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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_HAS_NO_RVALUE_REFERENCES
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_HAS_NO_RVALUE_REFERENCES
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_HAS_NO_CONSTEXPR) || 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_HAS_NO_RVALUE_REFERENCES
612
613
614template <class _Tp>
615struct __make_pair_return_impl
616{
617    typedef _Tp type;
618};
619
620template <class _Tp>
621struct __make_pair_return_impl<reference_wrapper<_Tp>>
622{
623    typedef _Tp& type;
624};
625
626template <class _Tp>
627struct __make_pair_return
628{
629    typedef typename __make_pair_return_impl<typename decay<_Tp>::type>::type type;
630};
631
632template <class _T1, class _T2>
633inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
634pair<typename __make_pair_return<_T1>::type, typename __make_pair_return<_T2>::type>
635make_pair(_T1&& __t1, _T2&& __t2)
636{
637    return pair<typename __make_pair_return<_T1>::type, typename __make_pair_return<_T2>::type>
638               (_VSTD::forward<_T1>(__t1), _VSTD::forward<_T2>(__t2));
639}
640
641#else  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
642
643template <class _T1, class _T2>
644inline _LIBCPP_INLINE_VISIBILITY
645pair<_T1,_T2>
646make_pair(_T1 __x, _T2 __y)
647{
648    return pair<_T1, _T2>(__x, __y);
649}
650
651#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
652
653template <class _T1, class _T2>
654  class _LIBCPP_TEMPLATE_VIS tuple_size<pair<_T1, _T2> >
655    : public integral_constant<size_t, 2> {};
656
657template <class _T1, class _T2>
658class _LIBCPP_TEMPLATE_VIS tuple_element<0, pair<_T1, _T2> >
659{
660public:
661    typedef _T1 type;
662};
663
664template <class _T1, class _T2>
665class _LIBCPP_TEMPLATE_VIS tuple_element<1, pair<_T1, _T2> >
666{
667public:
668    typedef _T2 type;
669};
670
671template <size_t _Ip> struct __get_pair;
672
673template <>
674struct __get_pair<0>
675{
676    template <class _T1, class _T2>
677    static
678    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
679    _T1&
680    get(pair<_T1, _T2>& __p) _NOEXCEPT {return __p.first;}
681
682    template <class _T1, class _T2>
683    static
684    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
685    const _T1&
686    get(const pair<_T1, _T2>& __p) _NOEXCEPT {return __p.first;}
687
688#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
689
690    template <class _T1, class _T2>
691    static
692    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
693    _T1&&
694    get(pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<_T1>(__p.first);}
695
696    template <class _T1, class _T2>
697    static
698    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
699    const _T1&&
700    get(const pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<const _T1>(__p.first);}
701
702#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
703};
704
705template <>
706struct __get_pair<1>
707{
708    template <class _T1, class _T2>
709    static
710    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
711    _T2&
712    get(pair<_T1, _T2>& __p) _NOEXCEPT {return __p.second;}
713
714    template <class _T1, class _T2>
715    static
716    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
717    const _T2&
718    get(const pair<_T1, _T2>& __p) _NOEXCEPT {return __p.second;}
719
720#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
721
722    template <class _T1, class _T2>
723    static
724    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
725    _T2&&
726    get(pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<_T2>(__p.second);}
727
728    template <class _T1, class _T2>
729    static
730    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
731    const _T2&&
732    get(const pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<const _T2>(__p.second);}
733
734#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
735};
736
