1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP_TUPLE
11#define _LIBCPP_TUPLE
12
13// clang-format off
14
15/*
16    tuple synopsis
17
18namespace std
19{
20
21template <class... T>
22class tuple {
23public:
24    explicit(see-below) constexpr tuple();
25    explicit(see-below) tuple(const T&...);  // constexpr in C++14
26    template <class... U>
27        explicit(see-below) tuple(U&&...);  // constexpr in C++14
28    tuple(const tuple&) = default;
29    tuple(tuple&&) = default;
30
31    template<class... UTypes>
32        constexpr explicit(see-below) tuple(tuple<UTypes...>&);  // C++23
33    template <class... U>
34        explicit(see-below) tuple(const tuple<U...>&);  // constexpr in C++14
35    template <class... U>
36        explicit(see-below) tuple(tuple<U...>&&);  // constexpr in C++14
37    template<class... UTypes>
38        constexpr explicit(see-below) tuple(const tuple<UTypes...>&&); // C++23
39
40    template<class U1, class U2>
41        constexpr explicit(see-below) tuple(pair<U1, U2>&);  // iff sizeof...(Types) == 2 // C++23
42    template <class U1, class U2>
43        explicit(see-below) tuple(const pair<U1, U2>&); // iff sizeof...(T) == 2 // constexpr in C++14
44    template <class U1, class U2>
45        explicit(see-below) tuple(pair<U1, U2>&&); // iff sizeof...(T) == 2  // constexpr in C++14
46    template<class U1, class U2>
47        constexpr explicit(see-below) tuple(const pair<U1, U2>&&);  // iff sizeof...(Types) == 2 // C++23
48
49    // allocator-extended constructors
50    template <class Alloc>
51        tuple(allocator_arg_t, const Alloc& a);
52    template <class Alloc>
53        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, const T&...);          // constexpr in C++20
54    template <class Alloc, class... U>
55        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, U&&...);               // constexpr in C++20
56    template <class Alloc>
57        tuple(allocator_arg_t, const Alloc& a, const tuple&);                             // constexpr in C++20
58    template <class Alloc>
59        tuple(allocator_arg_t, const Alloc& a, tuple&&);                                  // constexpr in C++20
60    template<class Alloc, class... UTypes>
61        constexpr explicit(see-below)
62          tuple(allocator_arg_t, const Alloc& a, tuple<UTypes...>&);                      // C++23
63    template <class Alloc, class... U>
64        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, const tuple<U...>&);   // constexpr in C++20
65    template <class Alloc, class... U>
66        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, tuple<U...>&&);        // constexpr in C++20
67    template<class Alloc, class... UTypes>
68        constexpr explicit(see-below)
69          tuple(allocator_arg_t, const Alloc& a, const tuple<UTypes...>&&);               // C++23
70    template<class Alloc, class U1, class U2>
71        constexpr explicit(see-below)
72          tuple(allocator_arg_t, const Alloc& a, pair<U1, U2>&);                          // C++23
73    template <class Alloc, class U1, class U2>
74        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, const pair<U1, U2>&);  // constexpr in C++20
75    template <class Alloc, class U1, class U2>
76        explicit(see-below) tuple(allocator_arg_t, const Alloc& a, pair<U1, U2>&&);       // constexpr in C++20
77    template<class Alloc, class U1, class U2>
78        constexpr explicit(see-below)
79          tuple(allocator_arg_t, const Alloc& a, const pair<U1, U2>&&);                   // C++23
80
81    tuple& operator=(const tuple&);                                                       // constexpr in C++20
82    constexpr const tuple& operator=(const tuple&) const;                                 // C++23
83    tuple& operator=(tuple&&) noexcept(is_nothrow_move_assignable_v<T> && ...);           // constexpr in C++20
