xref: /freebsd-12.1/contrib/libc++/include/utility (revision 514bfd46)
1// -*- C++ -*-
2//===-------------------------- utility -----------------------------------===//
3//
4//                     The LLVM Compiler Infrastructure
5//
6// This file is dual licensed under the MIT and the University of Illinois Open
7// Source Licenses. See LICENSE.TXT for details.
8//
9//===----------------------------------------------------------------------===//
10
11#ifndef _LIBCPP_UTILITY
12#define _LIBCPP_UTILITY
13
14/*
15    utility synopsis
16
17#include <initializer_list>
18
19namespace std
20{
21
22template <class T>
23    void
24    swap(T& a, T& b);
25
26namespace rel_ops
27{
28    template<class T> bool operator!=(const T&, const T&);
29    template<class T> bool operator> (const T&, const T&);
30    template<class T> bool operator<=(const T&, const T&);
31    template<class T> bool operator>=(const T&, const T&);
32}
33
34template<class T>
35void
36swap(T& a, T& b) noexcept(is_nothrow_move_constructible<T>::value &&
37                          is_nothrow_move_assignable<T>::value);
38
39template <class T, size_t N>
40void
41swap(T (&a)[N], T (&b)[N]) noexcept(noexcept(swap(*a, *b)));
42
43template <class T> T&& forward(typename remove_reference<T>::type& t) noexcept;  // constexpr in C++14
44template <class T> T&& forward(typename remove_reference<T>::type&& t) noexcept; // constexpr in C++14
45
46template <class T> typename remove_reference<T>::type&& move(T&&) noexcept;      // constexpr in C++14
47
48template <class T>
49    typename conditional
50    <
51        !is_nothrow_move_constructible<T>::value && is_copy_constructible<T>::value,
52        const T&,
53        T&&
54    >::type
55    move_if_noexcept(T& x) noexcept; // constexpr in C++14
56
57template <class T> constexpr add_const_t<T>& as_const(T& t) noexcept;      // C++17
58template <class T>                      void as_const(const T&&) = delete; // C++17
59
60template <class T> typename add_rvalue_reference<T>::type declval() noexcept;
61
62template <class T1, class T2>
63struct pair
64{
65    typedef T1 first_type;
66    typedef T2 second_type;
67
68    T1 first;
69    T2 second;
70
71    pair(const pair&) = default;
72    pair(pair&&) = default;
73    constexpr pair();
74    pair(const T1& x, const T2& y);                          // constexpr in C++14
75    template <class U, class V> pair(U&& x, V&& y);          // constexpr in C++14
76    template <class U, class V> pair(const pair<U, V>& p);   // constexpr in C++14
77    template <class U, class V> pair(pair<U, V>&& p);        // constexpr in C++14
78    template <class... Args1, class... Args2>
79        pair(piecewise_construct_t, tuple<Args1...> first_args,
80             tuple<Args2...> second_args);
81
82    template <class U, class V> pair& operator=(const pair<U, V>& p);
83    pair& operator=(pair&& p) noexcept(is_nothrow_move_assignable<T1>::value &&
84                                       is_nothrow_move_assignable<T2>::value);
85    template <class U, class V> pair& operator=(pair<U, V>&& p);
86
87    void swap(pair& p) noexcept(is_nothrow_swappable_v<T1> &&
88                                is_nothrow_swappable_v<T2>);
89};
90
91template <class T1, class T2> bool operator==(const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
92template <class T1, class T2> bool operator!=(const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
93template <class T1, class T2> bool operator< (const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
94template <class T1, class T2> bool operator> (const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
95template <class T1, class T2> bool operator>=(const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
96template <class T1, class T2> bool operator<=(const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
97
98template <class T1, class T2> pair<V1, V2> make_pair(T1&&, T2&&);   // constexpr in C++14
99template <class T1, class T2>
100void
101swap(pair<T1, T2>& x, pair<T1, T2>& y) noexcept(noexcept(x.swap(y)));
102
103struct piecewise_construct_t { };
104inline constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
105
106template <class T> struct tuple_size;
107template <size_t I, class T> class tuple_element;
108
109template <class T1, class T2> struct tuple_size<pair<T1, T2> >;
110template <class T1, class T2> struct tuple_element<0, pair<T1, T2> >;
111template <class T1, class T2> struct tuple_element<1, pair<T1, T2> >;
112
113template<size_t I, class T1, class T2>
114    typename tuple_element<I, pair<T1, T2> >::type&
115    get(pair<T1, T2>&) noexcept; // constexpr in C++14
116
117template<size_t I, class T1, class T2>
118    const typename tuple_element<I, pair<T1, T2> >::type&
119    get(const pair<T1, T2>&) noexcept; // constexpr in C++14
120
121template<size_t I, class T1, class T2>
122    typename tuple_element<I, pair<T1, T2> >::type&&
123    get(pair<T1, T2>&&) noexcept; // constexpr in C++14
124
125template<size_t I, class T1, class T2>
126    const typename tuple_element<I, pair<T1, T2> >::type&&
127    get(const pair<T1, T2>&&) noexcept; // constexpr in C++14
128
129template<class T1, class T2>
130    constexpr T1& get(pair<T1, T2>&) noexcept; // C++14
131
132template<class T1, class T2>
133    constexpr const T1& get(const pair<T1, T2>&) noexcept; // C++14
134
135template<class T1, class T2>
136    constexpr T1&& get(pair<T1, T2>&&) noexcept; // C++14
137
138template<class T1, class T2>
139    constexpr const T1&& get(const pair<T1, T2>&&) noexcept; // C++14
140
141template<class T1, class T2>
142    constexpr T1& get(pair<T2, T1>&) noexcept; // C++14
143
144template<class T1, class T2>
145    constexpr const T1& get(const pair<T2, T1>&) noexcept; // C++14
146
147template<class T1, class T2>
148    constexpr T1&& get(pair<T2, T1>&&) noexcept; // C++14
149
150template<class T1, class T2>
151    constexpr const T1&& get(const pair<T2, T1>&&) noexcept; // C++14
152
153// C++14
154
155template<class T, T... I>
156struct integer_sequence
157{
158    typedef T value_type;
159
160    static constexpr size_t size() noexcept;
161};
162
163template<size_t... I>
164  using index_sequence = integer_sequence<size_t, I...>;
165
166template<class T, T N>
167  using make_integer_sequence = integer_sequence<T, 0, 1, ..., N-1>;
168template<size_t N>
169  using make_index_sequence = make_integer_sequence<size_t, N>;
170
171template<class... T>
172  using index_sequence_for = make_index_sequence<sizeof...(T)>;
173
174template<class T, class U=T>
175    T exchange(T& obj, U&& new_value);
176
177// 20.2.7, in-place construction // C++17
178struct in_place_t {
179  explicit in_place_t() = default;
180};
181inline constexpr in_place_t in_place{};
182template <class T>
183  struct in_place_type_t {
184    explicit in_place_type_t() = default;
185  };
186template <class T>
187  inline constexpr in_place_type_t<T> in_place_type{};
188template <size_t I>
189  struct in_place_index_t {
190    explicit in_place_index_t() = default;
191  };
192template <size_t I>
