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
17#include <initializer_list>
18
19namespace std
20{
21
22template <class T>
23    void
24    swap(T& a, T& b);
25
26namespace rel_ops
27{
28    template<class T> bool operator!=(const T&, const T&);
29    template<class T> bool operator> (const T&, const T&);
30    template<class T> bool operator<=(const T&, const T&);
31    template<class T> bool operator>=(const T&, const T&);
32}
33
34template<class T>
35void
36swap(T& a, T& b) noexcept(is_nothrow_move_constructible<T>::value &&
37                          is_nothrow_move_assignable<T>::value);
38
39template <class T, size_t N>
40void
41swap(T (&a)[N], T (&b)[N]) noexcept(noexcept(swap(*a, *b)));
42
43template <class T> T&& forward(typename remove_reference<T>::type& t) noexcept;  // constexpr in C++14
44template <class T> T&& forward(typename remove_reference<T>::type&& t) noexcept; // constexpr in C++14
45
46template <class T> typename remove_reference<T>::type&& move(T&&) noexcept;      // constexpr in C++14
47
48template <class T>
49    typename conditional
50    <
51        !is_nothrow_move_constructible<T>::value && is_copy_constructible<T>::value,
52        const T&,
53        T&&
54    >::type
55    move_if_noexcept(T& x) noexcept; // constexpr in C++14
56
57template <class T> constexpr add_const_t<T>& as_const(T& t) noexcept;      // C++17
58template <class T>                      void as_const(const T&&) = delete; // C++17
59
60template <class T> typename add_rvalue_reference<T>::type declval() noexcept;
61
62template <class T1, class T2>
63struct pair
64{
65    typedef T1 first_type;
66    typedef T2 second_type;
67
68    T1 first;
69    T2 second;
70
71    pair(const pair&) = default;
72    pair(pair&&) = default;
73    constexpr pair();
74    pair(const T1& x, const T2& y);                          // constexpr in C++14
75    template <class U, class V> pair(U&& x, V&& y);          // constexpr in C++14
76    template <class U, class V> pair(const pair<U, V>& p);   // constexpr in C++14
77    template <class U, class V> pair(pair<U, V>&& p);        // constexpr in C++14
78    template <class... Args1, class... Args2>
79        pair(piecewise_construct_t, tuple<Args1...> first_args,
80             tuple<Args2...> second_args);
81
82    template <class U, class V> pair& operator=(const pair<U, V>& p);
83    pair& operator=(pair&& p) noexcept(is_nothrow_move_assignable<T1>::value &&
84                                       is_nothrow_move_assignable<T2>::value);
85    template <class U, class V> pair& operator=(pair<U, V>&& p);
86
87    void swap(pair& p) noexcept(is_nothrow_swappable_v<T1> &&
88                                is_nothrow_swappable_v<T2>);
89};
90
91template <class T1, class T2> bool operator==(const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
92template <class T1, class T2> bool operator!=(const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
93template <class T1, class T2> bool operator< (const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
94template <class T1, class T2> bool operator> (const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
95template <class T1, class T2> bool operator>=(const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
96template <class T1, class T2> bool operator<=(const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
97
98template <class T1, class T2> pair<V1, V2> make_pair(T1&&, T2&&);   // constexpr in C++14
99template <class T1, class T2>
100void
101swap(pair<T1, T2>& x, pair<T1, T2>& y) noexcept(noexcept(x.swap(y)));
102
103struct piecewise_construct_t { };
104inline constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
105
106template <class T> class tuple_size;
107template <size_t I, class T> class tuple_element;
108
109template <class T1, class T2> struct tuple_size<pair<T1, T2> >;
110template <class T1, class T2> struct tuple_element<0, pair<T1, T2> >;
111template <class T1, class T2> struct tuple_element<1, pair<T1, T2> >;
112
113template<size_t I, class T1, class T2>
114    typename tuple_element<I, pair<T1, T2> >::type&
115    get(pair<T1, T2>&) noexcept; // constexpr in C++14
116
117template<size_t I, class T1, class T2>
118    const typename tuple_element<I, pair<T1, T2> >::type&
119    get(const pair<T1, T2>&) noexcept; // constexpr in C++14
120
121template<size_t I, class T1, class T2>
122    typename tuple_element<I, pair<T1, T2> >::type&&
123    get(pair<T1, T2>&&) noexcept; // constexpr in C++14
124
125template<size_t I, class T1, class T2>
126    const typename tuple_element<I, pair<T1, T2> >::type&&
127    get(const pair<T1, T2>&&) noexcept; // constexpr in C++14
128
129template<class T1, class T2>
130    constexpr T1& get(pair<T1, T2>&) noexcept; // C++14
131
132template<class T1, class T2>
133    constexpr const T1& get(const pair<T1, T2>&) noexcept; // C++14
134
135template<class T1, class T2>
136    constexpr T1&& get(pair<T1, T2>&&) noexcept; // C++14
137
138template<class T1, class T2>
139    constexpr const T1&& get(const pair<T1, T2>&&) noexcept; // C++14
140
141template<class T1, class T2>
142    constexpr T1& get(pair<T2, T1>&) noexcept; // C++14
143
144template<class T1, class T2>
145    constexpr const T1& get(const pair<T2, T1>&) noexcept; // C++14
146
147template<class T1, class T2>
148    constexpr T1&& get(pair<T2, T1>&&) noexcept; // C++14
149
150template<class T1, class T2>
151    constexpr const T1&& get(const pair<T2, T1>&&) noexcept; // C++14
152
153// C++14
154
155template<class T, T... I>
156struct integer_sequence
157{
158    typedef T value_type;
159
160    static constexpr size_t size() noexcept;
161};
162
163template<size_t... I>
164  using index_sequence = integer_sequence<size_t, I...>;
165
166template<class T, T N>
167  using make_integer_sequence = integer_sequence<T, 0, 1, ..., N-1>;
168template<size_t N>
169  using make_index_sequence = make_integer_sequence<size_t, N>;
170
171template<class... T>
172  using index_sequence_for = make_index_sequence<sizeof...(T)>;
173
174template<class T, class U=T>
175    T exchange(T& obj, U&& new_value);
176
177// 20.2.7, in-place construction // C++17
178struct in_place_t {
179  explicit in_place_t() = default;
180};
181inline constexpr in_place_t in_place{};
182template <class T>
183  struct in_place_type_t {
184    explicit in_place_type_t() = default;
185  };
186template <class T>
187  inline constexpr in_place_type_t<T> in_place_type{};
188template <size_t I>
189  struct in_place_index_t {
190    explicit in_place_index_t() = default;
191  };
192template <size_t I>
193  inline constexpr in_place_index_t<I> in_place_index{};
194
195}  // std
196
