tuple revision 360784 
1// -*- C++ -*-
2//===--------------------------- tuple ------------------------------------===//
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_TUPLE
11#define _LIBCPP_TUPLE
12
13/*
14    tuple synopsis
15
16namespace std
17{
18
19template <class... T>
20class tuple {
21public:
22    explicit(see-below) constexpr tuple();
23    explicit(see-below) tuple(const T&...);  // constexpr in C++14
24    template <class... U>
25        explicit(see-below) tuple(U&&...);  // constexpr in C++14
26    tuple(const tuple&) = default;
27    tuple(tuple&&) = default;
28    template <class... U>
29        explicit(see-below) tuple(const tuple<U...>&);  // constexpr in C++14
30    template <class... U>
31        explicit(see-below) tuple(tuple<U...>&&);  // constexpr in C++14
32    template <class U1, class U2>
33        explicit(see-below) tuple(const pair<U1, U2>&); // iff sizeof...(T) == 2 // constexpr in C++14
34    template <class U1, class U2>
35        explicit(see-below) tuple(pair<U1, U2>&&); // iff sizeof...(T) == 2  // constexpr in C++14
36
37    // allocator-extended constructors
38    template <class Alloc>
39        tuple(allocator_arg_t, const Alloc& a);
40    template <class Alloc>
41        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, const T&...);
42    template <class Alloc, class... U>
43        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, U&&...);
44    template <class Alloc>
45        tuple(allocator_arg_t, const Alloc& a, const tuple&);
46    template <class Alloc>
47        tuple(allocator_arg_t, const Alloc& a, tuple&&);
48    template <class Alloc, class... U>
49        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, const tuple<U...>&);
50    template <class Alloc, class... U>
51        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, tuple<U...>&&);
52    template <class Alloc, class U1, class U2>
53        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, const pair<U1, U2>&);
54    template <class Alloc, class U1, class U2>
55        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, pair<U1, U2>&&);
56
57    tuple& operator=(const tuple&);
58    tuple&
59        operator=(tuple&&) noexcept(AND(is_nothrow_move_assignable<T>::value ...));
60    template <class... U>
61        tuple& operator=(const tuple<U...>&);
62    template <class... U>
63        tuple& operator=(tuple<U...>&&);
64    template <class U1, class U2>
65        tuple& operator=(const pair<U1, U2>&); // iff sizeof...(T) == 2
66    template <class U1, class U2>
67        tuple& operator=(pair<U1, U2>&&); // iff sizeof...(T) == 2
68
69    void swap(tuple&) noexcept(AND(swap(declval<T&>(), declval<T&>())...));
70};
71
72template <class ...T>
73tuple(T...) -> tuple<T...>;                                         // since C++17
74template <class T1, class T2>
75tuple(pair<T1, T2>) -> tuple<T1, T2>;                               // since C++17
76template <class Alloc, class ...T>
77tuple(allocator_arg_t, Alloc, T...) -> tuple<T...>;                 // since C++17
78template <class Alloc, class T1, class T2>
79tuple(allocator_arg_t, Alloc, pair<T1, T2>) -> tuple<T1, T2>;       // since C++17
80template <class Alloc, class ...T>
81tuple(allocator_arg_t, Alloc, tuple<T...>) -> tuple<T...>;          // since C++17
82
83inline constexpr unspecified ignore;
84
85template <class... T> tuple<V...>  make_tuple(T&&...); // constexpr in C++14
86template <class... T> tuple<ATypes...> forward_as_tuple(T&&...) noexcept; // constexpr in C++14
87template <class... T> tuple<T&...> tie(T&...) noexcept; // constexpr in C++14
88template <class... Tuples> tuple<CTypes...> tuple_cat(Tuples&&... tpls); // constexpr in C++14
89
90// [tuple.apply], calling a function with a tuple of arguments:
91template <class F, class Tuple>
92  constexpr decltype(auto) apply(F&& f, Tuple&& t); // C++17
93template <class T, class Tuple>
94  constexpr T make_from_tuple(Tuple&& t); // C++17
95
96// 20.4.1.4, tuple helper classes:
97template <class T> struct tuple_size; // undefined
98template <class... T> struct tuple_size<tuple<T...>>;
99template <class T>
100 inline constexpr size_t tuple_size_v = tuple_size<T>::value; // C++17
101template <size_t I, class T> struct tuple_element; // undefined
102template <size_t I, class... T> struct tuple_element<I, tuple<T...>>;
103template <size_t I, class T>
104  using tuple_element_t = typename tuple_element <I, T>::type; // C++14
105
106// 20.4.1.5, element access:
107template <size_t I, class... T>
108    typename tuple_element<I, tuple<T...>>::type&
109    get(tuple<T...>&) noexcept; // constexpr in C++14
110template <size_t I, class... T>
111    const typename tuple_element<I, tuple<T...>>::type&
112    get(const tuple<T...>&) noexcept; // constexpr in C++14
113template <size_t I, class... T>
114    typename tuple_element<I, tuple<T...>>::type&&
115    get(tuple<T...>&&) noexcept; // constexpr in C++14
116template <size_t I, class... T>
117    const typename tuple_element<I, tuple<T...>>::type&&
118    get(const tuple<T...>&&) noexcept; // constexpr in C++14
119
120template <class T1, class... T>
121    constexpr T1& get(tuple<T...>&) noexcept;  // C++14
122template <class T1, class... T>
123    constexpr const T1& get(const tuple<T...>&) noexcept;   // C++14
124template <class T1, class... T>
125    constexpr T1&& get(tuple<T...>&&) noexcept;   // C++14
126template <class T1, class... T>
127    constexpr const T1&& get(const tuple<T...>&&) noexcept;   // C++14
128
129// 20.4.1.6, relational operators:
130template<class... T, class... U> bool operator==(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14
131template<class... T, class... U> bool operator<(const tuple<T...>&, const tuple<U...>&);  // constexpr in C++14
132template<class... T, class... U> bool operator!=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14
133template<class... T, class... U> bool operator>(const tuple<T...>&, const tuple<U...>&);  // constexpr in C++14
134template<class... T, class... U> bool operator<=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14
135template<class... T, class... U> bool operator>=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14
136
137template <class... Types, class Alloc>
138  struct uses_allocator<tuple<Types...>, Alloc>;
139
140template <class... Types>
141  void
142  swap(tuple<Types...>& x, tuple<Types...>& y) noexcept(noexcept(x.swap(y)));
143
144}  // std
145
146*/
147
148#include <__config>
149#include <__tuple>
150#include <cstddef>
151#include <type_traits>
152#include <__functional_base>
153#include <utility>
154#include <version>
155
156#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
157#pragma GCC system_header
158#endif
159
160_LIBCPP_BEGIN_NAMESPACE_STD
161
162#ifndef _LIBCPP_CXX03_LANG
163
164
165// __tuple_leaf
166
167template <size_t _Ip, class _Hp,
168          bool=is_empty<_Hp>::value && !__libcpp_is_final<_Hp>::value
169         >
170class __tuple_leaf;
171
172template <size_t _Ip, class _Hp, bool _Ep>
173inline _LIBCPP_INLINE_VISIBILITY
174void swap(__tuple_leaf<_Ip, _Hp, _Ep>& __x, __tuple_leaf<_Ip, _Hp, _Ep>& __y)
175    _NOEXCEPT_(__is_nothrow_swappable<_Hp>::value)
176{
177    swap(__x.get(), __y.get());
178}
179
180template <size_t _Ip, class _Hp, bool>
181class __tuple_leaf
182{
183    _Hp __value_;
184
185    template <class _Tp>
186    static constexpr bool __can_bind_reference() {
187#if __has_keyword(__reference_binds_to_temporary)
188      return !__reference_binds_to_temporary(_Hp, _Tp);
