xref: /freebsd-12.1/contrib/libc++/include/utility (revision 540d2a8b)
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> constexpr add_const<T>_t& as_const(T& t) noexcept;      // C++17
56template <class T>                      void as_const(const T&&) = delete; // C++17
57
58template <class T> typename add_rvalue_reference<T>::type declval() noexcept;
59
60template <class T1, class T2>
61struct pair
62{
63    typedef T1 first_type;
64    typedef T2 second_type;
65
66    T1 first;
67    T2 second;
68
69    pair(const pair&) = default;
70    pair(pair&&) = default;
71    constexpr pair();
72    pair(const T1& x, const T2& y);                          // constexpr in C++14
73    template <class U, class V> pair(U&& x, V&& y);          // constexpr in C++14
74    template <class U, class V> pair(const pair<U, V>& p);   // constexpr in C++14
75    template <class U, class V> pair(pair<U, V>&& p);        // constexpr in C++14
76    template <class... Args1, class... Args2>
77        pair(piecewise_construct_t, tuple<Args1...> first_args,
78             tuple<Args2...> second_args);
79
80    template <class U, class V> pair& operator=(const pair<U, V>& p);
81    pair& operator=(pair&& p) noexcept(is_nothrow_move_assignable<T1>::value &&
82                                       is_nothrow_move_assignable<T2>::value);
83    template <class U, class V> pair& operator=(pair<U, V>&& p);
84
85    void swap(pair& p) noexcept(is_nothrow_swappable_v<T1> &&
86                                is_nothrow_swappable_v<T2>);
87};
88
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
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
95
96template <class T1, class T2> pair<V1, V2> make_pair(T1&&, T2&&);   // constexpr in C++14
97template <class T1, class T2>
98void
99swap(pair<T1, T2>& x, pair<T1, T2>& y) noexcept(noexcept(x.swap(y)));
100
101struct piecewise_construct_t { };
102constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
103
104template <class T> class tuple_size;
105template <size_t I, class T> class tuple_element;
106
107template <class T1, class T2> struct tuple_size<pair<T1, T2> >;
108template <class T1, class T2> struct tuple_element<0, pair<T1, T2> >;
109template <class T1, class T2> struct tuple_element<1, pair<T1, T2> >;
110
111template<size_t I, class T1, class T2>
112    typename tuple_element<I, pair<T1, T2> >::type&
113    get(pair<T1, T2>&) noexcept; // constexpr in C++14
114
115template<size_t I, class T1, class T2>
116    const typename tuple_element<I, pair<T1, T2> >::type&
117    get(const pair<T1, T2>&) noexcept; // constexpr in C++14
118
119template<size_t I, class T1, class T2>
120    typename tuple_element<I, pair<T1, T2> >::type&&
121    get(pair<T1, T2>&&) noexcept; // constexpr in C++14
122
123template<size_t I, class T1, class T2>
124    const typename tuple_element<I, pair<T1, T2> >::type&&
125    get(const pair<T1, T2>&&) noexcept; // constexpr in C++14
126
127template<class T1, class T2>
128    constexpr T1& get(pair<T1, T2>&) noexcept; // C++14
129
130template<class T1, class T2>
131    constexpr const T1& get(const pair<T1, T2>&) noexcept; // C++14
132
133template<class T1, class T2>
134    constexpr T1&& get(pair<T1, T2>&&) noexcept; // C++14
135
136template<class T1, class T2>
137    constexpr const T1&& get(const pair<T1, T2>&&) noexcept; // C++14
138
139template<class T1, class T2>
140    constexpr T1& get(pair<T2, T1>&) noexcept; // C++14
141
142template<class T1, class T2>
143    constexpr const T1& get(const pair<T2, T1>&) noexcept; // C++14
144
145template<class T1, class T2>
146    constexpr T1&& get(pair<T2, T1>&&) noexcept; // C++14
147
148template<class T1, class T2>
149    constexpr const T1&& get(const pair<T2, T1>&&) noexcept; // C++14
150
151// C++14
152
153template<class T, T... I>
154struct integer_sequence
155{
156    typedef T value_type;
157
158    static constexpr size_t size() noexcept;
159};
160
161template<size_t... I>
162  using index_sequence = integer_sequence<size_t, I...>;
163
164template<class T, T N>
165  using make_integer_sequence = integer_sequence<T, 0, 1, ..., N-1>;
166template<size_t N>
167  using make_index_sequence = make_integer_sequence<size_t, N>;
168
169template<class... T>
170  using index_sequence_for = make_index_sequence<sizeof...(T)>;
171
172template<class T, class U=T>
173    T exchange(T& obj, U&& new_value);
174
175// 20.2.7, in-place construction // C++17
176struct in_place_t {
177  explicit in_place_t() = default;
178};
179inline constexpr in_place_t in_place{};
180template <class T>
181  struct in_place_type_t {
182    explicit in_place_type_t() = default;
183  };
184template <class T>
185  inline constexpr in_place_type_t<T> in_place_type{};
186template <size_t I>
187  struct in_place_index_t {
188    explicit in_place_index_t() = default;
189  };
190template <size_t I>
191  inline constexpr in_place_index_t<I> in_place_index{};
192
193}  // std
194
195*/
196
197#include <__config>
198#include <__tuple>
199#include <type_traits>
200#include <initializer_list>
201#include <cstddef>
202#include <cstring>
203#include <cstdint>
204#include <__debug>
205
206#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
207#pragma GCC system_header
208#endif
209
210_LIBCPP_BEGIN_NAMESPACE_STD
211
212namespace rel_ops
213{
214
215template<class _Tp>
216inline _LIBCPP_INLINE_VISIBILITY
217bool
218operator!=(const _Tp& __x, const _Tp& __y)
219{
220    return !(__x == __y);
221}
222
223template<class _Tp>
224inline _LIBCPP_INLINE_VISIBILITY
225bool
226operator> (const _Tp& __x, const _Tp& __y)
227{
228    return __y < __x;
229}
230
231template<class _Tp>
232inline _LIBCPP_INLINE_VISIBILITY
233bool
234operator<=(const _Tp& __x, const _Tp& __y)
235{
236    return !(__y < __x);
237}
238
239template<class _Tp>
240inline _LIBCPP_INLINE_VISIBILITY
241bool
242operator>=(const _Tp& __x, const _Tp& __y)
243{
244    return !(__x < __y);
245}
246
247}  // rel_ops
248
249// swap_ranges
250
251