197*/
198
199#include <__config>
200#include <__tuple>
201#include <type_traits>
202#include <initializer_list>
203#include <cstddef>
204#include <cstring>
205#include <cstdint>
206#include <version>
207#include <__debug>
208
209#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
210#pragma GCC system_header
211#endif
212
213_LIBCPP_BEGIN_NAMESPACE_STD
214
215namespace rel_ops
216{
217
218template<class _Tp>
219inline _LIBCPP_INLINE_VISIBILITY
220bool
221operator!=(const _Tp& __x, const _Tp& __y)
222{
223    return !(__x == __y);
224}
225
226template<class _Tp>
227inline _LIBCPP_INLINE_VISIBILITY
228bool
229operator> (const _Tp& __x, const _Tp& __y)
230{
231    return __y < __x;
232}
233
234template<class _Tp>
235inline _LIBCPP_INLINE_VISIBILITY
236bool
237operator<=(const _Tp& __x, const _Tp& __y)
238{
239    return !(__y < __x);
240}
241
242template<class _Tp>
243inline _LIBCPP_INLINE_VISIBILITY
244bool
245operator>=(const _Tp& __x, const _Tp& __y)
246{
247    return !(__x < __y);
248}
249
250}  // rel_ops
251
252// swap_ranges
253
254
255template <class _ForwardIterator1, class _ForwardIterator2>
256inline _LIBCPP_INLINE_VISIBILITY
257_ForwardIterator2
258swap_ranges(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2)
259{
260    for(; __first1 != __last1; ++__first1, (void) ++__first2)
261        swap(*__first1, *__first2);
262    return __first2;
263}
264
265// forward declared in <type_traits>
266template<class _Tp, size_t _Np>
267inline _LIBCPP_INLINE_VISIBILITY
268typename enable_if<
269    __is_swappable<_Tp>::value
270>::type
271swap(_Tp (&__a)[_Np], _Tp (&__b)[_Np]) _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value)
272{
273    _VSTD::swap_ranges(__a, __a + _Np, __b);
274}
275
276template <class _Tp>
277inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
278#ifndef _LIBCPP_CXX03_LANG
279typename conditional
280<
281    !is_nothrow_move_constructible<_Tp>::value && is_copy_constructible<_Tp>::value,
282    const _Tp&,
283    _Tp&&
284>::type
285#else  // _LIBCPP_CXX03_LANG
286const _Tp&
287#endif
288move_if_noexcept(_Tp& __x) _NOEXCEPT
289{
290    return _VSTD::move(__x);
291}
292
293#if _LIBCPP_STD_VER > 14
294template <class _Tp> constexpr add_const_t<_Tp>& as_const(_Tp& __t) noexcept { return __t; }
295template <class _Tp>                        void as_const(const _Tp&&) = delete;
296#endif
297
298struct _LIBCPP_TEMPLATE_VIS piecewise_construct_t { };
299#if defined(_LIBCPP_CXX03_LANG) || defined(_LIBCPP_BUILDING_LIBRARY)
300extern _LIBCPP_EXPORTED_FROM_ABI const piecewise_construct_t piecewise_construct;// = piecewise_construct_t();
301#else
302/* _LIBCPP_INLINE_VAR */ constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
303#endif
304
305#if defined(_LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR)
306struct __non_trivially_copyable_base {
307  _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
308  __non_trivially_copyable_base() _NOEXCEPT {}
309  _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
310  __non_trivially_copyable_base(__non_trivially_copyable_base const&) _NOEXCEPT {}
311};
312#endif
313
314template <class _T1, class _T2>
315struct _LIBCPP_TEMPLATE_VIS pair
316#if defined(_LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR)
317: private __non_trivially_copyable_base
318#endif
319{
320    typedef _T1 first_type;
321    typedef _T2 second_type;
322
323    _T1 first;
324    _T2 second;
325
326#if !defined(_LIBCPP_CXX03_LANG)
327    pair(pair const&) = default;
328    pair(pair&&) = default;
329#else
330  // Use the implicitly declared copy constructor in C++03
331#endif
332
333#ifdef _LIBCPP_CXX03_LANG
334    _LIBCPP_INLINE_VISIBILITY
335    pair() : first(), second() {}
336
337    _LIBCPP_INLINE_VISIBILITY
338    pair(_T1 const& __t1, _T2 const& __t2) : first(__t1), second(__t2) {}
339
340    template <class _U1, class _U2>
341    _LIBCPP_INLINE_VISIBILITY
342    pair(const pair<_U1, _U2>& __p) : first(__p.first), second(__p.second) {}
343
344    _LIBCPP_INLINE_VISIBILITY
345    pair& operator=(pair const& __p) {
346        first = __p.first;
347        second = __p.second;
348        return *this;
349    }
350#else
351    template <bool _Val>
352    using _EnableB = typename enable_if<_Val, bool>::type;
353
354    struct _CheckArgs {
355      template <class _U1, class _U2>
356      static constexpr bool __enable_default() {
357          return is_default_constructible<_U1>::value
358              && is_default_constructible<_U2>::value;
359      }
360
361      template <class _U1, class _U2>
362      static constexpr bool __enable_explicit() {
363          return is_constructible<first_type, _U1>::value
364              && is_constructible<second_type, _U2>::value
365              && (!is_convertible<_U1, first_type>::value
366                  || !is_convertible<_U2, second_type>::value);
367      }
368
369      template <class _U1, class _U2>
370      static constexpr bool __enable_implicit() {
371          return is_constructible<first_type, _U1>::value
372              && is_constructible<second_type, _U2>::value
373              && is_convertible<_U1, first_type>::value
374              && is_convertible<_U2, second_type>::value;
375      }
376    };
377
378    template <bool _MaybeEnable>
379    using _CheckArgsDep = typename conditional<
380      _MaybeEnable, _CheckArgs, __check_tuple_constructor_fail>::type;
381
382    struct _CheckTupleLikeConstructor {
383        template <class _Tuple>
384        static constexpr bool __enable_implicit() {
385            return __tuple_convertible<_Tuple, pair>::value;
386        }
387
388        template <class _Tuple>
389        static constexpr bool __enable_explicit() {
390            return __tuple_constructible<_Tuple, pair>::value
391               && !__tuple_convertible<_Tuple, pair>::value;
392        }
393
394        template <class _Tuple>
395        static constexpr bool __enable_assign() {
396            return __tuple_assignable<_Tuple, pair>::value;
397        }
398    };
399
400    template <class _Tuple>
401    using _CheckTLC = typename conditional<
402        __tuple_like_with_size<_Tuple, 2>::value
403            && !is_same<typename decay<_Tuple>::type, pair>::value,
404        _CheckTupleLikeConstructor,
405        __check_tuple_constructor_fail
406    >::type;
407
408    template<bool _Dummy = true, _EnableB<
409            _CheckArgsDep<_Dummy>::template __enable_default<_T1, _T2>()
410    > = false>
411    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
412    pair() : first(), second() {}
413
414    template <bool _Dummy = true, _EnableB<