189#else
190      return true;
191#endif
192    }
193
194    __tuple_leaf& operator=(const __tuple_leaf&);
195public:
196    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR __tuple_leaf()
197             _NOEXCEPT_(is_nothrow_default_constructible<_Hp>::value) : __value_()
198       {static_assert(!is_reference<_Hp>::value,
199              "Attempted to default construct a reference element in a tuple");}
200
201    template <class _Alloc>
202        _LIBCPP_INLINE_VISIBILITY
203        __tuple_leaf(integral_constant<int, 0>, const _Alloc&)
204            : __value_()
205        {static_assert(!is_reference<_Hp>::value,
206              "Attempted to default construct a reference element in a tuple");}
207
208    template <class _Alloc>
209        _LIBCPP_INLINE_VISIBILITY
210        __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a)
211            : __value_(allocator_arg_t(), __a)
212        {static_assert(!is_reference<_Hp>::value,
213              "Attempted to default construct a reference element in a tuple");}
214
215    template <class _Alloc>
216        _LIBCPP_INLINE_VISIBILITY
217        __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a)
218            : __value_(__a)
219        {static_assert(!is_reference<_Hp>::value,
220              "Attempted to default construct a reference element in a tuple");}
221
222    template <class _Tp,
223              class = _EnableIf<
224                  _And<
225                      _IsNotSame<__uncvref_t<_Tp>, __tuple_leaf>,
226                      is_constructible<_Hp, _Tp>
227                    >::value
228                >
229            >
230        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
231        explicit __tuple_leaf(_Tp&& __t) _NOEXCEPT_((is_nothrow_constructible<_Hp, _Tp>::value))
232            : __value_(_VSTD::forward<_Tp>(__t))
233        {static_assert(__can_bind_reference<_Tp&&>(),
234       "Attempted construction of reference element binds to a temporary whose lifetime has ended");}
235
236    template <class _Tp, class _Alloc>
237        _LIBCPP_INLINE_VISIBILITY
238        explicit __tuple_leaf(integral_constant<int, 0>, const _Alloc&, _Tp&& __t)
239            : __value_(_VSTD::forward<_Tp>(__t))
240        {static_assert(__can_bind_reference<_Tp&&>(),
241       "Attempted construction of reference element binds to a temporary whose lifetime has ended");}
242
243    template <class _Tp, class _Alloc>
244        _LIBCPP_INLINE_VISIBILITY
245        explicit __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a, _Tp&& __t)
246            : __value_(allocator_arg_t(), __a, _VSTD::forward<_Tp>(__t))
247        {static_assert(!is_reference<_Hp>::value,
248            "Attempted to uses-allocator construct a reference element in a tuple");}
249
250    template <class _Tp, class _Alloc>
251        _LIBCPP_INLINE_VISIBILITY
252        explicit __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a, _Tp&& __t)
253            : __value_(_VSTD::forward<_Tp>(__t), __a)
254        {static_assert(!is_reference<_Hp>::value,
255           "Attempted to uses-allocator construct a reference element in a tuple");}
256
257    __tuple_leaf(const __tuple_leaf& __t) = default;
258    __tuple_leaf(__tuple_leaf&& __t) = default;
259
260    template <class _Tp>
261        _LIBCPP_INLINE_VISIBILITY
262        __tuple_leaf&
263        operator=(_Tp&& __t) _NOEXCEPT_((is_nothrow_assignable<_Hp&, _Tp>::value))
264        {
265            __value_ = _VSTD::forward<_Tp>(__t);
266            return *this;
267        }
268
269    _LIBCPP_INLINE_VISIBILITY
270    int swap(__tuple_leaf& __t) _NOEXCEPT_(__is_nothrow_swappable<__tuple_leaf>::value)
271    {
272        _VSTD::swap(*this, __t);
273        return 0;
274    }
275
276    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11       _Hp& get()       _NOEXCEPT {return __value_;}
277    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 const _Hp& get() const _NOEXCEPT {return __value_;}
278};
279
280template <size_t _Ip, class _Hp>
281class __tuple_leaf<_Ip, _Hp, true>
282    : private _Hp
283{
284
285    __tuple_leaf& operator=(const __tuple_leaf&);
286public:
287    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR __tuple_leaf()
288             _NOEXCEPT_(is_nothrow_default_constructible<_Hp>::value) {}
289
290    template <class _Alloc>
291        _LIBCPP_INLINE_VISIBILITY
292        __tuple_leaf(integral_constant<int, 0>, const _Alloc&) {}
293
294    template <class _Alloc>
295        _LIBCPP_INLINE_VISIBILITY
296        __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a)
297            : _Hp(allocator_arg_t(), __a) {}
298
299    template <class _Alloc>
300        _LIBCPP_INLINE_VISIBILITY
301        __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a)
302            : _Hp(__a) {}
303
304    template <class _Tp,
305              class = _EnableIf<
306                  _And<
307                    _IsNotSame<__uncvref_t<_Tp>, __tuple_leaf>,
308                    is_constructible<_Hp, _Tp>
309                  >::value
310                >
311            >
312        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
313        explicit __tuple_leaf(_Tp&& __t) _NOEXCEPT_((is_nothrow_constructible<_Hp, _Tp>::value))
314            : _Hp(_VSTD::forward<_Tp>(__t)) {}
315
316    template <class _Tp, class _Alloc>
317        _LIBCPP_INLINE_VISIBILITY
318        explicit __tuple_leaf(integral_constant<int, 0>, const _Alloc&, _Tp&& __t)
319            : _Hp(_VSTD::forward<_Tp>(__t)) {}
320
321    template <class _Tp, class _Alloc>
322        _LIBCPP_INLINE_VISIBILITY
323        explicit __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a, _Tp&& __t)
324            : _Hp(allocator_arg_t(), __a, _VSTD::forward<_Tp>(__t)) {}
325
326    template <class _Tp, class _Alloc>
327        _LIBCPP_INLINE_VISIBILITY
328        explicit __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a, _Tp&& __t)
329            : _Hp(_VSTD::forward<_Tp>(__t), __a) {}
330
331    __tuple_leaf(__tuple_leaf const &) = default;
332    __tuple_leaf(__tuple_leaf &&) = default;
333
334    template <class _Tp>
335        _LIBCPP_INLINE_VISIBILITY
336        __tuple_leaf&
337        operator=(_Tp&& __t) _NOEXCEPT_((is_nothrow_assignable<_Hp&, _Tp>::value))
338        {
339            _Hp::operator=(_VSTD::forward<_Tp>(__t));
340            return *this;
341        }
342
343    _LIBCPP_INLINE_VISIBILITY
344    int
345    swap(__tuple_leaf& __t) _NOEXCEPT_(__is_nothrow_swappable<__tuple_leaf>::value)
346    {
347        _VSTD::swap(*this, __t);
348        return 0;
349    }
350
351    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11       _Hp& get()       _NOEXCEPT {return static_cast<_Hp&>(*this);}
352    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 const _Hp& get() const _NOEXCEPT {return static_cast<const _Hp&>(*this);}
353};
354
355template <class ..._Tp>
356_LIBCPP_INLINE_VISIBILITY
357void __swallow(_Tp&&...) _NOEXCEPT {}
358
359template <class _Tp>
360struct __all_default_constructible;
361
362template <class ..._Tp>
363struct __all_default_constructible<__tuple_types<_Tp...>>
364    : __all<is_default_constructible<_Tp>::value...>
365{ };
366
367// __tuple_impl
368
369template<class _Indx, class ..._Tp> struct __tuple_impl;
370
371template<size_t ..._Indx, class ..._Tp>
372struct _LIBCPP_DECLSPEC_EMPTY_BASES __tuple_impl<__tuple_indices<_Indx...>, _Tp...>
373    : public __tuple_leaf<_Indx, _Tp>...
