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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>&&); //iffsizeof...(T) == 2
69
70    void swap(tuple&) noexcept(AND(swap(declval<T&>(), declval<T&>())...));
71};
72
73const 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> class tuple_size; // undefined
88template <class... T> class tuple_size<tuple<T...>>;
89template <class T>
90 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
145#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
146#pragma GCC system_header
147#endif
148
149_LIBCPP_BEGIN_NAMESPACE_STD
150
151#ifndef _LIBCPP_HAS_NO_VARIADICS
152
153
154// __tuple_leaf
155
156template <size_t _Ip, class _Hp,
157          bool=is_empty<_Hp>::value && !__libcpp_is_final<_Hp>::value
158         >
159class __tuple_leaf;
160
161template <size_t _Ip, class _Hp, bool _Ep>
162inline _LIBCPP_INLINE_VISIBILITY
163void swap(__tuple_leaf<_Ip, _Hp, _Ep>& __x, __tuple_leaf<_Ip, _Hp, _Ep>& __y)
164    _NOEXCEPT_(__is_nothrow_swappable<_Hp>::value)
165{
166    swap(__x.get(), __y.get());
167}
168
169template <size_t _Ip, class _Hp, bool>
170class __tuple_leaf
171{
172    _Hp value;
173
174    template <class _Tp>
175    static constexpr bool __can_bind_reference() {
176        using _RawTp = typename remove_reference<_Tp>::type;
177        using _RawHp = typename remove_reference<_Hp>::type;
178        using _CheckLValueArg = integral_constant<bool,
179            is_lvalue_reference<_Tp>::value
180        ||  is_same<_RawTp, reference_wrapper<_RawHp>>::value
181        ||  is_same<_RawTp, reference_wrapper<typename remove_const<_RawHp>::type>>::value
182        >;
183        return  !is_reference<_Hp>::value
184            || (is_lvalue_reference<_Hp>::value && _CheckLValueArg::value)
185            || (is_rvalue_reference<_Hp>::value && !is_lvalue_reference<_Tp>::value);
186    }
187
188    __tuple_leaf& operator=(const __tuple_leaf&);
189public:
190    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR __tuple_leaf()
191             _NOEXCEPT_(is_nothrow_default_constructible<_Hp>::value) : value()
192       {static_assert(!is_reference<_Hp>::value,
193              "Attempted to default construct a reference element in a tuple");}
194
195    template <class _Alloc>
196        _LIBCPP_INLINE_VISIBILITY
197        __tuple_leaf(integral_constant<int, 0>, const _Alloc&)
198            : value()
199        {static_assert(!is_reference<_Hp>::value,
200              "Attempted to default construct a reference element in a tuple");}
201
202    template <class _Alloc>
203        _LIBCPP_INLINE_VISIBILITY
204        __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a)
205            : value(allocator_arg_t(), __a)
206        {static_assert(!is_reference<_Hp>::value,
207              "Attempted to default construct a reference element in a tuple");}
208
209    template <class _Alloc>
210        _LIBCPP_INLINE_VISIBILITY
211        __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a)
212            : value(__a)
213        {static_assert(!is_reference<_Hp>::value,
214              "Attempted to default construct a reference element in a tuple");}
215
216    template <class _Tp,
217              class = typename enable_if<
218                  __lazy_and<
219                      __lazy_not<is_same<typename decay<_Tp>::type, __tuple_leaf>>
220                    , is_constructible<_Hp, _Tp>
221                    >::value
222                >::type
223            >
224        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
225        explicit __tuple_leaf(_Tp&& __t) _NOEXCEPT_((is_nothrow_constructible<_Hp, _Tp>::value))
226            : value(_VSTD::forward<_Tp>(__t))
227        {static_assert(__can_bind_reference<_Tp>(),
228       "Attempted to construct a reference element in a tuple with an rvalue");}
229
230    template <class _Tp, class _Alloc>
231        _LIBCPP_INLINE_VISIBILITY
232        explicit __tuple_leaf(integral_constant<int, 0>, const _Alloc&, _Tp&& __t)
233            : value(_VSTD::forward<_Tp>(__t))
234        {static_assert(__can_bind_reference<_Tp>(),
235       "Attempted to construct a reference element in a tuple with an rvalue");}
236
237    template <class _Tp, class _Alloc>
238        _LIBCPP_INLINE_VISIBILITY
239        explicit __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a, _Tp&& __t)
240            : value(allocator_arg_t(), __a, _VSTD::forward<_Tp>(__t))
241        {static_assert(!is_reference<_Hp>::value,
242            "Attempted to uses-allocator construct a reference element in a tuple");}
243
244    template <class _Tp, class _Alloc>
245        _LIBCPP_INLINE_VISIBILITY
246        explicit __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a, _Tp&& __t)
247            : value(_VSTD::forward<_Tp>(__t), __a)
248        {static_assert(!is_reference<_Hp>::value,
249           "Attempted to uses-allocator construct a reference element in a tuple");}
250
251    __tuple_leaf(const __tuple_leaf& __t) = default;
252    __tuple_leaf(__tuple_leaf&& __t) = default;
253
254    template <class _Tp>
255        _LIBCPP_INLINE_VISIBILITY
256        __tuple_leaf&
257        operator=(_Tp&& __t) _NOEXCEPT_((is_nothrow_assignable<_Hp&, _Tp>::value))
258        {
259            value = _VSTD::forward<_Tp>(__t);
260            return *this;
261        }
262
263    _LIBCPP_INLINE_VISIBILITY
264    int swap(__tuple_leaf& __t) _NOEXCEPT_(__is_nothrow_swappable<__tuple_leaf>::value)
265    {
266        _VSTD::swap(*this, __t);
267        return 0;
268    }
269
270    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11       _Hp& get()       _NOEXCEPT {return value;}
271    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 const _Hp& get() const _NOEXCEPT {return value;}
272};
273
274template <size_t _Ip, class _Hp>
275class __tuple_leaf<_Ip, _Hp, true>
276    : private _Hp
277{
278
279    __tuple_leaf& operator=(const __tuple_leaf&);
280public:
281    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR __tuple_leaf()
282             _NOEXCEPT_(is_nothrow_default_constructible<_Hp>::value) {}
283
284    template <class _Alloc>
285        _LIBCPP_INLINE_VISIBILITY
286        __tuple_leaf(integral_constant<int, 0>, const _Alloc&) {}