193  inline constexpr in_place_index_t<I> in_place_index{};
194
195}  // std
196
197*/
198
199#include <__config>
200#include <__tuple>
201#include <type_traits>
202#include <initializer_list>
203#include <cstddef>
204#include <cstring>
205#include <cstdint>
206#include <version>
207#include <__debug>
208
209#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
210#pragma GCC system_header
211#endif
212
213_LIBCPP_BEGIN_NAMESPACE_STD
214
215namespace rel_ops
216{
217
218template<class _Tp>
219inline _LIBCPP_INLINE_VISIBILITY
220bool
221operator!=(const _Tp& __x, const _Tp& __y)
222{
223    return !(__x == __y);
224}
225
226template<class _Tp>
227inline _LIBCPP_INLINE_VISIBILITY
228bool
229operator> (const _Tp& __x, const _Tp& __y)
230{
231    return __y < __x;
232}
233
234template<class _Tp>
235inline _LIBCPP_INLINE_VISIBILITY
236bool
237operator<=(const _Tp& __x, const _Tp& __y)
238{
239    return !(__y < __x);
240}
241
242template<class _Tp>
243inline _LIBCPP_INLINE_VISIBILITY
244bool
245operator>=(const _Tp& __x, const _Tp& __y)
246{
247    return !(__x < __y);
248}
249
250}  // rel_ops
251
252// swap_ranges
253
254
255template <class _ForwardIterator1, class _ForwardIterator2>
256inline _LIBCPP_INLINE_VISIBILITY
257_ForwardIterator2
258swap_ranges(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2)
259{
260    for(; __first1 != __last1; ++__first1, (void) ++__first2)
261        swap(*__first1, *__first2);
262    return __first2;
263}
264
265// forward declared in <type_traits>
266template<class _Tp, size_t _Np>
267inline _LIBCPP_INLINE_VISIBILITY
268typename enable_if<
269    __is_swappable<_Tp>::value
270>::type
271swap(_Tp (&__a)[_Np], _Tp (&__b)[_Np]) _NOEXCEPT_(__is_nothrow_swappable<_Tp>::value)
272{
273    _VSTD::swap_ranges(__a, __a + _Np, __b);
274}
275
276template <class _Tp>
277inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
278#ifndef _LIBCPP_CXX03_LANG
279typename conditional
280<
281    !is_nothrow_move_constructible<_Tp>::value && is_copy_constructible<_Tp>::value,
282    const _Tp&,
283    _Tp&&
284>::type
285#else  // _LIBCPP_CXX03_LANG
286const _Tp&
287#endif
288move_if_noexcept(_Tp& __x) _NOEXCEPT
289{
290    return _VSTD::move(__x);
291}
292
293#if _LIBCPP_STD_VER > 14
294template <class _Tp> constexpr add_const_t<_Tp>& as_const(_Tp& __t) noexcept { return __t; }
295template <class _Tp>                        void as_const(const _Tp&&) = delete;
296#endif
297
298struct _LIBCPP_TEMPLATE_VIS piecewise_construct_t { };
299#if defined(_LIBCPP_CXX03_LANG) || defined(_LIBCPP_BUILDING_LIBRARY)
300extern _LIBCPP_EXPORTED_FROM_ABI const piecewise_construct_t piecewise_construct;// = piecewise_construct_t();
301#else
302/* _LIBCPP_INLINE_VAR */ constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
303#endif
304
305#if defined(_LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR)
306template <class, class>
307struct __non_trivially_copyable_base {
308  _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
309  __non_trivially_copyable_base() _NOEXCEPT {}
310  _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
311  __non_trivially_copyable_base(__non_trivially_copyable_base const&) _NOEXCEPT {}
312};
313#endif
314
315template <class _T1, class _T2>
316struct _LIBCPP_TEMPLATE_VIS pair
317#if defined(_LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR)
318: private __non_trivially_copyable_base<_T1, _T2>
319#endif
320{
321    typedef _T1 first_type;
322    typedef _T2 second_type;
323
324    _T1 first;
325    _T2 second;
326
327#if !defined(_LIBCPP_CXX03_LANG)
328    pair(pair const&) = default;
329    pair(pair&&) = default;
330#else
331  // Use the implicitly declared copy constructor in C++03
332#endif
333
334#ifdef _LIBCPP_CXX03_LANG
335    _LIBCPP_INLINE_VISIBILITY
336    pair() : first(), second() {}
337
338    _LIBCPP_INLINE_VISIBILITY
339    pair(_T1 const& __t1, _T2 const& __t2) : first(__t1), second(__t2) {}
340
341    template <class _U1, class _U2>
342    _LIBCPP_INLINE_VISIBILITY
343    pair(const pair<_U1, _U2>& __p) : first(__p.first), second(__p.second) {}
344
345    _LIBCPP_INLINE_VISIBILITY
346    pair& operator=(pair const& __p) {
347        first = __p.first;
348        second = __p.second;
349        return *this;
350    }
351#else
352    template <bool _Val>
353    using _EnableB = typename enable_if<_Val, bool>::type;
354
355    struct _CheckArgs {
356      template <class _U1, class _U2>
357      static constexpr bool __enable_default() {
358          return is_default_constructible<_U1>::value
359              && is_default_constructible<_U2>::value;
360      }
361
362      template <class _U1, class _U2>
363      static constexpr bool __enable_explicit() {
364          return is_constructible<first_type, _U1>::value
365              && is_constructible<second_type, _U2>::value
366              && (!is_convertible<_U1, first_type>::value
367                  || !is_convertible<_U2, second_type>::value);
368      }
369
370      template <class _U1, class _U2>
371      static constexpr bool __enable_implicit() {
372          return is_constructible<first_type, _U1>::value
373              && is_constructible<second_type, _U2>::value
374              && is_convertible<_U1, first_type>::value
375              && is_convertible<_U2, second_type>::value;
376      }
377    };
378
379    template <bool _MaybeEnable>
380    using _CheckArgsDep = typename conditional<
381      _MaybeEnable, _CheckArgs, __check_tuple_constructor_fail>::type;
382
383    struct _CheckTupleLikeConstructor {
384        template <class _Tuple>
385        static constexpr bool __enable_implicit() {
386            return __tuple_convertible<_Tuple, pair>::value;
387        }
388
389        template <class _Tuple>
390        static constexpr bool __enable_explicit() {
391            return __tuple_constructible<_Tuple, pair>::value
392               && !__tuple_convertible<_Tuple, pair>::value;
393        }
394
395        template <class _Tuple>
396        static constexpr bool __enable_assign() {
397            return __tuple_assignable<_Tuple, pair>::value;
398        }
399    };
400
401    template <class _Tuple>
402    using _CheckTLC = typename conditional<
403        __tuple_like_with_size<_Tuple, 2>::value
404            && !is_same<typename decay<_Tuple>::type, pair>::value,
405        _CheckTupleLikeConstructor,
406        __check_tuple_constructor_fail
407    >::type;
408
409    template<bool _Dummy = true, _EnableB<
410            _CheckArgsDep<_Dummy>::template __enable_default<_T1, _T2>()
411    > = false>
412    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
413    pair() _NOEXCEPT_(is_nothrow_default_constructible<first_type>::value &&
414                      is_nothrow_default_constructible<second_type>::value)
415        : first(), second() {}
416
417    template <bool _Dummy = true, _EnableB<
418             _CheckArgsDep<_Dummy>::template __enable_explicit<_T1 const&, _T2 const&>()
419    > = false>
420    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
421    explicit pair(_T1 const& __t1, _T2 const& __t2)
