iterator_category iterator_category;
27};
28
29template<class T>
30struct iterator_traits<T*>
31{
32    typedef ptrdiff_t difference_type;
33    typedef T value_type;
34    typedef T* pointer;
35    typedef T& reference;
36    typedef random_access_iterator_tag iterator_category;
37};
38
39template<class Category, class T, class Distance = ptrdiff_t,
40         class Pointer = T*, class Reference = T&>
41struct iterator
42{
43    typedef T         value_type;
44    typedef Distance  difference_type;
45    typedef Pointer   pointer;
46    typedef Reference reference;
47    typedef Category  iterator_category;
48};
49
50struct input_iterator_tag  {};
51struct output_iterator_tag {};
52struct forward_iterator_tag       : public input_iterator_tag         {};
53struct bidirectional_iterator_tag : public forward_iterator_tag       {};
54struct random_access_iterator_tag : public bidirectional_iterator_tag {};
55
56// 27.4.3, iterator operations
57template <class InputIterator, class Distance>  // constexpr in C++17
58  constexpr void advance(InputIterator& i, Distance n);
59
60template <class InputIterator>  // constexpr in C++17
61  constexpr typename iterator_traits<InputIterator>::difference_type
62    distance(InputIterator first, InputIterator last);
63
64template <class InputIterator>  // constexpr in C++17
65  constexpr InputIterator next(InputIterator x,
66typename iterator_traits<InputIterator>::difference_type n = 1);
67
68template <class BidirectionalIterator>  // constexpr in C++17
69  constexpr BidirectionalIterator prev(BidirectionalIterator x,
70    typename iterator_traits<BidirectionalIterator>::difference_type n = 1);
71
72template <class Iterator>
73class reverse_iterator
74    : public iterator<typename iterator_traits<Iterator>::iterator_category,
75                      typename iterator_traits<Iterator>::value_type,
76                      typename iterator_traits<Iterator>::difference_type,
77                      typename iterator_traits<Iterator>::pointer,
78                      typename iterator_traits<Iterator>::reference>
79{
80protected:
81    Iterator current;
82public:
83    typedef Iterator                                            iterator_type;
84    typedef typename iterator_traits<Iterator>::difference_type difference_type;
85    typedef typename iterator_traits<Iterator>::reference       reference;
86    typedef typename iterator_traits<Iterator>::pointer         pointer;
87
88    constexpr reverse_iterator();
89    constexpr explicit reverse_iterator(Iterator x);
90    template <class U> constexpr reverse_iterator(const reverse_iterator<U>& u);
91    template <class U> constexpr reverse_iterator& operator=(const reverse_iterator<U>& u);
92    constexpr Iterator base() const;
93    constexpr reference operator*() const;
94    constexpr pointer   operator->() const;
95    constexpr reverse_iterator& operator++();
96    constexpr reverse_iterator  operator++(int);
97    constexpr reverse_iterator& operator--();
98    constexpr reverse_iterator  operator--(int);
99    constexpr reverse_iterator  operator+ (difference_type n) const;
100    constexpr reverse_iterator& operator+=(difference_type n);
101    constexpr reverse_iterator  operator- (difference_type n) const;
102    constexpr reverse_iterator& operator-=(difference_type n);
103    constexpr reference         operator[](difference_type n) const;
104};
105
106template <class Iterator1, class Iterator2>
107constexpr bool                          // constexpr in C++17
108operator==(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
109
110template <class Iterator1, class Iterator2>
111constexpr bool                          // constexpr in C++17
112operator<(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
113
114template <class Iterator1, class Iterator2>
115constexpr bool                          // constexpr in C++17
116operator!=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
117
118template <class Iterator1, class Iterator2>
119constexpr bool                          // constexpr in C++17
120operator>(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
121
122template <class Iterator1, class Iterator2>
123constexpr bool                          // constexpr in C++17
124operator>=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
125
126template <class Iterator1, class Iterator2>
127constexpr bool                          // constexpr in C++17
128operator<=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
129
130template <class Iterator1, class Iterator2>
131constexpr auto
132operator-(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y)
133-> decltype(__y.base() - __x.base());   // constexpr in C++17
134
135template <class Iterator>
136constexpr reverse_iterator<Iterator>
137operator+(typename reverse_iterator<Iterator>::difference_type n,
138          const reverse_iterator<Iterator>& x);   // constexpr in C++17
139
140template <class Iterator>
141constexpr reverse_iterator<Iterator> make_reverse_iterator(Iterator i); // C++14, constexpr in C++17
142
143template <class Container>
144class back_insert_iterator
145{
146protected:
147    Container* container;
148public:
149    typedef Container                   container_type;
150    typedef void                        value_type;
151    typedef void                        difference_type;
152    typedef void                        reference;
153    typedef void                        pointer;
154
155    explicit back_insert_iterator(Container& x);
156    back_insert_iterator& operator=(const typename Container::value_type& value);
157    back_insert_iterator& operator*();
158    back_insert_iterator& operator++();
159    back_insert_iterator  operator++(int);
160};
161
162template <class Container> back_insert_iterator<Container> back_inserter(Container& x);
163
164template <class Container>
165class front_insert_iterator
166{
167protected:
168    Container* container;
169public:
170    typedef Container                    container_type;
171    typedef void                         value_type;
172    typedef void                         difference_type;
173    typedef void                         reference;
174    typedef void                         pointer;
175
176    explicit front_insert_iterator(Container& x);
177    front_insert_iterator& operator=(const typename Container::value_type& value);
178    front_insert_iterator& operator*();
179    front_insert_iterator& operator++();
180    front_insert_iterator  operator++(int);
181};
182
183template <class Container> front_insert_iterator<Container> front_inserter(Container& x);
184
185template <class Container>
186class insert_iterator
187{
188protected:
189    Container* container;
190    typename Container::iterator iter;
191public:
192    typedef Container              container_type;
193    typedef void                   value_type;
194    typedef void                   difference_type;
195    typedef void                   reference;
196    typedef void                   pointer;
197
198    insert_iterator(Container& x, typename Container::iterator i);
199    insert_iterator& operator=(const typename Container::value_type& value);
200    insert_iterator& operator*();
201    insert_iterator& operator++();
202    insert_iterator& operator++(int);
203};
204
205template <class Container, class Iterator>
206insert_iterator<Container> inserter(Container& x, Iterator i);
207
208template <class Iterator>
209class move_iterator {
210public:
211    typedef Iterator                                              iterator_type;
212    typedef typename iterator_traits<Iterator>::difference_type   difference_type;
213    typedef Iterator                                              pointer;
214    typedef typename iterator_traits<Iterator>::value_type        value_type;
215    typedef typename iterator_traits<Iterator>::iterator_category iterator_category;
216    typedef value_type&&                                          reference;
217
218    constexpr move_iterator();  // all the constexprs are in C++17
219    constexpr explicit move_iterator(Iterator i);
220    template <class U>
221      constexpr move_iterator(const move_iterator<U>& u);
222    template <class U>
223      constexpr move_iterator& operator=(const move_iterator<U>& u);
224    constexpr iterator_type base() const;
225    constexpr reference operator*() const;
226    constexpr pointer operator->() const;
227    constexpr move_iterator& operator++();
228    constexpr move_iterator operator++(int);
229    constexpr move_iterator& operator--();
230    constexpr move_iterator operator--(int);
231    constexpr move_iterator operator+(difference_type n) const;
232    constexpr move_iterator& operator+=(difference_type n);
233    constexpr move_iterator operator-(difference_type n) const;
234    constexpr move_iterator& operator-=(difference_type n);
235    constexpr unspecified operator[](difference_type n) const;
236private:
237    Iterator current; // exposition only
238};
239
240template <class Iterator1, class Iterator2>
241constexpr bool   // constexpr in C++17
242operator==(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
243
244template <class Iterator1, class Iterator2>
245constexpr bool   // constexpr in C++17
246operator!=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
247
248template <class Iterator1, class Iterator2>
249constexpr bool   // constexpr in C++17
250operator<(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
251
252template <class Iterator1, class Iterator2>
253constexpr bool   // constexpr in C++17
254operator<=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
255
256template <class Iterator1, class Iterator2>
257constexpr bool   // constexpr in C++17
258operator>(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
259
260template <class Iterator1, class Iterator2>
261constexpr bool   // constexpr in C++17
262operator>=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
263
264template <class Iterator1, class Iterator2>
265constexpr auto   // constexpr in C++17
266operator-(const move_iterator<Iterator1>& x,
267          const move_iterator<Iterator2>& y) -> decltype(x.base() - y.base());
268
269template <class Iterator>
270constexpr move_iterator<Iterator> operator+(   // constexpr in C++17
271            typename move_iterator<Iterator>::difference_type n,
272            const move_iterator<Iterator>& x);
273
274template <class Iterator>   // constexpr in C++17
275constexpr  move_iterator<Iterator> make_move_iterator(const Iterator& i);
276
277
278template <class T, class charT = char, class traits = char_traits<charT>, class Distance = ptrdiff_t>
279class istream_iterator
280    : public iterator<input_iterator_tag, T, Distance, const T*, const T&>
281{
282public:
283    typedef charT char_type;
284    typedef traits traits_type;
285    typedef basic_istream<charT,traits> istream_type;
286
287    constexpr istream_iterator();
288    istream_iterator(istream_type& s);
289    istream_iterator(const istream_iterator& x);
290    ~istream_iterator();