84    constexpr const tuple& operator=(tuple&&) const;                                      // C++23
85    template <class... U>
86        tuple& operator=(const tuple<U...>&);                                             // constexpr in C++20
87    template<class... UTypes>
88        constexpr const tuple& operator=(const tuple<UTypes...>&) const;                  // C++23
89    template <class... U>
90        tuple& operator=(tuple<U...>&&);                                                  // constexpr in C++20
91    template<class... UTypes>
92        constexpr const tuple& operator=(tuple<UTypes...>&&) const;                       // C++23
93    template <class U1, class U2>
94        tuple& operator=(const pair<U1, U2>&); // iff sizeof...(T) == 2                   // constexpr in C++20
95    template<class U1, class U2>
96        constexpr const tuple& operator=(const pair<U1, U2>&) const;   // iff sizeof...(Types) == 2 // C++23
97    template <class U1, class U2>
98        tuple& operator=(pair<U1, U2>&&); // iff sizeof...(T) == 2                        // constexpr in C++20
99    template<class U1, class U2>
100        constexpr const tuple& operator=(pair<U1, U2>&&) const;  // iff sizeof...(Types) == 2 // C++23
101
102    template<class U, size_t N>
103        tuple& operator=(array<U, N> const&) // iff sizeof...(T) == N, EXTENSION
104    template<class U, size_t N>
105        tuple& operator=(array<U, N>&&) // iff sizeof...(T) == N, EXTENSION
106
107    void swap(tuple&) noexcept(AND(swap(declval<T&>(), declval<T&>())...));               // constexpr in C++20
108    constexpr void swap(const tuple&) const noexcept(see-below);                          // C++23
109};
110
111
112template<class... TTypes, class... UTypes, template<class> class TQual, template<class> class UQual> // since C++23
113  requires requires { typename tuple<common_reference_t<TQual<TTypes>, UQual<UTypes>>...>; }
114struct basic_common_reference<tuple<TTypes...>, tuple<UTypes...>, TQual, UQual> {
115  using type = tuple<common_reference_t<TQual<TTypes>, UQual<UTypes>>...>;
116};
117
118template<class... TTypes, class... UTypes>                                // since C++23
119  requires requires { typename tuple<common_type_t<TTypes, UTypes>...>; }
120struct common_type<tuple<TTypes...>, tuple<UTypes...>> {
121  using type = tuple<common_type_t<TTypes, UTypes>...>;
122};
123
124template <class ...T>
125tuple(T...) -> tuple<T...>;                                         // since C++17
126template <class T1, class T2>
127tuple(pair<T1, T2>) -> tuple<T1, T2>;                               // since C++17
128template <class Alloc, class ...T>
129tuple(allocator_arg_t, Alloc, T...) -> tuple<T...>;                 // since C++17
130template <class Alloc, class T1, class T2>
131tuple(allocator_arg_t, Alloc, pair<T1, T2>) -> tuple<T1, T2>;       // since C++17
132template <class Alloc, class ...T>
133tuple(allocator_arg_t, Alloc, tuple<T...>) -> tuple<T...>;          // since C++17
134
135inline constexpr unspecified ignore;
136
137template <class... T> tuple<V...>  make_tuple(T&&...); // constexpr in C++14
138template <class... T> tuple<ATypes...> forward_as_tuple(T&&...) noexcept; // constexpr in C++14
139template <class... T> tuple<T&...> tie(T&...) noexcept; // constexpr in C++14
140template <class... Tuples> tuple<CTypes...> tuple_cat(Tuples&&... tpls); // constexpr in C++14
141
142// [tuple.apply], calling a function with a tuple of arguments:
143template <class F, class Tuple>
144  constexpr decltype(auto) apply(F&& f, Tuple&& t) noexcept(see below);  // C++17 noexcept since C++23
145template <class T, class Tuple>
146  constexpr T make_from_tuple(Tuple&& t); // C++17
147
148// 20.4.1.4, tuple helper classes:
149template <class T> struct tuple_size; // undefined
150template <class... T> struct tuple_size<tuple<T...>>;
151template <class T>
152 inline constexpr size_t tuple_size_v = tuple_size<T>::value; // C++17
