1// -*- C++ -*-
2//===-------------------------- utility -----------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP_UTILITY
11#define _LIBCPP_UTILITY
12
13/*
14    utility synopsis
15
16#include <initializer_list>
17
18namespace std
19{
20
21template <class T>
22    void
23    swap(T& a, T& b);
24
25namespace rel_ops
26{
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    template<class T> bool operator>=(const T&, const T&);
31}
32
33template<class T>
34void
35swap(T& a, T& b) noexcept(is_nothrow_move_constructible<T>::value &&
36                          is_nothrow_move_assignable<T>::value);
37
38template <class T, size_t N>
39void
40swap(T (&a)[N], T (&b)[N]) noexcept(noexcept(swap(*a, *b)));
41
42template <class T> T&& forward(typename remove_reference<T>::type& t) noexcept;  // constexpr in C++14
43template <class T> T&& forward(typename remove_reference<T>::type&& t) noexcept; // constexpr in C++14
44
45template <class T> typename remove_reference<T>::type&& move(T&&) noexcept;      // constexpr in C++14
46
47template <class T>
48    typename conditional
49    <
50        !is_nothrow_move_constructible<T>::value && is_copy_constructible<T>::value,
51        const T&,
52        T&&
53    >::type
54    move_if_noexcept(T& x) noexcept; // constexpr in C++14
55
56template <class T> constexpr add_const_t<T>& as_const(T& t) noexcept;      // C++17
57template <class T>                      void as_const(const T&&) = delete; // C++17
58
59template <class T> typename add_rvalue_reference<T>::type declval() noexcept;
60
61template <class T1, class T2>
62struct pair
63{
64    typedef T1 first_type;
65    typedef T2 second_type;
66
67    T1 first;
68    T2 second;
69
70    pair(const pair&) = default;
71    pair(pair&&) = default;
72    explicit(see-below) constexpr pair();
73    explicit(see-below) pair(const T1& x, const T2& y);                          // constexpr in C++14
74    template <class U, class V> explicit(see-below) pair(U&& x, V&& y);          // constexpr in C++14
75    template <class U, class V> explicit(see-below) pair(const pair<U, V>& p);   // constexpr in C++14
76    template <class U, class V> explicit(see-below) pair(pair<U, V>&& p);        // constexpr in C++14
77    template <class... Args1, class... Args2>
78        pair(piecewise_construct_t, tuple<Args1...> first_args,
79             tuple<Args2...> second_args);                                       // constexpr in C++20
80
81    template <class U, class V> pair& operator=(const pair<U, V>& p);            // constexpr in C++20
82    pair& operator=(pair&& p) noexcept(is_nothrow_move_assignable<T1>::value &&
83                                       is_nothrow_move_assignable<T2>::value);   // constexpr in C++20
84    template <class U, class V> pair& operator=(pair<U, V>&& p);                 // constexpr in C++20
85
86    void swap(pair& p) noexcept(is_nothrow_swappable_v<T1> &&
87                                is_nothrow_swappable_v<T2>);                     // constexpr in C++20
88};
89
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
95template <class T1, class T2> bool operator<=(const pair<T1,T2>&, const pair<T1,T2>&); // constexpr in C++14
96
97template <class T1, class T2> pair<V1, V2> make_pair(T1&&, T2&&);                // constexpr in C++14
98template <class T1, class T2>
99void
100swap(pair<T1, T2>& x, pair<T1, T2>& y) noexcept(noexcept(x.swap(y)));            // constexpr in C++20
101
102struct piecewise_construct_t { explicit piecewise_construct_t() = default; };
103inline constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
104
105template <class T> struct tuple_size;
106template <size_t I, class T> struct tuple_element;
107
108template <class T1, class T2> struct tuple_size<pair<T1, T2> >;
109template <class T1, class T2> struct tuple_element<0, pair<T1, T2> >;
110template <class T1, class T2> struct tuple_element<1, pair<T1, T2> >;
111
112template<size_t I, class T1, class T2>
113    typename tuple_element<I, pair<T1, T2> >::type&
114    get(pair<T1, T2>&) noexcept; // constexpr in C++14
115
116template<size_t I, class T1, class T2>
117    const typename tuple_element<I, pair<T1, T2> >::type&
118    get(const pair<T1, T2>&) noexcept; // constexpr in C++14
119
120template<size_t I, class T1, class T2>
121    typename tuple_element<I, pair<T1, T2> >::type&&
122    get(pair<T1, T2>&&) noexcept; // constexpr in C++14
123
124template<size_t I, class T1, class T2>
125    const typename tuple_element<I, pair<T1, T2> >::type&&
126    get(const pair<T1, T2>&&) noexcept; // constexpr in C++14
127
128template<class T1, class T2>
129    constexpr T1& get(pair<T1, T2>&) noexcept; // C++14
130
131template<class T1, class T2>
132    constexpr const T1& get(const pair<T1, T2>&) noexcept; // C++14
133
134template<class T1, class T2>
135    constexpr T1&& get(pair<T1, T2>&&) noexcept; // C++14
136
137template<class T1, class T2>
138    constexpr const T1&& get(const pair<T1, T2>&&) noexcept; // C++14
139
140template<class T1, class T2>
141    constexpr T1& get(pair<T2, T1>&) noexcept; // C++14
142
143template<class T1, class T2>
144    constexpr const T1& get(const pair<T2, T1>&) noexcept; // C++14
145
146template<class T1, class T2>
147    constexpr T1&& get(pair<T2, T1>&&) noexcept; // C++14
148
149template<class T1, class T2>
150    constexpr const T1&& get(const pair<T2, T1>&&) noexcept; // C++14
151
152// C++14
153
154template<class T, T... I>
155struct integer_sequence
156{
157    typedef T value_type;
158
159    static constexpr size_t size() noexcept;
160};
161
162template<size_t... I>
163  using index_sequence = integer_sequence<size_t, I...>;
164
165template<class T, T N>
166  using make_integer_sequence = integer_sequence<T, 0, 1, ..., N-1>;
167template<size_t N>
168  using make_index_sequence = make_integer_sequence<size_t, N>;
169
170template<class... T>
171  using index_sequence_for = make_index_sequence<sizeof...(T)>;
172
173template<class T, class U=T>
174    T exchange(T& obj, U&& new_value);
175
176// 20.2.7, in-place construction // C++17
177struct in_place_t {
178  explicit in_place_t() = default;
179};
180inline constexpr in_place_t in_place{};
181template <class T>
182  struct in_place_type_t {
183    explicit in_place_type_t() = default;
184  };
185template <class T>
186  inline constexpr in_place_type_t<T> in_place_type{};
187template <size_t I>
188  struct in_place_index_t {
189    explicit in_place_index_t() = default;
190  };
191template <size_t I>
192  inline constexpr in_place_index_t<I> in_place_index{};
193
194// [utility.underlying], to_underlying
195template <class T>
196    constexpr underlying_type_t<T> to_underlying( T value ) noexcept; // C++2b
197
198}  // std
199
200*/
201
202#include <__config>