737template <size_t _Ip, class _T1, class _T2>
738inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
739typename tuple_element<_Ip, pair<_T1, _T2> >::type&
740get(pair<_T1, _T2>& __p) _NOEXCEPT
741{
742    return __get_pair<_Ip>::get(__p);
743}
744
745template <size_t _Ip, class _T1, class _T2>
746inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
747const typename tuple_element<_Ip, pair<_T1, _T2> >::type&
748get(const pair<_T1, _T2>& __p) _NOEXCEPT
749{
750    return __get_pair<_Ip>::get(__p);
751}
752
753#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
754
755template <size_t _Ip, class _T1, class _T2>
756inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
757typename tuple_element<_Ip, pair<_T1, _T2> >::type&&
758get(pair<_T1, _T2>&& __p) _NOEXCEPT
759{
760    return __get_pair<_Ip>::get(_VSTD::move(__p));
761}
762
763template <size_t _Ip, class _T1, class _T2>
764inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
765const typename tuple_element<_Ip, pair<_T1, _T2> >::type&&
766get(const pair<_T1, _T2>&& __p) _NOEXCEPT
767{
768    return __get_pair<_Ip>::get(_VSTD::move(__p));
769}
770
771#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
772
773#if _LIBCPP_STD_VER > 11
774template <class _T1, class _T2>
775inline _LIBCPP_INLINE_VISIBILITY
776constexpr _T1 & get(pair<_T1, _T2>& __p) _NOEXCEPT
777{
778    return __get_pair<0>::get(__p);
779}
780
781template <class _T1, class _T2>
782inline _LIBCPP_INLINE_VISIBILITY
783constexpr _T1 const & get(pair<_T1, _T2> const& __p) _NOEXCEPT
784{
785    return __get_pair<0>::get(__p);
786}
787
788template <class _T1, class _T2>
789inline _LIBCPP_INLINE_VISIBILITY
790constexpr _T1 && get(pair<_T1, _T2>&& __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 const && get(pair<_T1, _T2> const&& __p) _NOEXCEPT
798{
799    return __get_pair<0>::get(_VSTD::move(__p));
800}
801
802template <class _T1, class _T2>
803inline _LIBCPP_INLINE_VISIBILITY
804constexpr _T1 & get(pair<_T2, _T1>& __p) _NOEXCEPT
805{
806    return __get_pair<1>::get(__p);
807}
808
809template <class _T1, class _T2>
810inline _LIBCPP_INLINE_VISIBILITY
811constexpr _T1 const & get(pair<_T2, _T1> const& __p) _NOEXCEPT
812{
813    return __get_pair<1>::get(__p);
814}
815
816template <class _T1, class _T2>
817inline _LIBCPP_INLINE_VISIBILITY
818constexpr _T1 && get(pair<_T2, _T1>&& __p) _NOEXCEPT
819{
820    return __get_pair<1>::get(_VSTD::move(__p));
821}
822
823template <class _T1, class _T2>
824inline _LIBCPP_INLINE_VISIBILITY
825constexpr _T1 const && get(pair<_T2, _T1> const&& __p) _NOEXCEPT
826{
827    return __get_pair<1>::get(_VSTD::move(__p));
828}
829
830#endif
831
832#if _LIBCPP_STD_VER > 11
833
834template<class _Tp, _Tp... _Ip>
835struct _LIBCPP_TEMPLATE_VIS integer_sequence
836{
837    typedef _Tp value_type;
838    static_assert( is_integral<_Tp>::value,
839                  "std::integer_sequence can only be instantiated with an integral type" );
840    static
841    _LIBCPP_INLINE_VISIBILITY
842    constexpr
843    size_t
844    size() noexcept { return sizeof...(_Ip); }
845};
846
847template<size_t... _Ip>
848    using index_sequence = integer_sequence<size_t, _Ip...>;
849
850#if __has_builtin(__make_integer_seq) && !defined(_LIBCPP_TESTING_FALLBACK_MAKE_INTEGER_SEQUENCE)
851
852template <class _Tp, _Tp _Ep>
853using __make_integer_sequence = __make_integer_seq<integer_sequence, _Tp, _Ep>;
854
855#else
856
857template<typename _Tp, _Tp _Np> using __make_integer_sequence_unchecked =
858  typename __detail::__make<_Np>::type::template __convert<integer_sequence, _Tp>;
859
860template <class _Tp, _Tp _Ep>
861struct __make_integer_sequence_checked
862{
863    static_assert(is_integral<_Tp>::value,
864                  "std::make_integer_sequence can only be instantiated with an integral type" );
865    static_assert(0 <= _Ep, "std::make_integer_sequence must have a non-negative sequence length");
866    // Workaround GCC bug by preventing bad installations when 0 <= _Ep