287
288    template <class _Alloc>
289        _LIBCPP_INLINE_VISIBILITY
290        __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a)
291            : _Hp(allocator_arg_t(), __a) {}
292
293    template <class _Alloc>
294        _LIBCPP_INLINE_VISIBILITY
295        __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a)
296            : _Hp(__a) {}
297
298    template <class _Tp,
299              class = typename enable_if<
300                  __lazy_and<
301                        __lazy_not<is_same<typename decay<_Tp>::type, __tuple_leaf>>
302                      , is_constructible<_Hp, _Tp>
303                    >::value
304                >::type
305            >
306        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
307        explicit __tuple_leaf(_Tp&& __t) _NOEXCEPT_((is_nothrow_constructible<_Hp, _Tp>::value))
308            : _Hp(_VSTD::forward<_Tp>(__t)) {}
309
310    template <class _Tp, class _Alloc>
311        _LIBCPP_INLINE_VISIBILITY
312        explicit __tuple_leaf(integral_constant<int, 0>, const _Alloc&, _Tp&& __t)
313            : _Hp(_VSTD::forward<_Tp>(__t)) {}
314
315    template <class _Tp, class _Alloc>
316        _LIBCPP_INLINE_VISIBILITY
317        explicit __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a, _Tp&& __t)
318            : _Hp(allocator_arg_t(), __a, _VSTD::forward<_Tp>(__t)) {}
319
320    template <class _Tp, class _Alloc>
321        _LIBCPP_INLINE_VISIBILITY
322        explicit __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a, _Tp&& __t)
323            : _Hp(_VSTD::forward<_Tp>(__t), __a) {}
324
325    __tuple_leaf(__tuple_leaf const &) = default;
326    __tuple_leaf(__tuple_leaf &&) = default;
327
328    template <class _Tp>
329        _LIBCPP_INLINE_VISIBILITY
330        __tuple_leaf&
331        operator=(_Tp&& __t) _NOEXCEPT_((is_nothrow_assignable<_Hp&, _Tp>::value))
332        {
333            _Hp::operator=(_VSTD::forward<_Tp>(__t));
334            return *this;
335        }
336
337    _LIBCPP_INLINE_VISIBILITY
338    int
339    swap(__tuple_leaf& __t) _NOEXCEPT_(__is_nothrow_swappable<__tuple_leaf>::value)
340    {
341        _VSTD::swap(*this, __t);
342        return 0;
343    }
344
345    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11       _Hp& get()       _NOEXCEPT {return static_cast<_Hp&>(*this);}
346    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11 const _Hp& get() const _NOEXCEPT {return static_cast<const _Hp&>(*this);}
347};
348
349template <class ..._Tp>
350_LIBCPP_INLINE_VISIBILITY
351void __swallow(_Tp&&...) _NOEXCEPT {}
352
353template <class ..._Tp>
354struct __lazy_all : __all<_Tp::value...> {};
355
356template <class _Tp>
357struct __all_default_constructible;
358
359template <class ..._Tp>
360struct __all_default_constructible<__tuple_types<_Tp...>>
361    : __all<is_default_constructible<_Tp>::value...>
362{ };
363
364// __tuple_impl
365
366template<class _Indx, class ..._Tp> struct __tuple_impl;
367
368template<size_t ..._Indx, class ..._Tp>
369struct _LIBCPP_DECLSPEC_EMPTY_BASES __tuple_impl<__tuple_indices<_Indx...>, _Tp...>
370    : public __tuple_leaf<_Indx, _Tp>...
371{
372    _LIBCPP_INLINE_VISIBILITY
373    _LIBCPP_CONSTEXPR __tuple_impl()
374        _NOEXCEPT_(__all<is_nothrow_default_constructible<_Tp>::value...>::value) {}
375
376    template <size_t ..._Uf, class ..._Tf,
377              size_t ..._Ul, class ..._Tl, class ..._Up>
378        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
379        explicit
380        __tuple_impl(__tuple_indices<_Uf...>, __tuple_types<_Tf...>,
381                     __tuple_indices<_Ul...>, __tuple_types<_Tl...>,
382                     _Up&&... __u)
383                     _NOEXCEPT_((__all<is_nothrow_constructible<_Tf, _Up>::value...>::value &&
384                                 __all<is_nothrow_default_constructible<_Tl>::value...>::value)) :
385            __tuple_leaf<_Uf, _Tf>(_VSTD::forward<_Up>(__u))...,
386            __tuple_leaf<_Ul, _Tl>()...
387            {}
388
389    template <class _Alloc, size_t ..._Uf, class ..._Tf,
390              size_t ..._Ul, class ..._Tl, class ..._Up>
391        _LIBCPP_INLINE_VISIBILITY
392        explicit
393        __tuple_impl(allocator_arg_t, const _Alloc& __a,
394                     __tuple_indices<_Uf...>, __tuple_types<_Tf...>,
395                     __tuple_indices<_Ul...>, __tuple_types<_Tl...>,
396                     _Up&&... __u) :
397            __tuple_leaf<_Uf, _Tf>(__uses_alloc_ctor<_Tf, _Alloc, _Up>(), __a,
398            _VSTD::forward<_Up>(__u))...,
399            __tuple_leaf<_Ul, _Tl>(__uses_alloc_ctor<_Tl, _Alloc>(), __a)...
400            {}
401
402    template <class _Tuple,
403              class = typename enable_if
404                      <
405                         __tuple_constructible<_Tuple, tuple<_Tp...> >::value
406                      >::type
407             >
408        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
409        __tuple_impl(_Tuple&& __t) _NOEXCEPT_((__all<is_nothrow_constructible<_Tp, typename tuple_element<_Indx,
410                                       typename __make_tuple_types<_Tuple>::type>::type>::value...>::value))
411            : __tuple_leaf<_Indx, _Tp>(_VSTD::forward<typename tuple_element<_Indx,
412                                       typename __make_tuple_types<_Tuple>::type>::type>(_VSTD::get<_Indx>(__t)))...
413            {}
414
415    template <class _Alloc, class _Tuple,
416              class = typename enable_if
417                      <
418                         __tuple_constructible<_Tuple, tuple<_Tp...> >::value
419                      >::type
420             >
421        _LIBCPP_INLINE_VISIBILITY
422        __tuple_impl(allocator_arg_t, const _Alloc& __a, _Tuple&& __t)
423            : __tuple_leaf<_Indx, _Tp>(__uses_alloc_ctor<_Tp, _Alloc, typename tuple_element<_Indx,
424                                       typename __make_tuple_types<_Tuple>::type>::type>(), __a,
425                                       _VSTD::forward<typename tuple_element<_Indx,
426                                       typename __make_tuple_types<_Tuple>::type>::type>(_VSTD::get<_Indx>(__t)))...