422        _NOEXCEPT_(is_nothrow_copy_constructible<first_type>::value &&
423                   is_nothrow_copy_constructible<second_type>::value)
424        : first(__t1), second(__t2) {}
425
426    template<bool _Dummy = true, _EnableB<
427            _CheckArgsDep<_Dummy>::template __enable_implicit<_T1 const&, _T2 const&>()
428    > = false>
429    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
430    pair(_T1 const& __t1, _T2 const& __t2)
431        _NOEXCEPT_(is_nothrow_copy_constructible<first_type>::value &&
432                   is_nothrow_copy_constructible<second_type>::value)
433        : first(__t1), second(__t2) {}
434
435    template<class _U1, class _U2, _EnableB<
436             _CheckArgs::template __enable_explicit<_U1, _U2>()
437    > = false>
438    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
439    explicit pair(_U1&& __u1, _U2&& __u2)
440        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1>::value &&
441                    is_nothrow_constructible<second_type, _U2>::value))
442        : first(_VSTD::forward<_U1>(__u1)), second(_VSTD::forward<_U2>(__u2)) {}
443
444    template<class _U1, class _U2, _EnableB<
445            _CheckArgs::template __enable_implicit<_U1, _U2>()
446    > = false>
447    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
448    pair(_U1&& __u1, _U2&& __u2)
449        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1>::value &&
450                    is_nothrow_constructible<second_type, _U2>::value))
451        : first(_VSTD::forward<_U1>(__u1)), second(_VSTD::forward<_U2>(__u2)) {}
452
453    template<class _U1, class _U2, _EnableB<
454            _CheckArgs::template __enable_explicit<_U1 const&, _U2 const&>()
455    > = false>
456    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
457    explicit pair(pair<_U1, _U2> const& __p)
458        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1 const&>::value &&
459                    is_nothrow_constructible<second_type, _U2 const&>::value))
460        : first(__p.first), second(__p.second) {}
461
462    template<class _U1, class _U2, _EnableB<
463            _CheckArgs::template __enable_implicit<_U1 const&, _U2 const&>()
464    > = false>
465    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
466    pair(pair<_U1, _U2> const& __p)
467        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1 const&>::value &&
468                    is_nothrow_constructible<second_type, _U2 const&>::value))
469        : first(__p.first), second(__p.second) {}
470
471    template<class _U1, class _U2, _EnableB<
472            _CheckArgs::template __enable_explicit<_U1, _U2>()
473    > = false>
474    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
475    explicit pair(pair<_U1, _U2>&&__p)
476        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1&&>::value &&
477                    is_nothrow_constructible<second_type, _U2&&>::value))
478        : first(_VSTD::forward<_U1>(__p.first)), second(_VSTD::forward<_U2>(__p.second)) {}
479
480    template<class _U1, class _U2, _EnableB<
481            _CheckArgs::template __enable_implicit<_U1, _U2>()
482    > = false>
483    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
484    pair(pair<_U1, _U2>&& __p)
485        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1&&>::value &&
486                    is_nothrow_constructible<second_type, _U2&&>::value))
487        : first(_VSTD::forward<_U1>(__p.first)), second(_VSTD::forward<_U2>(__p.second)) {}
488
489    template<class _Tuple, _EnableB<
490            _CheckTLC<_Tuple>::template __enable_explicit<_Tuple>()
491    > = false>
492    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
493    explicit pair(_Tuple&& __p)
494        : first(_VSTD::get<0>(_VSTD::forward<_Tuple>(__p))),
495          second(_VSTD::get<1>(_VSTD::forward<_Tuple>(__p))) {}
496
497    template<class _Tuple, _EnableB<
498            _CheckTLC<_Tuple>::template __enable_implicit<_Tuple>()
499    > = false>
500    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
501    pair(_Tuple&& __p)
502        : first(_VSTD::get<0>(_VSTD::forward<_Tuple>(__p))),
503          second(_VSTD::get<1>(_VSTD::forward<_Tuple>(__p))) {}
504
505    template <class... _Args1, class... _Args2>
506    _LIBCPP_INLINE_VISIBILITY
507    pair(piecewise_construct_t __pc,
508         tuple<_Args1...> __first_args, tuple<_Args2...> __second_args)
509        _NOEXCEPT_((is_nothrow_constructible<first_type, _Args1...>::value &&
510                    is_nothrow_constructible<second_type, _Args2...>::value))
511        : pair(__pc, __first_args, __second_args,
512                typename __make_tuple_indices<sizeof...(_Args1)>::type(),
513                typename __make_tuple_indices<sizeof...(_Args2) >::type()) {}
514
515    _LIBCPP_INLINE_VISIBILITY
516    pair& operator=(typename conditional<
517                        is_copy_assignable<first_type>::value &&
518                        is_copy_assignable<second_type>::value,
519                    pair, __nat>::type const& __p)
520        _NOEXCEPT_(is_nothrow_copy_assignable<first_type>::value &&
521                   is_nothrow_copy_assignable<second_type>::value)
522    {
523        first = __p.first;
524        second = __p.second;
525        return *this;
526    }
527
528    _LIBCPP_INLINE_VISIBILITY
529    pair& operator=(typename conditional<
530                        is_move_assignable<first_type>::value &&
531                        is_move_assignable<second_type>::value,
532                    pair, __nat>::type&& __p)
533        _NOEXCEPT_(is_nothrow_move_assignable<first_type>::value &&
534                   is_nothrow_move_assignable<second_type>::value)
535    {
536        first = _VSTD::forward<first_type>(__p.first);
537        second = _VSTD::forward<second_type>(__p.second);
538        return *this;
539    }
540
541    template <class _Tuple, _EnableB<
542            _CheckTLC<_Tuple>::template __enable_assign<_Tuple>()
543     > = false>
544    _LIBCPP_INLINE_VISIBILITY
545    pair& operator=(_Tuple&& __p) {
546        first = _VSTD::get<0>(_VSTD::forward<_Tuple>(__p));
547        second = _VSTD::get<1>(_VSTD::forward<_Tuple>(__p));
548        return *this;
549    }
550#endif
551
552    _LIBCPP_INLINE_VISIBILITY
553    void
554    swap(pair& __p) _NOEXCEPT_(__is_nothrow_swappable<first_type>::value &&
555                               __is_nothrow_swappable<second_type>::value)
556    {
557        using _VSTD::swap;
558        swap(first,  __p.first);
559        swap(second, __p.second);
560    }
561private:
562
563#ifndef _LIBCPP_CXX03_LANG
564    template <class... _Args1, class... _Args2, size_t... _I1, size_t... _I2>
565        _LIBCPP_INLINE_VISIBILITY
566        pair(piecewise_construct_t,
567             tuple<_Args1...>& __first_args, tuple<_Args2...>& __second_args,
568             __tuple_indices<_I1...>, __tuple_indices<_I2...>);
569#endif
570};
571
572#ifndef _LIBCPP_HAS_NO_DEDUCTION_GUIDES
573template<class _T1, class _T2>
574pair(_T1, _T2) -> pair<_T1, _T2>;