867    // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68929
868    typedef __make_integer_sequence_unchecked<_Tp, 0 <= _Ep ? _Ep : 0> type;
869};
870
871template <class _Tp, _Tp _Ep>
872using __make_integer_sequence = typename __make_integer_sequence_checked<_Tp, _Ep>::type;
873
874#endif
875
876template<class _Tp, _Tp _Np>
877    using make_integer_sequence = __make_integer_sequence<_Tp, _Np>;
878
879template<size_t _Np>
880    using make_index_sequence = make_integer_sequence<size_t, _Np>;
881
882template<class... _Tp>
883    using index_sequence_for = make_index_sequence<sizeof...(_Tp)>;
884
885#endif  // _LIBCPP_STD_VER > 11
886
887#if _LIBCPP_STD_VER > 11
888template<class _T1, class _T2 = _T1>
889inline _LIBCPP_INLINE_VISIBILITY
890_T1 exchange(_T1& __obj, _T2 && __new_value)
891{
892    _T1 __old_value = _VSTD::move(__obj);
893    __obj = _VSTD::forward<_T2>(__new_value);
894    return __old_value;
895}
896#endif  // _LIBCPP_STD_VER > 11
897
898#if _LIBCPP_STD_VER > 14
899
900struct _LIBCPP_TYPE_VIS in_place_t {
901    explicit in_place_t() = default;
902};
903#ifndef _LIBCPP_HAS_NO_INLINE_VARIABLES
904inline
905#endif
906constexpr in_place_t in_place{};
907
908template <class _Tp>
909struct _LIBCPP_TYPE_VIS in_place_type_t {
910    explicit in_place_type_t() = default;
911};
912template <class _Tp>
913#ifndef _LIBCPP_HAS_NO_INLINE_VARIABLES
914inline
915#endif
916constexpr in_place_type_t<_Tp> in_place_type{};
917
918template <size_t _Idx>
919struct _LIBCPP_TYPE_VIS in_place_index_t {
920    explicit in_place_index_t() = default;
921};
922template <size_t _Idx>
923#ifndef _LIBCPP_HAS_NO_INLINE_VARIABLES
924inline
925#endif
926constexpr in_place_index_t<_Idx> in_place_index{};
927
928template <class _Tp> struct __is_inplace_type_imp : false_type {};
929template <class _Tp> struct __is_inplace_type_imp<in_place_type_t<_Tp>> : true_type {};
930
931template <class _Tp>
932using __is_inplace_type = __is_inplace_type_imp<__uncvref_t<_Tp>>;
933
934#endif // _LIBCPP_STD_VER > 14
935
936template <class _Arg, class _Result>
937struct _LIBCPP_TEMPLATE_VIS unary_function
938{
939    typedef _Arg    argument_type;
940    typedef _Result result_type;
941};
942
943template <class _Size>
944inline _LIBCPP_INLINE_VISIBILITY
945_Size
946__loadword(const void* __p)
947{
948    _Size __r;
949    std::memcpy(&__r, __p, sizeof(__r));
950    return __r;
951}
952
953// We use murmur2 when size_t is 32 bits, and cityhash64 when size_t
954// is 64 bits.  This is because cityhash64 uses 64bit x 64bit
955// multiplication, which can be very slow on 32-bit systems.
956template <class _Size, size_t = sizeof(_Size)*__CHAR_BIT__>
957struct __murmur2_or_cityhash;
958
959template <class _Size>
960struct __murmur2_or_cityhash<_Size, 32>
961{
962    inline _Size operator()(const void* __key, _Size __len)
963         _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK;
964};
965
966// murmur2
967template <class _Size>
968_Size
969__murmur2_or_cityhash<_Size, 32>::operator()(const void* __key, _Size __len)
970{
971    const _Size __m = 0x5bd1e995;
972    const _Size __r = 24;
973    _Size __h = __len;
974    const unsigned char* __data = static_cast<const unsigned char*>(__key);
975    for (; __len >= 4; __data += 4, __len -= 4)
976    {
977        _Size __k = __loadword<_Size>(__data);
978        __k *= __m;
979        __k ^= __k >> __r;
980        __k *= __m;
981        __h *= __m;
982        __h ^= __k;
983    }
984    switch (__len)
985    {
986    case 3:
987        __h ^= __data[2] << 16;
988    case 2:
989        __h ^= __data[1] << 8;
990    case 1:
991        __h ^= __data[0];
992        __h *= __m;
993    }
994    __h ^= __h >> 13;
995    __h *= __m;
996    __h ^= __h >> 15;
997    return __h;
998}
999
1000template <class _Size>
1001struct __murmur2_or_cityhash<_Size, 64>
1002{
1003    inline _Size operator()(const void* __key, _Size __len)  _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK;
1004
1005 private:
1006  // Some primes between 2^63 and 2^64.
