xref: /llvm-project-15.0.7/libcxx/include/tuple (revision a462f5cc)
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&&);
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& operator=(tuple&&);
60    template <class... U>
61        tuple& operator=(const tuple<U...>&);
62    template <class... U>
63        tuple& operator=(tuple<U...>&&);
64    template <class U1, class U2>
65        tuple& operator=(const pair<U1, U2>&); // iff sizeof...(T) == 2
66    template <class U1, class U2>
67        tuple& operator=(pair<U1, U2>&&); //iffsizeof...(T) == 2
68
69    void swap(tuple&);
70};
71
72const unspecified ignore;
73
74template <class... T> tuple<V...>  make_tuple(T&&...);
75template <class... T> tuple<ATypes...> forward_as_tuple(T&&...);
76template <class... T> tuple<T&...> tie(T&...);
77template <class... Tuples> tuple<CTypes...> tuple_cat(Tuples&&... tpls);
78
79// 20.4.1.4, tuple helper classes:
80template <class T> class tuple_size; // undefined
81template <class... T> class tuple_size<tuple<T...>>;
82template <intsize_t I, class T> class tuple_element; // undefined
83template <intsize_t I, class... T> class tuple_element<I, tuple<T...>>;
84
85// 20.4.1.5, element access:
86template <intsize_t I, class... T> typename tuple_element<I, tuple<T...>>::type& get(tuple<T...>&);
87template <intsize_t I, class... T> typename tuple_element<I, tuple<T...>>::type const& get(const tuple<T...>&);
88template <intsize_t I, class... T> typename tuple_element<I, tuple<T...>>::type&& get(tuple<T...>&&);
89
90// 20.4.1.6, relational operators:
91template<class... T, class... U> bool operator==(const tuple<T...>&, const tuple<U...>&);
92template<class... T, class... U> bool operator<(const tuple<T...>&, const tuple<U...>&);
93template<class... T, class... U> bool operator!=(const tuple<T...>&, const tuple<U...>&);
94template<class... T, class... U> bool operator>(const tuple<T...>&, const tuple<U...>&);
95template<class... T, class... U> bool operator<=(const tuple<T...>&, const tuple<U...>&);
96template<class... T, class... U> bool operator>=(const tuple<T...>&, const tuple<U...>&);
97
98template <class... Types, class Alloc>
99  struct uses_allocator<tuple<Types...>, Alloc>;
100
101template <class... Types>
102  void swap(tuple<Types...>& x, tuple<Types...>& y);
103
104}  // std
105
106*/
107
108#include <__config>
109#include <__tuple>
110#include <cstddef>
111#include <memory>
112#include <type_traits>
113
114#pragma GCC system_header
115
116_LIBCPP_BEGIN_NAMESPACE_STD
117
118#ifndef _LIBCPP_HAS_NO_VARIADICS
119
120// tuple_size
121
122template <class ..._Tp>
123class _LIBCPP_VISIBLE tuple_size<tuple<_Tp...> >
124    : public integral_constant<size_t, sizeof...(_Tp)>
125{
126};
127
128// tuple_element
129
130template <size_t _Ip, class ..._Tp>
131class _LIBCPP_VISIBLE tuple_element<_Ip, tuple<_Tp...> >
132{
133public:
134    typedef typename tuple_element<_Ip, __tuple_types<_Tp...> >::type type;
135};
136
137// __tuple_leaf
138
139template <size_t _Ip, class _Hp, bool=is_empty<_Hp>::value>
140class __tuple_leaf;
141
142template <size_t _Ip, class _Hp, bool _Ep>
143inline _LIBCPP_INLINE_VISIBILITY
144void swap(__tuple_leaf<_Ip, _Hp, _Ep>& __x, __tuple_leaf<_Ip, _Hp, _Ep>& __y)
145{
146    swap(__x.get(), __y.get());
147}
148
149template <size_t _Ip, class _Hp, bool>
150class __tuple_leaf
151{
152    _Hp value;
153
154    __tuple_leaf& operator=(const __tuple_leaf&);
155public:
156    _LIBCPP_INLINE_VISIBILITY __tuple_leaf() : value()
157       {static_assert(!is_reference<_Hp>::value,
158              "Attempted to default construct a reference element in a tuple");}
159
160    template <class _Alloc>
161        _LIBCPP_INLINE_VISIBILITY
162        __tuple_leaf(integral_constant<int, 0>, const _Alloc&)
163            : value()
164        {static_assert(!is_reference<_Hp>::value,
165              "Attempted to default construct a reference element in a tuple");}
166
167    template <class _Alloc>
168        _LIBCPP_INLINE_VISIBILITY
