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1// -*- C++ -*-
2//===--------------------------- tuple ------------------------------------===//
3//
4//                     The LLVM Compiler Infrastructure
5//
6// This file is distributed under the University of Illinois Open Source
7// License. See LICENSE.TXT for details.
8//
9//===----------------------------------------------------------------------===//
10
11#ifndef _LIBCPP_TUPLE
12#define _LIBCPP_TUPLE
13
14/*
15    tuple synopsis
16
17namespace std
18{
19
20template <class... T>
21class tuple {
22public:
23    constexpr tuple();
24    explicit tuple(const T&...);  // constexpr in C++14
25    template <class... U>
26        explicit tuple(U&&...);  // constexpr in C++14
27    tuple(const tuple&) = default;
28    tuple(tuple&&) = default;
29    template <class... U>
30        tuple(const tuple<U...>&);  // constexpr in C++14
31    template <class... U>
32        tuple(tuple<U...>&&);  // constexpr in C++14
33    template <class U1, class U2>
34        tuple(const pair<U1, U2>&); // iff sizeof...(T) == 2 // constexpr in C++14
35    template <class U1, class U2>
36        tuple(pair<U1, U2>&&); // iff sizeof...(T) == 2  // constexpr in C++14
37
38    // allocator-extended constructors
39    template <class Alloc>
40        tuple(allocator_arg_t, const Alloc& a);
41    template <class Alloc>
42        tuple(allocator_arg_t, const Alloc& a, const T&...);
43    template <class Alloc, class... U>
44        tuple(allocator_arg_t, const Alloc& a, U&&...);
45    template <class Alloc>
46        tuple(allocator_arg_t, const Alloc& a, const tuple&);
47    template <class Alloc>
48        tuple(allocator_arg_t, const Alloc& a, tuple&&);
49    template <class Alloc, class... U>
50        tuple(allocator_arg_t, const Alloc& a, const tuple<U...>&);
51    template <class Alloc, class... U>
52        tuple(allocator_arg_t, const Alloc& a, tuple<U...>&&);
53    template <class Alloc, class U1, class U2>
54        tuple(allocator_arg_t, const Alloc& a, const pair<U1, U2>&);
55    template <class Alloc, class U1, class U2>
56        tuple(allocator_arg_t, const Alloc& a, pair<U1, U2>&&);
57
58    tuple& operator=(const tuple&);
59    tuple&
60        operator=(tuple&&) noexcept(AND(is_nothrow_move_assignable<T>::value ...));
61    template <class... U>
62        tuple& operator=(const tuple<U...>&);
63    template <class... U>
64        tuple& operator=(tuple<U...>&&);
65    template <class U1, class U2>
66        tuple& operator=(const pair<U1, U2>&); // iff sizeof...(T) == 2
67    template <class U1, class U2>
68        tuple& operator=(pair<U1, U2>&&); // iff sizeof...(T) == 2
69
70    void swap(tuple&) noexcept(AND(swap(declval<T&>(), declval<T&>())...));
71};
72
73inline constexpr unspecified ignore;
74
75template <class... T> tuple<V...>  make_tuple(T&&...); // constexpr in C++14
76template <class... T> tuple<ATypes...> forward_as_tuple(T&&...) noexcept; // constexpr in C++14
77template <class... T> tuple<T&...> tie(T&...) noexcept; // constexpr in C++14
78template <class... Tuples> tuple<CTypes...> tuple_cat(Tuples&&... tpls); // constexpr in C++14
79
80// [tuple.apply], calling a function with a tuple of arguments:
81template <class F, class Tuple>
82  constexpr decltype(auto) apply(F&& f, Tuple&& t); // C++17
83template <class T, class Tuple>
84  constexpr T make_from_tuple(Tuple&& t); // C++17
85
86// 20.4.1.4, tuple helper classes:
87template <class T> struct tuple_size; // undefined
88template <class... T> struct tuple_size<tuple<T...>>;
89template <class T>
90 inline constexpr size_t tuple_size_v = tuple_size<T>::value; // C++17
91template <size_t I, class T> class tuple_element; // undefined
92template <size_t I, class... T> class tuple_element<I, tuple<T...>>;
93template <size_t I, class T>
94  using tuple_element_t = typename tuple_element <I, T>::type; // C++14
95
96// 20.4.1.5, element access:
97template <size_t I, class... T>
98    typename tuple_element<I, tuple<T...>>::type&
99    get(tuple<T...>&) noexcept; // constexpr in C++14
100template <size_t I, class... T>
101    const typename tuple_element<I, tuple<T...>>::type&
102    get(const tuple<T...>&) noexcept; // constexpr in C++14
103template <size_t I, class... T>
104    typename tuple_element<I, tuple<T...>>::type&&
105    get(tuple<T...>&&) noexcept; // constexpr in C++14
106template <size_t I, class... T>
107    const typename tuple_element<I, tuple<T...>>::type&&
108    get(const tuple<T...>&&) noexcept; // constexpr in C++14
109
110template <class T1, class... T>
111    constexpr T1& get(tuple<T...>&) noexcept;  // C++14
112template <class T1, class... T>
113    constexpr const T1& get(const tuple<T...>&) noexcept;   // C++14
114template <class T1, class... T>
115    constexpr T1&& get(tuple<T...>&&) noexcept;   // C++14
116template <class T1, class... T>
117    constexpr const T1&& get(const tuple<T...>&&) noexcept;   // C++14
118
119// 20.4.1.6, relational operators:
120template<class... T, class... U> bool operator==(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14
121template<class... T, class... U> bool operator<(const tuple<T...>&, const tuple<U...>&);  // constexpr in C++14
122template<class... T, class... U> bool operator!=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14
123template<class... T, class... U> bool operator>(const tuple<T...>&, const tuple<U...>&);  // constexpr in C++14
124template<class... T, class... U> bool operator<=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14
125template<class... T, class... U> bool operator>=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14
126
127template <class... Types, class Alloc>
128  struct uses_allocator<tuple<Types...>, Alloc>;
129
130template <class... Types>
131  void
132  swap(tuple<Types...>& x, tuple<Types...>& y) noexcept(noexcept(x.swap(y)));
133
134}  // std
135
136*/
137
138#include <__config>
139#include <__tuple>
140#include <cstddef>
141#include <type_traits>
142#include <__functional_base>
143#include <utility>
144#include <version>
145
146#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
147#pragma GCC system_header
148#endif
149
150_LIBCPP_BEGIN_NAMESPACE_STD
151
152#ifndef _LIBCPP_CXX03_LANG
153
154
155// __tuple_leaf
156
157template <size_t _Ip, class _Hp,
158          bool=is_empty<_Hp>::value && !__libcpp_is_final<_Hp>::value
159         >
160class __tuple_leaf;
161
162template <size_t _Ip, class _Hp, bool _Ep>
163inline _LIBCPP_INLINE_VISIBILITY
164void swap(__tuple_leaf<_Ip, _Hp, _Ep>& __x, __tuple_leaf<_Ip, _Hp, _Ep>& __y)
165    _NOEXCEPT_(__is_nothrow_swappable<_Hp>::value)
166{
167    swap(__x.get(), __y.get());
168}
169
170template <size_t _Ip, class _Hp, bool>
171class __tuple_leaf
172{
173    _Hp __value_;
174
175    template <class _Tp>
176    static constexpr bool __can_bind_reference() {
177#if __has_keyword(__reference_binds_to_temporary)
178      return !__reference_binds_to_temporary(_Hp, _Tp);
179#else
180      return true;
181#endif
182    }
183
184    __tuple_leaf& operator=(const __tuple_leaf&);
185public:
186    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR __tuple_leaf()
187             _NOEXCEPT_(is_nothrow_default_constructible<_Hp>::value) : __value_()
188       {static_assert(!is_reference<_Hp>::value,
