utility revision 262801 
1// -*- C++ -*-
2//===-------------------------- utility -----------------------------------===//
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_UTILITY
12#define _LIBCPP_UTILITY
13
14/*
15    utility synopsis
16
17namespace std
18{
19
20template <class T>
21    void
22    swap(T& a, T& b);
23
24namespace rel_ops
25{
26    template<class T> bool operator!=(const T&, const T&);
27    template<class T> bool operator> (const T&, const T&);
28    template<class T> bool operator<=(const T&, const T&);
29    template<class T> bool operator>=(const T&, const T&);
30}
31
32template<class T>
33void
34swap(T& a, T& b) noexcept(is_nothrow_move_constructible<T>::value &&
35                          is_nothrow_move_assignable<T>::value);
36
37template <class T, size_t N>
38void
39swap(T (&a)[N], T (&b)[N]) noexcept(noexcept(swap(*a, *b)));
40
41template <class T> T&& forward(typename remove_reference<T>::type& t) noexcept;  // constexpr in C++14
42template <class T> T&& forward(typename remove_reference<T>::type&& t) noexcept; // constexpr in C++14
43
44template <class T> typename remove_reference<T>::type&& move(T&&) noexcept;      // constexpr in C++14
45
46template <class T>
47    typename conditional
48    <
49        !is_nothrow_move_constructible<T>::value && is_copy_constructible<T>::value,
50        const T&,
51        T&&
52    >::type
53    move_if_noexcept(T& x) noexcept; // constexpr in C++14
54
55template <class T> typename add_rvalue_reference<T>::type declval() noexcept;
56
57template <class T1, class T2>
58struct pair
59{
60    typedef T1 first_type;
61    typedef T2 second_type;
62
63    T1 first;
64    T2 second;
65
66    pair(const pair&) = default;
67    pair(pair&&) = default;
68    constexpr pair();
69    pair(const T1& x, const T2& y);                          // constexpr in C++14
70    template <class U, class V> pair(U&& x, V&& y);          // constexpr in C++14
71    template <class U, class V> pair(const pair<U, V>& p);   // constexpr in C++14
72    template <class U, class V> pair(pair<U, V>&& p);        // constexpr in C++14
73    template <class... Args1, class... Args2>
74        pair(piecewise_construct_t, tuple<Args1...> first_args,
75             tuple<Args2...> second_args);
76
77    template <class U, class V> pair& operator=(const pair<U, V>& p);
78    pair& operator=(pair&& p) noexcept(is_nothrow_move_assignable<T1>::value &&
79                                       is_nothrow_move_assignable<T2>::value);
80    template <class U, class V> pair& operator=(pair<U, V>&& p);
81
82    void swap(pair& p) noexcept(noexcept(swap(first, p.first)) &&
83                                noexcept(swap(second, p.second)));
84};
85
86template <class T1, class T2> bool operator==(const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
87template <class T1, class T2> bool operator!=(const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
88template <class T1, class T2> bool operator< (const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
89template <class T1, class T2> bool operator> (const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
90template <class T1, class T2> bool operator>=(const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
91template <class T1, class T2> bool operator<=(const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
92
93template <class T1, class T2> pair<V1, V2> make_pair(T1&&, T2&&);   // constexpr in C++14
94template <class T1, class T2>
95void
96swap(pair<T1, T2>& x, pair<T1, T2>& y) noexcept(noexcept(x.swap(y)));
97
98struct piecewise_construct_t { };
99constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
100
101template <class T> class tuple_size;
102template <size_t I, class T> class tuple_element;
103
104template <class T1, class T2> struct tuple_size<std::pair<T1, T2> >;
105template <class T1, class T2> struct tuple_element<0, std::pair<T1, T2> >;
106template <class T1, class T2> struct tuple_element<1, std::pair<T1, T2> >;
107
108template<size_t I, class T1, class T2>
109    typename tuple_element<I, std::pair<T1, T2> >::type&
110    get(std::pair<T1, T2>&) noexcept; // constexpr in C++14
111
112template<size_t I, class T1, class T2>
113    const typename const tuple_element<I, std::pair<T1, T2> >::type&
114    get(const std::pair<T1, T2>&) noexcept; // constexpr in C++14
115
116template<size_t I, class T1, class T2>