169        __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a)
170            : value(allocator_arg_t(), __a)
171        {static_assert(!is_reference<_Hp>::value,
172              "Attempted to default construct a reference element in a tuple");}
173
174    template <class _Alloc>
175        _LIBCPP_INLINE_VISIBILITY
176        __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a)
177            : value(__a)
178        {static_assert(!is_reference<_Hp>::value,
179              "Attempted to default construct a reference element in a tuple");}
180
181    template <class _Tp,
182              class = typename enable_if<is_constructible<_Hp, _Tp>::value>::type>
183        _LIBCPP_INLINE_VISIBILITY
184        explicit __tuple_leaf(_Tp&& __t)
185            : value(_STD::forward<_Tp>(__t))
186        {static_assert(!is_reference<_Hp>::value ||
187                        is_lvalue_reference<_Hp>::value &&
188                        (is_lvalue_reference<_Tp>::value ||
189                         is_same<typename remove_reference<_Tp>::type,
190                                 reference_wrapper<
191                                    typename remove_reference<_Hp>::type
192                                 >
193                                >::value) ||
194                        (is_rvalue_reference<_Hp>::value &&
195                         !is_lvalue_reference<_Tp>::value),
196       "Attempted to construct a reference element in a tuple with an rvalue");}
197
198    template <class _Tp, class _Alloc>
199        _LIBCPP_INLINE_VISIBILITY
200        explicit __tuple_leaf(integral_constant<int, 0>, const _Alloc&, _Tp&& __t)
201            : value(_STD::forward<_Tp>(__t))
202        {static_assert(!is_lvalue_reference<_Hp>::value ||
203                        is_lvalue_reference<_Hp>::value &&
204                        (is_lvalue_reference<_Tp>::value ||
205                         is_same<typename remove_reference<_Tp>::type,
206                                 reference_wrapper<
207                                    typename remove_reference<_Hp>::type
208                                 >
209                                >::value),
210       "Attempted to construct a reference element in a tuple with an rvalue");}
211
212    template <class _Tp, class _Alloc>
213        _LIBCPP_INLINE_VISIBILITY
214        explicit __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a, _Tp&& __t)
215            : value(allocator_arg_t(), __a, _STD::forward<_Tp>(__t))
216        {static_assert(!is_lvalue_reference<_Hp>::value ||
217                        is_lvalue_reference<_Hp>::value &&
218                        (is_lvalue_reference<_Tp>::value ||
219                         is_same<typename remove_reference<_Tp>::type,
220                                 reference_wrapper<
221                                    typename remove_reference<_Hp>::type
222                                 >
223                                >::value),
224       "Attempted to construct a reference element in a tuple with an rvalue");}
225
226    template <class _Tp, class _Alloc>
227        _LIBCPP_INLINE_VISIBILITY
228        explicit __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a, _Tp&& __t)
229            : value(_STD::forward<_Tp>(__t), __a)
230        {static_assert(!is_lvalue_reference<_Hp>::value ||
231                        is_lvalue_reference<_Hp>::value &&
232                        (is_lvalue_reference<_Tp>::value ||
233                         is_same<typename remove_reference<_Tp>::type,
234                                 reference_wrapper<
235                                    typename remove_reference<_Hp>::type
236                                 >
237                                >::value),
238       "Attempted to construct a reference element in a tuple with an rvalue");}
239
240    __tuple_leaf(const __tuple_leaf& __t)
241        : value(__t.get())