427            {}
428
429    template <class _Tuple>
430        _LIBCPP_INLINE_VISIBILITY
431        typename enable_if
432        <
433            __tuple_assignable<_Tuple, tuple<_Tp...> >::value,
434            __tuple_impl&
435        >::type
436        operator=(_Tuple&& __t) _NOEXCEPT_((__all<is_nothrow_assignable<_Tp&, typename tuple_element<_Indx,
437                                       typename __make_tuple_types<_Tuple>::type>::type>::value...>::value))
438        {
439            __swallow(__tuple_leaf<_Indx, _Tp>::operator=(_VSTD::forward<typename tuple_element<_Indx,
440                                       typename __make_tuple_types<_Tuple>::type>::type>(_VSTD::get<_Indx>(__t)))...);
441            return *this;
442        }
443
444    __tuple_impl(const __tuple_impl&) = default;
445    __tuple_impl(__tuple_impl&&) = default;
446
447    _LIBCPP_INLINE_VISIBILITY
448    __tuple_impl&
449    operator=(const __tuple_impl& __t) _NOEXCEPT_((__all<is_nothrow_copy_assignable<_Tp>::value...>::value))
450    {
451        __swallow(__tuple_leaf<_Indx, _Tp>::operator=(static_cast<const __tuple_leaf<_Indx, _Tp>&>(__t).get())...);
452        return *this;
453    }
454
455    _LIBCPP_INLINE_VISIBILITY
456    __tuple_impl&
457    operator=(__tuple_impl&& __t) _NOEXCEPT_((__all<is_nothrow_move_assignable<_Tp>::value...>::value))
458    {
459        __swallow(__tuple_leaf<_Indx, _Tp>::operator=(_VSTD::forward<_Tp>(static_cast<__tuple_leaf<_Indx, _Tp>&>(__t).get()))...);
460        return *this;
461    }
462
463    _LIBCPP_INLINE_VISIBILITY
464    void swap(__tuple_impl& __t)
465        _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
466    {
467        __swallow(__tuple_leaf<_Indx, _Tp>::swap(static_cast<__tuple_leaf<_Indx, _Tp>&>(__t))...);
468    }
469};
470
471
472
473template <class ..._Tp>
474class _LIBCPP_TEMPLATE_VIS tuple
475{
476    typedef __tuple_impl<typename __make_tuple_indices<sizeof...(_Tp)>::type, _Tp...> base;
477
478    base base_;
479
480#if defined(_LIBCPP_ENABLE_TUPLE_IMPLICIT_REDUCED_ARITY_EXTENSION)
481    static constexpr bool _EnableImplicitReducedArityExtension = true;
482#else
483    static constexpr bool _EnableImplicitReducedArityExtension = false;
484#endif
485
486    template <class ..._Args>
487    struct _PackExpandsToThisTuple : false_type {};
488
489    template <class _Arg>
490    struct _PackExpandsToThisTuple<_Arg>
491        : is_same<typename __uncvref<_Arg>::type, tuple> {};
492
493    template <bool _MaybeEnable, class _Dummy = void>
494    struct _CheckArgsConstructor : __check_tuple_constructor_fail {};
495
496    template <class _Dummy>
497    struct _CheckArgsConstructor<true, _Dummy>
498    {
499        template <class ..._Args>
500        static constexpr bool __enable_default() {
501            return __all<is_default_constructible<_Args>::value...>::value;
502        }
503
504        template <class ..._Args>
505        static constexpr bool __enable_explicit() {
506            return
507                __tuple_constructible<
508                    tuple<_Args...>,
509                    typename __make_tuple_types<tuple,
510                             sizeof...(_Args) < sizeof...(_Tp) ?
511                                 sizeof...(_Args) :
512                                 sizeof...(_Tp)>::type
513                >::value &&
514                !__tuple_convertible<
515                    tuple<_Args...>,
516                    typename __make_tuple_types<tuple,
517                             sizeof...(_Args) < sizeof...(_Tp) ?
518                                 sizeof...(_Args) :
519                                 sizeof...(_Tp)>::type
520                >::value &&
521                __all_default_constructible<
522                    typename __make_tuple_types<tuple, sizeof...(_Tp),
523                             sizeof...(_Args) < sizeof...(_Tp) ?
524                                 sizeof...(_Args) :
525                                 sizeof...(_Tp)>::type
526                >::value;
527        }
528
529        template <class ..._Args>
530        static constexpr bool __enable_implicit() {
531            return
532                __tuple_convertible<
533                    tuple<_Args...>,
534                    typename __make_tuple_types<tuple,
535                             sizeof...(_Args) < sizeof...(_Tp) ?
536                                 sizeof...(_Args) :
537                                 sizeof...(_Tp)>::type
538                >::value &&
539                __all_default_constructible<
540                    typename __make_tuple_types<tuple, sizeof...(_Tp),
541                             sizeof...(_Args) < sizeof...(_Tp) ?
542                                 sizeof...(_Args) :
543                                 sizeof...(_Tp)>::type
544                >::value;
545        }
546    };
547
548    template <bool _MaybeEnable,
549              bool = sizeof...(_Tp) == 1,
550              class _Dummy = void>
551    struct _CheckTupleLikeConstructor : __check_tuple_constructor_fail {};
552
553    template <class _Dummy>
554    struct _CheckTupleLikeConstructor<true, false, _Dummy>
555    {
556        template <class _Tuple>
557        static constexpr bool __enable_implicit() {
558            return __tuple_convertible<_Tuple, tuple>::value;
559        }
560
561        template <class _Tuple>
562        static constexpr bool __enable_explicit() {
563            return __tuple_constructible<_Tuple, tuple>::value
564               && !__tuple_convertible<_Tuple, tuple>::value;
565        }
566    };
567
568    template <class _Dummy>
569    struct _CheckTupleLikeConstructor<true, true, _Dummy>
570    {
571        // This trait is used to disable the tuple-like constructor when
572        // the UTypes... constructor should be selected instead.
573        // See LWG issue #2549.
574        template <class _Tuple>
575        using _PreferTupleLikeConstructor = __lazy_or<
576            // Don't attempt the two checks below if the tuple we are given
577            // has the same type as this tuple.
