1// -*- C++ -*-
2//===-------------------------- iterator ----------------------------------===//
3//
4//                     The LLVM Compiler Infrastructure
5//
6// This file is dual licensed under the MIT and the University of Illinois Open
7// Source Licenses. See LICENSE.TXT for details.
8//
9//===----------------------------------------------------------------------===//
10
11#ifndef _LIBCPP_ITERATOR
12#define _LIBCPP_ITERATOR
13
14/*
15    iterator synopsis
16
17namespace std
18{
19
20template<class Iterator>
21struct iterator_traits
22{
23    typedef typename Iterator::difference_type difference_type;
24    typedef typename Iterator::value_type value_type;
25    typedef typename Iterator::pointer pointer;
26    typedef typename Iterator::reference reference;
27    typedef typename Iterator::iterator_category iterator_category;
28};
29
30template<class T>
31struct iterator_traits<T*>
32{
33    typedef ptrdiff_t difference_type;
34    typedef T value_type;
35    typedef T* pointer;
36    typedef T& reference;
37    typedef random_access_iterator_tag iterator_category;
38};
39
40template<class Category, class T, class Distance = ptrdiff_t,
41         class Pointer = T*, class Reference = T&>
42struct iterator
43{
44    typedef T         value_type;
45    typedef Distance  difference_type;
46    typedef Pointer   pointer;
47    typedef Reference reference;
48    typedef Category  iterator_category;
49};
50
51struct input_iterator_tag  {};
52struct output_iterator_tag {};
53struct forward_iterator_tag       : public input_iterator_tag         {};
54struct bidirectional_iterator_tag : public forward_iterator_tag       {};
55struct random_access_iterator_tag : public bidirectional_iterator_tag {};
56
57// 27.4.3, iterator operations
58// extension: second argument not conforming to C++03
59template <class InputIterator>  // constexpr in C++17
60  constexpr void advance(InputIterator& i,
61             typename iterator_traits<InputIterator>::difference_type n);
62
63template <class InputIterator>  // constexpr in C++17
64  constexpr typename iterator_traits<InputIterator>::difference_type
65    distance(InputIterator first, InputIterator last);
66
67template <class InputIterator>  // constexpr in C++17
68  constexpr InputIterator next(InputIterator x,
69typename iterator_traits<InputIterator>::difference_type n = 1);
70
71template <class BidirectionalIterator>  // constexpr in C++17
72  constexpr BidirectionalIterator prev(BidirectionalIterator x,
73    typename iterator_traits<BidirectionalIterator>::difference_type n = 1);
74
75template <class Iterator>
76class reverse_iterator
77    : public iterator<typename iterator_traits<Iterator>::iterator_category,
78                      typename iterator_traits<Iterator>::value_type,
79                      typename iterator_traits<Iterator>::difference_type,
80                      typename iterator_traits<Iterator>::pointer,
81                      typename iterator_traits<Iterator>::reference>
82{
83protected:
84    Iterator current;
85public:
86    typedef Iterator                                            iterator_type;
87    typedef typename iterator_traits<Iterator>::difference_type difference_type;
88    typedef typename iterator_traits<Iterator>::reference       reference;
89    typedef typename iterator_traits<Iterator>::pointer         pointer;
90
91    constexpr reverse_iterator();
92    constexpr explicit reverse_iterator(Iterator x);
93    template <class U> constexpr reverse_iterator(const reverse_iterator<U>& u);
94    template <class U> constexpr reverse_iterator& operator=(const reverse_iterator<U>& u);
95    constexpr Iterator base() const;
96    constexpr reference operator*() const;
97    constexpr pointer   operator->() const;
98    constexpr reverse_iterator& operator++();
99    constexpr reverse_iterator  operator++(int);
100    constexpr reverse_iterator& operator--();
101    constexpr reverse_iterator  operator--(int);
102    constexpr reverse_iterator  operator+ (difference_type n) const;
103    constexpr reverse_iterator& operator+=(difference_type n);
104    constexpr reverse_iterator  operator- (difference_type n) const;
105    constexpr reverse_iterator& operator-=(difference_type n);
106    constexpr reference         operator[](difference_type n) const;
107};
108
109template <class Iterator1, class Iterator2>
110constexpr bool                          // constexpr in C++17
111operator==(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
112
113template <class Iterator1, class Iterator2>
114constexpr bool                          // constexpr in C++17
115operator<(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
116
117template <class Iterator1, class Iterator2>
118constexpr bool                          // constexpr in C++17
119operator!=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
120
121template <class Iterator1, class Iterator2>
122constexpr bool                          // constexpr in C++17
123operator>(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
124
125template <class Iterator1, class Iterator2>
126constexpr bool                          // constexpr in C++17
127operator>=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
128
129template <class Iterator1, class Iterator2>
130constexpr bool                          // constexpr in C++17
131operator<=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y);
132
133template <class Iterator1, class Iterator2>
134constexpr auto
135operator-(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y)
136-> decltype(__y.base() - __x.base());   // constexpr in C++17
137
138template <class Iterator>
139constexpr reverse_iterator<Iterator>
140operator+(typename reverse_iterator<Iterator>::difference_type n,
141          const reverse_iterator<Iterator>& x);   // constexpr in C++17
142
143template <class Iterator>
144constexpr reverse_iterator<Iterator> make_reverse_iterator(Iterator i); // C++14, constexpr in C++17
145
146template <class Container>
147class back_insert_iterator
148{
149protected:
150    Container* container;
151public:
152    typedef Container                   container_type;
153    typedef void                        value_type;
154    typedef void                        difference_type;
155    typedef void                        reference;
156    typedef void                        pointer;
157
158    explicit back_insert_iterator(Container& x);
159    back_insert_iterator& operator=(const typename Container::value_type& value);
160    back_insert_iterator& operator*();
161    back_insert_iterator& operator++();
162    back_insert_iterator  operator++(int);
163};
164
165template <class Container> back_insert_iterator<Container> back_inserter(Container& x);
166
167template <class Container>
168class front_insert_iterator
169{
170protected:
171    Container* container;
172public:
173    typedef Container                    container_type;
174    typedef void                         value_type;
175    typedef void                         difference_type;
176    typedef void                         reference;
177    typedef void                         pointer;
178
179    explicit front_insert_iterator(Container& x);
180    front_insert_iterator& operator=(const typename Container::value_type& value);
181    front_insert_iterator& operator*();
182    front_insert_iterator& operator++();
183    front_insert_iterator  operator++(int);
184};
185
186template <class Container> front_insert_iterator<Container> front_inserter(Container& x);
187
188template <class Container>
189class insert_iterator
190{
191protected:
192    Container* container;
193    typename Container::iterator iter;
194public:
195    typedef Container              container_type;
196    typedef void                   value_type;
197    typedef void                   difference_type;
198    typedef void                   reference;
199    typedef void                   pointer;
200
201    insert_iterator(Container& x, typename Container::iterator i);
202    insert_iterator& operator=(const typename Container::value_type& value);
203    insert_iterator& operator*();
204    insert_iterator& operator++();
205    insert_iterator& operator++(int);
206};
207
208template <class Container, class Iterator>
209insert_iterator<Container> inserter(Container& x, Iterator i);
210
211template <class Iterator>
212class move_iterator {
213public:
214    typedef Iterator                                              iterator_type;
215    typedef typename iterator_traits<Iterator>::difference_type   difference_type;
216    typedef Iterator                                              pointer;
217    typedef typename iterator_traits<Iterator>::value_type        value_type;
218    typedef typename iterator_traits<Iterator>::iterator_category iterator_category;
219    typedef value_type&&                                          reference;
220
221    constexpr move_iterator();  // all the constexprs are in C++17
222    constexpr explicit move_iterator(Iterator i);
223    template <class U>
224      constexpr move_iterator(const move_iterator<U>& u);
225    template <class U>
226      constexpr move_iterator& operator=(const move_iterator<U>& u);
227    constexpr iterator_type base() const;
228    constexpr reference operator*() const;
229    constexpr pointer operator->() const;
230    constexpr move_iterator& operator++();
231    constexpr move_iterator operator++(int);
232    constexpr move_iterator& operator--();
233    constexpr move_iterator operator--(int);
234    constexpr move_iterator operator+(difference_type n) const;
235    constexpr move_iterator& operator+=(difference_type n);
236    constexpr move_iterator operator-(difference_type n) const;
237    constexpr move_iterator& operator-=(difference_type n);
238    constexpr unspecified operator[](difference_type n) const;
239private:
240    Iterator current; // exposition only
241};
242
243template <class Iterator1, class Iterator2>
244constexpr bool   // constexpr in C++17