242        {static_assert(!is_rvalue_reference<_Hp>::value, "Can not copy a tuple with rvalue reference member");}
243
244    template <class _Tp>
245        _LIBCPP_INLINE_VISIBILITY
246        explicit __tuple_leaf(const __tuple_leaf<_Ip, _Tp>& __t)
247            : value(__t.get()) {}
248
249    template <class _Tp>
250        _LIBCPP_INLINE_VISIBILITY
251        __tuple_leaf&
252        operator=(_Tp&& __t)
253        {
254            value = _STD::forward<_Tp>(__t);
255            return *this;
256        }
257
258    _LIBCPP_INLINE_VISIBILITY
259    int swap(__tuple_leaf& __t)
260    {
261        _STD::swap(*this, __t);
262        return 0;
263    }
264
265    _LIBCPP_INLINE_VISIBILITY       _Hp& get()       {return value;}
266    _LIBCPP_INLINE_VISIBILITY const _Hp& get() const {return value;}
267};
268
269template <size_t _Ip, class _Hp>
270class __tuple_leaf<_Ip, _Hp, true>
271    : private _Hp
272{
273
274    __tuple_leaf& operator=(const __tuple_leaf&);
275public:
276    _LIBCPP_INLINE_VISIBILITY __tuple_leaf() {}
277
278    template <class _Alloc>
279        _LIBCPP_INLINE_VISIBILITY
280        __tuple_leaf(integral_constant<int, 0>, const _Alloc&) {}
281
282    template <class _Alloc>
283        _LIBCPP_INLINE_VISIBILITY
284        __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a)
285            : _Hp(allocator_arg_t(), __a) {}
286
287    template <class _Alloc>
288        _LIBCPP_INLINE_VISIBILITY
289        __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a)
290            : _Hp(__a) {}
291
292    template <class _Tp,
293              class = typename enable_if<is_constructible<_Hp, _Tp>::value>::type>
294        _LIBCPP_INLINE_VISIBILITY
295        explicit __tuple_leaf(_Tp&& __t)
296            : _Hp(_STD::forward<_Tp>(__t)) {}
297
298    template <class _Tp, class _Alloc>
299        _LIBCPP_INLINE_VISIBILITY
300        explicit __tuple_leaf(integral_constant<int, 0>, const _Alloc&, _Tp&& __t)
301            : _Hp(_STD::forward<_Tp>(__t)) {}
302
303    template <class _Tp, class _Alloc>
304        _LIBCPP_INLINE_VISIBILITY
305        explicit __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a, _Tp&& __t)
306            : _Hp(allocator_arg_t(), __a, _STD::forward<_Tp>(__t)) {}
307
308    template <class _Tp, class _Alloc>
309        _LIBCPP_INLINE_VISIBILITY
310        explicit __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a, _Tp&& __t)
311            : _Hp(_STD::forward<_Tp>(__t), __a) {}
312
313    template <class _Tp>
314        _LIBCPP_INLINE_VISIBILITY
315        explicit __tuple_leaf(const __tuple_leaf<_Ip, _Tp>& __t)
316            : _Hp(__t.get()) {}
317
318    template <class _Tp>
319        _LIBCPP_INLINE_VISIBILITY
320        __tuple_leaf&
321        operator=(_Tp&& __t)
322        {
323            _Hp::operator=(_STD::forward<_Tp>(__t));
324            return *this;
325        }
326
327    _LIBCPP_INLINE_VISIBILITY int swap(__tuple_leaf& __t)
328    {
329        _STD::swap(*this, __t);
330        return 0;
331    }
332
333    _LIBCPP_INLINE_VISIBILITY       _Hp& get()       {return static_cast<_Hp&>(*this);}
334    _LIBCPP_INLINE_VISIBILITY const _Hp& get() const {return static_cast<const _Hp&>(*this);}
335};
336
337template <class ..._Tp>
338_LIBCPP_INLINE_VISIBILITY
339void __swallow(_Tp&&...) {}
340
341// __tuple_impl
342
343template<class _Indx, class ..._Tp> struct __tuple_impl;
344
345template<size_t ..._Indx, class ..._Tp>
346struct __tuple_impl<__tuple_indices<_Indx...>, _Tp...>
347    : public __tuple_leaf<_Indx, _Tp>...
348{
349    template <size_t ..._Uf, class ..._Tf,
350              size_t ..._Ul, class ..._Tl, class ..._Up>
351        _LIBCPP_INLINE_VISIBILITY
352        explicit
353        __tuple_impl(__tuple_indices<_Uf...>, __tuple_types<_Tf...>,
354                     __tuple_indices<_Ul...>, __tuple_types<_Tl...>,
355                     _Up&&... __u) :
356            __tuple_leaf<_Uf, _Tf>(_STD::forward<_Up>(__u))...,
357            __tuple_leaf<_Ul, _Tl>()...