153template <size_t I, class T> struct tuple_element; // undefined
154template <size_t I, class... T> struct tuple_element<I, tuple<T...>>;
155template <size_t I, class T>
156  using tuple_element_t = typename tuple_element <I, T>::type; // C++14
157
158// 20.4.1.5, element access:
159template <size_t I, class... T>
160    typename tuple_element<I, tuple<T...>>::type&
161    get(tuple<T...>&) noexcept; // constexpr in C++14
162template <size_t I, class... T>
163    const typename tuple_element<I, tuple<T...>>::type&
164    get(const tuple<T...>&) noexcept; // constexpr in C++14
165template <size_t I, class... T>
166    typename tuple_element<I, tuple<T...>>::type&&
167    get(tuple<T...>&&) noexcept; // constexpr in C++14
168template <size_t I, class... T>
169    const typename tuple_element<I, tuple<T...>>::type&&
170    get(const tuple<T...>&&) noexcept; // constexpr in C++14
171
172template <class T1, class... T>
173    constexpr T1& get(tuple<T...>&) noexcept;  // C++14
174template <class T1, class... T>
175    constexpr const T1& get(const tuple<T...>&) noexcept;   // C++14
176template <class T1, class... T>
177    constexpr T1&& get(tuple<T...>&&) noexcept;   // C++14
178template <class T1, class... T>
179    constexpr const T1&& get(const tuple<T...>&&) noexcept;   // C++14
180
181// 20.4.1.6, relational operators:
182template<class... T, class... U> bool operator==(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14
183template<class... T, class... U> bool operator<(const tuple<T...>&, const tuple<U...>&);  // constexpr in C++14, removed in C++20
184template<class... T, class... U> bool operator!=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14, removed in C++20
185template<class... T, class... U> bool operator>(const tuple<T...>&, const tuple<U...>&);  // constexpr in C++14, removed in C++20
186template<class... T, class... U> bool operator<=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14, removed in C++20
187template<class... T, class... U> bool operator>=(const tuple<T...>&, const tuple<U...>&); // constexpr in C++14, removed in C++20
188template<class... T, class... U>
189  constexpr common_comparison_category_t<synth-three-way-result<T, U>...>
190    operator<=>(const tuple<T...>&, const tuple<U...>&);                                  // since C++20
191
192template <class... Types, class Alloc>
193  struct uses_allocator<tuple<Types...>, Alloc>;
194
195template <class... Types>
196  void
197  swap(tuple<Types...>& x, tuple<Types...>& y) noexcept(noexcept(x.swap(y)));
198
199template <class... Types>
200  constexpr void swap(const tuple<Types...>& x, const tuple<Types...>& y) noexcept(see-below);   // C++23
201
202}  // std
203
204*/
205
206// clang-format on
207
208#include <__compare/common_comparison_category.h>
209#include <__compare/synth_three_way.h>
210#include <__config>
211#include <__functional/invoke.h>
212#include <__fwd/array.h>
213#include <__fwd/tuple.h>
214#include <__memory/allocator_arg_t.h>
215#include <__memory/uses_allocator.h>
216#include <__tuple/find_index.h>
217#include <__tuple/make_tuple_types.h>
218#include <__tuple/sfinae_helpers.h>
219#include <__tuple/tuple_element.h>
220#include <__tuple/tuple_indices.h>
221#include <__tuple/tuple_like_ext.h>
222#include <__tuple/tuple_size.h>
223#include <__tuple/tuple_types.h>
224#include <__type_traits/apply_cv.h>
225#include <__type_traits/common_reference.h>
226#include <__type_traits/common_type.h>
227#include <__type_traits/conditional.h>
228#include <__type_traits/conjunction.h>
229#include <__type_traits/copy_cvref.h>
230#include <__type_traits/disjunction.h>
231#include <__type_traits/is_arithmetic.h>
232#include <__type_traits/is_assignable.h>
233#include <__type_traits/is_constructible.h>
234#include <__type_traits/is_convertible.h>
235#include <__type_traits/is_copy_assignable.h>
236#include <__type_traits/is_copy_constructible.h>
237#include <__type_traits/is_default_constructible.h>