203#include <__tuple>
204#include <compare>
205#include <type_traits>
206#include <initializer_list>
207#include <cstddef>
208#include <cstring>
209#include <cstdint>
210#include <version>
211#include <__debug>
212
213#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
214#pragma GCC system_header
215#endif
216
217_LIBCPP_BEGIN_NAMESPACE_STD
218
219namespace rel_ops
220{
221
222template<class _Tp>
223inline _LIBCPP_INLINE_VISIBILITY
224bool
225operator!=(const _Tp& __x, const _Tp& __y)
226{
227    return !(__x == __y);
228}
229
230template<class _Tp>
231inline _LIBCPP_INLINE_VISIBILITY
232bool
233operator> (const _Tp& __x, const _Tp& __y)
234{
235    return __y < __x;
236}
237
238template<class _Tp>
239inline _LIBCPP_INLINE_VISIBILITY
240bool
241operator<=(const _Tp& __x, const _Tp& __y)
242{
243    return !(__y < __x);
244}
245
246template<class _Tp>
247inline _LIBCPP_INLINE_VISIBILITY
248bool
249operator>=(const _Tp& __x, const _Tp& __y)
250{
251    return !(__x < __y);
252}
253
254}  // rel_ops
255
256// swap_ranges is defined in <type_traits>`
257
258// swap is defined in <type_traits>
259
260// move_if_noexcept
261
262template <class _Tp>
263_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
264#ifndef _LIBCPP_CXX03_LANG
265typename conditional
266<
267    !is_nothrow_move_constructible<_Tp>::value && is_copy_constructible<_Tp>::value,
268    const _Tp&,
269    _Tp&&
270>::type
271#else  // _LIBCPP_CXX03_LANG
272const _Tp&
273#endif
274move_if_noexcept(_Tp& __x) _NOEXCEPT
275{
276    return _VSTD::move(__x);
277}
278
279#if _LIBCPP_STD_VER > 14
280template <class _Tp>
281_LIBCPP_NODISCARD_EXT constexpr add_const_t<_Tp>& as_const(_Tp& __t) noexcept { return __t; }
282
283template <class _Tp>
284void as_const(const _Tp&&) = delete;
285#endif
286
287struct _LIBCPP_TEMPLATE_VIS piecewise_construct_t { explicit piecewise_construct_t() = default; };
288#if defined(_LIBCPP_CXX03_LANG) || defined(_LIBCPP_BUILDING_LIBRARY)
289extern _LIBCPP_EXPORTED_FROM_ABI const piecewise_construct_t piecewise_construct;// = piecewise_construct_t();
290#else
291/* _LIBCPP_INLINE_VAR */ constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
292#endif
293
294#if defined(_LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR)
295template <class, class>
296struct __non_trivially_copyable_base {
297  _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
298  __non_trivially_copyable_base() _NOEXCEPT {}
299  _LIBCPP_CONSTEXPR_AFTER_CXX11 _LIBCPP_INLINE_VISIBILITY
300  __non_trivially_copyable_base(__non_trivially_copyable_base const&) _NOEXCEPT {}
301};
302#endif
303
304template <class _T1, class _T2>
305struct _LIBCPP_TEMPLATE_VIS pair
306#if defined(_LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR)
307: private __non_trivially_copyable_base<_T1, _T2>
308#endif
309{
310    typedef _T1 first_type;
311    typedef _T2 second_type;
312
313    _T1 first;
314    _T2 second;
315
316#if !defined(_LIBCPP_CXX03_LANG)
317    pair(pair const&) = default;
318    pair(pair&&) = default;
319#else
320  // Use the implicitly declared copy constructor in C++03
321#endif
322
323#ifdef _LIBCPP_CXX03_LANG
324    _LIBCPP_INLINE_VISIBILITY
325    pair() : first(), second() {}
326
327    _LIBCPP_INLINE_VISIBILITY
328    pair(_T1 const& __t1, _T2 const& __t2) : first(__t1), second(__t2) {}
329
330    template <class _U1, class _U2>
331    _LIBCPP_INLINE_VISIBILITY
332    pair(const pair<_U1, _U2>& __p) : first(__p.first), second(__p.second) {}
333
334    _LIBCPP_INLINE_VISIBILITY
335    pair& operator=(pair const& __p) {
336        first = __p.first;
337        second = __p.second;
338        return *this;
339    }
340#else
341    template <bool _Val>
342    using _EnableB _LIBCPP_NODEBUG_TYPE = typename enable_if<_Val, bool>::type;
343
344    struct _CheckArgs {
345      template <int&...>
346      static constexpr bool __enable_explicit_default() {
347          return is_default_constructible<_T1>::value
348              && is_default_constructible<_T2>::value
349              && !__enable_implicit_default<>();
350      }
351
352      template <int&...>
353      static constexpr bool __enable_implicit_default() {
354          return __is_implicitly_default_constructible<_T1>::value
355              && __is_implicitly_default_constructible<_T2>::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 _LIBCPP_NODEBUG_TYPE = 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 _LIBCPP_NODEBUG_TYPE = 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>::__enable_explicit_default()
407    > = false>
408    explicit _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
409    pair() _NOEXCEPT_(is_nothrow_default_constructible<first_type>::value &&
410                      is_nothrow_default_constructible<second_type>::value)
411        : first(), second() {}
412
413    template<bool _Dummy = true, _EnableB<
414            _CheckArgsDep<_Dummy>::__enable_implicit_default()
415    > = false>
416    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
417    pair() _NOEXCEPT_(is_nothrow_default_constructible<first_type>::value &&
418                      is_nothrow_default_constructible<second_type>::value)
419        : first(), second() {}
420
421    template <bool _Dummy = true, _EnableB<
422             _CheckArgsDep<_Dummy>::template __enable_explicit<_T1 const&, _T2 const&>()
423    > = false>
424    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
425    explicit pair(_T1 const& __t1, _T2 const& __t2)
426        _NOEXCEPT_(is_nothrow_copy_constructible<first_type>::value &&
427                   is_nothrow_copy_constructible<second_type>::value)
428        : first(__t1), second(__t2) {}
429
430    template<bool _Dummy = true, _EnableB<
431            _CheckArgsDep<_Dummy>::template __enable_implicit<_T1 const&, _T2 const&>()
432    > = false>
433    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
434    pair(_T1 const& __t1, _T2 const& __t2)
435        _NOEXCEPT_(is_nothrow_copy_constructible<first_type>::value &&
436                   is_nothrow_copy_constructible<second_type>::value)
437        : first(__t1), second(__t2) {}
438
439    template<class _U1, class _U2, _EnableB<
440             _CheckArgs::template __enable_explicit<_U1, _U2>()
441    > = false>
442    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
443    explicit pair(_U1&& __u1, _U2&& __u2)
444        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1>::value &&
445                    is_nothrow_constructible<second_type, _U2>::value))
446        : first(_VSTD::forward<_U1>(__u1)), second(_VSTD::forward<_U2>(__u2)) {}
447
448    template<class _U1, class _U2, _EnableB<
449            _CheckArgs::template __enable_implicit<_U1, _U2>()
450    > = false>