578            is_same<typename __uncvref<_Tuple>::type, tuple>,
579            __lazy_and<
580                __lazy_not<is_constructible<_Tp..., _Tuple>>,
581                __lazy_not<is_convertible<_Tuple, _Tp...>>
582            >
583        >;
584
585        template <class _Tuple>
586        static constexpr bool __enable_implicit() {
587            return __lazy_and<
588                __tuple_convertible<_Tuple, tuple>,
589                _PreferTupleLikeConstructor<_Tuple>
590            >::value;
591        }
592
593        template <class _Tuple>
594        static constexpr bool __enable_explicit() {
595            return __lazy_and<
596                __tuple_constructible<_Tuple, tuple>,
597                _PreferTupleLikeConstructor<_Tuple>,
598                __lazy_not<__tuple_convertible<_Tuple, tuple>>
599            >::value;
600        }
601    };
602
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;
607    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
608        typename tuple_element<_Jp, tuple<_Up...> >::type&& get(tuple<_Up...>&&) _NOEXCEPT;
609    template <size_t _Jp, class ..._Up> friend _LIBCPP_CONSTEXPR_AFTER_CXX11
610        const typename tuple_element<_Jp, tuple<_Up...> >::type&& get(const tuple<_Up...>&&) _NOEXCEPT;
611public:
612
613    template <bool _Dummy = true, class = typename enable_if<
614        _CheckArgsConstructor<_Dummy>::template __enable_default<_Tp...>()
615    >::type>
616    _LIBCPP_INLINE_VISIBILITY
617    _LIBCPP_CONSTEXPR tuple()
618        _NOEXCEPT_(__all<is_nothrow_default_constructible<_Tp>::value...>::value) {}
619
620    tuple(tuple const&) = default;
621    tuple(tuple&&) = default;
622
623    template <class _AllocArgT, class _Alloc, bool _Dummy = true, class = typename enable_if<
624        __lazy_and<
625            is_same<allocator_arg_t, _AllocArgT>,
626            __lazy_all<__dependent_type<is_default_constructible<_Tp>, _Dummy>...>
627       >::value
628    >::type>
629    _LIBCPP_INLINE_VISIBILITY
630    tuple(_AllocArgT, _Alloc const& __a)
631      : base_(allocator_arg_t(), __a,
632                    __tuple_indices<>(), __tuple_types<>(),
633                    typename __make_tuple_indices<sizeof...(_Tp), 0>::type(),
634                    __tuple_types<_Tp...>()) {}
635
636    template <bool _Dummy = true,
637              typename enable_if
638                      <
639                         _CheckArgsConstructor<
640                            _Dummy
641                         >::template __enable_implicit<_Tp const&...>(),
642                         bool
643                      >::type = false
644        >
645    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
646    tuple(const _Tp& ... __t) _NOEXCEPT_((__all<is_nothrow_copy_constructible<_Tp>::value...>::value))
647        : base_(typename __make_tuple_indices<sizeof...(_Tp)>::type(),
648                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
649                typename __make_tuple_indices<0>::type(),
650                typename __make_tuple_types<tuple, 0>::type(),
651                __t...
652               ) {}
653
654    template <bool _Dummy = true,
655              typename enable_if
656                      <
657                         _CheckArgsConstructor<
658                            _Dummy
659                         >::template __enable_explicit<_Tp const&...>(),
660                         bool
661                      >::type = false
662        >
663    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
664    explicit tuple(const _Tp& ... __t) _NOEXCEPT_((__all<is_nothrow_copy_constructible<_Tp>::value...>::value))
665        : base_(typename __make_tuple_indices<sizeof...(_Tp)>::type(),
666                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
667                typename __make_tuple_indices<0>::type(),
668                typename __make_tuple_types<tuple, 0>::type(),
669                __t...
670               ) {}
671
672    template <class _Alloc, bool _Dummy = true,
673              typename enable_if
674                      <
675                         _CheckArgsConstructor<
676                            _Dummy
677                         >::template __enable_implicit<_Tp const&...>(),
678                         bool
679                      >::type = false
680        >
681      _LIBCPP_INLINE_VISIBILITY
682      tuple(allocator_arg_t, const _Alloc& __a, const _Tp& ... __t)
683        : base_(allocator_arg_t(), __a,
684                typename __make_tuple_indices<sizeof...(_Tp)>::type(),
685                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
686                typename __make_tuple_indices<0>::type(),
687                typename __make_tuple_types<tuple, 0>::type(),
688                __t...
689               ) {}
690
691    template <class _Alloc, bool _Dummy = true,
692              typename enable_if
693                      <
694                         _CheckArgsConstructor<
695                            _Dummy
696                         >::template __enable_explicit<_Tp const&...>(),
697                         bool
698                      >::type = false
699        >
700      _LIBCPP_INLINE_VISIBILITY
701      explicit
702      tuple(allocator_arg_t, const _Alloc& __a, const _Tp& ... __t)
703        : base_(allocator_arg_t(), __a,
704                typename __make_tuple_indices<sizeof...(_Tp)>::type(),
705                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
706                typename __make_tuple_indices<0>::type(),
707                typename __make_tuple_types<tuple, 0>::type(),
708                __t...
709               ) {}
710
711    template <class ..._Up,
712              bool _PackIsTuple = _PackExpandsToThisTuple<_Up...>::value,
713              typename enable_if
714                      <
715                         _CheckArgsConstructor<
716                             sizeof...(_Up) == sizeof...(_Tp)
717                             && !_PackIsTuple
718                         >::template __enable_implicit<_Up...>() ||
719                        _CheckArgsConstructor<
720                            _EnableImplicitReducedArityExtension
721                            && sizeof...(_Up) < sizeof...(_Tp)
722                            && !_PackIsTuple
723                         >::template __enable_implicit<_Up...>(),
724                         bool
725                      >::type = false
726             >
727        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
728        tuple(_Up&&... __u)
729            _NOEXCEPT_((
730                is_nothrow_constructible<base,
731                    typename __make_tuple_indices<sizeof...(_Up)>::type,
732                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type,
733                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type,
734                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type,
735                    _Up...