238#include <__type_traits/is_empty.h>
239#include <__type_traits/is_final.h>
240#include <__type_traits/is_implicitly_default_constructible.h>
241#include <__type_traits/is_move_assignable.h>
242#include <__type_traits/is_move_constructible.h>
243#include <__type_traits/is_nothrow_assignable.h>
244#include <__type_traits/is_nothrow_constructible.h>
245#include <__type_traits/is_nothrow_copy_assignable.h>
246#include <__type_traits/is_nothrow_copy_constructible.h>
247#include <__type_traits/is_nothrow_default_constructible.h>
248#include <__type_traits/is_nothrow_move_assignable.h>
249#include <__type_traits/is_reference.h>
250#include <__type_traits/is_same.h>
251#include <__type_traits/is_swappable.h>
252#include <__type_traits/lazy.h>
253#include <__type_traits/maybe_const.h>
254#include <__type_traits/nat.h>
255#include <__type_traits/negation.h>
256#include <__type_traits/remove_cvref.h>
257#include <__type_traits/remove_reference.h>
258#include <__type_traits/unwrap_ref.h>
259#include <__utility/forward.h>
260#include <__utility/integer_sequence.h>
261#include <__utility/move.h>
262#include <__utility/pair.h>
263#include <__utility/piecewise_construct.h>
264#include <__utility/swap.h>
265#include <cstddef>
266#include <version>
267
268// standard-mandated includes
269
270// [tuple.syn]
271#include <compare>
272
273#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
274#  pragma GCC system_header
275#endif
276
277_LIBCPP_PUSH_MACROS
278#include <__undef_macros>
279
280_LIBCPP_BEGIN_NAMESPACE_STD
281
282#ifndef _LIBCPP_CXX03_LANG
283
284// __tuple_leaf
285
286template <size_t _Ip, class _Hp, bool = is_empty<_Hp>::value && !__libcpp_is_final<_Hp>::value >
287class __tuple_leaf;
288
289template <size_t _Ip, class _Hp, bool _Ep>
290inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
291swap(__tuple_leaf<_Ip, _Hp, _Ep>& __x, __tuple_leaf<_Ip, _Hp, _Ep>& __y)
292    _NOEXCEPT_(__is_nothrow_swappable<_Hp>::value) {
293  swap(__x.get(), __y.get());
294}
295
296template <size_t _Ip, class _Hp, bool _Ep>
297_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
298swap(const __tuple_leaf<_Ip, _Hp, _Ep>& __x, const __tuple_leaf<_Ip, _Hp, _Ep>& __y)
299    _NOEXCEPT_(__is_nothrow_swappable<const _Hp>::value) {
300  swap(__x.get(), __y.get());
301}
302
303template <size_t _Ip, class _Hp, bool>
304class __tuple_leaf {
305  _Hp __value_;
306
307  template <class _Tp>
308  static _LIBCPP_HIDE_FROM_ABI constexpr bool __can_bind_reference() {
309#  if __has_keyword(__reference_binds_to_temporary)
310    return !__reference_binds_to_temporary(_Hp, _Tp);
311#  else
312    return true;
313#  endif
314  }
315
316  _LIBCPP_CONSTEXPR_SINCE_CXX14 __tuple_leaf& operator=(const __tuple_leaf&);
317
318public:
319  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_leaf() _NOEXCEPT_(is_nothrow_default_constructible<_Hp>::value) : __value_() {
320    static_assert(!is_reference<_Hp>::value, "Attempted to default construct a reference element in a tuple");
321  }
322
323  template <class _Alloc>
324  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_leaf(integral_constant<int, 0>, const _Alloc&) : __value_() {
325    static_assert(!is_reference<_Hp>::value, "Attempted to default construct a reference element in a tuple");
326  }
327
328  template <class _Alloc>
329  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a)
330      : __value_(allocator_arg_t(), __a) {
331    static_assert(!is_reference<_Hp>::value, "Attempted to default construct a reference element in a tuple");
332  }
333
334  template <class _Alloc>
335  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a) : __value_(__a) {
336    static_assert(!is_reference<_Hp>::value, "Attempted to default construct a reference element in a tuple");
337  }
338
339  template <class _Tp,
340            __enable_if_t<_And<_IsNotSame<__remove_cvref_t<_Tp>, __tuple_leaf>, is_constructible<_Hp, _Tp> >::value,