1007  static const _Size __k0 = 0xc3a5c85c97cb3127ULL;
1008  static const _Size __k1 = 0xb492b66fbe98f273ULL;
1009  static const _Size __k2 = 0x9ae16a3b2f90404fULL;
1010  static const _Size __k3 = 0xc949d7c7509e6557ULL;
1011
1012  static _Size __rotate(_Size __val, int __shift) {
1013    return __shift == 0 ? __val : ((__val >> __shift) | (__val << (64 - __shift)));
1014  }
1015
1016  static _Size __rotate_by_at_least_1(_Size __val, int __shift) {
1017    return (__val >> __shift) | (__val << (64 - __shift));
1018  }
1019
1020  static _Size __shift_mix(_Size __val) {
1021    return __val ^ (__val >> 47);
1022  }
1023
1024  static _Size __hash_len_16(_Size __u, _Size __v)
1025     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1026  {
1027    const _Size __mul = 0x9ddfea08eb382d69ULL;
1028    _Size __a = (__u ^ __v) * __mul;
1029    __a ^= (__a >> 47);
1030    _Size __b = (__v ^ __a) * __mul;
1031    __b ^= (__b >> 47);
1032    __b *= __mul;
1033    return __b;
1034  }
1035
1036  static _Size __hash_len_0_to_16(const char* __s, _Size __len)
1037     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1038  {
1039    if (__len > 8) {
1040      const _Size __a = __loadword<_Size>(__s);
1041      const _Size __b = __loadword<_Size>(__s + __len - 8);
1042      return __hash_len_16(__a, __rotate_by_at_least_1(__b + __len, __len)) ^ __b;
1043    }
1044    if (__len >= 4) {
1045      const uint32_t __a = __loadword<uint32_t>(__s);
1046      const uint32_t __b = __loadword<uint32_t>(__s + __len - 4);
1047      return __hash_len_16(__len + (__a << 3), __b);
1048    }
1049    if (__len > 0) {
1050      const unsigned char __a = __s[0];
1051      const unsigned char __b = __s[__len >> 1];
1052      const unsigned char __c = __s[__len - 1];
1053      const uint32_t __y = static_cast<uint32_t>(__a) +
1054                           (static_cast<uint32_t>(__b) << 8);
1055      const uint32_t __z = __len + (static_cast<uint32_t>(__c) << 2);
1056      return __shift_mix(__y * __k2 ^ __z * __k3) * __k2;
1057    }
1058    return __k2;
1059  }
1060
1061  static _Size __hash_len_17_to_32(const char *__s, _Size __len)
1062     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1063  {
1064    const _Size __a = __loadword<_Size>(__s) * __k1;
1065    const _Size __b = __loadword<_Size>(__s + 8);
1066    const _Size __c = __loadword<_Size>(__s + __len - 8) * __k2;
1067    const _Size __d = __loadword<_Size>(__s + __len - 16) * __k0;
1068    return __hash_len_16(__rotate(__a - __b, 43) + __rotate(__c, 30) + __d,
1069                         __a + __rotate(__b ^ __k3, 20) - __c + __len);
1070  }
1071
1072  // Return a 16-byte hash for 48 bytes.  Quick and dirty.
1073  // Callers do best to use "random-looking" values for a and b.
1074  static pair<_Size, _Size> __weak_hash_len_32_with_seeds(
1075      _Size __w, _Size __x, _Size __y, _Size __z, _Size __a, _Size __b)
1076        _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1077  {
1078    __a += __w;
1079    __b = __rotate(__b + __a + __z, 21);
1080    const _Size __c = __a;
1081    __a += __x;
1082    __a += __y;
1083    __b += __rotate(__a, 44);
1084    return pair<_Size, _Size>(__a + __z, __b + __c);
1085  }
1086
1087  // Return a 16-byte hash for s[0] ... s[31], a, and b.  Quick and dirty.
1088  static pair<_Size, _Size> __weak_hash_len_32_with_seeds(
1089      const char* __s, _Size __a, _Size __b)
1090    _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1091  {
1092    return __weak_hash_len_32_with_seeds(__loadword<_Size>(__s),
1093                                         __loadword<_Size>(__s + 8),
1094                                         __loadword<_Size>(__s + 16),
1095                                         __loadword<_Size>(__s + 24),
1096                                         __a,
1097                                         __b);
1098  }
1099
1100  // Return an 8-byte hash for 33 to 64 bytes.