358            {}
359
360    template <class _Alloc, size_t ..._Uf, class ..._Tf,
361              size_t ..._Ul, class ..._Tl, class ..._Up>
362        _LIBCPP_INLINE_VISIBILITY
363        explicit
364        __tuple_impl(allocator_arg_t, const _Alloc& __a,
365                     __tuple_indices<_Uf...>, __tuple_types<_Tf...>,
366                     __tuple_indices<_Ul...>, __tuple_types<_Tl...>,
367                     _Up&&... __u) :
368            __tuple_leaf<_Uf, _Tf>(__uses_alloc_ctor<_Tf, _Alloc, _Up>(), __a,
369            _STD::forward<_Up>(__u))...,
370            __tuple_leaf<_Ul, _Tl>(__uses_alloc_ctor<_Tl, _Alloc>(), __a)...
371            {}
372
373    template <class _Tuple,
374              class = typename enable_if
375                      <
376                         __tuple_convertible<_Tuple, tuple<_Tp...> >::value
377                      >::type
378             >
379        _LIBCPP_INLINE_VISIBILITY
380        __tuple_impl(_Tuple&& __t)
381            : __tuple_leaf<_Indx, _Tp>(_STD::forward<typename tuple_element<_Indx,
382                                       typename __make_tuple_types<_Tuple>::type>::type>(_STD::get<_Indx>(__t)))...
383            {}
384
385    template <class _Alloc, class _Tuple,
386              class = typename enable_if
387                      <
388                         __tuple_convertible<_Tuple, tuple<_Tp...> >::value
389                      >::type
390             >
391        _LIBCPP_INLINE_VISIBILITY
392        __tuple_impl(allocator_arg_t, const _Alloc& __a, _Tuple&& __t)
393            : __tuple_leaf<_Indx, _Tp>(__uses_alloc_ctor<_Tp, _Alloc, typename tuple_element<_Indx,
394                                       typename __make_tuple_types<_Tuple>::type>::type>(), __a,
395                                       _STD::forward<typename tuple_element<_Indx,
396                                       typename __make_tuple_types<_Tuple>::type>::type>(_STD::get<_Indx>(__t)))...
397            {}
398
399    template <class _Tuple>
400        _LIBCPP_INLINE_VISIBILITY
401        typename enable_if
402        <
403            __tuple_assignable<_Tuple, tuple<_Tp...> >::value,
404            __tuple_impl&
405        >::type
406        operator=(_Tuple&& __t)
407        {
408            __swallow(__tuple_leaf<_Indx, _Tp>::operator=(_STD::forward<typename tuple_element<_Indx,
409                                       typename __make_tuple_types<_Tuple>::type>::type>(_STD::get<_Indx>(__t)))...);
410            return *this;
411        }
412
413    _LIBCPP_INLINE_VISIBILITY
414    void swap(__tuple_impl& __t)
415    {
416        __swallow(__tuple_leaf<_Indx, _Tp>::swap(static_cast<__tuple_leaf<_Indx, _Tp>&>(__t))...);
417    }
418};
419
420template <class ..._Tp>
421class _LIBCPP_VISIBLE tuple
422{
423    typedef __tuple_impl<typename __make_tuple_indices<sizeof...(_Tp)>::type, _Tp...> base;
424
425    base base_;
426
427    template <size_t _Jp, class ..._Up> friend
428        typename tuple_element<_Jp, tuple<_Up...> >::type& get(tuple<_Up...>&);
429    template <size_t _Jp, class ..._Up> friend
430        const typename tuple_element<_Jp, tuple<_Up...> >::type& get(const tuple<_Up...>&);
431    template <size_t _Jp, class ..._Up> friend
432        typename tuple_element<_Jp, tuple<_Up...> >::type&& get(tuple<_Up...>&&);
433public:
434
435    _LIBCPP_INLINE_VISIBILITY
436    explicit tuple(const _Tp& ... __t)
437        : base_(typename __make_tuple_indices<sizeof...(_Tp)>::type(),
438                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
439                typename __make_tuple_indices<0>::type(),
440                typename __make_tuple_types<tuple, 0>::type(),
441                __t...