291
292    const T& operator*() const;
293    const T* operator->() const;
294    istream_iterator& operator++();
295    istream_iterator  operator++(int);
296};
297
298template <class T, class charT, class traits, class Distance>
299bool operator==(const istream_iterator<T,charT,traits,Distance>& x,
300                const istream_iterator<T,charT,traits,Distance>& y);
301template <class T, class charT, class traits, class Distance>
302bool operator!=(const istream_iterator<T,charT,traits,Distance>& x,
303                const istream_iterator<T,charT,traits,Distance>& y);
304
305template <class T, class charT = char, class traits = char_traits<charT> >
306class ostream_iterator
307    : public iterator<output_iterator_tag, void, void, void ,void>
308{
309public:
310    typedef charT char_type;
311    typedef traits traits_type;
312    typedef basic_ostream<charT,traits> ostream_type;
313
314    ostream_iterator(ostream_type& s);
315    ostream_iterator(ostream_type& s, const charT* delimiter);
316    ostream_iterator(const ostream_iterator& x);
317    ~ostream_iterator();
318    ostream_iterator& operator=(const T& value);
319
320    ostream_iterator& operator*();
321    ostream_iterator& operator++();
322    ostream_iterator& operator++(int);
323};
324
325template<class charT, class traits = char_traits<charT> >
326class istreambuf_iterator
327    : public iterator<input_iterator_tag, charT,
328                      typename traits::off_type, unspecified,
329                      charT>
330{
331public:
332    typedef charT                         char_type;
333    typedef traits                        traits_type;
334    typedef typename traits::int_type     int_type;
335    typedef basic_streambuf<charT,traits> streambuf_type;
336    typedef basic_istream<charT,traits>   istream_type;
337
338    istreambuf_iterator() noexcept;
339    istreambuf_iterator(istream_type& s) noexcept;
340    istreambuf_iterator(streambuf_type* s) noexcept;
341    istreambuf_iterator(a-private-type) noexcept;
342
343    charT                operator*() const;
344    pointer operator->() const;
345    istreambuf_iterator& operator++();
346    a-private-type       operator++(int);
347
348    bool equal(const istreambuf_iterator& b) const;
349};
350
351template <class charT, class traits>
352bool operator==(const istreambuf_iterator<charT,traits>& a,
353                const istreambuf_iterator<charT,traits>& b);
354template <class charT, class traits>
355bool operator!=(const istreambuf_iterator<charT,traits>& a,
356                const istreambuf_iterator<charT,traits>& b);
357
358template <class charT, class traits = char_traits<charT> >
359class ostreambuf_iterator
360    : public iterator<output_iterator_tag, void, void, void, void>
361{
362public:
363    typedef charT                         char_type;
364    typedef traits                        traits_type;
365    typedef basic_streambuf<charT,traits> streambuf_type;
366    typedef basic_ostream<charT,traits>   ostream_type;
367
368    ostreambuf_iterator(ostream_type& s) noexcept;
369    ostreambuf_iterator(streambuf_type* s) noexcept;
370    ostreambuf_iterator& operator=(charT c);
371    ostreambuf_iterator& operator*();
372    ostreambuf_iterator& operator++();
373    ostreambuf_iterator& operator++(int);
374    bool failed() const noexcept;
375};
376
377template <class C> constexpr auto begin(C& c) -> decltype(c.begin());
378template <class C> constexpr auto begin(const C& c) -> decltype(c.begin());
379template <class C> constexpr auto end(C& c) -> decltype(c.end());
380template <class C> constexpr auto end(const C& c) -> decltype(c.end());
381template <class T, size_t N> constexpr T* begin(T (&array)[N]);
382template <class T, size_t N> constexpr T* end(T (&array)[N]);
383
384template <class C> auto constexpr cbegin(const C& c) -> decltype(std::begin(c));        // C++14
385template <class C> auto constexpr cend(const C& c) -> decltype(std::end(c));            // C++14
386template <class C> auto constexpr rbegin(C& c) -> decltype(c.rbegin());                 // C++14
387template <class C> auto constexpr rbegin(const C& c) -> decltype(c.rbegin());           // C++14
388template <class C> auto constexpr rend(C& c) -> decltype(c.rend());                     // C++14
389template <class C> constexpr auto rend(const C& c) -> decltype(c.rend());               // C++14
390template <class E> reverse_iterator<const E*> constexpr rbegin(initializer_list<E> il); // C++14
391template <class E> reverse_iterator<const E*> constexpr rend(initializer_list<E> il);   // C++14
392template <class T, size_t N> reverse_iterator<T*> constexpr rbegin(T (&array)[N]);      // C++14
393template <class T, size_t N> reverse_iterator<T*> constexpr rend(T (&array)[N]);        // C++14
394template <class C> constexpr auto crbegin(const C& c) -> decltype(std::rbegin(c));      // C++14
395template <class C> constexpr auto crend(const C& c) -> decltype(std::rend(c));          // C++14
396
397// 24.8, container access:
398template <class C> constexpr auto size(const C& c) -> decltype(c.size());         // C++17
399template <class T, size_t N> constexpr size_t size(const T (&array)[N]) noexcept; // C++17
400
401template <class C> constexpr auto ssize(const C& c)
402    -> common_type_t<ptrdiff_t, make_signed_t<decltype(c.size())>>;				       // C++20
403template <class T, ptrdiff_t> constexpr ptrdiff_t ssize(const T (&array)[N]) noexcept; // C++20
404
405template <class C> constexpr auto empty(const C& c) -> decltype(c.empty());       // C++17
406template <class T, size_t N> constexpr bool empty(const T (&array)[N]) noexcept;  // C++17
407template <class E> constexpr bool empty(initializer_list<E> il) noexcept;         // C++17
408template <class C> constexpr auto data(C& c) -> decltype(c.data());               // C++17
409template <class C> constexpr auto data(const C& c) -> decltype(c.data());         // C++17
410template <class T, size_t N> constexpr T* data(T (&array)[N]) noexcept;           // C++17
411template <class E> constexpr const E* data(initializer_list<E> il) noexcept;      // C++17
412
413}  // std
414
415*/
416
417#include <__config>
418#include <iosfwd> // for forward declarations of vector and string.
419#include <__functional_base>
420#include <type_traits>
421#include <cstddef>
422#include <initializer_list>
423#include <version>
424#ifdef __APPLE__
425#include <Availability.h>
426#endif
427
428#include <__debug>
429
430#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
431#pragma GCC system_header
432#endif
433
434_LIBCPP_BEGIN_NAMESPACE_STD
435template <class _Iter>
436struct _LIBCPP_TEMPLATE_VIS iterator_traits;
437
438struct _LIBCPP_TEMPLATE_VIS input_iterator_tag {};
439struct _LIBCPP_TEMPLATE_VIS output_iterator_tag {};
440struct _LIBCPP_TEMPLATE_VIS forward_iterator_tag       : public input_iterator_tag {};
441struct _LIBCPP_TEMPLATE_VIS bidirectional_iterator_tag : public forward_iterator_tag {};
442struct _LIBCPP_TEMPLATE_VIS random_access_iterator_tag : public bidirectional_iterator_tag {};
443#if _LIBCPP_STD_VER > 17
444// TODO(EricWF)  contiguous_iterator_tag is provided as an extension prior to
445//  C++20 to allow optimizations for users providing wrapped iterator types.
446struct _LIBCPP_TEMPLATE_VIS contiguous_iterator_tag: public random_access_iterator_tag { };
447#endif
448
449template <class _Iter>
450struct __iter_traits_cache {
451  using type = _If<
452    __is_primary_template<iterator_traits<_Iter> >::value,
453    _Iter,
454    iterator_traits<_Iter>
455  >;
456};
457template <class _Iter>
458using _ITER_TRAITS = typename __iter_traits_cache<_Iter>::type;
459
460struct __iter_concept_concept_test {
461  template <class _Iter>
462  using _Apply = typename _ITER_TRAITS<_Iter>::iterator_concept;
463};
464struct __iter_concept_category_test {
465  template <class _Iter>
466  using _Apply = typename _ITER_TRAITS<_Iter>::iterator_category;
467};
468struct __iter_concept_random_fallback {
469  template <class _Iter>
470  using _Apply = _EnableIf<
471                          __is_primary_template<iterator_traits<_Iter> >::value,
472                          random_access_iterator_tag
473                        >;
474};
475
476template <class _Iter, class _Tester> struct __test_iter_concept
477    : _IsValidExpansion<_Tester::template _Apply, _Iter>,
478      _Tester
479{
480};
481
482template <class _Iter>
483struct __iter_concept_cache {
484  using type = _Or<
485    __test_iter_concept<_Iter, __iter_concept_concept_test>,
486    __test_iter_concept<_Iter, __iter_concept_category_test>,
487    __test_iter_concept<_Iter, __iter_concept_random_fallback>
488  >;
489};
490
491template <class _Iter>
492using _ITER_CONCEPT = typename __iter_concept_cache<_Iter>::type::template _Apply<_Iter>;
493
494
495template <class _Tp>
496struct __has_iterator_typedefs
497{
498private:
499    struct __two {char __lx; char __lxx;};
500    template <class _Up> static __two __test(...);
501    template <class _Up> static char __test(typename std::__void_t<typename _Up::iterator_category>::type* = 0,
502    										typename std::__void_t<typename _Up::difference_type>::type* = 0,
503    										typename std::__void_t<typename _Up::value_type>::type* = 0,
504    										typename std::__void_t<typename _Up::reference>::type* = 0,
505    										typename std::__void_t<typename _Up::pointer>::type* = 0
506    										);
507public:
508    static const bool value = sizeof(__test<_Tp>(0,0,0,0,0)) == 1;
509};
510
511
512template <class _Tp>
513struct __has_iterator_category
514{
515private:
516    struct __two {char __lx; char __lxx;};
517    template <class _Up> static __two __test(...);
518    template <class _Up> static char __test(typename _Up::iterator_category* = 0);
519public:
520    static const bool value = sizeof(__test<_Tp>(0)) == 1;
521};
522
523template <class _Iter, bool> struct __iterator_traits_impl {};
524
525template <class _Iter>
526struct __iterator_traits_impl<_Iter, true>
527{
528    typedef typename _Iter::difference_type   difference_type;
529    typedef typename _Iter::value_type        value_type;
530    typedef typename _Iter::pointer           pointer;
531    typedef typename _Iter::reference         reference;
532    typedef typename _Iter::iterator_category iterator_category;
533};
534
535template <class _Iter, bool> struct __iterator_traits {};
536
537template <class _Iter>
538struct __iterator_traits<_Iter, true>
539    :  __iterator_traits_impl
540      <
541        _Iter,
542        is_convertible<typename _Iter::iterator_category, input_iterator_tag>::value ||
543        is_convertible<typename _Iter::iterator_category, output_iterator_tag>::value
544      >
545{};
546
547// iterator_traits<Iterator> will only have the nested types if Iterator::iterator_category
548//    exists.  Else iterator_traits<Iterator> will be an empty class.  This is a
549//    conforming extension which allows some programs to compile and behave as
550//    the client expects instead of failing at compile time.