245operator==(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
246
247template <class Iterator1, class Iterator2>
248constexpr bool   // constexpr in C++17
249operator!=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
250
251template <class Iterator1, class Iterator2>
252constexpr bool   // constexpr in C++17
253operator<(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
254
255template <class Iterator1, class Iterator2>
256constexpr bool   // constexpr in C++17
257operator<=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
258
259template <class Iterator1, class Iterator2>
260constexpr bool   // constexpr in C++17
261operator>(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
262
263template <class Iterator1, class Iterator2>
264constexpr bool   // constexpr in C++17
265operator>=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
266
267template <class Iterator1, class Iterator2>
268constexpr auto   // constexpr in C++17
269operator-(const move_iterator<Iterator1>& x,
270          const move_iterator<Iterator2>& y) -> decltype(x.base() - y.base());
271
272template <class Iterator>
273constexpr move_iterator<Iterator> operator+(   // constexpr in C++17
274            typename move_iterator<Iterator>::difference_type n,
275            const move_iterator<Iterator>& x);
276
277template <class Iterator>   // constexpr in C++17
278constexpr  move_iterator<Iterator> make_move_iterator(const Iterator& i);
279
280
281template <class T, class charT = char, class traits = char_traits<charT>, class Distance = ptrdiff_t>
282class istream_iterator
283    : public iterator<input_iterator_tag, T, Distance, const T*, const T&>
284{
285public:
286    typedef charT char_type;
287    typedef traits traits_type;
288    typedef basic_istream<charT,traits> istream_type;
289
290    constexpr istream_iterator();
291    istream_iterator(istream_type& s);
292    istream_iterator(const istream_iterator& x);
293    ~istream_iterator();
294
295    const T& operator*() const;
296    const T* operator->() const;
297    istream_iterator& operator++();
298    istream_iterator  operator++(int);
299};
300
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);
304template <class T, class charT, class traits, class Distance>
305bool operator!=(const istream_iterator<T,charT,traits,Distance>& x,
306                const istream_iterator<T,charT,traits,Distance>& y);
307
308template <class T, class charT = char, class traits = char_traits<charT> >
309class ostream_iterator
310    : public iterator<output_iterator_tag, void, void, void ,void>
311{
312public:
313    typedef charT char_type;
314    typedef traits traits_type;
315    typedef basic_ostream<charT,traits> ostream_type;
316
317    ostream_iterator(ostream_type& s);
318    ostream_iterator(ostream_type& s, const charT* delimiter);
319    ostream_iterator(const ostream_iterator& x);
320    ~ostream_iterator();
321    ostream_iterator& operator=(const T& value);
322
323    ostream_iterator& operator*();
324    ostream_iterator& operator++();
325    ostream_iterator& operator++(int);
326};
327
328template<class charT, class traits = char_traits<charT> >
329class istreambuf_iterator
330    : public iterator<input_iterator_tag, charT,
331                      typename traits::off_type, unspecified,
332                      charT>
333{
334public:
335    typedef charT                         char_type;
336    typedef traits                        traits_type;
337    typedef typename traits::int_type     int_type;
338    typedef basic_streambuf<charT,traits> streambuf_type;
339    typedef basic_istream<charT,traits>   istream_type;
340
341    istreambuf_iterator() noexcept;
342    istreambuf_iterator(istream_type& s) noexcept;
343    istreambuf_iterator(streambuf_type* s) noexcept;
344    istreambuf_iterator(a-private-type) noexcept;
345
346    charT                operator*() const;
347    pointer operator->() const;
348    istreambuf_iterator& operator++();
349    a-private-type       operator++(int);
350
351    bool equal(const istreambuf_iterator& b) const;
352};
353
354template <class charT, class traits>
355bool operator==(const istreambuf_iterator<charT,traits>& a,
356                const istreambuf_iterator<charT,traits>& b);
357template <class charT, class traits>
358bool operator!=(const istreambuf_iterator<charT,traits>& a,
359                const istreambuf_iterator<charT,traits>& b);
360
361template <class charT, class traits = char_traits<charT> >
362class ostreambuf_iterator
363    : public iterator<output_iterator_tag, void, void, void, void>
364{
365public:
366    typedef charT                         char_type;
367    typedef traits                        traits_type;
368    typedef basic_streambuf<charT,traits> streambuf_type;
369    typedef basic_ostream<charT,traits>   ostream_type;
370
371    ostreambuf_iterator(ostream_type& s) noexcept;
372    ostreambuf_iterator(streambuf_type* s) noexcept;
373    ostreambuf_iterator& operator=(charT c);
374    ostreambuf_iterator& operator*();
375    ostreambuf_iterator& operator++();
376    ostreambuf_iterator& operator++(int);
377    bool failed() const noexcept;
378};
379
380template <class C> constexpr auto begin(C& c) -> decltype(c.begin());
381template <class C> constexpr auto begin(const C& c) -> decltype(c.begin());
382template <class C> constexpr auto end(C& c) -> decltype(c.end());
383template <class C> constexpr auto end(const C& c) -> decltype(c.end());
384template <class T, size_t N> constexpr T* begin(T (&array)[N]);
385template <class T, size_t N> constexpr T* end(T (&array)[N]);
386
387template <class C> auto constexpr cbegin(const C& c) -> decltype(std::begin(c));        // C++14
388template <class C> auto constexpr cend(const C& c) -> decltype(std::end(c));            // C++14
389template <class C> auto constexpr rbegin(C& c) -> decltype(c.rbegin());                 // C++14
390template <class C> auto constexpr rbegin(const C& c) -> decltype(c.rbegin());           // C++14
391template <class C> auto constexpr rend(C& c) -> decltype(c.rend());                     // C++14
392template <class C> constexpr auto rend(const C& c) -> decltype(c.rend());               // C++14
393template <class E> reverse_iterator<const E*> constexpr rbegin(initializer_list<E> il); // C++14
394template <class E> reverse_iterator<const E*> constexpr rend(initializer_list<E> il);   // C++14
395template <class T, size_t N> reverse_iterator<T*> constexpr rbegin(T (&array)[N]);      // C++14
396template <class T, size_t N> reverse_iterator<T*> constexpr rend(T (&array)[N]);        // C++14
397template <class C> constexpr auto crbegin(const C& c) -> decltype(std::rbegin(c));      // C++14
398template <class C> constexpr auto crend(const C& c) -> decltype(std::rend(c));          // C++14
399
400// 24.8, container access:
401template <class C> constexpr auto size(const C& c) -> decltype(c.size());         // C++17
402template <class T, size_t N> constexpr size_t size(const T (&array)[N]) noexcept; // C++17
403template <class C> constexpr auto empty(const C& c) -> decltype(c.empty());       // C++17
404template <class T, size_t N> constexpr bool empty(const T (&array)[N]) noexcept;  // C++17
405template <class E> constexpr bool empty(initializer_list<E> il) noexcept;         // C++17
406template <class C> constexpr auto data(C& c) -> decltype(c.data());               // C++17
407template <class C> constexpr auto data(const C& c) -> decltype(c.data());         // C++17
408template <class T, size_t N> constexpr T* data(T (&array)[N]) noexcept;           // C++17
409template <class E> constexpr const E* data(initializer_list<E> il) noexcept;      // C++17
410
411}  // std
412
413*/
414
415#include <__config>
416#include <iosfwd> // for forward declarations of vector and string.
417#include <__functional_base>
418#include <type_traits>
419#include <cstddef>
420#include <initializer_list>
421#ifdef __APPLE__
422#include <Availability.h>
423#endif
424
425#include <__debug>
426
427#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
428#pragma GCC system_header
429#endif
430
431_LIBCPP_BEGIN_NAMESPACE_STD
432
433struct _LIBCPP_TEMPLATE_VIS input_iterator_tag {};
434struct _LIBCPP_TEMPLATE_VIS output_iterator_tag {};
435struct _LIBCPP_TEMPLATE_VIS forward_iterator_tag       : public input_iterator_tag {};
436struct _LIBCPP_TEMPLATE_VIS bidirectional_iterator_tag : public forward_iterator_tag {};
437struct _LIBCPP_TEMPLATE_VIS random_access_iterator_tag : public bidirectional_iterator_tag {};
438
439template <class _Tp>
440struct __has_iterator_category
441{
442private:
443    struct __two {char __lx; char __lxx;};
444    template <class _Up> static __two __test(...);
445    template <class _Up> static char __test(typename _Up::iterator_category* = 0);
446public:
447    static const bool value = sizeof(__test<_Tp>(0)) == 1;
448};
449
450template <class _Iter, bool> struct __iterator_traits_impl {};
451
452template <class _Iter>
453struct __iterator_traits_impl<_Iter, true>
454{
455    typedef typename _Iter::difference_type   difference_type;
456    typedef typename _Iter::value_type        value_type;
457    typedef typename _Iter::pointer           pointer;
458    typedef typename _Iter::reference         reference;
459    typedef typename _Iter::iterator_category iterator_category;
460};
461
462template <class _Iter, bool> struct __iterator_traits {};
463
464template <class _Iter>
465struct __iterator_traits<_Iter, true>
466    :  __iterator_traits_impl
467      <
468        _Iter,
469        is_convertible<typename _Iter::iterator_category, input_iterator_tag>::value ||
470        is_convertible<typename _Iter::iterator_category, output_iterator_tag>::value
471      >
472{};
473
474// iterator_traits<Iterator> will only have the nested types if Iterator::iterator_category
475//    exists.  Else iterator_traits<Iterator> will be an empty class.  This is a
476//    conforming extension which allows some programs to compile and behave as
477//    the client expects instead of failing at compile time.