736                >::value
737            ))
738            : base_(typename __make_tuple_indices<sizeof...(_Up)>::type(),
739                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
740                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
741                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
742                    _VSTD::forward<_Up>(__u)...) {}
743
744    template <class ..._Up,
745              typename enable_if
746                      <
747                         _CheckArgsConstructor<
748                             sizeof...(_Up) <= sizeof...(_Tp)
749                             && !_PackExpandsToThisTuple<_Up...>::value
750                         >::template __enable_explicit<_Up...>() ||
751                         _CheckArgsConstructor<
752                            !_EnableImplicitReducedArityExtension
753                            && sizeof...(_Up) < sizeof...(_Tp)
754                            && !_PackExpandsToThisTuple<_Up...>::value
755                         >::template __enable_implicit<_Up...>(),
756                         bool
757                      >::type = false
758             >
759        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
760        explicit
761        tuple(_Up&&... __u)
762            _NOEXCEPT_((
763                is_nothrow_constructible<base,
764                    typename __make_tuple_indices<sizeof...(_Up)>::type,
765                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type,
766                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type,
767                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type,
768                    _Up...
769                >::value
770            ))
771            : base_(typename __make_tuple_indices<sizeof...(_Up)>::type(),
772                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
773                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
774                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
775                    _VSTD::forward<_Up>(__u)...) {}
776
777    template <class _Alloc, class ..._Up,
778              typename enable_if
779                      <
780                         _CheckArgsConstructor<
781                             sizeof...(_Up) == sizeof...(_Tp) &&
782                             !_PackExpandsToThisTuple<_Up...>::value
783                         >::template __enable_implicit<_Up...>(),
784                         bool
785                      >::type = false
786             >
787        _LIBCPP_INLINE_VISIBILITY
788        tuple(allocator_arg_t, const _Alloc& __a, _Up&&... __u)
789            : base_(allocator_arg_t(), __a,
790                    typename __make_tuple_indices<sizeof...(_Up)>::type(),
791                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
792                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
793                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
794                    _VSTD::forward<_Up>(__u)...) {}
795
796    template <class _Alloc, class ..._Up,
797              typename enable_if
798                      <
799                         _CheckArgsConstructor<
800                             sizeof...(_Up) == sizeof...(_Tp) &&
801                             !_PackExpandsToThisTuple<_Up...>::value
802                         >::template __enable_explicit<_Up...>(),
803                         bool
804                      >::type = false
805             >
806        _LIBCPP_INLINE_VISIBILITY
807        explicit
808        tuple(allocator_arg_t, const _Alloc& __a, _Up&&... __u)
809            : base_(allocator_arg_t(), __a,
810                    typename __make_tuple_indices<sizeof...(_Up)>::type(),
811                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
812                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
813                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
814                    _VSTD::forward<_Up>(__u)...) {}
815
816    template <class _Tuple,
817              typename enable_if
818                      <
819                         _CheckTupleLikeConstructor<
820                             __tuple_like_with_size<_Tuple, sizeof...(_Tp)>::value
821                             && !_PackExpandsToThisTuple<_Tuple>::value
822                         >::template __enable_implicit<_Tuple>(),
823                         bool
824                      >::type = false
825             >
826        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
827        tuple(_Tuple&& __t) _NOEXCEPT_((is_nothrow_constructible<base, _Tuple>::value))
828            : base_(_VSTD::forward<_Tuple>(__t)) {}
829
830    template <class _Tuple,
831              typename enable_if
832                      <
833                         _CheckTupleLikeConstructor<
834                             __tuple_like_with_size<_Tuple, sizeof...(_Tp)>::value
835                             && !_PackExpandsToThisTuple<_Tuple>::value
836                         >::template __enable_explicit<_Tuple>(),
837                         bool
838                      >::type = false
839             >
840        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
841        explicit
842        tuple(_Tuple&& __t) _NOEXCEPT_((is_nothrow_constructible<base, _Tuple>::value))
843            : base_(_VSTD::forward<_Tuple>(__t)) {}
844
845    template <class _Alloc, class _Tuple,
846              typename enable_if
847                      <
848                         _CheckTupleLikeConstructor<
849                             __tuple_like_with_size<_Tuple, sizeof...(_Tp)>::value
850                         >::template __enable_implicit<_Tuple>(),
851                         bool
852                      >::type = false
853             >
854        _LIBCPP_INLINE_VISIBILITY
855        tuple(allocator_arg_t, const _Alloc& __a, _Tuple&& __t)
856            : base_(allocator_arg_t(), __a, _VSTD::forward<_Tuple>(__t)) {}
857
858    template <class _Alloc, class _Tuple,
859              typename enable_if
860                      <
861                         _CheckTupleLikeConstructor<
862                             __tuple_like_with_size<_Tuple, sizeof...(_Tp)>::value
863                         >::template __enable_explicit<_Tuple>(),