117    typename tuple_element<I, std::pair<T1, T2> >::type&&
118    get(std::pair<T1, T2>&&) noexcept; // constexpr in C++14
119
120template<class T1, class T2>
121    constexpr T1& get(std::pair<T1, T2>&) noexcept; // C++14
122
123template<size_t I, class T1, class T2>
124    constexpr T1 const& get(std::pair<T1, T2> const &) noexcept; // C++14
125
126template<size_t I, class T1, class T2>
127    constexpr T1&& get(std::pair<T1, T2>&&) noexcept; // C++14
128
129// C++14
130
131template<class T, T... I>
132struct integer_sequence
133{
134    typedef T value_type;
135
136    static constexpr size_t size() noexcept;
137};
138
139template<size_t... I>
140  using index_sequence = integer_sequence<size_t, I...>;
141
142template<class T, T N>
143  using make_integer_sequence = integer_sequence<T, 0, 1, ..., N-1>;
144template<size_t N>
145  using make_index_sequence = make_integer_sequence<size_t, N>;
146
147template<class... T>
148  using index_sequence_for = make_index_sequence<sizeof...(T)>;
149
150template<class T, class U=T> 
151    T exchange(T& obj, U&& new_value);
152}  // std
153
154*/
155
156#include <__config>
157#include <__tuple>
158#include <type_traits>
159
160#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
161#pragma GCC system_header
162#endif
163
164_LIBCPP_BEGIN_NAMESPACE_STD
165
166namespace rel_ops
167{
168
169template<class _Tp>
170inline _LIBCPP_INLINE_VISIBILITY
171bool
172operator!=(const _Tp& __x, const _Tp& __y)
173{
174    return !(__x == __y);
175}
176
177template<class _Tp>
178inline _LIBCPP_INLINE_VISIBILITY
179bool
180operator> (const _Tp& __x, const _Tp& __y)
181{
182    return __y < __x;
183}
184
185template<class _Tp>
186inline _LIBCPP_INLINE_VISIBILITY
187bool
188operator<=(const _Tp& __x, const _Tp& __y)
189{
190    return !(__y < __x);
191}
192
193template<class _Tp>
194inline _LIBCPP_INLINE_VISIBILITY
195bool
196operator>=(const _Tp& __x, const _Tp& __y)
197{
198    return !(__x < __y);
199}
200
201}  // rel_ops
202
203// swap_ranges
204
205template <class _ForwardIterator1, class _ForwardIterator2>
206inline _LIBCPP_INLINE_VISIBILITY
207_ForwardIterator2
208swap_ranges(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2)
209{
210    for(; __first1 != __last1; ++__first1, ++__first2)
211        swap(*__first1, *__first2);
212    return __first2;
213}
214
215template<class _Tp, size_t _Np>
216inline _LIBCPP_INLINE_VISIBILITY
217void
218swap(_Tp (&__a)[_Np], _Tp (&__b)[_Np]) _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value)
219{
220    _VSTD::swap_ranges(__a, __a + _Np, __b);
221}
222
223template <class _Tp>
224inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
225#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
226typename conditional
227<
228    !is_nothrow_move_constructible<_Tp>::value && is_copy_constructible<_Tp>::value,
229    const _Tp&,
230    _Tp&&
231>::type
232#else  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
233const _Tp&
234#endif
235move_if_noexcept(_Tp& __x) _NOEXCEPT
236{
237    return _VSTD::move(__x);
238}
239
240struct _LIBCPP_TYPE_VIS_ONLY piecewise_construct_t { };
241#if defined(_LIBCPP_HAS_NO_CONSTEXPR) || defined(_LIBCPP_BUILDING_UTILITY)
242extern const piecewise_construct_t piecewise_construct;// = piecewise_construct_t();
243#else
244constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
245#endif
246
247template <class _T1, class _T2>
248struct _LIBCPP_TYPE_VIS_ONLY pair
249{
250    typedef _T1 first_type;
251    typedef _T2 second_type;
252
253    _T1 first;
254    _T2 second;
255
256    // pair(const pair&) = default;
257    // pair(pair&&) = default;
258
259    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR pair() : first(), second() {}
260
261    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
262    pair(const _T1& __x, const _T2& __y)
263        : first(__x), second(__y) {}
264
265    template<class _U1, class _U2>
266        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
267        pair(const pair<_U1, _U2>& __p
268#ifndef _LIBCPP_HAS_NO_ADVANCED_SFINAE
269                 ,typename enable_if<is_convertible<const _U1&, _T1>::value &&
270                                    is_convertible<const _U2&, _T2>::value>::type* = 0
271#endif
272                                      )
273            : first(__p.first), second(__p.second) {}
274
275#if !defined(_LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS) && _LIBCPP_TRIVIAL_PAIR_COPY_CTOR