478
479template <class _Iter>
480struct _LIBCPP_TEMPLATE_VIS iterator_traits
481    : __iterator_traits<_Iter, __has_iterator_category<_Iter>::value> {};
482
483template<class _Tp>
484struct _LIBCPP_TEMPLATE_VIS iterator_traits<_Tp*>
485{
486    typedef ptrdiff_t difference_type;
487    typedef typename remove_cv<_Tp>::type value_type;
488    typedef _Tp* pointer;
489    typedef _Tp& reference;
490    typedef random_access_iterator_tag iterator_category;
491};
492
493template <class _Tp, class _Up, bool = __has_iterator_category<iterator_traits<_Tp> >::value>
494struct __has_iterator_category_convertible_to
495    : public integral_constant<bool, is_convertible<typename iterator_traits<_Tp>::iterator_category, _Up>::value>
496{};
497
498template <class _Tp, class _Up>
499struct __has_iterator_category_convertible_to<_Tp, _Up, false> : public false_type {};
500
501template <class _Tp>
502struct __is_input_iterator : public __has_iterator_category_convertible_to<_Tp, input_iterator_tag> {};
503
504template <class _Tp>
505struct __is_forward_iterator : public __has_iterator_category_convertible_to<_Tp, forward_iterator_tag> {};
506
507template <class _Tp>
508struct __is_bidirectional_iterator : public __has_iterator_category_convertible_to<_Tp, bidirectional_iterator_tag> {};
509
510template <class _Tp>
511struct __is_random_access_iterator : public __has_iterator_category_convertible_to<_Tp, random_access_iterator_tag> {};
512
513template <class _Tp>
514struct __is_exactly_input_iterator
515    : public integral_constant<bool,
516         __has_iterator_category_convertible_to<_Tp, input_iterator_tag>::value &&
517        !__has_iterator_category_convertible_to<_Tp, forward_iterator_tag>::value> {};
518
519template<class _Category, class _Tp, class _Distance = ptrdiff_t,
520         class _Pointer = _Tp*, class _Reference = _Tp&>
521struct _LIBCPP_TEMPLATE_VIS iterator
522{
523    typedef _Tp        value_type;
524    typedef _Distance  difference_type;
525    typedef _Pointer   pointer;
526    typedef _Reference reference;
527    typedef _Category  iterator_category;
528};
529
530template <class _InputIter>
531inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
532void __advance(_InputIter& __i,
533             typename iterator_traits<_InputIter>::difference_type __n, input_iterator_tag)
534{
535    for (; __n > 0; --__n)
536        ++__i;
537}
538
539template <class _BiDirIter>
540inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
541void __advance(_BiDirIter& __i,
542             typename iterator_traits<_BiDirIter>::difference_type __n, bidirectional_iterator_tag)
543{
544    if (__n >= 0)
545        for (; __n > 0; --__n)
546            ++__i;
547    else
548        for (; __n < 0; ++__n)
549            --__i;
550}
551
552template <class _RandIter>
553inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
554void __advance(_RandIter& __i,
555             typename iterator_traits<_RandIter>::difference_type __n, random_access_iterator_tag)
556{
557   __i += __n;
558}
559
560template <class _InputIter>
561inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
562void advance(_InputIter& __i,
563             typename iterator_traits<_InputIter>::difference_type __n)
564{
565    __advance(__i, __n, typename iterator_traits<_InputIter>::iterator_category());
566}
567
568template <class _InputIter>
569inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
570typename iterator_traits<_InputIter>::difference_type
571__distance(_InputIter __first, _InputIter __last, input_iterator_tag)
572{
573    typename iterator_traits<_InputIter>::difference_type __r(0);
574    for (; __first != __last; ++__first)
575        ++__r;
576    return __r;
577}
578
579template <class _RandIter>
580inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
581typename iterator_traits<_RandIter>::difference_type
582__distance(_RandIter __first, _RandIter __last, random_access_iterator_tag)
583{
584    return __last - __first;
585}
586
587template <class _InputIter>
588inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
589typename iterator_traits<_InputIter>::difference_type
590distance(_InputIter __first, _InputIter __last)
591{
592    return __distance(__first, __last, typename iterator_traits<_InputIter>::iterator_category());
593}
594
595template <class _InputIter>
596inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
597typename enable_if
598<
599    __is_input_iterator<_InputIter>::value,
600    _InputIter
601>::type
602next(_InputIter __x,
603     typename iterator_traits<_InputIter>::difference_type __n = 1)
604{
605    _VSTD::advance(__x, __n);
606    return __x;
607}
608
609template <class _BidirectionalIter>
610inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
611typename enable_if
612<
613    __is_bidirectional_iterator<_BidirectionalIter>::value,
614    _BidirectionalIter
615>::type
616prev(_BidirectionalIter __x,
617     typename iterator_traits<_BidirectionalIter>::difference_type __n = 1)
618{
619    _VSTD::advance(__x, -__n);
620    return __x;
621}
622
623
624template <class _Tp, class = void>
625struct __is_stashing_iterator : false_type {};
626
627template <class _Tp>
628struct __is_stashing_iterator<_Tp, typename __void_t<typename _Tp::__stashing_iterator_tag>::type>
629  : true_type {};
630
631template <class _Iter>
632class _LIBCPP_TEMPLATE_VIS reverse_iterator
633    : public iterator<typename iterator_traits<_Iter>::iterator_category,
634                      typename iterator_traits<_Iter>::value_type,
635                      typename iterator_traits<_Iter>::difference_type,
636                      typename iterator_traits<_Iter>::pointer,
637                      typename iterator_traits<_Iter>::reference>
638{
639private:
640    /*mutable*/ _Iter __t;  // no longer used as of LWG #2360, not removed due to ABI break
641
642    static_assert(!__is_stashing_iterator<_Iter>::value,
643      "The specified iterator type cannot be used with reverse_iterator; "
644      "Using stashing iterators with reverse_iterator causes undefined behavior");
645
646protected:
647    _Iter current;
648public:
649    typedef _Iter                                            iterator_type;
650    typedef typename iterator_traits<_Iter>::difference_type difference_type;
651    typedef typename iterator_traits<_Iter>::reference       reference;
652    typedef typename iterator_traits<_Iter>::pointer         pointer;
653
654    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
655    reverse_iterator() : __t(), current() {}
656    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
657    explicit reverse_iterator(_Iter __x) : __t(__x), current(__x) {}
658    template <class _Up>
659        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
660        reverse_iterator(const reverse_iterator<_Up>& __u) : __t(__u.base()), current(__u.base()) {}
661    template <class _Up>
662        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
663        reverse_iterator& operator=(const reverse_iterator<_Up>& __u)
664            { __t = current = __u.base(); return *this; }
665    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
666    _Iter base() const {return current;}
667    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
668    reference operator*() const {_Iter __tmp = current; return *--__tmp;}
669    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
670    pointer  operator->() const {return _VSTD::addressof(operator*());}
671    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
672    reverse_iterator& operator++() {--current; return *this;}
673    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
674    reverse_iterator  operator++(int) {reverse_iterator __tmp(*this); --current; return __tmp;}
675    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
676    reverse_iterator& operator--() {++current; return *this;}
677    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
678    reverse_iterator  operator--(int) {reverse_iterator __tmp(*this); ++current; return __tmp;}
679    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