374{
375    _LIBCPP_INLINE_VISIBILITY
376    _LIBCPP_CONSTEXPR __tuple_impl()
377        _NOEXCEPT_(__all<is_nothrow_default_constructible<_Tp>::value...>::value) {}
378
379    template <size_t ..._Uf, class ..._Tf,
380              size_t ..._Ul, class ..._Tl, class ..._Up>
381        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
382        explicit
383        __tuple_impl(__tuple_indices<_Uf...>, __tuple_types<_Tf...>,
384                     __tuple_indices<_Ul...>, __tuple_types<_Tl...>,
385                     _Up&&... __u)
386                     _NOEXCEPT_((__all<is_nothrow_constructible<_Tf, _Up>::value...>::value &&
387                                 __all<is_nothrow_default_constructible<_Tl>::value...>::value)) :
388            __tuple_leaf<_Uf, _Tf>(_VSTD::forward<_Up>(__u))...,
389            __tuple_leaf<_Ul, _Tl>()...
390            {}
391
392    template <class _Alloc, size_t ..._Uf, class ..._Tf,
393              size_t ..._Ul, class ..._Tl, class ..._Up>
394        _LIBCPP_INLINE_VISIBILITY
395        explicit
396        __tuple_impl(allocator_arg_t, const _Alloc& __a,
397                     __tuple_indices<_Uf...>, __tuple_types<_Tf...>,
398                     __tuple_indices<_Ul...>, __tuple_types<_Tl...>,
399                     _Up&&... __u) :
400            __tuple_leaf<_Uf, _Tf>(__uses_alloc_ctor<_Tf, _Alloc, _Up>(), __a,
401            _VSTD::forward<_Up>(__u))...,
402            __tuple_leaf<_Ul, _Tl>(__uses_alloc_ctor<_Tl, _Alloc>(), __a)...
403            {}
404
405    template <class _Tuple,
406              class = typename enable_if
407                      <
408                         __tuple_constructible<_Tuple, tuple<_Tp...> >::value
409                      >::type
410             >
411        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
412        __tuple_impl(_Tuple&& __t) _NOEXCEPT_((__all<is_nothrow_constructible<_Tp, typename tuple_element<_Indx,
413                                       typename __make_tuple_types<_Tuple>::type>::type>::value...>::value))
414            : __tuple_leaf<_Indx, _Tp>(_VSTD::forward<typename tuple_element<_Indx,
415                                       typename __make_tuple_types<_Tuple>::type>::type>(_VSTD::get<_Indx>(__t)))...
416            {}
417
418    template <class _Alloc, class _Tuple,
419              class = typename enable_if
420                      <
421                         __tuple_constructible<_Tuple, tuple<_Tp...> >::value
422                      >::type
423             >
424        _LIBCPP_INLINE_VISIBILITY
425        __tuple_impl(allocator_arg_t, const _Alloc& __a, _Tuple&& __t)
426            : __tuple_leaf<_Indx, _Tp>(__uses_alloc_ctor<_Tp, _Alloc, typename tuple_element<_Indx,
427                                       typename __make_tuple_types<_Tuple>::type>::type>(), __a,
428                                       _VSTD::forward<typename tuple_element<_Indx,
429                                       typename __make_tuple_types<_Tuple>::type>::type>(_VSTD::get<_Indx>(__t)))...
430            {}
431
432    template <class _Tuple>
433        _LIBCPP_INLINE_VISIBILITY
434        typename enable_if
435        <
436            __tuple_assignable<_Tuple, tuple<_Tp...> >::value,
437            __tuple_impl&
438        >::type
439        operator=(_Tuple&& __t) _NOEXCEPT_((__all<is_nothrow_assignable<_Tp&, typename tuple_element<_Indx,
440                                       typename __make_tuple_types<_Tuple>::type>::type>::value...>::value))
441        {
442            __swallow(__tuple_leaf<_Indx, _Tp>::operator=(_VSTD::forward<typename tuple_element<_Indx,
443                                       typename __make_tuple_types<_Tuple>::type>::type>(_VSTD::get<_Indx>(__t)))...);
444            return *this;
445        }
446
447    __tuple_impl(const __tuple_impl&) = default;
448    __tuple_impl(__tuple_impl&&) = default;
449
450    _LIBCPP_INLINE_VISIBILITY
451    __tuple_impl&
452    operator=(const __tuple_impl& __t) _NOEXCEPT_((__all<is_nothrow_copy_assignable<_Tp>::value...>::value))
453    {
454        __swallow(__tuple_leaf<_Indx, _Tp>::operator=(static_cast<const __tuple_leaf<_Indx, _Tp>&>(__t).get())...);
455        return *this;
456    }
457
458    _LIBCPP_INLINE_VISIBILITY
459    __tuple_impl&
460    operator=(__tuple_impl&& __t) _NOEXCEPT_((__all<is_nothrow_move_assignable<_Tp>::value...>::value))
461    {
462        __swallow(__tuple_leaf<_Indx, _Tp>::operator=(_VSTD::forward<_Tp>(static_cast<__tuple_leaf<_Indx, _Tp>&>(__t).get()))...);
463        return *this;
464    }
465
466    _LIBCPP_INLINE_VISIBILITY
467    void swap(__tuple_impl& __t)
468        _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
469    {
470        __swallow(__tuple_leaf<_Indx, _Tp>::swap(static_cast<__tuple_leaf<_Indx, _Tp>&>(__t))...);
471    }
472};
473
474
475
476template <class ..._Tp>
477class _LIBCPP_TEMPLATE_VIS tuple
478{
479    typedef __tuple_impl<typename __make_tuple_indices<sizeof...(_Tp)>::type, _Tp...> _BaseT;
480
481    _BaseT __base_;
482
483#if defined(_LIBCPP_ENABLE_TUPLE_IMPLICIT_REDUCED_ARITY_EXTENSION)
484    static constexpr bool _EnableImplicitReducedArityExtension = true;
485#else
486    static constexpr bool _EnableImplicitReducedArityExtension = false;
487#endif
488
489    template <class ..._Args>
490    struct _PackExpandsToThisTuple : false_type {};
491
492    template <class _Arg>
493    struct _PackExpandsToThisTuple<_Arg>
494        : is_same<typename __uncvref<_Arg>::type, tuple> {};
495
496    template <bool _MaybeEnable, class _Dummy = void>
497    struct _CheckArgsConstructor : __check_tuple_constructor_fail {};
498
499    template <class _Dummy>
500    struct _CheckArgsConstructor<true, _Dummy>
501    {
502        template <int&...>
503        static constexpr bool __enable_implicit_default() {
504           return __all<__is_implicitly_default_constructible<_Tp>::value... >::value;
505        }
506
507        template <int&...>
508        static constexpr bool __enable_explicit_default() {
509            return
510                __all<is_default_constructible<_Tp>::value...>::value &&
511                !__enable_implicit_default< >();
512        }
513
514
515        template <class ..._Args>
516        static constexpr bool __enable_explicit() {
517            return
518                __tuple_constructible<
519                    tuple<_Args...>,
520                    typename __make_tuple_types<tuple,
521                             sizeof...(_Args) < sizeof...(_Tp) ?
522                                 sizeof...(_Args) :
523                                 sizeof...(_Tp)>::type
524                >::value &&
525                !__tuple_convertible<
526                    tuple<_Args...>,
527                    typename __make_tuple_types<tuple,
528                             sizeof...(_Args) < sizeof...(_Tp) ?
