xref: /llvm-project-15.0.7/libcxx/include/tuple (revision 7f01ac39)
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&...);
25    template <class... U>
26        explicit tuple(U&&...);
27    tuple(const tuple&) = default;
28    tuple(tuple&&) = default;
29    template <class... U>
30        tuple(const tuple<U...>&);
31    template <class... U>
32        tuple(tuple<U...>&&);
33    template <class U1, class U2>
34        tuple(const pair<U1, U2>&); // iff sizeof...(T) == 2
35    template <class U1, class U2>
36        tuple(pair<U1, U2>&&); // iff sizeof...(T) == 2
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&&...);
76template <class... T> tuple<ATypes...> forward_as_tuple(T&&...) noexcept;
77template <class... T> tuple<T&...> tie(T&...) noexcept;
78template <class... Tuples> tuple<CTypes...> tuple_cat(Tuples&&... tpls);
79
80// 20.4.1.4, tuple helper classes:
81template <class T> class tuple_size; // undefined
82template <class... T> class tuple_size<tuple<T...>>;
83template <intsize_t I, class T> class tuple_element; // undefined
84template <intsize_t I, class... T> class tuple_element<I, tuple<T...>>;
85
86// 20.4.1.5, element access:
87template <intsize_t I, class... T>
88    typename tuple_element<I, tuple<T...>>::type&
89    get(tuple<T...>&) noexcept;
90template <intsize_t I, class... T>
91    typename tuple_element<I, tuple<T...>>::type const&
92    get(const tuple<T...>&) noexcept;
93template <intsize_t I, class... T>
94    typename tuple_element<I, tuple<T...>>::type&&
95    get(tuple<T...>&&) noexcept;
96
97// 20.4.1.6, relational operators:
98template<class... T, class... U> bool operator==(const tuple<T...>&, const tuple<U...>&);
99template<class... T, class... U> bool operator<(const tuple<T...>&, const tuple<U...>&);
100template<class... T, class... U> bool operator!=(const tuple<T...>&, const tuple<U...>&);
101template<class... T, class... U> bool operator>(const tuple<T...>&, const tuple<U...>&);
102template<class... T, class... U> bool operator<=(const tuple<T...>&, const tuple<U...>&);
103template<class... T, class... U> bool operator>=(const tuple<T...>&, const tuple<U...>&);
104
105template <class... Types, class Alloc>
106  struct uses_allocator<tuple<Types...>, Alloc>;
107
108template <class... Types>
109  void
110  swap(tuple<Types...>& x, tuple<Types...>& y) noexcept(noexcept(x.swap(y)));
111
112}  // std
113
114*/
115
116#include <__config>
117#include <__tuple>
118#include <cstddef>
119#include <memory>
120#include <type_traits>
121
122#pragma GCC system_header
123
124_LIBCPP_BEGIN_NAMESPACE_STD
125
126#ifndef _LIBCPP_HAS_NO_VARIADICS
127
128// tuple_size
129
130template <class ..._Tp>
131class _LIBCPP_VISIBLE tuple_size<tuple<_Tp...> >
132    : public integral_constant<size_t, sizeof...(_Tp)>
133{
134};
135
136// tuple_element
137
138template <size_t _Ip, class ..._Tp>
139class _LIBCPP_VISIBLE tuple_element<_Ip, tuple<_Tp...> >
140{
141public:
142    typedef typename tuple_element<_Ip, __tuple_types<_Tp...> >::type type;
143};
144
145// __tuple_leaf
146
147template <size_t _Ip, class _Hp, bool=is_empty<_Hp>::value>
148class __tuple_leaf;
149
150template <size_t _Ip, class _Hp, bool _Ep>
151inline _LIBCPP_INLINE_VISIBILITY
152void swap(__tuple_leaf<_Ip, _Hp, _Ep>& __x, __tuple_leaf<_Ip, _Hp, _Ep>& __y)
153    _NOEXCEPT_(__is_nothrow_swappable<_Hp>::value)
154{
155    swap(__x.get(), __y.get());
156}
157
158template <size_t _Ip, class _Hp, bool>
159class __tuple_leaf
160{
161    _Hp value;
162
163    __tuple_leaf& operator=(const __tuple_leaf&);
164public:
165    _LIBCPP_INLINE_VISIBILITY __tuple_leaf() : value()
166       {static_assert(!is_reference<_Hp>::value,
167              "Attempted to default construct a reference element in a tuple");}
168
169    template <class _Alloc>
170        _LIBCPP_INLINE_VISIBILITY
171        __tuple_leaf(integral_constant<int, 0>, const _Alloc&)
172            : value()
173        {static_assert(!is_reference<_Hp>::value,