864                         bool
865                      >::type = false
866             >
867        _LIBCPP_INLINE_VISIBILITY
868        explicit
869        tuple(allocator_arg_t, const _Alloc& __a, _Tuple&& __t)
870            : base_(allocator_arg_t(), __a, _VSTD::forward<_Tuple>(__t)) {}
871
872    using _CanCopyAssign = __all<is_copy_assignable<_Tp>::value...>;
873    using _CanMoveAssign = __all<is_move_assignable<_Tp>::value...>;
874
875    _LIBCPP_INLINE_VISIBILITY
876    tuple& operator=(typename conditional<_CanCopyAssign::value, tuple, __nat>::type const& __t)
877        _NOEXCEPT_((__all<is_nothrow_copy_assignable<_Tp>::value...>::value))
878    {
879        base_.operator=(__t.base_);
880        return *this;
881    }
882
883    _LIBCPP_INLINE_VISIBILITY
884    tuple& operator=(typename conditional<_CanMoveAssign::value, tuple, __nat>::type&& __t)
885        _NOEXCEPT_((__all<is_nothrow_move_assignable<_Tp>::value...>::value))
886    {
887        base_.operator=(static_cast<base&&>(__t.base_));
888        return *this;
889    }
890
891    template <class _Tuple,
892              class = typename enable_if
893                      <
894                         __tuple_assignable<_Tuple, tuple>::value
895                      >::type
896             >
897        _LIBCPP_INLINE_VISIBILITY
898        tuple&
899        operator=(_Tuple&& __t) _NOEXCEPT_((is_nothrow_assignable<base&, _Tuple>::value))
900        {
901            base_.operator=(_VSTD::forward<_Tuple>(__t));
902            return *this;
903        }
904
905    _LIBCPP_INLINE_VISIBILITY
906    void swap(tuple& __t) _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
907        {base_.swap(__t.base_);}
908};
909
910template <>
911class _LIBCPP_TEMPLATE_VIS tuple<>
912{
913public:
914    _LIBCPP_INLINE_VISIBILITY
915    _LIBCPP_CONSTEXPR tuple() _NOEXCEPT {}
916    template <class _Alloc>
917    _LIBCPP_INLINE_VISIBILITY
918        tuple(allocator_arg_t, const _Alloc&) _NOEXCEPT {}
919    template <class _Alloc>
920    _LIBCPP_INLINE_VISIBILITY
921        tuple(allocator_arg_t, const _Alloc&, const tuple&) _NOEXCEPT {}
922    template <class _Up>
923    _LIBCPP_INLINE_VISIBILITY
924        tuple(array<_Up, 0>) _NOEXCEPT {}
925    template <class _Alloc, class _Up>
926    _LIBCPP_INLINE_VISIBILITY
927        tuple(allocator_arg_t, const _Alloc&, array<_Up, 0>) _NOEXCEPT {}
928    _LIBCPP_INLINE_VISIBILITY
929    void swap(tuple&) _NOEXCEPT {}
930};
931
932template <class ..._Tp>
933inline _LIBCPP_INLINE_VISIBILITY
934typename enable_if
935<
936    __all<__is_swappable<_Tp>::value...>::value,
937    void
938>::type
939swap(tuple<_Tp...>& __t, tuple<_Tp...>& __u)
940                 _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
941    {__t.swap(__u);}
942
943// get
944
945template <size_t _Ip, class ..._Tp>
946inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
947typename tuple_element<_Ip, tuple<_Tp...> >::type&
948get(tuple<_Tp...>& __t) _NOEXCEPT
949{
950    typedef typename tuple_element<_Ip, tuple<_Tp...> >::type type;
951    return static_cast<__tuple_leaf<_Ip, type>&>(__t.base_).get();
952}
953
954template <size_t _Ip, class ..._Tp>
955inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
956const typename tuple_element<_Ip, tuple<_Tp...> >::type&
957get(const tuple<_Tp...>& __t) _NOEXCEPT
958{
959    typedef typename tuple_element<_Ip, tuple<_Tp...> >::type type;
960    return static_cast<const __tuple_leaf<_Ip, type>&>(__t.base_).get();
961}
962
963template <size_t _Ip, class ..._Tp>
964inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
965typename tuple_element<_Ip, tuple<_Tp...> >::type&&
966get(tuple<_Tp...>&& __t) _NOEXCEPT
967{
968    typedef typename tuple_element<_Ip, tuple<_Tp...> >::type type;
969    return static_cast<type&&>(
970             static_cast<__tuple_leaf<_Ip, type>&&>(__t.base_).get());
971}
972
973template <size_t _Ip, class ..._Tp>
974inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
975const typename tuple_element<_Ip, tuple<_Tp...> >::type&&
976get(const tuple<_Tp...>&& __t) _NOEXCEPT
977{
978    typedef typename tuple_element<_Ip, tuple<_Tp...> >::type type;
979    return static_cast<const type&&>(
980             static_cast<const __tuple_leaf<_Ip, type>&&>(__t.base_).get());
981}
982
983#if _LIBCPP_STD_VER > 11
984
985namespace __find_detail {
986
987static constexpr size_t __not_found = -1;
988static constexpr size_t __ambiguous = __not_found - 1;
989
990inline _LIBCPP_INLINE_VISIBILITY
991constexpr size_t __find_idx_return(size_t __curr_i, size_t __res, bool __matches) {
992    return !__matches ? __res :
993        (__res == __not_found ? __curr_i : __ambiguous);
994}
995
996template <size_t _Nx>
997inline _LIBCPP_INLINE_VISIBILITY
998constexpr size_t __find_idx(size_t __i, const bool (&__matches)[_Nx]) {
999  return __i == _Nx ? __not_found :
1000      __find_idx_return(__i, __find_idx(__i + 1, __matches), __matches[__i]);
1001}
1002
1003template <class _T1, class ..._Args>
1004struct __find_exactly_one_checked {
1005  static constexpr bool __matches[] = {is_same<_T1, _Args>::value...};
1006    static constexpr size_t value = __find_detail::__find_idx(0, __matches);
1007    static_assert (value != __not_found, "type not found in type list" );
1008    static_assert(value != __ambiguous,"type occurs more than once in type list");
1009};
1010
1011template <class _T1>
1012struct __find_exactly_one_checked<_T1> {
1013    static_assert(!is_same<_T1, _T1>::value, "type not in empty type list");
1014};
1015
1016} // namespace __find_detail;
1017
1018template <typename _T1, typename... _Args>
1019struct __find_exactly_one_t
1020    : public __find_detail::__find_exactly_one_checked<_T1, _Args...> {
1021};
1022
1023template <class _T1, class... _Args>
1024inline _LIBCPP_INLINE_VISIBILITY
1025constexpr _T1& get(tuple<_Args...>& __tup) noexcept
1026{
1027    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(__tup);
1028}
1029
1030template <class _T1, class... _Args>
1031inline _LIBCPP_INLINE_VISIBILITY
1032constexpr _T1 const& get(tuple<_Args...> const& __tup) noexcept
1033{
1034    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(__tup);
1035}
1036
1037template <class _T1, class... _Args>
1038inline _LIBCPP_INLINE_VISIBILITY
1039constexpr _T1&& get(tuple<_Args...>&& __tup) noexcept
1040{
1041    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(_VSTD::move(__tup));