1101  static _Size __hash_len_33_to_64(const char *__s, size_t __len)
1102    _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1103  {
1104    _Size __z = __loadword<_Size>(__s + 24);
1105    _Size __a = __loadword<_Size>(__s) +
1106                (__len + __loadword<_Size>(__s + __len - 16)) * __k0;
1107    _Size __b = __rotate(__a + __z, 52);
1108    _Size __c = __rotate(__a, 37);
1109    __a += __loadword<_Size>(__s + 8);
1110    __c += __rotate(__a, 7);
1111    __a += __loadword<_Size>(__s + 16);
1112    _Size __vf = __a + __z;
1113    _Size __vs = __b + __rotate(__a, 31) + __c;
1114    __a = __loadword<_Size>(__s + 16) + __loadword<_Size>(__s + __len - 32);
1115    __z += __loadword<_Size>(__s + __len - 8);
1116    __b = __rotate(__a + __z, 52);
1117    __c = __rotate(__a, 37);
1118    __a += __loadword<_Size>(__s + __len - 24);
1119    __c += __rotate(__a, 7);
1120    __a += __loadword<_Size>(__s + __len - 16);
1121    _Size __wf = __a + __z;
1122    _Size __ws = __b + __rotate(__a, 31) + __c;
1123    _Size __r = __shift_mix((__vf + __ws) * __k2 + (__wf + __vs) * __k0);
1124    return __shift_mix(__r * __k0 + __vs) * __k2;
1125  }
1126};
1127
1128// cityhash64
1129template <class _Size>
1130_Size
1131__murmur2_or_cityhash<_Size, 64>::operator()(const void* __key, _Size __len)
1132{
1133  const char* __s = static_cast<const char*>(__key);
1134  if (__len <= 32) {
1135    if (__len <= 16) {
1136      return __hash_len_0_to_16(__s, __len);
1137    } else {
1138      return __hash_len_17_to_32(__s, __len);
1139    }
1140  } else if (__len <= 64) {
1141    return __hash_len_33_to_64(__s, __len);
1142  }
1143
1144  // For strings over 64 bytes we hash the end first, and then as we
1145  // loop we keep 56 bytes of state: v, w, x, y, and z.
1146  _Size __x = __loadword<_Size>(__s + __len - 40);
1147  _Size __y = __loadword<_Size>(__s + __len - 16) +
1148              __loadword<_Size>(__s + __len - 56);
1149  _Size __z = __hash_len_16(__loadword<_Size>(__s + __len - 48) + __len,
1150                          __loadword<_Size>(__s + __len - 24));
1151  pair<_Size, _Size> __v = __weak_hash_len_32_with_seeds(__s + __len - 64, __len, __z);
1152  pair<_Size, _Size> __w = __weak_hash_len_32_with_seeds(__s + __len - 32, __y + __k1, __x);
1153  __x = __x * __k1 + __loadword<_Size>(__s);
1154
1155  // Decrease len to the nearest multiple of 64, and operate on 64-byte chunks.