575#endif // _LIBCPP_HAS_NO_DEDUCTION_GUIDES
576
577template <class _T1, class _T2>
578inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
579bool
580operator==(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
581{
582    return __x.first == __y.first && __x.second == __y.second;
583}
584
585template <class _T1, class _T2>
586inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
587bool
588operator!=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
589{
590    return !(__x == __y);
591}
592
593template <class _T1, class _T2>
594inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
595bool
596operator< (const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
597{
598    return __x.first < __y.first || (!(__y.first < __x.first) && __x.second < __y.second);
599}
600
601template <class _T1, class _T2>
602inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
603bool
604operator> (const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
605{
606    return __y < __x;
607}
608
609template <class _T1, class _T2>
610inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
611bool
612operator>=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
613{
614    return !(__x < __y);
615}
616
617template <class _T1, class _T2>
618inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
619bool
620operator<=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
621{
622    return !(__y < __x);
623}
624
625template <class _T1, class _T2>
626inline _LIBCPP_INLINE_VISIBILITY
627typename enable_if
628<
629    __is_swappable<_T1>::value &&
630    __is_swappable<_T2>::value,
631    void
632>::type
633swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y)
634                     _NOEXCEPT_((__is_nothrow_swappable<_T1>::value &&
635                                 __is_nothrow_swappable<_T2>::value))
636{
637    __x.swap(__y);
638}
639
640template <class _Tp>
641struct __unwrap_reference { typedef _Tp type; };
642
643template <class _Tp>
644struct __unwrap_reference<reference_wrapper<_Tp> > { typedef _Tp& type; };
645
646#if _LIBCPP_STD_VER > 17
647template <class _Tp>
648struct unwrap_reference : __unwrap_reference<_Tp> { };
649
650template <class _Tp>
651struct unwrap_ref_decay : unwrap_reference<typename decay<_Tp>::type> { };
652#endif // > C++17
653
654template <class _Tp>
655struct __unwrap_ref_decay
656#if _LIBCPP_STD_VER > 17
657    : unwrap_ref_decay<_Tp>
658#else
659    : __unwrap_reference<typename decay<_Tp>::type>
660#endif
661{ };
662
663#ifndef _LIBCPP_CXX03_LANG
664
665template <class _T1, class _T2>
666inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
667pair<typename __unwrap_ref_decay<_T1>::type, typename __unwrap_ref_decay<_T2>::type>
668make_pair(_T1&& __t1, _T2&& __t2)
669{
670    return pair<typename __unwrap_ref_decay<_T1>::type, typename __unwrap_ref_decay<_T2>::type>
671               (_VSTD::forward<_T1>(__t1), _VSTD::forward<_T2>(__t2));
672}
673
674#else  // _LIBCPP_CXX03_LANG
675
676template <class _T1, class _T2>
677inline _LIBCPP_INLINE_VISIBILITY
678pair<_T1,_T2>
679make_pair(_T1 __x, _T2 __y)
680{
681    return pair<_T1, _T2>(__x, __y);
682}
683
684#endif  // _LIBCPP_CXX03_LANG
685
686template <class _T1, class _T2>
687  struct _LIBCPP_TEMPLATE_VIS tuple_size<pair<_T1, _T2> >
688    : public integral_constant<size_t, 2> {};
689
690template <size_t _Ip, class _T1, class _T2>
691class _LIBCPP_TEMPLATE_VIS tuple_element<_Ip, pair<_T1, _T2> >
692{
693    static_assert(_Ip < 2, "Index out of bounds in std::tuple_element<std::pair<T1, T2>>");
694};
695
696template <class _T1, class _T2>
697class _LIBCPP_TEMPLATE_VIS tuple_element<0, pair<_T1, _T2> >
698{
699public:
700    typedef _T1 type;
701};
702
703template <class _T1, class _T2>
704class _LIBCPP_TEMPLATE_VIS tuple_element<1, pair<_T1, _T2> >
705{
706public:
707    typedef _T2 type;
708};
709
710template <size_t _Ip> struct __get_pair;
711
712template <>
713struct __get_pair<0>
714{
715    template <class _T1, class _T2>
716    static
717    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
718    _T1&
719    get(pair<_T1, _T2>& __p) _NOEXCEPT {return __p.first;}
720
721    template <class _T1, class _T2>
722    static
723    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
724    const _T1&
725    get(const pair<_T1, _T2>& __p) _NOEXCEPT {return __p.first;}
726
727#ifndef _LIBCPP_CXX03_LANG
728    template <class _T1, class _T2>
729    static
730    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
731    _T1&&
732    get(pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<_T1>(__p.first);}
733
734    template <class _T1, class _T2>
735    static
736    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
737    const _T1&&
738    get(const pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<const _T1>(__p.first);}
739#endif  // _LIBCPP_CXX03_LANG
740};
741
742template <>
743struct __get_pair<1>
744{
745    template <class _T1, class _T2>
746    static
747    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
748    _T2&
749    get(pair<_T1, _T2>& __p) _NOEXCEPT {return __p.second;}
750
751    template <class _T1, class _T2>
752    static
753    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
754    const _T2&
755    get(const pair<_T1, _T2>& __p) _NOEXCEPT {return __p.second;}
756
757#ifndef _LIBCPP_CXX03_LANG
758    template <class _T1, class _T2>
759    static
760    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
761    _T2&&
762    get(pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<_T2>(__p.second);}
763
764    template <class _T1, class _T2>
765    static
766    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
767    const _T2&&
768    get(const pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<const _T2>(__p.second);}
769#endif  // _LIBCPP_CXX03_LANG
770};
771
772template <size_t _Ip, class _T1, class _T2>
773inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
774typename tuple_element<_Ip, pair<_T1, _T2> >::type&
775get(pair<_T1, _T2>& __p) _NOEXCEPT
776{
777    return __get_pair<_Ip>::get(__p);
778}
779
780template <size_t _Ip, class _T1, class _T2>
781inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
782const typename tuple_element<_Ip, pair<_T1, _T2> >::type&
783get(const pair<_T1, _T2>& __p) _NOEXCEPT
784{
785    return __get_pair<_Ip>::get(__p);
786}
787
788#ifndef _LIBCPP_CXX03_LANG
789template <size_t _Ip, class _T1, class _T2>
790inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
791typename tuple_element<_Ip, pair<_T1, _T2> >::type&&
792get(pair<_T1, _T2>&& __p) _NOEXCEPT
793{
794    return __get_pair<_Ip>::get(_VSTD::move(__p));
795}
796
797template <size_t _Ip, class _T1, class _T2>
798inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
799const typename tuple_element<_Ip, pair<_T1, _T2> >::type&&
800get(const pair<_T1, _T2>&& __p) _NOEXCEPT
801{
802    return __get_pair<_Ip>::get(_VSTD::move(__p));
803}
804#endif  // _LIBCPP_CXX03_LANG
805
806#if _LIBCPP_STD_VER > 11
807template <class _T1, class _T2>
808inline _LIBCPP_INLINE_VISIBILITY