451    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
452    pair(_U1&& __u1, _U2&& __u2)
453        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1>::value &&
454                    is_nothrow_constructible<second_type, _U2>::value))
455        : first(_VSTD::forward<_U1>(__u1)), second(_VSTD::forward<_U2>(__u2)) {}
456
457    template<class _U1, class _U2, _EnableB<
458            _CheckArgs::template __enable_explicit<_U1 const&, _U2 const&>()
459    > = false>
460    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
461    explicit pair(pair<_U1, _U2> const& __p)
462        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1 const&>::value &&
463                    is_nothrow_constructible<second_type, _U2 const&>::value))
464        : first(__p.first), second(__p.second) {}
465
466    template<class _U1, class _U2, _EnableB<
467            _CheckArgs::template __enable_implicit<_U1 const&, _U2 const&>()
468    > = false>
469    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
470    pair(pair<_U1, _U2> const& __p)
471        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1 const&>::value &&
472                    is_nothrow_constructible<second_type, _U2 const&>::value))
473        : first(__p.first), second(__p.second) {}
474
475    template<class _U1, class _U2, _EnableB<
476            _CheckArgs::template __enable_explicit<_U1, _U2>()
477    > = false>
478    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
479    explicit pair(pair<_U1, _U2>&&__p)
480        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1&&>::value &&
481                    is_nothrow_constructible<second_type, _U2&&>::value))
482        : first(_VSTD::forward<_U1>(__p.first)), second(_VSTD::forward<_U2>(__p.second)) {}
483
484    template<class _U1, class _U2, _EnableB<
485            _CheckArgs::template __enable_implicit<_U1, _U2>()
486    > = false>
487    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
488    pair(pair<_U1, _U2>&& __p)
489        _NOEXCEPT_((is_nothrow_constructible<first_type, _U1&&>::value &&
490                    is_nothrow_constructible<second_type, _U2&&>::value))
491        : first(_VSTD::forward<_U1>(__p.first)), second(_VSTD::forward<_U2>(__p.second)) {}
492
493    template<class _Tuple, _EnableB<
494            _CheckTLC<_Tuple>::template __enable_explicit<_Tuple>()
495    > = false>
496    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
497    explicit pair(_Tuple&& __p)
498        : first(_VSTD::get<0>(_VSTD::forward<_Tuple>(__p))),
499          second(_VSTD::get<1>(_VSTD::forward<_Tuple>(__p))) {}
500
501    template<class _Tuple, _EnableB<
502            _CheckTLC<_Tuple>::template __enable_implicit<_Tuple>()
503    > = false>
504    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
505    pair(_Tuple&& __p)
506        : first(_VSTD::get<0>(_VSTD::forward<_Tuple>(__p))),
507          second(_VSTD::get<1>(_VSTD::forward<_Tuple>(__p))) {}
508
509    template <class... _Args1, class... _Args2>
510    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
511    pair(piecewise_construct_t __pc,
512         tuple<_Args1...> __first_args, tuple<_Args2...> __second_args)
513        _NOEXCEPT_((is_nothrow_constructible<first_type, _Args1...>::value &&
514                    is_nothrow_constructible<second_type, _Args2...>::value))
515        : pair(__pc, __first_args, __second_args,
516                typename __make_tuple_indices<sizeof...(_Args1)>::type(),
517                typename __make_tuple_indices<sizeof...(_Args2) >::type()) {}
518
519    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
520    pair& operator=(typename conditional<
521                        is_copy_assignable<first_type>::value &&
522                        is_copy_assignable<second_type>::value,
523                    pair, __nat>::type const& __p)
524        _NOEXCEPT_(is_nothrow_copy_assignable<first_type>::value &&
525                   is_nothrow_copy_assignable<second_type>::value)
526    {
527        first = __p.first;
528        second = __p.second;
529        return *this;
530    }
531
532    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
533    pair& operator=(typename conditional<
534                        is_move_assignable<first_type>::value &&
535                        is_move_assignable<second_type>::value,
536                    pair, __nat>::type&& __p)
537        _NOEXCEPT_(is_nothrow_move_assignable<first_type>::value &&
538                   is_nothrow_move_assignable<second_type>::value)
539    {
540        first = _VSTD::forward<first_type>(__p.first);
541        second = _VSTD::forward<second_type>(__p.second);
542        return *this;
543    }
544
545    template <class _Tuple, _EnableB<
546            _CheckTLC<_Tuple>::template __enable_assign<_Tuple>()
547     > = false>
548    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
549    pair& operator=(_Tuple&& __p) {
550        first = _VSTD::get<0>(_VSTD::forward<_Tuple>(__p));
551        second = _VSTD::get<1>(_VSTD::forward<_Tuple>(__p));
552        return *this;
553    }
554#endif
555
556    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
557    void
558    swap(pair& __p) _NOEXCEPT_(__is_nothrow_swappable<first_type>::value &&
559                               __is_nothrow_swappable<second_type>::value)
560    {
561        using _VSTD::swap;
562        swap(first,  __p.first);
563        swap(second, __p.second);
564    }
565private:
566
567#ifndef _LIBCPP_CXX03_LANG
568    template <class... _Args1, class... _Args2, size_t... _I1, size_t... _I2>
569    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
570    pair(piecewise_construct_t,
571         tuple<_Args1...>& __first_args, tuple<_Args2...>& __second_args,
572         __tuple_indices<_I1...>, __tuple_indices<_I2...>);
573#endif
574};
575
576#ifndef _LIBCPP_HAS_NO_DEDUCTION_GUIDES
577template<class _T1, class _T2>
578pair(_T1, _T2) -> pair<_T1, _T2>;
579#endif // _LIBCPP_HAS_NO_DEDUCTION_GUIDES
580
581template <class _T1, class _T2>
582inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
583bool
584operator==(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
585{
586    return __x.first == __y.first && __x.second == __y.second;
587}
588
589template <class _T1, class _T2>
590inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
591bool
592operator!=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
593{
594    return !(__x == __y);
595}
596
597template <class _T1, class _T2>
598inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
599bool
600operator< (const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
601{
602    return __x.first < __y.first || (!(__y.first < __x.first) && __x.second < __y.second);
603}
604
605template <class _T1, class _T2>
606inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
607bool
608operator> (const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
609{
610    return __y < __x;
611}
612
613template <class _T1, class _T2>
614inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
615bool
616operator>=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
617{
618    return !(__x < __y);
619}
620
621template <class _T1, class _T2>
622inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
623bool
624operator<=(const pair<_T1,_T2>& __x, const pair<_T1,_T2>& __y)
625{
626    return !(__y < __x);
627}
628
629template <class _T1, class _T2>
630inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
631typename enable_if
632<
633    __is_swappable<_T1>::value &&
634    __is_swappable<_T2>::value,
635    void
636>::type
637swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y)
638                     _NOEXCEPT_((__is_nothrow_swappable<_T1>::value &&
639                                 __is_nothrow_swappable<_T2>::value))
640{
641    __x.swap(__y);
642}
643
644template <class _Tp>
645struct __unwrap_reference { typedef _LIBCPP_NODEBUG_TYPE _Tp type; };
646
647template <class _Tp>
648struct __unwrap_reference<reference_wrapper<_Tp> > { typedef _LIBCPP_NODEBUG_TYPE _Tp& type; };
649
650#if _LIBCPP_STD_VER > 17
651template <class _Tp>
652struct unwrap_reference : __unwrap_reference<_Tp> { };
653
654template <class _Tp>
655struct unwrap_ref_decay : unwrap_reference<typename decay<_Tp>::type> { };
656#endif // > C++17
657
658template <class _Tp>
659struct __unwrap_ref_decay
660#if _LIBCPP_STD_VER > 17
661    : unwrap_ref_decay<_Tp>
662#else
663    : __unwrap_reference<typename decay<_Tp>::type>
664#endif
665{ };
666
667#ifndef _LIBCPP_CXX03_LANG
668
669template <class _T1, class _T2>
670inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
671pair<typename __unwrap_ref_decay<_T1>::type, typename __unwrap_ref_decay<_T2>::type>
672make_pair(_T1&& __t1, _T2&& __t2)
673{
674    return pair<typename __unwrap_ref_decay<_T1>::type, typename __unwrap_ref_decay<_T2>::type>
675               (_VSTD::forward<_T1>(__t1), _VSTD::forward<_T2>(__t2));
676}
677
678#else  // _LIBCPP_CXX03_LANG
679
680template <class _T1, class _T2>
681inline _LIBCPP_INLINE_VISIBILITY
682pair<_T1,_T2>
683make_pair(_T1 __x, _T2 __y)
684{
685    return pair<_T1, _T2>(__x, __y);
686}
687
688#endif  // _LIBCPP_CXX03_LANG
689
690template <class _T1, class _T2>
691  struct _LIBCPP_TEMPLATE_VIS tuple_size<pair<_T1, _T2> >
692    : public integral_constant<size_t, 2> {};
693
694template <size_t _Ip, class _T1, class _T2>
695struct _LIBCPP_TEMPLATE_VIS tuple_element<_Ip, pair<_T1, _T2> >
696{
697    static_assert(_Ip < 2, "Index out of bounds in std::tuple_element<std::pair<T1, T2>>");
698};
699
700template <class _T1, class _T2>
701struct _LIBCPP_TEMPLATE_VIS tuple_element<0, pair<_T1, _T2> >
702{
703    typedef _LIBCPP_NODEBUG_TYPE _T1 type;
704};
705
706template <class _T1, class _T2>
707struct _LIBCPP_TEMPLATE_VIS tuple_element<1, pair<_T1, _T2> >
708{
709    typedef _LIBCPP_NODEBUG_TYPE _T2 type;
710};
711
712template <size_t _Ip> struct __get_pair;
713
714template <>
715struct __get_pair<0>
716{
717    template <class _T1, class _T2>
718    static
719    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
720    _T1&
721    get(pair<_T1, _T2>& __p) _NOEXCEPT {return __p.first;}
722
723    template <class _T1, class _T2>
724    static
725    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
726    const _T1&
727    get(const pair<_T1, _T2>& __p) _NOEXCEPT {return __p.first;}
728
729#ifndef _LIBCPP_CXX03_LANG
730    template <class _T1, class _T2>
731    static
732    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
733    _T1&&
734    get(pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<_T1>(__p.first);}
735
736    template <class _T1, class _T2>
737    static
738    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
739    const _T1&&
740    get(const pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<const _T1>(__p.first);}
741#endif  // _LIBCPP_CXX03_LANG
742};
743
744template <>
745struct __get_pair<1>
746{
747    template <class _T1, class _T2>
748    static
749    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
750    _T2&
751    get(pair<_T1, _T2>& __p) _NOEXCEPT {return __p.second;}
752
753    template <class _T1, class _T2>
754    static
755    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
756    const _T2&
757    get(const pair<_T1, _T2>& __p) _NOEXCEPT {return __p.second;}
758
759#ifndef _LIBCPP_CXX03_LANG
760    template <class _T1, class _T2>
761    static
762    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
763    _T2&&
764    get(pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<_T2>(__p.second);}
765
766    template <class _T1, class _T2>
767    static
768    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
769    const _T2&&
770    get(const pair<_T1, _T2>&& __p) _NOEXCEPT {return _VSTD::forward<const _T2>(__p.second);}
771#endif  // _LIBCPP_CXX03_LANG
772};
773
774template <size_t _Ip, class _T1, class _T2>
775inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
776typename tuple_element<_Ip, pair<_T1, _T2> >::type&
777get(pair<_T1, _T2>& __p) _NOEXCEPT
778{
779    return __get_pair<_Ip>::get(__p);
780}
781
782template <size_t _Ip, class _T1, class _T2>
783inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
784const typename tuple_element<_Ip, pair<_T1, _T2> >::type&
785get(const pair<_T1, _T2>& __p) _NOEXCEPT
786{
787    return __get_pair<_Ip>::get(__p);
788}
789
790#ifndef _LIBCPP_CXX03_LANG
791template <size_t _Ip, class _T1, class _T2>
792inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
793typename tuple_element<_Ip, pair<_T1, _T2> >::type&&
794get(pair<_T1, _T2>&& __p) _NOEXCEPT
795{
796    return __get_pair<_Ip>::get(_VSTD::move(__p));
797}
798
799template <size_t _Ip, class _T1, class _T2>
800inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
801const typename tuple_element<_Ip, pair<_T1, _T2> >::type&&
802get(const pair<_T1, _T2>&& __p) _NOEXCEPT
803{
804    return __get_pair<_Ip>::get(_VSTD::move(__p));
805}
806#endif  // _LIBCPP_CXX03_LANG
807
808#if _LIBCPP_STD_VER > 11
809template <class _T1, class _T2>
810inline _LIBCPP_INLINE_VISIBILITY
811constexpr _T1 & get(pair<_T1, _T2>& __p) _NOEXCEPT
812{
813    return __get_pair<0>::get(__p);
814}
815
816template <class _T1, class _T2>
817inline _LIBCPP_INLINE_VISIBILITY
818constexpr _T1 const & get(pair<_T1, _T2> const& __p) _NOEXCEPT
819{
820    return __get_pair<0>::get(__p);
821}
822
823template <class _T1, class _T2>
824inline _LIBCPP_INLINE_VISIBILITY
825constexpr _T1 && get(pair<_T1, _T2>&& __p) _NOEXCEPT
826{