1156  __len = (__len - 1) & ~static_cast<_Size>(63);
1157  do {
1158    __x = __rotate(__x + __y + __v.first + __loadword<_Size>(__s + 8), 37) * __k1;
1159    __y = __rotate(__y + __v.second + __loadword<_Size>(__s + 48), 42) * __k1;
1160    __x ^= __w.second;
1161    __y += __v.first + __loadword<_Size>(__s + 40);
1162    __z = __rotate(__z + __w.first, 33) * __k1;
1163    __v = __weak_hash_len_32_with_seeds(__s, __v.second * __k1, __x + __w.first);
1164    __w = __weak_hash_len_32_with_seeds(__s + 32, __z + __w.second,
1165                                        __y + __loadword<_Size>(__s + 16));
1166    std::swap(__z, __x);
1167    __s += 64;
1168    __len -= 64;
1169  } while (__len != 0);
1170  return __hash_len_16(
1171      __hash_len_16(__v.first, __w.first) + __shift_mix(__y) * __k1 + __z,
1172      __hash_len_16(__v.second, __w.second) + __x);
1173}
1174
1175template <class _Tp, size_t = sizeof(_Tp) / sizeof(size_t)>
1176struct __scalar_hash;
1177
1178template <class _Tp>
1179struct __scalar_hash<_Tp, 0>
1180    : public unary_function<_Tp, size_t>
1181{
1182    _LIBCPP_INLINE_VISIBILITY
1183    size_t operator()(_Tp __v) const _NOEXCEPT
1184    {
1185        union
1186        {
1187            _Tp    __t;
1188            size_t __a;
1189        } __u;
1190        __u.__a = 0;
1191        __u.__t = __v;
1192        return __u.__a;
1193    }
1194};
1195
1196template <class _Tp>
1197struct __scalar_hash<_Tp, 1>
1198    : public unary_function<_Tp, size_t>
1199{
1200    _LIBCPP_INLINE_VISIBILITY
1201    size_t operator()(_Tp __v) const _NOEXCEPT
1202    {
1203        union
1204        {
1205            _Tp    __t;
1206            size_t __a;
1207        } __u;
1208        __u.__t = __v;
1209        return __u.__a;
1210    }
1211};
1212
1213template <class _Tp>
1214struct __scalar_hash<_Tp, 2>
1215    : public unary_function<_Tp, size_t>
1216{
1217    _LIBCPP_INLINE_VISIBILITY
1218    size_t operator()(_Tp __v) const _NOEXCEPT
1219    {
1220        union
1221        {
1222            _Tp __t;
1223            struct
1224            {
1225                size_t __a;
1226                size_t __b;
1227            } __s;
1228        } __u;
1229        __u.__t = __v;
1230        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
1231    }
1232};
1233
1234template <class _Tp>
1235struct __scalar_hash<_Tp, 3>
1236    : public unary_function<_Tp, size_t>
1237{
1238    _LIBCPP_INLINE_VISIBILITY
1239    size_t operator()(_Tp __v) const _NOEXCEPT
1240    {
1241        union
1242        {
1243            _Tp __t;
1244            struct
1245            {
1246                size_t __a;
1247                size_t __b;
1248                size_t __c;
1249            } __s;
1250        } __u;
1251        __u.__t = __v;
1252        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
1253    }
1254};
1255
1256template <class _Tp>
1257struct __scalar_hash<_Tp, 4>
1258    : public unary_function<_Tp, size_t>
1259{
1260    _LIBCPP_INLINE_VISIBILITY
1261    size_t operator()(_Tp __v) const _NOEXCEPT
1262    {
1263        union
1264        {
1265            _Tp __t;
1266            struct
1267            {
1268                size_t __a;
1269                size_t __b;
1270                size_t __c;
1271                size_t __d;
1272            } __s;
1273        } __u;
1274        __u.__t = __v;
1275        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
1276    }
1277};
1278
1279struct _PairT {
1280  size_t first;
1281  size_t second;
1282};
1283
1284_LIBCPP_INLINE_VISIBILITY
1285inline size_t __hash_combine(size_t __lhs, size_t __rhs) _NOEXCEPT {
1286    typedef __scalar_hash<_PairT> _HashT;
1287    const _PairT __p = {__lhs, __rhs};
1288    return _HashT()(__p);
1289}
1290
1291template<class _Tp>
1292struct _LIBCPP_TEMPLATE_VIS hash<_Tp*>
1293    : public unary_function<_Tp*, size_t>
1294{
1295    _LIBCPP_INLINE_VISIBILITY
1296    size_t operator()(_Tp* __v) const _NOEXCEPT
1297    {
1298        union
1299        {
1300            _Tp* __t;
1301            size_t __a;
1302        } __u;
1303        __u.__t = __v;
1304        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