809constexpr _T1 & get(pair<_T1, _T2>& __p) _NOEXCEPT
810{
811    return __get_pair<0>::get(__p);
812}
813
814template <class _T1, class _T2>
815inline _LIBCPP_INLINE_VISIBILITY
816constexpr _T1 const & get(pair<_T1, _T2> const& __p) _NOEXCEPT
817{
818    return __get_pair<0>::get(__p);
819}
820
821template <class _T1, class _T2>
822inline _LIBCPP_INLINE_VISIBILITY
823constexpr _T1 && get(pair<_T1, _T2>&& __p) _NOEXCEPT
824{
825    return __get_pair<0>::get(_VSTD::move(__p));
826}
827
828template <class _T1, class _T2>
829inline _LIBCPP_INLINE_VISIBILITY
830constexpr _T1 const && get(pair<_T1, _T2> const&& __p) _NOEXCEPT
831{
832    return __get_pair<0>::get(_VSTD::move(__p));
833}
834
835template <class _T1, class _T2>
836inline _LIBCPP_INLINE_VISIBILITY
837constexpr _T1 & get(pair<_T2, _T1>& __p) _NOEXCEPT
838{
839    return __get_pair<1>::get(__p);
840}
841
842template <class _T1, class _T2>
843inline _LIBCPP_INLINE_VISIBILITY
844constexpr _T1 const & get(pair<_T2, _T1> const& __p) _NOEXCEPT
845{
846    return __get_pair<1>::get(__p);
847}
848
849template <class _T1, class _T2>
850inline _LIBCPP_INLINE_VISIBILITY
851constexpr _T1 && get(pair<_T2, _T1>&& __p) _NOEXCEPT
852{
853    return __get_pair<1>::get(_VSTD::move(__p));
854}
855
856template <class _T1, class _T2>
857inline _LIBCPP_INLINE_VISIBILITY
858constexpr _T1 const && get(pair<_T2, _T1> const&& __p) _NOEXCEPT
859{
860    return __get_pair<1>::get(_VSTD::move(__p));
861}
862
863#endif
864
865#if _LIBCPP_STD_VER > 11
866
867template<class _Tp, _Tp... _Ip>
868struct _LIBCPP_TEMPLATE_VIS integer_sequence
869{
870    typedef _Tp value_type;
871    static_assert( is_integral<_Tp>::value,
872                  "std::integer_sequence can only be instantiated with an integral type" );
873    static
874    _LIBCPP_INLINE_VISIBILITY
875    constexpr
876    size_t
877    size() noexcept { return sizeof...(_Ip); }
878};
879
880template<size_t... _Ip>
881    using index_sequence = integer_sequence<size_t, _Ip...>;
882
883#if __has_builtin(__make_integer_seq) && !defined(_LIBCPP_TESTING_FALLBACK_MAKE_INTEGER_SEQUENCE)
884
885template <class _Tp, _Tp _Ep>
886using __make_integer_sequence = __make_integer_seq<integer_sequence, _Tp, _Ep>;
887
888#else
889
890template<typename _Tp, _Tp _Np> using __make_integer_sequence_unchecked =
891  typename __detail::__make<_Np>::type::template __convert<integer_sequence, _Tp>;
892
893template <class _Tp, _Tp _Ep>
894struct __make_integer_sequence_checked
895{
896    static_assert(is_integral<_Tp>::value,
897                  "std::make_integer_sequence can only be instantiated with an integral type" );
898    static_assert(0 <= _Ep, "std::make_integer_sequence must have a non-negative sequence length");
899    // Workaround GCC bug by preventing bad installations when 0 <= _Ep
900    // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68929
901    typedef __make_integer_sequence_unchecked<_Tp, 0 <= _Ep ? _Ep : 0> type;
902};
903
904template <class _Tp, _Tp _Ep>
905using __make_integer_sequence = typename __make_integer_sequence_checked<_Tp, _Ep>::type;
906
907#endif
908
909template<class _Tp, _Tp _Np>
910    using make_integer_sequence = __make_integer_sequence<_Tp, _Np>;
911
912template<size_t _Np>
913    using make_index_sequence = make_integer_sequence<size_t, _Np>;
914
915template<class... _Tp>
916    using index_sequence_for = make_index_sequence<sizeof...(_Tp)>;
917
918#endif  // _LIBCPP_STD_VER > 11
919
920#if _LIBCPP_STD_VER > 11
921template<class _T1, class _T2 = _T1>
922inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
923_T1 exchange(_T1& __obj, _T2 && __new_value)
924{
925    _T1 __old_value = _VSTD::move(__obj);
926    __obj = _VSTD::forward<_T2>(__new_value);
927    return __old_value;
928}
929#endif  // _LIBCPP_STD_VER > 11
930
931#if _LIBCPP_STD_VER > 14
932
933struct _LIBCPP_TYPE_VIS in_place_t {
934    explicit in_place_t() = default;
935};
936_LIBCPP_INLINE_VAR constexpr in_place_t in_place{};
937
938template <class _Tp>
939struct _LIBCPP_TEMPLATE_VIS in_place_type_t {
940    explicit in_place_type_t() = default;
941};
942template <class _Tp>
943_LIBCPP_INLINE_VAR constexpr in_place_type_t<_Tp> in_place_type{};
944
945template <size_t _Idx>
946struct _LIBCPP_TYPE_VIS in_place_index_t {
947    explicit in_place_index_t() = default;
948};
949template <size_t _Idx>
950_LIBCPP_INLINE_VAR constexpr in_place_index_t<_Idx> in_place_index{};
951
952template <class _Tp> struct __is_inplace_type_imp : false_type {};
953template <class _Tp> struct __is_inplace_type_imp<in_place_type_t<_Tp>> : true_type {};
954
955template <class _Tp>
956using __is_inplace_type = __is_inplace_type_imp<__uncvref_t<_Tp>>;
957
958template <class _Tp> struct __is_inplace_index_imp : false_type {};
959template <size_t _Idx> struct __is_inplace_index_imp<in_place_index_t<_Idx>> : true_type {};
960
961template <class _Tp>
962using __is_inplace_index = __is_inplace_index_imp<__uncvref_t<_Tp>>;
963
964#endif // _LIBCPP_STD_VER > 14
965
966template <class _Arg, class _Result>
967struct _LIBCPP_TEMPLATE_VIS unary_function
968{
969    typedef _Arg    argument_type;
970    typedef _Result result_type;
971};
972
973template <class _Size>
974inline _LIBCPP_INLINE_VISIBILITY
975_Size
976__loadword(const void* __p)
977{
978    _Size __r;
979    std::memcpy(&__r, __p, sizeof(__r));
980    return __r;
981}
982
983// We use murmur2 when size_t is 32 bits, and cityhash64 when size_t
984// is 64 bits.  This is because cityhash64 uses 64bit x 64bit
985// multiplication, which can be very slow on 32-bit systems.
986template <class _Size, size_t = sizeof(_Size)*__CHAR_BIT__>
987struct __murmur2_or_cityhash;
988
989template <class _Size>
990struct __murmur2_or_cityhash<_Size, 32>
991{
992    inline _Size operator()(const void* __key, _Size __len)
993         _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK;
994};
995
996// murmur2
997template <class _Size>
998_Size
999__murmur2_or_cityhash<_Size, 32>::operator()(const void* __key, _Size __len)
1000{
1001    const _Size __m = 0x5bd1e995;
1002    const _Size __r = 24;
1003    _Size __h = __len;
1004    const unsigned char* __data = static_cast<const unsigned char*>(__key);
1005    for (; __len >= 4; __data += 4, __len -= 4)
1006    {
1007        _Size __k = __loadword<_Size>(__data);
1008        __k *= __m;
1009        __k ^= __k >> __r;
1010        __k *= __m;
1011        __h *= __m;
1012        __h ^= __k;
1013    }
1014    switch (__len)
1015    {
1016    case 3:
1017        __h ^= __data[2] << 16;
1018        _LIBCPP_FALLTHROUGH();
1019    case 2:
1020        __h ^= __data[1] << 8;
1021        _LIBCPP_FALLTHROUGH();
1022    case 1:
1023        __h ^= __data[0];
1024        __h *= __m;
1025    }
1026    __h ^= __h >> 13;
1027    __h *= __m;
1028    __h ^= __h >> 15;
1029    return __h;
1030}
1031
1032template <class _Size>
1033struct __murmur2_or_cityhash<_Size, 64>
1034{
1035    inline _Size operator()(const void* __key, _Size __len)  _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK;
1036
1037 private:
1038  // Some primes between 2^63 and 2^64.