276    _LIBCPP_INLINE_VISIBILITY
277    pair(const pair& __p) = default;
278#elif !defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES) || !_LIBCPP_TRIVIAL_PAIR_COPY_CTOR
279    _LIBCPP_INLINE_VISIBILITY
280    pair(const pair& __p)
281        _NOEXCEPT_(is_nothrow_copy_constructible<first_type>::value &&
282                   is_nothrow_copy_constructible<second_type>::value)
283        : first(__p.first),
284          second(__p.second)
285    {
286    }
287#endif
288
289    _LIBCPP_INLINE_VISIBILITY
290    pair& operator=(const pair& __p)
291        _NOEXCEPT_(is_nothrow_copy_assignable<first_type>::value &&
292                   is_nothrow_copy_assignable<second_type>::value)
293    {
294        first = __p.first;
295        second = __p.second;
296        return *this;
297    }
298
299#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
300
301    template <class _U1, class _U2,
302              class = typename enable_if<is_convertible<_U1, first_type>::value &&
303                                         is_convertible<_U2, second_type>::value>::type>
304        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
305        pair(_U1&& __u1, _U2&& __u2)
306            : first(_VSTD::forward<_U1>(__u1)),
307              second(_VSTD::forward<_U2>(__u2))
308            {}
309
310    template<class _U1, class _U2>
311        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
312        pair(pair<_U1, _U2>&& __p,
313                 typename enable_if<is_convertible<_U1, _T1>::value &&
314                                    is_convertible<_U2, _T2>::value>::type* = 0)
315            : first(_VSTD::forward<_U1>(__p.first)),
316              second(_VSTD::forward<_U2>(__p.second)) {}
317
318#ifndef _LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS
319    _LIBCPP_INLINE_VISIBILITY
320    pair(pair&& __p) = default;
321#else
322    _LIBCPP_INLINE_VISIBILITY
323    pair(pair&& __p) _NOEXCEPT_(is_nothrow_move_constructible<first_type>::value &&
324                                is_nothrow_move_constructible<second_type>::value)
325        : first(_VSTD::forward<first_type>(__p.first)),
326          second(_VSTD::forward<second_type>(__p.second))
327    {
328    }
329#endif
330
331    _LIBCPP_INLINE_VISIBILITY
332    pair&
333    operator=(pair&& __p) _NOEXCEPT_(is_nothrow_move_assignable<first_type>::value &&
334                                     is_nothrow_move_assignable<second_type>::value)
335    {
336        first = _VSTD::forward<first_type>(__p.first);
337        second = _VSTD::forward<second_type>(__p.second);
338        return *this;
339    }
340
341#ifndef _LIBCPP_HAS_NO_VARIADICS
342
343    template<class _Tuple,
344             class = typename enable_if<__tuple_convertible<_Tuple, pair>::value>::type>
345        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
346        pair(_Tuple&& __p)
347            : first(_VSTD::forward<typename tuple_element<0,
348                                  typename __make_tuple_types<_Tuple>::type>::type>(get<0>(__p))),
349              second(_VSTD::forward<typename tuple_element<1,
350                                   typename __make_tuple_types<_Tuple>::type>::type>(get<1>(__p)))
351            {}
352
353
354
355    template <class... _Args1, class... _Args2>
356        _LIBCPP_INLINE_VISIBILITY
357        pair(piecewise_construct_t __pc, tuple<_Args1...> __first_args,
358                                    tuple<_Args2...> __second_args)
359            : pair(__pc, __first_args, __second_args,
360                   typename __make_tuple_indices<sizeof...(_Args1)>::type(),
361                   typename __make_tuple_indices<sizeof...(_Args2) >::type())
362            {}
363
364    template <class _Tuple,
365              class = typename enable_if<__tuple_assignable<_Tuple, pair>::value>::type>
366        _LIBCPP_INLINE_VISIBILITY
367        pair&
368        operator=(_Tuple&& __p)
369        {
370            typedef typename __make_tuple_types<_Tuple>::type _TupleRef;
371            typedef typename tuple_element<0, _TupleRef>::type _U0;
372            typedef typename tuple_element<1, _TupleRef>::type _U1;
373            first  = _VSTD::forward<_U0>(_VSTD::get<0>(__p));
374            second = _VSTD::forward<_U1>(_VSTD::get<1>(__p));
375            return *this;
376        }
377
378#endif  // _LIBCPP_HAS_NO_VARIADICS