341                           int> = 0>
342  _LIBCPP_HIDE_FROM_ABI
343  _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __tuple_leaf(_Tp&& __t) _NOEXCEPT_(is_nothrow_constructible<_Hp, _Tp>::value)
344      : __value_(std::forward<_Tp>(__t)) {
345    static_assert(__can_bind_reference<_Tp&&>(),
346                  "Attempted construction of reference element binds to a temporary whose lifetime has ended");
347  }
348
349  template <class _Tp, class _Alloc>
350  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __tuple_leaf(
351      integral_constant<int, 0>, const _Alloc&, _Tp&& __t)
352      : __value_(std::forward<_Tp>(__t)) {
353    static_assert(__can_bind_reference<_Tp&&>(),
354                  "Attempted construction of reference element binds to a temporary whose lifetime has ended");
355  }
356
357  template <class _Tp, class _Alloc>
358  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __tuple_leaf(
359      integral_constant<int, 1>, const _Alloc& __a, _Tp&& __t)
360      : __value_(allocator_arg_t(), __a, std::forward<_Tp>(__t)) {
361    static_assert(!is_reference<_Hp>::value, "Attempted to uses-allocator construct a reference element in a tuple");
362  }
363
364  template <class _Tp, class _Alloc>
365  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __tuple_leaf(
366      integral_constant<int, 2>, const _Alloc& __a, _Tp&& __t)
367      : __value_(std::forward<_Tp>(__t), __a) {
368    static_assert(!is_reference<_Hp>::value, "Attempted to uses-allocator construct a reference element in a tuple");
369  }
370
371  _LIBCPP_HIDE_FROM_ABI __tuple_leaf(const __tuple_leaf& __t) = default;
372  _LIBCPP_HIDE_FROM_ABI __tuple_leaf(__tuple_leaf&& __t)      = default;
373
374  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 int swap(__tuple_leaf& __t)
375      _NOEXCEPT_(__is_nothrow_swappable<__tuple_leaf>::value) {
376    std::swap(*this, __t);
377    return 0;
378  }
379
380  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 int swap(const __tuple_leaf& __t) const
381      _NOEXCEPT_(__is_nothrow_swappable<const __tuple_leaf>::value) {
382    std::swap(*this, __t);
383    return 0;
384  }
385
386  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Hp& get() _NOEXCEPT { return __value_; }
387  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const _Hp& get() const _NOEXCEPT { return __value_; }
388};
389
390template <size_t _Ip, class _Hp>
391class __tuple_leaf<_Ip, _Hp, true> : private _Hp {
392  _LIBCPP_CONSTEXPR_SINCE_CXX14 __tuple_leaf& operator=(const __tuple_leaf&);
393
394public:
395  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_leaf() _NOEXCEPT_(is_nothrow_default_constructible<_Hp>::value) {}
396
397  template <class _Alloc>
398  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_leaf(integral_constant<int, 0>, const _Alloc&) {}
399
400  template <class _Alloc>
401  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a)
402      : _Hp(allocator_arg_t(), __a) {}
403
404  template <class _Alloc>
405  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a) : _Hp(__a) {}
406
407  template <class _Tp,
408            __enable_if_t< _And< _IsNotSame<__remove_cvref_t<_Tp>, __tuple_leaf>, is_constructible<_Hp, _Tp> >::value,
409                           int> = 0>
410  _LIBCPP_HIDE_FROM_ABI
411  _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __tuple_leaf(_Tp&& __t) _NOEXCEPT_(is_nothrow_constructible<_Hp, _Tp>::value)
412      : _Hp(std::forward<_Tp>(__t)) {}
413
414  template <class _Tp, class _Alloc>
415  _LIBCPP_HIDE_FROM_ABI constexpr explicit __tuple_leaf(integral_constant<int, 0>, const _Alloc&, _Tp&& __t)
416      : _Hp(std::forward<_Tp>(__t)) {}
417
418  template <class _Tp, class _Alloc>
419  _LIBCPP_HIDE_FROM_ABI constexpr explicit __tuple_leaf(integral_constant<int, 1>, const _Alloc& __a, _Tp&& __t)
420      : _Hp(allocator_arg_t(), __a, std::forward<_Tp>(__t)) {}
421
422  template <class _Tp, class _Alloc>