529                                 sizeof...(_Args) :
530                                 sizeof...(_Tp)>::type
531                >::value &&
532                __all_default_constructible<
533                    typename __make_tuple_types<tuple, sizeof...(_Tp),
534                             sizeof...(_Args) < sizeof...(_Tp) ?
535                                 sizeof...(_Args) :
536                                 sizeof...(_Tp)>::type
537                >::value;
538        }
539
540        template <class ..._Args>
541        static constexpr bool __enable_implicit() {
542            return
543               __tuple_constructible<
544                    tuple<_Args...>,
545                    typename __make_tuple_types<tuple,
546                             sizeof...(_Args) < sizeof...(_Tp) ?
547                                 sizeof...(_Args) :
548                                 sizeof...(_Tp)>::type
549                >::value &&
550                __tuple_convertible<
551                    tuple<_Args...>,
552                    typename __make_tuple_types<tuple,
553                             sizeof...(_Args) < sizeof...(_Tp) ?
554                                 sizeof...(_Args) :
555                                 sizeof...(_Tp)>::type
556                >::value &&
557                __all_default_constructible<
558                    typename __make_tuple_types<tuple, sizeof...(_Tp),
559                             sizeof...(_Args) < sizeof...(_Tp) ?
560                                 sizeof...(_Args) :
561                                 sizeof...(_Tp)>::type
562                >::value;
563        }
564    };
565
566    template <bool _MaybeEnable,
567              bool = sizeof...(_Tp) == 1,
568              class _Dummy = void>
569    struct _CheckTupleLikeConstructor : __check_tuple_constructor_fail {};
570
571    template <class _Dummy>
572    struct _CheckTupleLikeConstructor<true, false, _Dummy>
573    {
574        template <class _Tuple>
575        static constexpr bool __enable_implicit() {
576            return __tuple_constructible<_Tuple, tuple>::value
577                && __tuple_convertible<_Tuple, tuple>::value;
578        }
579
580        template <class _Tuple>
581        static constexpr bool __enable_explicit() {
582            return __tuple_constructible<_Tuple, tuple>::value
583               && !__tuple_convertible<_Tuple, tuple>::value;
584        }
585    };
586
587    template <class _Dummy>
588    struct _CheckTupleLikeConstructor<true, true, _Dummy>
589    {
590        // This trait is used to disable the tuple-like constructor when
591        // the UTypes... constructor should be selected instead.
592        // See LWG issue #2549.
593        template <class _Tuple>
594        using _PreferTupleLikeConstructor = _Or<
595            // Don't attempt the two checks below if the tuple we are given
596            // has the same type as this tuple.
597            _IsSame<__uncvref_t<_Tuple>, tuple>,
598            _Lazy<_And,
599                _Not<is_constructible<_Tp..., _Tuple>>,
600                _Not<is_convertible<_Tuple, _Tp...>>
601            >
602        >;
603
604        template <class _Tuple>
605        static constexpr bool __enable_implicit() {
606            return _And<
607                __tuple_constructible<_Tuple, tuple>,
608                __tuple_convertible<_Tuple, tuple>,
609                _PreferTupleLikeConstructor<_Tuple>
610            >::value;
611        }
612
613        template <class _Tuple>
614        static constexpr bool __enable_explicit() {
615            return _And<
616                __tuple_constructible<_Tuple, tuple>,
617                _PreferTupleLikeConstructor<_Tuple>,
618                _Not<__tuple_convertible<_Tuple, tuple>>
619            >::value;
620        }
621    };
622
623    template <class _Tuple, bool _DisableIfLValue>
624    using _EnableImplicitTupleLikeConstructor = _EnableIf<
625                         _CheckTupleLikeConstructor<
626                             __tuple_like_with_size<_Tuple, sizeof...(_Tp)>::value
627                             && !_PackExpandsToThisTuple<_Tuple>::value
628                             && (!is_lvalue_reference<_Tuple>::value || !_DisableIfLValue)
629                         >::template __enable_implicit<_Tuple>(),
630                         bool
631                      >;
632
633    template <class _Tuple, bool _DisableIfLValue>
634    using _EnableExplicitTupleLikeConstructor = _EnableIf<
635                         _CheckTupleLikeConstructor<
636                             __tuple_like_with_size<_Tuple, sizeof...(_Tp)>::value
637                             && !_PackExpandsToThisTuple<_Tuple>::value
638                             && (!is_lvalue_reference<_Tuple>::value || !_DisableIfLValue)
639                         >::template __enable_explicit<_Tuple>(),
640                         bool
641                      >;
642    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
643        typename tuple_element<_Jp, tuple<_Up...> >::type& get(tuple<_Up...>&) _NOEXCEPT;
644    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
645        const typename tuple_element<_Jp, tuple<_Up...> >::type& get(const tuple<_Up...>&) _NOEXCEPT;
646    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
647        typename tuple_element<_Jp, tuple<_Up...> >::type&& get(tuple<_Up...>&&) _NOEXCEPT;
648    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
649        const typename tuple_element<_Jp, tuple<_Up...> >::type&& get(const tuple<_Up...>&&) _NOEXCEPT;
650public:
651
652    template <bool _Dummy = true, _EnableIf<
653        _CheckArgsConstructor<_Dummy>::__enable_implicit_default()
654    , void*> = nullptr>
655    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
656    tuple()
657        _NOEXCEPT_(__all<is_nothrow_default_constructible<_Tp>::value...>::value) {}
658
659    template <bool _Dummy = true, _EnableIf<
660        _CheckArgsConstructor<_Dummy>::__enable_explicit_default()
661    , void*> = nullptr>
662    explicit _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
663    tuple()
664        _NOEXCEPT_(__all<is_nothrow_default_constructible<_Tp>::value...>::value) {}
665
666    tuple(tuple const&) = default;
667    tuple(tuple&&) = default;
668
669    template <class _AllocArgT, class _Alloc, _EnableIf<
670             _CheckArgsConstructor<_IsSame<allocator_arg_t, _AllocArgT>::value >::__enable_implicit_default()
671      , void*> = nullptr
672    >
673    _LIBCPP_INLINE_VISIBILITY
674    tuple(_AllocArgT, _Alloc const& __a)
675      : __base_(allocator_arg_t(), __a,
676                    __tuple_indices<>(), __tuple_types<>(),
677                    typename __make_tuple_indices<sizeof...(_Tp), 0>::type(),
678                    __tuple_types<_Tp...>()) {}
679
680    template <class _AllocArgT, class _Alloc, _EnableIf<
681             _CheckArgsConstructor<_IsSame<allocator_arg_t, _AllocArgT>::value>::__enable_explicit_default()
682      , void*> = nullptr
683    >
684    explicit _LIBCPP_INLINE_VISIBILITY
685    tuple(_AllocArgT, _Alloc const& __a)
686      : __base_(allocator_arg_t(), __a,
687                    __tuple_indices<>(), __tuple_types<>(),
688                    typename __make_tuple_indices<sizeof...(_Tp), 0>::type(),
689                    __tuple_types<_Tp...>()) {}
690
691    template <bool _Dummy = true,
692              typename enable_if
693                      <
694                         _CheckArgsConstructor<
695                            _Dummy
696                         >::template __enable_implicit<_Tp const&...>(),
697                         bool
698                      >::type = false
699        >
700    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
701    tuple(const _Tp& ... __t) _NOEXCEPT_((__all<is_nothrow_copy_constructible<_Tp>::value...>::value))
702        : __base_(typename __make_tuple_indices<sizeof...(_Tp)>::type(),
703                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
704                typename __make_tuple_indices<0>::type(),
705                typename __make_tuple_types<tuple, 0>::type(),
706                __t...