1039  static const _Size __k0 = 0xc3a5c85c97cb3127ULL;
1040  static const _Size __k1 = 0xb492b66fbe98f273ULL;
1041  static const _Size __k2 = 0x9ae16a3b2f90404fULL;
1042  static const _Size __k3 = 0xc949d7c7509e6557ULL;
1043
1044  static _Size __rotate(_Size __val, int __shift) {
1045    return __shift == 0 ? __val : ((__val >> __shift) | (__val << (64 - __shift)));
1046  }
1047
1048  static _Size __rotate_by_at_least_1(_Size __val, int __shift) {
1049    return (__val >> __shift) | (__val << (64 - __shift));
1050  }
1051
1052  static _Size __shift_mix(_Size __val) {
1053    return __val ^ (__val >> 47);
1054  }
1055
1056  static _Size __hash_len_16(_Size __u, _Size __v)
1057     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1058  {
1059    const _Size __mul = 0x9ddfea08eb382d69ULL;
1060    _Size __a = (__u ^ __v) * __mul;
1061    __a ^= (__a >> 47);
1062    _Size __b = (__v ^ __a) * __mul;
1063    __b ^= (__b >> 47);
1064    __b *= __mul;
1065    return __b;
1066  }
1067
1068  static _Size __hash_len_0_to_16(const char* __s, _Size __len)
1069     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1070  {
1071    if (__len > 8) {
1072      const _Size __a = __loadword<_Size>(__s);
1073      const _Size __b = __loadword<_Size>(__s + __len - 8);
1074      return __hash_len_16(__a, __rotate_by_at_least_1(__b + __len, __len)) ^ __b;
1075    }
1076    if (__len >= 4) {
1077      const uint32_t __a = __loadword<uint32_t>(__s);
1078      const uint32_t __b = __loadword<uint32_t>(__s + __len - 4);
1079      return __hash_len_16(__len + (__a << 3), __b);
1080    }
1081    if (__len > 0) {
1082      const unsigned char __a = __s[0];
1083      const unsigned char __b = __s[__len >> 1];
1084      const unsigned char __c = __s[__len - 1];
1085      const uint32_t __y = static_cast<uint32_t>(__a) +
1086                           (static_cast<uint32_t>(__b) << 8);
1087      const uint32_t __z = __len + (static_cast<uint32_t>(__c) << 2);
1088      return __shift_mix(__y * __k2 ^ __z * __k3) * __k2;
1089    }
1090    return __k2;
1091  }
1092
1093  static _Size __hash_len_17_to_32(const char *__s, _Size __len)
1094     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1095  {
1096    const _Size __a = __loadword<_Size>(__s) * __k1;
1097    const _Size __b = __loadword<_Size>(__s + 8);
1098    const _Size __c = __loadword<_Size>(__s + __len - 8) * __k2;
1099    const _Size __d = __loadword<_Size>(__s + __len - 16) * __k0;
1100    return __hash_len_16(__rotate(__a - __b, 43) + __rotate(__c, 30) + __d,
1101                         __a + __rotate(__b ^ __k3, 20) - __c + __len);
1102  }
1103
1104  // Return a 16-byte hash for 48 bytes.  Quick and dirty.
1105  // Callers do best to use "random-looking" values for a and b.
1106  static pair<_Size, _Size> __weak_hash_len_32_with_seeds(
1107      _Size __w, _Size __x, _Size __y, _Size __z, _Size __a, _Size __b)
1108        _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1109  {
1110    __a += __w;
1111    __b = __rotate(__b + __a + __z, 21);
1112    const _Size __c = __a;
1113    __a += __x;
1114    __a += __y;
1115    __b += __rotate(__a, 44);
1116    return pair<_Size, _Size>(__a + __z, __b + __c);
1117  }
1118
1119  // Return a 16-byte hash for s[0] ... s[31], a, and b.  Quick and dirty.
1120  static pair<_Size, _Size> __weak_hash_len_32_with_seeds(
1121      const char* __s, _Size __a, _Size __b)
1122    _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1123  {
1124    return __weak_hash_len_32_with_seeds(__loadword<_Size>(__s),
1125                                         __loadword<_Size>(__s + 8),
1126                                         __loadword<_Size>(__s + 16),
1127                                         __loadword<_Size>(__s + 24),
1128                                         __a,
1129                                         __b);
1130  }
1131
1132  // Return an 8-byte hash for 33 to 64 bytes.
1133  static _Size __hash_len_33_to_64(const char *__s, size_t __len)
1134    _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1135  {
1136    _Size __z = __loadword<_Size>(__s + 24);
1137    _Size __a = __loadword<_Size>(__s) +
1138                (__len + __loadword<_Size>(__s + __len - 16)) * __k0;
1139    _Size __b = __rotate(__a + __z, 52);
1140    _Size __c = __rotate(__a, 37);
1141    __a += __loadword<_Size>(__s + 8);
1142    __c += __rotate(__a, 7);
1143    __a += __loadword<_Size>(__s + 16);
1144    _Size __vf = __a + __z;
1145    _Size __vs = __b + __rotate(__a, 31) + __c;
1146    __a = __loadword<_Size>(__s + 16) + __loadword<_Size>(__s + __len - 32);
1147    __z += __loadword<_Size>(__s + __len - 8);
1148    __b = __rotate(__a + __z, 52);
1149    __c = __rotate(__a, 37);
1150    __a += __loadword<_Size>(__s + __len - 24);
1151    __c += __rotate(__a, 7);
1152    __a += __loadword<_Size>(__s + __len - 16);
1153    _Size __wf = __a + __z;
1154    _Size __ws = __b + __rotate(__a, 31) + __c;
1155    _Size __r = __shift_mix((__vf + __ws) * __k2 + (__wf + __vs) * __k0);
1156    return __shift_mix(__r * __k0 + __vs) * __k2;
1157  }
1158};
1159
1160// cityhash64
1161template <class _Size>
1162_Size
1163__murmur2_or_cityhash<_Size, 64>::operator()(const void* __key, _Size __len)
1164{
1165  const char* __s = static_cast<const char*>(__key);
1166  if (__len <= 32) {
1167    if (__len <= 16) {
1168      return __hash_len_0_to_16(__s, __len);
1169    } else {
1170      return __hash_len_17_to_32(__s, __len);
1171    }
1172  } else if (__len <= 64) {
1173    return __hash_len_33_to_64(__s, __len);
1174  }
1175
1176  // For strings over 64 bytes we hash the end first, and then as we
1177  // loop we keep 56 bytes of state: v, w, x, y, and z.