442               ) {}
443
444    template <class _Alloc>
445      _LIBCPP_INLINE_VISIBILITY
446      tuple(allocator_arg_t, const _Alloc& __a, const _Tp& ... __t)
447        : base_(allocator_arg_t(), __a,
448                typename __make_tuple_indices<sizeof...(_Tp)>::type(),
449                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
450                typename __make_tuple_indices<0>::type(),
451                typename __make_tuple_types<tuple, 0>::type(),
452                __t...
453               ) {}
454
455    template <class ..._Up,
456              class = typename enable_if
457                      <
458                         sizeof...(_Up) <= sizeof...(_Tp) &&
459                         __tuple_convertible
460                         <
461                            tuple<_Up...>,
462                            typename __make_tuple_types<tuple,
463                                     sizeof...(_Up) < sizeof...(_Tp) ?
464                                        sizeof...(_Up) :
465                                        sizeof...(_Tp)>::type
466                         >::value
467                      >::type
468             >
469        _LIBCPP_INLINE_VISIBILITY
470        explicit
471        tuple(_Up&&... __u)
472            : base_(typename __make_tuple_indices<sizeof...(_Up)>::type(),
473                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
474                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
475                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
476                    _STD::forward<_Up>(__u)...) {}
477
478    template <class _Alloc, class ..._Up,
479              class = typename enable_if
480                      <
481                         sizeof...(_Up) <= sizeof...(_Tp) &&
482                         __tuple_convertible
483                         <
484                            tuple<_Up...>,
485                            typename __make_tuple_types<tuple,
486                                     sizeof...(_Up) < sizeof...(_Tp) ?
487                                        sizeof...(_Up) :
488                                        sizeof...(_Tp)>::type
489                         >::value
490                      >::type
491             >
492        _LIBCPP_INLINE_VISIBILITY
493        tuple(allocator_arg_t, const _Alloc& __a, _Up&&... __u)
494            : base_(allocator_arg_t(), __a,
495                    typename __make_tuple_indices<sizeof...(_Up)>::type(),
496                    typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
497                    typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
498                    typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
499                    _STD::forward<_Up>(__u)...) {}
500
501    template <class _Tuple,
502              class = typename enable_if
503                      <
504                         __tuple_convertible<_Tuple, tuple>::value
505                      >::type
506             >
507        _LIBCPP_INLINE_VISIBILITY
508        tuple(_Tuple&& __t)
509            : base_(_STD::forward<_Tuple>(__t)) {}
510
511    template <class _Alloc, class _Tuple,
512              class = typename enable_if
513                      <
514                         __tuple_convertible<_Tuple, tuple>::value
515                      >::type
516             >
517        _LIBCPP_INLINE_VISIBILITY
518        tuple(allocator_arg_t, const _Alloc& __a, _Tuple&& __t)
519            : base_(allocator_arg_t(), __a, _STD::forward<_Tuple>(__t)) {}
520
521    template <class _Tuple,
522              class = typename enable_if
523                      <
524                         __tuple_assignable<_Tuple, tuple>::value
525                      >::type
526             >
527        _LIBCPP_INLINE_VISIBILITY
528        tuple&
529        operator=(_Tuple&& __t)
530        {
531            base_.operator=(_STD::forward<_Tuple>(__t));
532            return *this;
533        }
534