189              "Attempted to default construct a reference element in a tuple");}
190
191    template <class _Alloc>
192        _LIBCPP_INLINE_VISIBILITY
193        __tuple_leaf(integral_constant<int, 0>, const _Alloc&)
194            : __value_()
195        {static_assert(!is_reference<_Hp>::value,
196              "Attempted to default construct a reference element in a tuple");}
197
198    template <class _Alloc>
199        _LIBCPP_INLINE_VISIBILITY
200        __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a)
201            : __value_(allocator_arg_t(), __a)
202        {static_assert(!is_reference<_Hp>::value,
203              "Attempted to default construct a reference element in a tuple");}
204
205    template <class _Alloc>
206        _LIBCPP_INLINE_VISIBILITY
207        __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a)
208            : __value_(__a)
209        {static_assert(!is_reference<_Hp>::value,
210              "Attempted to default construct a reference element in a tuple");}
211
212    template <class _Tp,
213              class = typename enable_if<
214                  __lazy_and<
215                      __lazy_not<is_same<typename __uncvref<_Tp>::type, __tuple_leaf>>
216                    , is_constructible<_Hp, _Tp>
217                    >::value
218                >::type
219            >
220        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
221        explicit __tuple_leaf(_Tp&& __t) _NOEXCEPT_((is_nothrow_constructible<_Hp, _Tp>::value))
222            : __value_(_VSTD::forward<_Tp>(__t))
223        {static_assert(__can_bind_reference<_Tp&&>(),
224       "Attempted construction of reference element binds to a temporary whose lifetime has ended");}
225
226    template <class _Tp, class _Alloc>
227        _LIBCPP_INLINE_VISIBILITY
228        explicit __tuple_leaf(integral_constant<int, 0>, const _Alloc&, _Tp&& __t)
229            : __value_(_VSTD::forward<_Tp>(__t))
230        {static_assert(__can_bind_reference<_Tp&&>(),
231       "Attempted construction of reference element binds to a temporary whose lifetime has ended");}
232
233    template <class _Tp, class _Alloc>
234        _LIBCPP_INLINE_VISIBILITY
235        explicit __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a, _Tp&& __t)
236            : __value_(allocator_arg_t(), __a, _VSTD::forward<_Tp>(__t))
237        {static_assert(!is_reference<_Hp>::value,
238            "Attempted to uses-allocator construct a reference element in a tuple");}
239
240    template <class _Tp, class _Alloc>
241        _LIBCPP_INLINE_VISIBILITY
242        explicit __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a, _Tp&& __t)
243            : __value_(_VSTD::forward<_Tp>(__t), __a)
244        {static_assert(!is_reference<_Hp>::value,
245           "Attempted to uses-allocator construct a reference element in a tuple");}
246
247    __tuple_leaf(const __tuple_leaf& __t) = default;
248    __tuple_leaf(__tuple_leaf&& __t) = default;
249
250    template <class _Tp>
251        _LIBCPP_INLINE_VISIBILITY
252        __tuple_leaf&
253        operator=(_Tp&& __t) _NOEXCEPT_((is_nothrow_assignable<_Hp&, _Tp>::value))
254        {
255            __value_ = _VSTD::forward<_Tp>(__t);
256            return *this;
257        }
258
259    _LIBCPP_INLINE_VISIBILITY
260    int swap(__tuple_leaf& __t) _NOEXCEPT_(__is_nothrow_swappable<__tuple_leaf>::value)
261    {
262        _VSTD::swap(*this, __t);
263        return 0;
264    }
265
266    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11       _Hp& get()       _NOEXCEPT {return __value_;}
267    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 const _Hp& get() const _NOEXCEPT {return __value_;}
268};
269
270template <size_t _Ip, class _Hp>
271class __tuple_leaf<_Ip, _Hp, true>
272    : private _Hp
273{
274
275    __tuple_leaf& operator=(const __tuple_leaf&);
276public:
277    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR __tuple_leaf()
278             _NOEXCEPT_(is_nothrow_default_constructible<_Hp>::value) {}
279
280    template <class _Alloc>
281        _LIBCPP_INLINE_VISIBILITY
282        __tuple_leaf(integral_constant<int, 0>, const _Alloc&) {}
283
284    template <class _Alloc>
285        _LIBCPP_INLINE_VISIBILITY
286        __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a)
287            : _Hp(allocator_arg_t(), __a) {}
288
289    template <class _Alloc>
290        _LIBCPP_INLINE_VISIBILITY
291        __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a)
292            : _Hp(__a) {}
293
294    template <class _Tp,
295              class = typename enable_if<
296                  __lazy_and<
297                        __lazy_not<is_same<typename __uncvref<_Tp>::type, __tuple_leaf>>
298                      , is_constructible<_Hp, _Tp>
299                    >::value
300                >::type
301            >
302        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
303        explicit __tuple_leaf(_Tp&& __t) _NOEXCEPT_((is_nothrow_constructible<_Hp, _Tp>::value))
304            : _Hp(_VSTD::forward<_Tp>(__t)) {}
305
306    template <class _Tp, class _Alloc>
307        _LIBCPP_INLINE_VISIBILITY
308        explicit __tuple_leaf(integral_constant<int, 0>, const _Alloc&, _Tp&& __t)
309            : _Hp(_VSTD::forward<_Tp>(__t)) {}
310
311    template <class _Tp, class _Alloc>
312        _LIBCPP_INLINE_VISIBILITY
313        explicit __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a, _Tp&& __t)
314            : _Hp(allocator_arg_t(), __a, _VSTD::forward<_Tp>(__t)) {}
315
316    template <class _Tp, class _Alloc>
317        _LIBCPP_INLINE_VISIBILITY
318        explicit __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a, _Tp&& __t)
319            : _Hp(_VSTD::forward<_Tp>(__t), __a) {}
320
321    __tuple_leaf(__tuple_leaf const &) = default;
322    __tuple_leaf(__tuple_leaf &&) = default;
323
324    template <class _Tp>
325        _LIBCPP_INLINE_VISIBILITY
326        __tuple_leaf&
327        operator=(_Tp&& __t) _NOEXCEPT_((is_nothrow_assignable<_Hp&, _Tp>::value))
328        {
329            _Hp::operator=(_VSTD::forward<_Tp>(__t));
330            return *this;
331        }
332
333    _LIBCPP_INLINE_VISIBILITY
334    int
335    swap(__tuple_leaf& __t) _NOEXCEPT_(__is_nothrow_swappable<__tuple_leaf>::value)
336    {
337        _VSTD::swap(*this, __t);
338        return 0;
339    }
340
341    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11       _Hp& get()       _NOEXCEPT {return static_cast<_Hp&>(*this);}
342    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 const _Hp& get() const _NOEXCEPT {return static_cast<const _Hp&>(*this);}
343};
344
345template <class ..._Tp>
346_LIBCPP_INLINE_VISIBILITY
347void __swallow(_Tp&&...) _NOEXCEPT {}
348
349template <class ..._Tp>
350struct __lazy_all : __all<_Tp::value...> {};
351
352template <class _Tp>
353struct __all_default_constructible;
354
355template <class ..._Tp>
356struct __all_default_constructible<__tuple_types<_Tp...>>
357    : __all<is_default_constructible<_Tp>::value...>
358{ };
359
360// __tuple_impl
361
362template<class _Indx, class ..._Tp> struct __tuple_impl;
363
364template<size_t ..._Indx, class ..._Tp>
365struct _LIBCPP_DECLSPEC_EMPTY_BASES __tuple_impl<__tuple_indices<_Indx...>, _Tp...>
366    : public __tuple_leaf<_Indx, _Tp>...