252template <class _ForwardIterator1, class _ForwardIterator2>
253inline _LIBCPP_INLINE_VISIBILITY
254_ForwardIterator2
255swap_ranges(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2)
256{
257    for(; __first1 != __last1; ++__first1, (void) ++__first2)
258        swap(*__first1, *__first2);
259    return __first2;
260}
261
262// forward declared in <type_traits>
263template<class _Tp, size_t _Np>
264inline _LIBCPP_INLINE_VISIBILITY
265typename enable_if<
266    __is_swappable<_Tp>::value
267>::type
268swap(_Tp (&__a)[_Np], _Tp (&__b)[_Np]) _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value)
269{
270    _VSTD::swap_ranges(__a, __a + _Np, __b);
271}
272
273template <class _Tp>
274inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
275#ifndef _LIBCPP_CXX03_LANG
276typename conditional
277<
278    !is_nothrow_move_constructible<_Tp>::value && is_copy_constructible<_Tp>::value,
279    const _Tp&,
280    _Tp&&
281>::type
282#else  // _LIBCPP_CXX03_LANG
283const _Tp&
284#endif
285move_if_noexcept(_Tp& __x) _NOEXCEPT
286{
287    return _VSTD::move(__x);
288}
289
290#if _LIBCPP_STD_VER > 14
291template <class _Tp> constexpr add_const_t<_Tp>& as_const(_Tp& __t) noexcept { return __t; }
292template <class _Tp>                        void as_const(const _Tp&&) = delete;
293#endif
294
295struct _LIBCPP_TEMPLATE_VIS piecewise_construct_t { };
296#if defined(_LIBCPP_CXX03_LANG) || defined(_LIBCPP_BUILDING_UTILITY)
297extern const piecewise_construct_t piecewise_construct;// = piecewise_construct_t();
298#else
299constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
300#endif
301
302#if defined(_LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR)
303struct __non_trivially_copyable_base {
304  _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
305  __non_trivially_copyable_base() _NOEXCEPT {}
306  _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
307  __non_trivially_copyable_base(__non_trivially_copyable_base const&) _NOEXCEPT {}
308};
309#endif
310
311template <class _T1, class _T2>
312struct _LIBCPP_TEMPLATE_VIS pair
313#if defined(_LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR)
314: private __non_trivially_copyable_base
315#endif
316{
317    typedef _T1 first_type;
318    typedef _T2 second_type;
319
320    _T1 first;
321    _T2 second;
322
323#if !defined(_LIBCPP_CXX03_LANG)
324    pair(pair const&) = default;
325    pair(pair&&) = default;
326#else
327  // Use the implicitly declared copy constructor in C++03
328#endif
329
330#ifdef _LIBCPP_CXX03_LANG
331    _LIBCPP_INLINE_VISIBILITY
332    pair() : first(), second() {}
333
334    _LIBCPP_INLINE_VISIBILITY
335    pair(_T1 const& __t1, _T2 const& __t2) : first(__t1), second(__t2) {}
336
337    template <class _U1, class _U2>
338    _LIBCPP_INLINE_VISIBILITY
339    pair(const pair<_U1, _U2>& __p) : first(__p.first), second(__p.second) {}
340
341    _LIBCPP_INLINE_VISIBILITY
342    pair& operator=(pair const& __p) {
343        first = __p.first;
344        second = __p.second;
345        return *this;
346    }
347#else
348    template <bool _Val>
349    using _EnableB = typename enable_if<_Val, bool>::type;
350
351    struct _CheckArgs {
352      template <class _U1, class _U2>
353      static constexpr bool __enable_default() {
354          return is_default_constructible<_U1>::value
355              && is_default_constructible<_U2>::value;
356      }
357
358      template <class _U1, class _U2>
359      static constexpr bool __enable_explicit() {
360          return is_constructible<first_type, _U1>::value
361              && is_constructible<second_type, _U2>::value
362              && (!is_convertible<_U1, first_type>::value
363                  || !is_convertible<_U2, second_type>::value);
364      }
365
366      template <class _U1, class _U2>
367      static constexpr bool __enable_implicit() {
368          return is_constructible<first_type, _U1>::value
369              && is_constructible<second_type, _U2>::value
370              && is_convertible<_U1, first_type>::value
371              && is_convertible<_U2, second_type>::value;
372      }
373    };
374
375    template <bool _MaybeEnable>
376    using _CheckArgsDep = typename conditional<
377      _MaybeEnable, _CheckArgs, __check_tuple_constructor_fail>::type;
378
379    struct _CheckTupleLikeConstructor {
380        template <class _Tuple>
381        static constexpr bool __enable_implicit() {
382            return __tuple_convertible<_Tuple, pair>::value;
383        }
384
385        template <class _Tuple>
386        static constexpr bool __enable_explicit() {
387            return __tuple_constructible<_Tuple, pair>::value
388               && !__tuple_convertible<_Tuple, pair>::value;
389        }
390
391        template <class _Tuple>
392        static constexpr bool __enable_assign() {
393            return __tuple_assignable<_Tuple, pair>::value;
394        }
395    };
396
397    template <class _Tuple>
398    using _CheckTLC = typename conditional<
399        __tuple_like_with_size<_Tuple, 2>::value
400            && !is_same<typename decay<_Tuple>::type, pair>::value,
401        _CheckTupleLikeConstructor,
402        __check_tuple_constructor_fail
403    >::type;
404
405    template<bool _Dummy = true, _EnableB<
406            _CheckArgsDep<_Dummy>::template __enable_default<_T1, _T2>()
407    > = false>
408    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
409    pair() : first(), second() {}
410
411    template <bool _Dummy = true, _EnableB<
412             _CheckArgsDep<_Dummy>::template __enable_explicit<_T1 const&, _T2 const&>()
413    > = false>
414    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
415    explicit pair(_T1 const& __t1, _T2 const& __t2)
416        : first(__t1), second(__t2) {}
417
418    template<bool _Dummy = true, _EnableB<
419            _CheckArgsDep<_Dummy>::template __enable_implicit<_T1 const&, _T2 const&>()
420    > = false>
421    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