551
552template <class _Iter>
553struct _LIBCPP_TEMPLATE_VIS iterator_traits
554    : __iterator_traits<_Iter, __has_iterator_typedefs<_Iter>::value> {
555
556  using __primary_template = iterator_traits;
557};
558
559template<class _Tp>
560struct _LIBCPP_TEMPLATE_VIS iterator_traits<_Tp*>
561{
562    typedef ptrdiff_t difference_type;
563    typedef typename remove_cv<_Tp>::type value_type;
564    typedef _Tp* pointer;
565    typedef _Tp& reference;
566    typedef random_access_iterator_tag iterator_category;
567#if _LIBCPP_STD_VER > 17
568    typedef contiguous_iterator_tag    iterator_concept;
569#endif
570};
571
572template <class _Tp, class _Up, bool = __has_iterator_category<iterator_traits<_Tp> >::value>
573struct __has_iterator_category_convertible_to
574    : public integral_constant<bool, is_convertible<typename iterator_traits<_Tp>::iterator_category, _Up>::value>
575{};
576
577template <class _Tp, class _Up>
578struct __has_iterator_category_convertible_to<_Tp, _Up, false> : public false_type {};
579
580template <class _Tp>
581struct __is_cpp17_input_iterator : public __has_iterator_category_convertible_to<_Tp, input_iterator_tag> {};
582
583template <class _Tp>
584struct __is_cpp17_forward_iterator : public __has_iterator_category_convertible_to<_Tp, forward_iterator_tag> {};
585
586template <class _Tp>
587struct __is_cpp17_bidirectional_iterator : public __has_iterator_category_convertible_to<_Tp, bidirectional_iterator_tag> {};
588
589template <class _Tp>
590struct __is_cpp17_random_access_iterator : public __has_iterator_category_convertible_to<_Tp, random_access_iterator_tag> {};
591
592#if _LIBCPP_STD_VER > 17
593template <class _Tp>
594struct __is_cpp17_contiguous_iterator : public __has_iterator_category_convertible_to<_Tp, contiguous_iterator_tag> {};
595#else
596template <class _Tp>
597struct __is_cpp17_contiguous_iterator : public false_type {};
598#endif
599
600
601template <class _Tp>
602struct __is_exactly_cpp17_input_iterator
603    : public integral_constant<bool,
604         __has_iterator_category_convertible_to<_Tp, input_iterator_tag>::value &&
605        !__has_iterator_category_convertible_to<_Tp, forward_iterator_tag>::value> {};
606
607#ifndef _LIBCPP_HAS_NO_DEDUCTION_GUIDES
608template<class _InputIterator>
609using __iter_value_type = typename iterator_traits<_InputIterator>::value_type;
610
611template<class _InputIterator>
612using __iter_key_type = remove_const_t<typename iterator_traits<_InputIterator>::value_type::first_type>;
613
614template<class _InputIterator>
615using __iter_mapped_type = typename iterator_traits<_InputIterator>::value_type::second_type;
616
617template<class _InputIterator>
618using __iter_to_alloc_type = pair<
619    add_const_t<typename iterator_traits<_InputIterator>::value_type::first_type>,
620    typename iterator_traits<_InputIterator>::value_type::second_type>;
621#endif
622
623template<class _Category, class _Tp, class _Distance = ptrdiff_t,
624         class _Pointer = _Tp*, class _Reference = _Tp&>
625struct _LIBCPP_TEMPLATE_VIS iterator
626{
627    typedef _Tp        value_type;
628    typedef _Distance  difference_type;
629    typedef _Pointer   pointer;
630    typedef _Reference reference;
631    typedef _Category  iterator_category;
632};
633
634template <class _InputIter>
635inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
636void __advance(_InputIter& __i,
637             typename iterator_traits<_InputIter>::difference_type __n, input_iterator_tag)
638{
639    for (; __n > 0; --__n)
640        ++__i;
641}
642
643template <class _BiDirIter>
644inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
645void __advance(_BiDirIter& __i,
646             typename iterator_traits<_BiDirIter>::difference_type __n, bidirectional_iterator_tag)
647{
648    if (__n >= 0)
649        for (; __n > 0; --__n)
650            ++__i;
651    else
652        for (; __n < 0; ++__n)
653            --__i;
654}
655
656template <class _RandIter>
657inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
658void __advance(_RandIter& __i,
659             typename iterator_traits<_RandIter>::difference_type __n, random_access_iterator_tag)
660{
661   __i += __n;
662}
663
664template <class _InputIter, class _Distance>
665inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
666void advance(_InputIter& __i, _Distance __orig_n)
667{
668    _LIBCPP_ASSERT(__orig_n >= 0 || __is_cpp17_bidirectional_iterator<_InputIter>::value,
669                   "Attempt to advance(it, n) with negative n on a non-bidirectional iterator");
670    typedef decltype(__convert_to_integral(__orig_n)) _IntegralSize;
671    _IntegralSize __n = __orig_n;
672    __advance(__i, __n, typename iterator_traits<_InputIter>::iterator_category());
673}
674
675template <class _InputIter>
676inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
677typename iterator_traits<_InputIter>::difference_type
678__distance(_InputIter __first, _InputIter __last, input_iterator_tag)
679{
680    typename iterator_traits<_InputIter>::difference_type __r(0);
681    for (; __first != __last; ++__first)
682        ++__r;
683    return __r;
684}
685
686template <class _RandIter>
687inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
688typename iterator_traits<_RandIter>::difference_type
689__distance(_RandIter __first, _RandIter __last, random_access_iterator_tag)
690{
691    return __last - __first;
692}
693
694template <class _InputIter>
695inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
696typename iterator_traits<_InputIter>::difference_type
697distance(_InputIter __first, _InputIter __last)
698{
699    return __distance(__first, __last, typename iterator_traits<_InputIter>::iterator_category());
700}
701
702template <class _InputIter>
703inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
704typename enable_if
705<
706    __is_cpp17_input_iterator<_InputIter>::value,
707    _InputIter
708>::type
709next(_InputIter __x,
710     typename iterator_traits<_InputIter>::difference_type __n = 1)
711{
712    _LIBCPP_ASSERT(__n >= 0 || __is_cpp17_bidirectional_iterator<_InputIter>::value,
713                       "Attempt to next(it, n) with negative n on a non-bidirectional iterator");
714
715    _VSTD::advance(__x, __n);
716    return __x;
717}
718
719template <class _InputIter>
720inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
721typename enable_if
722<
723    __is_cpp17_input_iterator<_InputIter>::value,
724    _InputIter
725>::type
726prev(_InputIter __x,
727     typename iterator_traits<_InputIter>::difference_type __n = 1)
728{
729    _LIBCPP_ASSERT(__n <= 0 || __is_cpp17_bidirectional_iterator<_InputIter>::value,
730                       "Attempt to prev(it, n) with a positive n on a non-bidirectional iterator");
731    _VSTD::advance(__x, -__n);
732    return __x;
733}
734
735
736template <class _Tp, class = void>
737struct __is_stashing_iterator : false_type {};
738
739template <class _Tp>
740struct __is_stashing_iterator<_Tp, typename __void_t<typename _Tp::__stashing_iterator_tag>::type>
741  : true_type {};
742
743template <class _Iter>
744class _LIBCPP_TEMPLATE_VIS reverse_iterator
745    : public iterator<typename iterator_traits<_Iter>::iterator_category,
746                      typename iterator_traits<_Iter>::value_type,
747                      typename iterator_traits<_Iter>::difference_type,
748                      typename iterator_traits<_Iter>::pointer,
749                      typename iterator_traits<_Iter>::reference>
750{
751private:
752    /*mutable*/ _Iter __t;  // no longer used as of LWG #2360, not removed due to ABI break
753
754    static_assert(!__is_stashing_iterator<_Iter>::value,
755      "The specified iterator type cannot be used with reverse_iterator; "
756      "Using stashing iterators with reverse_iterator causes undefined behavior");
757
758protected:
759    _Iter current;
760public:
761    typedef _Iter                                            iterator_type;
762    typedef typename iterator_traits<_Iter>::difference_type difference_type;
763    typedef typename iterator_traits<_Iter>::reference       reference;
764    typedef typename iterator_traits<_Iter>::pointer         pointer;
765
766    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
767    reverse_iterator() : __t(), current() {}
768    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
769    explicit reverse_iterator(_Iter __x) : __t(__x), current(__x) {}
770    template <class _Up>
771        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
772        reverse_iterator(const reverse_iterator<_Up>& __u) : __t(__u.base()), current(__u.base()) {}
773    template <class _Up>
774        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
775        reverse_iterator& operator=(const reverse_iterator<_Up>& __u)
776            { __t = current = __u.base(); return *this; }
777    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
778    _Iter base() const {return current;}
779    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