367{
368    _LIBCPP_INLINE_VISIBILITY
369    _LIBCPP_CONSTEXPR __tuple_impl()
370        _NOEXCEPT_(__all<is_nothrow_default_constructible<_Tp>::value...>::value) {}
371
372    template <size_t ..._Uf, class ..._Tf,
373              size_t ..._Ul, class ..._Tl, class ..._Up>
374        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
375        explicit
376        __tuple_impl(__tuple_indices<_Uf...>, __tuple_types<_Tf...>,
377                     __tuple_indices<_Ul...>, __tuple_types<_Tl...>,
378                     _Up&&... __u)
379                     _NOEXCEPT_((__all<is_nothrow_constructible<_Tf, _Up>::value...>::value &&
380                                 __all<is_nothrow_default_constructible<_Tl>::value...>::value)) :
381            __tuple_leaf<_Uf, _Tf>(_VSTD::forward<_Up>(__u))...,
382            __tuple_leaf<_Ul, _Tl>()...
383            {}
384
385    template <class _Alloc, size_t ..._Uf, class ..._Tf,
386              size_t ..._Ul, class ..._Tl, class ..._Up>
387        _LIBCPP_INLINE_VISIBILITY
388        explicit
389        __tuple_impl(allocator_arg_t, const _Alloc& __a,
390                     __tuple_indices<_Uf...>, __tuple_types<_Tf...>,
391                     __tuple_indices<_Ul...>, __tuple_types<_Tl...>,
392                     _Up&&... __u) :
393            __tuple_leaf<_Uf, _Tf>(__uses_alloc_ctor<_Tf, _Alloc, _Up>(), __a,
394            _VSTD::forward<_Up>(__u))...,
395            __tuple_leaf<_Ul, _Tl>(__uses_alloc_ctor<_Tl, _Alloc>(), __a)...
396            {}
397
398    template <class _Tuple,
399              class = typename enable_if
400                      <
401                         __tuple_constructible<_Tuple, tuple<_Tp...> >::value
402                      >::type
403             >
404        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
405        __tuple_impl(_Tuple&& __t) _NOEXCEPT_((__all<is_nothrow_constructible<_Tp, typename tuple_element<_Indx,
406                                       typename __make_tuple_types<_Tuple>::type>::type>::value...>::value))
407            : __tuple_leaf<_Indx, _Tp>(_VSTD::forward<typename tuple_element<_Indx,
408                                       typename __make_tuple_types<_Tuple>::type>::type>(_VSTD::get<_Indx>(__t)))...
409            {}
410
411    template <class _Alloc, class _Tuple,
412              class = typename enable_if
413                      <
414                         __tuple_constructible<_Tuple, tuple<_Tp...> >::value
415                      >::type
416             >
417        _LIBCPP_INLINE_VISIBILITY
418        __tuple_impl(allocator_arg_t, const _Alloc& __a, _Tuple&& __t)
419            : __tuple_leaf<_Indx, _Tp>(__uses_alloc_ctor<_Tp, _Alloc, typename tuple_element<_Indx,
420                                       typename __make_tuple_types<_Tuple>::type>::type>(), __a,
421                                       _VSTD::forward<typename tuple_element<_Indx,
422                                       typename __make_tuple_types<_Tuple>::type>::type>(_VSTD::get<_Indx>(__t)))...
423            {}
424
425    template <class _Tuple>
426        _LIBCPP_INLINE_VISIBILITY
427        typename enable_if
428        <
429            __tuple_assignable<_Tuple, tuple<_Tp...> >::value,
430            __tuple_impl&
431        >::type
432        operator=(_Tuple&& __t) _NOEXCEPT_((__all<is_nothrow_assignable<_Tp&, typename tuple_element<_Indx,
433                                       typename __make_tuple_types<_Tuple>::type>::type>::value...>::value))
434        {
435            __swallow(__tuple_leaf<_Indx, _Tp>::operator=(_VSTD::forward<typename tuple_element<_Indx,
436                                       typename __make_tuple_types<_Tuple>::type>::type>(_VSTD::get<_Indx>(__t)))...);
437            return *this;
438        }
439
440    __tuple_impl(const __tuple_impl&) = default;
441    __tuple_impl(__tuple_impl&&) = default;
442
443    _LIBCPP_INLINE_VISIBILITY
444    __tuple_impl&
445    operator=(const __tuple_impl& __t) _NOEXCEPT_((__all<is_nothrow_copy_assignable<_Tp>::value...>::value))
446    {
447        __swallow(__tuple_leaf<_Indx, _Tp>::operator=(static_cast<const __tuple_leaf<_Indx, _Tp>&>(__t).get())...);
448        return *this;
449    }
450
451    _LIBCPP_INLINE_VISIBILITY
452    __tuple_impl&
453    operator=(__tuple_impl&& __t) _NOEXCEPT_((__all<is_nothrow_move_assignable<_Tp>::value...>::value))
454    {
455        __swallow(__tuple_leaf<_Indx, _Tp>::operator=(_VSTD::forward<_Tp>(static_cast<__tuple_leaf<_Indx, _Tp>&>(__t).get()))...);
456        return *this;
457    }
458
459    _LIBCPP_INLINE_VISIBILITY
460    void swap(__tuple_impl& __t)
461        _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
462    {
463        __swallow(__tuple_leaf<_Indx, _Tp>::swap(static_cast<__tuple_leaf<_Indx, _Tp>&>(__t))...);
464    }
465};
466
467
468
469template <class ..._Tp>
470class _LIBCPP_TEMPLATE_VIS tuple
471{
472    typedef __tuple_impl<typename __make_tuple_indices<sizeof...(_Tp)>::type, _Tp...> _BaseT;
473
474    _BaseT __base_;
475
476#if defined(_LIBCPP_ENABLE_TUPLE_IMPLICIT_REDUCED_ARITY_EXTENSION)
477    static constexpr bool _EnableImplicitReducedArityExtension = true;
478#else
479    static constexpr bool _EnableImplicitReducedArityExtension = false;
480#endif
481
482    template <class ..._Args>
483    struct _PackExpandsToThisTuple : false_type {};
484
485    template <class _Arg>
486    struct _PackExpandsToThisTuple<_Arg>
487        : is_same<typename __uncvref<_Arg>::type, tuple> {};
488
489    template <bool _MaybeEnable, class _Dummy = void>
490    struct _CheckArgsConstructor : __check_tuple_constructor_fail {};
491
492    template <class _Dummy>
493    struct _CheckArgsConstructor<true, _Dummy>
494    {
495        template <class ..._Args>
496        static constexpr bool __enable_default() {
497            return __all<is_default_constructible<_Args>::value...>::value;
498        }
499
500        template <class ..._Args>
501        static constexpr bool __enable_explicit() {
502            return
503                __tuple_constructible<
504                    tuple<_Args...>,
505                    typename __make_tuple_types<tuple,
506                             sizeof...(_Args) < sizeof...(_Tp) ?