707               ) {}
708
709    template <bool _Dummy = true,
710              typename enable_if
711                      <
712                         _CheckArgsConstructor<
713                            _Dummy
714                         >::template __enable_explicit<_Tp const&...>(),
715                         bool
716                      >::type = false
717        >
718    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
719    explicit tuple(const _Tp& ... __t) _NOEXCEPT_((__all<is_nothrow_copy_constructible<_Tp>::value...>::value))
720        : __base_(typename __make_tuple_indices<sizeof...(_Tp)>::type(),
721                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
722                typename __make_tuple_indices<0>::type(),
723                typename __make_tuple_types<tuple, 0>::type(),
724                __t...
725               ) {}
726
727    template <class _Alloc, bool _Dummy = true,
728              typename enable_if
729                      <
730                         _CheckArgsConstructor<
731                            _Dummy
732                         >::template __enable_implicit<_Tp const&...>(),
733                         bool
734                      >::type = false
735        >
736      _LIBCPP_INLINE_VISIBILITY
737      tuple(allocator_arg_t, const _Alloc& __a, const _Tp& ... __t)
738        : __base_(allocator_arg_t(), __a,
739                typename __make_tuple_indices<sizeof...(_Tp)>::type(),
740                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
741                typename __make_tuple_indices<0>::type(),
742                typename __make_tuple_types<tuple, 0>::type(),
743                __t...
744               ) {}
745
746    template <class _Alloc, bool _Dummy = true,
747              typename enable_if
748                      <
749                         _CheckArgsConstructor<
750                            _Dummy
751                         >::template __enable_explicit<_Tp const&...>(),
752                         bool
753                      >::type = false
754        >
755      _LIBCPP_INLINE_VISIBILITY
756      explicit
757      tuple(allocator_arg_t, const _Alloc& __a, const _Tp& ... __t)
758        : __base_(allocator_arg_t(), __a,
759                typename __make_tuple_indices<sizeof...(_Tp)>::type(),
760                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
761                typename __make_tuple_indices<0>::type(),
762                typename __make_tuple_types<tuple, 0>::type(),
763                __t...
764               ) {}
765
766    template <class ..._Up,
767              bool _PackIsTuple = _PackExpandsToThisTuple<_Up...>::value,
768              typename enable_if
769                      <
770                         _CheckArgsConstructor<
771                             sizeof...(_Up) == sizeof...(_Tp)
772                             && !_PackIsTuple
773                         >::template __enable_implicit<_Up...>() ||
774                        _CheckArgsConstructor<
775                            _EnableImplicitReducedArityExtension
776                            && sizeof...(_Up) < sizeof...(_Tp)
777                            && !_PackIsTuple
778                         >::template __enable_implicit<_Up...>(),
779                         bool
780                      >::type = false
781             >
782        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
783        tuple(_Up&&... __u)
784            _NOEXCEPT_((
785                is_nothrow_constructible<_BaseT,
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                    _Up...
791                >::value
792            ))
793            : __base_(typename __make_tuple_indices<sizeof...(_Up)>::type(),
794                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
795                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
796                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
797                    _VSTD::forward<_Up>(__u)...) {}
798
799    template <class ..._Up,
800              typename enable_if
801                      <
802                         _CheckArgsConstructor<
803                             sizeof...(_Up) <= sizeof...(_Tp)
804                             && !_PackExpandsToThisTuple<_Up...>::value
805                         >::template __enable_explicit<_Up...>() ||
806                         _CheckArgsConstructor<
807                            !_EnableImplicitReducedArityExtension
808                            && sizeof...(_Up) < sizeof...(_Tp)
809                            && !_PackExpandsToThisTuple<_Up...>::value
810                         >::template __enable_implicit<_Up...>(),
811                         bool
812                      >::type = false
813             >
814        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
815        explicit
816        tuple(_Up&&... __u)
817            _NOEXCEPT_((
818                is_nothrow_constructible<_BaseT,
819                    typename __make_tuple_indices<sizeof...(_Up)>::type,
820                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type,
821                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type,
822                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type,
823                    _Up...
824                >::value
825            ))
826            : __base_(typename __make_tuple_indices<sizeof...(_Up)>::type(),
827                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
828                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
829                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
830                    _VSTD::forward<_Up>(__u)...) {}
831
832    template <class _Alloc, class ..._Up,
833              typename enable_if
834                      <
835                         _CheckArgsConstructor<
836                             sizeof...(_Up) == sizeof...(_Tp) &&
837                             !_PackExpandsToThisTuple<_Up...>::value
838                         >::template __enable_implicit<_Up...>(),
839                         bool
840                      >::type = false
841             >
842        _LIBCPP_INLINE_VISIBILITY
843        tuple(allocator_arg_t, const _Alloc& __a, _Up&&... __u)
844            : __base_(allocator_arg_t(), __a,
845                    typename __make_tuple_indices<sizeof...(_Up)>::type(),
846                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
847                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
848                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
849                    _VSTD::forward<_Up>(__u)...) {}
850
851    template <class _Alloc, class ..._Up,
852              typename enable_if
853                      <
854                         _CheckArgsConstructor<
855                             sizeof...(_Up) == sizeof...(_Tp) &&
856                             !_PackExpandsToThisTuple<_Up...>::value
857                         >::template __enable_explicit<_Up...>(),
858                         bool
859                      >::type = false
860             >
861        _LIBCPP_INLINE_VISIBILITY
862        explicit
863        tuple(allocator_arg_t, const _Alloc& __a, _Up&&... __u)
864            : __base_(allocator_arg_t(), __a,
865                    typename __make_tuple_indices<sizeof...(_Up)>::type(),
866                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