1305    }
1306};
1307
1308
1309template <>
1310struct _LIBCPP_TEMPLATE_VIS hash<bool>
1311    : public unary_function<bool, size_t>
1312{
1313    _LIBCPP_INLINE_VISIBILITY
1314    size_t operator()(bool __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1315};
1316
1317template <>
1318struct _LIBCPP_TEMPLATE_VIS hash<char>
1319    : public unary_function<char, size_t>
1320{
1321    _LIBCPP_INLINE_VISIBILITY
1322    size_t operator()(char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1323};
1324
1325template <>
1326struct _LIBCPP_TEMPLATE_VIS hash<signed char>
1327    : public unary_function<signed char, size_t>
1328{
1329    _LIBCPP_INLINE_VISIBILITY
1330    size_t operator()(signed char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1331};
1332
1333template <>
1334struct _LIBCPP_TEMPLATE_VIS hash<unsigned char>
1335    : public unary_function<unsigned char, size_t>
1336{
1337    _LIBCPP_INLINE_VISIBILITY
1338    size_t operator()(unsigned char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1339};
1340
1341#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
1342
1343template <>
1344struct _LIBCPP_TEMPLATE_VIS hash<char16_t>
1345    : public unary_function<char16_t, size_t>
1346{
1347    _LIBCPP_INLINE_VISIBILITY
1348    size_t operator()(char16_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1349};
1350
1351template <>
1352struct _LIBCPP_TEMPLATE_VIS hash<char32_t>
1353    : public unary_function<char32_t, size_t>
1354{
1355    _LIBCPP_INLINE_VISIBILITY
1356    size_t operator()(char32_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1357};
1358
1359#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
1360
1361template <>
1362struct _LIBCPP_TEMPLATE_VIS hash<wchar_t>
1363    : public unary_function<wchar_t, size_t>
1364{
1365    _LIBCPP_INLINE_VISIBILITY
1366    size_t operator()(wchar_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1367};
1368
1369template <>
1370struct _LIBCPP_TEMPLATE_VIS hash<short>
1371    : public unary_function<short, size_t>
1372{
1373    _LIBCPP_INLINE_VISIBILITY
1374    size_t operator()(short __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1375};
1376
1377template <>
1378struct _LIBCPP_TEMPLATE_VIS hash<unsigned short>
1379    : public unary_function<unsigned short, size_t>
1380{
1381    _LIBCPP_INLINE_VISIBILITY
1382    size_t operator()(unsigned short __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1383};
1384
1385template <>
1386struct _LIBCPP_TEMPLATE_VIS hash<int>
1387    : public unary_function<int, size_t>
1388{
1389    _LIBCPP_INLINE_VISIBILITY
1390    size_t operator()(int __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1391};
1392
1393template <>
1394struct _LIBCPP_TEMPLATE_VIS hash<unsigned int>
1395    : public unary_function<unsigned int, size_t>
1396{
1397    _LIBCPP_INLINE_VISIBILITY
1398    size_t operator()(unsigned int __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1399};
1400
1401template <>
1402struct _LIBCPP_TEMPLATE_VIS hash<long>
1403    : public unary_function<long, size_t>
1404{
1405    _LIBCPP_INLINE_VISIBILITY
1406    size_t operator()(long __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1407};
1408
1409template <>
1410struct _LIBCPP_TEMPLATE_VIS hash<unsigned long>
1411    : public unary_function<unsigned long, size_t>
1412{
1413    _LIBCPP_INLINE_VISIBILITY
1414    size_t operator()(unsigned long __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1415};
1416
1417template <>
1418struct _LIBCPP_TEMPLATE_VIS hash<long long>
1419    : public __scalar_hash<long long>
1420{
1421};
1422
1423template <>
1424struct _LIBCPP_TEMPLATE_VIS hash<unsigned long long>
1425    : public __scalar_hash<unsigned long long>
1426{
1427};
1428
1429#ifndef _LIBCPP_HAS_NO_INT128
1430
1431template <>
1432struct _LIBCPP_TEMPLATE_VIS hash<__int128_t>
1433    : public __scalar_hash<__int128_t>
1434{
1435};
1436
1437template <>
1438struct _LIBCPP_TEMPLATE_VIS hash<__uint128_t>
1439    : public __scalar_hash<__uint128_t>
1440{
1441};
1442
1443#endif
1444
1445template <>
1446struct _LIBCPP_TEMPLATE_VIS hash<float>
1447    : public __scalar_hash<float>
1448{
1449    _LIBCPP_INLINE_VISIBILITY