780    reference operator*() const {_Iter __tmp = current; return *--__tmp;}
781    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
782    pointer  operator->() const {return _VSTD::addressof(operator*());}
783    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
784    reverse_iterator& operator++() {--current; return *this;}
785    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
786    reverse_iterator  operator++(int) {reverse_iterator __tmp(*this); --current; return __tmp;}
787    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
788    reverse_iterator& operator--() {++current; return *this;}
789    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
790    reverse_iterator  operator--(int) {reverse_iterator __tmp(*this); ++current; return __tmp;}
791    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
792    reverse_iterator  operator+ (difference_type __n) const {return reverse_iterator(current - __n);}
793    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
794    reverse_iterator& operator+=(difference_type __n) {current -= __n; return *this;}
795    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
796    reverse_iterator  operator- (difference_type __n) const {return reverse_iterator(current + __n);}
797    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
798    reverse_iterator& operator-=(difference_type __n) {current += __n; return *this;}
799    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
800    reference         operator[](difference_type __n) const {return *(*this + __n);}
801};
802
803template <class _Iter1, class _Iter2>
804inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
805bool
806operator==(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
807{
808    return __x.base() == __y.base();
809}
810
811template <class _Iter1, class _Iter2>
812inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
813bool
814operator<(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
815{
816    return __x.base() > __y.base();
817}
818
819template <class _Iter1, class _Iter2>
820inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
821bool
822operator!=(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
823{
824    return __x.base() != __y.base();
825}
826
827template <class _Iter1, class _Iter2>
828inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
829bool
830operator>(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
831{
832    return __x.base() < __y.base();
833}
834
835template <class _Iter1, class _Iter2>
836inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
837bool
838operator>=(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
839{
840    return __x.base() <= __y.base();
841}
842
843template <class _Iter1, class _Iter2>
844inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
845bool
846operator<=(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
847{
848    return __x.base() >= __y.base();
849}
850
851#ifndef _LIBCPP_CXX03_LANG
852template <class _Iter1, class _Iter2>
853inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
854auto
855operator-(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
856-> decltype(__y.base() - __x.base())
857{
858    return __y.base() - __x.base();
859}
860#else
861template <class _Iter1, class _Iter2>
862inline _LIBCPP_INLINE_VISIBILITY
863typename reverse_iterator<_Iter1>::difference_type
864operator-(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
865{
866    return __y.base() - __x.base();
867}
868#endif
869
870template <class _Iter>
871inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
872reverse_iterator<_Iter>
873operator+(typename reverse_iterator<_Iter>::difference_type __n, const reverse_iterator<_Iter>& __x)
874{
875    return reverse_iterator<_Iter>(__x.base() - __n);
876}
877
878#if _LIBCPP_STD_VER > 11
879template <class _Iter>
880inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
881reverse_iterator<_Iter> make_reverse_iterator(_Iter __i)
882{
883    return reverse_iterator<_Iter>(__i);
884}
885#endif
886
887template <class _Container>
888class _LIBCPP_TEMPLATE_VIS back_insert_iterator
889    : public iterator<output_iterator_tag,
890                      void,
891                      void,
892                      void,
893                      void>
894{
895protected:
896    _Container* container;
897public:
898    typedef _Container container_type;
899
900    _LIBCPP_INLINE_VISIBILITY explicit back_insert_iterator(_Container& __x) : container(_VSTD::addressof(__x)) {}
901    _LIBCPP_INLINE_VISIBILITY back_insert_iterator& operator=(const typename _Container::value_type& __value_)
902        {container->push_back(__value_); return *this;}
903#ifndef _LIBCPP_CXX03_LANG
904    _LIBCPP_INLINE_VISIBILITY back_insert_iterator& operator=(typename _Container::value_type&& __value_)
905        {container->push_back(_VSTD::move(__value_)); return *this;}
906#endif  // _LIBCPP_CXX03_LANG
907    _LIBCPP_INLINE_VISIBILITY back_insert_iterator& operator*()     {return *this;}
908    _LIBCPP_INLINE_VISIBILITY back_insert_iterator& operator++()    {return *this;}
909    _LIBCPP_INLINE_VISIBILITY back_insert_iterator  operator++(int) {return *this;}
910};
911
912template <class _Container>
913inline _LIBCPP_INLINE_VISIBILITY
914back_insert_iterator<_Container>
915back_inserter(_Container& __x)
916{
917    return back_insert_iterator<_Container>(__x);
918}
919
920template <class _Container>
921class _LIBCPP_TEMPLATE_VIS front_insert_iterator
922    : public iterator<output_iterator_tag,
923                      void,
924                      void,
925                      void,
926                      void>
927{
928protected:
929    _Container* container;
930public:
931    typedef _Container container_type;
932
933    _LIBCPP_INLINE_VISIBILITY explicit front_insert_iterator(_Container& __x) : container(_VSTD::addressof(__x)) {}
934    _LIBCPP_INLINE_VISIBILITY front_insert_iterator& operator=(const typename _Container::value_type& __value_)
935        {container->push_front(__value_); return *this;}
936#ifndef _LIBCPP_CXX03_LANG
937    _LIBCPP_INLINE_VISIBILITY front_insert_iterator& operator=(typename _Container::value_type&& __value_)
938        {container->push_front(_VSTD::move(__value_)); return *this;}
939#endif  // _LIBCPP_CXX03_LANG
940    _LIBCPP_INLINE_VISIBILITY front_insert_iterator& operator*()     {return *this;}
941    _LIBCPP_INLINE_VISIBILITY front_insert_iterator& operator++()    {return *this;}
942    _LIBCPP_INLINE_VISIBILITY front_insert_iterator  operator++(int) {return *this;}
943};
944
945template <class _Container>
946inline _LIBCPP_INLINE_VISIBILITY
947front_insert_iterator<_Container>
948front_inserter(_Container& __x)
949{
950    return front_insert_iterator<_Container>(__x);
951}
952
953template <class _Container>
954class _LIBCPP_TEMPLATE_VIS insert_iterator
955    : public iterator<output_iterator_tag,
956                      void,
957                      void,
958                      void,
959                      void>
960{
961protected:
962    _Container* container;
963    typename _Container::iterator iter;
964public:
965    typedef _Container container_type;
966
967    _LIBCPP_INLINE_VISIBILITY insert_iterator(_Container& __x, typename _Container::iterator __i)
968        : container(_VSTD::addressof(__x)), iter(__i) {}
969    _LIBCPP_INLINE_VISIBILITY insert_iterator& operator=(const typename _Container::value_type& __value_)
970        {iter = container->insert(iter, __value_); ++iter; return *this;}
971#ifndef _LIBCPP_CXX03_LANG
972    _LIBCPP_INLINE_VISIBILITY insert_iterator& operator=(typename _Container::value_type&& __value_)
973        {iter = container->insert(iter, _VSTD::move(__value_)); ++iter; return *this;}
974#endif  // _LIBCPP_CXX03_LANG
975    _LIBCPP_INLINE_VISIBILITY insert_iterator& operator*()        {return *this;}
976    _LIBCPP_INLINE_VISIBILITY insert_iterator& operator++()       {return *this;}
977    _LIBCPP_INLINE_VISIBILITY insert_iterator& operator++(int)    {return *this;}
978};
979
980template <class _Container>
981inline _LIBCPP_INLINE_VISIBILITY
982insert_iterator<_Container>
983inserter(_Container& __x, typename _Container::iterator __i)
984{
985    return insert_iterator<_Container>(__x, __i);
986}
987
988template <class _Tp, class _CharT = char,
989          class _Traits = char_traits<_CharT>, class _Distance = ptrdiff_t>
990class _LIBCPP_TEMPLATE_VIS istream_iterator
991    : public iterator<input_iterator_tag, _Tp, _Distance, const _Tp*, const _Tp&>
992{
993public:
994    typedef _CharT char_type;
995    typedef _Traits traits_type;
996    typedef basic_istream<_CharT,_Traits> istream_type;
997private:
998    istream_type* __in_stream_;
999    _Tp __value_;
1000public:
1001    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR istream_iterator() : __in_stream_(0), __value_() {}
1002    _LIBCPP_INLINE_VISIBILITY istream_iterator(istream_type& __s) : __in_stream_(_VSTD::addressof(__s))
1003        {
1004            if (!(*__in_stream_ >> __value_))
1005                __in_stream_ = 0;