827    return __get_pair<0>::get(_VSTD::move(__p));
828}
829
830template <class _T1, class _T2>
831inline _LIBCPP_INLINE_VISIBILITY
832constexpr _T1 const && get(pair<_T1, _T2> const&& __p) _NOEXCEPT
833{
834    return __get_pair<0>::get(_VSTD::move(__p));
835}
836
837template <class _T1, class _T2>
838inline _LIBCPP_INLINE_VISIBILITY
839constexpr _T1 & get(pair<_T2, _T1>& __p) _NOEXCEPT
840{
841    return __get_pair<1>::get(__p);
842}
843
844template <class _T1, class _T2>
845inline _LIBCPP_INLINE_VISIBILITY
846constexpr _T1 const & get(pair<_T2, _T1> const& __p) _NOEXCEPT
847{
848    return __get_pair<1>::get(__p);
849}
850
851template <class _T1, class _T2>
852inline _LIBCPP_INLINE_VISIBILITY
853constexpr _T1 && get(pair<_T2, _T1>&& __p) _NOEXCEPT
854{
855    return __get_pair<1>::get(_VSTD::move(__p));
856}
857
858template <class _T1, class _T2>
859inline _LIBCPP_INLINE_VISIBILITY
860constexpr _T1 const && get(pair<_T2, _T1> const&& __p) _NOEXCEPT
861{
862    return __get_pair<1>::get(_VSTD::move(__p));
863}
864
865#endif
866
867#if _LIBCPP_STD_VER > 11
868
869template<class _Tp, _Tp... _Ip>
870struct _LIBCPP_TEMPLATE_VIS integer_sequence
871{
872    typedef _Tp value_type;
873    static_assert( is_integral<_Tp>::value,
874                  "std::integer_sequence can only be instantiated with an integral type" );
875    static
876    _LIBCPP_INLINE_VISIBILITY
877    constexpr
878    size_t
879    size() noexcept { return sizeof...(_Ip); }
880};
881
882template<size_t... _Ip>
883    using index_sequence = integer_sequence<size_t, _Ip...>;
884
885#if __has_builtin(__make_integer_seq) && !defined(_LIBCPP_TESTING_FALLBACK_MAKE_INTEGER_SEQUENCE)
886
887template <class _Tp, _Tp _Ep>
888using __make_integer_sequence _LIBCPP_NODEBUG_TYPE = __make_integer_seq<integer_sequence, _Tp, _Ep>;
889
890#else
891
892template<typename _Tp, _Tp _Np> using __make_integer_sequence_unchecked _LIBCPP_NODEBUG_TYPE  =
893  typename __detail::__make<_Np>::type::template __convert<integer_sequence, _Tp>;
894
895template <class _Tp, _Tp _Ep>
896struct __make_integer_sequence_checked
897{
898    static_assert(is_integral<_Tp>::value,
899                  "std::make_integer_sequence can only be instantiated with an integral type" );
900    static_assert(0 <= _Ep, "std::make_integer_sequence must have a non-negative sequence length");
901    // Workaround GCC bug by preventing bad installations when 0 <= _Ep
902    // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68929
903    typedef _LIBCPP_NODEBUG_TYPE  __make_integer_sequence_unchecked<_Tp, 0 <= _Ep ? _Ep : 0> type;
904};
905
906template <class _Tp, _Tp _Ep>
907using __make_integer_sequence _LIBCPP_NODEBUG_TYPE = typename __make_integer_sequence_checked<_Tp, _Ep>::type;
908
909#endif
910
911template<class _Tp, _Tp _Np>
912    using make_integer_sequence = __make_integer_sequence<_Tp, _Np>;
913
914template<size_t _Np>
915    using make_index_sequence = make_integer_sequence<size_t, _Np>;
916
917template<class... _Tp>
918    using index_sequence_for = make_index_sequence<sizeof...(_Tp)>;
919
920#endif  // _LIBCPP_STD_VER > 11
921
922#if _LIBCPP_STD_VER > 11
923template<class _T1, class _T2 = _T1>
924inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
925_T1 exchange(_T1& __obj, _T2 && __new_value)
926{
927    _T1 __old_value = _VSTD::move(__obj);
928    __obj = _VSTD::forward<_T2>(__new_value);
929    return __old_value;
930}
931#endif  // _LIBCPP_STD_VER > 11
932
933#if _LIBCPP_STD_VER > 14
934
935struct _LIBCPP_TYPE_VIS in_place_t {
936    explicit in_place_t() = default;
937};
938_LIBCPP_INLINE_VAR constexpr in_place_t in_place{};
939
940template <class _Tp>
941struct _LIBCPP_TEMPLATE_VIS in_place_type_t {
942    explicit in_place_type_t() = default;
943};
944template <class _Tp>
945_LIBCPP_INLINE_VAR constexpr in_place_type_t<_Tp> in_place_type{};
946
947template <size_t _Idx>
948struct _LIBCPP_TEMPLATE_VIS in_place_index_t {
949    explicit in_place_index_t() = default;
950};
951template <size_t _Idx>
952_LIBCPP_INLINE_VAR constexpr in_place_index_t<_Idx> in_place_index{};
953
954template <class _Tp> struct __is_inplace_type_imp : false_type {};
955template <class _Tp> struct __is_inplace_type_imp<in_place_type_t<_Tp>> : true_type {};
956
957template <class _Tp>
958using __is_inplace_type = __is_inplace_type_imp<__uncvref_t<_Tp>>;
959
960template <class _Tp> struct __is_inplace_index_imp : false_type {};
961template <size_t _Idx> struct __is_inplace_index_imp<in_place_index_t<_Idx>> : true_type {};
962
963template <class _Tp>
964using __is_inplace_index = __is_inplace_index_imp<__uncvref_t<_Tp>>;
965
966#endif // _LIBCPP_STD_VER > 14
967
968template <class _Arg, class _Result>
969struct _LIBCPP_TEMPLATE_VIS unary_function
970{
971    typedef _Arg    argument_type;
972    typedef _Result result_type;
973};
974
975template <class _Size>
976inline _LIBCPP_INLINE_VISIBILITY
977_Size
978__loadword(const void* __p)
979{
980    _Size __r;
981    _VSTD::memcpy(&__r, __p, sizeof(__r));
982    return __r;
983}
984
985// We use murmur2 when size_t is 32 bits, and cityhash64 when size_t
986// is 64 bits.  This is because cityhash64 uses 64bit x 64bit
987// multiplication, which can be very slow on 32-bit systems.
988template <class _Size, size_t = sizeof(_Size)*__CHAR_BIT__>
989struct __murmur2_or_cityhash;
990
991template <class _Size>
992struct __murmur2_or_cityhash<_Size, 32>
993{
994    inline _Size operator()(const void* __key, _Size __len)
995         _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK;
996};
997
998// murmur2
999template <class _Size>
1000_Size
1001__murmur2_or_cityhash<_Size, 32>::operator()(const void* __key, _Size __len)
1002{
1003    const _Size __m = 0x5bd1e995;
1004    const _Size __r = 24;
1005    _Size __h = __len;
1006    const unsigned char* __data = static_cast<const unsigned char*>(__key);
1007    for (; __len >= 4; __data += 4, __len -= 4)
1008    {
1009        _Size __k = __loadword<_Size>(__data);
1010        __k *= __m;
1011        __k ^= __k >> __r;
1012        __k *= __m;
1013        __h *= __m;
1014        __h ^= __k;
1015    }
1016    switch (__len)
1017    {
1018    case 3:
1019        __h ^= __data[2] << 16;
1020        _LIBCPP_FALLTHROUGH();
1021    case 2:
1022        __h ^= __data[1] << 8;
1023        _LIBCPP_FALLTHROUGH();
1024    case 1:
1025        __h ^= __data[0];
1026        __h *= __m;
1027    }
1028    __h ^= __h >> 13;
1029    __h *= __m;
1030    __h ^= __h >> 15;
1031    return __h;
1032}
1033
1034template <class _Size>
1035struct __murmur2_or_cityhash<_Size, 64>
1036{
1037    inline _Size operator()(const void* __key, _Size __len)  _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK;
1038
1039 private:
1040  // Some primes between 2^63 and 2^64.