535    _LIBCPP_INLINE_VISIBILITY
536    void swap(tuple& __t) {base_.swap(__t.base_);}
537};
538
539template <>
540class _LIBCPP_VISIBLE tuple<>
541{
542public:
543    _LIBCPP_INLINE_VISIBILITY
544    tuple() {}
545    template <class _Alloc>
546    _LIBCPP_INLINE_VISIBILITY
547        tuple(allocator_arg_t, const _Alloc&) {}
548    template <class _Alloc>
549    _LIBCPP_INLINE_VISIBILITY
550        tuple(allocator_arg_t, const _Alloc&, const tuple&) {}
551    template <class _U>
552    _LIBCPP_INLINE_VISIBILITY
553        tuple(array<_U, 0>) {}
554    template <class _Alloc, class _U>
555    _LIBCPP_INLINE_VISIBILITY
556        tuple(allocator_arg_t, const _Alloc&, array<_U, 0>) {}
557    _LIBCPP_INLINE_VISIBILITY
558    void swap(tuple&) {}
559};
560
561template <class ..._Tp>
562inline _LIBCPP_INLINE_VISIBILITY
563void
564swap(tuple<_Tp...>& __t, tuple<_Tp...>& __u) {__t.swap(__u);}
565
566// get
567
568template <size_t _Ip, class ..._Tp>
569inline _LIBCPP_INLINE_VISIBILITY
570typename tuple_element<_Ip, tuple<_Tp...> >::type&
571get(tuple<_Tp...>& __t)
572{
573    typedef typename tuple_element<_Ip, tuple<_Tp...> >::type type;
574    return static_cast<__tuple_leaf<_Ip, type>&>(__t.base_).get();
575}
576
577template <size_t _Ip, class ..._Tp>
578inline _LIBCPP_INLINE_VISIBILITY
579const typename tuple_element<_Ip, tuple<_Tp...> >::type&
580get(const tuple<_Tp...>& __t)
581{
582    typedef typename tuple_element<_Ip, tuple<_Tp...> >::type type;
583    return static_cast<const __tuple_leaf<_Ip, type>&>(__t.base_).get();
584}
585
586template <size_t _Ip, class ..._Tp>
587inline _LIBCPP_INLINE_VISIBILITY
588typename tuple_element<_Ip, tuple<_Tp...> >::type&&
589get(tuple<_Tp...>&& __t)
590{
591    typedef typename tuple_element<_Ip, tuple<_Tp...> >::type type;
592    return static_cast<type&&>(
593             static_cast<__tuple_leaf<_Ip, type>&&>(__t.base_).get());
594}
595
596// tie
597
598template <class ..._Tp>
599inline _LIBCPP_INLINE_VISIBILITY
600tuple<_Tp&...>
601tie(_Tp&... __t)
602{
603    return tuple<_Tp&...>(__t...);
604}
605
606template <class _Up>
607struct __ignore_t
608{
609    _LIBCPP_INLINE_VISIBILITY
610    __ignore_t() {}
611    template <class _Tp>
612        _LIBCPP_INLINE_VISIBILITY
613        __ignore_t(_Tp&&) {}
614    template <class _Tp>
615        _LIBCPP_INLINE_VISIBILITY
616        const __ignore_t& operator=(_Tp&&) const {return *this;}
617};
618
619namespace { const __ignore_t<unsigned char> ignore = __ignore_t<unsigned char>(); }
620
621template <class _Tp> class reference_wrapper;
622
623template <class _Tp>
624struct ___make_tuple_return
625{
626    typedef _Tp type;
627};
628
629template <class _Tp>
630struct ___make_tuple_return<reference_wrapper<_Tp> >
631{
632    typedef _Tp& type;
633};
634
635template <class _Tp>
636struct __make_tuple_return
637{
638    typedef typename ___make_tuple_return<typename decay<_Tp>::type>::type type;
639};
640
641template <class... _Tp>
642inline _LIBCPP_INLINE_VISIBILITY
643tuple<typename __make_tuple_return<_Tp>::type...>
644make_tuple(_Tp&&... __t)
645{
646    return tuple<typename __make_tuple_return<_Tp>::type...>(_STD::forward<_Tp>(__t)...);
647}
648
649template <class... _Tp>
650inline _LIBCPP_INLINE_VISIBILITY
651tuple<_Tp&&...>
652forward_as_tuple(_Tp&&... __t)
653{
654    return tuple<_Tp&&...>(_STD::forward<_Tp>(__t)...);
655}
656
657template <size_t _I>
658struct __tuple_equal
659{
660    template <class _Tp, class _Up>
661    _LIBCPP_INLINE_VISIBILITY
662    bool operator()(const _Tp& __x, const _Up& __y)
663    {
664        return __tuple_equal<_I - 1>()(__x, __y) && get<_I-1>(__x) == get<_I-1>(__y);
665    }
666};
667
668template <>
669struct __tuple_equal<0>
670{
671    template <class _Tp, class _Up>
672    _LIBCPP_INLINE_VISIBILITY
673    bool operator()(const _Tp&, const _Up&)
674    {
675        return true;
676    }
677};
678
679template <class ..._Tp, class ..._Up>
680inline _LIBCPP_INLINE_VISIBILITY
681bool
682operator==(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