1042}
1043
1044template <class _T1, class... _Args>
1045inline _LIBCPP_INLINE_VISIBILITY
1046constexpr _T1 const&& get(tuple<_Args...> const&& __tup) noexcept
1047{
1048    return _VSTD::get<__find_exactly_one_t<_T1, _Args...>::value>(_VSTD::move(__tup));
1049}
1050
1051#endif
1052
1053// tie
1054
1055template <class ..._Tp>
1056inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1057tuple<_Tp&...>
1058tie(_Tp&... __t) _NOEXCEPT
1059{
1060    return tuple<_Tp&...>(__t...);
1061}
1062
1063template <class _Up>
1064struct __ignore_t
1065{
1066    template <class _Tp>
1067    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1068    const __ignore_t& operator=(_Tp&&) const {return *this;}
1069};
1070
1071namespace {
1072  constexpr __ignore_t<unsigned char> ignore = __ignore_t<unsigned char>();
1073}
1074
1075template <class _Tp>
1076struct __make_tuple_return_impl
1077{
1078    typedef _Tp type;
1079};
1080
1081template <class _Tp>
1082struct __make_tuple_return_impl<reference_wrapper<_Tp> >
1083{
1084    typedef _Tp& type;
1085};
1086
1087template <class _Tp>
1088struct __make_tuple_return
1089{
1090    typedef typename __make_tuple_return_impl<typename decay<_Tp>::type>::type type;
1091};
1092
1093template <class... _Tp>
1094inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1095tuple<typename __make_tuple_return<_Tp>::type...>
1096make_tuple(_Tp&&... __t)
1097{
1098    return tuple<typename __make_tuple_return<_Tp>::type...>(_VSTD::forward<_Tp>(__t)...);
1099}
1100
1101template <class... _Tp>
1102inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1103tuple<_Tp&&...>
1104forward_as_tuple(_Tp&&... __t) _NOEXCEPT
1105{
1106    return tuple<_Tp&&...>(_VSTD::forward<_Tp>(__t)...);
1107}
1108
1109template <size_t _Ip>
1110struct __tuple_equal
1111{
1112    template <class _Tp, class _Up>
1113    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1114    bool operator()(const _Tp& __x, const _Up& __y)
1115    {
1116        return __tuple_equal<_Ip - 1>()(__x, __y) && _VSTD::get<_Ip-1>(__x) == _VSTD::get<_Ip-1>(__y);
1117    }
1118};
1119
1120template <>
1121struct __tuple_equal<0>
1122{
1123    template <class _Tp, class _Up>
1124    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1125    bool operator()(const _Tp&, const _Up&)
1126    {
1127        return true;
1128    }
1129};
1130
1131template <class ..._Tp, class ..._Up>
1132inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1133bool
1134operator==(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1135{
1136    return __tuple_equal<sizeof...(_Tp)>()(__x, __y);
1137}
1138
1139template <class ..._Tp, class ..._Up>
1140inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1141bool
1142operator!=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1143{
1144    return !(__x == __y);
1145}
1146
1147template <size_t _Ip>
1148struct __tuple_less
1149{
1150    template <class _Tp, class _Up>
1151    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1152    bool operator()(const _Tp& __x, const _Up& __y)
1153    {
1154        const size_t __idx = tuple_size<_Tp>::value - _Ip;
1155        if (_VSTD::get<__idx>(__x) < _VSTD::get<__idx>(__y))
1156            return true;
1157        if (_VSTD::get<__idx>(__y) < _VSTD::get<__idx>(__x))
1158            return false;
1159        return __tuple_less<_Ip-1>()(__x, __y);
1160    }
1161};
1162
1163template <>
1164struct __tuple_less<0>
1165{
1166    template <class _Tp, class _Up>
1167    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1168    bool operator()(const _Tp&, const _Up&)
1169    {
1170        return false;
1171    }
1172};
1173
1174template <class ..._Tp, class ..._Up>
1175inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1176bool
1177operator<(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1178{
1179    return __tuple_less<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 __y < __x;
1188}
1189
1190template <class ..._Tp, class ..._Up>
1191inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1192bool
1193operator>=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1194{
1195    return !(__x < __y);
1196}
1197
1198template <class ..._Tp, class ..._Up>
1199inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1200bool
1201operator<=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
1202{
1203    return !(__y < __x);
1204}
1205
1206// tuple_cat
1207
1208template <class _Tp, class _Up> struct __tuple_cat_type;
1209
1210template <class ..._Ttypes, class ..._Utypes>
1211struct __tuple_cat_type<tuple<_Ttypes...>, __tuple_types<_Utypes...> >
1212{
1213    typedef tuple<_Ttypes..., _Utypes...> type;
1214};
1215
1216template <class _ResultTuple, bool _Is_Tuple0TupleLike, class ..._Tuples>
1217struct __tuple_cat_return_1
1218{
1219};
1220
1221template <class ..._Types, class _Tuple0>
1222struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0>
1223{
1224    typedef typename __tuple_cat_type<tuple<_Types...>,
1225            typename __make_tuple_types<typename remove_reference<_Tuple0>::type>::type>::type
1226                                                                           type;
1227};
1228
1229template <class ..._Types, class _Tuple0, class _Tuple1, class ..._Tuples>
1230struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0, _Tuple1, _Tuples...>
1231    : public __tuple_cat_return_1<
1232                 typename __tuple_cat_type<
1233                     tuple<_Types...>,
1234                     typename __make_tuple_types<typename remove_reference<_Tuple0>::type>::type
1235                 >::type,
1236                 __tuple_like<typename remove_reference<_Tuple1>::type>::value,
1237                 _Tuple1, _Tuples...>
1238{
1239};
1240
1241template <class ..._Tuples> struct __tuple_cat_return;
1242
1243template <class _Tuple0, class ..._Tuples>
1244struct __tuple_cat_return<_Tuple0, _Tuples...>
1245    : public __tuple_cat_return_1<tuple<>,
1246         __tuple_like<typename remove_reference<_Tuple0>::type>::value, _Tuple0,
1247                                                                     _Tuples...>
1248{
1249};
1250
1251template <>
1252struct __tuple_cat_return<>
1253{
1254    typedef tuple<> type;
1255};
1256
1257inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1258tuple<>
1259tuple_cat()
1260{
1261    return tuple<>();
1262}
1263
1264template <class _Rp, class _Indices, class _Tuple0, class ..._Tuples>