1006        }
1007
1008    _LIBCPP_INLINE_VISIBILITY const _Tp& operator*() const {return __value_;}
1009    _LIBCPP_INLINE_VISIBILITY const _Tp* operator->() const {return _VSTD::addressof((operator*()));}
1010    _LIBCPP_INLINE_VISIBILITY istream_iterator& operator++()
1011        {
1012            if (!(*__in_stream_ >> __value_))
1013                __in_stream_ = 0;
1014            return *this;
1015        }
1016    _LIBCPP_INLINE_VISIBILITY istream_iterator  operator++(int)
1017        {istream_iterator __t(*this); ++(*this); return __t;}
1018
1019    template <class _Up, class _CharU, class _TraitsU, class _DistanceU>
1020    friend _LIBCPP_INLINE_VISIBILITY
1021    bool
1022    operator==(const istream_iterator<_Up, _CharU, _TraitsU, _DistanceU>& __x,
1023               const istream_iterator<_Up, _CharU, _TraitsU, _DistanceU>& __y);
1024
1025    template <class _Up, class _CharU, class _TraitsU, class _DistanceU>
1026    friend _LIBCPP_INLINE_VISIBILITY
1027    bool
1028    operator==(const istream_iterator<_Up, _CharU, _TraitsU, _DistanceU>& __x,
1029               const istream_iterator<_Up, _CharU, _TraitsU, _DistanceU>& __y);
1030};
1031
1032template <class _Tp, class _CharT, class _Traits, class _Distance>
1033inline _LIBCPP_INLINE_VISIBILITY
1034bool
1035operator==(const istream_iterator<_Tp, _CharT, _Traits, _Distance>& __x,
1036           const istream_iterator<_Tp, _CharT, _Traits, _Distance>& __y)
1037{
1038    return __x.__in_stream_ == __y.__in_stream_;
1039}
1040
1041template <class _Tp, class _CharT, class _Traits, class _Distance>
1042inline _LIBCPP_INLINE_VISIBILITY
1043bool
1044operator!=(const istream_iterator<_Tp, _CharT, _Traits, _Distance>& __x,
1045           const istream_iterator<_Tp, _CharT, _Traits, _Distance>& __y)
1046{
1047    return !(__x == __y);
1048}
1049
1050template <class _Tp, class _CharT = char, class _Traits = char_traits<_CharT> >
1051class _LIBCPP_TEMPLATE_VIS ostream_iterator
1052    : public iterator<output_iterator_tag, void, void, void, void>
1053{
1054public:
1055    typedef _CharT char_type;
1056    typedef _Traits traits_type;
1057    typedef basic_ostream<_CharT,_Traits> ostream_type;
1058private:
1059    ostream_type* __out_stream_;
1060    const char_type* __delim_;
1061public:
1062    _LIBCPP_INLINE_VISIBILITY ostream_iterator(ostream_type& __s) _NOEXCEPT
1063        : __out_stream_(_VSTD::addressof(__s)), __delim_(0) {}
1064    _LIBCPP_INLINE_VISIBILITY ostream_iterator(ostream_type& __s, const _CharT* __delimiter) _NOEXCEPT
1065        : __out_stream_(_VSTD::addressof(__s)), __delim_(__delimiter) {}
1066    _LIBCPP_INLINE_VISIBILITY ostream_iterator& operator=(const _Tp& __value_)
1067        {
1068            *__out_stream_ << __value_;
1069            if (__delim_)
1070                *__out_stream_ << __delim_;
1071            return *this;
1072        }
1073
1074    _LIBCPP_INLINE_VISIBILITY ostream_iterator& operator*()     {return *this;}
1075    _LIBCPP_INLINE_VISIBILITY ostream_iterator& operator++()    {return *this;}
1076    _LIBCPP_INLINE_VISIBILITY ostream_iterator& operator++(int) {return *this;}
1077};
1078
1079template<class _CharT, class _Traits>
1080class _LIBCPP_TEMPLATE_VIS istreambuf_iterator
1081    : public iterator<input_iterator_tag, _CharT,
1082                      typename _Traits::off_type, _CharT*,
1083                      _CharT>
1084{
1085public:
1086    typedef _CharT                          char_type;
1087    typedef _Traits                         traits_type;
1088    typedef typename _Traits::int_type      int_type;
1089    typedef basic_streambuf<_CharT,_Traits> streambuf_type;
1090    typedef basic_istream<_CharT,_Traits>   istream_type;
1091private:
1092    mutable streambuf_type* __sbuf_;
1093
1094    class __proxy
1095    {
1096        char_type __keep_;
1097        streambuf_type* __sbuf_;
1098        _LIBCPP_INLINE_VISIBILITY __proxy(char_type __c, streambuf_type* __s)
1099            : __keep_(__c), __sbuf_(__s) {}
1100        friend class istreambuf_iterator;
1101    public:
1102        _LIBCPP_INLINE_VISIBILITY char_type operator*() const {return __keep_;}
1103    };
1104
1105    _LIBCPP_INLINE_VISIBILITY
1106    bool __test_for_eof() const
1107    {
1108        if (__sbuf_ && traits_type::eq_int_type(__sbuf_->sgetc(), traits_type::eof()))
1109            __sbuf_ = 0;
1110        return __sbuf_ == 0;
1111    }
1112public:
1113    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR istreambuf_iterator() _NOEXCEPT : __sbuf_(0) {}
1114    _LIBCPP_INLINE_VISIBILITY istreambuf_iterator(istream_type& __s) _NOEXCEPT
1115        : __sbuf_(__s.rdbuf()) {}
1116    _LIBCPP_INLINE_VISIBILITY istreambuf_iterator(streambuf_type* __s) _NOEXCEPT
1117        : __sbuf_(__s) {}
1118    _LIBCPP_INLINE_VISIBILITY istreambuf_iterator(const __proxy& __p) _NOEXCEPT
1119        : __sbuf_(__p.__sbuf_) {}
1120
1121    _LIBCPP_INLINE_VISIBILITY char_type  operator*() const
1122        {return static_cast<char_type>(__sbuf_->sgetc());}
1123    _LIBCPP_INLINE_VISIBILITY istreambuf_iterator& operator++()
1124        {
1125            __sbuf_->sbumpc();
1126            return *this;
1127        }
1128    _LIBCPP_INLINE_VISIBILITY __proxy              operator++(int)
1129        {
1130            return __proxy(__sbuf_->sbumpc(), __sbuf_);
1131        }
1132
1133    _LIBCPP_INLINE_VISIBILITY bool equal(const istreambuf_iterator& __b) const
1134        {return __test_for_eof() == __b.__test_for_eof();}
1135};
1136
1137template <class _CharT, class _Traits>
1138inline _LIBCPP_INLINE_VISIBILITY
1139bool operator==(const istreambuf_iterator<_CharT,_Traits>& __a,
1140                const istreambuf_iterator<_CharT,_Traits>& __b)
1141                {return __a.equal(__b);}
1142
1143template <class _CharT, class _Traits>
1144inline _LIBCPP_INLINE_VISIBILITY
1145bool operator!=(const istreambuf_iterator<_CharT,_Traits>& __a,
1146                const istreambuf_iterator<_CharT,_Traits>& __b)
1147                {return !__a.equal(__b);}
1148
1149template <class _CharT, class _Traits>
1150class _LIBCPP_TEMPLATE_VIS ostreambuf_iterator
1151    : public iterator<output_iterator_tag, void, void, void, void>
1152{
1153public:
1154    typedef _CharT                          char_type;
1155    typedef _Traits                         traits_type;
1156    typedef basic_streambuf<_CharT,_Traits> streambuf_type;
1157    typedef basic_ostream<_CharT,_Traits>   ostream_type;
1158private:
1159    streambuf_type* __sbuf_;
1160public:
1161    _LIBCPP_INLINE_VISIBILITY ostreambuf_iterator(ostream_type& __s) _NOEXCEPT
1162        : __sbuf_(__s.rdbuf()) {}
1163    _LIBCPP_INLINE_VISIBILITY ostreambuf_iterator(streambuf_type* __s) _NOEXCEPT
1164        : __sbuf_(__s) {}
1165    _LIBCPP_INLINE_VISIBILITY ostreambuf_iterator& operator=(_CharT __c)
1166        {
1167            if (__sbuf_ && traits_type::eq_int_type(__sbuf_->sputc(__c), traits_type::eof()))
1168                __sbuf_ = 0;
1169            return *this;
1170        }
1171    _LIBCPP_INLINE_VISIBILITY ostreambuf_iterator& operator*()     {return *this;}
1172    _LIBCPP_INLINE_VISIBILITY ostreambuf_iterator& operator++()    {return *this;}
1173    _LIBCPP_INLINE_VISIBILITY ostreambuf_iterator& operator++(int) {return *this;}
1174    _LIBCPP_INLINE_VISIBILITY bool failed() const _NOEXCEPT {return __sbuf_ == 0;}
1175
1176    template <class _Ch, class _Tr>
1177    friend
1178    _LIBCPP_HIDDEN
1179    ostreambuf_iterator<_Ch, _Tr>
1180    __pad_and_output(ostreambuf_iterator<_Ch, _Tr> __s,
1181                     const _Ch* __ob, const _Ch* __op, const _Ch* __oe,
1182                     ios_base& __iob, _Ch __fl);
1183};
1184
1185template <class _Iter>
1186class _LIBCPP_TEMPLATE_VIS move_iterator
1187{
1188private:
1189    _Iter __i;
1190public:
1191    typedef _Iter                                            iterator_type;
1192    typedef typename iterator_traits<iterator_type>::iterator_category iterator_category;
1193    typedef typename iterator_traits<iterator_type>::value_type value_type;
1194    typedef typename iterator_traits<iterator_type>::difference_type difference_type;
1195    typedef iterator_type pointer;
1196#ifndef _LIBCPP_CXX03_LANG
1197    typedef typename iterator_traits<iterator_type>::reference __reference;
1198    typedef typename conditional<
1199            is_reference<__reference>::value,
1200            typename remove_reference<__reference>::type&&,
1201            __reference
1202        >::type reference;
1203#else
1204    typedef typename iterator_traits<iterator_type>::reference reference;
1205#endif
1206
1207    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1208    move_iterator() : __i() {}
1209    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1210    explicit move_iterator(_Iter __x) : __i(__x) {}
1211    template <class _Up>
1212      _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1213      move_iterator(const move_iterator<_Up>& __u) : __i(__u.base()) {}
1214    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 _Iter base() const {return __i;}