680    reverse_iterator  operator+ (difference_type __n) const {return reverse_iterator(current - __n);}
681    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
682    reverse_iterator& operator+=(difference_type __n) {current -= __n; return *this;}
683    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
684    reverse_iterator  operator- (difference_type __n) const {return reverse_iterator(current + __n);}
685    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
686    reverse_iterator& operator-=(difference_type __n) {current += __n; return *this;}
687    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
688    reference         operator[](difference_type __n) const {return *(*this + __n);}
689};
690
691template <class _Iter1, class _Iter2>
692inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
693bool
694operator==(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
695{
696    return __x.base() == __y.base();
697}
698
699template <class _Iter1, class _Iter2>
700inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
701bool
702operator<(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
703{
704    return __x.base() > __y.base();
705}
706
707template <class _Iter1, class _Iter2>
708inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
709bool
710operator!=(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
711{
712    return __x.base() != __y.base();
713}
714
715template <class _Iter1, class _Iter2>
716inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
717bool
718operator>(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
719{
720    return __x.base() < __y.base();
721}
722
723template <class _Iter1, class _Iter2>
724inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
725bool
726operator>=(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
727{
728    return __x.base() <= __y.base();
729}
730
731template <class _Iter1, class _Iter2>
732inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
733bool
734operator<=(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
735{
736    return __x.base() >= __y.base();
737}
738
739#ifndef _LIBCPP_CXX03_LANG
740template <class _Iter1, class _Iter2>
741inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
742auto
743operator-(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
744-> decltype(__y.base() - __x.base())
745{
746    return __y.base() - __x.base();
747}
748#else
749template <class _Iter1, class _Iter2>
750inline _LIBCPP_INLINE_VISIBILITY
751typename reverse_iterator<_Iter1>::difference_type
752operator-(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
753{
754    return __y.base() - __x.base();
755}
756#endif
757
758template <class _Iter>
759inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
760reverse_iterator<_Iter>
761operator+(typename reverse_iterator<_Iter>::difference_type __n, const reverse_iterator<_Iter>& __x)
762{
763    return reverse_iterator<_Iter>(__x.base() - __n);
764}
765
766#if _LIBCPP_STD_VER > 11
767template <class _Iter>
768inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
769reverse_iterator<_Iter> make_reverse_iterator(_Iter __i)
770{
771    return reverse_iterator<_Iter>(__i);
772}
773#endif
774
775template <class _Container>
776class _LIBCPP_TEMPLATE_VIS back_insert_iterator
777    : public iterator<output_iterator_tag,
778                      void,
779                      void,
780                      void,
781                      void>
782{
783protected:
784    _Container* container;
785public:
786    typedef _Container container_type;
787
788    _LIBCPP_INLINE_VISIBILITY explicit back_insert_iterator(_Container& __x) : container(_VSTD::addressof(__x)) {}
789    _LIBCPP_INLINE_VISIBILITY back_insert_iterator& operator=(const typename _Container::value_type& __value_)
790        {container->push_back(__value_); return *this;}
791#ifndef _LIBCPP_CXX03_LANG
792    _LIBCPP_INLINE_VISIBILITY back_insert_iterator& operator=(typename _Container::value_type&& __value_)
793        {container->push_back(_VSTD::move(__value_)); return *this;}
794#endif  // _LIBCPP_CXX03_LANG
795    _LIBCPP_INLINE_VISIBILITY back_insert_iterator& operator*()     {return *this;}
796    _LIBCPP_INLINE_VISIBILITY back_insert_iterator& operator++()    {return *this;}
797    _LIBCPP_INLINE_VISIBILITY back_insert_iterator  operator++(int) {return *this;}
798};
799
800template <class _Container>
801inline _LIBCPP_INLINE_VISIBILITY
802back_insert_iterator<_Container>
803back_inserter(_Container& __x)
804{
805    return back_insert_iterator<_Container>(__x);
806}
807
808template <class _Container>
809class _LIBCPP_TEMPLATE_VIS front_insert_iterator
810    : public iterator<output_iterator_tag,
811                      void,
812                      void,
813                      void,
814                      void>
815{
816protected:
817    _Container* container;
818public:
819    typedef _Container container_type;
820
821    _LIBCPP_INLINE_VISIBILITY explicit front_insert_iterator(_Container& __x) : container(_VSTD::addressof(__x)) {}
822    _LIBCPP_INLINE_VISIBILITY front_insert_iterator& operator=(const typename _Container::value_type& __value_)
823        {container->push_front(__value_); return *this;}
824#ifndef _LIBCPP_CXX03_LANG
825    _LIBCPP_INLINE_VISIBILITY front_insert_iterator& operator=(typename _Container::value_type&& __value_)
826        {container->push_front(_VSTD::move(__value_)); return *this;}
827#endif  // _LIBCPP_CXX03_LANG
828    _LIBCPP_INLINE_VISIBILITY front_insert_iterator& operator*()     {return *this;}
829    _LIBCPP_INLINE_VISIBILITY front_insert_iterator& operator++()    {return *this;}
830    _LIBCPP_INLINE_VISIBILITY front_insert_iterator  operator++(int) {return *this;}
831};
832
833template <class _Container>
834inline _LIBCPP_INLINE_VISIBILITY
835front_insert_iterator<_Container>
836front_inserter(_Container& __x)
837{
838    return front_insert_iterator<_Container>(__x);
839}
840
841template <class _Container>
842class _LIBCPP_TEMPLATE_VIS insert_iterator
843    : public iterator<output_iterator_tag,
844                      void,
845                      void,
846                      void,
847                      void>
848{
849protected:
850    _Container* container;
851    typename _Container::iterator iter;
852public:
853    typedef _Container container_type;
854
855    _LIBCPP_INLINE_VISIBILITY insert_iterator(_Container& __x, typename _Container::iterator __i)
856        : container(_VSTD::addressof(__x)), iter(__i) {}
857    _LIBCPP_INLINE_VISIBILITY insert_iterator& operator=(const typename _Container::value_type& __value_)
858        {iter = container->insert(iter, __value_); ++iter; return *this;}
859#ifndef _LIBCPP_CXX03_LANG
860    _LIBCPP_INLINE_VISIBILITY insert_iterator& operator=(typename _Container::value_type&& __value_)
861        {iter = container->insert(iter, _VSTD::move(__value_)); ++iter; return *this;}
862#endif  // _LIBCPP_CXX03_LANG
863    _LIBCPP_INLINE_VISIBILITY insert_iterator& operator*()        {return *this;}
864    _LIBCPP_INLINE_VISIBILITY insert_iterator& operator++()       {return *this;}
865    _LIBCPP_INLINE_VISIBILITY insert_iterator& operator++(int)    {return *this;}
866};
867
868template <class _Container>
869inline _LIBCPP_INLINE_VISIBILITY
870insert_iterator<_Container>
871inserter(_Container& __x, typename _Container::iterator __i)
872{
873    return insert_iterator<_Container>(__x, __i);
874}
875
876template <class _Tp, class _CharT = char,
877          class _Traits = char_traits<_CharT>, class _Distance = ptrdiff_t>
878class _LIBCPP_TEMPLATE_VIS istream_iterator
879    : public iterator<input_iterator_tag, _Tp, _Distance, const _Tp*, const _Tp&>
880{
881public:
882    typedef _CharT char_type;
883    typedef _Traits traits_type;
884    typedef basic_istream<_CharT,_Traits> istream_type;
885private:
886    istream_type* __in_stream_;
887    _Tp __value_;
888public:
889    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR istream_iterator() : __in_stream_(0), __value_() {}
890    _LIBCPP_INLINE_VISIBILITY istream_iterator(istream_type& __s) : __in_stream_(_VSTD::addressof(__s))