1041  static const _Size __k0 = 0xc3a5c85c97cb3127ULL;
1042  static const _Size __k1 = 0xb492b66fbe98f273ULL;
1043  static const _Size __k2 = 0x9ae16a3b2f90404fULL;
1044  static const _Size __k3 = 0xc949d7c7509e6557ULL;
1045
1046  static _Size __rotate(_Size __val, int __shift) {
1047    return __shift == 0 ? __val : ((__val >> __shift) | (__val << (64 - __shift)));
1048  }
1049
1050  static _Size __rotate_by_at_least_1(_Size __val, int __shift) {
1051    return (__val >> __shift) | (__val << (64 - __shift));
1052  }
1053
1054  static _Size __shift_mix(_Size __val) {
1055    return __val ^ (__val >> 47);
1056  }
1057
1058  static _Size __hash_len_16(_Size __u, _Size __v)
1059     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1060  {
1061    const _Size __mul = 0x9ddfea08eb382d69ULL;
1062    _Size __a = (__u ^ __v) * __mul;
1063    __a ^= (__a >> 47);
1064    _Size __b = (__v ^ __a) * __mul;
1065    __b ^= (__b >> 47);
1066    __b *= __mul;
1067    return __b;
1068  }
1069
1070  static _Size __hash_len_0_to_16(const char* __s, _Size __len)
1071     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1072  {
1073    if (__len > 8) {
1074      const _Size __a = __loadword<_Size>(__s);
1075      const _Size __b = __loadword<_Size>(__s + __len - 8);
1076      return __hash_len_16(__a, __rotate_by_at_least_1(__b + __len, __len)) ^ __b;
1077    }
1078    if (__len >= 4) {
1079      const uint32_t __a = __loadword<uint32_t>(__s);
1080      const uint32_t __b = __loadword<uint32_t>(__s + __len - 4);
1081      return __hash_len_16(__len + (__a << 3), __b);
1082    }
1083    if (__len > 0) {
1084      const unsigned char __a = __s[0];
1085      const unsigned char __b = __s[__len >> 1];
1086      const unsigned char __c = __s[__len - 1];
1087      const uint32_t __y = static_cast<uint32_t>(__a) +
1088                           (static_cast<uint32_t>(__b) << 8);
1089      const uint32_t __z = __len + (static_cast<uint32_t>(__c) << 2);
1090      return __shift_mix(__y * __k2 ^ __z * __k3) * __k2;
1091    }
1092    return __k2;
1093  }
1094
1095  static _Size __hash_len_17_to_32(const char *__s, _Size __len)
1096     _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1097  {
1098    const _Size __a = __loadword<_Size>(__s) * __k1;
1099    const _Size __b = __loadword<_Size>(__s + 8);
1100    const _Size __c = __loadword<_Size>(__s + __len - 8) * __k2;
1101    const _Size __d = __loadword<_Size>(__s + __len - 16) * __k0;
1102    return __hash_len_16(__rotate(__a - __b, 43) + __rotate(__c, 30) + __d,
1103                         __a + __rotate(__b ^ __k3, 20) - __c + __len);
1104  }
1105
1106  // Return a 16-byte hash for 48 bytes.  Quick and dirty.
1107  // Callers do best to use "random-looking" values for a and b.
1108  static pair<_Size, _Size> __weak_hash_len_32_with_seeds(
1109      _Size __w, _Size __x, _Size __y, _Size __z, _Size __a, _Size __b)
1110        _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1111  {
1112    __a += __w;
1113    __b = __rotate(__b + __a + __z, 21);
1114    const _Size __c = __a;
1115    __a += __x;
1116    __a += __y;
1117    __b += __rotate(__a, 44);
1118    return pair<_Size, _Size>(__a + __z, __b + __c);
1119  }
1120
1121  // Return a 16-byte hash for s[0] ... s[31], a, and b.  Quick and dirty.
1122  static pair<_Size, _Size> __weak_hash_len_32_with_seeds(
1123      const char* __s, _Size __a, _Size __b)
1124    _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1125  {
1126    return __weak_hash_len_32_with_seeds(__loadword<_Size>(__s),
1127                                         __loadword<_Size>(__s + 8),
1128                                         __loadword<_Size>(__s + 16),
1129                                         __loadword<_Size>(__s + 24),
1130                                         __a,
1131                                         __b);
1132  }
1133
1134  // Return an 8-byte hash for 33 to 64 bytes.
1135  static _Size __hash_len_33_to_64(const char *__s, size_t __len)
1136    _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
1137  {
1138    _Size __z = __loadword<_Size>(__s + 24);
1139    _Size __a = __loadword<_Size>(__s) +
1140                (__len + __loadword<_Size>(__s + __len - 16)) * __k0;
1141    _Size __b = __rotate(__a + __z, 52);
1142    _Size __c = __rotate(__a, 37);
1143    __a += __loadword<_Size>(__s + 8);
1144    __c += __rotate(__a, 7);
1145    __a += __loadword<_Size>(__s + 16);
1146    _Size __vf = __a + __z;
1147    _Size __vs = __b + __rotate(__a, 31) + __c;
1148    __a = __loadword<_Size>(__s + 16) + __loadword<_Size>(__s + __len - 32);
1149    __z += __loadword<_Size>(__s + __len - 8);
1150    __b = __rotate(__a + __z, 52);
1151    __c = __rotate(__a, 37);
1152    __a += __loadword<_Size>(__s + __len - 24);
1153    __c += __rotate(__a, 7);
1154    __a += __loadword<_Size>(__s + __len - 16);
1155    _Size __wf = __a + __z;
1156    _Size __ws = __b + __rotate(__a, 31) + __c;
1157    _Size __r = __shift_mix((__vf + __ws) * __k2 + (__wf + __vs) * __k0);
1158    return __shift_mix(__r * __k0 + __vs) * __k2;
1159  }
1160};
1161
1162// cityhash64
1163template <class _Size>
1164_Size
1165__murmur2_or_cityhash<_Size, 64>::operator()(const void* __key, _Size __len)
1166{
1167  const char* __s = static_cast<const char*>(__key);
1168  if (__len <= 32) {
1169    if (__len <= 16) {
1170      return __hash_len_0_to_16(__s, __len);
1171    } else {
1172      return __hash_len_17_to_32(__s, __len);
1173    }
1174  } else if (__len <= 64) {
1175    return __hash_len_33_to_64(__s, __len);
1176  }
1177
1178  // For strings over 64 bytes we hash the end first, and then as we
1179  // loop we keep 56 bytes of state: v, w, x, y, and z.
1180  _Size __x = __loadword<_Size>(__s + __len - 40);
1181  _Size __y = __loadword<_Size>(__s + __len - 16) +
1182              __loadword<_Size>(__s + __len - 56);
1183  _Size __z = __hash_len_16(__loadword<_Size>(__s + __len - 48) + __len,
1184                          __loadword<_Size>(__s + __len - 24));
1185  pair<_Size, _Size> __v = __weak_hash_len_32_with_seeds(__s + __len - 64, __len, __z);
1186  pair<_Size, _Size> __w = __weak_hash_len_32_with_seeds(__s + __len - 32, __y + __k1, __x);
1187  __x = __x * __k1 + __loadword<_Size>(__s);
1188
1189  // Decrease len to the nearest multiple of 64, and operate on 64-byte chunks.