507                                 sizeof...(_Args) :
508                                 sizeof...(_Tp)>::type
509                >::value &&
510                !__tuple_convertible<
511                    tuple<_Args...>,
512                    typename __make_tuple_types<tuple,
513                             sizeof...(_Args) < sizeof...(_Tp) ?
514                                 sizeof...(_Args) :
515                                 sizeof...(_Tp)>::type
516                >::value &&
517                __all_default_constructible<
518                    typename __make_tuple_types<tuple, sizeof...(_Tp),
519                             sizeof...(_Args) < sizeof...(_Tp) ?
520                                 sizeof...(_Args) :
521                                 sizeof...(_Tp)>::type
522                >::value;
523        }
524
525        template <class ..._Args>
526        static constexpr bool __enable_implicit() {
527            return
528                __tuple_convertible<
529                    tuple<_Args...>,
530                    typename __make_tuple_types<tuple,
531                             sizeof...(_Args) < sizeof...(_Tp) ?
532                                 sizeof...(_Args) :
533                                 sizeof...(_Tp)>::type
534                >::value &&
535                __all_default_constructible<
536                    typename __make_tuple_types<tuple, sizeof...(_Tp),
537                             sizeof...(_Args) < sizeof...(_Tp) ?
538                                 sizeof...(_Args) :
539                                 sizeof...(_Tp)>::type
540                >::value;
541        }
542    };
543
544    template <bool _MaybeEnable,
545              bool = sizeof...(_Tp) == 1,
546              class _Dummy = void>
547    struct _CheckTupleLikeConstructor : __check_tuple_constructor_fail {};
548
549    template <class _Dummy>
550    struct _CheckTupleLikeConstructor<true, false, _Dummy>
551    {
552        template <class _Tuple>
553        static constexpr bool __enable_implicit() {
554            return __tuple_convertible<_Tuple, tuple>::value;
555        }
556
557        template <class _Tuple>
558        static constexpr bool __enable_explicit() {
559            return __tuple_constructible<_Tuple, tuple>::value
560               && !__tuple_convertible<_Tuple, tuple>::value;
561        }
562    };
563
564    template <class _Dummy>
565    struct _CheckTupleLikeConstructor<true, true, _Dummy>
566    {
567        // This trait is used to disable the tuple-like constructor when
568        // the UTypes... constructor should be selected instead.
569        // See LWG issue #2549.
570        template <class _Tuple>
571        using _PreferTupleLikeConstructor = __lazy_or<
572            // Don't attempt the two checks below if the tuple we are given
573            // has the same type as this tuple.
574            is_same<typename __uncvref<_Tuple>::type, tuple>,
575            __lazy_and<
576                __lazy_not<is_constructible<_Tp..., _Tuple>>,
577                __lazy_not<is_convertible<_Tuple, _Tp...>>
578            >
579        >;
580
581        template <class _Tuple>
582        static constexpr bool __enable_implicit() {
583            return __lazy_and<
584                __tuple_convertible<_Tuple, tuple>,
585                _PreferTupleLikeConstructor<_Tuple>
586            >::value;
587        }
588
589        template <class _Tuple>
590        static constexpr bool __enable_explicit() {
591            return __lazy_and<
592                __tuple_constructible<_Tuple, tuple>,
593                _PreferTupleLikeConstructor<_Tuple>,
594                __lazy_not<__tuple_convertible<_Tuple, tuple>>
595            >::value;
596        }
597    };
598
599    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
600        typename tuple_element<_Jp, tuple<_Up...> >::type& get(tuple<_Up...>&) _NOEXCEPT;
601    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
602        const typename tuple_element<_Jp, tuple<_Up...> >::type& get(const tuple<_Up...>&) _NOEXCEPT;
603    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
604        typename tuple_element<_Jp, tuple<_Up...> >::type&& get(tuple<_Up...>&&) _NOEXCEPT;
605    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
606        const typename tuple_element<_Jp, tuple<_Up...> >::type&& get(const tuple<_Up...>&&) _NOEXCEPT;
607public:
608
609    template <bool _Dummy = true, class = typename enable_if<
610        _CheckArgsConstructor<_Dummy>::template __enable_default<_Tp...>()
611    >::type>
612    _LIBCPP_INLINE_VISIBILITY
613    _LIBCPP_CONSTEXPR tuple()
614        _NOEXCEPT_(__all<is_nothrow_default_constructible<_Tp>::value...>::value) {}
615
616    tuple(tuple const&) = default;
617    tuple(tuple&&) = default;
618
619    template <class _AllocArgT, class _Alloc, bool _Dummy = true, class = typename enable_if<
620        __lazy_and<
621            is_same<allocator_arg_t, _AllocArgT>,
622            __lazy_all<__dependent_type<is_default_constructible<_Tp>, _Dummy>...>
623       >::value
624    >::type>
625    _LIBCPP_INLINE_VISIBILITY
626    tuple(_AllocArgT, _Alloc const& __a)
627      : __base_(allocator_arg_t(), __a,
628                    __tuple_indices<>(), __tuple_types<>(),
629                    typename __make_tuple_indices<sizeof...(_Tp), 0>::type(),
630                    __tuple_types<_Tp...>()) {}
631
632    template <bool _Dummy = true,
633              typename enable_if
634                      <
635                         _CheckArgsConstructor<
636                            _Dummy
637                         >::template __enable_implicit<_Tp const&...>(),
638                         bool
639                      >::type = false
640        >
641    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
642    tuple(const _Tp& ... __t) _NOEXCEPT_((__all<is_nothrow_copy_constructible<_Tp>::value...>::value))
643        : __base_(typename __make_tuple_indices<sizeof...(_Tp)>::type(),
644                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
645                typename __make_tuple_indices<0>::type(),
646                typename __make_tuple_types<tuple, 0>::type(),
647                __t...
648               ) {}
649
650    template <bool _Dummy = true,
651              typename enable_if
652                      <
653                         _CheckArgsConstructor<
654                            _Dummy
655                         >::template __enable_explicit<_Tp const&...>(),
656                         bool
657                      >::type = false
658        >
659    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
660    explicit tuple(const _Tp& ... __t) _NOEXCEPT_((__all<is_nothrow_copy_constructible<_Tp>::value...>::value))
661        : __base_(typename __make_tuple_indices<sizeof...(_Tp)>::type(),
662                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
663                typename __make_tuple_indices<0>::type(),
664                typename __make_tuple_types<tuple, 0>::type(),
665                __t...