683{
684    return __tuple_equal<sizeof...(_Tp)>()(__x, __y);
685}
686
687template <class ..._Tp, class ..._Up>
688inline _LIBCPP_INLINE_VISIBILITY
689bool
690operator!=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
691{
692    return !(__x == __y);
693}
694
695template <size_t _I>
696struct __tuple_less
697{
698    template <class _Tp, class _Up>
699    _LIBCPP_INLINE_VISIBILITY
700    bool operator()(const _Tp& __x, const _Up& __y)
701    {
702        return __tuple_less<_I-1>()(__x, __y) ||
703             (!__tuple_less<_I-1>()(__y, __x) && get<_I-1>(__x) < get<_I-1>(__y));
704    }
705};
706
707template <>
708struct __tuple_less<0>
709{
710    template <class _Tp, class _Up>
711    _LIBCPP_INLINE_VISIBILITY
712    bool operator()(const _Tp&, const _Up&)
713    {
714        return false;
715    }
716};
717
718template <class ..._Tp, class ..._Up>
719inline _LIBCPP_INLINE_VISIBILITY
720bool
721operator<(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
722{
723    return __tuple_less<sizeof...(_Tp)>()(__x, __y);
724}
725
726template <class ..._Tp, class ..._Up>
727inline _LIBCPP_INLINE_VISIBILITY
728bool
729operator>(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
730{
731    return __y < __x;
732}
733
734template <class ..._Tp, class ..._Up>
735inline _LIBCPP_INLINE_VISIBILITY
736bool
737operator>=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
738{
739    return !(__x < __y);
740}
741
742template <class ..._Tp, class ..._Up>
743inline _LIBCPP_INLINE_VISIBILITY
744bool
745operator<=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y)
746{
747    return !(__y < __x);
748}
749
750// tuple_cat
751
752template <class _Tp, class _Up> struct __tuple_cat_type;
753
754template <class ..._Ttypes, class ..._Utypes>
755struct __tuple_cat_type<tuple<_Ttypes...>, __tuple_types<_Utypes...> >
756{
757    typedef tuple<_Ttypes..., _Utypes...> type;
758};
759
760template <class _ResultTuple, bool _Is_Tuple0TupleLike, class ..._Tuples>
761struct __tuple_cat_return_1
762{
763};
764
765template <class ..._Types, class _Tuple0>
766struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0>
767{
768    typedef typename __tuple_cat_type<tuple<_Types...>,
769            typename __make_tuple_types<typename remove_reference<_Tuple0>::type>::type>::type
770                                                                           type;
771};
772
773template <class ..._Types, class _Tuple0, class _Tuple1, class ..._Tuples>
774struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0, _Tuple1, _Tuples...>
775    : public __tuple_cat_return_1<
776                 typename __tuple_cat_type<
777                     tuple<_Types...>,
778                     typename __make_tuple_types<typename remove_reference<_Tuple0>::type>::type
779                 >::type,
780                 __tuple_like<typename remove_reference<_Tuple1>::type>::value,
781                 _Tuple1, _Tuples...>
782{
783};
784
785template <class ..._Tuples> struct __tuple_cat_return;
786
787template <class _Tuple0, class ..._Tuples>
788struct __tuple_cat_return<_Tuple0, _Tuples...>
789    : public __tuple_cat_return_1<tuple<>,
790         __tuple_like<typename remove_reference<_Tuple0>::type>::value, _Tuple0,
791                                                                     _Tuples...>
792{
793};
794
795template <>
796struct __tuple_cat_return<>
797{
798    typedef tuple<> type;
799};
800
801inline _LIBCPP_INLINE_VISIBILITY
802tuple<>
803tuple_cat()
804{
805    return tuple<>();
806}
807
808template <class _R, class _Indices, class _Tuple0, class ..._Tuples>
809struct __tuple_cat_return_ref_imp;
810
811template <class ..._Types, size_t ..._I0, class _Tuple0>
812struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>, _Tuple0>
813{
814    typedef typename remove_reference<_Tuple0>::type _T0;
815    typedef tuple<_Types..., typename __apply_cv<_Tuple0,
816                          typename tuple_element<_I0, _T0>::type>::type&&...> type;
817};
818