423  _LIBCPP_HIDE_FROM_ABI constexpr explicit __tuple_leaf(integral_constant<int, 2>, const _Alloc& __a, _Tp&& __t)
424      : _Hp(std::forward<_Tp>(__t), __a) {}
425
426  __tuple_leaf(__tuple_leaf const&) = default;
427  __tuple_leaf(__tuple_leaf&&)      = default;
428
429  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 int swap(__tuple_leaf& __t)
430      _NOEXCEPT_(__is_nothrow_swappable<__tuple_leaf>::value) {
431    std::swap(*this, __t);
432    return 0;
433  }
434
435  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 int swap(const __tuple_leaf& __rhs) const
436      _NOEXCEPT_(__is_nothrow_swappable<const __tuple_leaf>::value) {
437    std::swap(*this, __rhs);
438    return 0;
439  }
440
441  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Hp& get() _NOEXCEPT { return static_cast<_Hp&>(*this); }
442  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const _Hp& get() const _NOEXCEPT {
443    return static_cast<const _Hp&>(*this);
444  }
445};
446
447template <class... _Tp>
448_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void __swallow(_Tp&&...) _NOEXCEPT {}
449
450template <class _Tp>
451struct __all_default_constructible;
452
453template <class... _Tp>
454struct __all_default_constructible<__tuple_types<_Tp...>> : __all<is_default_constructible<_Tp>::value...> {};
455
456// __tuple_impl
457
458template <class _Indx, class... _Tp>
459struct __tuple_impl;
460
461template <size_t... _Indx, class... _Tp>
462struct _LIBCPP_DECLSPEC_EMPTY_BASES __tuple_impl<__tuple_indices<_Indx...>, _Tp...>
463    : public __tuple_leaf<_Indx, _Tp>... {
464  _LIBCPP_HIDE_FROM_ABI constexpr __tuple_impl()
465      _NOEXCEPT_(__all<is_nothrow_default_constructible<_Tp>::value...>::value) {}
466
467  template <size_t... _Uf, class... _Tf, size_t... _Ul, class... _Tl, class... _Up>
468  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __tuple_impl(
469      __tuple_indices<_Uf...>, __tuple_types<_Tf...>, __tuple_indices<_Ul...>, __tuple_types<_Tl...>, _Up&&... __u)
470      _NOEXCEPT_(__all<is_nothrow_constructible<_Tf, _Up>::value...>::value&&
471                     __all<is_nothrow_default_constructible<_Tl>::value...>::value)
472      : __tuple_leaf<_Uf, _Tf>(std::forward<_Up>(__u))..., __tuple_leaf<_Ul, _Tl>()... {}
473
474  template <class _Alloc, size_t... _Uf, class... _Tf, size_t... _Ul, class... _Tl, class... _Up>
475  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit __tuple_impl(
476      allocator_arg_t,
477      const _Alloc& __a,
478      __tuple_indices<_Uf...>,
479      __tuple_types<_Tf...>,
480      __tuple_indices<_Ul...>,
481      __tuple_types<_Tl...>,
482      _Up&&... __u)
483      : __tuple_leaf<_Uf, _Tf>(__uses_alloc_ctor<_Tf, _Alloc, _Up>(), __a, std::forward<_Up>(__u))...,
484        __tuple_leaf<_Ul, _Tl>(__uses_alloc_ctor<_Tl, _Alloc>(), __a)... {}
485
486  template <class _Tuple, __enable_if_t<__tuple_constructible<_Tuple, tuple<_Tp...> >::value, int> = 0>
487  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __tuple_impl(_Tuple&& __t) _NOEXCEPT_(
488      (__all<is_nothrow_constructible<
489           _Tp,
490           typename tuple_element<_Indx, typename __make_tuple_types<_Tuple>::type>::type>::value...>::value))
491      : __tuple_leaf<_Indx, _Tp>(
492            std::forward<typename tuple_element<_Indx, typename __make_tuple_types<_Tuple>::type>::type>(
493                std::get<_Indx>(__t)))... {}
494
495  template <class _Alloc, class _Tuple, __enable_if_t<__tuple_constructible<_Tuple, tuple<_Tp...> >::value, int> = 0>
496  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 __tuple_impl(allocator_arg_t, const _Alloc& __a, _Tuple&& __t)
497      : __tuple_leaf<_Indx, _Tp>(
498            __uses_alloc_ctor<_Tp,
499                              _Alloc,
500                              typename tuple_element<_Indx, typename __make_tuple_types<_Tuple>::type>::type>(),
501            __a,