666               ) {}
667
668    template <class _Alloc, bool _Dummy = true,
669              typename enable_if
670                      <
671                         _CheckArgsConstructor<
672                            _Dummy
673                         >::template __enable_implicit<_Tp const&...>(),
674                         bool
675                      >::type = false
676        >
677      _LIBCPP_INLINE_VISIBILITY
678      tuple(allocator_arg_t, const _Alloc& __a, const _Tp& ... __t)
679        : __base_(allocator_arg_t(), __a,
680                typename __make_tuple_indices<sizeof...(_Tp)>::type(),
681                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
682                typename __make_tuple_indices<0>::type(),
683                typename __make_tuple_types<tuple, 0>::type(),
684                __t...
685               ) {}
686
687    template <class _Alloc, bool _Dummy = true,
688              typename enable_if
689                      <
690                         _CheckArgsConstructor<
691                            _Dummy
692                         >::template __enable_explicit<_Tp const&...>(),
693                         bool
694                      >::type = false
695        >
696      _LIBCPP_INLINE_VISIBILITY
697      explicit
698      tuple(allocator_arg_t, const _Alloc& __a, const _Tp& ... __t)
699        : __base_(allocator_arg_t(), __a,
700                typename __make_tuple_indices<sizeof...(_Tp)>::type(),
701                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
702                typename __make_tuple_indices<0>::type(),
703                typename __make_tuple_types<tuple, 0>::type(),
704                __t...
705               ) {}
706
707    template <class ..._Up,
708              bool _PackIsTuple = _PackExpandsToThisTuple<_Up...>::value,
709              typename enable_if
710                      <
711                         _CheckArgsConstructor<
712                             sizeof...(_Up) == sizeof...(_Tp)
713                             && !_PackIsTuple
714                         >::template __enable_implicit<_Up...>() ||
715                        _CheckArgsConstructor<
716                            _EnableImplicitReducedArityExtension
717                            && sizeof...(_Up) < sizeof...(_Tp)
718                            && !_PackIsTuple
719                         >::template __enable_implicit<_Up...>(),
720                         bool
721                      >::type = false
722             >
723        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
724        tuple(_Up&&... __u)
725            _NOEXCEPT_((
726                is_nothrow_constructible<_BaseT,
727                    typename __make_tuple_indices<sizeof...(_Up)>::type,
728                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type,
729                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type,
730                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type,
731                    _Up...
732                >::value
733            ))
734            : __base_(typename __make_tuple_indices<sizeof...(_Up)>::type(),
735                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
736                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
737                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
738                    _VSTD::forward<_Up>(__u)...) {}
739
740    template <class ..._Up,
741              typename enable_if
742                      <
743                         _CheckArgsConstructor<
744                             sizeof...(_Up) <= sizeof...(_Tp)
745                             && !_PackExpandsToThisTuple<_Up...>::value
746                         >::template __enable_explicit<_Up...>() ||
747                         _CheckArgsConstructor<
748                            !_EnableImplicitReducedArityExtension
749                            && sizeof...(_Up) < sizeof...(_Tp)
750                            && !_PackExpandsToThisTuple<_Up...>::value
751                         >::template __enable_implicit<_Up...>(),
752                         bool
753                      >::type = false
754             >
755        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
756        explicit
757        tuple(_Up&&... __u)
758            _NOEXCEPT_((
759                is_nothrow_constructible<_BaseT,
760                    typename __make_tuple_indices<sizeof...(_Up)>::type,
761                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type,
762                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type,
763                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type,
764                    _Up...
765                >::value
766            ))
767            : __base_(typename __make_tuple_indices<sizeof...(_Up)>::type(),
768                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
769                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
770                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
771                    _VSTD::forward<_Up>(__u)...) {}
772
773    template <class _Alloc, class ..._Up,
774              typename enable_if
775                      <
776                         _CheckArgsConstructor<
777                             sizeof...(_Up) == sizeof...(_Tp) &&
778                             !_PackExpandsToThisTuple<_Up...>::value
779                         >::template __enable_implicit<_Up...>(),
780                         bool
781                      >::type = false
782             >
783        _LIBCPP_INLINE_VISIBILITY
784        tuple(allocator_arg_t, const _Alloc& __a, _Up&&... __u)
785            : __base_(allocator_arg_t(), __a,
786                    typename __make_tuple_indices<sizeof...(_Up)>::type(),
787                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
788                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
789                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
790                    _VSTD::forward<_Up>(__u)...) {}
791
792    template <class _Alloc, class ..._Up,
793              typename enable_if
794                      <
795                         _CheckArgsConstructor<
796                             sizeof...(_Up) == sizeof...(_Tp) &&
797                             !_PackExpandsToThisTuple<_Up...>::value
798                         >::template __enable_explicit<_Up...>(),
799                         bool
800                      >::type = false
801             >
802        _LIBCPP_INLINE_VISIBILITY
803        explicit
804        tuple(allocator_arg_t, const _Alloc& __a, _Up&&... __u)
805            : __base_(allocator_arg_t(), __a,
806                    typename __make_tuple_indices<sizeof...(_Up)>::type(),
807                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
808                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
809                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
810                    _VSTD::forward<_Up>(__u)...) {}
811
812    template <class _Tuple,
813              typename enable_if
814                      <