867                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
868                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
869                    _VSTD::forward<_Up>(__u)...) {}
870
871    template <class _Tuple, _EnableImplicitTupleLikeConstructor<_Tuple, true> = false>
872        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
873        tuple(_Tuple&& __t) _NOEXCEPT_((is_nothrow_constructible<_BaseT, _Tuple>::value))
874            : __base_(_VSTD::forward<_Tuple>(__t)) {}
875
876    template <class _Tuple, _EnableImplicitTupleLikeConstructor<const _Tuple&, false> = false>
877        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
878        tuple(const _Tuple& __t) _NOEXCEPT_((is_nothrow_constructible<_BaseT, const _Tuple&>::value))
879            : __base_(__t) {}
880    template <class _Tuple, _EnableExplicitTupleLikeConstructor<_Tuple, true> = false>
881        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
882        explicit
883        tuple(_Tuple&& __t) _NOEXCEPT_((is_nothrow_constructible<_BaseT, _Tuple>::value))
884            : __base_(_VSTD::forward<_Tuple>(__t)) {}
885
886    template <class _Tuple, _EnableExplicitTupleLikeConstructor<const _Tuple&, false> = false>
887        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
888        explicit
889        tuple(const _Tuple& __t) _NOEXCEPT_((is_nothrow_constructible<_BaseT, const _Tuple&>::value))
890            : __base_(__t) {}
891
892    template <class _Alloc, class _Tuple,
893              typename enable_if
894                      <
895                         _CheckTupleLikeConstructor<
896                             __tuple_like_with_size<_Tuple, sizeof...(_Tp)>::value
897                         >::template __enable_implicit<_Tuple>(),
898                         bool
899                      >::type = false
900             >
901        _LIBCPP_INLINE_VISIBILITY
902        tuple(allocator_arg_t, const _Alloc& __a, _Tuple&& __t)
903            : __base_(allocator_arg_t(), __a, _VSTD::forward<_Tuple>(__t)) {}
904
905    template <class _Alloc, class _Tuple,
906              typename enable_if
907                      <
908                         _CheckTupleLikeConstructor<
909                             __tuple_like_with_size<_Tuple, sizeof...(_Tp)>::value
910                         >::template __enable_explicit<_Tuple>(),
911                         bool
912                      >::type = false
913             >
914        _LIBCPP_INLINE_VISIBILITY
915        explicit
916        tuple(allocator_arg_t, const _Alloc& __a, _Tuple&& __t)
917            : __base_(allocator_arg_t(), __a, _VSTD::forward<_Tuple>(__t)) {}
918
919    using _CanCopyAssign = __all<is_copy_assignable<_Tp>::value...>;
920    using _CanMoveAssign = __all<is_move_assignable<_Tp>::value...>;
921
922    _LIBCPP_INLINE_VISIBILITY
923    tuple& operator=(typename conditional<_CanCopyAssign::value, tuple, __nat>::type const& __t)
924        _NOEXCEPT_((__all<is_nothrow_copy_assignable<_Tp>::value...>::value))
925    {
926        __base_.operator=(__t.__base_);
927        return *this;
928    }
929
930    _LIBCPP_INLINE_VISIBILITY
931    tuple& operator=(typename conditional<_CanMoveAssign::value, tuple, __nat>::type&& __t)
932        _NOEXCEPT_((__all<is_nothrow_move_assignable<_Tp>::value...>::value))
933    {
934        __base_.operator=(static_cast<_BaseT&&>(__t.__base_));
935        return *this;
936    }
937
938    template <class _Tuple,
939              class = typename enable_if
940                      <
941                         __tuple_assignable<_Tuple, tuple>::value
942                      >::type
943             >
944        _LIBCPP_INLINE_VISIBILITY
945        tuple&
946        operator=(_Tuple&& __t) _NOEXCEPT_((is_nothrow_assignable<_BaseT&, _Tuple>::value))
947        {
948            __base_.operator=(_VSTD::forward<_Tuple>(__t));
949            return *this;
950        }
951
952    _LIBCPP_INLINE_VISIBILITY
953    void swap(tuple& __t) _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
954        {__base_.swap(__t.__base_);}
955};
956
957template <>
958class _LIBCPP_TEMPLATE_VIS tuple<>
959{
960public:
961    _LIBCPP_INLINE_VISIBILITY
962    _LIBCPP_CONSTEXPR tuple() _NOEXCEPT = default;
963    template <class _Alloc>
964    _LIBCPP_INLINE_VISIBILITY
965        tuple(allocator_arg_t, const _Alloc&) _NOEXCEPT {}
966    template <class _Alloc>
967    _LIBCPP_INLINE_VISIBILITY
968        tuple(allocator_arg_t, const _Alloc&, const tuple&) _NOEXCEPT {}
969    template <class _Up>
970    _LIBCPP_INLINE_VISIBILITY
971        tuple(array<_Up, 0>) _NOEXCEPT {}
972    template <class _Alloc, class _Up>
973    _LIBCPP_INLINE_VISIBILITY
974        tuple(allocator_arg_t, const _Alloc&, array<_Up, 0>) _NOEXCEPT {}
975    _LIBCPP_INLINE_VISIBILITY
976    void swap(tuple&) _NOEXCEPT {}
977};
978
979#ifndef _LIBCPP_HAS_NO_DEDUCTION_GUIDES
980template <class ..._Tp>
981tuple(_Tp...) -> tuple<_Tp...>;
982template <class _Tp1, class _Tp2>
983tuple(pair<_Tp1, _Tp2>) -> tuple<_Tp1, _Tp2>;
984template <class _Alloc, class ..._Tp>
985tuple(allocator_arg_t, _Alloc, _Tp...) -> tuple<_Tp...>;
986template <class _Alloc, class _Tp1, class _Tp2>
987tuple(allocator_arg_t, _Alloc, pair<_Tp1, _Tp2>) -> tuple<_Tp1, _Tp2>;
988template <class _Alloc, class ..._Tp>
989tuple(allocator_arg_t, _Alloc, tuple<_Tp...>) -> tuple<_Tp...>;
990#endif
991
992template <class ..._Tp>
993inline _LIBCPP_INLINE_VISIBILITY
994typename enable_if
995<
996    __all<__is_swappable<_Tp>::value...>::value,
997    void
998>::type
999swap(tuple<_Tp...>& __t, tuple<_Tp...>& __u)
1000                 _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
1001    {__t.swap(__u);}
1002
1003// get
1004
1005template <size_t _Ip, class ..._Tp>
1006inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1007typename tuple_element<_Ip, tuple<_Tp...> >::type&
1008get(tuple<_Tp...>& __t) _NOEXCEPT
1009{
1010    typedef _LIBCPP_NODEBUG_TYPE typename tuple_element<_Ip, tuple<_Tp...> >::type type;
1011    return static_cast<__tuple_leaf<_Ip, type>&>(__t.__base_).get();
1012}
1013
1014template <size_t _Ip, class ..._Tp>
1015inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1016const typename tuple_element<_Ip, tuple<_Tp...> >::type&
1017get(const tuple<_Tp...>& __t) _NOEXCEPT
1018{
1019    typedef _LIBCPP_NODEBUG_TYPE typename tuple_element<_Ip, tuple<_Tp...> >::type type;
1020    return static_cast<const __tuple_leaf<_Ip, type>&>(__t.__base_).get();
1021}
1022
1023template <size_t _Ip, class ..._Tp>
1024inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1025typename tuple_element<_Ip, tuple<_Tp...> >::type&&
1026get(tuple<_Tp...>&& __t) _NOEXCEPT
1027{
1028    typedef _LIBCPP_NODEBUG_TYPE typename tuple_element<_Ip, tuple<_Tp...> >::type type;
1029    return static_cast<type&&>(
1030             static_cast<__tuple_leaf<_Ip, type>&&>(__t.__base_).get());
1031}
1032
1033template <size_t _Ip, class ..._Tp>
1034inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1035const typename tuple_element<_Ip, tuple<_Tp...> >::type&&
1036get(const tuple<_Tp...>&& __t) _NOEXCEPT
1037{
1038    typedef _LIBCPP_NODEBUG_TYPE typename tuple_element<_Ip, tuple<_Tp...> >::type type;
1039    return static_cast<const type&&>(
1040             static_cast<const __tuple_leaf<_Ip, type>&&>(__t.__base_).get());
1041}
1042
1043#if _LIBCPP_STD_VER > 11
1044
1045namespace __find_detail {
1046