415             _CheckArgsDep<_Dummy>::template __enable_explicit<_T1 const&, _T2 const&>()
416    > = false>
417    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
418    explicit pair(_T1 const& __t1, _T2 const& __t2)
419        : first(__t1), second(__t2) {}
420
421    template<bool _Dummy = true, _EnableB<
422            _CheckArgsDep<_Dummy>::template __enable_implicit<_T1 const&, _T2 const&>()
423    > = false>
424    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
425    pair(_T1 const& __t1, _T2 const& __t2)
426        : first(__t1), second(__t2) {}
427
428    template<class _U1, class _U2, _EnableB<
429             _CheckArgs::template __enable_explicit<_U1, _U2>()
430    > = false>
431    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
432    explicit pair(_U1&& __u1, _U2&& __u2)
433        : first(_VSTD::forward<_U1>(__u1)), second(_VSTD::forward<_U2>(__u2)) {}
434
435    template<class _U1, class _U2, _EnableB<
436            _CheckArgs::template __enable_implicit<_U1, _U2>()
437    > = false>
438    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
439    pair(_U1&& __u1, _U2&& __u2)
440        : first(_VSTD::forward<_U1>(__u1)), second(_VSTD::forward<_U2>(__u2)) {}
441
442    template<class _U1, class _U2, _EnableB<
443            _CheckArgs::template __enable_explicit<_U1 const&, _U2 const&>()
444    > = false>
445    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
446    explicit pair(pair<_U1, _U2> const& __p)
447        : first(__p.first), second(__p.second) {}
448
449    template<class _U1, class _U2, _EnableB<
450            _CheckArgs::template __enable_implicit<_U1 const&, _U2 const&>()
451    > = false>
452    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
453    pair(pair<_U1, _U2> const& __p)
454        : first(__p.first), second(__p.second) {}
455
456    template<class _U1, class _U2, _EnableB<
457            _CheckArgs::template __enable_explicit<_U1, _U2>()
458    > = false>
459    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
460    explicit pair(pair<_U1, _U2>&&__p)
461        : first(_VSTD::forward<_U1>(__p.first)), second(_VSTD::forward<_U2>(__p.second)) {}
462
463    template<class _U1, class _U2, _EnableB<
464            _CheckArgs::template __enable_implicit<_U1, _U2>()
465    > = false>
466    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
467    pair(pair<_U1, _U2>&& __p)
468        : first(_VSTD::forward<_U1>(__p.first)), second(_VSTD::forward<_U2>(__p.second)) {}
469
470    template<class _Tuple, _EnableB<
471            _CheckTLC<_Tuple>::template __enable_explicit<_Tuple>()
472    > = false>
473    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
474    explicit pair(_Tuple&& __p)
475        : first(_VSTD::get<0>(_VSTD::forward<_Tuple>(__p))),
476          second(_VSTD::get<1>(_VSTD::forward<_Tuple>(__p))) {}
477
478    template<class _Tuple, _EnableB<
479            _CheckTLC<_Tuple>::template __enable_implicit<_Tuple>()
480    > = false>
481    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
482    pair(_Tuple&& __p)
483        : first(_VSTD::get<0>(_VSTD::forward<_Tuple>(__p))),
484          second(_VSTD::get<1>(_VSTD::forward<_Tuple>(__p))) {}
485
486    template <class... _Args1, class... _Args2>
487    _LIBCPP_INLINE_VISIBILITY
488    pair(piecewise_construct_t __pc,
489         tuple<_Args1...> __first_args, tuple<_Args2...> __second_args)
490        : pair(__pc, __first_args, __second_args,
491                typename __make_tuple_indices<sizeof...(_Args1)>::type(),
492                typename __make_tuple_indices<sizeof...(_Args2) >::type()) {}
493
494    _LIBCPP_INLINE_VISIBILITY
495    pair& operator=(typename conditional<
496                        is_copy_assignable<first_type>::value &&
497                        is_copy_assignable<second_type>::value,
498                    pair, __nat>::type const& __p)
499        _NOEXCEPT_(is_nothrow_copy_assignable<first_type>::value &&
500                   is_nothrow_copy_assignable<second_type>::value)
501    {
502        first = __p.first;
503        second = __p.second;
504        return *this;
505    }
506
507    _LIBCPP_INLINE_VISIBILITY
508    pair& operator=(typename conditional<
509                        is_move_assignable<first_type>::value &&
510                        is_move_assignable<second_type>::value,
511                    pair, __nat>::type&& __p)
512        _NOEXCEPT_(is_nothrow_move_assignable<first_type>::value &&
513                   is_nothrow_move_assignable<second_type>::value)
514    {
515        first = _VSTD::forward<first_type>(__p.first);
516        second = _VSTD::forward<second_type>(__p.second);
517        return *this;
518    }
519
520    template <class _Tuple, _EnableB<
521            _CheckTLC<_Tuple>::template __enable_assign<_Tuple>()
522     > = false>
523    _LIBCPP_INLINE_VISIBILITY
524    pair& operator=(_Tuple&& __p) {
525        first = _VSTD::get<0>(_VSTD::forward<_Tuple>(__p));
526        second = _VSTD::get<1>(_VSTD::forward<_Tuple>(__p));
527        return *this;
528    }
529#endif
530
531    _LIBCPP_INLINE_VISIBILITY
532    void
533    swap(pair& __p) _NOEXCEPT_(__is_nothrow_swappable<first_type>::value &&
534                               __is_nothrow_swappable<second_type>::value)
535    {
536        using _VSTD::swap;
537        swap(first,  __p.first);
538        swap(second, __p.second);
539    }
540private:
541
542#ifndef _LIBCPP_CXX03_LANG
543    template <class... _Args1, class... _Args2, size_t... _I1, size_t... _I2>
544        _LIBCPP_INLINE_VISIBILITY
545        pair(piecewise_construct_t,
546             tuple<_Args1...>& __first_args, tuple<_Args2...>& __second_args,
547             __tuple_indices<_I1...>, __tuple_indices<_I2...>);
548#endif
549};
550
551#ifndef _LIBCPP_HAS_NO_DEDUCTION_GUIDES
552template<class _T1, class _T2>
553pair(_T1, _T2) -> pair<_T1, _T2>;
554#endif // _LIBCPP_HAS_NO_DEDUCTION_GUIDES
555
556template <class _T1, class _T2>
557inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
558bool
559operator==(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
560{
561    return __x.first == __y.first && __x.second == __y.second;
562}
563
564template <class _T1, class _T2>
565inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
566bool
567operator!=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
568{
569    return !(__x == __y);
570}
571
572template <class _T1, class _T2>
573inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
574bool
575operator< (const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
576{
577    return __x.first < __y.first || (!(__y.first < __x.first) && __x.second < __y.second);
578}
579