815                         _CheckTupleLikeConstructor<
816                             __tuple_like_with_size<_Tuple, sizeof...(_Tp)>::value
817                             && !_PackExpandsToThisTuple<_Tuple>::value
818                         >::template __enable_implicit<_Tuple>(),
819                         bool
820                      >::type = false
821             >
822        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
823        tuple(_Tuple&& __t) _NOEXCEPT_((is_nothrow_constructible<_BaseT, _Tuple>::value))
824            : __base_(_VSTD::forward<_Tuple>(__t)) {}
825
826    template <class _Tuple,
827              typename enable_if
828                      <
829                         _CheckTupleLikeConstructor<
830                             __tuple_like_with_size<_Tuple, sizeof...(_Tp)>::value
831                             && !_PackExpandsToThisTuple<_Tuple>::value
832                         >::template __enable_explicit<_Tuple>(),
833                         bool
834                      >::type = false
835             >
836        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
837        explicit
838        tuple(_Tuple&& __t) _NOEXCEPT_((is_nothrow_constructible<_BaseT, _Tuple>::value))
839            : __base_(_VSTD::forward<_Tuple>(__t)) {}
840
841    template <class _Alloc, class _Tuple,
842              typename enable_if
843                      <
844                         _CheckTupleLikeConstructor<
845                             __tuple_like_with_size<_Tuple, sizeof...(_Tp)>::value
846                         >::template __enable_implicit<_Tuple>(),
847                         bool
848                      >::type = false
849             >
850        _LIBCPP_INLINE_VISIBILITY
851        tuple(allocator_arg_t, const _Alloc& __a, _Tuple&& __t)
852            : __base_(allocator_arg_t(), __a, _VSTD::forward<_Tuple>(__t)) {}
853
854    template <class _Alloc, class _Tuple,
855              typename enable_if
856                      <
857                         _CheckTupleLikeConstructor<
858                             __tuple_like_with_size<_Tuple, sizeof...(_Tp)>::value
859                         >::template __enable_explicit<_Tuple>(),
860                         bool
861                      >::type = false
862             >
863        _LIBCPP_INLINE_VISIBILITY
864        explicit
865        tuple(allocator_arg_t, const _Alloc& __a, _Tuple&& __t)
866            : __base_(allocator_arg_t(), __a, _VSTD::forward<_Tuple>(__t)) {}
867
868    using _CanCopyAssign = __all<is_copy_assignable<_Tp>::value...>;
869    using _CanMoveAssign = __all<is_move_assignable<_Tp>::value...>;
870
871    _LIBCPP_INLINE_VISIBILITY
872    tuple& operator=(typename conditional<_CanCopyAssign::value, tuple, __nat>::type const& __t)
873        _NOEXCEPT_((__all<is_nothrow_copy_assignable<_Tp>::value...>::value))
874    {
875        __base_.operator=(__t.__base_);
876        return *this;
877    }
878
879    _LIBCPP_INLINE_VISIBILITY
880    tuple& operator=(typename conditional<_CanMoveAssign::value, tuple, __nat>::type&& __t)
881        _NOEXCEPT_((__all<is_nothrow_move_assignable<_Tp>::value...>::value))
882    {
883        __base_.operator=(static_cast<_BaseT&&>(__t.__base_));
884        return *this;
885    }
886
887    template <class _Tuple,
888              class = typename enable_if
889                      <
890                         __tuple_assignable<_Tuple, tuple>::value
891                      >::type
892             >
893        _LIBCPP_INLINE_VISIBILITY
894        tuple&
895        operator=(_Tuple&& __t) _NOEXCEPT_((is_nothrow_assignable<_BaseT&, _Tuple>::value))
896        {
897            __base_.operator=(_VSTD::forward<_Tuple>(__t));
898            return *this;
899        }
900
901    _LIBCPP_INLINE_VISIBILITY
902    void swap(tuple& __t) _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
903        {__base_.swap(__t.__base_);}
904};
905
906template <>
907class _LIBCPP_TEMPLATE_VIS tuple<>
908{
909public:
910    _LIBCPP_INLINE_VISIBILITY
911    _LIBCPP_CONSTEXPR tuple() _NOEXCEPT {}
912    template <class _Alloc>
913    _LIBCPP_INLINE_VISIBILITY
914        tuple(allocator_arg_t, const _Alloc&) _NOEXCEPT {}
915    template <class _Alloc>
916    _LIBCPP_INLINE_VISIBILITY
917        tuple(allocator_arg_t, const _Alloc&, const tuple&) _NOEXCEPT {}
918    template <class _Up>
919    _LIBCPP_INLINE_VISIBILITY
920        tuple(array<_Up, 0>) _NOEXCEPT {}
921    template <class _Alloc, class _Up>
922    _LIBCPP_INLINE_VISIBILITY
923        tuple(allocator_arg_t, const _Alloc&, array<_Up, 0>) _NOEXCEPT {}
924    _LIBCPP_INLINE_VISIBILITY
925    void swap(tuple&) _NOEXCEPT {}
926};
927
928#ifndef _LIBCPP_HAS_NO_DEDUCTION_GUIDES
929// NOTE: These are not yet standardized, but are required to simulate the
930// implicit deduction guide that should be generated had libc++ declared the
931// tuple-like constructors "correctly"
932template <class _Alloc, class ..._Args>
933tuple(allocator_arg_t, const _Alloc&, tuple<_Args...> const&) -> tuple<_Args...>;
934template <class _Alloc, class ..._Args>
935tuple(allocator_arg_t, const _Alloc&, tuple<_Args...>&&) -> tuple<_Args...>;
936#endif
937
938template <class ..._Tp>
939inline _LIBCPP_INLINE_VISIBILITY
940typename enable_if
941<
942    __all<__is_swappable<_Tp>::value...>::value,
943    void
944>::type
945swap(tuple<_Tp...>& __t, tuple<_Tp...>& __u)
946                 _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
947    {__t.swap(__u);}
948
949// get
950
951template <size_t _Ip, class ..._Tp>
952inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
953typename tuple_element<_Ip, tuple<_Tp...> >::type&
954get(tuple<_Tp...>& __t) _NOEXCEPT
955{
956    typedef typename tuple_element<_Ip, tuple<_Tp...> >::type type;
957    return static_cast<__tuple_leaf<_Ip, type>&>(__t.__base_).get();
958}
959
960template <size_t _Ip, class ..._Tp>
961inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
962const typename tuple_element<_Ip, tuple<_Tp...> >::type&
963get(const tuple<_Tp...>& __t) _NOEXCEPT
964{
965    typedef typename tuple_element<_Ip, tuple<_Tp...> >::type type;
966    return static_cast<const __tuple_leaf<_Ip, type>&>(__t.__base_).get();
967}
968
969template <size_t _Ip, class ..._Tp>
970inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
971typename tuple_element<_Ip, tuple<_Tp...> >::type&&
972get(tuple<_Tp...>&& __t) _NOEXCEPT
973{
974    typedef typename tuple_element<_Ip, tuple<_Tp...> >::type type;
975    return static_cast<type&&>(
976             static_cast<__tuple_leaf<_Ip, type>&&>(__t.__base_).get());
977}
978
979template <size_t _Ip, class ..._Tp>
980inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
981const typename tuple_element<_Ip, tuple<_Tp...> >::type&&
982get(const tuple<_Tp...>&& __t) _NOEXCEPT
983{
984    typedef typename tuple_element<_Ip, tuple<_Tp...> >::type type;
985    return static_cast<const type&&>(
986             static_cast<const __tuple_leaf<_Ip, type>&&>(__t.__base_).get());
987}
988
989#if _LIBCPP_STD_VER > 11
990
991namespace __find_detail {
992
993static constexpr size_t __not_found = -1;
994static constexpr size_t __ambiguous = __not_found - 1;
995
996inline _LIBCPP_INLINE_VISIBILITY