174              "Attempted to default construct a reference element in a tuple");}
175
176    template <class _Alloc>
177        _LIBCPP_INLINE_VISIBILITY
178        __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a)
179            : value(allocator_arg_t(), __a)
180        {static_assert(!is_reference<_Hp>::value,
181              "Attempted to default construct a reference element in a tuple");}
182
183    template <class _Alloc>
184        _LIBCPP_INLINE_VISIBILITY
185        __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a)
186            : value(__a)
187        {static_assert(!is_reference<_Hp>::value,
188              "Attempted to default construct a reference element in a tuple");}
189
190    template <class _Tp,
191              class = typename enable_if<is_constructible<_Hp, _Tp>::value>::type>
192        _LIBCPP_INLINE_VISIBILITY
193        explicit __tuple_leaf(_Tp&& __t)
194            : value(_VSTD::forward<_Tp>(__t))
195        {static_assert(!is_reference<_Hp>::value ||
196                        is_lvalue_reference<_Hp>::value &&
197                        (is_lvalue_reference<_Tp>::value ||
198                         is_same<typename remove_reference<_Tp>::type,
199                                 reference_wrapper<
200                                    typename remove_reference<_Hp>::type
201                                 >
202                                >::value) ||
203                        (is_rvalue_reference<_Hp>::value &&
204                         !is_lvalue_reference<_Tp>::value),
205       "Attempted to construct a reference element in a tuple with an rvalue");}
206
207    template <class _Tp, class _Alloc>
208        _LIBCPP_INLINE_VISIBILITY
209        explicit __tuple_leaf(integral_constant<int, 0>, const _Alloc&, _Tp&& __t)
210            : value(_VSTD::forward<_Tp>(__t))
211        {static_assert(!is_lvalue_reference<_Hp>::value ||
212                        is_lvalue_reference<_Hp>::value &&
213                        (is_lvalue_reference<_Tp>::value ||
214                         is_same<typename remove_reference<_Tp>::type,
215                                 reference_wrapper<
216                                    typename remove_reference<_Hp>::type
217                                 >
218                                >::value),
219       "Attempted to construct a reference element in a tuple with an rvalue");}
220
221    template <class _Tp, class _Alloc>
222        _LIBCPP_INLINE_VISIBILITY
223        explicit __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a, _Tp&& __t)
224            : value(allocator_arg_t(), __a, _VSTD::forward<_Tp>(__t))
225        {static_assert(!is_lvalue_reference<_Hp>::value ||
226                        is_lvalue_reference<_Hp>::value &&
227                        (is_lvalue_reference<_Tp>::value ||
228                         is_same<typename remove_reference<_Tp>::type,
229                                 reference_wrapper<
230                                    typename remove_reference<_Hp>::type
231                                 >
232                                >::value),
233       "Attempted to construct a reference element in a tuple with an rvalue");}
234
235    template <class _Tp, class _Alloc>
236        _LIBCPP_INLINE_VISIBILITY
237        explicit __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a, _Tp&& __t)
238            : value(_VSTD::forward<_Tp>(__t), __a)
239        {static_assert(!is_lvalue_reference<_Hp>::value ||
240                        is_lvalue_reference<_Hp>::value &&
241                        (is_lvalue_reference<_Tp>::value ||
242                         is_same<typename remove_reference<_Tp>::type,
243                                 reference_wrapper<
244                                    typename remove_reference<_Hp>::type
245                                 >
246                                >::value),
247       "Attempted to construct a reference element in a tuple with an rvalue");}
248
249    __tuple_leaf(const __tuple_leaf& __t)