1047static constexpr size_t __not_found = -1;
1048static constexpr size_t __ambiguous = __not_found - 1;
1049
1050inline _LIBCPP_INLINE_VISIBILITY
1051constexpr size_t __find_idx_return(size_t __curr_i, size_t __res, bool __matches) {
1052    return !__matches ? __res :
1053        (__res == __not_found ? __curr_i : __ambiguous);
1054}
1055
1056template <size_t _Nx>
1057inline _LIBCPP_INLINE_VISIBILITY
1058constexpr size_t __find_idx(size_t __i, const bool (&__matches)[_Nx]) {
1059  return __i == _Nx ? __not_found :
1060      __find_idx_return(__i, __find_idx(__i + 1, __matches), __matches[__i]);
1061}
1062
1063template <class _T1, class ..._Args>
1064struct __find_exactly_one_checked {
1065    static constexpr bool __matches[sizeof...(_Args)] = {is_same<_T1, _Args>::value...};
1066    static constexpr size_t value = __find_detail::__find_idx(0, __matches);
1067    static_assert(value != __not_found, "type not found in type list" );
1068    static_assert(value != __ambiguous, "type occurs more than once in type list");
1069};
1070
1071template <class _T1>
1072struct __find_exactly_one_checked<_T1> {
1073    static_assert(!is_same<_T1, _T1>::value, "type not in empty type list");
1074};
1075
1076} // namespace __find_detail;
1077
1078template <typename _T1, typename... _Args>
1079struct __find_exactly_one_t
1080    : public __find_detail::__find_exactly_one_checked<_T1, _Args...> {
1081};
1082
1083template <class _T1, class... _Args>
1084inline _LIBCPP_INLINE_VISIBILITY
1085constexpr _T1& get(tuple<_Args...>& __tup) noexcept
1086{
1087    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(__tup);
1088}
1089
1090template <class _T1, class... _Args>
1091inline _LIBCPP_INLINE_VISIBILITY
1092constexpr _T1 const& get(tuple<_Args...> const& __tup) noexcept
1093{
1094    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(__tup);
1095}
1096
1097template <class _T1, class... _Args>
1098inline _LIBCPP_INLINE_VISIBILITY
1099constexpr _T1&& get(tuple<_Args...>&& __tup) noexcept
1100{
1101    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(_VSTD::move(__tup));
1102}
1103
1104template <class _T1, class... _Args>
1105inline _LIBCPP_INLINE_VISIBILITY
1106constexpr _T1 const&& get(tuple<_Args...> const&& __tup) noexcept
1107{
1108    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(_VSTD::move(__tup));
1109}
1110
1111#endif
1112
1113// tie
1114
1115template <class ..._Tp>
1116inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1117tuple<_Tp&...>
1118tie(_Tp&... __t) _NOEXCEPT
1119{
1120    return tuple<_Tp&...>(__t...);
1121}
1122
1123template <class _Up>
1124struct __ignore_t
1125{
1126    template <class _Tp>
1127    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1128    const __ignore_t& operator=(_Tp&&) const {return *this;}
1129};
1130
1131namespace {
1132  _LIBCPP_INLINE_VAR constexpr __ignore_t<unsigned char> ignore = __ignore_t<unsigned char>();
1133}
1134
1135template <class... _Tp>
1136inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1137tuple<typename __unwrap_ref_decay<_Tp>::type...>
1138make_tuple(_Tp&&... __t)
1139{
1140    return tuple<typename __unwrap_ref_decay<_Tp>::type...>(_VSTD::forward<_Tp>(__t)...);
1141}
1142
1143template <class... _Tp>
1144inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1145tuple<_Tp&&...>
1146forward_as_tuple(_Tp&&... __t) _NOEXCEPT
1147{
1148    return tuple<_Tp&&...>(_VSTD::forward<_Tp>(__t)...);
1149}
1150
1151template <size_t _Ip>
1152struct __tuple_equal
1153{
1154    template <class _Tp, class _Up>
1155    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1156    bool operator()(const _Tp& __x, const _Up& __y)
1157    {
1158        return __tuple_equal<_Ip - 1>()(__x, __y) && _VSTD::get<_Ip-1>(__x) == _VSTD::get<_Ip-1>(__y);
1159    }
1160};
1161
1162template <>
1163struct __tuple_equal<0>
1164{
1165    template <class _Tp, class _Up>
1166    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1167    bool operator()(const _Tp&, const _Up&)
1168    {
1169        return true;
1170    }
1171};
1172
1173template <class ..._Tp, class ..._Up>
1174inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1175bool
1176operator==(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1177{
1178    static_assert (sizeof...(_Tp) == sizeof...(_Up), "Can't compare tuples of different sizes");
1179    return __tuple_equal<sizeof...(_Tp)>()(__x, __y);
1180}
1181
1182template <class ..._Tp, class ..._Up>
1183inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1184bool
1185operator!=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1186{
1187    return !(__x == __y);
1188}
1189
1190template <size_t _Ip>
1191struct __tuple_less
1192{
1193    template <class _Tp, class _Up>
1194    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1195    bool operator()(const _Tp& __x, const _Up& __y)
1196    {
1197        const size_t __idx = tuple_size<_Tp>::value - _Ip;
1198        if (_VSTD::get<__idx>(__x) < _VSTD::get<__idx>(__y))
1199            return true;
1200        if (_VSTD::get<__idx>(__y) < _VSTD::get<__idx>(__x))
1201            return false;
1202        return __tuple_less<_Ip-1>()(__x, __y);
1203    }
1204};
1205
1206template <>
1207struct __tuple_less<0>
1208{
1209    template <class _Tp, class _Up>
1210    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1211    bool operator()(const _Tp&, const _Up&)
1212    {
1213        return false;
1214    }
1215};
1216
1217template <class ..._Tp, class ..._Up>
1218inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1219bool
1220operator<(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1221{
1222    static_assert (sizeof...(_Tp) == sizeof...(_Up), "Can't compare tuples of different sizes");
1223    return __tuple_less<sizeof...(_Tp)>()(__x, __y);
1224}
1225
1226template <class ..._Tp, class ..._Up>
1227inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1228bool
1229operator>(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1230{
1231    return __y < __x;
1232}
1233
1234template <class ..._Tp, class ..._Up>
1235inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1236bool
1237operator>=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1238{
1239    return !(__x < __y);
1240}
1241
1242template <class ..._Tp, class ..._Up>
1243inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1244bool
1245operator<=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1246{
1247    return !(__y < __x);
1248}
1249
1250// tuple_cat
1251
1252template <class _Tp, class _Up> struct __tuple_cat_type;
1253
1254template <class ..._Ttypes, class ..._Utypes>
1255struct __tuple_cat_type<tuple<_Ttypes...>, __tuple_types<_Utypes...> >
1256{
1257    typedef _LIBCPP_NODEBUG_TYPE tuple<_Ttypes..., _Utypes...> type;
1258};
1259
1260template <class _ResultTuple, bool _Is_Tuple0TupleLike, class ..._Tuples>
1261struct __tuple_cat_return_1
1262{
1263};
1264
1265template <class ..._Types, class _Tuple0>
1266struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0>
1267{
1268    typedef _LIBCPP_NODEBUG_TYPE typename __tuple_cat_type<tuple<_Types...>,
1269            typename __make_tuple_types<typename __uncvref<_Tuple0>::type>::type>::type
1270                                                                           type;
1271};
1272
1273template <class ..._Types, class _Tuple0, class _Tuple1, class ..._Tuples>
1274struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0, _Tuple1, _Tuples...>
1275    : public __tuple_cat_return_1<
1276                 typename __tuple_cat_type<