422    pair(_T1 const& __t1, _T2 const& __t2)
423        : first(__t1), second(__t2) {}
424
425    template<class _U1, class _U2, _EnableB<
426             _CheckArgs::template __enable_explicit<_U1, _U2>()
427    > = false>
428    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
429    explicit pair(_U1&& __u1, _U2&& __u2)
430        : first(_VSTD::forward<_U1>(__u1)), second(_VSTD::forward<_U2>(__u2)) {}
431
432    template<class _U1, class _U2, _EnableB<
433            _CheckArgs::template __enable_implicit<_U1, _U2>()
434    > = false>
435    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
436    pair(_U1&& __u1, _U2&& __u2)
437        : first(_VSTD::forward<_U1>(__u1)), second(_VSTD::forward<_U2>(__u2)) {}
438
439    template<class _U1, class _U2, _EnableB<
440            _CheckArgs::template __enable_explicit<_U1 const&, _U2 const&>()
441    > = false>
442    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
443    explicit pair(pair<_U1, _U2> const& __p)
444        : first(__p.first), second(__p.second) {}
445
446    template<class _U1, class _U2, _EnableB<
447            _CheckArgs::template __enable_implicit<_U1 const&, _U2 const&>()
448    > = false>
449    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
450    pair(pair<_U1, _U2> const& __p)
451        : first(__p.first), second(__p.second) {}
452
453    template<class _U1, class _U2, _EnableB<
454            _CheckArgs::template __enable_explicit<_U1, _U2>()
455    > = false>
456    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
457    explicit pair(pair<_U1, _U2>&&__p)
458        : first(_VSTD::forward<_U1>(__p.first)), second(_VSTD::forward<_U2>(__p.second)) {}
459
460    template<class _U1, class _U2, _EnableB<
461            _CheckArgs::template __enable_implicit<_U1, _U2>()
462    > = false>
463    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
464    pair(pair<_U1, _U2>&& __p)
465        : first(_VSTD::forward<_U1>(__p.first)), second(_VSTD::forward<_U2>(__p.second)) {}
466
467    template<class _Tuple, _EnableB<
468            _CheckTLC<_Tuple>::template __enable_explicit<_Tuple>()
469    > = false>
470    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
471    explicit pair(_Tuple&& __p)
472        : first(_VSTD::get<0>(_VSTD::forward<_Tuple>(__p))),
473          second(_VSTD::get<1>(_VSTD::forward<_Tuple>(__p))) {}
474
475    template<class _Tuple, _EnableB<
476            _CheckTLC<_Tuple>::template __enable_implicit<_Tuple>()
477    > = false>
478    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
479    pair(_Tuple&& __p)
480        : first(_VSTD::get<0>(_VSTD::forward<_Tuple>(__p))),
481          second(_VSTD::get<1>(_VSTD::forward<_Tuple>(__p))) {}
482
483    template <class... _Args1, class... _Args2>
484    _LIBCPP_INLINE_VISIBILITY
485    pair(piecewise_construct_t __pc,
486         tuple<_Args1...> __first_args, tuple<_Args2...> __second_args)
487        : pair(__pc, __first_args, __second_args,
488                typename __make_tuple_indices<sizeof...(_Args1)>::type(),
489                typename __make_tuple_indices<sizeof...(_Args2) >::type()) {}
490
491    _LIBCPP_INLINE_VISIBILITY
492    pair& operator=(typename conditional<
493                        is_copy_assignable<first_type>::value &&
494                        is_copy_assignable<second_type>::value,
495                    pair, __nat>::type const& __p)
496        _NOEXCEPT_(is_nothrow_copy_assignable<first_type>::value &&
497                   is_nothrow_copy_assignable<second_type>::value)
498    {
499        first = __p.first;
500        second = __p.second;
501        return *this;
502    }
503
504    _LIBCPP_INLINE_VISIBILITY
505    pair& operator=(typename conditional<
506                        is_move_assignable<first_type>::value &&
507                        is_move_assignable<second_type>::value,
508                    pair, __nat>::type&& __p)
509        _NOEXCEPT_(is_nothrow_move_assignable<first_type>::value &&
510                   is_nothrow_move_assignable<second_type>::value)
511    {
512        first = _VSTD::forward<first_type>(__p.first);
513        second = _VSTD::forward<second_type>(__p.second);
514        return *this;
515    }
516
517    template <class _Tuple, _EnableB<
518            _CheckTLC<_Tuple>::template __enable_assign<_Tuple>()
519     > = false>
520    _LIBCPP_INLINE_VISIBILITY
521    pair& operator=(_Tuple&& __p) {
522        first = _VSTD::get<0>(_VSTD::forward<_Tuple>(__p));
523        second = _VSTD::get<1>(_VSTD::forward<_Tuple>(__p));
524        return *this;
525    }
526#endif
527
528    _LIBCPP_INLINE_VISIBILITY
529    void
530    swap(pair& __p) _NOEXCEPT_(__is_nothrow_swappable<first_type>::value &&
531                               __is_nothrow_swappable<second_type>::value)
532    {
533        using _VSTD::swap;
534        swap(first,  __p.first);
535        swap(second, __p.second);
536    }
537private:
538
539#ifndef _LIBCPP_CXX03_LANG
540    template <class... _Args1, class... _Args2, size_t... _I1, size_t... _I2>
541        _LIBCPP_INLINE_VISIBILITY
542        pair(piecewise_construct_t,
543             tuple<_Args1...>& __first_args, tuple<_Args2...>& __second_args,
544             __tuple_indices<_I1...>, __tuple_indices<_I2...>);
545#endif
546};
547
548template <class _T1, class _T2>
549inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
550bool
551operator==(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
552{
553    return __x.first == __y.first && __x.second == __y.second;
554}
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 == __y);
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.first < __y.first || (!(__y.first < __x.first) && __x.second < __y.second);
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 __y < __x;
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 !(__x < __y);
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 !(__y < __x);
594}
595
596template <class _T1, class _T2>