250        : value(__t.get())
251        {static_assert(!is_rvalue_reference<_Hp>::value, "Can not copy a tuple with rvalue reference member");}
252
253    template <class _Tp>
254        _LIBCPP_INLINE_VISIBILITY
255        explicit __tuple_leaf(const __tuple_leaf<_Ip, _Tp>& __t)
256            : value(__t.get()) {}
257
258    template <class _Tp>
259        _LIBCPP_INLINE_VISIBILITY
260        __tuple_leaf&
261        operator=(_Tp&& __t)
262        {
263            value = _VSTD::forward<_Tp>(__t);
264            return *this;
265        }
266
267    _LIBCPP_INLINE_VISIBILITY
268    int swap(__tuple_leaf& __t) _NOEXCEPT_(__is_nothrow_swappable<__tuple_leaf>::value)
269    {
270        _VSTD::swap(*this, __t);
271        return 0;
272    }
273
274    _LIBCPP_INLINE_VISIBILITY       _Hp& get()       {return value;}
275    _LIBCPP_INLINE_VISIBILITY const _Hp& get() const {return value;}
276};
277
278template <size_t _Ip, class _Hp>
279class __tuple_leaf<_Ip, _Hp, true>
280    : private _Hp
281{
282
283    __tuple_leaf& operator=(const __tuple_leaf&);
284public:
285    _LIBCPP_INLINE_VISIBILITY __tuple_leaf() {}
286
287    template <class _Alloc>
288        _LIBCPP_INLINE_VISIBILITY
289        __tuple_leaf(integral_constant<int, 0>, const _Alloc&) {}
290
291    template <class _Alloc>
292        _LIBCPP_INLINE_VISIBILITY
293        __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a)
294            : _Hp(allocator_arg_t(), __a) {}
295
296    template <class _Alloc>
297        _LIBCPP_INLINE_VISIBILITY
298        __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a)
299            : _Hp(__a) {}
300
301    template <class _Tp,
302              class = typename enable_if<is_constructible<_Hp, _Tp>::value>::type>
303        _LIBCPP_INLINE_VISIBILITY
304        explicit __tuple_leaf(_Tp&& __t)
305            : _Hp(_VSTD::forward<_Tp>(__t)) {}
306
307    template <class _Tp, class _Alloc>
308        _LIBCPP_INLINE_VISIBILITY
309        explicit __tuple_leaf(integral_constant<int, 0>, const _Alloc&, _Tp&& __t)
310            : _Hp(_VSTD::forward<_Tp>(__t)) {}
311
312    template <class _Tp, class _Alloc>
313        _LIBCPP_INLINE_VISIBILITY
314        explicit __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a, _Tp&& __t)
315            : _Hp(allocator_arg_t(), __a, _VSTD::forward<_Tp>(__t)) {}
316
317    template <class _Tp, class _Alloc>
318        _LIBCPP_INLINE_VISIBILITY
319        explicit __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a, _Tp&& __t)
320            : _Hp(_VSTD::forward<_Tp>(__t), __a) {}
321
322    template <class _Tp>
323        _LIBCPP_INLINE_VISIBILITY
324        explicit __tuple_leaf(const __tuple_leaf<_Ip, _Tp>& __t)
325            : _Hp(__t.get()) {}
326
327    template <class _Tp>
328        _LIBCPP_INLINE_VISIBILITY
329        __tuple_leaf&
330        operator=(_Tp&& __t)
331        {
332            _Hp::operator=(_VSTD::forward<_Tp>(__t));
333            return *this;
334        }
335
336    _LIBCPP_INLINE_VISIBILITY
337    int
338    swap(__tuple_leaf& __t) _NOEXCEPT_(__is_nothrow_swappable<__tuple_leaf>::value)
339    {
340        _VSTD::swap(*this, __t);
341        return 0;
342    }
343
344    _LIBCPP_INLINE_VISIBILITY       _Hp& get()       {return static_cast<_Hp&>(*this);}
345    _LIBCPP_INLINE_VISIBILITY const _Hp& get() const {return static_cast<const _Hp&>(*this);}
346};
347
348template <class ..._Tp>
349_LIBCPP_INLINE_VISIBILITY
350void __swallow(_Tp&&...) {}
351
352template <bool ...> struct __all;
353
354template <>
355struct __all<>
356{
357    static const bool value = true;
358};
359
360template <bool _B0, bool ... _B>
361struct __all<_B0, _B...>
362{
363    static const bool value = _B0 && __all<_B...>::value;
364};
365
366// __tuple_impl
367
368template<class _Indx, class ..._Tp> struct __tuple_impl;
369
370template<size_t ..._Indx, class ..._Tp>
371struct __tuple_impl<__tuple_indices<_Indx...>, _Tp...>
372    : public __tuple_leaf<_Indx, _Tp>...