891        {
892            if (!(*__in_stream_ >> __value_))
893                __in_stream_ = 0;
894        }
895
896    _LIBCPP_INLINE_VISIBILITY const _Tp& operator*() const {return __value_;}
897    _LIBCPP_INLINE_VISIBILITY const _Tp* operator->() const {return _VSTD::addressof((operator*()));}
898    _LIBCPP_INLINE_VISIBILITY istream_iterator& operator++()
899        {
900            if (!(*__in_stream_ >> __value_))
901                __in_stream_ = 0;
902            return *this;
903        }
904    _LIBCPP_INLINE_VISIBILITY istream_iterator  operator++(int)
905        {istream_iterator __t(*this); ++(*this); return __t;}
906
907    friend _LIBCPP_INLINE_VISIBILITY
908    bool operator==(const istream_iterator& __x, const istream_iterator& __y)
909        {return __x.__in_stream_ == __y.__in_stream_;}
910
911    friend _LIBCPP_INLINE_VISIBILITY
912    bool operator!=(const istream_iterator& __x, const istream_iterator& __y)
913        {return !(__x == __y);}
914};
915
916template <class _Tp, class _CharT = char, class _Traits = char_traits<_CharT> >
917class _LIBCPP_TEMPLATE_VIS ostream_iterator
918    : public iterator<output_iterator_tag, void, void, void, void>
919{
920public:
921    typedef _CharT char_type;
922    typedef _Traits traits_type;
923    typedef basic_ostream<_CharT,_Traits> ostream_type;
924private:
925    ostream_type* __out_stream_;
926    const char_type* __delim_;
927public:
928    _LIBCPP_INLINE_VISIBILITY ostream_iterator(ostream_type& __s) _NOEXCEPT
929        : __out_stream_(_VSTD::addressof(__s)), __delim_(0) {}
930    _LIBCPP_INLINE_VISIBILITY ostream_iterator(ostream_type& __s, const _CharT* __delimiter) _NOEXCEPT
931        : __out_stream_(_VSTD::addressof(__s)), __delim_(__delimiter) {}
932    _LIBCPP_INLINE_VISIBILITY ostream_iterator& operator=(const _Tp& __value_)
933        {
934            *__out_stream_ << __value_;
935            if (__delim_)
936                *__out_stream_ << __delim_;
937            return *this;
938        }
939
940    _LIBCPP_INLINE_VISIBILITY ostream_iterator& operator*()     {return *this;}
941    _LIBCPP_INLINE_VISIBILITY ostream_iterator& operator++()    {return *this;}
942    _LIBCPP_INLINE_VISIBILITY ostream_iterator& operator++(int) {return *this;}
943};
944
945template<class _CharT, class _Traits>
946class _LIBCPP_TEMPLATE_VIS istreambuf_iterator
947    : public iterator<input_iterator_tag, _CharT,
948                      typename _Traits::off_type, _CharT*,
949                      _CharT>
950{
951public:
952    typedef _CharT                          char_type;
953    typedef _Traits                         traits_type;
954    typedef typename _Traits::int_type      int_type;
955    typedef basic_streambuf<_CharT,_Traits> streambuf_type;
956    typedef basic_istream<_CharT,_Traits>   istream_type;
957private:
958    mutable streambuf_type* __sbuf_;
959
960    class __proxy
961    {
962        char_type __keep_;
963        streambuf_type* __sbuf_;
964        _LIBCPP_INLINE_VISIBILITY __proxy(char_type __c, streambuf_type* __s)
965            : __keep_(__c), __sbuf_(__s) {}
966        friend class istreambuf_iterator;
967    public:
968        _LIBCPP_INLINE_VISIBILITY char_type operator*() const {return __keep_;}
969    };
970
971    _LIBCPP_INLINE_VISIBILITY
972    bool __test_for_eof() const
973    {
974        if (__sbuf_ && traits_type::eq_int_type(__sbuf_->sgetc(), traits_type::eof()))
975            __sbuf_ = 0;
976        return __sbuf_ == 0;
977    }
978public:
979    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR istreambuf_iterator() _NOEXCEPT : __sbuf_(0) {}
980    _LIBCPP_INLINE_VISIBILITY istreambuf_iterator(istream_type& __s) _NOEXCEPT
981        : __sbuf_(__s.rdbuf()) {}
982    _LIBCPP_INLINE_VISIBILITY istreambuf_iterator(streambuf_type* __s) _NOEXCEPT
983        : __sbuf_(__s) {}
984    _LIBCPP_INLINE_VISIBILITY istreambuf_iterator(const __proxy& __p) _NOEXCEPT
985        : __sbuf_(__p.__sbuf_) {}
986
987    _LIBCPP_INLINE_VISIBILITY char_type  operator*() const
988        {return static_cast<char_type>(__sbuf_->sgetc());}
989    _LIBCPP_INLINE_VISIBILITY istreambuf_iterator& operator++()
990        {
991            __sbuf_->sbumpc();
992            return *this;
993        }
994    _LIBCPP_INLINE_VISIBILITY __proxy              operator++(int)
995        {
996            return __proxy(__sbuf_->sbumpc(), __sbuf_);
997        }
998
999    _LIBCPP_INLINE_VISIBILITY bool equal(const istreambuf_iterator& __b) const
1000        {return __test_for_eof() == __b.__test_for_eof();}
1001};
1002
1003template <class _CharT, class _Traits>
1004inline _LIBCPP_INLINE_VISIBILITY
1005bool operator==(const istreambuf_iterator<_CharT,_Traits>& __a,
1006                const istreambuf_iterator<_CharT,_Traits>& __b)
1007                {return __a.equal(__b);}
1008
1009template <class _CharT, class _Traits>
1010inline _LIBCPP_INLINE_VISIBILITY
1011bool operator!=(const istreambuf_iterator<_CharT,_Traits>& __a,
1012                const istreambuf_iterator<_CharT,_Traits>& __b)
1013                {return !__a.equal(__b);}
1014
1015template <class _CharT, class _Traits>
1016class _LIBCPP_TEMPLATE_VIS ostreambuf_iterator
1017    : public iterator<output_iterator_tag, void, void, void, void>
1018{
1019public:
1020    typedef _CharT                          char_type;
1021    typedef _Traits                         traits_type;
1022    typedef basic_streambuf<_CharT,_Traits> streambuf_type;
1023    typedef basic_ostream<_CharT,_Traits>   ostream_type;
1024private:
1025    streambuf_type* __sbuf_;
1026public:
1027    _LIBCPP_INLINE_VISIBILITY ostreambuf_iterator(ostream_type& __s) _NOEXCEPT
1028        : __sbuf_(__s.rdbuf()) {}
1029    _LIBCPP_INLINE_VISIBILITY ostreambuf_iterator(streambuf_type* __s) _NOEXCEPT
1030        : __sbuf_(__s) {}
1031    _LIBCPP_INLINE_VISIBILITY ostreambuf_iterator& operator=(_CharT __c)
1032        {
1033            if (__sbuf_ && traits_type::eq_int_type(__sbuf_->sputc(__c), traits_type::eof()))
1034                __sbuf_ = 0;
1035            return *this;
1036        }
1037    _LIBCPP_INLINE_VISIBILITY ostreambuf_iterator& operator*()     {return *this;}
1038    _LIBCPP_INLINE_VISIBILITY ostreambuf_iterator& operator++()    {return *this;}
1039    _LIBCPP_INLINE_VISIBILITY ostreambuf_iterator& operator++(int) {return *this;}
1040    _LIBCPP_INLINE_VISIBILITY bool failed() const _NOEXCEPT {return __sbuf_ == 0;}
1041
1042#if !defined(__APPLE__) || \
1043    (defined(__MAC_OS_X_VERSION_MIN_REQUIRED) && __MAC_OS_X_VERSION_MIN_REQUIRED > __MAC_10_8) || \
1044    (defined(__IPHONE_OS_VERSION_MIN_REQUIRED) && __IPHONE_OS_VERSION_MIN_REQUIRED > __IPHONE_6_0)
1045
1046    template <class _Ch, class _Tr>
1047    friend
1048    _LIBCPP_HIDDEN
1049    ostreambuf_iterator<_Ch, _Tr>
1050    __pad_and_output(ostreambuf_iterator<_Ch, _Tr> __s,
1051                     const _Ch* __ob, const _Ch* __op, const _Ch* __oe,
1052                     ios_base& __iob, _Ch __fl);
1053#endif
1054};
1055
1056template <class _Iter>
1057class _LIBCPP_TEMPLATE_VIS move_iterator
1058{
1059private:
1060    _Iter __i;
1061public:
1062    typedef _Iter                                            iterator_type;
1063    typedef typename iterator_traits<iterator_type>::iterator_category iterator_category;
1064    typedef typename iterator_traits<iterator_type>::value_type value_type;
1065    typedef typename iterator_traits<iterator_type>::difference_type difference_type;
1066    typedef iterator_type pointer;
1067#ifndef _LIBCPP_CXX03_LANG
1068    typedef typename iterator_traits<iterator_type>::reference __reference;
1069    typedef typename conditional<
1070            is_reference<__reference>::value,
1071            typename remove_reference<__reference>::type&&,
1072            __reference
1073        >::type reference;
1074#else
1075    typedef typename iterator_traits<iterator_type>::reference reference;
1076#endif
1077
1078    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1079    move_iterator() : __i() {}
1080    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1081    explicit move_iterator(_Iter __x) : __i(__x) {}