502            std::forward<typename tuple_element<_Indx, typename __make_tuple_types<_Tuple>::type>::type>(
503                std::get<_Indx>(__t)))... {}
504
505  __tuple_impl(const __tuple_impl&) = default;
506  __tuple_impl(__tuple_impl&&)      = default;
507
508  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void swap(__tuple_impl& __t)
509      _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value) {
510    std::__swallow(__tuple_leaf<_Indx, _Tp>::swap(static_cast<__tuple_leaf<_Indx, _Tp>&>(__t))...);
511  }
512
513  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void swap(const __tuple_impl& __t) const
514      _NOEXCEPT_(__all<__is_nothrow_swappable<const _Tp>::value...>::value) {
515    std::__swallow(__tuple_leaf<_Indx, _Tp>::swap(static_cast<const __tuple_leaf<_Indx, _Tp>&>(__t))...);
516  }
517};
518
519template <class _Dest, class _Source, size_t... _Np>
520_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
521__memberwise_copy_assign(_Dest& __dest, _Source const& __source, __tuple_indices<_Np...>) {
522  std::__swallow(((std::get<_Np>(__dest) = std::get<_Np>(__source)), void(), 0)...);
523}
524
525template <class _Dest, class _Source, class... _Up, size_t... _Np>
526_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
527__memberwise_forward_assign(_Dest& __dest, _Source&& __source, __tuple_types<_Up...>, __tuple_indices<_Np...>) {
528  std::__swallow(((std::get<_Np>(__dest) = std::forward<_Up>(std::get<_Np>(__source))), void(), 0)...);
529}
530
531template <class... _Tp>
532class _LIBCPP_TEMPLATE_VIS tuple {
533  typedef __tuple_impl<typename __make_tuple_indices<sizeof...(_Tp)>::type, _Tp...> _BaseT;
534
535  _BaseT __base_;
536
537  template <size_t _Jp, class... _Up>
538  friend _LIBCPP_CONSTEXPR_SINCE_CXX14 typename tuple_element<_Jp, tuple<_Up...> >::type& get(tuple<_Up...>&) _NOEXCEPT;
539  template <size_t _Jp, class... _Up>
540  friend _LIBCPP_CONSTEXPR_SINCE_CXX14 const typename tuple_element<_Jp, tuple<_Up...> >::type&
541  get(const tuple<_Up...>&) _NOEXCEPT;
542  template <size_t _Jp, class... _Up>
543  friend _LIBCPP_CONSTEXPR_SINCE_CXX14 typename tuple_element<_Jp, tuple<_Up...> >::type&&
544  get(tuple<_Up...>&&) _NOEXCEPT;
545  template <size_t _Jp, class... _Up>
546  friend _LIBCPP_CONSTEXPR_SINCE_CXX14 const typename tuple_element<_Jp, tuple<_Up...> >::type&&
547  get(const tuple<_Up...>&&) _NOEXCEPT;
548
549public:
550  // [tuple.cnstr]
551
552  // tuple() constructors (including allocator_arg_t variants)
553  template <template <class...> class _IsImpDefault                = __is_implicitly_default_constructible,
554            template <class...> class _IsDefault                   = is_default_constructible,
555            __enable_if_t< _And< _IsDefault<_Tp>... >::value, int> = 0>
556  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR explicit(_Not<_Lazy<_And, _IsImpDefault<_Tp>...> >::value) tuple()
557      _NOEXCEPT_(_And<is_nothrow_default_constructible<_Tp>...>::value) {}
558
559  template <class _Alloc,
560            template <class...> class _IsImpDefault                = __is_implicitly_default_constructible,
561            template <class...> class _IsDefault                   = is_default_constructible,
562            __enable_if_t< _And< _IsDefault<_Tp>... >::value, int> = 0>
563  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit(_Not<_Lazy<_And, _IsImpDefault<_Tp>...> >::value)
564      tuple(allocator_arg_t, _Alloc const& __a)
565      : __base_(allocator_arg_t(),
566                __a,
567                __tuple_indices<>(),
568                __tuple_types<>(),
569                typename __make_tuple_indices<sizeof...(_Tp), 0>::type(),
570                __tuple_types<_Tp...>()) {}
571
572  // tuple(const T&...) constructors (including allocator_arg_t variants)
573  template <template <class...> class _And = _And,
574            __enable_if_t< _And< _BoolConstant<sizeof...(_Tp) >= 1>, is_copy_constructible<_Tp>... >::value, int> = 0>