597inline _LIBCPP_INLINE_VISIBILITY
598typename enable_if
599<
600    __is_swappable<_T1>::value &&
601    __is_swappable<_T2>::value,
602    void
603>::type
604swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y)
605                     _NOEXCEPT_((__is_nothrow_swappable<_T1>::value &&
606                                 __is_nothrow_swappable<_T2>::value))
607{
608    __x.swap(__y);
609}
610
611#ifndef _LIBCPP_CXX03_LANG
612
613template <class _Tp>
614struct __make_pair_return_impl
615{
616    typedef _Tp type;
617};
618
619template <class _Tp>
620struct __make_pair_return_impl<reference_wrapper<_Tp>>
621{
622    typedef _Tp& type;
623};
624
625template <class _Tp>
626struct __make_pair_return
627{
628    typedef typename __make_pair_return_impl<typename decay<_Tp>::type>::type type;
629};
630
631template <class _T1, class _T2>
632inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
633pair<typename __make_pair_return<_T1>::type, typename __make_pair_return<_T2>::type>
634make_pair(_T1&& __t1, _T2&& __t2)
635{
636    return pair<typename __make_pair_return<_T1>::type, typename __make_pair_return<_T2>::type>
637               (_VSTD::forward<_T1>(__t1), _VSTD::forward<_T2>(__t2));
638}
639
640#else  // _LIBCPP_CXX03_LANG
641
642template <class _T1, class _T2>
643inline _LIBCPP_INLINE_VISIBILITY
644pair<_T1,_T2>
645make_pair(_T1 __x, _T2 __y)
646{
647    return pair<_T1, _T2>(__x, __y);
648}
649
650#endif  // _LIBCPP_CXX03_LANG
651
652template <class _T1, class _T2>
653  class _LIBCPP_TEMPLATE_VIS tuple_size<pair<_T1, _T2> >
654    : public integral_constant<size_t, 2> {};
655
656template <class _T1, class _T2>
657class _LIBCPP_TEMPLATE_VIS tuple_element<0, pair<_T1, _T2> >
658{
659public:
660    typedef _T1 type;
661};
662
663template <class _T1, class _T2>
664class _LIBCPP_TEMPLATE_VIS tuple_element<1, pair<_T1, _T2> >
665{
666public:
667    typedef _T2 type;
668};
669
670template <size_t _Ip> struct __get_pair;
671
672template <>
673struct __get_pair<0>
674{
675    template <class _T1, class _T2>
676    static
677    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
678    _T1&
679    get(pair<_T1, _T2>& __p) _NOEXCEPT {return __p.first;}
680
681    template <class _T1, class _T2>
682    static
683    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
684    const _T1&
685    get(const pair<_T1, _T2>& __p) _NOEXCEPT {return __p.first;}
686
687#ifndef _LIBCPP_CXX03_LANG
688    template <class _T1, class _T2>
689    static
690    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
691    _T1&&
692    get(pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<_T1>(__p.first);}
693
694    template <class _T1, class _T2>
695    static
696    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
697    const _T1&&
698    get(const pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<const _T1>(__p.first);}
699#endif  // _LIBCPP_CXX03_LANG
700};
701
702template <>
703struct __get_pair<1>
704{
705    template <class _T1, class _T2>
706    static
707    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
708    _T2&
709    get(pair<_T1, _T2>& __p) _NOEXCEPT {return __p.second;}
710
711    template <class _T1, class _T2>
712    static
713    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
714    const _T2&
715    get(const pair<_T1, _T2>& __p) _NOEXCEPT {return __p.second;}
716
717#ifndef _LIBCPP_CXX03_LANG
718    template <class _T1, class _T2>
719    static
720    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
721    _T2&&
722    get(pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<_T2>(__p.second);}
723
724    template <class _T1, class _T2>
725    static
726    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
727    const _T2&&
728    get(const pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<const _T2>(__p.second);}
729#endif  // _LIBCPP_CXX03_LANG
730};
731
732template <size_t _Ip, class _T1, class _T2>
733inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
734typename tuple_element<_Ip, pair<_T1, _T2> >::type&
735get(pair<_T1, _T2>& __p) _NOEXCEPT
736{
737    return __get_pair<_Ip>::get(__p);
738}
739
740template <size_t _Ip, class _T1, class _T2>
741inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
742const typename tuple_element<_Ip, pair<_T1, _T2> >::type&
743get(const pair<_T1, _T2>& __p) _NOEXCEPT
744{
745    return __get_pair<_Ip>::get(__p);
746}
747
748#ifndef _LIBCPP_CXX03_LANG
749template <size_t _Ip, class _T1, class _T2>
750inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
751typename tuple_element<_Ip, pair<_T1, _T2> >::type&&
752get(pair<_T1, _T2>&& __p) _NOEXCEPT
753{
754    return __get_pair<_Ip>::get(_VSTD::move(__p));
755}
756
757template <size_t _Ip, class _T1, class _T2>
758inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
759const typename tuple_element<_Ip, pair<_T1, _T2> >::type&&
760get(const pair<_T1, _T2>&& __p) _NOEXCEPT
761{
762    return __get_pair<_Ip>::get(_VSTD::move(__p));
763}
764#endif  // _LIBCPP_CXX03_LANG
765
766#if _LIBCPP_STD_VER > 11
767template <class _T1, class _T2>
768inline _LIBCPP_INLINE_VISIBILITY
769constexpr _T1 & get(pair<_T1, _T2>& __p) _NOEXCEPT
770{
771    return __get_pair<0>::get(__p);
772}
773
774template <class _T1, class _T2>
775inline _LIBCPP_INLINE_VISIBILITY
776constexpr _T1 const & get(pair<_T1, _T2> const& __p) _NOEXCEPT
777{
778    return __get_pair<0>::get(__p);
779}
780
781template <class _T1, class _T2>
782inline _LIBCPP_INLINE_VISIBILITY
783constexpr _T1 && get(pair<_T1, _T2>&& __p) _NOEXCEPT
784{
785    return __get_pair<0>::get(_VSTD::move(__p));
786}
787
788template <class _T1, class _T2>
789inline _LIBCPP_INLINE_VISIBILITY
790constexpr _T1 const && get(pair<_T1, _T2> const&& __p) _NOEXCEPT
791{
792    return __get_pair<0>::get(_VSTD::move(__p));
793}
794
795template <class _T1, class _T2>
796inline _LIBCPP_INLINE_VISIBILITY
797constexpr _T1 & get(pair<_T2, _T1>& __p) _NOEXCEPT
798{
799    return __get_pair<1>::get(__p);