1082    template <class _Up>
1083      _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1084      move_iterator(const move_iterator<_Up>& __u) : __i(__u.base()) {}
1085    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14 _Iter base() const {return __i;}
1086    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1087    reference operator*() const { return static_cast<reference>(*__i); }
1088    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1089    pointer  operator->() const { return __i;}
1090    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1091    move_iterator& operator++() {++__i; return *this;}
1092    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1093    move_iterator  operator++(int) {move_iterator __tmp(*this); ++__i; return __tmp;}
1094    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1095    move_iterator& operator--() {--__i; return *this;}
1096    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1097    move_iterator  operator--(int) {move_iterator __tmp(*this); --__i; return __tmp;}
1098    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1099    move_iterator  operator+ (difference_type __n) const {return move_iterator(__i + __n);}
1100    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1101    move_iterator& operator+=(difference_type __n) {__i += __n; return *this;}
1102    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1103    move_iterator  operator- (difference_type __n) const {return move_iterator(__i - __n);}
1104    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1105    move_iterator& operator-=(difference_type __n) {__i -= __n; return *this;}
1106    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1107    reference operator[](difference_type __n) const { return static_cast<reference>(__i[__n]); }
1108};
1109
1110template <class _Iter1, class _Iter2>
1111inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1112bool
1113operator==(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
1114{
1115    return __x.base() == __y.base();
1116}
1117
1118template <class _Iter1, class _Iter2>
1119inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1120bool
1121operator<(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
1122{
1123    return __x.base() < __y.base();
1124}
1125
1126template <class _Iter1, class _Iter2>
1127inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1128bool
1129operator!=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
1130{
1131    return __x.base() != __y.base();
1132}
1133
1134template <class _Iter1, class _Iter2>
1135inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1136bool
1137operator>(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
1138{
1139    return __x.base() > __y.base();
1140}
1141
1142template <class _Iter1, class _Iter2>
1143inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1144bool
1145operator>=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
1146{
1147    return __x.base() >= __y.base();
1148}
1149
1150template <class _Iter1, class _Iter2>
1151inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1152bool
1153operator<=(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
1154{
1155    return __x.base() <= __y.base();
1156}
1157
1158#ifndef _LIBCPP_CXX03_LANG
1159template <class _Iter1, class _Iter2>
1160inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1161auto
1162operator-(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
1163-> decltype(__x.base() - __y.base())
1164{
1165    return __x.base() - __y.base();
1166}
1167#else
1168template <class _Iter1, class _Iter2>
1169inline _LIBCPP_INLINE_VISIBILITY
1170typename move_iterator<_Iter1>::difference_type
1171operator-(const move_iterator<_Iter1>& __x, const move_iterator<_Iter2>& __y)
1172{
1173    return __x.base() - __y.base();
1174}
1175#endif
1176
1177template <class _Iter>
1178inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1179move_iterator<_Iter>
1180operator+(typename move_iterator<_Iter>::difference_type __n, const move_iterator<_Iter>& __x)
1181{
1182    return move_iterator<_Iter>(__x.base() + __n);
1183}
1184
1185template <class _Iter>
1186inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1187move_iterator<_Iter>
1188make_move_iterator(_Iter __i)
1189{
1190    return move_iterator<_Iter>(__i);
1191}
1192
1193// __wrap_iter
1194
1195template <class _Iter> class __wrap_iter;
1196
1197template <class _Iter1, class _Iter2>
1198_LIBCPP_INLINE_VISIBILITY
1199bool
1200operator==(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT_DEBUG;
1201
1202template <class _Iter1, class _Iter2>
1203_LIBCPP_INLINE_VISIBILITY
1204bool
1205operator<(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT_DEBUG;
1206
1207template <class _Iter1, class _Iter2>
1208_LIBCPP_INLINE_VISIBILITY
1209bool
1210operator!=(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT_DEBUG;
1211
1212template <class _Iter1, class _Iter2>
1213_LIBCPP_INLINE_VISIBILITY
1214bool
1215operator>(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT_DEBUG;
1216
1217template <class _Iter1, class _Iter2>
1218_LIBCPP_INLINE_VISIBILITY
1219bool
1220operator>=(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT_DEBUG;
1221
1222template <class _Iter1, class _Iter2>
1223_LIBCPP_INLINE_VISIBILITY
1224bool
1225operator<=(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT_DEBUG;
1226
1227#ifndef _LIBCPP_CXX03_LANG
1228template <class _Iter1, class _Iter2>
1229_LIBCPP_INLINE_VISIBILITY
1230auto
1231operator-(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT_DEBUG
1232-> decltype(__x.base() - __y.base());
1233#else
1234template <class _Iter1, class _Iter2>
1235_LIBCPP_INLINE_VISIBILITY
1236typename __wrap_iter<_Iter1>::difference_type
1237operator-(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT_DEBUG;
1238#endif
1239
1240template <class _Iter>
1241_LIBCPP_INLINE_VISIBILITY
1242__wrap_iter<_Iter>
1243operator+(typename __wrap_iter<_Iter>::difference_type, __wrap_iter<_Iter>) _NOEXCEPT_DEBUG;
1244
1245template <class _Ip, class _Op> _Op _LIBCPP_INLINE_VISIBILITY copy(_Ip, _Ip, _Op);
1246template <class _B1, class _B2> _B2 _LIBCPP_INLINE_VISIBILITY copy_backward(_B1, _B1, _B2);
1247template <class _Ip, class _Op> _Op _LIBCPP_INLINE_VISIBILITY move(_Ip, _Ip, _Op);
1248template <class _B1, class _B2> _B2 _LIBCPP_INLINE_VISIBILITY move_backward(_B1, _B1, _B2);
1249
1250#if _LIBCPP_DEBUG_LEVEL < 2
1251
1252template <class _Tp>
1253_LIBCPP_INLINE_VISIBILITY
1254typename enable_if
1255<
1256    is_trivially_copy_assignable<_Tp>::value,
1257    _Tp*
1258>::type
1259__unwrap_iter(__wrap_iter<_Tp*>);
1260
1261#else
1262
1263template <class _Tp>
1264inline _LIBCPP_INLINE_VISIBILITY
1265typename enable_if
1266<
1267    is_trivially_copy_assignable<_Tp>::value,
1268    __wrap_iter<_Tp*>
1269>::type
1270__unwrap_iter(__wrap_iter<_Tp*> __i);
1271
1272#endif
1273
1274template <class _Iter>
1275class __wrap_iter
1276{
1277public:
1278    typedef _Iter                                                      iterator_type;
1279    typedef typename iterator_traits<iterator_type>::iterator_category iterator_category;
1280    typedef typename iterator_traits<iterator_type>::value_type        value_type;
1281    typedef typename iterator_traits<iterator_type>::difference_type   difference_type;
1282    typedef typename iterator_traits<iterator_type>::pointer           pointer;
1283    typedef typename iterator_traits<iterator_type>::reference         reference;
1284private:
1285    iterator_type __i;
1286public:
1287    _LIBCPP_INLINE_VISIBILITY __wrap_iter() _NOEXCEPT_DEBUG
1288#if _LIBCPP_STD_VER > 11
1289                : __i{}
1290#endif
1291    {
1292#if _LIBCPP_DEBUG_LEVEL >= 2
1293        __get_db()->__insert_i(this);
1294#endif
1295    }
1296    template <class _Up> _LIBCPP_INLINE_VISIBILITY __wrap_iter(const __wrap_iter<_Up>& __u,
1297        typename enable_if<is_convertible<_Up, iterator_type>::value>::type* = 0) _NOEXCEPT_DEBUG
1298        : __i(__u.base())
1299    {
1300#if _LIBCPP_DEBUG_LEVEL >= 2
1301        __get_db()->__iterator_copy(this, &__u);
1302#endif