1190  __len = (__len - 1) & ~static_cast<_Size>(63);
1191  do {
1192    __x = __rotate(__x + __y + __v.first + __loadword<_Size>(__s + 8), 37) * __k1;
1193    __y = __rotate(__y + __v.second + __loadword<_Size>(__s + 48), 42) * __k1;
1194    __x ^= __w.second;
1195    __y += __v.first + __loadword<_Size>(__s + 40);
1196    __z = __rotate(__z + __w.first, 33) * __k1;
1197    __v = __weak_hash_len_32_with_seeds(__s, __v.second * __k1, __x + __w.first);
1198    __w = __weak_hash_len_32_with_seeds(__s + 32, __z + __w.second,
1199                                        __y + __loadword<_Size>(__s + 16));
1200    _VSTD::swap(__z, __x);
1201    __s += 64;
1202    __len -= 64;
1203  } while (__len != 0);
1204  return __hash_len_16(
1205      __hash_len_16(__v.first, __w.first) + __shift_mix(__y) * __k1 + __z,
1206      __hash_len_16(__v.second, __w.second) + __x);
1207}
1208
1209template <class _Tp, size_t = sizeof(_Tp) / sizeof(size_t)>
1210struct __scalar_hash;
1211
1212template <class _Tp>
1213struct __scalar_hash<_Tp, 0>
1214    : public unary_function<_Tp, size_t>
1215{
1216    _LIBCPP_INLINE_VISIBILITY
1217    size_t operator()(_Tp __v) const _NOEXCEPT
1218    {
1219        union
1220        {
1221            _Tp    __t;
1222            size_t __a;
1223        } __u;
1224        __u.__a = 0;
1225        __u.__t = __v;
1226        return __u.__a;
1227    }
1228};
1229
1230template <class _Tp>
1231struct __scalar_hash<_Tp, 1>
1232    : public unary_function<_Tp, size_t>
1233{
1234    _LIBCPP_INLINE_VISIBILITY
1235    size_t operator()(_Tp __v) const _NOEXCEPT
1236    {
1237        union
1238        {
1239            _Tp    __t;
1240            size_t __a;
1241        } __u;
1242        __u.__t = __v;
1243        return __u.__a;
1244    }
1245};
1246
1247template <class _Tp>
1248struct __scalar_hash<_Tp, 2>
1249    : public unary_function<_Tp, size_t>
1250{
1251    _LIBCPP_INLINE_VISIBILITY
1252    size_t operator()(_Tp __v) const _NOEXCEPT
1253    {
1254        union
1255        {
1256            _Tp __t;
1257            struct
1258            {
1259                size_t __a;
1260                size_t __b;
1261            } __s;
1262        } __u;
1263        __u.__t = __v;
1264        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
1265    }
1266};
1267
1268template <class _Tp>
1269struct __scalar_hash<_Tp, 3>
1270    : public unary_function<_Tp, size_t>
1271{
1272    _LIBCPP_INLINE_VISIBILITY
1273    size_t operator()(_Tp __v) const _NOEXCEPT
1274    {
1275        union
1276        {
1277            _Tp __t;
1278            struct
1279            {
1280                size_t __a;
1281                size_t __b;
1282                size_t __c;
1283            } __s;
1284        } __u;
1285        __u.__t = __v;
1286        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
1287    }
1288};
1289
1290template <class _Tp>
1291struct __scalar_hash<_Tp, 4>
1292    : public unary_function<_Tp, size_t>
1293{
1294    _LIBCPP_INLINE_VISIBILITY
1295    size_t operator()(_Tp __v) const _NOEXCEPT
1296    {
1297        union
1298        {
1299            _Tp __t;
1300            struct
1301            {
1302                size_t __a;
1303                size_t __b;
1304                size_t __c;
1305                size_t __d;
1306            } __s;
1307        } __u;
1308        __u.__t = __v;
1309        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
1310    }
1311};
1312
1313struct _PairT {
1314  size_t first;
1315  size_t second;
1316};
1317
1318_LIBCPP_INLINE_VISIBILITY
1319inline size_t __hash_combine(size_t __lhs, size_t __rhs) _NOEXCEPT {
1320    typedef __scalar_hash<_PairT> _HashT;
1321    const _PairT __p = {__lhs, __rhs};
1322    return _HashT()(__p);
1323}
1324
1325template<class _Tp>
1326struct _LIBCPP_TEMPLATE_VIS hash<_Tp*>
1327    : public unary_function<_Tp*, size_t>
1328{
1329    _LIBCPP_INLINE_VISIBILITY
1330    size_t operator()(_Tp* __v) const _NOEXCEPT
1331    {
1332        union
1333        {
1334            _Tp* __t;
1335            size_t __a;
1336        } __u;
1337        __u.__t = __v;
1338        return __murmur2_or_cityhash<size_t>()(&__u, sizeof(__u));
1339    }
1340};
1341
1342
1343template <>
1344struct _LIBCPP_TEMPLATE_VIS hash<bool>
1345    : public unary_function<bool, size_t>
1346{
1347    _LIBCPP_INLINE_VISIBILITY
1348    size_t operator()(bool __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1349};
1350
1351template <>
1352struct _LIBCPP_TEMPLATE_VIS hash<char>
1353    : public unary_function<char, size_t>
1354{
1355    _LIBCPP_INLINE_VISIBILITY
1356    size_t operator()(char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1357};
1358
1359template <>
1360struct _LIBCPP_TEMPLATE_VIS hash<signed char>
1361    : public unary_function<signed char, size_t>
1362{
1363    _LIBCPP_INLINE_VISIBILITY
1364    size_t operator()(signed char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1365};
1366
1367template <>
1368struct _LIBCPP_TEMPLATE_VIS hash<unsigned char>
1369    : public unary_function<unsigned char, size_t>
1370{
1371    _LIBCPP_INLINE_VISIBILITY
1372    size_t operator()(unsigned char __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1373};
1374
1375#ifndef _LIBCPP_NO_HAS_CHAR8_T
1376template <>
1377struct _LIBCPP_TEMPLATE_VIS hash<char8_t>
1378    : public unary_function<char8_t, size_t>
1379{
1380    _LIBCPP_INLINE_VISIBILITY
1381    size_t operator()(char8_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1382};
1383#endif // !_LIBCPP_NO_HAS_CHAR8_T
1384
1385#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
1386
1387template <>
1388struct _LIBCPP_TEMPLATE_VIS hash<char16_t>
1389    : public unary_function<char16_t, size_t>
1390{
1391    _LIBCPP_INLINE_VISIBILITY
1392    size_t operator()(char16_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1393};
1394
1395template <>
1396struct _LIBCPP_TEMPLATE_VIS hash<char32_t>
1397    : public unary_function<char32_t, size_t>
1398{
1399    _LIBCPP_INLINE_VISIBILITY
1400    size_t operator()(char32_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1401};
1402
1403#endif  // _LIBCPP_HAS_NO_UNICODE_CHARS
1404
1405template <>
1406struct _LIBCPP_TEMPLATE_VIS hash<wchar_t>
1407    : public unary_function<wchar_t, size_t>
1408{
1409    _LIBCPP_INLINE_VISIBILITY
1410    size_t operator()(wchar_t __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1411};
1412
1413template <>
1414struct _LIBCPP_TEMPLATE_VIS hash<short>
1415    : public unary_function<short, size_t>
1416{
1417    _LIBCPP_INLINE_VISIBILITY
1418    size_t operator()(short __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1419};
1420
1421template <>
1422struct _LIBCPP_TEMPLATE_VIS hash<unsigned short>