580template <class _T1, class _T2>
581inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
582bool
583operator> (const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
584{
585    return __y < __x;
586}
587
588template <class _T1, class _T2>
589inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
590bool
591operator>=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
592{
593    return !(__x < __y);
594}
595
596template <class _T1, class _T2>
597inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
598bool
599operator<=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
600{
601    return !(__y < __x);
602}
603
604template <class _T1, class _T2>
605inline _LIBCPP_INLINE_VISIBILITY
606typename enable_if
607<
608    __is_swappable<_T1>::value &&
609    __is_swappable<_T2>::value,
610    void
611>::type
612swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y)
613                     _NOEXCEPT_((__is_nothrow_swappable<_T1>::value &&
614                                 __is_nothrow_swappable<_T2>::value))
615{
616    __x.swap(__y);
617}
618
619template <class _Tp>
620struct __unwrap_reference { typedef _Tp type; };
621
622template <class _Tp>
623struct __unwrap_reference<reference_wrapper<_Tp> > { typedef _Tp& type; };
624
625#if _LIBCPP_STD_VER > 17
626template <class _Tp>
627struct unwrap_reference : __unwrap_reference<_Tp> { };
628
629template <class _Tp>
630struct unwrap_ref_decay : unwrap_reference<typename decay<_Tp>::type> { };
631#endif // > C++17
632
633template <class _Tp>
634struct __unwrap_ref_decay
635#if _LIBCPP_STD_VER > 17
636    : unwrap_ref_decay<_Tp>
637#else
638    : __unwrap_reference<typename decay<_Tp>::type>
639#endif
640{ };
641
642#ifndef _LIBCPP_CXX03_LANG
643
644template <class _T1, class _T2>
645inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
646pair<typename __unwrap_ref_decay<_T1>::type, typename __unwrap_ref_decay<_T2>::type>
647make_pair(_T1&& __t1, _T2&& __t2)
648{
649    return pair<typename __unwrap_ref_decay<_T1>::type, typename __unwrap_ref_decay<_T2>::type>
650               (_VSTD::forward<_T1>(__t1), _VSTD::forward<_T2>(__t2));
651}
652
653#else  // _LIBCPP_CXX03_LANG
654
655template <class _T1, class _T2>
656inline _LIBCPP_INLINE_VISIBILITY
657pair<_T1,_T2>
658make_pair(_T1 __x, _T2 __y)
659{
660    return pair<_T1, _T2>(__x, __y);
661}
662
663#endif  // _LIBCPP_CXX03_LANG
664
665template <class _T1, class _T2>
666  class _LIBCPP_TEMPLATE_VIS tuple_size<pair<_T1, _T2> >
667    : public integral_constant<size_t, 2> {};
668
669template <size_t _Ip, class _T1, class _T2>
670class _LIBCPP_TEMPLATE_VIS tuple_element<_Ip, pair<_T1, _T2> >
671{
672    static_assert(_Ip < 2, "Index out of bounds in std::tuple_element<std::pair<T1, T2>>");
673};
674
675template <class _T1, class _T2>
676class _LIBCPP_TEMPLATE_VIS tuple_element<0, pair<_T1, _T2> >
677{
678public:
679    typedef _T1 type;
680};
681
682template <class _T1, class _T2>
683class _LIBCPP_TEMPLATE_VIS tuple_element<1, pair<_T1, _T2> >
684{
685public:
686    typedef _T2 type;
687};
688
689template <size_t _Ip> struct __get_pair;
690
691template <>
692struct __get_pair<0>
693{
694    template <class _T1, class _T2>
695    static
696    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
697    _T1&
698    get(pair<_T1, _T2>& __p) _NOEXCEPT {return __p.first;}
699
700    template <class _T1, class _T2>
701    static
702    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
703    const _T1&
704    get(const pair<_T1, _T2>& __p) _NOEXCEPT {return __p.first;}
705
706#ifndef _LIBCPP_CXX03_LANG
707    template <class _T1, class _T2>
708    static
709    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
710    _T1&&
711    get(pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<_T1>(__p.first);}
712
713    template <class _T1, class _T2>
714    static
715    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
716    const _T1&&
717    get(const pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<const _T1>(__p.first);}
718#endif  // _LIBCPP_CXX03_LANG
719};
720
721template <>
722struct __get_pair<1>
723{
724    template <class _T1, class _T2>
725    static
726    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
727    _T2&
728    get(pair<_T1, _T2>& __p) _NOEXCEPT {return __p.second;}
729
730    template <class _T1, class _T2>
731    static
732    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
733    const _T2&
734    get(const pair<_T1, _T2>& __p) _NOEXCEPT {return __p.second;}
735
736#ifndef _LIBCPP_CXX03_LANG
737    template <class _T1, class _T2>
738    static
739    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
740    _T2&&
741    get(pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<_T2>(__p.second);}
742
743    template <class _T1, class _T2>
744    static
745    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
746    const _T2&&
747    get(const pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<const _T2>(__p.second);}
748#endif  // _LIBCPP_CXX03_LANG
749};
750
751template <size_t _Ip, class _T1, class _T2>
752inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
753typename tuple_element<_Ip, pair<_T1, _T2> >::type&
754get(pair<_T1, _T2>& __p) _NOEXCEPT
755{
756    return __get_pair<_Ip>::get(__p);
757}
758
759template <size_t _Ip, class _T1, class _T2>
760inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
761const typename tuple_element<_Ip, pair<_T1, _T2> >::type&
762get(const pair<_T1, _T2>& __p) _NOEXCEPT
763{
764    return __get_pair<_Ip>::get(__p);
765}
766
767#ifndef _LIBCPP_CXX03_LANG
768template <size_t _Ip, class _T1, class _T2>
769inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
770typename tuple_element<_Ip, pair<_T1, _T2> >::type&&
771get(pair<_T1, _T2>&& __p) _NOEXCEPT
772{
773    return __get_pair<_Ip>::get(_VSTD::move(__p));
774}
775
776template <size_t _Ip, class _T1, class _T2>
777inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
778const typename tuple_element<_Ip, pair<_T1, _T2> >::type&&
779get(const pair<_T1, _T2>&& __p) _NOEXCEPT
780{
781    return __get_pair<_Ip>::get(_VSTD::move(__p));
782}
783#endif  // _LIBCPP_CXX03_LANG
784
785#if _LIBCPP_STD_VER > 11
786template <class _T1, class _T2>
787inline _LIBCPP_INLINE_VISIBILITY
788constexpr _T1 & get(pair<_T1, _T2>& __p) _NOEXCEPT
789{
790    return __get_pair<0>::get(__p);
791}
792
793template <class _T1, class _T2>
794inline _LIBCPP_INLINE_VISIBILITY
795constexpr _T1 const & get(pair<_T1, _T2> const& __p) _NOEXCEPT
796{
797    return __get_pair<0>::get(__p);
798}
799
800template <class _T1, class _T2>
801inline _LIBCPP_INLINE_VISIBILITY
802constexpr _T1 && get(pair<_T1, _T2>&& __p) _NOEXCEPT