1277                     tuple<_Types...>,
1278                     typename __make_tuple_types<typename __uncvref<_Tuple0>::type>::type
1279                 >::type,
1280                 __tuple_like<typename remove_reference<_Tuple1>::type>::value,
1281                 _Tuple1, _Tuples...>
1282{
1283};
1284
1285template <class ..._Tuples> struct __tuple_cat_return;
1286
1287template <class _Tuple0, class ..._Tuples>
1288struct __tuple_cat_return<_Tuple0, _Tuples...>
1289    : public __tuple_cat_return_1<tuple<>,
1290         __tuple_like<typename remove_reference<_Tuple0>::type>::value, _Tuple0,
1291                                                                     _Tuples...>
1292{
1293};
1294
1295template <>
1296struct __tuple_cat_return<>
1297{
1298    typedef _LIBCPP_NODEBUG_TYPE tuple<> type;
1299};
1300
1301inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1302tuple<>
1303tuple_cat()
1304{
1305    return tuple<>();
1306}
1307
1308template <class _Rp, class _Indices, class _Tuple0, class ..._Tuples>
1309struct __tuple_cat_return_ref_imp;
1310
1311template <class ..._Types, size_t ..._I0, class _Tuple0>
1312struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>, _Tuple0>
1313{
1314    typedef _LIBCPP_NODEBUG_TYPE typename remove_reference<_Tuple0>::type _T0;
1315    typedef tuple<_Types..., typename __apply_cv<_Tuple0,
1316                          typename tuple_element<_I0, _T0>::type>::type&&...> type;
1317};
1318
1319template <class ..._Types, size_t ..._I0, class _Tuple0, class _Tuple1, class ..._Tuples>
1320struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>,
1321                                  _Tuple0, _Tuple1, _Tuples...>
1322    : public __tuple_cat_return_ref_imp<
1323         tuple<_Types..., typename __apply_cv<_Tuple0,
1324               typename tuple_element<_I0,
1325                  typename remove_reference<_Tuple0>::type>::type>::type&&...>,
1326         typename __make_tuple_indices<tuple_size<typename
1327                                 remove_reference<_Tuple1>::type>::value>::type,
1328         _Tuple1, _Tuples...>
1329{
1330};
1331
1332template <class _Tuple0, class ..._Tuples>
1333struct __tuple_cat_return_ref
1334    : public __tuple_cat_return_ref_imp<tuple<>,
1335               typename __make_tuple_indices<
1336                        tuple_size<typename remove_reference<_Tuple0>::type>::value
1337               >::type, _Tuple0, _Tuples...>
1338{
1339};
1340
1341template <class _Types, class _I0, class _J0>
1342struct __tuple_cat;
1343
1344template <class ..._Types, size_t ..._I0, size_t ..._J0>
1345struct __tuple_cat<tuple<_Types...>, __tuple_indices<_I0...>, __tuple_indices<_J0...> >
1346{
1347    template <class _Tuple0>
1348    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1349    typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&>::type
1350    operator()(tuple<_Types...> __t, _Tuple0&& __t0)
1351    {
1352        return _VSTD::forward_as_tuple(
1353            _VSTD::forward<_Types>(_VSTD::get<_I0>(__t))...,
1354            _VSTD::get<_J0>(_VSTD::forward<_Tuple0>(__t0))...);
1355    }
1356
1357    template <class _Tuple0, class _Tuple1, class ..._Tuples>
1358    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1359    typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&, _Tuple1&&, _Tuples&&...>::type
1360    operator()(tuple<_Types...> __t, _Tuple0&& __t0, _Tuple1&& __t1, _Tuples&& ...__tpls)
1361    {
1362        typedef _LIBCPP_NODEBUG_TYPE typename remove_reference<_Tuple0>::type _T0;
1363        typedef _LIBCPP_NODEBUG_TYPE typename remove_reference<_Tuple1>::type _T1;
1364        return __tuple_cat<
1365            tuple<_Types...,
1366                  typename __apply_cv<_Tuple0, typename tuple_element<
1367                                                   _J0, _T0>::type>::type&&...>,
1368            typename __make_tuple_indices<sizeof...(_Types) +
1369                                          tuple_size<_T0>::value>::type,
1370            typename __make_tuple_indices<tuple_size<_T1>::value>::type>()(
1371            _VSTD::forward_as_tuple(
1372                _VSTD::forward<_Types>(_VSTD::get<_I0>(__t))...,
1373                _VSTD::get<_J0>(_VSTD::forward<_Tuple0>(__t0))...),
1374            _VSTD::forward<_Tuple1>(__t1), _VSTD::forward<_Tuples>(__tpls)...);
1375    }
1376};
1377
1378template <class _Tuple0, class... _Tuples>
1379inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1380typename __tuple_cat_return<_Tuple0, _Tuples...>::type
1381tuple_cat(_Tuple0&& __t0, _Tuples&&... __tpls)
1382{
1383    typedef _LIBCPP_NODEBUG_TYPE typename remove_reference<_Tuple0>::type _T0;
1384    return __tuple_cat<tuple<>, __tuple_indices<>,
1385                  typename __make_tuple_indices<tuple_size<_T0>::value>::type>()
1386                  (tuple<>(), _VSTD::forward<_Tuple0>(__t0),
1387                                            _VSTD::forward<_Tuples>(__tpls)...);
1388}
1389
1390template <class ..._Tp, class _Alloc>
1391struct _LIBCPP_TEMPLATE_VIS uses_allocator<tuple<_Tp...>, _Alloc>
1392    : true_type {};
1393
1394template <class _T1, class _T2>
1395template <class... _Args1, class... _Args2, size_t ..._I1, size_t ..._I2>
1396inline _LIBCPP_INLINE_VISIBILITY
1397pair<_T1, _T2>::pair(piecewise_construct_t,
1398                     tuple<_Args1...>& __first_args, tuple<_Args2...>& __second_args,
1399                     __tuple_indices<_I1...>, __tuple_indices<_I2...>)
1400    :  first(_VSTD::forward<_Args1>(_VSTD::get<_I1>( __first_args))...),
1401      second(_VSTD::forward<_Args2>(_VSTD::get<_I2>(__second_args))...)
1402{
1403}
1404
1405#if _LIBCPP_STD_VER > 14
1406template <class _Tp>
1407_LIBCPP_INLINE_VAR constexpr size_t tuple_size_v = tuple_size<_Tp>::value;
1408
1409#define _LIBCPP_NOEXCEPT_RETURN(...) noexcept(noexcept(__VA_ARGS__)) { return __VA_ARGS__; }
1410
1411template <class _Fn, class _Tuple, size_t ..._Id>
1412inline _LIBCPP_INLINE_VISIBILITY
1413constexpr decltype(auto) __apply_tuple_impl(_Fn && __f, _Tuple && __t,
1414                                            __tuple_indices<_Id...>)
1415_LIBCPP_NOEXCEPT_RETURN(
1416    _VSTD::__invoke_constexpr(
1417        _VSTD::forward<_Fn>(__f),
1418        _VSTD::get<_Id>(_VSTD::forward<_Tuple>(__t))...)
1419)
1420
1421template <class _Fn, class _Tuple>
1422inline _LIBCPP_INLINE_VISIBILITY
1423constexpr decltype(auto) apply(_Fn && __f, _Tuple && __t)
1424_LIBCPP_NOEXCEPT_RETURN(
1425    _VSTD::__apply_tuple_impl(
1426        _VSTD::forward<_Fn>(__f), _VSTD::forward<_Tuple>(__t),
1427        typename __make_tuple_indices<tuple_size_v<remove_reference_t<_Tuple>>>::type{})
1428)
1429
1430template <class _Tp, class _Tuple, size_t... _Idx>
1431inline _LIBCPP_INLINE_VISIBILITY
1432constexpr _Tp __make_from_tuple_impl(_Tuple&& __t, __tuple_indices<_Idx...>)
1433_LIBCPP_NOEXCEPT_RETURN(
1434    _Tp(_VSTD::get<_Idx>(_VSTD::forward<_Tuple>(__t))...)
1435)
1436
1437template <class _Tp, class _Tuple>
1438inline _LIBCPP_INLINE_VISIBILITY
1439constexpr _Tp make_from_tuple(_Tuple&& __t)
1440_LIBCPP_NOEXCEPT_RETURN(
1441    _VSTD::__make_from_tuple_impl<_Tp>(_VSTD::forward<_Tuple>(__t),
1442        typename __make_tuple_indices<tuple_size_v<remove_reference_t<_Tuple>>>::type{})
1443)
1444
1445#undef _LIBCPP_NOEXCEPT_RETURN
1446
1447#endif // _LIBCPP_STD_VER > 14
1448
1449#endif // !defined(_LIBCPP_CXX03_LANG)
1450
1451_LIBCPP_END_NAMESPACE_STD
1452
1453#endif  // _LIBCPP_TUPLE
1454