800}
801
802template <class _T1, class _T2>
803inline _LIBCPP_INLINE_VISIBILITY
804constexpr _T1 const & get(pair<_T2, _T1> const& __p) _NOEXCEPT
805{
806    return __get_pair<1>::get(__p);
807}
808
809template <class _T1, class _T2>
810inline _LIBCPP_INLINE_VISIBILITY
811constexpr _T1 && get(pair<_T2, _T1>&& __p) _NOEXCEPT
812{
813    return __get_pair<1>::get(_VSTD::move(__p));
814}
815
816template <class _T1, class _T2>
817inline _LIBCPP_INLINE_VISIBILITY
818constexpr _T1 const && get(pair<_T2, _T1> const&& __p) _NOEXCEPT
819{
820    return __get_pair<1>::get(_VSTD::move(__p));
821}
822
823#endif
824
825#if _LIBCPP_STD_VER > 11
826
827template<class _Tp, _Tp... _Ip>
828struct _LIBCPP_TEMPLATE_VIS integer_sequence
829{
830    typedef _Tp value_type;
831    static_assert( is_integral<_Tp>::value,
832                  "std::integer_sequence can only be instantiated with an integral type" );
833    static
834    _LIBCPP_INLINE_VISIBILITY
835    constexpr
836    size_t
837    size() noexcept { return sizeof...(_Ip); }
838};
839
840template<size_t... _Ip>
841    using index_sequence = integer_sequence<size_t, _Ip...>;
842
843#if __has_builtin(__make_integer_seq) && !defined(_LIBCPP_TESTING_FALLBACK_MAKE_INTEGER_SEQUENCE)
844
845template <class _Tp, _Tp _Ep>
846using __make_integer_sequence = __make_integer_seq<integer_sequence, _Tp, _Ep>;
847
848#else
849
850template<typename _Tp, _Tp _Np> using __make_integer_sequence_unchecked =
851  typename __detail::__make<_Np>::type::template __convert<integer_sequence, _Tp>;
852
853template <class _Tp, _Tp _Ep>
854struct __make_integer_sequence_checked
855{
856    static_assert(is_integral<_Tp>::value,
857                  "std::make_integer_sequence can only be instantiated with an integral type" );
858    static_assert(0 <= _Ep, "std::make_integer_sequence must have a non-negative sequence length");
859    // Workaround GCC bug by preventing bad installations when 0 <= _Ep
860    // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68929
861    typedef __make_integer_sequence_unchecked<_Tp, 0 <= _Ep ? _Ep : 0> type;
862};
863
864template <class _Tp, _Tp _Ep>
865using __make_integer_sequence = typename __make_integer_sequence_checked<_Tp, _Ep>::type;
866
867#endif
868
869template<class _Tp, _Tp _Np>
870    using make_integer_sequence = __make_integer_sequence<_Tp, _Np>;
871
872template<size_t _Np>
873    using make_index_sequence = make_integer_sequence<size_t, _Np>;
874
875template<class... _Tp>
876    using index_sequence_for = make_index_sequence<sizeof...(_Tp)>;
877
878#endif  // _LIBCPP_STD_VER > 11
879
880#if _LIBCPP_STD_VER > 11
881template<class _T1, class _T2 = _T1>
882inline _LIBCPP_INLINE_VISIBILITY
883_T1 exchange(_T1& __obj, _T2 && __new_value)
884{
885    _T1 __old_value = _VSTD::move(__obj);
886    __obj = _VSTD::forward<_T2>(__new_value);
887    return __old_value;
888}
889#endif  // _LIBCPP_STD_VER > 11
890
891#if _LIBCPP_STD_VER > 14
892
893struct _LIBCPP_TYPE_VIS in_place_t {
894    explicit in_place_t() = default;
895};
896#ifndef _LIBCPP_HAS_NO_INLINE_VARIABLES
897inline
898#endif
899constexpr in_place_t in_place{};
900
901template <class _Tp>
902struct _LIBCPP_TEMPLATE_VIS in_place_type_t {
903    explicit in_place_type_t() = default;
904};
905template <class _Tp>
906#ifndef _LIBCPP_HAS_NO_INLINE_VARIABLES
907inline
908#endif
909constexpr in_place_type_t<_Tp> in_place_type{};
910
911template <size_t _Idx>
912struct _LIBCPP_TYPE_VIS in_place_index_t {
913    explicit in_place_index_t() = default;
914};
915template <size_t _Idx>
916#ifndef _LIBCPP_HAS_NO_INLINE_VARIABLES
917inline
918#endif
919constexpr in_place_index_t<_Idx> in_place_index{};
920
921template <class _Tp> struct __is_inplace_type_imp : false_type {};
922template <class _Tp> struct __is_inplace_type_imp<in_place_type_t<_Tp>> : true_type {};
923
924template <class _Tp>
925using __is_inplace_type = __is_inplace_type_imp<__uncvref_t<_Tp>>;
926
927#endif // _LIBCPP_STD_VER > 14
928
929template <class _Arg, class _Result>
930struct _LIBCPP_TEMPLATE_VIS unary_function
931{
932    typedef _Arg    argument_type;
933    typedef _Result result_type;
934};
935
936template <class _Size>
937inline _LIBCPP_INLINE_VISIBILITY
938_Size
939__loadword(const void* __p)
940{
941    _Size __r;
942    std::memcpy(&__r, __p, sizeof(__r));
943    return __r;
944}
945
946// We use murmur2 when size_t is 32 bits, and cityhash64 when size_t
947// is 64 bits.  This is because cityhash64 uses 64bit x 64bit
948// multiplication, which can be very slow on 32-bit systems.
949template <class _Size, size_t = sizeof(_Size)*__CHAR_BIT__>
950struct __murmur2_or_cityhash;
951
952template <class _Size>
953struct __murmur2_or_cityhash<_Size, 32>
954{
955    inline _Size operator()(const void* __key, _Size __len)
956         _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK;
957};
958
959// murmur2
960template <class _Size>
961_Size
962__murmur2_or_cityhash<_Size, 32>::operator()(const void* __key, _Size __len)
963{
964    const _Size __m = 0x5bd1e995;
965    const _Size __r = 24;
966    _Size __h = __len;
967    const unsigned char* __data = static_cast<const unsigned char*>(__key);
968    for (; __len >= 4; __data += 4, __len -= 4)
969    {
970        _Size __k = __loadword<_Size>(__data);
971        __k *= __m;
972        __k ^= __k >> __r;
973        __k *= __m;
974        __h *= __m;
975        __h ^= __k;
976    }
977    switch (__len)
978    {
979    case 3:
980        __h ^= __data[2] << 16;
981    case 2:
982        __h ^= __data[1] << 8;
983    case 1:
984        __h ^= __data[0];
985        __h *= __m;
986    }
987    __h ^= __h >> 13;
988    __h *= __m;
989    __h ^= __h >> 15;
990    return __h;
991}
992
993template <class _Size>
994struct __murmur2_or_cityhash<_Size, 64>
995{
996    inline _Size operator()(const void* __key, _Size __len)  _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK;
997
998 private:
999  // Some primes between 2^63 and 2^64.