1215    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1216    reference operator*() const { return static_cast<reference>(*__i); }
1217    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1218    pointer  operator->() const { return __i;}
1219    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1220    move_iterator& operator++() {++__i; return *this;}
1221    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1222    move_iterator  operator++(int) {move_iterator __tmp(*this); ++__i; return __tmp;}
1223    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1224    move_iterator& operator--() {--__i; return *this;}
1225    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1226    move_iterator  operator--(int) {move_iterator __tmp(*this); --__i; return __tmp;}
1227    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1228    move_iterator  operator+ (difference_type __n) const {return move_iterator(__i + __n);}
1229    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1230    move_iterator& operator+=(difference_type __n) {__i += __n; return *this;}
1231    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1232    move_iterator  operator- (difference_type __n) const {return move_iterator(__i - __n);}
1233    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1234    move_iterator& operator-=(difference_type __n) {__i -= __n; return *this;}
1235    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1236    reference operator[](difference_type __n) const { return static_cast<reference>(__i[__n]); }
1237};
1238
1239template <class _Iter1, class _Iter2>
1240inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1241bool
1242operator==(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
1243{
1244    return __x.base() == __y.base();
1245}
1246
1247template <class _Iter1, class _Iter2>
1248inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1249bool
1250operator<(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
1251{
1252    return __x.base() < __y.base();
1253}
1254
1255template <class _Iter1, class _Iter2>
1256inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1257bool
1258operator!=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
1259{
1260    return __x.base() != __y.base();
1261}
1262
1263template <class _Iter1, class _Iter2>
1264inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1265bool
1266operator>(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
1267{
1268    return __x.base() > __y.base();
1269}
1270
1271template <class _Iter1, class _Iter2>
1272inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1273bool
1274operator>=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
1275{
1276    return __x.base() >= __y.base();
1277}
1278
1279template <class _Iter1, class _Iter2>
1280inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1281bool
1282operator<=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
1283{
1284    return __x.base() <= __y.base();
1285}
1286
1287#ifndef _LIBCPP_CXX03_LANG
1288template <class _Iter1, class _Iter2>
1289inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1290auto
1291operator-(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
1292-> decltype(__x.base() - __y.base())
1293{
1294    return __x.base() - __y.base();
1295}
1296#else
1297template <class _Iter1, class _Iter2>
1298inline _LIBCPP_INLINE_VISIBILITY
1299typename move_iterator<_Iter1>::difference_type
1300operator-(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
1301{
1302    return __x.base() - __y.base();
1303}
1304#endif
1305
1306template <class _Iter>
1307inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1308move_iterator<_Iter>
1309operator+(typename move_iterator<_Iter>::difference_type __n, const move_iterator<_Iter>& __x)
1310{
1311    return move_iterator<_Iter>(__x.base() + __n);
1312}
1313
1314template <class _Iter>
1315inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1316move_iterator<_Iter>
1317make_move_iterator(_Iter __i)
1318{
1319    return move_iterator<_Iter>(__i);
1320}
1321
1322// __wrap_iter
1323
1324template <class _Iter> class __wrap_iter;
1325
1326template <class _Iter1, class _Iter2>
1327_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1328bool
1329operator==(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT;
1330
1331template <class _Iter1, class _Iter2>
1332_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1333bool
1334operator<(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT;
1335
1336template <class _Iter1, class _Iter2>
1337_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1338bool
1339operator!=(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT;
1340
1341template <class _Iter1, class _Iter2>
1342_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1343bool
1344operator>(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT;
1345
1346template <class _Iter1, class _Iter2>
1347_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1348bool
1349operator>=(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT;
1350
1351template <class _Iter1, class _Iter2>
1352_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1353bool
1354operator<=(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT;
1355
1356#ifndef _LIBCPP_CXX03_LANG
1357template <class _Iter1, class _Iter2>
1358_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1359auto
1360operator-(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT
1361-> decltype(__x.base() - __y.base());
1362#else
1363template <class _Iter1, class _Iter2>
1364_LIBCPP_INLINE_VISIBILITY
1365typename __wrap_iter<_Iter1>::difference_type
1366operator-(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT;
1367#endif
1368
1369template <class _Iter>
1370_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1371__wrap_iter<_Iter>
1372operator+(typename __wrap_iter<_Iter>::difference_type, __wrap_iter<_Iter>) _NOEXCEPT;
1373
1374template <class _Ip, class _Op> _Op _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 copy(_Ip, _Ip, _Op);
1375template <class _B1, class _B2> _B2 _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 copy_backward(_B1, _B1, _B2);
1376template <class _Ip, class _Op> _Op _LIBCPP_INLINE_VISIBILITY move(_Ip, _Ip, _Op);
1377template <class _B1, class _B2> _B2 _LIBCPP_INLINE_VISIBILITY move_backward(_B1, _B1, _B2);
1378
1379#if _LIBCPP_DEBUG_LEVEL < 2
1380
1381template <class _Tp>
1382_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1383typename enable_if
1384<
1385    is_trivially_copy_assignable<_Tp>::value,
1386    _Tp*
1387>::type
1388__unwrap_iter(__wrap_iter<_Tp*>);
1389
1390#else
1391
1392template <class _Tp>
1393inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1394typename enable_if
1395<
1396    is_trivially_copy_assignable<_Tp>::value,
1397    __wrap_iter<_Tp*>
1398>::type
1399__unwrap_iter(__wrap_iter<_Tp*> __i);
1400
1401#endif
1402
1403template <class _Iter>
1404class __wrap_iter
1405{
1406public:
1407    typedef _Iter                                                      iterator_type;
1408    typedef typename iterator_traits<iterator_type>::iterator_category iterator_category;
1409    typedef typename iterator_traits<iterator_type>::value_type        value_type;
1410    typedef typename iterator_traits<iterator_type>::difference_type   difference_type;
1411    typedef typename iterator_traits<iterator_type>::pointer           pointer;
1412    typedef typename iterator_traits<iterator_type>::reference         reference;
1413private:
1414    iterator_type __i;
1415public:
1416    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG __wrap_iter() _NOEXCEPT
1417#if _LIBCPP_STD_VER > 11
1418                : __i{}
1419#endif
1420    {
1421#if _LIBCPP_DEBUG_LEVEL >= 2
1422        __get_db()->__insert_i(this);
1423#endif
1424    }
1425    template <class _Up> _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1426        __wrap_iter(const __wrap_iter<_Up>& __u,
1427            typename enable_if<is_convertible<_Up, iterator_type>::value>::type* = 0) _NOEXCEPT
1428            : __i(__u.base())
1429    {
1430#if _LIBCPP_DEBUG_LEVEL >= 2
1431        __get_db()->__iterator_copy(this, &__u);
1432#endif
1433    }
1434#if _LIBCPP_DEBUG_LEVEL >= 2
1435    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1436    __wrap_iter(const __wrap_iter& __x)
1437        : __i(__x.base())
1438    {
1439        __get_db()->__iterator_copy(this, &__x);
1440    }
1441    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1442    __wrap_iter& operator=(const __wrap_iter& __x)
1443    {
1444        if (this != &__x)
1445        {
1446            __get_db()->__iterator_copy(this, &__x);
1447            __i = __x.__i;
1448        }
1449        return *this;
1450    }
1451    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1452    ~__wrap_iter()
1453    {
1454        __get_db()->__erase_i(this);
1455    }
1456#endif
1457    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG reference operator*() const _NOEXCEPT
1458    {
1459#if _LIBCPP_DEBUG_LEVEL >= 2