373{
374    template <size_t ..._Uf, class ..._Tf,
375              size_t ..._Ul, class ..._Tl, class ..._Up>
376        _LIBCPP_INLINE_VISIBILITY
377        explicit
378        __tuple_impl(__tuple_indices<_Uf...>, __tuple_types<_Tf...>,
379                     __tuple_indices<_Ul...>, __tuple_types<_Tl...>,
380                     _Up&&... __u) :
381            __tuple_leaf<_Uf, _Tf>(_VSTD::forward<_Up>(__u))...,
382            __tuple_leaf<_Ul, _Tl>()...
383            {}
384
385    template <class _Alloc, size_t ..._Uf, class ..._Tf,
386              size_t ..._Ul, class ..._Tl, class ..._Up>
387        _LIBCPP_INLINE_VISIBILITY
388        explicit
389        __tuple_impl(allocator_arg_t, const _Alloc& __a,
390                     __tuple_indices<_Uf...>, __tuple_types<_Tf...>,
391                     __tuple_indices<_Ul...>, __tuple_types<_Tl...>,
392                     _Up&&... __u) :
393            __tuple_leaf<_Uf, _Tf>(__uses_alloc_ctor<_Tf, _Alloc, _Up>(), __a,
394            _VSTD::forward<_Up>(__u))...,
395            __tuple_leaf<_Ul, _Tl>(__uses_alloc_ctor<_Tl, _Alloc>(), __a)...
396            {}
397
398    template <class _Tuple,
399              class = typename enable_if
400                      <
401                         __tuple_convertible<_Tuple, tuple<_Tp...> >::value
402                      >::type
403             >
404        _LIBCPP_INLINE_VISIBILITY
405        __tuple_impl(_Tuple&& __t)
406            : __tuple_leaf<_Indx, _Tp>(_VSTD::forward<typename tuple_element<_Indx,
407                                       typename __make_tuple_types<_Tuple>::type>::type>(_VSTD::get<_Indx>(__t)))...
408            {}
409
410    template <class _Alloc, class _Tuple,
411              class = typename enable_if
412                      <
413                         __tuple_convertible<_Tuple, tuple<_Tp...> >::value
414                      >::type
415             >
416        _LIBCPP_INLINE_VISIBILITY
417        __tuple_impl(allocator_arg_t, const _Alloc& __a, _Tuple&& __t)
418            : __tuple_leaf<_Indx, _Tp>(__uses_alloc_ctor<_Tp, _Alloc, typename tuple_element<_Indx,
419                                       typename __make_tuple_types<_Tuple>::type>::type>(), __a,
420                                       _VSTD::forward<typename tuple_element<_Indx,
421                                       typename __make_tuple_types<_Tuple>::type>::type>(_VSTD::get<_Indx>(__t)))...
422            {}
423
424    template <class _Tuple>
425        _LIBCPP_INLINE_VISIBILITY
426        typename enable_if
427        <
428            __tuple_assignable<_Tuple, tuple<_Tp...> >::value,
429            __tuple_impl&
430        >::type
431        operator=(_Tuple&& __t)
432        {
433            __swallow(__tuple_leaf<_Indx, _Tp>::operator=(_VSTD::forward<typename tuple_element<_Indx,
434                                       typename __make_tuple_types<_Tuple>::type>::type>(_VSTD::get<_Indx>(__t)))...);
435            return *this;
436        }
437
438    _LIBCPP_INLINE_VISIBILITY
439    void swap(__tuple_impl& __t)
440        _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
441    {
442        __swallow(__tuple_leaf<_Indx, _Tp>::swap(static_cast<__tuple_leaf<_Indx, _Tp>&>(__t))...);
443    }
444};
445
446template <class ..._Tp>
447class _LIBCPP_VISIBLE tuple
448{
449    typedef __tuple_impl<typename __make_tuple_indices<sizeof...(_Tp)>::type, _Tp...> base;
450
451    base base_;
452
453    template <size_t _Jp, class ..._Up> friend
454        typename tuple_element<_Jp, tuple<_Up...> >::type& get(tuple<_Up...>&);
455    template <size_t _Jp, class ..._Up> friend
456        const typename tuple_element<_Jp, tuple<_Up...> >::type& get(const tuple<_Up...>&);
457    template <size_t _Jp, class ..._Up> friend
458        typename tuple_element<_Jp, tuple<_Up...> >::type&& get(tuple<_Up...>&&);
459public:
460
461    _LIBCPP_INLINE_VISIBILITY
462    explicit tuple(const _Tp& ... __t)
463        : base_(typename __make_tuple_indices<sizeof...(_Tp)>::type(),
464                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
465                typename __make_tuple_indices<0>::type(),
466                typename __make_tuple_types<tuple, 0>::type(),
467                __t...