1303    }
1304#if _LIBCPP_DEBUG_LEVEL >= 2
1305    _LIBCPP_INLINE_VISIBILITY
1306    __wrap_iter(const __wrap_iter& __x)
1307        : __i(__x.base())
1308    {
1309        __get_db()->__iterator_copy(this, &__x);
1310    }
1311    _LIBCPP_INLINE_VISIBILITY
1312    __wrap_iter& operator=(const __wrap_iter& __x)
1313    {
1314        if (this != &__x)
1315        {
1316            __get_db()->__iterator_copy(this, &__x);
1317            __i = __x.__i;
1318        }
1319        return *this;
1320    }
1321    _LIBCPP_INLINE_VISIBILITY
1322    ~__wrap_iter()
1323    {
1324        __get_db()->__erase_i(this);
1325    }
1326#endif
1327    _LIBCPP_INLINE_VISIBILITY reference operator*() const _NOEXCEPT_DEBUG
1328    {
1329#if _LIBCPP_DEBUG_LEVEL >= 2
1330        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
1331                       "Attempted to dereference a non-dereferenceable iterator");
1332#endif
1333        return *__i;
1334    }
1335    _LIBCPP_INLINE_VISIBILITY pointer  operator->() const _NOEXCEPT_DEBUG
1336    {
1337#if _LIBCPP_DEBUG_LEVEL >= 2
1338        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
1339                       "Attempted to dereference a non-dereferenceable iterator");
1340#endif
1341        return (pointer)_VSTD::addressof(*__i);
1342    }
1343    _LIBCPP_INLINE_VISIBILITY __wrap_iter& operator++() _NOEXCEPT_DEBUG
1344    {
1345#if _LIBCPP_DEBUG_LEVEL >= 2
1346        _LIBCPP_ASSERT(__get_const_db()->__dereferenceable(this),
1347                       "Attempted to increment non-incrementable iterator");
1348#endif
1349        ++__i;
1350        return *this;
1351    }
1352    _LIBCPP_INLINE_VISIBILITY __wrap_iter  operator++(int) _NOEXCEPT_DEBUG
1353        {__wrap_iter __tmp(*this); ++(*this); return __tmp;}
1354    _LIBCPP_INLINE_VISIBILITY __wrap_iter& operator--() _NOEXCEPT_DEBUG
1355    {
1356#if _LIBCPP_DEBUG_LEVEL >= 2
1357        _LIBCPP_ASSERT(__get_const_db()->__decrementable(this),
1358                       "Attempted to decrement non-decrementable iterator");
1359#endif
1360        --__i;
1361        return *this;
1362    }
1363    _LIBCPP_INLINE_VISIBILITY __wrap_iter  operator--(int) _NOEXCEPT_DEBUG
1364        {__wrap_iter __tmp(*this); --(*this); return __tmp;}
1365    _LIBCPP_INLINE_VISIBILITY __wrap_iter  operator+ (difference_type __n) const _NOEXCEPT_DEBUG
1366        {__wrap_iter __w(*this); __w += __n; return __w;}
1367    _LIBCPP_INLINE_VISIBILITY __wrap_iter& operator+=(difference_type __n) _NOEXCEPT_DEBUG
1368    {
1369#if _LIBCPP_DEBUG_LEVEL >= 2
1370        _LIBCPP_ASSERT(__get_const_db()->__addable(this, __n),
1371                   "Attempted to add/subtract iterator outside of valid range");
1372#endif
1373        __i += __n;
1374        return *this;
1375    }
1376    _LIBCPP_INLINE_VISIBILITY __wrap_iter  operator- (difference_type __n) const _NOEXCEPT_DEBUG
1377        {return *this + (-__n);}
1378    _LIBCPP_INLINE_VISIBILITY __wrap_iter& operator-=(difference_type __n) _NOEXCEPT_DEBUG
1379        {*this += -__n; return *this;}
1380    _LIBCPP_INLINE_VISIBILITY reference        operator[](difference_type __n) const _NOEXCEPT_DEBUG
1381    {
1382#if _LIBCPP_DEBUG_LEVEL >= 2
1383        _LIBCPP_ASSERT(__get_const_db()->__subscriptable(this, __n),
1384                   "Attempted to subscript iterator outside of valid range");
1385#endif
1386        return __i[__n];
1387    }
1388
1389    _LIBCPP_INLINE_VISIBILITY iterator_type base() const _NOEXCEPT_DEBUG {return __i;}
1390
1391private:
1392#if _LIBCPP_DEBUG_LEVEL >= 2
1393    _LIBCPP_INLINE_VISIBILITY __wrap_iter(const void* __p, iterator_type __x) : __i(__x)
1394    {
1395        __get_db()->__insert_ic(this, __p);
1396    }
1397#else
1398    _LIBCPP_INLINE_VISIBILITY __wrap_iter(iterator_type __x) _NOEXCEPT_DEBUG : __i(__x) {}
1399#endif
1400
1401    template <class _Up> friend class __wrap_iter;
1402    template <class _CharT, class _Traits, class _Alloc> friend class basic_string;
1403    template <class _Tp, class _Alloc> friend class _LIBCPP_TEMPLATE_VIS vector;
1404
1405    template <class _Iter1, class _Iter2>
1406    friend
1407    bool
1408    operator==(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT_DEBUG;
1409
1410    template <class _Iter1, class _Iter2>
1411    friend
1412    bool
1413    operator<(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT_DEBUG;
1414
1415    template <class _Iter1, class _Iter2>
1416    friend
1417    bool
1418    operator!=(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT_DEBUG;
1419
1420    template <class _Iter1, class _Iter2>
1421    friend
1422    bool
1423    operator>(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT_DEBUG;
1424
1425    template <class _Iter1, class _Iter2>
1426    friend
1427    bool
1428    operator>=(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT_DEBUG;
1429
1430    template <class _Iter1, class _Iter2>
1431    friend
1432    bool
1433    operator<=(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT_DEBUG;
1434
1435#ifndef _LIBCPP_CXX03_LANG
1436    template <class _Iter1, class _Iter2>
1437    friend
1438    auto
1439    operator-(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT_DEBUG
1440    -> decltype(__x.base() - __y.base());
1441#else
1442    template <class _Iter1, class _Iter2>
1443    friend
1444    typename __wrap_iter<_Iter1>::difference_type
1445    operator-(const __wrap_iter<_Iter1>&, const __wrap_iter<_Iter2>&) _NOEXCEPT_DEBUG;
1446#endif
1447
1448    template <class _Iter1>
1449    friend
1450    __wrap_iter<_Iter1>
1451    operator+(typename __wrap_iter<_Iter1>::difference_type, __wrap_iter<_Iter1>) _NOEXCEPT_DEBUG;
1452
1453    template <class _Ip, class _Op> friend _Op copy(_Ip, _Ip, _Op);
1454    template <class _B1, class _B2> friend _B2 copy_backward(_B1, _B1, _B2);
1455    template <class _Ip, class _Op> friend _Op move(_Ip, _Ip, _Op);
1456    template <class _B1, class _B2> friend _B2 move_backward(_B1, _B1, _B2);
1457
1458#if _LIBCPP_DEBUG_LEVEL < 2
1459    template <class _Tp>
1460    friend
1461    typename enable_if
1462    <
1463        is_trivially_copy_assignable<_Tp>::value,
1464        _Tp*
1465    >::type
1466    __unwrap_iter(__wrap_iter<_Tp*>);
1467#else
1468  template <class _Tp>
1469  inline _LIBCPP_INLINE_VISIBILITY
1470  typename enable_if
1471  <
1472      is_trivially_copy_assignable<_Tp>::value,
1473      __wrap_iter<_Tp*>
1474  >::type
1475  __unwrap_iter(__wrap_iter<_Tp*> __i);
1476#endif
1477};
1478
1479template <class _Iter1, class _Iter2>
1480inline _LIBCPP_INLINE_VISIBILITY
1481bool
1482operator==(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT_DEBUG
1483{
1484    return __x.base() == __y.base();
1485}
1486
1487template <class _Iter1, class _Iter2>
1488inline _LIBCPP_INLINE_VISIBILITY
1489bool
1490operator<(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT_DEBUG
1491{
1492#if _LIBCPP_DEBUG_LEVEL >= 2
1493    _LIBCPP_ASSERT(__get_const_db()->__less_than_comparable(&__x, &__y),
1494                   "Attempted to compare incomparable iterators");
1495#endif
1496    return __x.base() < __y.base();
1497}
1498
1499template <class _Iter1, class _Iter2>
1500inline _LIBCPP_INLINE_VISIBILITY
1501bool
1502operator!=(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT_DEBUG
1503{
1504    return !(__x == __y);
1505}
1506
1507template <class _Iter1, class _Iter2>
1508inline _LIBCPP_INLINE_VISIBILITY
1509bool
1510operator>(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT_DEBUG
1511{
1512    return __y < __x;
1513}
1514
1515template <class _Iter1, class _Iter2>
1516inline _LIBCPP_INLINE_VISIBILITY
1517bool
1518operator>=(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT_DEBUG
1519{
1520    return !(__x < __y);
1521}
1522
1523template <class _Iter1, class _Iter2>
1524inline _LIBCPP_INLINE_VISIBILITY
1525bool
1526operator<=(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT_DEBUG
1527{
1528    return !(__y < __x);
1529}
1530
1531template <class _Iter1>
1532inline _LIBCPP_INLINE_VISIBILITY
1533bool
1534operator!=(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter1>& __y) _NOEXCEPT_DEBUG