803{
804    return __get_pair<0>::get(_VSTD::move(__p));
805}
806
807template <class _T1, class _T2>
808inline _LIBCPP_INLINE_VISIBILITY
809constexpr _T1 const && get(pair<_T1, _T2> const&& __p) _NOEXCEPT
810{
811    return __get_pair<0>::get(_VSTD::move(__p));
812}
813
814template <class _T1, class _T2>
815inline _LIBCPP_INLINE_VISIBILITY
816constexpr _T1 & get(pair<_T2, _T1>& __p) _NOEXCEPT
817{
818    return __get_pair<1>::get(__p);
819}
820
821template <class _T1, class _T2>
822inline _LIBCPP_INLINE_VISIBILITY
823constexpr _T1 const & get(pair<_T2, _T1> const& __p) _NOEXCEPT
824{
825    return __get_pair<1>::get(__p);
826}
827
828template <class _T1, class _T2>
829inline _LIBCPP_INLINE_VISIBILITY
830constexpr _T1 && get(pair<_T2, _T1>&& __p) _NOEXCEPT
831{
832    return __get_pair<1>::get(_VSTD::move(__p));
833}
834
835template <class _T1, class _T2>
836inline _LIBCPP_INLINE_VISIBILITY
837constexpr _T1 const && get(pair<_T2, _T1> const&& __p) _NOEXCEPT
838{
839    return __get_pair<1>::get(_VSTD::move(__p));
840}
841
842#endif
843
844#if _LIBCPP_STD_VER > 11
845
846template<class _Tp, _Tp... _Ip>
847struct _LIBCPP_TEMPLATE_VIS integer_sequence
848{
849    typedef _Tp value_type;
850    static_assert( is_integral<_Tp>::value,
851                  "std::integer_sequence can only be instantiated with an integral type" );
852    static
853    _LIBCPP_INLINE_VISIBILITY
854    constexpr
855    size_t
856    size() noexcept { return sizeof...(_Ip); }
857};
858
859template<size_t... _Ip>
860    using index_sequence = integer_sequence<size_t, _Ip...>;
861
862#if __has_builtin(__make_integer_seq) && !defined(_LIBCPP_TESTING_FALLBACK_MAKE_INTEGER_SEQUENCE)
863
864template <class _Tp, _Tp _Ep>
865using __make_integer_sequence = __make_integer_seq<integer_sequence, _Tp, _Ep>;
866
867#else
868
869template<typename _Tp, _Tp _Np> using __make_integer_sequence_unchecked =
870  typename __detail::__make<_Np>::type::template __convert<integer_sequence, _Tp>;
871
872template <class _Tp, _Tp _Ep>
873struct __make_integer_sequence_checked
874{
875    static_assert(is_integral<_Tp>::value,
876                  "std::make_integer_sequence can only be instantiated with an integral type" );
877    static_assert(0 <= _Ep, "std::make_integer_sequence must have a non-negative sequence length");
878    // Workaround GCC bug by preventing bad installations when 0 <= _Ep
879    // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68929
880    typedef __make_integer_sequence_unchecked<_Tp, 0 <= _Ep ? _Ep : 0> type;
881};
882
883template <class _Tp, _Tp _Ep>
884using __make_integer_sequence = typename __make_integer_sequence_checked<_Tp, _Ep>::type;
885
886#endif
887
888template<class _Tp, _Tp _Np>
889    using make_integer_sequence = __make_integer_sequence<_Tp, _Np>;
890
891template<size_t _Np>
892    using make_index_sequence = make_integer_sequence<size_t, _Np>;
893
894template<class... _Tp>
895    using index_sequence_for = make_index_sequence<sizeof...(_Tp)>;
896
897#endif  // _LIBCPP_STD_VER > 11
898
899#if _LIBCPP_STD_VER > 11
900template<class _T1, class _T2 = _T1>
901inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
902_T1 exchange(_T1& __obj, _T2 && __new_value)
903{
904    _T1 __old_value = _VSTD::move(__obj);
905    __obj = _VSTD::forward<_T2>(__new_value);
906    return __old_value;
907}
908#endif  // _LIBCPP_STD_VER > 11
909
910#if _LIBCPP_STD_VER > 14
911
912struct _LIBCPP_TYPE_VIS in_place_t {
913    explicit in_place_t() = default;
914};
915_LIBCPP_INLINE_VAR constexpr in_place_t in_place{};
916
917template <class _Tp>
918struct _LIBCPP_TEMPLATE_VIS in_place_type_t {
919    explicit in_place_type_t() = default;
920};
921template <class _Tp>
922_LIBCPP_INLINE_VAR constexpr in_place_type_t<_Tp> in_place_type{};
923
924template <size_t _Idx>
925struct _LIBCPP_TYPE_VIS in_place_index_t {
926    explicit in_place_index_t() = default;
927};
928template <size_t _Idx>
929_LIBCPP_INLINE_VAR constexpr in_place_index_t<_Idx> in_place_index{};
930
931template <class _Tp> struct __is_inplace_type_imp : false_type {};
932template <class _Tp> struct __is_inplace_type_imp<in_place_type_t<_Tp>> : true_type {};
933
934template <class _Tp>
935using __is_inplace_type = __is_inplace_type_imp<__uncvref_t<_Tp>>;
936
937template <class _Tp> struct __is_inplace_index_imp : false_type {};
938template <size_t _Idx> struct __is_inplace_index_imp<in_place_index_t<_Idx>> : true_type {};
939
940template <class _Tp>
941using __is_inplace_index = __is_inplace_index_imp<__uncvref_t<_Tp>>;
942
943#endif // _LIBCPP_STD_VER > 14
944
945template <class _Arg, class _Result>
946struct _LIBCPP_TEMPLATE_VIS unary_function
947{
948    typedef _Arg    argument_type;
949    typedef _Result result_type;
950};
951
952template <class _Size>
953inline _LIBCPP_INLINE_VISIBILITY
954_Size
955__loadword(const void* __p)
956{
957    _Size __r;
958    std::memcpy(&__r, __p, sizeof(__r));
959    return __r;
960}
961
962// We use murmur2 when size_t is 32 bits, and cityhash64 when size_t
963// is 64 bits.  This is because cityhash64 uses 64bit x 64bit
964// multiplication, which can be very slow on 32-bit systems.
965template <class _Size, size_t = sizeof(_Size)*__CHAR_BIT__>
966struct __murmur2_or_cityhash;
967
968template <class _Size>
969struct __murmur2_or_cityhash<_Size, 32>
970{
971    inline _Size operator()(const void* __key, _Size __len)
972         _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK;
973};
974
975// murmur2
976template <class _Size>
977_Size
978__murmur2_or_cityhash<_Size, 32>::operator()(const void* __key, _Size __len)
979{
980    const _Size __m = 0x5bd1e995;
981    const _Size __r = 24;
982    _Size __h = __len;
983    const unsigned char* __data = static_cast<const unsigned char*>(__key);
984    for (; __len >= 4; __data += 4, __len -= 4)
985    {
986        _Size __k = __loadword<_Size>(__data);
987        __k *= __m;
988        __k ^= __k >> __r;
989        __k *= __m;
990        __h *= __m;
991        __h ^= __k;
992    }
993    switch (__len)
994    {
995    case 3:
996        __h ^= __data[2] << 16;
997        _LIBCPP_FALLTHROUGH();
998    case 2:
999        __h ^= __data[1] << 8;
1000        _LIBCPP_FALLTHROUGH();
1001    case 1:
1002        __h ^= __data[0];
1003        __h *= __m;
1004    }
1005    __h ^= __h >> 13;
1006    __h *= __m;
1007    __h ^= __h >> 15;
1008    return __h;
1009}
1010
1011template <class _Size>
1012struct __murmur2_or_cityhash<_Size, 64>
1013{
1014    inline _Size operator()(const void* __key, _Size __len)  _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK;
1015
1016 private:
1017  // Some primes between 2^63 and 2^64.