1423    : public unary_function<unsigned short, size_t>
1424{
1425    _LIBCPP_INLINE_VISIBILITY
1426    size_t operator()(unsigned short __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1427};
1428
1429template <>
1430struct _LIBCPP_TEMPLATE_VIS hash<int>
1431    : public unary_function<int, size_t>
1432{
1433    _LIBCPP_INLINE_VISIBILITY
1434    size_t operator()(int __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1435};
1436
1437template <>
1438struct _LIBCPP_TEMPLATE_VIS hash<unsigned int>
1439    : public unary_function<unsigned int, size_t>
1440{
1441    _LIBCPP_INLINE_VISIBILITY
1442    size_t operator()(unsigned int __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1443};
1444
1445template <>
1446struct _LIBCPP_TEMPLATE_VIS hash<long>
1447    : public unary_function<long, size_t>
1448{
1449    _LIBCPP_INLINE_VISIBILITY
1450    size_t operator()(long __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1451};
1452
1453template <>
1454struct _LIBCPP_TEMPLATE_VIS hash<unsigned long>
1455    : public unary_function<unsigned long, size_t>
1456{
1457    _LIBCPP_INLINE_VISIBILITY
1458    size_t operator()(unsigned long __v) const _NOEXCEPT {return static_cast<size_t>(__v);}
1459};
1460
1461template <>
1462struct _LIBCPP_TEMPLATE_VIS hash<long long>
1463    : public __scalar_hash<long long>
1464{
1465};
1466
1467template <>
1468struct _LIBCPP_TEMPLATE_VIS hash<unsigned long long>
1469    : public __scalar_hash<unsigned long long>
1470{
1471};
1472
1473#ifndef _LIBCPP_HAS_NO_INT128
1474
1475template <>
1476struct _LIBCPP_TEMPLATE_VIS hash<__int128_t>
1477    : public __scalar_hash<__int128_t>
1478{
1479};
1480
1481template <>
1482struct _LIBCPP_TEMPLATE_VIS hash<__uint128_t>
1483    : public __scalar_hash<__uint128_t>
1484{
1485};
1486
1487#endif
1488
1489template <>
1490struct _LIBCPP_TEMPLATE_VIS hash<float>
1491    : public __scalar_hash<float>
1492{
1493    _LIBCPP_INLINE_VISIBILITY
1494    size_t operator()(float __v) const _NOEXCEPT
1495    {
1496        // -0.0 and 0.0 should return same hash
1497       if (__v == 0.0f)
1498           return 0;
1499        return __scalar_hash<float>::operator()(__v);
1500    }
1501};
1502
1503template <>
1504struct _LIBCPP_TEMPLATE_VIS hash<double>
1505    : public __scalar_hash<double>
1506{
1507    _LIBCPP_INLINE_VISIBILITY
1508    size_t operator()(double __v) const _NOEXCEPT
1509    {
1510        // -0.0 and 0.0 should return same hash
1511       if (__v == 0.0)
1512           return 0;
1513        return __scalar_hash<double>::operator()(__v);
1514    }
1515};
1516
1517template <>
1518struct _LIBCPP_TEMPLATE_VIS hash<long double>
1519    : public __scalar_hash<long double>
1520{
1521    _LIBCPP_INLINE_VISIBILITY
1522    size_t operator()(long double __v) const _NOEXCEPT
1523    {
1524        // -0.0 and 0.0 should return same hash
1525        if (__v == 0.0L)
1526            return 0;
1527#if defined(__i386__) || (defined(__x86_64__) && defined(__ILP32__))
1528        // Zero out padding bits
1529        union
1530        {
1531            long double __t;
1532            struct
1533            {
1534                size_t __a;
1535                size_t __b;
1536                size_t __c;
1537                size_t __d;
1538            } __s;
1539        } __u;
1540        __u.__s.__a = 0;
1541        __u.__s.__b = 0;
1542        __u.__s.__c = 0;
1543        __u.__s.__d = 0;
1544        __u.__t = __v;
1545        return __u.__s.__a ^ __u.__s.__b ^ __u.__s.__c ^ __u.__s.__d;
1546#elif defined(__x86_64__)
1547        // Zero out padding bits
1548        union
1549        {
1550            long double __t;
1551            struct
1552            {
1553                size_t __a;
1554                size_t __b;
1555            } __s;
1556        } __u;
1557        __u.__s.__a = 0;
1558        __u.__s.__b = 0;
1559        __u.__t = __v;
1560        return __u.__s.__a ^ __u.__s.__b;
1561#else
1562        return __scalar_hash<long double>::operator()(__v);
1563#endif
1564    }
1565};
1566
1567#if _LIBCPP_STD_VER > 11
1568
1569template <class _Tp, bool = is_enum<_Tp>::value>
1570struct _LIBCPP_TEMPLATE_VIS __enum_hash
1571    : public unary_function<_Tp, size_t>
1572{
1573    _LIBCPP_INLINE_VISIBILITY
1574    size_t operator()(_Tp __v) const _NOEXCEPT
1575    {
1576        typedef typename underlying_type<_Tp>::type type;
1577        return hash<type>{}(static_cast<type>(__v));
1578    }
1579};
1580template <class _Tp>
1581struct _LIBCPP_TEMPLATE_VIS __enum_hash<_Tp, false> {
1582    __enum_hash() = delete;
1583    __enum_hash(__enum_hash const&) = delete;
1584    __enum_hash& operator=(__enum_hash const&) = delete;
1585};
1586
1587template <class _Tp>
1588struct _LIBCPP_TEMPLATE_VIS hash : public __enum_hash<_Tp>
1589{
1590};
1591#endif
1592
1593#if _LIBCPP_STD_VER > 14
1594
1595template <>
1596struct _LIBCPP_TEMPLATE_VIS hash<nullptr_t>
1597  : public unary_function<nullptr_t, size_t>
1598{
1599  _LIBCPP_INLINE_VISIBILITY
1600  size_t operator()(nullptr_t) const _NOEXCEPT {
1601    return 662607004ull;
1602  }
1603};
1604#endif
1605
1606#ifndef _LIBCPP_CXX03_LANG
1607template <class _Key, class _Hash>
1608using __check_hash_requirements _LIBCPP_NODEBUG_TYPE  = integral_constant<bool,
1609    is_copy_constructible<_Hash>::value &&
1610    is_move_constructible<_Hash>::value &&
1611    __invokable_r<size_t, _Hash, _Key const&>::value
1612>;
1613
1614template <class _Key, class _Hash = hash<_Key> >
1615using __has_enabled_hash _LIBCPP_NODEBUG_TYPE = integral_constant<bool,
1616    __check_hash_requirements<_Key, _Hash>::value &&
1617    is_default_constructible<_Hash>::value
1618>;
1619
1620#if _LIBCPP_STD_VER > 14
1621template <class _Type, class>
1622using __enable_hash_helper_imp _LIBCPP_NODEBUG_TYPE  = _Type;
1623
1624template <class _Type, class ..._Keys>
1625using __enable_hash_helper _LIBCPP_NODEBUG_TYPE  = __enable_hash_helper_imp<_Type,
1626  typename enable_if<__all<__has_enabled_hash<_Keys>::value...>::value>::type
1627>;
1628#else
1629template <class _Type, class ...>
1630using __enable_hash_helper _LIBCPP_NODEBUG_TYPE = _Type;
1631#endif
1632
1633template <class _Tp>
1634_LIBCPP_INLINE_VISIBILITY constexpr typename underlying_type<_Tp>::type
1635__to_underlying(_Tp __val) noexcept {
1636  return static_cast<typename underlying_type<_Tp>::type>(__val);
1637}
1638#endif // !_LIBCPP_CXX03_LANG
1639
1640#if _LIBCPP_STD_VER > 20
1641template <class _Tp>
1642_LIBCPP_NODISCARD_EXT _LIBCPP_INLINE_VISIBILITY constexpr underlying_type_t<_Tp>
1643to_underlying(_Tp __val) noexcept {
1644  return _VSTD::__to_underlying(__val);
1645}
1646#endif
1647
1648_LIBCPP_END_NAMESPACE_STD
1649
1650#endif  // _LIBCPP_UTILITY
1651