1450    size_t operator()(float __v) const _NOEXCEPT
1451    {
1452        // -0.0 and 0.0 should return same hash
1453       if (__v == 0)
1454           return 0;
1455        return __scalar_hash<float>::operator()(__v);
1456    }
1457};
1458
1459template <>
1460struct _LIBCPP_TEMPLATE_VIS hash<double>
1461    : public __scalar_hash<double>
1462{
1463    _LIBCPP_INLINE_VISIBILITY
1464    size_t operator()(double __v) const _NOEXCEPT
1465    {
1466        // -0.0 and 0.0 should return same hash
1467       if (__v == 0)
1468           return 0;
1469        return __scalar_hash<double>::operator()(__v);
1470    }
1471};
1472
1473template <>
1474struct _LIBCPP_TEMPLATE_VIS hash<long double>
1475    : public __scalar_hash<long double>
1476{
1477    _LIBCPP_INLINE_VISIBILITY
1478    size_t operator()(long double __v) const _NOEXCEPT
1479    {
1480        // -0.0 and 0.0 should return same hash
1481        if (__v == 0)
1482            return 0;
1483#if defined(__i386__)
1484        // Zero out padding bits
1485        union
1486        {
1487            long double __t;
1488            struct
1489            {
1490                size_t __a;
1491                size_t __b;
1492                size_t __c;
1493                size_t __d;
1494            } __s;
1495        } __u;
1496        __u.__s.__a = 0;
1497        __u.__s.__b = 0;
1498        __u.__s.__c = 0;
1499        __u.__s.__d = 0;
1500        __u.__t = __v;
1501        return __u.__s.__a ^ __u.__s.__b ^ __u.__s.__c ^ __u.__s.__d;
1502#elif defined(__x86_64__)
1503        // Zero out padding bits
1504        union
1505        {
1506            long double __t;
1507            struct
1508            {
1509                size_t __a;
1510                size_t __b;
1511            } __s;
1512        } __u;
1513        __u.__s.__a = 0;
1514        __u.__s.__b = 0;
1515        __u.__t = __v;
1516        return __u.__s.__a ^ __u.__s.__b;
1517#else
1518        return __scalar_hash<long double>::operator()(__v);
1519#endif
1520    }
1521};
1522
1523#if _LIBCPP_STD_VER > 11
1524
1525template <class _Tp, bool = is_enum<_Tp>::value>
1526struct _LIBCPP_TEMPLATE_VIS __enum_hash
1527    : public unary_function<_Tp, size_t>
1528{
1529    _LIBCPP_INLINE_VISIBILITY
1530    size_t operator()(_Tp __v) const _NOEXCEPT
1531    {
1532        typedef typename underlying_type<_Tp>::type type;
1533        return hash<type>{}(static_cast<type>(__v));
1534    }
1535};
1536template <class _Tp>
1537struct _LIBCPP_TEMPLATE_VIS __enum_hash<_Tp, false> {
1538    __enum_hash() = delete;
1539    __enum_hash(__enum_hash const&) = delete;
1540    __enum_hash& operator=(__enum_hash const&) = delete;
1541};
1542
1543template <class _Tp>
1544struct _LIBCPP_TEMPLATE_VIS hash : public __enum_hash<_Tp>
1545{
1546};
1547#endif
1548
1549#if _LIBCPP_STD_VER > 14
1550
1551template <>
1552struct _LIBCPP_TEMPLATE_VIS hash<nullptr_t>
1553  : public unary_function<nullptr_t, size_t>
1554{
1555  _LIBCPP_INLINE_VISIBILITY
1556  size_t operator()(nullptr_t) const _NOEXCEPT {
1557    return 662607004ull;
1558  }
1559};
1560#endif
1561
1562#ifndef _LIBCPP_CXX03_LANG
1563template <class _Key, class _Hash>
1564using __check_hash_requirements = integral_constant<bool,
1565    is_copy_constructible<_Hash>::value &&
1566    is_move_constructible<_Hash>::value &&
1567    __invokable_r<size_t, _Hash, _Key const&>::value
1568>;
1569
1570template <class _Key, class _Hash = std::hash<_Key> >
1571using __has_enabled_hash = integral_constant<bool,
1572    __check_hash_requirements<_Key, _Hash>::value &&
1573    is_default_constructible<_Hash>::value
1574>;
1575
1576#if _LIBCPP_STD_VER > 14
1577template <class _Type, class>
1578using __enable_hash_helper_imp = _Type;
1579
1580template <class _Type, class ..._Keys>
1581using __enable_hash_helper = __enable_hash_helper_imp<_Type,
1582  typename enable_if<__all<__has_enabled_hash<_Keys>::value...>::value>::type
1583>;
1584#else
1585template <class _Type, class ...>
1586using __enable_hash_helper = _Type;
1587#endif
1588
1589#endif // !_LIBCPP_CXX03_LANG
1590
1591_LIBCPP_END_NAMESPACE_STD
1592
1593#endif  // _LIBCPP_UTILITY
1594