1018  static const _Size __k0 = 0xc3a5c85c97cb3127ULL;
1019  static const _Size __k1 = 0xb492b66fbe98f273ULL;
1020  static const _Size __k2 = 0x9ae16a3b2f90404fULL;
1021  static const _Size __k3 = 0xc949d7c7509e6557ULL;
1022
1023  static _Size __rotate(_Size __val, int __shift) {
1024    return __shift == 0 ? __val : ((__val >> __shift) | (__val << (64 - __shift)));
1025  }
1026
1027  static _Size __rotate_by_at_least_1(_Size __val, int __shift) {
1028    return (__val >> __shift) | (__val << (64 - __shift));
1029  }
1030
1031  static _Size __shift_mix(_Size __val) {
1032    return __val ^ (__val >> 47);
1033  }
1034
1035  static _Size __hash_len_16(_Size __u, _Size __v)
1036     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1037  {
1038    const _Size __mul = 0x9ddfea08eb382d69ULL;
1039    _Size __a = (__u ^ __v) * __mul;
1040    __a ^= (__a >> 47);
1041    _Size __b = (__v ^ __a) * __mul;
1042    __b ^= (__b >> 47);
1043    __b *= __mul;
1044    return __b;
1045  }
1046
1047  static _Size __hash_len_0_to_16(const char* __s, _Size __len)
1048     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1049  {
1050    if (__len > 8) {
1051      const _Size __a = __loadword<_Size>(__s);
1052      const _Size __b = __loadword<_Size>(__s + __len - 8);
1053      return __hash_len_16(__a, __rotate_by_at_least_1(__b + __len, __len)) ^ __b;
1054    }
1055    if (__len >= 4) {
1056      const uint32_t __a = __loadword<uint32_t>(__s);
1057      const uint32_t __b = __loadword<uint32_t>(__s + __len - 4);
1058      return __hash_len_16(__len + (__a << 3), __b);
1059    }
1060    if (__len > 0) {
1061      const unsigned char __a = __s[0];
1062      const unsigned char __b = __s[__len >> 1];
1063      const unsigned char __c = __s[__len - 1];
1064      const uint32_t __y = static_cast<uint32_t>(__a) +
1065                           (static_cast<uint32_t>(__b) << 8);
1066      const uint32_t __z = __len + (static_cast<uint32_t>(__c) << 2);
1067      return __shift_mix(__y * __k2 ^ __z * __k3) * __k2;
1068    }
1069    return __k2;
1070  }
1071
1072  static _Size __hash_len_17_to_32(const char *__s, _Size __len)
1073     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1074  {
1075    const _Size __a = __loadword<_Size>(__s) * __k1;
1076    const _Size __b = __loadword<_Size>(__s + 8);
1077    const _Size __c = __loadword<_Size>(__s + __len - 8) * __k2;
1078    const _Size __d = __loadword<_Size>(__s + __len - 16) * __k0;
1079    return __hash_len_16(__rotate(__a - __b, 43) + __rotate(__c, 30) + __d,
1080                         __a + __rotate(__b ^ __k3, 20) - __c + __len);
1081  }
1082
1083  // Return a 16-byte hash for 48 bytes.  Quick and dirty.
1084  // Callers do best to use "random-looking" values for a and b.
1085  static pair<_Size, _Size> __weak_hash_len_32_with_seeds(
1086      _Size __w, _Size __x, _Size __y, _Size __z, _Size __a, _Size __b)
1087        _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1088  {
1089    __a += __w;
1090    __b = __rotate(__b + __a + __z, 21);
1091    const _Size __c = __a;
1092    __a += __x;
1093    __a += __y;
1094    __b += __rotate(__a, 44);
1095    return pair<_Size, _Size>(__a + __z, __b + __c);
1096  }
1097
1098  // Return a 16-byte hash for s[0] ... s[31], a, and b.  Quick and dirty.
1099  static pair<_Size, _Size> __weak_hash_len_32_with_seeds(
1100      const char* __s, _Size __a, _Size __b)
1101    _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1102  {
1103    return __weak_hash_len_32_with_seeds(__loadword<_Size>(__s),
1104                                         __loadword<_Size>(__s + 8),
1105                                         __loadword<_Size>(__s + 16),
1106                                         __loadword<_Size>(__s + 24),
1107                                         __a,
1108                                         __b);
1109  }
1110
1111  // Return an 8-byte hash for 33 to 64 bytes.
1112  static _Size __hash_len_33_to_64(const char *__s, size_t __len)
1113    _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1114  {
1115    _Size __z = __loadword<_Size>(__s + 24);
1116    _Size __a = __loadword<_Size>(__s) +
1117                (__len + __loadword<_Size>(__s + __len - 16)) * __k0;
1118    _Size __b = __rotate(__a + __z, 52);
1119    _Size __c = __rotate(__a, 37);
1120    __a += __loadword<_Size>(__s + 8);
1121    __c += __rotate(__a, 7);
1122    __a += __loadword<_Size>(__s + 16);
1123    _Size __vf = __a + __z;
1124    _Size __vs = __b + __rotate(__a, 31) + __c;
1125    __a = __loadword<_Size>(__s + 16) + __loadword<_Size>(__s + __len - 32);
1126    __z += __loadword<_Size>(__s + __len - 8);
1127    __b = __rotate(__a + __z, 52);
1128    __c = __rotate(__a, 37);
1129    __a += __loadword<_Size>(__s + __len - 24);
1130    __c += __rotate(__a, 7);
1131    __a += __loadword<_Size>(__s + __len - 16);
1132    _Size __wf = __a + __z;
1133    _Size __ws = __b + __rotate(__a, 31) + __c;
1134    _Size __r = __shift_mix((__vf + __ws) * __k2 + (__wf + __vs) * __k0);
1135    return __shift_mix(__r * __k0 + __vs) * __k2;
1136  }
1137};
1138
1139// cityhash64
1140template <class _Size>
1141_Size
1142__murmur2_or_cityhash<_Size, 64>::operator()(const void* __key, _Size __len)
1143{
1144  const char* __s = static_cast<const char*>(__key);
1145  if (__len <= 32) {
1146    if (__len <= 16) {
1147      return __hash_len_0_to_16(__s, __len);
1148    } else {
1149      return __hash_len_17_to_32(__s, __len);
1150    }
1151  } else if (__len <= 64) {
1152    return __hash_len_33_to_64(__s, __len);
1153  }
1154
1155  // For strings over 64 bytes we hash the end first, and then as we
1156  // loop we keep 56 bytes of state: v, w, x, y, and z.
1157  _Size __x = __loadword<_Size>(__s + __len - 40);
1158  _Size __y = __loadword<_Size>(__s + __len - 16) +
1159              __loadword<_Size>(__s + __len - 56);
1160  _Size __z = __hash_len_16(__loadword<_Size>(__s + __len - 48) + __len,
1161                          __loadword<_Size>(__s + __len - 24));
1162  pair<_Size, _Size> __v = __weak_hash_len_32_with_seeds(__s + __len - 64, __len, __z);
1163  pair<_Size, _Size> __w = __weak_hash_len_32_with_seeds(__s + __len - 32, __y + __k1, __x);
1164  __x = __x * __k1 + __loadword<_Size>(__s);
1165
1166  // Decrease len to the nearest multiple of 64, and operate on 64-byte chunks.