468               ) {}
469
470    template <class _Alloc>
471      _LIBCPP_INLINE_VISIBILITY
472      tuple(allocator_arg_t, const _Alloc& __a, const _Tp& ... __t)
473        : base_(allocator_arg_t(), __a,
474                typename __make_tuple_indices<sizeof...(_Tp)>::type(),
475                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
476                typename __make_tuple_indices<0>::type(),
477                typename __make_tuple_types<tuple, 0>::type(),
478                __t...
479               ) {}
480
481    template <class ..._Up,
482              class = typename enable_if
483                      <
484                         sizeof...(_Up) <= sizeof...(_Tp) &&
485                         __tuple_convertible
486                         <
487                            tuple<_Up...>,
488                            typename __make_tuple_types<tuple,
489                                     sizeof...(_Up) < sizeof...(_Tp) ?
490                                        sizeof...(_Up) :
491                                        sizeof...(_Tp)>::type
492                         >::value
493                      >::type
494             >
495        _LIBCPP_INLINE_VISIBILITY
496        explicit
497        tuple(_Up&&... __u)
498            : base_(typename __make_tuple_indices<sizeof...(_Up)>::type(),
499                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
500                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
501                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
502                    _VSTD::forward<_Up>(__u)...) {}
503
504    template <class _Alloc, class ..._Up,
505              class = typename enable_if
506                      <
507                         sizeof...(_Up) <= sizeof...(_Tp) &&
508                         __tuple_convertible
509                         <
510                            tuple<_Up...>,
511                            typename __make_tuple_types<tuple,
512                                     sizeof...(_Up) < sizeof...(_Tp) ?
513                                        sizeof...(_Up) :
514                                        sizeof...(_Tp)>::type
515                         >::value
516                      >::type
517             >
518        _LIBCPP_INLINE_VISIBILITY
519        tuple(allocator_arg_t, const _Alloc& __a, _Up&&... __u)
520            : base_(allocator_arg_t(), __a,
521                    typename __make_tuple_indices<sizeof...(_Up)>::type(),
522                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
523                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
524                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
525                    _VSTD::forward<_Up>(__u)...) {}
526
527    template <class _Tuple,
528              class = typename enable_if
529                      <
530                         __tuple_convertible<_Tuple, tuple>::value
531                      >::type
532             >
533        _LIBCPP_INLINE_VISIBILITY
534        tuple(_Tuple&& __t)
535            : base_(_VSTD::forward<_Tuple>(__t)) {}
536
537    template <class _Alloc, class _Tuple,
538              class = typename enable_if
539                      <
540                         __tuple_convertible<_Tuple, tuple>::value
541                      >::type
542             >
543        _LIBCPP_INLINE_VISIBILITY
544        tuple(allocator_arg_t, const _Alloc& __a, _Tuple&& __t)
545            : base_(allocator_arg_t(), __a, _VSTD::forward<_Tuple>(__t)) {}
546
547    template <class _Tuple,
548              class = typename enable_if
549                      <
550                         __tuple_assignable<_Tuple, tuple>::value
551                      >::type
552             >
553        _LIBCPP_INLINE_VISIBILITY
554        tuple&
555        operator=(_Tuple&& __t)
556        {
557            base_.operator=(_VSTD::forward<_Tuple>(__t));
558            return *this;
559        }
560
561    _LIBCPP_INLINE_VISIBILITY