1460        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
1461                       "Attempted to dereference a non-dereferenceable iterator");
1462#endif
1463        return *__i;
1464    }
1465    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG pointer  operator->() const _NOEXCEPT
1466    {
1467#if _LIBCPP_DEBUG_LEVEL >= 2
1468        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
1469                       "Attempted to dereference a non-dereferenceable iterator");
1470#endif
1471        return (pointer)_VSTD::addressof(*__i);
1472    }
1473    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG __wrap_iter& operator++() _NOEXCEPT
1474    {
1475#if _LIBCPP_DEBUG_LEVEL >= 2
1476        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
1477                       "Attempted to increment non-incrementable iterator");
1478#endif
1479        ++__i;
1480        return *this;
1481    }
1482    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG __wrap_iter  operator++(int) _NOEXCEPT
1483        {__wrap_iter __tmp(*this); ++(*this); return __tmp;}
1484
1485    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG __wrap_iter& operator--() _NOEXCEPT
1486    {
1487#if _LIBCPP_DEBUG_LEVEL >= 2
1488        _LIBCPP_ASSERT(__get_const_db()->__decrementable(this),
1489                       "Attempted to decrement non-decrementable iterator");
1490#endif
1491        --__i;
1492        return *this;
1493    }
1494    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG __wrap_iter  operator--(int) _NOEXCEPT
1495        {__wrap_iter __tmp(*this); --(*this); return __tmp;}
1496    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG __wrap_iter  operator+ (difference_type __n) const _NOEXCEPT
1497        {__wrap_iter __w(*this); __w += __n; return __w;}
1498    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG __wrap_iter& operator+=(difference_type __n) _NOEXCEPT
1499    {
1500#if _LIBCPP_DEBUG_LEVEL >= 2
1501        _LIBCPP_ASSERT(__get_const_db()->__addable(this, __n),
1502                   "Attempted to add/subtract iterator outside of valid range");
1503#endif
1504        __i += __n;
1505        return *this;
1506    }
1507    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG __wrap_iter  operator- (difference_type __n) const _NOEXCEPT
1508        {return *this + (-__n);}
1509    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG __wrap_iter& operator-=(difference_type __n) _NOEXCEPT
1510        {*this += -__n; return *this;}
1511    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG reference    operator[](difference_type __n) const _NOEXCEPT
1512    {
1513#if _LIBCPP_DEBUG_LEVEL >= 2
1514        _LIBCPP_ASSERT(__get_const_db()->__subscriptable(this, __n),
1515                   "Attempted to subscript iterator outside of valid range");
1516#endif
1517        return __i[__n];
1518    }
1519
1520    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG iterator_type base() const _NOEXCEPT {return __i;}
1521
1522private:
1523#if _LIBCPP_DEBUG_LEVEL >= 2
1524    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG __wrap_iter(const void* __p, iterator_type __x) : __i(__x)
1525    {
1526        __get_db()->__insert_ic(this, __p);
1527    }
1528#else
1529    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG __wrap_iter(iterator_type __x) _NOEXCEPT : __i(__x) {}
1530#endif
1531
1532    template <class _Up> friend class __wrap_iter;
1533    template <class _CharT, class _Traits, class _Alloc> friend class basic_string;
1534    template <class _Tp, class _Alloc> friend class _LIBCPP_TEMPLATE_VIS vector;
1535    template <class _Tp, size_t> friend class _LIBCPP_TEMPLATE_VIS span;
1536
1537    template <class _Iter1, class _Iter2>
1538    _LIBCPP_CONSTEXPR_IF_NODEBUG friend
1539    bool
1540    operator==(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT;
1541
1542    template <class _Iter1, class _Iter2>
1543    _LIBCPP_CONSTEXPR_IF_NODEBUG friend
1544    bool
1545    operator<(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT;
1546
1547    template <class _Iter1, class _Iter2>
1548    _LIBCPP_CONSTEXPR_IF_NODEBUG friend
1549    bool
1550    operator!=(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT;
1551
1552    template <class _Iter1, class _Iter2>
1553    _LIBCPP_CONSTEXPR_IF_NODEBUG friend
1554    bool
1555    operator>(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT;
1556
1557    template <class _Iter1, class _Iter2>
1558    _LIBCPP_CONSTEXPR_IF_NODEBUG friend
1559    bool
1560    operator>=(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT;
1561
1562    template <class _Iter1, class _Iter2>
1563    _LIBCPP_CONSTEXPR_IF_NODEBUG friend
1564    bool
1565    operator<=(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT;
1566
1567#ifndef _LIBCPP_CXX03_LANG
1568    template <class _Iter1, class _Iter2>
1569    _LIBCPP_CONSTEXPR_IF_NODEBUG friend
1570    auto
1571    operator-(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT
1572    -> decltype(__x.base() - __y.base());
1573#else
1574    template <class _Iter1, class _Iter2>
1575    _LIBCPP_CONSTEXPR_IF_NODEBUG friend
1576    typename __wrap_iter<_Iter1>::difference_type
1577    operator-(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT;
1578#endif
1579
1580    template <class _Iter1>
1581    _LIBCPP_CONSTEXPR_IF_NODEBUG friend
1582    __wrap_iter<_Iter1>
1583    operator+(typename __wrap_iter<_Iter1>::difference_type, __wrap_iter<_Iter1>) _NOEXCEPT;
1584
1585    template <class _Ip, class _Op> friend _LIBCPP_CONSTEXPR_AFTER_CXX17 _Op copy(_Ip, _Ip, _Op);
1586    template <class _B1, class _B2> friend _LIBCPP_CONSTEXPR_AFTER_CXX17 _B2 copy_backward(_B1, _B1, _B2);
1587    template <class _Ip, class _Op> friend _Op move(_Ip, _Ip, _Op);
1588    template <class _B1, class _B2> friend _B2 move_backward(_B1, _B1, _B2);
1589
1590#if _LIBCPP_DEBUG_LEVEL < 2
1591    template <class _Tp>
1592    _LIBCPP_CONSTEXPR_IF_NODEBUG friend
1593    typename enable_if
1594    <
1595        is_trivially_copy_assignable<_Tp>::value,
1596        _Tp*
1597    >::type
1598    __unwrap_iter(__wrap_iter<_Tp*>);
1599#else
1600  template <class _Tp>
1601  inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1602  typename enable_if
1603  <
1604      is_trivially_copy_assignable<_Tp>::value,
1605      __wrap_iter<_Tp*>
1606  >::type
1607  __unwrap_iter(__wrap_iter<_Tp*> __i);
1608#endif
1609};
1610
1611template <class _Iter1, class _Iter2>
1612inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1613bool
1614operator==(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT
1615{
1616    return __x.base() == __y.base();
1617}
1618
1619template <class _Iter1, class _Iter2>
1620inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1621bool
1622operator<(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT
1623{
1624#if _LIBCPP_DEBUG_LEVEL >= 2
1625    _LIBCPP_ASSERT(__get_const_db()->__less_than_comparable(&__x, &__y),
1626                   "Attempted to compare incomparable iterators");
1627#endif
1628    return __x.base() < __y.base();
1629}
1630
1631template <class _Iter1, class _Iter2>
1632inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1633bool
1634operator!=(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT
1635{
1636    return !(__x == __y);
1637}
1638
1639template <class _Iter1, class _Iter2>
1640inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1641bool
1642operator>(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT
1643{
1644    return __y < __x;
1645}
1646
1647template <class _Iter1, class _Iter2>
1648inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1649bool
1650operator>=(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT
1651{
1652    return !(__x < __y);
1653}
1654
1655template <class _Iter1, class _Iter2>
1656inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1657bool
1658operator<=(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT
1659{
1660    return !(__y < __x);
1661}
1662
1663template <class _Iter1>
1664inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1665bool
1666operator!=(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter1>& __y) _NOEXCEPT
1667{
1668    return !(__x == __y);
1669}
1670
1671template <class _Iter1>
1672inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1673bool
1674operator>(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter1>& __y) _NOEXCEPT
1675{
1676    return __y < __x;
1677}
1678
1679template <class _Iter1>
1680inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1681bool
1682operator>=(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter1>& __y) _NOEXCEPT
1683{
1684    return !(__x < __y);
1685}
1686
1687template <class _Iter1>
1688inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1689bool
1690operator<=(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter1>& __y) _NOEXCEPT
1691{
1692    return !(__y < __x);
1693}
1694
1695#ifndef _LIBCPP_CXX03_LANG
1696template <class _Iter1, class _Iter2>
1697inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1698auto
1699operator-(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT
1700-> decltype(__x.base() - __y.base())
1701{
1702#if _LIBCPP_DEBUG_LEVEL >= 2
1703    _LIBCPP_ASSERT(__get_const_db()->__less_than_comparable(&__x, &__y),
1704                   "Attempted to subtract incompatible iterators");
1705#endif
1706    return __x.base() - __y.base();
1707}
1708#else
1709template <class _Iter1, class _Iter2>
1710inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1711typename __wrap_iter<_Iter1>::difference_type
1712operator-(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT
1713{
1714#if _LIBCPP_DEBUG_LEVEL >= 2
1715    _LIBCPP_ASSERT(__get_const_db()->__less_than_comparable(&__x, &__y),
1716                   "Attempted to subtract incompatible iterators");
1717#endif
1718    return __x.base() - __y.base();
1719}
1720#endif
1721
1722template <class _Iter>
1723inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_IF_NODEBUG
1724__wrap_iter<_Iter>
1725operator+(typename __wrap_iter<_Iter>::difference_type __n,
1726          __wrap_iter<_Iter> __x) _NOEXCEPT
1727{
1728    __x += __n;
1729    return __x;
1730}
1731
1732template <class _Iter>
1733struct __libcpp_is_trivial_iterator
1734    : public _LIBCPP_BOOL_CONSTANT(is_pointer<_Iter>::value) {};
1735
1736template <class _Iter>
1737struct __libcpp_is_trivial_iterator<move_iterator<_Iter> >
1738    : public _LIBCPP_BOOL_CONSTANT(__libcpp_is_trivial_iterator<_Iter>::value) {};
1739
1740template <class _Iter>
1741struct __libcpp_is_trivial_iterator<reverse_iterator<_Iter> >
1742    : public _LIBCPP_BOOL_CONSTANT(__libcpp_is_trivial_iterator<_Iter>::value) {};
1743
1744template <class _Iter>
1745struct __libcpp_is_trivial_iterator<__wrap_iter<_Iter> >
1746    : public _LIBCPP_BOOL_CONSTANT(__libcpp_is_trivial_iterator<_Iter>::value) {};
1747
1748
1749template <class _Tp, size_t _Np>
1750_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1751_Tp*
1752begin(_Tp (&__array)[_Np])
1753{
1754    return __array;
1755}
1756
1757template <class _Tp, size_t _Np>
1758_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1759_Tp*
1760end(_Tp (&__array)[_Np])
1761{
1762    return __array + _Np;
1763}
1764
1765#if !defined(_LIBCPP_CXX03_LANG)
1766
1767template <class _Cp>
1768_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1769auto
1770begin(_Cp& __c) -> decltype(__c.begin())
1771{
1772    return __c.begin();
1773}
1774
1775template <class _Cp>
1776_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1777auto
1778begin(const _Cp& __c) -> decltype(__c.begin())
1779{
1780    return __c.begin();
1781}
1782
1783template <class _Cp>
1784_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1785auto
1786end(_Cp& __c) -> decltype(__c.end())
1787{
1788    return __c.end();
1789}
1790
1791template <class _Cp>
1792_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1793auto
1794end(const _Cp& __c) -> decltype(__c.end())
1795{
1796    return __c.end();
1797}
1798
1799#if _LIBCPP_STD_VER > 11
1800
1801template <class _Tp, size_t _Np>
1802_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1803reverse_iterator<_Tp*> rbegin(_Tp (&__array)[_Np])
1804{
1805    return reverse_iterator<_Tp*>(__array + _Np);
1806}
1807
1808template <class _Tp, size_t _Np>
1809_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1810reverse_iterator<_Tp*> rend(_Tp (&__array)[_Np])
1811{
1812    return reverse_iterator<_Tp*>(__array);
1813}
1814
1815template <class _Ep>
1816_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1817reverse_iterator<const _Ep*> rbegin(initializer_list<_Ep> __il)
1818{
1819    return reverse_iterator<const _Ep*>(__il.end());
1820}
1821
1822template <class _Ep>
1823_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1824reverse_iterator<const _Ep*> rend(initializer_list<_Ep> __il)
1825{
1826    return reverse_iterator<const _Ep*>(__il.begin());
1827}
1828
1829template <class _Cp>
1830_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1831auto cbegin(const _Cp& __c) -> decltype(_VSTD::begin(__c))
1832{
1833    return _VSTD::begin(__c);
1834}
1835
1836template <class _Cp>
1837_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1838auto cend(const _Cp& __c) -> decltype(_VSTD::end(__c))
1839{
1840    return _VSTD::end(__c);
1841}
1842
1843template <class _Cp>
1844_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1845auto rbegin(_Cp& __c) -> decltype(__c.rbegin())
1846{
1847    return __c.rbegin();
1848}
1849
1850template <class _Cp>
1851_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1852auto rbegin(const _Cp& __c) -> decltype(__c.rbegin())
1853{
1854    return __c.rbegin();
1855}
1856
1857template <class _Cp>
1858_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1859auto rend(_Cp& __c) -> decltype(__c.rend())
1860{
1861    return __c.rend();
1862}
1863
1864template <class _Cp>
1865_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1866auto rend(const _Cp& __c) -> decltype(__c.rend())
1867{
1868    return __c.rend();
1869}
1870
1871template <class _Cp>
1872_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1873auto crbegin(const _Cp& __c) -> decltype(_VSTD::rbegin(__c))
1874{
1875    return _VSTD::rbegin(__c);
1876}
1877
1878template <class _Cp>
1879_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1880auto crend(const _Cp& __c) -> decltype(_VSTD::rend(__c))
1881{
1882    return _VSTD::rend(__c);
1883}
1884
1885#endif
1886
1887
1888#else  // defined(_LIBCPP_CXX03_LANG)
1889
1890template <class _Cp>
1891_LIBCPP_INLINE_VISIBILITY
1892typename _Cp::iterator
1893begin(_Cp& __c)
1894{
1895    return __c.begin();
1896}
1897
1898template <class _Cp>
1899_LIBCPP_INLINE_VISIBILITY
1900typename _Cp::const_iterator
1901begin(const _Cp& __c)
1902{
1903    return __c.begin();
1904}
1905
1906template <class _Cp>
1907_LIBCPP_INLINE_VISIBILITY
1908typename _Cp::iterator
1909end(_Cp& __c)
1910{
1911    return __c.end();
1912}
1913
1914template <class _Cp>
1915_LIBCPP_INLINE_VISIBILITY
1916typename _Cp::const_iterator
1917end(const _Cp& __c)
1918{
1919    return __c.end();
1920}
1921
1922#endif  // !defined(_LIBCPP_CXX03_LANG)
1923
1924#if _LIBCPP_STD_VER > 14
1925
1926// #if _LIBCPP_STD_VER > 11
1927// template <>
1928// struct _LIBCPP_TEMPLATE_VIS plus<void>
1929// {
1930//     template <class _T1, class _T2>
1931//     _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
1932//     auto operator()(_T1&& __t, _T2&& __u) const
1933//     _NOEXCEPT_(noexcept(_VSTD::forward<_T1>(__t) + _VSTD::forward<_T2>(__u)))
1934//     -> decltype        (_VSTD::forward<_T1>(__t) + _VSTD::forward<_T2>(__u))
1935//         { return        _VSTD::forward<_T1>(__t) + _VSTD::forward<_T2>(__u); }
1936//     typedef void is_transparent;
1937// };
1938// #endif
1939
1940template <class _Cont>
1941_LIBCPP_INLINE_VISIBILITY
1942constexpr auto size(const _Cont& __c)
1943_NOEXCEPT_(noexcept(__c.size()))
1944-> decltype        (__c.size())
1945{ return            __c.size(); }
1946
1947template <class _Tp, size_t _Sz>
1948_LIBCPP_INLINE_VISIBILITY
1949constexpr size_t size(const _Tp (&)[_Sz]) noexcept { return _Sz; }
1950
1951#if _LIBCPP_STD_VER > 17
1952template <class _Cont>
1953_LIBCPP_INLINE_VISIBILITY
1954constexpr auto ssize(const _Cont& __c)
1955_NOEXCEPT_(noexcept(static_cast<common_type_t<ptrdiff_t, make_signed_t<decltype(__c.size())>>>(__c.size())))
1956->                              common_type_t<ptrdiff_t, make_signed_t<decltype(__c.size())>>
1957{ return            static_cast<common_type_t<ptrdiff_t, make_signed_t<decltype(__c.size())>>>(__c.size()); }
1958
1959template <class _Tp, ptrdiff_t _Sz>
1960_LIBCPP_INLINE_VISIBILITY
1961constexpr ptrdiff_t ssize(const _Tp (&)[_Sz]) noexcept { return _Sz; }
1962#endif
1963
1964template <class _Cont>
1965_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
1966constexpr auto empty(const _Cont& __c)
1967_NOEXCEPT_(noexcept(__c.empty()))
1968-> decltype        (__c.empty())
1969{ return            __c.empty(); }
1970
1971template <class _Tp, size_t _Sz>
1972_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
1973constexpr bool empty(const _Tp (&)[_Sz]) noexcept { return false; }
1974
1975template <class _Ep>
1976_LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY
1977constexpr bool empty(initializer_list<_Ep> __il) noexcept { return __il.size() == 0; }
1978
1979template <class _Cont> constexpr
1980_LIBCPP_INLINE_VISIBILITY
1981auto data(_Cont& __c)
1982_NOEXCEPT_(noexcept(__c.data()))
1983-> decltype        (__c.data())
1984{ return            __c.data(); }
1985
1986template <class _Cont> constexpr
1987_LIBCPP_INLINE_VISIBILITY
1988auto data(const _Cont& __c)
1989_NOEXCEPT_(noexcept(__c.data()))
1990-> decltype        (__c.data())
1991{ return            __c.data(); }
1992
1993template <class _Tp, size_t _Sz>
1994_LIBCPP_INLINE_VISIBILITY
1995constexpr _Tp* data(_Tp (&__array)[_Sz]) noexcept { return __array; }
1996
1997template <class _Ep>
1998_LIBCPP_INLINE_VISIBILITY
1999constexpr const _Ep* data(initializer_list<_Ep> __il) noexcept { return __il.begin(); }
2000#endif
2001
2002
2003_LIBCPP_END_NAMESPACE_STD
2004
2005#endif  // _LIBCPP_ITERATOR
2006