1167  __len = (__len - 1) & ~static_cast<_Size>(63);
1168  do {
1169    __x = __rotate(__x + __y + __v.first + __loadword<_Size>(__s + 8), 37) * __k1;
1170    __y = __rotate(__y + __v.second + __loadword<_Size>(__s + 48), 42) * __k1;
1171    __x ^= __w.second;
1172    __y += __v.first + __loadword<_Size>(__s + 40);
1173    __z = __rotate(__z + __w.first, 33) * __k1;
1174    __v = __weak_hash_len_32_with_seeds(__s, __v.second * __k1, __x + __w.first);
1175    __w = __weak_hash_len_32_with_seeds(__s + 32, __z + __w.second,
1176                                        __y + __loadword<_Size>(__s + 16));
1177    std::swap(__z, __x);
1178    __s += 64;
1179    __len -= 64;
1180  } while (__len != 0);
1181  return __hash_len_16(
1182      __hash_len_16(__v.first, __w.first) + __shift_mix(__y) * __k1 + __z,
1183      __hash_len_16(__v.second, __w.second) + __x);
1184}
1185
1186template <class _Tp, size_t = sizeof(_Tp) / sizeof(size_t)>
1187struct __scalar_hash;
1188
1189template <class _Tp>
1190struct __scalar_hash<_Tp, 0>
1191    : public unary_function<_Tp, size_t>
1192{
1193    _LIBCPP_INLINE_VISIBILITY
1194    size_t operator()(_Tp __v) const _NOEXCEPT
1195    {
1196        union
1197        {
1198            _Tp    __t;
1199            size_t __a;
1200        } __u;
1201        __u.__a = 0;
1202        __u.__t = __v;
1203        return __u.__a;
1204    }
1205};
1206
1207template <class _Tp>
1208struct __scalar_hash<_Tp, 1>
1209    : public unary_function<_Tp, size_t>
1210{
1211    _LIBCPP_INLINE_VISIBILITY
1212    size_t operator()(_Tp __v) const _NOEXCEPT
1213    {
1214        union
1215        {
1216            _Tp    __t;
1217            size_t __a;
1218        } __u;
1219        __u.__t = __v;
1220        return __u.__a;
1221    }
1222};
1223
1224template <class _Tp>
1225struct __scalar_hash<_Tp, 2>
1226    : public unary_function<_Tp, size_t>
1227{
1228    _LIBCPP_INLINE_VISIBILITY
1229    size_t operator()(_Tp __v) const _NOEXCEPT
1230    {
1231        union
1232        {
1233            _Tp __t;
1234            struct
1235            {
1236                size_t __a;
1237                size_t __b;
1238            } __s;
1239        } __u;
1240        __u.__t = __v;
1241        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
1242    }
1243};
1244
1245template <class _Tp>
1246struct __scalar_hash<_Tp, 3>
1247    : public unary_function<_Tp, size_t>
1248{
1249    _LIBCPP_INLINE_VISIBILITY
1250    size_t operator()(_Tp __v) const _NOEXCEPT
1251    {
1252        union
1253        {
1254            _Tp __t;
1255            struct
1256            {
1257                size_t __a;
1258                size_t __b;
1259                size_t __c;
1260            } __s;
1261        } __u;
1262        __u.__t = __v;
1263        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
1264    }
1265};
1266
1267template <class _Tp>
1268struct __scalar_hash<_Tp, 4>
1269    : public unary_function<_Tp, size_t>
1270{
1271    _LIBCPP_INLINE_VISIBILITY
1272    size_t operator()(_Tp __v) const _NOEXCEPT
1273    {
1274        union
1275        {
1276            _Tp __t;
1277            struct
1278            {
1279                size_t __a;
1280                size_t __b;
1281                size_t __c;
1282                size_t __d;
1283            } __s;
1284        } __u;
1285        __u.__t = __v;
1286        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
1287    }
1288};
1289
1290struct _PairT {
1291  size_t first;
1292  size_t second;
1293};
1294
1295_LIBCPP_INLINE_VISIBILITY
1296inline size_t __hash_combine(size_t __lhs, size_t __rhs) _NOEXCEPT {
1297    typedef __scalar_hash<_PairT> _HashT;
1298    const _PairT __p = {__lhs, __rhs};
1299    return _HashT()(__p);
1300}
1301
1302template<class _Tp>
1303struct _LIBCPP_TEMPLATE_VIS hash<_Tp*>
1304    : public unary_function<_Tp*, size_t>
1305{
1306    _LIBCPP_INLINE_VISIBILITY
1307    size_t operator()(_Tp* __v) const _NOEXCEPT
1308    {
1309        union
1310        {
1311            _Tp* __t;
1312            size_t __a;
1313        } __u;
1314        __u.__t = __v;
1315        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
1316    }
1317};
1318
1319
1320template <>
1321struct _LIBCPP_TEMPLATE_VIS hash<bool>
1322    : public unary_function<bool, size_t>
1323{
1324    _LIBCPP_INLINE_VISIBILITY
1325    size_t operator()(bool __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1326};
1327
1328template <>
1329struct _LIBCPP_TEMPLATE_VIS hash<char>
1330    : public unary_function<char, size_t>
1331{
1332    _LIBCPP_INLINE_VISIBILITY
1333    size_t operator()(char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1334};
1335
1336template <>
1337struct _LIBCPP_TEMPLATE_VIS hash<signed char>
1338    : public unary_function<signed char, size_t>
1339{
1340    _LIBCPP_INLINE_VISIBILITY
1341    size_t operator()(signed char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1342};
1343
1344template <>
1345struct _LIBCPP_TEMPLATE_VIS hash<unsigned char>
1346    : public unary_function<unsigned char, size_t>
1347{
1348    _LIBCPP_INLINE_VISIBILITY
1349    size_t operator()(unsigned char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1350};
1351
1352#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
1353
1354template <>
1355struct _LIBCPP_TEMPLATE_VIS hash<char16_t>
1356    : public unary_function<char16_t, size_t>
1357{
1358    _LIBCPP_INLINE_VISIBILITY
1359    size_t operator()(char16_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1360};
1361
1362template <>
1363struct _LIBCPP_TEMPLATE_VIS hash<char32_t>
1364    : public unary_function<char32_t, size_t>
1365{
1366    _LIBCPP_INLINE_VISIBILITY
1367    size_t operator()(char32_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1368};
1369
1370#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
1371
1372template <>
1373struct _LIBCPP_TEMPLATE_VIS hash<wchar_t>
1374    : public unary_function<wchar_t, size_t>
1375{
1376    _LIBCPP_INLINE_VISIBILITY
1377    size_t operator()(wchar_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1378};
1379
1380template <>
1381struct _LIBCPP_TEMPLATE_VIS hash<short>
1382    : public unary_function<short, size_t>
1383{
1384    _LIBCPP_INLINE_VISIBILITY