562    void swap(tuple& __t) _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
563        {base_.swap(__t.base_);}
564};
565
566template <>
567class _LIBCPP_VISIBLE tuple<>
568{
569public:
570    _LIBCPP_INLINE_VISIBILITY
571    tuple() {}
572    template <class _Alloc>
573    _LIBCPP_INLINE_VISIBILITY
574        tuple(allocator_arg_t, const _Alloc&) {}
575    template <class _Alloc>
576    _LIBCPP_INLINE_VISIBILITY
577        tuple(allocator_arg_t, const _Alloc&, const tuple&) {}
578    template <class _U>
579    _LIBCPP_INLINE_VISIBILITY
580        tuple(array<_U, 0>) {}
581    template <class _Alloc, class _U>
582    _LIBCPP_INLINE_VISIBILITY
583        tuple(allocator_arg_t, const _Alloc&, array<_U, 0>) {}
584    _LIBCPP_INLINE_VISIBILITY
585    void swap(tuple&) _NOEXCEPT {}
586};
587
588template <class ..._Tp>
589inline _LIBCPP_INLINE_VISIBILITY
590typename enable_if
591<
592    __all<__is_swappable<_Tp>::value...>::value,
593    void
594>::type
595swap(tuple<_Tp...>& __t, tuple<_Tp...>& __u)
596                 _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value)
597    {__t.swap(__u);}
598
599// get
600
601template <size_t _Ip, class ..._Tp>
602inline _LIBCPP_INLINE_VISIBILITY
603typename tuple_element<_Ip, tuple<_Tp...> >::type&
604get(tuple<_Tp...>& __t)
605{
606    typedef typename tuple_element<_Ip, tuple<_Tp...> >::type type;
607    return static_cast<__tuple_leaf<_Ip, type>&>(__t.base_).get();
608}
609
610template <size_t _Ip, class ..._Tp>
611inline _LIBCPP_INLINE_VISIBILITY
612const typename tuple_element<_Ip, tuple<_Tp...> >::type&
613get(const tuple<_Tp...>& __t)
614{
615    typedef typename tuple_element<_Ip, tuple<_Tp...> >::type type;
616    return static_cast<const __tuple_leaf<_Ip, type>&>(__t.base_).get();
617}
618
619template <size_t _Ip, class ..._Tp>
620inline _LIBCPP_INLINE_VISIBILITY
621typename tuple_element<_Ip, tuple<_Tp...> >::type&&
622get(tuple<_Tp...>&& __t)
623{
624    typedef typename tuple_element<_Ip, tuple<_Tp...> >::type type;
625    return static_cast<type&&>(
626             static_cast<__tuple_leaf<_Ip, type>&&>(__t.base_).get());
627}
628
629// tie
630
631template <class ..._Tp>
632inline _LIBCPP_INLINE_VISIBILITY
633tuple<_Tp&...>
634tie(_Tp&... __t)
635{
636    return tuple<_Tp&...>(__t...);
637}
638
639template <class _Up>
640struct __ignore_t
641{
642    template <class _Tp>
643        _LIBCPP_INLINE_VISIBILITY
644        const __ignore_t& operator=(_Tp&&) const {return *this;}
645};
646
647namespace { const __ignore_t<unsigned char> ignore = __ignore_t<unsigned char>(); }
648
649template <class _Tp> class reference_wrapper;
650
651template <class _Tp>
652struct ___make_tuple_return
653{
654    typedef _Tp type;
655};
656
657template <class _Tp>
658struct ___make_tuple_return<reference_wrapper<_Tp> >
659{
660    typedef _Tp& type;
661};
662
663template <class _Tp>
664struct __make_tuple_return
665{
666    typedef typename ___make_tuple_return<typename decay<_Tp>::type>::type type;
667};
668
669template <class... _Tp>
670inline _LIBCPP_INLINE_VISIBILITY
671tuple<typename __make_tuple_return<_Tp>::type...>
672make_tuple(_Tp&&... __t)
673{
674    return tuple<typename __make_tuple_return<_Tp>::type...>(_VSTD::forward<_Tp>(__t)...);
675}
676
677template <class... _Tp>
678inline _LIBCPP_INLINE_VISIBILITY
679tuple<_Tp&&...>
680forward_as_tuple(_Tp&&... __t)
681{
682    return tuple<_Tp&&...>(_VSTD::forward<_Tp>(__t)...);
683}
684
685template <size_t _I>
686struct __tuple_equal
687{
688    template <class _Tp, class _Up>
689    _LIBCPP_INLINE_VISIBILITY
690    bool operator()(const _Tp& __x, const _Up& __y)
691    {
692        return __tuple_equal<_I - 1>()(__x, __y) && get<_I-1>(__x) == get<_I-1>(__y);
693    }
694};
695
696template <>
697struct __tuple_equal<0>
698{
699    template <class _Tp, class _Up>
700    _LIBCPP_INLINE_VISIBILITY
701    bool operator()(const _Tp&, const _Up&)
702    {
703        return true;
704    }
705};
706
707template <class ..._Tp, class ..._Up>
708inline _LIBCPP_INLINE_VISIBILITY
709bool