997constexpr size_t __find_idx_return(size_t __curr_i, size_t __res, bool __matches) {
998    return !__matches ? __res :
999        (__res == __not_found ? __curr_i : __ambiguous);
1000}
1001
1002template <size_t _Nx>
1003inline _LIBCPP_INLINE_VISIBILITY
1004constexpr size_t __find_idx(size_t __i, const bool (&__matches)[_Nx]) {
1005  return __i == _Nx ? __not_found :
1006      __find_idx_return(__i, __find_idx(__i + 1, __matches), __matches[__i]);
1007}
1008
1009template <class _T1, class ..._Args>
1010struct __find_exactly_one_checked {
1011    static constexpr bool __matches[sizeof...(_Args)] = {is_same<_T1, _Args>::value...};
1012    static constexpr size_t value = __find_detail::__find_idx(0, __matches);
1013    static_assert(value != __not_found, "type not found in type list" );
1014    static_assert(value != __ambiguous, "type occurs more than once in type list");
1015};
1016
1017template <class _T1>
1018struct __find_exactly_one_checked<_T1> {
1019    static_assert(!is_same<_T1, _T1>::value, "type not in empty type list");
1020};
1021
1022} // namespace __find_detail;
1023
1024template <typename _T1, typename... _Args>
1025struct __find_exactly_one_t
1026    : public __find_detail::__find_exactly_one_checked<_T1, _Args...> {
1027};
1028
1029template <class _T1, class... _Args>
1030inline _LIBCPP_INLINE_VISIBILITY
1031constexpr _T1& get(tuple<_Args...>& __tup) noexcept
1032{
1033    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(__tup);
1034}
1035
1036template <class _T1, class... _Args>
1037inline _LIBCPP_INLINE_VISIBILITY
1038constexpr _T1 const& get(tuple<_Args...> const& __tup) noexcept
1039{
1040    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(__tup);
1041}
1042
1043template <class _T1, class... _Args>
1044inline _LIBCPP_INLINE_VISIBILITY
1045constexpr _T1&& get(tuple<_Args...>&& __tup) noexcept
1046{
1047    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(_VSTD::move(__tup));
1048}
1049
1050template <class _T1, class... _Args>
1051inline _LIBCPP_INLINE_VISIBILITY
1052constexpr _T1 const&& get(tuple<_Args...> const&& __tup) noexcept
1053{
1054    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(_VSTD::move(__tup));
1055}
1056
1057#endif
1058
1059// tie
1060
1061template <class ..._Tp>
1062inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1063tuple<_Tp&...>
1064tie(_Tp&... __t) _NOEXCEPT
1065{
1066    return tuple<_Tp&...>(__t...);
1067}
1068
1069template <class _Up>
1070struct __ignore_t
1071{
1072    template <class _Tp>
1073    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1074    const __ignore_t& operator=(_Tp&&) const {return *this;}
1075};
1076
1077namespace {
1078  _LIBCPP_INLINE_VAR constexpr __ignore_t<unsigned char> ignore = __ignore_t<unsigned char>();
1079}
1080
1081template <class... _Tp>
1082inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1083tuple<typename __unwrap_ref_decay<_Tp>::type...>
1084make_tuple(_Tp&&... __t)
1085{
1086    return tuple<typename __unwrap_ref_decay<_Tp>::type...>(_VSTD::forward<_Tp>(__t)...);
1087}
1088
1089template <class... _Tp>
1090inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1091tuple<_Tp&&...>
1092forward_as_tuple(_Tp&&... __t) _NOEXCEPT
1093{
1094    return tuple<_Tp&&...>(_VSTD::forward<_Tp>(__t)...);
1095}
1096
1097template <size_t _Ip>
1098struct __tuple_equal
1099{
1100    template <class _Tp, class _Up>
1101    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1102    bool operator()(const _Tp& __x, const _Up& __y)
1103    {
1104        return __tuple_equal<_Ip - 1>()(__x, __y) && _VSTD::get<_Ip-1>(__x) == _VSTD::get<_Ip-1>(__y);
1105    }
1106};
1107
1108template <>
1109struct __tuple_equal<0>
1110{
1111    template <class _Tp, class _Up>
1112    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1113    bool operator()(const _Tp&, const _Up&)
1114    {
1115        return true;
1116    }
1117};
1118
1119template <class ..._Tp, class ..._Up>
1120inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1121bool
1122operator==(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1123{
1124    return __tuple_equal<sizeof...(_Tp)>()(__x, __y);
1125}
1126
1127template <class ..._Tp, class ..._Up>
1128inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1129bool
1130operator!=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1131{
1132    return !(__x == __y);
1133}
1134
1135template <size_t _Ip>
1136struct __tuple_less
1137{
1138    template <class _Tp, class _Up>
1139    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1140    bool operator()(const _Tp& __x, const _Up& __y)
1141    {
1142        const size_t __idx = tuple_size<_Tp>::value - _Ip;
1143        if (_VSTD::get<__idx>(__x) < _VSTD::get<__idx>(__y))
1144            return true;
1145        if (_VSTD::get<__idx>(__y) < _VSTD::get<__idx>(__x))
1146            return false;
1147        return __tuple_less<_Ip-1>()(__x, __y);
1148    }
1149};
1150
1151template <>
1152struct __tuple_less<0>
1153{
1154    template <class _Tp, class _Up>
1155    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1156    bool operator()(const _Tp&, const _Up&)
1157    {
1158        return false;
1159    }
1160};
1161
1162template <class ..._Tp, class ..._Up>
1163inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1164bool
1165operator<(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1166{
1167    return __tuple_less<sizeof...(_Tp)>()(__x, __y);
1168}
1169
1170template <class ..._Tp, class ..._Up>
1171inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1172bool
1173operator>(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1174{
1175    return __y < __x;
1176}
1177
1178template <class ..._Tp, class ..._Up>
1179inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1180bool
1181operator>=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1182{
1183    return !(__x < __y);
1184}
1185
1186template <class ..._Tp, class ..._Up>
1187inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1188bool
1189operator<=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1190{
1191    return !(__y < __x);
1192}
1193
1194// tuple_cat
1195
1196template <class _Tp, class _Up> struct __tuple_cat_type;
1197
1198template <class ..._Ttypes, class ..._Utypes>
1199struct __tuple_cat_type<tuple<_Ttypes...>, __tuple_types<_Utypes...> >
1200{
1201    typedef tuple<_Ttypes..., _Utypes...> type;
1202};
1203
1204template <class _ResultTuple, bool _Is_Tuple0TupleLike, class ..._Tuples>
1205struct __tuple_cat_return_1
1206{
1207};
1208
1209template <class ..._Types, class _Tuple0>
1210struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0>
1211{
1212    typedef typename __tuple_cat_type<tuple<_Types...>,
1213            typename __make_tuple_types<typename remove_reference<_Tuple0>::type>::type>::type
1214                                                                           type;
1215};
1216
1217template <class ..._Types, class _Tuple0, class _Tuple1, class ..._Tuples>
1218struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0, _Tuple1, _Tuples...>
1219    : public __tuple_cat_return_1<
1220                 typename __tuple_cat_type<
1221                     tuple<_Types...>,
1222                     typename __make_tuple_types<typename remove_reference<_Tuple0>::type>::type