1178  _Size __x = __loadword<_Size>(__s + __len - 40);
1179  _Size __y = __loadword<_Size>(__s + __len - 16) +
1180              __loadword<_Size>(__s + __len - 56);
1181  _Size __z = __hash_len_16(__loadword<_Size>(__s + __len - 48) + __len,
1182                          __loadword<_Size>(__s + __len - 24));
1183  pair<_Size, _Size> __v = __weak_hash_len_32_with_seeds(__s + __len - 64, __len, __z);
1184  pair<_Size, _Size> __w = __weak_hash_len_32_with_seeds(__s + __len - 32, __y + __k1, __x);
1185  __x = __x * __k1 + __loadword<_Size>(__s);
1186
1187  // Decrease len to the nearest multiple of 64, and operate on 64-byte chunks.
1188  __len = (__len - 1) & ~static_cast<_Size>(63);
1189  do {
1190    __x = __rotate(__x + __y + __v.first + __loadword<_Size>(__s + 8), 37) * __k1;
1191    __y = __rotate(__y + __v.second + __loadword<_Size>(__s + 48), 42) * __k1;
1192    __x ^= __w.second;
1193    __y += __v.first + __loadword<_Size>(__s + 40);
1194    __z = __rotate(__z + __w.first, 33) * __k1;
1195    __v = __weak_hash_len_32_with_seeds(__s, __v.second * __k1, __x + __w.first);
1196    __w = __weak_hash_len_32_with_seeds(__s + 32, __z + __w.second,
1197                                        __y + __loadword<_Size>(__s + 16));
1198    std::swap(__z, __x);
1199    __s += 64;
1200    __len -= 64;
1201  } while (__len != 0);
1202  return __hash_len_16(
1203      __hash_len_16(__v.first, __w.first) + __shift_mix(__y) * __k1 + __z,
1204      __hash_len_16(__v.second, __w.second) + __x);
1205}
1206
1207template <class _Tp, size_t = sizeof(_Tp) / sizeof(size_t)>
1208struct __scalar_hash;
1209
1210template <class _Tp>
1211struct __scalar_hash<_Tp, 0>
1212    : public unary_function<_Tp, size_t>
1213{
1214    _LIBCPP_INLINE_VISIBILITY
1215    size_t operator()(_Tp __v) const _NOEXCEPT
1216    {
1217        union
1218        {
1219            _Tp    __t;
1220            size_t __a;
1221        } __u;
1222        __u.__a = 0;
1223        __u.__t = __v;
1224        return __u.__a;
1225    }
1226};
1227
1228template <class _Tp>
1229struct __scalar_hash<_Tp, 1>
1230    : public unary_function<_Tp, size_t>
1231{
1232    _LIBCPP_INLINE_VISIBILITY
1233    size_t operator()(_Tp __v) const _NOEXCEPT
1234    {
1235        union
1236        {
1237            _Tp    __t;
1238            size_t __a;
1239        } __u;
1240        __u.__t = __v;
1241        return __u.__a;
1242    }
1243};
1244
1245template <class _Tp>
1246struct __scalar_hash<_Tp, 2>
1247    : public unary_function<_Tp, size_t>
1248{
1249    _LIBCPP_INLINE_VISIBILITY
1250    size_t operator()(_Tp __v) const _NOEXCEPT
1251    {
1252        union
1253        {
1254            _Tp __t;
1255            struct
1256            {
1257                size_t __a;
1258                size_t __b;
1259            } __s;
1260        } __u;
1261        __u.__t = __v;
1262        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
1263    }
1264};
1265
1266template <class _Tp>
1267struct __scalar_hash<_Tp, 3>
1268    : public unary_function<_Tp, size_t>
1269{
1270    _LIBCPP_INLINE_VISIBILITY
1271    size_t operator()(_Tp __v) const _NOEXCEPT
1272    {
1273        union
1274        {
1275            _Tp __t;
1276            struct
1277            {
1278                size_t __a;
1279                size_t __b;
1280                size_t __c;
1281            } __s;
1282        } __u;
1283        __u.__t = __v;
1284        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
1285    }
1286};
1287
1288template <class _Tp>
1289struct __scalar_hash<_Tp, 4>
1290    : public unary_function<_Tp, size_t>
1291{
1292    _LIBCPP_INLINE_VISIBILITY
1293    size_t operator()(_Tp __v) const _NOEXCEPT
1294    {
1295        union
1296        {
1297            _Tp __t;
1298            struct
1299            {
1300                size_t __a;
1301                size_t __b;
1302                size_t __c;
1303                size_t __d;
1304            } __s;
1305        } __u;
1306        __u.__t = __v;
1307        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
1308    }
1309};
1310
1311struct _PairT {
1312  size_t first;
1313  size_t second;
1314};
1315
1316_LIBCPP_INLINE_VISIBILITY
1317inline size_t __hash_combine(size_t __lhs, size_t __rhs) _NOEXCEPT {
1318    typedef __scalar_hash<_PairT> _HashT;
1319    const _PairT __p = {__lhs, __rhs};
1320    return _HashT()(__p);
1321}
1322
1323template<class _Tp>
1324struct _LIBCPP_TEMPLATE_VIS hash<_Tp*>
1325    : public unary_function<_Tp*, size_t>
1326{
1327    _LIBCPP_INLINE_VISIBILITY
1328    size_t operator()(_Tp* __v) const _NOEXCEPT
1329    {
1330        union
1331        {
1332            _Tp* __t;
1333            size_t __a;
1334        } __u;
1335        __u.__t = __v;
1336        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
1337    }
1338};
1339
1340
1341template <>
1342struct _LIBCPP_TEMPLATE_VIS hash<bool>
1343    : public unary_function<bool, size_t>
1344{
1345    _LIBCPP_INLINE_VISIBILITY
1346    size_t operator()(bool __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1347};
1348
1349template <>
1350struct _LIBCPP_TEMPLATE_VIS hash<char>
1351    : public unary_function<char, size_t>
1352{
1353    _LIBCPP_INLINE_VISIBILITY
1354    size_t operator()(char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1355};
1356
1357template <>
1358struct _LIBCPP_TEMPLATE_VIS hash<signed char>
1359    : public unary_function<signed char, size_t>
1360{
1361    _LIBCPP_INLINE_VISIBILITY
1362    size_t operator()(signed char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1363};
1364
1365template <>
1366struct _LIBCPP_TEMPLATE_VIS hash<unsigned char>
1367    : public unary_function<unsigned char, size_t>
1368{
1369    _LIBCPP_INLINE_VISIBILITY
1370    size_t operator()(unsigned char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1371};
1372
1373#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
1374
1375template <>
1376struct _LIBCPP_TEMPLATE_VIS hash<char16_t>
1377    : public unary_function<char16_t, size_t>
1378{
1379    _LIBCPP_INLINE_VISIBILITY
1380    size_t operator()(char16_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1381};
1382
1383template <>
1384struct _LIBCPP_TEMPLATE_VIS hash<char32_t>
1385    : public unary_function<char32_t, size_t>
1386{
1387    _LIBCPP_INLINE_VISIBILITY
1388    size_t operator()(char32_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1389};
1390
1391#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
1392
1393template <>
1394struct _LIBCPP_TEMPLATE_VIS hash<wchar_t>
1395    : public unary_function<wchar_t, size_t>
