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