379
380#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
381    _LIBCPP_INLINE_VISIBILITY
382    void
383    swap(pair& __p) _NOEXCEPT_(__is_nothrow_swappable<first_type>::value &&
384                               __is_nothrow_swappable<second_type>::value)
385    {
386        _VSTD::iter_swap(&first, &__p.first);
387        _VSTD::iter_swap(&second, &__p.second);
388    }
389private:
390
391#ifndef _LIBCPP_HAS_NO_VARIADICS
392    template <class... _Args1, class... _Args2, size_t... _I1, size_t... _I2>
393        _LIBCPP_INLINE_VISIBILITY
394        pair(piecewise_construct_t,
395             tuple<_Args1...>& __first_args, tuple<_Args2...>& __second_args,
396             __tuple_indices<_I1...>, __tuple_indices<_I2...>);
397#endif  // _LIBCPP_HAS_NO_VARIADICS
398};
399
400template <class _T1, class _T2>
401inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
402bool
403operator==(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
404{
405    return __x.first == __y.first && __x.second == __y.second;
406}
407
408template <class _T1, class _T2>
409inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
410bool
411operator!=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
412{
413    return !(__x == __y);
414}
415
416template <class _T1, class _T2>
417inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
418bool
419operator< (const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
420{
421    return __x.first < __y.first || (!(__y.first < __x.first) && __x.second < __y.second);
422}
423
424template <class _T1, class _T2>
425inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
426bool
427operator> (const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
428{
429    return __y < __x;
430}
431
432template <class _T1, class _T2>
433inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
434bool
435operator>=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
436{
437    return !(__x < __y);
438}
439
440template <class _T1, class _T2>
441inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
442bool
443operator<=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
444{
445    return !(__y < __x);
446}
447
448template <class _T1, class _T2>
449inline _LIBCPP_INLINE_VISIBILITY
450typename enable_if
451<
452    __is_swappable<_T1>::value &&
453    __is_swappable<_T2>::value,
454    void
455>::type
456swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y)
457                     _NOEXCEPT_((__is_nothrow_swappable<_T1>::value &&
458                                 __is_nothrow_swappable<_T2>::value))
459{
460    __x.swap(__y);
461}
462
463#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
464
465template <class _Tp> class _LIBCPP_TYPE_VIS_ONLY reference_wrapper;
466
467template <class _Tp>
468struct ___make_pair_return
469{
470    typedef _Tp type;
471};
472
473template <class _Tp>
474struct ___make_pair_return<reference_wrapper<_Tp>>
475{
476    typedef _Tp& type;
477};
478
479template <class _Tp>
480struct __make_pair_return
481{
482    typedef typename ___make_pair_return<typename decay<_Tp>::type>::type type;
483};
484
485template <class _T1, class _T2>
486inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
487pair<typename __make_pair_return<_T1>::type, typename __make_pair_return<_T2>::type>
488make_pair(_T1&& __t1, _T2&& __t2)
489{
490    return pair<typename __make_pair_return<_T1>::type, typename __make_pair_return<_T2>::type>
491               (_VSTD::forward<_T1>(__t1), _VSTD::forward<_T2>(__t2));
492}
493
494#else  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
495
496template <class _T1, class _T2>
497inline _LIBCPP_INLINE_VISIBILITY
498pair<_T1,_T2>
499make_pair(_T1 __x, _T2 __y)
500{
501    return pair<_T1, _T2>(__x, __y);
502}
503
504#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
505
506template <class _T1, class _T2>
507  class _LIBCPP_TYPE_VIS_ONLY tuple_size<pair<_T1, _T2> >
508    : public integral_constant<size_t, 2> {};
509
510template <class _T1, class _T2>
511  class _LIBCPP_TYPE_VIS_ONLY tuple_size<const pair<_T1, _T2> >
512    : public integral_constant<size_t, 2> {};
513
514template <class _T1, class _T2>
515class _LIBCPP_TYPE_VIS_ONLY tuple_element<0, pair<_T1, _T2> >
516{
517public:
518    typedef _T1 type;
519};
520
521template <class _T1, class _T2>
522class _LIBCPP_TYPE_VIS_ONLY tuple_element<1, pair<_T1, _T2> >
523{
524public:
525    typedef _T2 type;
526};
527
528template <class _T1, class _T2>
529class _LIBCPP_TYPE_VIS_ONLY tuple_element<0, const pair<_T1, _T2> >
530{
531public:
532    typedef const _T1 type;
533};
534
535template <class _T1, class _T2>
536class _LIBCPP_TYPE_VIS_ONLY tuple_element<1, const pair<_T1, _T2> >
537{
538public:
539    typedef const _T2 type;
540};
541
542template <size_t _Ip> struct __get_pair;
543
544template <>
545struct __get_pair<0>
546{
547    template <class _T1, class _T2>
548    static
549    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
550    _T1&
551    get(pair<_T1, _T2>& __p) _NOEXCEPT {return __p.first;}
552
553    template <class _T1, class _T2>
554    static
555    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
556    const _T1&
557    get(const pair<_T1, _T2>& __p) _NOEXCEPT {return __p.first;}
558
559#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
560
561    template <class _T1, class _T2>
562    static
563    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
564    _T1&&
565    get(pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<_T1>(__p.first);}
566
567#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
568};
569
570template <>
571struct __get_pair<1>
572{
573    template <class _T1, class _T2>
574    static
575    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
576    _T2&
577    get(pair<_T1, _T2>& __p) _NOEXCEPT {return __p.second;}
578
579    template <class _T1, class _T2>
580    static
581    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
582    const _T2&
583    get(const pair<_T1, _T2>& __p) _NOEXCEPT {return __p.second;}
584
585#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
586
587    template <class _T1, class _T2>
588    static
589    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
590    _T2&&
591    get(pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<_T2>(__p.second);}
592
593#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
594};
595
596template <size_t _Ip, class _T1, class _T2>
597inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
598typename tuple_element<_Ip, pair<_T1, _T2> >::type&
599get(pair<_T1, _T2>& __p) _NOEXCEPT
600{
601    return __get_pair<_Ip>::get(__p);
602}
603
604template <size_t _Ip, class _T1, class _T2>
605inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
606const typename tuple_element<_Ip, pair<_T1, _T2> >::type&
607get(const pair<_T1, _T2>& __p) _NOEXCEPT
608{
609    return __get_pair<_Ip>::get(__p);
610}
611
612#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
613
614template <size_t _Ip, class _T1, class _T2>
615inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
616typename tuple_element<_Ip, pair<_T1, _T2> >::type&&
617get(pair<_T1, _T2>&& __p) _NOEXCEPT
618{
619    return __get_pair<_Ip>::get(_VSTD::move(__p));
620}
621
622#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
623
624#if _LIBCPP_STD_VER > 11
625template <class _T1, class _T2>
626inline _LIBCPP_INLINE_VISIBILITY
627constexpr _T1 & get(pair<_T1, _T2>& __p) _NOEXCEPT
628{
629    return __get_pair<0>::get(__p);
630}
631
632template <class _T1, class _T2>
633inline _LIBCPP_INLINE_VISIBILITY
634constexpr _T1 const & get(pair<_T1, _T2> const& __p) _NOEXCEPT
635{
636    return __get_pair<0>::get(__p);
637}
638
639template <class _T1, class _T2>
640inline _LIBCPP_INLINE_VISIBILITY
641constexpr _T1 && get(pair<_T1, _T2>&& __p) _NOEXCEPT
642{
643    return __get_pair<0>::get(_VSTD::move(__p));
644}
645
646template <class _T1, class _T2>
647inline _LIBCPP_INLINE_VISIBILITY
648constexpr _T1 & get(pair<_T2, _T1>& __p) _NOEXCEPT
649{
650    return __get_pair<1>::get(__p);
651}
652
653template <class _T1, class _T2>
654inline _LIBCPP_INLINE_VISIBILITY
655constexpr _T1 const & get(pair<_T2, _T1> const& __p) _NOEXCEPT
656{
657    return __get_pair<1>::get(__p);
658}
659
660template <class _T1, class _T2>
661inline _LIBCPP_INLINE_VISIBILITY
662constexpr _T1 && get(pair<_T2, _T1>&& __p) _NOEXCEPT
663{
664    return __get_pair<1>::get(_VSTD::move(__p));
665}
666
667#endif
668
669#if _LIBCPP_STD_VER > 11
670
671template<class _Tp, _Tp... _Ip>
672struct _LIBCPP_TYPE_VIS_ONLY integer_sequence
673{
674    typedef _Tp value_type;
675    static_assert( is_integral<_Tp>::value,
676                  "std::integer_sequence can only be instantiated with an integral type" );
677    static
678    _LIBCPP_INLINE_VISIBILITY
679    constexpr