819template <class ..._Types, size_t ..._I0, class _Tuple0, class _Tuple1, class ..._Tuples>
820struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>,
821                                  _Tuple0, _Tuple1, _Tuples...>
822    : public __tuple_cat_return_ref_imp<
823         tuple<_Types..., typename __apply_cv<_Tuple0,
824               typename tuple_element<_I0,
825                  typename remove_reference<_Tuple0>::type>::type>::type&&...>,
826         typename __make_tuple_indices<tuple_size<typename
827                                 remove_reference<_Tuple1>::type>::value>::type,
828         _Tuple1, _Tuples...>
829{
830};
831
832template <class _Tuple0, class ..._Tuples>
833struct __tuple_cat_return_ref
834    : public __tuple_cat_return_ref_imp<tuple<>,
835               typename __make_tuple_indices<
836                        tuple_size<typename remove_reference<_Tuple0>::type>::value
837               >::type, _Tuple0, _Tuples...>
838{
839};
840
841template <class _Types, class _I0, class _J0>
842struct __tuple_cat;
843
844template <class ..._Types, size_t ..._I0, size_t ..._J0>
845struct __tuple_cat<tuple<_Types...>, __tuple_indices<_I0...>, __tuple_indices<_J0...> >
846{
847    template <class _Tuple0>
848    _LIBCPP_INLINE_VISIBILITY
849    typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&>::type
850    operator()(tuple<_Types...> __t, _Tuple0&& __t0)
851    {
852        return _STD::forward_as_tuple(_STD::forward<_Types>(get<_I0>(__t))...,
853                                      get<_J0>(_STD::forward<_Tuple0>(__t0))...);
854    }
855
856    template <class _Tuple0, class _Tuple1, class ..._Tuples>
857    _LIBCPP_INLINE_VISIBILITY
858    typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&, _Tuple1&&, _Tuples&&...>::type
859    operator()(tuple<_Types...> __t, _Tuple0&& __t0, _Tuple1&& __t1, _Tuples&& ...__tpls)
860    {
861        typedef typename remove_reference<_Tuple0>::type _T0;
862        typedef typename remove_reference<_Tuple1>::type _T1;
863        return __tuple_cat<
864           tuple<_Types..., typename __apply_cv<_Tuple0, typename tuple_element<_J0, _T0>::type>::type&&...>,
865           typename __make_tuple_indices<sizeof ...(_Types) + tuple_size<_T0>::value>::type,
866           typename __make_tuple_indices<tuple_size<_T1>::value>::type>()
867                           (_STD::forward_as_tuple(
868                              _STD::forward<_Types>(get<_I0>(__t))...,
869                              get<_J0>(_STD::forward<_Tuple0>(__t0))...
870                            ),
871                            _STD::forward<_Tuple1>(__t1),
872                            _STD::forward<_Tuples>(__tpls)...);
873    }
874};
875
876template <class _Tuple0, class... _Tuples>
877inline _LIBCPP_INLINE_VISIBILITY
878typename __tuple_cat_return<_Tuple0, _Tuples...>::type
879tuple_cat(_Tuple0&& __t0, _Tuples&&... __tpls)
880{
881    typedef typename remove_reference<_Tuple0>::type _T0;
882    return __tuple_cat<tuple<>, __tuple_indices<>,
883                  typename __make_tuple_indices<tuple_size<_T0>::value>::type>()
884                  (tuple<>(), _STD::forward<_Tuple0>(__t0),
885                                            _STD::forward<_Tuples>(__tpls)...);
886}
887
888template <class ..._Tp, class _Alloc>
889struct _LIBCPP_VISIBLE uses_allocator<tuple<_Tp...>, _Alloc>
890    : true_type {};
891
892template <class _T1, class _T2>
893template <class... _Args1, class... _Args2, size_t ..._I1, size_t ..._I2>
894inline _LIBCPP_INLINE_VISIBILITY
895pair<_T1, _T2>::pair(piecewise_construct_t,
896                     tuple<_Args1...>& __first_args, tuple<_Args2...>& __second_args,
897                     __tuple_indices<_I1...>, __tuple_indices<_I2...>)
898    :  first(_STD::forward<_Args1>(get<_I1>( __first_args))...),
899      second(_STD::forward<_Args2>(get<_I2>(__second_args))...)
900{
901}
902
903#endif  // _LIBCPP_HAS_NO_VARIADICS
904
905_LIBCPP_END_NAMESPACE_STD
906
907#endif  // _LIBCPP_TUPLE
908