1265struct __tuple_cat_return_ref_imp;
1266
1267template <class ..._Types, size_t ..._I0, class _Tuple0>
1268struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>, _Tuple0>
1269{
1270    typedef typename remove_reference<_Tuple0>::type _T0;
1271    typedef tuple<_Types..., typename __apply_cv<_Tuple0,
1272                          typename tuple_element<_I0, _T0>::type>::type&&...> type;
1273};
1274
1275template <class ..._Types, size_t ..._I0, class _Tuple0, class _Tuple1, class ..._Tuples>
1276struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>,
1277                                  _Tuple0, _Tuple1, _Tuples...>
1278    : public __tuple_cat_return_ref_imp<
1279         tuple<_Types..., typename __apply_cv<_Tuple0,
1280               typename tuple_element<_I0,
1281                  typename remove_reference<_Tuple0>::type>::type>::type&&...>,
1282         typename __make_tuple_indices<tuple_size<typename
1283                                 remove_reference<_Tuple1>::type>::value>::type,
1284         _Tuple1, _Tuples...>
1285{
1286};
1287
1288template <class _Tuple0, class ..._Tuples>
1289struct __tuple_cat_return_ref
1290    : public __tuple_cat_return_ref_imp<tuple<>,
1291               typename __make_tuple_indices<
1292                        tuple_size<typename remove_reference<_Tuple0>::type>::value
1293               >::type, _Tuple0, _Tuples...>
1294{
1295};
1296
1297template <class _Types, class _I0, class _J0>
1298struct __tuple_cat;
1299
1300template <class ..._Types, size_t ..._I0, size_t ..._J0>
1301struct __tuple_cat<tuple<_Types...>, __tuple_indices<_I0...>, __tuple_indices<_J0...> >
1302{
1303    template <class _Tuple0>
1304    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1305    typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&>::type
1306    operator()(tuple<_Types...> __t, _Tuple0&& __t0)
1307    {
1308        return forward_as_tuple(_VSTD::forward<_Types>(_VSTD::get<_I0>(__t))...,
1309                                      _VSTD::get<_J0>(_VSTD::forward<_Tuple0>(__t0))...);
1310    }
1311
1312    template <class _Tuple0, class _Tuple1, class ..._Tuples>
1313    _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1314    typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&, _Tuple1&&, _Tuples&&...>::type
1315    operator()(tuple<_Types...> __t, _Tuple0&& __t0, _Tuple1&& __t1, _Tuples&& ...__tpls)
1316    {
1317        typedef typename remove_reference<_Tuple0>::type _T0;
1318        typedef typename remove_reference<_Tuple1>::type _T1;
1319        return __tuple_cat<
1320           tuple<_Types..., typename __apply_cv<_Tuple0, typename tuple_element<_J0, _T0>::type>::type&&...>,
1321           typename __make_tuple_indices<sizeof ...(_Types) + tuple_size<_T0>::value>::type,
1322           typename __make_tuple_indices<tuple_size<_T1>::value>::type>()
1323                           (forward_as_tuple(
1324                              _VSTD::forward<_Types>(_VSTD::get<_I0>(__t))...,
1325                              _VSTD::get<_J0>(_VSTD::forward<_Tuple0>(__t0))...
1326                            ),
1327                            _VSTD::forward<_Tuple1>(__t1),
1328                            _VSTD::forward<_Tuples>(__tpls)...);
1329    }
1330};
1331
1332template <class _Tuple0, class... _Tuples>
1333inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
1334typename __tuple_cat_return<_Tuple0, _Tuples...>::type
1335tuple_cat(_Tuple0&& __t0, _Tuples&&... __tpls)
1336{
1337    typedef typename remove_reference<_Tuple0>::type _T0;
1338    return __tuple_cat<tuple<>, __tuple_indices<>,
1339                  typename __make_tuple_indices<tuple_size<_T0>::value>::type>()
1340                  (tuple<>(), _VSTD::forward<_Tuple0>(__t0),
1341                                            _VSTD::forward<_Tuples>(__tpls)...);
1342}
1343
1344template <class ..._Tp, class _Alloc>
1345struct _LIBCPP_TEMPLATE_VIS uses_allocator<tuple<_Tp...>, _Alloc>
1346    : true_type {};
1347
1348#endif // _LIBCPP_HAS_NO_VARIADICS
1349
1350#ifndef _LIBCPP_CXX03_LANG
1351template <class _T1, class _T2>
1352template <class... _Args1, class... _Args2, size_t ..._I1, size_t ..._I2>
1353inline _LIBCPP_INLINE_VISIBILITY
1354pair<_T1, _T2>::pair(piecewise_construct_t,
1355                     tuple<_Args1...>& __first_args, tuple<_Args2...>& __second_args,
1356                     __tuple_indices<_I1...>, __tuple_indices<_I2...>)
1357    :  first(_VSTD::forward<_Args1>(_VSTD::get<_I1>( __first_args))...),
1358      second(_VSTD::forward<_Args2>(_VSTD::get<_I2>(__second_args))...)
1359{
1360}
1361#endif // _LIBCPP_CXX03_LANG
1362
1363#if _LIBCPP_STD_VER > 14
1364template <class _Tp>
1365constexpr size_t tuple_size_v = tuple_size<_Tp>::value;
1366
1367#define _LIBCPP_NOEXCEPT_RETURN(...) noexcept(noexcept(__VA_ARGS__)) { return __VA_ARGS__; }
1368
1369template <class _Fn, class _Tuple, size_t ..._Id>
1370inline _LIBCPP_INLINE_VISIBILITY
1371constexpr decltype(auto) __apply_tuple_impl(_Fn && __f, _Tuple && __t,
1372                                            __tuple_indices<_Id...>)
1373_LIBCPP_NOEXCEPT_RETURN(
1374    _VSTD::__invoke_constexpr(
1375        _VSTD::forward<_Fn>(__f),
1376        _VSTD::get<_Id>(_VSTD::forward<_Tuple>(__t))...)
1377)
1378
1379template <class _Fn, class _Tuple>
1380inline _LIBCPP_INLINE_VISIBILITY
1381constexpr decltype(auto) apply(_Fn && __f, _Tuple && __t)
1382_LIBCPP_NOEXCEPT_RETURN(
1383    _VSTD::__apply_tuple_impl(
1384        _VSTD::forward<_Fn>(__f), _VSTD::forward<_Tuple>(__t),
1385        typename __make_tuple_indices<tuple_size_v<decay_t<_Tuple>>>::type{})
1386)
1387
1388template <class _Tp, class _Tuple, size_t... _Idx>
1389inline _LIBCPP_INLINE_VISIBILITY
1390constexpr _Tp __make_from_tuple_impl(_Tuple&& __t, __tuple_indices<_Idx...>)
1391_LIBCPP_NOEXCEPT_RETURN(
1392    _Tp(_VSTD::get<_Idx>(_VSTD::forward<_Tuple>(__t))...)
1393)
1394
1395template <class _Tp, class _Tuple>
1396inline _LIBCPP_INLINE_VISIBILITY
1397constexpr _Tp make_from_tuple(_Tuple&& __t)
1398_LIBCPP_NOEXCEPT_RETURN(
1399    _VSTD::__make_from_tuple_impl<_Tp>(_VSTD::forward<_Tuple>(__t),
1400        typename __make_tuple_indices<tuple_size_v<decay_t<_Tuple>>>::type{})
1401)
1402
1403#undef _LIBCPP_NOEXCEPT_RETURN
1404
1405#endif // _LIBCPP_STD_VER > 14
1406
1407_LIBCPP_END_NAMESPACE_STD
1408
1409#endif  // _LIBCPP_TUPLE
1410