1396{
1397    _LIBCPP_INLINE_VISIBILITY
1398    size_t operator()(wchar_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1399};
1400
1401template <>
1402struct _LIBCPP_TEMPLATE_VIS hash<short>
1403    : public unary_function<short, size_t>
1404{
1405    _LIBCPP_INLINE_VISIBILITY
1406    size_t operator()(short __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1407};
1408
1409template <>
1410struct _LIBCPP_TEMPLATE_VIS hash<unsigned short>
1411    : public unary_function<unsigned short, size_t>
1412{
1413    _LIBCPP_INLINE_VISIBILITY
1414    size_t operator()(unsigned short __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1415};
1416
1417template <>
1418struct _LIBCPP_TEMPLATE_VIS hash<int>
1419    : public unary_function<int, size_t>
1420{
1421    _LIBCPP_INLINE_VISIBILITY
1422    size_t operator()(int __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1423};
1424
1425template <>
1426struct _LIBCPP_TEMPLATE_VIS hash<unsigned int>
1427    : public unary_function<unsigned int, size_t>
1428{
1429    _LIBCPP_INLINE_VISIBILITY
1430    size_t operator()(unsigned int __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1431};
1432
1433template <>
1434struct _LIBCPP_TEMPLATE_VIS hash<long>
1435    : public unary_function<long, size_t>
1436{
1437    _LIBCPP_INLINE_VISIBILITY
1438    size_t operator()(long __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1439};
1440
1441template <>
1442struct _LIBCPP_TEMPLATE_VIS hash<unsigned long>
1443    : public unary_function<unsigned long, size_t>
1444{
1445    _LIBCPP_INLINE_VISIBILITY
1446    size_t operator()(unsigned long __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1447};
1448
1449template <>
1450struct _LIBCPP_TEMPLATE_VIS hash<long long>
1451    : public __scalar_hash<long long>
1452{
1453};
1454
1455template <>
1456struct _LIBCPP_TEMPLATE_VIS hash<unsigned long long>
1457    : public __scalar_hash<unsigned long long>
1458{
1459};
1460
1461#ifndef _LIBCPP_HAS_NO_INT128
1462
1463template <>
1464struct _LIBCPP_TEMPLATE_VIS hash<__int128_t>
1465    : public __scalar_hash<__int128_t>
1466{
1467};
1468
1469template <>
1470struct _LIBCPP_TEMPLATE_VIS hash<__uint128_t>
1471    : public __scalar_hash<__uint128_t>
1472{
1473};
1474
1475#endif
1476
1477template <>
1478struct _LIBCPP_TEMPLATE_VIS hash<float>
1479    : public __scalar_hash<float>
1480{
1481    _LIBCPP_INLINE_VISIBILITY
1482    size_t operator()(float __v) const _NOEXCEPT
1483    {
1484        // -0.0 and 0.0 should return same hash
1485       if (__v == 0.0)
1486           return 0;
1487        return __scalar_hash<float>::operator()(__v);
1488    }
1489};
1490
1491template <>
1492struct _LIBCPP_TEMPLATE_VIS hash<double>
1493    : public __scalar_hash<double>
1494{
1495    _LIBCPP_INLINE_VISIBILITY
1496    size_t operator()(double __v) const _NOEXCEPT
1497    {
1498        // -0.0 and 0.0 should return same hash
1499       if (__v == 0.0)
1500           return 0;
1501        return __scalar_hash<double>::operator()(__v);
1502    }
1503};
1504
1505template <>
1506struct _LIBCPP_TEMPLATE_VIS hash<long double>
1507    : public __scalar_hash<long double>
1508{
1509    _LIBCPP_INLINE_VISIBILITY
1510    size_t operator()(long double __v) const _NOEXCEPT
1511    {
1512        // -0.0 and 0.0 should return same hash
1513        if (__v == 0.0)
1514            return 0;
1515#if defined(__i386__)
1516        // Zero out padding bits
1517        union
1518        {
1519            long double __t;
1520            struct
1521            {
1522                size_t __a;
1523                size_t __b;
1524                size_t __c;
1525                size_t __d;
1526            } __s;
1527        } __u;
1528        __u.__s.__a = 0;
1529        __u.__s.__b = 0;
1530        __u.__s.__c = 0;
1531        __u.__s.__d = 0;
1532        __u.__t = __v;
1533        return __u.__s.__a ^ __u.__s.__b ^ __u.__s.__c ^ __u.__s.__d;
1534#elif defined(__x86_64__)
1535        // Zero out padding bits
1536        union
1537        {
1538            long double __t;
1539            struct
1540            {
1541                size_t __a;
1542                size_t __b;
1543            } __s;
1544        } __u;
1545        __u.__s.__a = 0;
1546        __u.__s.__b = 0;
1547        __u.__t = __v;
1548        return __u.__s.__a ^ __u.__s.__b;
1549#else
1550        return __scalar_hash<long double>::operator()(__v);
1551#endif
1552    }
1553};
1554
1555#if _LIBCPP_STD_VER > 11
1556
1557template <class _Tp, bool = is_enum<_Tp>::value>
1558struct _LIBCPP_TEMPLATE_VIS __enum_hash
1559    : public unary_function<_Tp, size_t>
1560{
1561    _LIBCPP_INLINE_VISIBILITY
1562    size_t operator()(_Tp __v) const _NOEXCEPT
1563    {
1564        typedef typename underlying_type<_Tp>::type type;
1565        return hash<type>{}(static_cast<type>(__v));
1566    }
1567};
1568template <class _Tp>
1569struct _LIBCPP_TEMPLATE_VIS __enum_hash<_Tp, false> {
1570    __enum_hash() = delete;
1571    __enum_hash(__enum_hash const&) = delete;
1572    __enum_hash& operator=(__enum_hash const&) = delete;
1573};
1574
1575template <class _Tp>
1576struct _LIBCPP_TEMPLATE_VIS hash : public __enum_hash<_Tp>
1577{
1578};
1579#endif
1580
1581#if _LIBCPP_STD_VER > 14
1582
1583template <>
1584struct _LIBCPP_TEMPLATE_VIS hash<nullptr_t>
1585  : public unary_function<nullptr_t, size_t>
1586{
1587  _LIBCPP_INLINE_VISIBILITY
1588  size_t operator()(nullptr_t) const _NOEXCEPT {
1589    return 662607004ull;
1590  }
1591};
1592#endif
1593
1594#ifndef _LIBCPP_CXX03_LANG
1595template <class _Key, class _Hash>
1596using __check_hash_requirements = integral_constant<bool,
1597    is_copy_constructible<_Hash>::value &&
1598    is_move_constructible<_Hash>::value &&
1599    __invokable_r<size_t, _Hash, _Key const&>::value
1600>;
1601
1602template <class _Key, class _Hash = std::hash<_Key> >
1603using __has_enabled_hash = integral_constant<bool,
1604    __check_hash_requirements<_Key, _Hash>::value &&
1605    is_default_constructible<_Hash>::value
1606>;
1607
1608#if _LIBCPP_STD_VER > 14
1609template <class _Type, class>
1610using __enable_hash_helper_imp = _Type;
1611
1612template <class _Type, class ..._Keys>
1613using __enable_hash_helper = __enable_hash_helper_imp<_Type,
1614  typename enable_if<__all<__has_enabled_hash<_Keys>::value...>::value>::type
1615>;
1616#else
1617template <class _Type, class ...>
1618using __enable_hash_helper = _Type;
1619#endif
1620
1621#endif // !_LIBCPP_CXX03_LANG
1622
1623_LIBCPP_END_NAMESPACE_STD
1624
1625#endif  // _LIBCPP_UTILITY
1626