1000  static const _Size __k0 = 0xc3a5c85c97cb3127ULL;
1001  static const _Size __k1 = 0xb492b66fbe98f273ULL;
1002  static const _Size __k2 = 0x9ae16a3b2f90404fULL;
1003  static const _Size __k3 = 0xc949d7c7509e6557ULL;
1004
1005  static _Size __rotate(_Size __val, int __shift) {
1006    return __shift == 0 ? __val : ((__val >> __shift) | (__val << (64 - __shift)));
1007  }
1008
1009  static _Size __rotate_by_at_least_1(_Size __val, int __shift) {
1010    return (__val >> __shift) | (__val << (64 - __shift));
1011  }
1012
1013  static _Size __shift_mix(_Size __val) {
1014    return __val ^ (__val >> 47);
1015  }
1016
1017  static _Size __hash_len_16(_Size __u, _Size __v)
1018     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1019  {
1020    const _Size __mul = 0x9ddfea08eb382d69ULL;
1021    _Size __a = (__u ^ __v) * __mul;
1022    __a ^= (__a >> 47);
1023    _Size __b = (__v ^ __a) * __mul;
1024    __b ^= (__b >> 47);
1025    __b *= __mul;
1026    return __b;
1027  }
1028
1029  static _Size __hash_len_0_to_16(const char* __s, _Size __len)
1030     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1031  {
1032    if (__len > 8) {
1033      const _Size __a = __loadword<_Size>(__s);
1034      const _Size __b = __loadword<_Size>(__s + __len - 8);
1035      return __hash_len_16(__a, __rotate_by_at_least_1(__b + __len, __len)) ^ __b;
1036    }
1037    if (__len >= 4) {
1038      const uint32_t __a = __loadword<uint32_t>(__s);
1039      const uint32_t __b = __loadword<uint32_t>(__s + __len - 4);
1040      return __hash_len_16(__len + (__a << 3), __b);
1041    }
1042    if (__len > 0) {
1043      const unsigned char __a = __s[0];
1044      const unsigned char __b = __s[__len >> 1];
1045      const unsigned char __c = __s[__len - 1];
1046      const uint32_t __y = static_cast<uint32_t>(__a) +
1047                           (static_cast<uint32_t>(__b) << 8);
1048      const uint32_t __z = __len + (static_cast<uint32_t>(__c) << 2);
1049      return __shift_mix(__y * __k2 ^ __z * __k3) * __k2;
1050    }
1051    return __k2;
1052  }
1053
1054  static _Size __hash_len_17_to_32(const char *__s, _Size __len)
1055     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1056  {
1057    const _Size __a = __loadword<_Size>(__s) * __k1;
1058    const _Size __b = __loadword<_Size>(__s + 8);
1059    const _Size __c = __loadword<_Size>(__s + __len - 8) * __k2;
1060    const _Size __d = __loadword<_Size>(__s + __len - 16) * __k0;
1061    return __hash_len_16(__rotate(__a - __b, 43) + __rotate(__c, 30) + __d,
1062                         __a + __rotate(__b ^ __k3, 20) - __c + __len);
1063  }
1064
1065  // Return a 16-byte hash for 48 bytes.  Quick and dirty.
1066  // Callers do best to use "random-looking" values for a and b.
1067  static pair<_Size, _Size> __weak_hash_len_32_with_seeds(
1068      _Size __w, _Size __x, _Size __y, _Size __z, _Size __a, _Size __b)
1069        _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1070  {
1071    __a += __w;
1072    __b = __rotate(__b + __a + __z, 21);
1073    const _Size __c = __a;
1074    __a += __x;
1075    __a += __y;
1076    __b += __rotate(__a, 44);
1077    return pair<_Size, _Size>(__a + __z, __b + __c);
1078  }
1079
1080  // Return a 16-byte hash for s[0] ... s[31], a, and b.  Quick and dirty.
1081  static pair<_Size, _Size> __weak_hash_len_32_with_seeds(
1082      const char* __s, _Size __a, _Size __b)
1083    _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1084  {
1085    return __weak_hash_len_32_with_seeds(__loadword<_Size>(__s),
1086                                         __loadword<_Size>(__s + 8),
1087                                         __loadword<_Size>(__s + 16),
1088                                         __loadword<_Size>(__s + 24),
1089                                         __a,
1090                                         __b);
1091  }
1092
1093  // Return an 8-byte hash for 33 to 64 bytes.
1094  static _Size __hash_len_33_to_64(const char *__s, size_t __len)
1095    _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1096  {
1097    _Size __z = __loadword<_Size>(__s + 24);
1098    _Size __a = __loadword<_Size>(__s) +
1099                (__len + __loadword<_Size>(__s + __len - 16)) * __k0;
1100    _Size __b = __rotate(__a + __z, 52);
1101    _Size __c = __rotate(__a, 37);
1102    __a += __loadword<_Size>(__s + 8);
1103    __c += __rotate(__a, 7);
1104    __a += __loadword<_Size>(__s + 16);
1105    _Size __vf = __a + __z;
1106    _Size __vs = __b + __rotate(__a, 31) + __c;
1107    __a = __loadword<_Size>(__s + 16) + __loadword<_Size>(__s + __len - 32);
1108    __z += __loadword<_Size>(__s + __len - 8);
1109    __b = __rotate(__a + __z, 52);
1110    __c = __rotate(__a, 37);
1111    __a += __loadword<_Size>(__s + __len - 24);
1112    __c += __rotate(__a, 7);
1113    __a += __loadword<_Size>(__s + __len - 16);
1114    _Size __wf = __a + __z;
1115    _Size __ws = __b + __rotate(__a, 31) + __c;
1116    _Size __r = __shift_mix((__vf + __ws) * __k2 + (__wf + __vs) * __k0);
1117    return __shift_mix(__r * __k0 + __vs) * __k2;
1118  }
1119};
1120
1121// cityhash64
1122template <class _Size>
1123_Size
1124__murmur2_or_cityhash<_Size, 64>::operator()(const void* __key, _Size __len)
1125{
1126  const char* __s = static_cast<const char*>(__key);
1127  if (__len <= 32) {
1128    if (__len <= 16) {
1129      return __hash_len_0_to_16(__s, __len);
1130    } else {
1131      return __hash_len_17_to_32(__s, __len);
1132    }
1133  } else if (__len <= 64) {
1134    return __hash_len_33_to_64(__s, __len);
1135  }
1136
1137  // For strings over 64 bytes we hash the end first, and then as we
1138  // loop we keep 56 bytes of state: v, w, x, y, and z.
1139  _Size __x = __loadword<_Size>(__s + __len - 40);
1140  _Size __y = __loadword<_Size>(__s + __len - 16) +
1141              __loadword<_Size>(__s + __len - 56);
1142  _Size __z = __hash_len_16(__loadword<_Size>(__s + __len - 48) + __len,
1143                          __loadword<_Size>(__s + __len - 24));
1144  pair<_Size, _Size> __v = __weak_hash_len_32_with_seeds(__s + __len - 64, __len, __z);
1145  pair<_Size, _Size> __w = __weak_hash_len_32_with_seeds(__s + __len - 32, __y + __k1, __x);
1146  __x = __x * __k1 + __loadword<_Size>(__s);
1147
1148  // Decrease len to the nearest multiple of 64, and operate on 64-byte chunks.