710operator==(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
711{
712    return __tuple_equal<sizeof...(_Tp)>()(__x, __y);
713}
714
715template <class ..._Tp, class ..._Up>
716inline _LIBCPP_INLINE_VISIBILITY
717bool
718operator!=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
719{
720    return !(__x == __y);
721}
722
723template <size_t _I>
724struct __tuple_less
725{
726    template <class _Tp, class _Up>
727    _LIBCPP_INLINE_VISIBILITY
728    bool operator()(const _Tp& __x, const _Up& __y)
729    {
730        return __tuple_less<_I-1>()(__x, __y) ||
731             (!__tuple_less<_I-1>()(__y, __x) && get<_I-1>(__x) < get<_I-1>(__y));
732    }
733};
734
735template <>
736struct __tuple_less<0>
737{
738    template <class _Tp, class _Up>
739    _LIBCPP_INLINE_VISIBILITY
740    bool operator()(const _Tp&, const _Up&)
741    {
742        return false;
743    }
744};
745
746template <class ..._Tp, class ..._Up>
747inline _LIBCPP_INLINE_VISIBILITY
748bool
749operator<(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
750{
751    return __tuple_less<sizeof...(_Tp)>()(__x, __y);
752}
753
754template <class ..._Tp, class ..._Up>
755inline _LIBCPP_INLINE_VISIBILITY
756bool
757operator>(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
758{
759    return __y < __x;
760}
761
762template <class ..._Tp, class ..._Up>
763inline _LIBCPP_INLINE_VISIBILITY
764bool
765operator>=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
766{
767    return !(__x < __y);
768}
769
770template <class ..._Tp, class ..._Up>
771inline _LIBCPP_INLINE_VISIBILITY
772bool
773operator<=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
774{
775    return !(__y < __x);
776}
777
778// tuple_cat
779
780template <class _Tp, class _Up> struct __tuple_cat_type;
781
782template <class ..._Ttypes, class ..._Utypes>
783struct __tuple_cat_type<tuple<_Ttypes...>, __tuple_types<_Utypes...> >
784{
785    typedef tuple<_Ttypes..., _Utypes...> type;
786};
787
788template <class _ResultTuple, bool _Is_Tuple0TupleLike, class ..._Tuples>
789struct __tuple_cat_return_1
790{
791};
792
793template <class ..._Types, class _Tuple0>
794struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0>
795{
796    typedef typename __tuple_cat_type<tuple<_Types...>,
797            typename __make_tuple_types<typename remove_reference<_Tuple0>::type>::type>::type
798                                                                           type;
799};
800
801template <class ..._Types, class _Tuple0, class _Tuple1, class ..._Tuples>
802struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0, _Tuple1, _Tuples...>
803    : public __tuple_cat_return_1<
804                 typename __tuple_cat_type<
805                     tuple<_Types...>,
806                     typename __make_tuple_types<typename remove_reference<_Tuple0>::type>::type
807                 >::type,
808                 __tuple_like<typename remove_reference<_Tuple1>::type>::value,
809                 _Tuple1, _Tuples...>
810{
811};
812
813template <class ..._Tuples> struct __tuple_cat_return;
814
815template <class _Tuple0, class ..._Tuples>
816struct __tuple_cat_return<_Tuple0, _Tuples...>
817    : public __tuple_cat_return_1<tuple<>,
818         __tuple_like<typename remove_reference<_Tuple0>::type>::value, _Tuple0,
819                                                                     _Tuples...>
820{
821};
822
823template <>
824struct __tuple_cat_return<>
825{
826    typedef tuple<> type;
827};
828
829inline _LIBCPP_INLINE_VISIBILITY
830tuple<>
831tuple_cat()
832{
833    return tuple<>();
834}
835
836template <class _R, class _Indices, class _Tuple0, class ..._Tuples>
837struct __tuple_cat_return_ref_imp;
838
839template <class ..._Types, size_t ..._I0, class _Tuple0>
840struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>, _Tuple0>
841{
842    typedef typename remove_reference<_Tuple0>::type _T0;
843    typedef tuple<_Types..., typename __apply_cv<_Tuple0,
844                          typename tuple_element<_I0, _T0>::type>::type&&...> type;