680    size_t
681    size() noexcept { return sizeof...(_Ip); }
682};
683
684template<size_t... _Ip>
685    using index_sequence = integer_sequence<size_t, _Ip...>;
686
687namespace __detail {
688
689template<typename _Tp, size_t ..._Extra> struct __repeat;
690template<typename _Tp, _Tp ..._Np, size_t ..._Extra> struct __repeat<integer_sequence<_Tp, _Np...>, _Extra...> {
691  typedef integer_sequence<_Tp,
692                           _Np...,
693                           sizeof...(_Np) + _Np...,
694                           2 * sizeof...(_Np) + _Np...,
695                           3 * sizeof...(_Np) + _Np...,
696                           4 * sizeof...(_Np) + _Np...,
697                           5 * sizeof...(_Np) + _Np...,
698                           6 * sizeof...(_Np) + _Np...,
699                           7 * sizeof...(_Np) + _Np...,
700                           _Extra...> type;
701};
702
703template<size_t _Np> struct __parity;
704template<size_t _Np> struct __make : __parity<_Np % 8>::template __pmake<_Np> {};
705
706template<> struct __make<0> { typedef integer_sequence<size_t> type; };
707template<> struct __make<1> { typedef integer_sequence<size_t, 0> type; };
708template<> struct __make<2> { typedef integer_sequence<size_t, 0, 1> type; };
709template<> struct __make<3> { typedef integer_sequence<size_t, 0, 1, 2> type; };
710template<> struct __make<4> { typedef integer_sequence<size_t, 0, 1, 2, 3> type; };
711template<> struct __make<5> { typedef integer_sequence<size_t, 0, 1, 2, 3, 4> type; };
712template<> struct __make<6> { typedef integer_sequence<size_t, 0, 1, 2, 3, 4, 5> type; };
713template<> struct __make<7> { typedef integer_sequence<size_t, 0, 1, 2, 3, 4, 5, 6> type; };
714
715template<> struct __parity<0> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type> {}; };
716template<> struct __parity<1> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 1> {}; };
717template<> struct __parity<2> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 2, _Np - 1> {}; };
718template<> struct __parity<3> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 3, _Np - 2, _Np - 1> {}; };
719template<> struct __parity<4> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
720template<> struct __parity<5> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 5, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
721template<> struct __parity<6> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 6, _Np - 5, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
722template<> struct __parity<7> { template<size_t _Np> struct __pmake : __repeat<typename __make<_Np / 8>::type, _Np - 7, _Np - 6, _Np - 5, _Np - 4, _Np - 3, _Np - 2, _Np - 1> {}; };
723
724template<typename _Tp, typename _Up> struct __convert {
725  template<typename> struct __result;
726  template<_Tp ..._Np> struct __result<integer_sequence<_Tp, _Np...> > { typedef integer_sequence<_Up, _Np...> type; };
727};
728template<typename _Tp> struct __convert<_Tp, _Tp> { template<typename _Up> struct __result { typedef _Up type; }; };
729
730}
731
732template<typename _Tp, _Tp _Np> using __make_integer_sequence_unchecked =
733  typename __detail::__convert<size_t, _Tp>::template __result<typename __detail::__make<_Np>::type>::type;
734
735template <class _Tp, _Tp _Ep>
736struct __make_integer_sequence
737{
738    static_assert(is_integral<_Tp>::value,
739                  "std::make_integer_sequence can only be instantiated with an integral type" );
740    static_assert(0 <= _Ep, "std::make_integer_sequence input shall not be negative");
741    typedef __make_integer_sequence_unchecked<_Tp, _Ep> type;
742};
743
744template<class _Tp, _Tp _Np>
745    using make_integer_sequence = typename __make_integer_sequence<_Tp, _Np>::type;
746
747template<size_t _Np>
748    using make_index_sequence = make_integer_sequence<size_t, _Np>;
749
750template<class... _Tp>
751    using index_sequence_for = make_index_sequence<sizeof...(_Tp)>;
752  
753#endif  // _LIBCPP_STD_VER > 11
754
755#if _LIBCPP_STD_VER > 11
756template<class _T1, class _T2 = _T1>
757inline _LIBCPP_INLINE_VISIBILITY
758_T1 exchange(_T1& __obj, _T2 && __new_value)
759{
760    _T1 __old_value = _VSTD::move(__obj);
761    __obj = _VSTD::forward<_T2>(__new_value);
762    return __old_value;
763}    
764#endif  // _LIBCPP_STD_VER > 11
765
766_LIBCPP_END_NAMESPACE_STD
767
768#endif  // _LIBCPP_UTILITY
769