1149  __len = (__len - 1) & ~static_cast<_Size>(63);
1150  do {
1151    __x = __rotate(__x + __y + __v.first + __loadword<_Size>(__s + 8), 37) * __k1;
1152    __y = __rotate(__y + __v.second + __loadword<_Size>(__s + 48), 42) * __k1;
1153    __x ^= __w.second;
1154    __y += __v.first + __loadword<_Size>(__s + 40);
1155    __z = __rotate(__z + __w.first, 33) * __k1;
1156    __v = __weak_hash_len_32_with_seeds(__s, __v.second * __k1, __x + __w.first);
1157    __w = __weak_hash_len_32_with_seeds(__s + 32, __z + __w.second,
1158                                        __y + __loadword<_Size>(__s + 16));
1159    std::swap(__z, __x);
1160    __s += 64;
1161    __len -= 64;
1162  } while (__len != 0);
1163  return __hash_len_16(
1164      __hash_len_16(__v.first, __w.first) + __shift_mix(__y) * __k1 + __z,
1165      __hash_len_16(__v.second, __w.second) + __x);
1166}
1167
1168template <class _Tp, size_t = sizeof(_Tp) / sizeof(size_t)>
1169struct __scalar_hash;
1170
1171template <class _Tp>
1172struct __scalar_hash<_Tp, 0>
1173    : public unary_function<_Tp, size_t>
1174{
1175    _LIBCPP_INLINE_VISIBILITY
1176    size_t operator()(_Tp __v) const _NOEXCEPT
1177    {
1178        union
1179        {
1180            _Tp    __t;
1181            size_t __a;
1182        } __u;
1183        __u.__a = 0;
1184        __u.__t = __v;
1185        return __u.__a;
1186    }
1187};
1188
1189template <class _Tp>
1190struct __scalar_hash<_Tp, 1>
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.__t = __v;
1202        return __u.__a;
1203    }
1204};
1205
1206template <class _Tp>
1207struct __scalar_hash<_Tp, 2>
1208    : public unary_function<_Tp, size_t>
1209{
1210    _LIBCPP_INLINE_VISIBILITY
1211    size_t operator()(_Tp __v) const _NOEXCEPT
1212    {
1213        union
1214        {
1215            _Tp __t;
1216            struct
1217            {
1218                size_t __a;
1219                size_t __b;
1220            } __s;
1221        } __u;
1222        __u.__t = __v;
1223        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
1224    }
1225};
1226
1227template <class _Tp>
1228struct __scalar_hash<_Tp, 3>
1229    : public unary_function<_Tp, size_t>
1230{
1231    _LIBCPP_INLINE_VISIBILITY
1232    size_t operator()(_Tp __v) const _NOEXCEPT
1233    {
1234        union
1235        {
1236            _Tp __t;
1237            struct
1238            {
1239                size_t __a;
1240                size_t __b;
1241                size_t __c;
1242            } __s;
1243        } __u;
1244        __u.__t = __v;
1245        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
1246    }
1247};
1248
1249template <class _Tp>
1250struct __scalar_hash<_Tp, 4>
1251    : public unary_function<_Tp, size_t>
1252{
1253    _LIBCPP_INLINE_VISIBILITY
1254    size_t operator()(_Tp __v) const _NOEXCEPT
1255    {
1256        union
1257        {
1258            _Tp __t;
1259            struct
1260            {
1261                size_t __a;
1262                size_t __b;
1263                size_t __c;
1264                size_t __d;
1265            } __s;
1266        } __u;
1267        __u.__t = __v;
1268        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
1269    }
1270};
1271
1272struct _PairT {
1273  size_t first;
1274  size_t second;
1275};
1276
1277_LIBCPP_INLINE_VISIBILITY
1278inline size_t __hash_combine(size_t __lhs, size_t __rhs) _NOEXCEPT {
1279    typedef __scalar_hash<_PairT> _HashT;
1280    const _PairT __p = {__lhs, __rhs};
1281    return _HashT()(__p);
1282}
1283
1284template<class _Tp>
1285struct _LIBCPP_TEMPLATE_VIS hash<_Tp*>
1286    : public unary_function<_Tp*, size_t>
1287{
1288    _LIBCPP_INLINE_VISIBILITY
1289    size_t operator()(_Tp* __v) const _NOEXCEPT
1290    {
1291        union
1292        {
1293            _Tp* __t;
1294            size_t __a;
1295        } __u;
1296        __u.__t = __v;
1297        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
1298    }
1299};
1300
1301
1302template <>
1303struct _LIBCPP_TEMPLATE_VIS hash<bool>
1304    : public unary_function<bool, size_t>
1305{
1306    _LIBCPP_INLINE_VISIBILITY
1307    size_t operator()(bool __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1308};
1309
1310template <>
1311struct _LIBCPP_TEMPLATE_VIS hash<char>
1312    : public unary_function<char, size_t>
1313{
1314    _LIBCPP_INLINE_VISIBILITY
1315    size_t operator()(char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1316};
1317
1318template <>
1319struct _LIBCPP_TEMPLATE_VIS hash<signed char>
1320    : public unary_function<signed char, size_t>
1321{
1322    _LIBCPP_INLINE_VISIBILITY
1323    size_t operator()(signed char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1324};
1325
1326template <>
1327struct _LIBCPP_TEMPLATE_VIS hash<unsigned char>
1328    : public unary_function<unsigned char, size_t>
1329{
1330    _LIBCPP_INLINE_VISIBILITY
1331    size_t operator()(unsigned char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1332};
1333
1334#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
1335
1336template <>
1337struct _LIBCPP_TEMPLATE_VIS hash<char16_t>
1338    : public unary_function<char16_t, size_t>
1339{
1340    _LIBCPP_INLINE_VISIBILITY
1341    size_t operator()(char16_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1342};
1343
1344template <>
1345struct _LIBCPP_TEMPLATE_VIS hash<char32_t>
1346    : public unary_function<char32_t, size_t>
1347{
1348    _LIBCPP_INLINE_VISIBILITY
1349    size_t operator()(char32_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1350};
1351
1352#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
1353
1354template <>
1355struct _LIBCPP_TEMPLATE_VIS hash<wchar_t>
1356    : public unary_function<wchar_t, size_t>
1357{
1358    _LIBCPP_INLINE_VISIBILITY
1359    size_t operator()(wchar_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1360};
1361
1362template <>
1363struct _LIBCPP_TEMPLATE_VIS hash<short>
1364    : public unary_function<short, size_t>
1365{
1366    _LIBCPP_INLINE_VISIBILITY
1367    size_t operator()(short __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1368};
1369
1370template <>