1385    size_t operator()(short __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1386};
1387
1388template <>
1389struct _LIBCPP_TEMPLATE_VIS hash<unsigned short>
1390    : public unary_function<unsigned short, size_t>
1391{
1392    _LIBCPP_INLINE_VISIBILITY
1393    size_t operator()(unsigned short __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1394};
1395
1396template <>
1397struct _LIBCPP_TEMPLATE_VIS hash<int>
1398    : public unary_function<int, size_t>
1399{
1400    _LIBCPP_INLINE_VISIBILITY
1401    size_t operator()(int __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1402};
1403
1404template <>
1405struct _LIBCPP_TEMPLATE_VIS hash<unsigned int>
1406    : public unary_function<unsigned int, size_t>
1407{
1408    _LIBCPP_INLINE_VISIBILITY
1409    size_t operator()(unsigned int __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1410};
1411
1412template <>
1413struct _LIBCPP_TEMPLATE_VIS hash<long>
1414    : public unary_function<long, size_t>
1415{
1416    _LIBCPP_INLINE_VISIBILITY
1417    size_t operator()(long __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1418};
1419
1420template <>
1421struct _LIBCPP_TEMPLATE_VIS hash<unsigned long>
1422    : public unary_function<unsigned long, size_t>
1423{
1424    _LIBCPP_INLINE_VISIBILITY
1425    size_t operator()(unsigned long __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1426};
1427
1428template <>
1429struct _LIBCPP_TEMPLATE_VIS hash<long long>
1430    : public __scalar_hash<long long>
1431{
1432};
1433
1434template <>
1435struct _LIBCPP_TEMPLATE_VIS hash<unsigned long long>
1436    : public __scalar_hash<unsigned long long>
1437{
1438};
1439
1440#ifndef _LIBCPP_HAS_NO_INT128
1441
1442template <>
1443struct _LIBCPP_TEMPLATE_VIS hash<__int128_t>
1444    : public __scalar_hash<__int128_t>
1445{
1446};
1447
1448template <>
1449struct _LIBCPP_TEMPLATE_VIS hash<__uint128_t>
1450    : public __scalar_hash<__uint128_t>
1451{
1452};
1453
1454#endif
1455
1456template <>
1457struct _LIBCPP_TEMPLATE_VIS hash<float>
1458    : public __scalar_hash<float>
1459{
1460    _LIBCPP_INLINE_VISIBILITY
1461    size_t operator()(float __v) const _NOEXCEPT
1462    {
1463        // -0.0 and 0.0 should return same hash
1464       if (__v == 0.0)
1465           return 0;
1466        return __scalar_hash<float>::operator()(__v);
1467    }
1468};
1469
1470template <>
1471struct _LIBCPP_TEMPLATE_VIS hash<double>
1472    : public __scalar_hash<double>
1473{
1474    _LIBCPP_INLINE_VISIBILITY
1475    size_t operator()(double __v) const _NOEXCEPT
1476    {
1477        // -0.0 and 0.0 should return same hash
1478       if (__v == 0.0)
1479           return 0;
1480        return __scalar_hash<double>::operator()(__v);
1481    }
1482};
1483
1484template <>
1485struct _LIBCPP_TEMPLATE_VIS hash<long double>
1486    : public __scalar_hash<long double>
1487{
1488    _LIBCPP_INLINE_VISIBILITY
1489    size_t operator()(long double __v) const _NOEXCEPT
1490    {
1491        // -0.0 and 0.0 should return same hash
1492        if (__v == 0.0)
1493            return 0;
1494#if defined(__i386__)
1495        // Zero out padding bits
1496        union
1497        {
1498            long double __t;
1499            struct
1500            {
1501                size_t __a;
1502                size_t __b;
1503                size_t __c;
1504                size_t __d;
1505            } __s;
1506        } __u;
1507        __u.__s.__a = 0;
1508        __u.__s.__b = 0;
1509        __u.__s.__c = 0;
1510        __u.__s.__d = 0;
1511        __u.__t = __v;
1512        return __u.__s.__a ^ __u.__s.__b ^ __u.__s.__c ^ __u.__s.__d;
1513#elif defined(__x86_64__)
1514        // Zero out padding bits
1515        union
1516        {
1517            long double __t;
1518            struct
1519            {
1520                size_t __a;
1521                size_t __b;
1522            } __s;
1523        } __u;
1524        __u.__s.__a = 0;
1525        __u.__s.__b = 0;
1526        __u.__t = __v;
1527        return __u.__s.__a ^ __u.__s.__b;
1528#else
1529        return __scalar_hash<long double>::operator()(__v);
1530#endif
1531    }
1532};
1533
1534#if _LIBCPP_STD_VER > 11
1535
1536template <class _Tp, bool = is_enum<_Tp>::value>
1537struct _LIBCPP_TEMPLATE_VIS __enum_hash
1538    : public unary_function<_Tp, size_t>
1539{
1540    _LIBCPP_INLINE_VISIBILITY
1541    size_t operator()(_Tp __v) const _NOEXCEPT
1542    {
1543        typedef typename underlying_type<_Tp>::type type;
1544        return hash<type>{}(static_cast<type>(__v));
1545    }
1546};
1547template <class _Tp>
1548struct _LIBCPP_TEMPLATE_VIS __enum_hash<_Tp, false> {
1549    __enum_hash() = delete;
1550    __enum_hash(__enum_hash const&) = delete;
1551    __enum_hash& operator=(__enum_hash const&) = delete;
1552};
1553
1554template <class _Tp>
1555struct _LIBCPP_TEMPLATE_VIS hash : public __enum_hash<_Tp>
1556{
1557};
1558#endif
1559
1560#if _LIBCPP_STD_VER > 14
1561
1562template <>
1563struct _LIBCPP_TEMPLATE_VIS hash<nullptr_t>
1564  : public unary_function<nullptr_t, size_t>
1565{
1566  _LIBCPP_INLINE_VISIBILITY
1567  size_t operator()(nullptr_t) const _NOEXCEPT {
1568    return 662607004ull;
1569  }
1570};
1571#endif
1572
1573#ifndef _LIBCPP_CXX03_LANG
1574template <class _Key, class _Hash>
1575using __check_hash_requirements = integral_constant<bool,
1576    is_copy_constructible<_Hash>::value &&
1577    is_move_constructible<_Hash>::value &&
1578    __invokable_r<size_t, _Hash, _Key const&>::value
1579>;
1580
1581template <class _Key, class _Hash = std::hash<_Key> >
1582using __has_enabled_hash = integral_constant<bool,
1583    __check_hash_requirements<_Key, _Hash>::value &&
1584    is_default_constructible<_Hash>::value
1585>;
1586
1587#if _LIBCPP_STD_VER > 14
1588template <class _Type, class>
1589using __enable_hash_helper_imp = _Type;
1590
1591template <class _Type, class ..._Keys>
1592using __enable_hash_helper = __enable_hash_helper_imp<_Type,
1593  typename enable_if<__all<__has_enabled_hash<_Keys>::value...>::value>::type
1594>;
1595#else
1596template <class _Type, class ...>
1597using __enable_hash_helper = _Type;
1598#endif
1599
1600#endif // !_LIBCPP_CXX03_LANG
1601
1602_LIBCPP_END_NAMESPACE_STD
1603
1604#endif  // _LIBCPP_UTILITY
1605