845};
846
847template <class ..._Types, size_t ..._I0, class _Tuple0, class _Tuple1, class ..._Tuples>
848struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>,
849                                  _Tuple0, _Tuple1, _Tuples...>
850    : public __tuple_cat_return_ref_imp<
851         tuple<_Types..., typename __apply_cv<_Tuple0,
852               typename tuple_element<_I0,
853                  typename remove_reference<_Tuple0>::type>::type>::type&&...>,
854         typename __make_tuple_indices<tuple_size<typename
855                                 remove_reference<_Tuple1>::type>::value>::type,
856         _Tuple1, _Tuples...>
857{
858};
859
860template <class _Tuple0, class ..._Tuples>
861struct __tuple_cat_return_ref
862    : public __tuple_cat_return_ref_imp<tuple<>,
863               typename __make_tuple_indices<
864                        tuple_size<typename remove_reference<_Tuple0>::type>::value
865               >::type, _Tuple0, _Tuples...>
866{
867};
868
869template <class _Types, class _I0, class _J0>
870struct __tuple_cat;
871
872template <class ..._Types, size_t ..._I0, size_t ..._J0>
873struct __tuple_cat<tuple<_Types...>, __tuple_indices<_I0...>, __tuple_indices<_J0...> >
874{
875    template <class _Tuple0>
876    _LIBCPP_INLINE_VISIBILITY
877    typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&>::type
878    operator()(tuple<_Types...> __t, _Tuple0&& __t0)
879    {
880        return _VSTD::forward_as_tuple(_VSTD::forward<_Types>(get<_I0>(__t))...,
881                                      get<_J0>(_VSTD::forward<_Tuple0>(__t0))...);
882    }
883
884    template <class _Tuple0, class _Tuple1, class ..._Tuples>
885    _LIBCPP_INLINE_VISIBILITY
886    typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&, _Tuple1&&, _Tuples&&...>::type
887    operator()(tuple<_Types...> __t, _Tuple0&& __t0, _Tuple1&& __t1, _Tuples&& ...__tpls)
888    {
889        typedef typename remove_reference<_Tuple0>::type _T0;
890        typedef typename remove_reference<_Tuple1>::type _T1;
891        return __tuple_cat<
892           tuple<_Types..., typename __apply_cv<_Tuple0, typename tuple_element<_J0, _T0>::type>::type&&...>,
893           typename __make_tuple_indices<sizeof ...(_Types) + tuple_size<_T0>::value>::type,
894           typename __make_tuple_indices<tuple_size<_T1>::value>::type>()
895                           (_VSTD::forward_as_tuple(
896                              _VSTD::forward<_Types>(get<_I0>(__t))...,
897                              get<_J0>(_VSTD::forward<_Tuple0>(__t0))...
898                            ),
899                            _VSTD::forward<_Tuple1>(__t1),
900                            _VSTD::forward<_Tuples>(__tpls)...);
901    }
902};
903
904template <class _Tuple0, class... _Tuples>
905inline _LIBCPP_INLINE_VISIBILITY
906typename __tuple_cat_return<_Tuple0, _Tuples...>::type
907tuple_cat(_Tuple0&& __t0, _Tuples&&... __tpls)
908{
909    typedef typename remove_reference<_Tuple0>::type _T0;
910    return __tuple_cat<tuple<>, __tuple_indices<>,
911                  typename __make_tuple_indices<tuple_size<_T0>::value>::type>()
912                  (tuple<>(), _VSTD::forward<_Tuple0>(__t0),
913                                            _VSTD::forward<_Tuples>(__tpls)...);
914}
915
916template <class ..._Tp, class _Alloc>
917struct _LIBCPP_VISIBLE uses_allocator<tuple<_Tp...>, _Alloc>
918    : true_type {};
919
920template <class _T1, class _T2>
921template <class... _Args1, class... _Args2, size_t ..._I1, size_t ..._I2>
922inline _LIBCPP_INLINE_VISIBILITY
923pair<_T1, _T2>::pair(piecewise_construct_t,
924                     tuple<_Args1...>& __first_args, tuple<_Args2...>& __second_args,
925                     __tuple_indices<_I1...>, __tuple_indices<_I2...>)
926    :  first(_VSTD::forward<_Args1>(get<_I1>( __first_args))...),
927      second(_VSTD::forward<_Args2>(get<_I2>(__second_args))...)
928{
929}
930
931#endif  // _LIBCPP_HAS_NO_VARIADICS
932
933_LIBCPP_END_NAMESPACE_STD
934
935#endif  // _LIBCPP_TUPLE
936