1371struct _LIBCPP_TEMPLATE_VIS hash<unsigned short>
1372    : public unary_function<unsigned short, size_t>
1373{
1374    _LIBCPP_INLINE_VISIBILITY
1375    size_t operator()(unsigned short __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1376};
1377
1378template <>
1379struct _LIBCPP_TEMPLATE_VIS hash<int>
1380    : public unary_function<int, size_t>
1381{
1382    _LIBCPP_INLINE_VISIBILITY
1383    size_t operator()(int __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1384};
1385
1386template <>
1387struct _LIBCPP_TEMPLATE_VIS hash<unsigned int>
1388    : public unary_function<unsigned int, size_t>
1389{
1390    _LIBCPP_INLINE_VISIBILITY
1391    size_t operator()(unsigned int __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1392};
1393
1394template <>
1395struct _LIBCPP_TEMPLATE_VIS hash<long>
1396    : public unary_function<long, size_t>
1397{
1398    _LIBCPP_INLINE_VISIBILITY
1399    size_t operator()(long __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1400};
1401
1402template <>
1403struct _LIBCPP_TEMPLATE_VIS hash<unsigned long>
1404    : public unary_function<unsigned long, size_t>
1405{
1406    _LIBCPP_INLINE_VISIBILITY
1407    size_t operator()(unsigned long __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1408};
1409
1410template <>
1411struct _LIBCPP_TEMPLATE_VIS hash<long long>
1412    : public __scalar_hash<long long>
1413{
1414};
1415
1416template <>
1417struct _LIBCPP_TEMPLATE_VIS hash<unsigned long long>
1418    : public __scalar_hash<unsigned long long>
1419{
1420};
1421
1422#ifndef _LIBCPP_HAS_NO_INT128
1423
1424template <>
1425struct _LIBCPP_TEMPLATE_VIS hash<__int128_t>
1426    : public __scalar_hash<__int128_t>
1427{
1428};
1429
1430template <>
1431struct _LIBCPP_TEMPLATE_VIS hash<__uint128_t>
1432    : public __scalar_hash<__uint128_t>
1433{
1434};
1435
1436#endif
1437
1438template <>
1439struct _LIBCPP_TEMPLATE_VIS hash<float>
1440    : public __scalar_hash<float>
1441{
1442    _LIBCPP_INLINE_VISIBILITY
1443    size_t operator()(float __v) const _NOEXCEPT
1444    {
1445        // -0.0 and 0.0 should return same hash
1446       if (__v == 0)
1447           return 0;
1448        return __scalar_hash<float>::operator()(__v);
1449    }
1450};
1451
1452template <>
1453struct _LIBCPP_TEMPLATE_VIS hash<double>
1454    : public __scalar_hash<double>
1455{
1456    _LIBCPP_INLINE_VISIBILITY
1457    size_t operator()(double __v) const _NOEXCEPT
1458    {
1459        // -0.0 and 0.0 should return same hash
1460       if (__v == 0)
1461           return 0;
1462        return __scalar_hash<double>::operator()(__v);
1463    }
1464};
1465
1466template <>
1467struct _LIBCPP_TEMPLATE_VIS hash<long double>
1468    : public __scalar_hash<long double>
1469{
1470    _LIBCPP_INLINE_VISIBILITY
1471    size_t operator()(long double __v) const _NOEXCEPT
1472    {
1473        // -0.0 and 0.0 should return same hash
1474        if (__v == 0)
1475            return 0;
1476#if defined(__i386__)
1477        // Zero out padding bits
1478        union
1479        {
1480            long double __t;
1481            struct
1482            {
1483                size_t __a;
1484                size_t __b;
1485                size_t __c;
1486                size_t __d;
1487            } __s;
1488        } __u;
1489        __u.__s.__a = 0;
1490        __u.__s.__b = 0;
1491        __u.__s.__c = 0;
1492        __u.__s.__d = 0;
1493        __u.__t = __v;
1494        return __u.__s.__a ^ __u.__s.__b ^ __u.__s.__c ^ __u.__s.__d;
1495#elif defined(__x86_64__)
1496        // Zero out padding bits
1497        union
1498        {
1499            long double __t;
1500            struct
1501            {
1502                size_t __a;
1503                size_t __b;
1504            } __s;
1505        } __u;
1506        __u.__s.__a = 0;
1507        __u.__s.__b = 0;
1508        __u.__t = __v;
1509        return __u.__s.__a ^ __u.__s.__b;
1510#else
1511        return __scalar_hash<long double>::operator()(__v);
1512#endif
1513    }
1514};
1515
1516#if _LIBCPP_STD_VER > 11
1517
1518template <class _Tp, bool = is_enum<_Tp>::value>
1519struct _LIBCPP_TEMPLATE_VIS __enum_hash
1520    : public unary_function<_Tp, size_t>
1521{
1522    _LIBCPP_INLINE_VISIBILITY
1523    size_t operator()(_Tp __v) const _NOEXCEPT
1524    {
1525        typedef typename underlying_type<_Tp>::type type;
1526        return hash<type>{}(static_cast<type>(__v));
1527    }
1528};
1529template <class _Tp>
1530struct _LIBCPP_TEMPLATE_VIS __enum_hash<_Tp, false> {
1531    __enum_hash() = delete;
1532    __enum_hash(__enum_hash const&) = delete;
1533    __enum_hash& operator=(__enum_hash const&) = delete;
1534};
1535
1536template <class _Tp>
1537struct _LIBCPP_TEMPLATE_VIS hash : public __enum_hash<_Tp>
1538{
1539};
1540#endif
1541
1542#if _LIBCPP_STD_VER > 14
1543
1544template <>
1545struct _LIBCPP_TEMPLATE_VIS hash<nullptr_t>
1546  : public unary_function<nullptr_t, size_t>
1547{
1548  _LIBCPP_INLINE_VISIBILITY
1549  size_t operator()(nullptr_t) const _NOEXCEPT {
1550    return 662607004ull;
1551  }
1552};
1553#endif
1554
1555#ifndef _LIBCPP_CXX03_LANG
1556template <class _Key, class _Hash>
1557using __check_hash_requirements = integral_constant<bool,
1558    is_copy_constructible<_Hash>::value &&
1559    is_move_constructible<_Hash>::value &&
1560    __invokable_r<size_t, _Hash, _Key const&>::value
1561>;
1562
1563template <class _Key, class _Hash = std::hash<_Key> >
1564using __has_enabled_hash = integral_constant<bool,
1565    __check_hash_requirements<_Key, _Hash>::value &&
1566    is_default_constructible<_Hash>::value
1567>;
1568
1569#if _LIBCPP_STD_VER > 14
1570template <class _Type, class>
1571using __enable_hash_helper_imp = _Type;
1572
1573template <class _Type, class ..._Keys>
1574using __enable_hash_helper = __enable_hash_helper_imp<_Type,
1575  typename enable_if<__all<__has_enabled_hash<_Keys>::value...>::value>::type
1576>;
1577#else
1578template <class _Type, class ...>
1579using __enable_hash_helper = _Type;
1580#endif
1581
1582#endif // !_LIBCPP_CXX03_LANG
1583
1584_LIBCPP_END_NAMESPACE_STD
1585
1586#endif  // _LIBCPP_UTILITY
1587