1223                 >::type,
1224                 __tuple_like<typename remove_reference<_Tuple1>::type>::value,
1225                 _Tuple1, _Tuples...>
1226{
1227};
1228
1229template <class ..._Tuples> struct __tuple_cat_return;
1230
1231template <class _Tuple0, class ..._Tuples>
1232struct __tuple_cat_return<_Tuple0, _Tuples...>
1233    : public __tuple_cat_return_1<tuple<>,
1234         __tuple_like<typename remove_reference<_Tuple0>::type>::value, _Tuple0,
1235                                                                     _Tuples...>
1236{
1237};
1238
1239template <>
1240struct __tuple_cat_return<>
1241{
1242    typedef tuple<> type;
1243};
1244
1245inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1246tuple<>
1247tuple_cat()
1248{
1249    return tuple<>();
1250}
1251
1252template <class _Rp, class _Indices, class _Tuple0, class ..._Tuples>
1253struct __tuple_cat_return_ref_imp;
1254
1255template <class ..._Types, size_t ..._I0, class _Tuple0>
1256struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>, _Tuple0>
1257{
1258    typedef typename remove_reference<_Tuple0>::type _T0;
1259    typedef tuple<_Types..., typename __apply_cv<_Tuple0,
1260                          typename tuple_element<_I0, _T0>::type>::type&&...> type;
1261};
1262
1263template <class ..._Types, size_t ..._I0, class _Tuple0, class _Tuple1, class ..._Tuples>
1264struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>,
1265                                  _Tuple0, _Tuple1, _Tuples...>
1266    : public __tuple_cat_return_ref_imp<
1267         tuple<_Types..., typename __apply_cv<_Tuple0,
1268               typename tuple_element<_I0,
1269                  typename remove_reference<_Tuple0>::type>::type>::type&&...>,
1270         typename __make_tuple_indices<tuple_size<typename
1271                                 remove_reference<_Tuple1>::type>::value>::type,
1272         _Tuple1, _Tuples...>
1273{
1274};
1275
1276template <class _Tuple0, class ..._Tuples>
1277struct __tuple_cat_return_ref
1278    : public __tuple_cat_return_ref_imp<tuple<>,
1279               typename __make_tuple_indices<
1280                        tuple_size<typename remove_reference<_Tuple0>::type>::value
1281               >::type, _Tuple0, _Tuples...>
1282{
1283};
1284
1285template <class _Types, class _I0, class _J0>
1286struct __tuple_cat;
1287
1288template <class ..._Types, size_t ..._I0, size_t ..._J0>
1289struct __tuple_cat<tuple<_Types...>, __tuple_indices<_I0...>, __tuple_indices<_J0...> >
1290{
1291    template <class _Tuple0>
1292    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1293    typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&>::type
1294    operator()(tuple<_Types...> __t, _Tuple0&& __t0)
1295    {
1296        return forward_as_tuple(_VSTD::forward<_Types>(_VSTD::get<_I0>(__t))...,
1297                                      _VSTD::get<_J0>(_VSTD::forward<_Tuple0>(__t0))...);
1298    }
1299
1300    template <class _Tuple0, class _Tuple1, class ..._Tuples>
1301    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1302    typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&, _Tuple1&&, _Tuples&&...>::type
1303    operator()(tuple<_Types...> __t, _Tuple0&& __t0, _Tuple1&& __t1, _Tuples&& ...__tpls)
1304    {
1305        typedef typename remove_reference<_Tuple0>::type _T0;
1306        typedef typename remove_reference<_Tuple1>::type _T1;
1307        return __tuple_cat<
1308           tuple<_Types..., typename __apply_cv<_Tuple0, typename tuple_element<_J0, _T0>::type>::type&&...>,
1309           typename __make_tuple_indices<sizeof ...(_Types) + tuple_size<_T0>::value>::type,
1310           typename __make_tuple_indices<tuple_size<_T1>::value>::type>()
1311                           (forward_as_tuple(
1312                              _VSTD::forward<_Types>(_VSTD::get<_I0>(__t))...,
1313                              _VSTD::get<_J0>(_VSTD::forward<_Tuple0>(__t0))...
1314                            ),
1315                            _VSTD::forward<_Tuple1>(__t1),
1316                            _VSTD::forward<_Tuples>(__tpls)...);
1317    }
1318};
1319
1320template <class _Tuple0, class... _Tuples>
1321inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1322typename __tuple_cat_return<_Tuple0, _Tuples...>::type
1323tuple_cat(_Tuple0&& __t0, _Tuples&&... __tpls)
1324{
1325    typedef typename remove_reference<_Tuple0>::type _T0;
1326    return __tuple_cat<tuple<>, __tuple_indices<>,
1327                  typename __make_tuple_indices<tuple_size<_T0>::value>::type>()
1328                  (tuple<>(), _VSTD::forward<_Tuple0>(__t0),
1329                                            _VSTD::forward<_Tuples>(__tpls)...);
1330}
1331
1332template <class ..._Tp, class _Alloc>
1333struct _LIBCPP_TEMPLATE_VIS uses_allocator<tuple<_Tp...>, _Alloc>
1334    : true_type {};
1335
1336template <class _T1, class _T2>
1337template <class... _Args1, class... _Args2, size_t ..._I1, size_t ..._I2>
1338inline _LIBCPP_INLINE_VISIBILITY
1339pair<_T1, _T2>::pair(piecewise_construct_t,
1340                     tuple<_Args1...>& __first_args, tuple<_Args2...>& __second_args,
1341                     __tuple_indices<_I1...>, __tuple_indices<_I2...>)
1342    :  first(_VSTD::forward<_Args1>(_VSTD::get<_I1>( __first_args))...),
1343      second(_VSTD::forward<_Args2>(_VSTD::get<_I2>(__second_args))...)
1344{
1345}
1346
1347#if _LIBCPP_STD_VER > 14
1348template <class _Tp>
1349_LIBCPP_INLINE_VAR constexpr size_t tuple_size_v = tuple_size<_Tp>::value;
1350
1351#define _LIBCPP_NOEXCEPT_RETURN(...) noexcept(noexcept(__VA_ARGS__)) { return __VA_ARGS__; }
1352
1353template <class _Fn, class _Tuple, size_t ..._Id>
1354inline _LIBCPP_INLINE_VISIBILITY
1355constexpr decltype(auto) __apply_tuple_impl(_Fn && __f, _Tuple && __t,
1356                                            __tuple_indices<_Id...>)
1357_LIBCPP_NOEXCEPT_RETURN(
1358    _VSTD::__invoke_constexpr(
1359        _VSTD::forward<_Fn>(__f),
1360        _VSTD::get<_Id>(_VSTD::forward<_Tuple>(__t))...)
1361)
1362
1363template <class _Fn, class _Tuple>
1364inline _LIBCPP_INLINE_VISIBILITY
1365constexpr decltype(auto) apply(_Fn && __f, _Tuple && __t)
1366_LIBCPP_NOEXCEPT_RETURN(
1367    _VSTD::__apply_tuple_impl(
1368        _VSTD::forward<_Fn>(__f), _VSTD::forward<_Tuple>(__t),
1369        typename __make_tuple_indices<tuple_size_v<remove_reference_t<_Tuple>>>::type{})
1370)
1371
1372template <class _Tp, class _Tuple, size_t... _Idx>
1373inline _LIBCPP_INLINE_VISIBILITY
1374constexpr _Tp __make_from_tuple_impl(_Tuple&& __t, __tuple_indices<_Idx...>)
1375_LIBCPP_NOEXCEPT_RETURN(
1376    _Tp(_VSTD::get<_Idx>(_VSTD::forward<_Tuple>(__t))...)
1377)
1378
1379template <class _Tp, class _Tuple>
1380inline _LIBCPP_INLINE_VISIBILITY
1381constexpr _Tp make_from_tuple(_Tuple&& __t)
1382_LIBCPP_NOEXCEPT_RETURN(
1383    _VSTD::__make_from_tuple_impl<_Tp>(_VSTD::forward<_Tuple>(__t),
1384        typename __make_tuple_indices<tuple_size_v<remove_reference_t<_Tuple>>>::type{})
1385)
1386
1387#undef _LIBCPP_NOEXCEPT_RETURN
1388
1389#endif // _LIBCPP_STD_VER > 14
1390
1391#endif // !defined(_LIBCPP_CXX03_LANG)
1392
1393_LIBCPP_END_NAMESPACE_STD
1394
1395#endif  // _LIBCPP_TUPLE
1396