1535{
1536    return !(__x == __y);
1537}
1538
1539template <class _Iter1>
1540inline _LIBCPP_INLINE_VISIBILITY
1541bool
1542operator>(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter1>& __y) _NOEXCEPT_DEBUG
1543{
1544    return __y < __x;
1545}
1546
1547template <class _Iter1>
1548inline _LIBCPP_INLINE_VISIBILITY
1549bool
1550operator>=(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter1>& __y) _NOEXCEPT_DEBUG
1551{
1552    return !(__x < __y);
1553}
1554
1555template <class _Iter1>
1556inline _LIBCPP_INLINE_VISIBILITY
1557bool
1558operator<=(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter1>& __y) _NOEXCEPT_DEBUG
1559{
1560    return !(__y < __x);
1561}
1562
1563#ifndef _LIBCPP_CXX03_LANG
1564template <class _Iter1, class _Iter2>
1565inline _LIBCPP_INLINE_VISIBILITY
1566auto
1567operator-(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT_DEBUG
1568-> decltype(__x.base() - __y.base())
1569{
1570#if _LIBCPP_DEBUG_LEVEL >= 2
1571    _LIBCPP_ASSERT(__get_const_db()->__less_than_comparable(&__x, &__y),
1572                   "Attempted to subtract incompatible iterators");
1573#endif
1574    return __x.base() - __y.base();
1575}
1576#else
1577template <class _Iter1, class _Iter2>
1578inline _LIBCPP_INLINE_VISIBILITY
1579typename __wrap_iter<_Iter1>::difference_type
1580operator-(const __wrap_iter<_Iter1>& __x, const __wrap_iter<_Iter2>& __y) _NOEXCEPT_DEBUG
1581{
1582#if _LIBCPP_DEBUG_LEVEL >= 2
1583    _LIBCPP_ASSERT(__get_const_db()->__less_than_comparable(&__x, &__y),
1584                   "Attempted to subtract incompatible iterators");
1585#endif
1586    return __x.base() - __y.base();
1587}
1588#endif
1589
1590template <class _Iter>
1591inline _LIBCPP_INLINE_VISIBILITY
1592__wrap_iter<_Iter>
1593operator+(typename __wrap_iter<_Iter>::difference_type __n,
1594          __wrap_iter<_Iter> __x) _NOEXCEPT_DEBUG
1595{
1596    __x += __n;
1597    return __x;
1598}
1599
1600template <class _Iter>
1601struct __libcpp_is_trivial_iterator
1602    : public _LIBCPP_BOOL_CONSTANT(is_pointer<_Iter>::value) {};
1603
1604template <class _Iter>
1605struct __libcpp_is_trivial_iterator<move_iterator<_Iter> >
1606    : public _LIBCPP_BOOL_CONSTANT(__libcpp_is_trivial_iterator<_Iter>::value) {};
1607
1608template <class _Iter>
1609struct __libcpp_is_trivial_iterator<reverse_iterator<_Iter> >
1610    : public _LIBCPP_BOOL_CONSTANT(__libcpp_is_trivial_iterator<_Iter>::value) {};
1611
1612template <class _Iter>
1613struct __libcpp_is_trivial_iterator<__wrap_iter<_Iter> >
1614    : public _LIBCPP_BOOL_CONSTANT(__libcpp_is_trivial_iterator<_Iter>::value) {};
1615
1616
1617template <class _Tp, size_t _Np>
1618inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1619_Tp*
1620begin(_Tp (&__array)[_Np])
1621{
1622    return __array;
1623}
1624
1625template <class _Tp, size_t _Np>
1626inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1627_Tp*
1628end(_Tp (&__array)[_Np])
1629{
1630    return __array + _Np;
1631}
1632
1633#if !defined(_LIBCPP_CXX03_LANG)
1634
1635template <class _Cp>
1636inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1637auto
1638begin(_Cp& __c) -> decltype(__c.begin())
1639{
1640    return __c.begin();
1641}
1642
1643template <class _Cp>
1644inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1645auto
1646begin(const _Cp& __c) -> decltype(__c.begin())
1647{
1648    return __c.begin();
1649}
1650
1651template <class _Cp>
1652inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1653auto
1654end(_Cp& __c) -> decltype(__c.end())
1655{
1656    return __c.end();
1657}
1658
1659template <class _Cp>
1660inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1661auto
1662end(const _Cp& __c) -> decltype(__c.end())
1663{
1664    return __c.end();
1665}
1666
1667#if _LIBCPP_STD_VER > 11
1668
1669template <class _Tp, size_t _Np>
1670inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1671reverse_iterator<_Tp*> rbegin(_Tp (&__array)[_Np])
1672{
1673    return reverse_iterator<_Tp*>(__array + _Np);
1674}
1675
1676template <class _Tp, size_t _Np>
1677inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1678reverse_iterator<_Tp*> rend(_Tp (&__array)[_Np])
1679{
1680    return reverse_iterator<_Tp*>(__array);
1681}
1682
1683template <class _Ep>
1684inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1685reverse_iterator<const _Ep*> rbegin(initializer_list<_Ep> __il)
1686{
1687    return reverse_iterator<const _Ep*>(__il.end());
1688}
1689
1690template <class _Ep>
1691inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1692reverse_iterator<const _Ep*> rend(initializer_list<_Ep> __il)
1693{
1694    return reverse_iterator<const _Ep*>(__il.begin());
1695}
1696
1697template <class _Cp>
1698inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1699auto cbegin(const _Cp& __c) -> decltype(_VSTD::begin(__c))
1700{
1701    return _VSTD::begin(__c);
1702}
1703
1704template <class _Cp>
1705inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1706auto cend(const _Cp& __c) -> decltype(_VSTD::end(__c))
1707{
1708    return _VSTD::end(__c);
1709}
1710
1711template <class _Cp>
1712inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1713auto rbegin(_Cp& __c) -> decltype(__c.rbegin())
1714{
1715    return __c.rbegin();
1716}
1717
1718template <class _Cp>
1719inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1720auto rbegin(const _Cp& __c) -> decltype(__c.rbegin())
1721{
1722    return __c.rbegin();
1723}
1724
1725template <class _Cp>
1726inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1727auto rend(_Cp& __c) -> decltype(__c.rend())
1728{
1729    return __c.rend();
1730}
1731
1732template <class _Cp>
1733inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1734auto rend(const _Cp& __c) -> decltype(__c.rend())
1735{
1736    return __c.rend();
1737}
1738
1739template <class _Cp>
1740inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1741auto crbegin(const _Cp& __c) -> decltype(_VSTD::rbegin(__c))
1742{
1743    return _VSTD::rbegin(__c);
1744}
1745
1746template <class _Cp>
1747inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
1748auto crend(const _Cp& __c) -> decltype(_VSTD::rend(__c))
1749{
1750    return _VSTD::rend(__c);
1751}
1752
1753#endif
1754
1755
1756#else  // defined(_LIBCPP_CXX03_LANG)
1757
1758template <class _Cp>
1759inline _LIBCPP_INLINE_VISIBILITY
1760typename _Cp::iterator
1761begin(_Cp& __c)
1762{
1763    return __c.begin();
1764}
1765
1766template <class _Cp>
1767inline _LIBCPP_INLINE_VISIBILITY
1768typename _Cp::const_iterator
1769begin(const _Cp& __c)
1770{
1771    return __c.begin();
1772}
1773
1774template <class _Cp>
1775inline _LIBCPP_INLINE_VISIBILITY
1776typename _Cp::iterator
1777end(_Cp& __c)
1778{
1779    return __c.end();
1780}
1781
1782template <class _Cp>
1783inline _LIBCPP_INLINE_VISIBILITY
1784typename _Cp::const_iterator
1785end(const _Cp& __c)
1786{
1787    return __c.end();
1788}
1789
1790#endif  // !defined(_LIBCPP_CXX03_LANG)
1791
1792#if _LIBCPP_STD_VER > 14
1793template <class _Cont>
1794constexpr auto size(const _Cont& __c) -> decltype(__c.size()) { return __c.size(); }
1795
1796template <class _Tp, size_t _Sz>
1797constexpr size_t size(const _Tp (&)[_Sz]) noexcept { return _Sz; }
1798
1799template <class _Cont>
1800constexpr auto empty(const _Cont& __c) -> decltype(__c.empty()) { return __c.empty(); }
1801
1802template <class _Tp, size_t _Sz>
1803constexpr bool empty(const _Tp (&)[_Sz]) noexcept { return false; }
1804
1805template <class _Ep>
1806constexpr bool empty(initializer_list<_Ep> __il) noexcept { return __il.size() == 0; }
1807
1808template <class _Cont> constexpr
1809auto data(_Cont& __c) -> decltype(__c.data()) { return __c.data(); }
1810
1811template <class _Cont> constexpr
1812auto data(const _Cont& __c) -> decltype(__c.data()) { return __c.data(); }
1813
1814template <class _Tp, size_t _Sz>
1815constexpr _Tp* data(_Tp (&__array)[_Sz]) noexcept { return __array; }
1816
1817template <class _Ep>
1818constexpr const _Ep* data(initializer_list<_Ep> __il) noexcept { return __il.begin(); }
1819#endif
1820
1821
1822_LIBCPP_END_NAMESPACE_STD
1823
1824#endif  // _LIBCPP_ITERATOR
1825