575  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit(
576      _Not<_Lazy<_And, is_convertible<const _Tp&, _Tp>...> >::value) tuple(const _Tp&... __t)
577      _NOEXCEPT_(_And<is_nothrow_copy_constructible<_Tp>...>::value)
578      : __base_(typename __make_tuple_indices<sizeof...(_Tp)>::type(),
579                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
580                typename __make_tuple_indices<0>::type(),
581                typename __make_tuple_types<tuple, 0>::type(),
582                __t...) {}
583
584  template <class _Alloc,
585            template <class...> class _And = _And,
586            __enable_if_t< _And< _BoolConstant<sizeof...(_Tp) >= 1>, is_copy_constructible<_Tp>... >::value, int> = 0>
587  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit(
588      _Not<_Lazy<_And, is_convertible<const _Tp&, _Tp>...> >::value)
589      tuple(allocator_arg_t, const _Alloc& __a, const _Tp&... __t)
590      : __base_(allocator_arg_t(),
591                __a,
592                typename __make_tuple_indices<sizeof...(_Tp)>::type(),
593                typename __make_tuple_types<tuple, sizeof...(_Tp)>::type(),
594                typename __make_tuple_indices<0>::type(),
595                typename __make_tuple_types<tuple, 0>::type(),
596                __t...) {}
597
598  // tuple(U&& ...) constructors (including allocator_arg_t variants)
599  template <class... _Up>
600  struct _IsThisTuple : false_type {};
601  template <class _Up>
602  struct _IsThisTuple<_Up> : is_same<__remove_cvref_t<_Up>, tuple> {};
603
604  template <class... _Up>
605  struct _EnableUTypesCtor
606      : _And< _BoolConstant<sizeof...(_Tp) >= 1>,
607              _Not<_IsThisTuple<_Up...> >, // extension to allow mis-behaved user constructors
608              is_constructible<_Tp, _Up>... > {};
609
610  template <class... _Up,
611            __enable_if_t< _And< _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>, _EnableUTypesCtor<_Up...> >::value,
612                           int> = 0>
613  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit(_Not<_Lazy<_And, is_convertible<_Up, _Tp>...> >::value)
614      tuple(_Up&&... __u) _NOEXCEPT_(_And<is_nothrow_constructible<_Tp, _Up>...>::value)
615      : __base_(typename __make_tuple_indices<sizeof...(_Up)>::type(),
616                typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
617                typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
618                typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
619                std::forward<_Up>(__u)...) {}
620
621  template <class _Alloc,
622            class... _Up,
623            __enable_if_t< _And< _BoolConstant<sizeof...(_Up) == sizeof...(_Tp)>, _EnableUTypesCtor<_Up...> >::value,
624                           int> = 0>
625  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit(_Not<_Lazy<_And, is_convertible<_Up, _Tp>...> >::value)
626      tuple(allocator_arg_t, const _Alloc& __a, _Up&&... __u)
627      : __base_(allocator_arg_t(),
628                __a,
629                typename __make_tuple_indices<sizeof...(_Up)>::type(),
630                typename __make_tuple_types<tuple, sizeof...(_Up)>::type(),
631                typename __make_tuple_indices<sizeof...(_Tp), sizeof...(_Up)>::type(),
632                typename __make_tuple_types<tuple, sizeof...(_Tp), sizeof...(_Up)>::type(),
633                std::forward<_Up>(__u)...) {}
634
635  // Copy and move constructors (including the allocator_arg_t variants)
636  tuple(const tuple&) = default;
637  tuple(tuple&&)      = default;
638
639  template <class _Alloc,
640            template <class...> class _And                                  = _And,
641            __enable_if_t< _And<is_copy_constructible<_Tp>...>::value, int> = 0>
642  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple(allocator_arg_t, const _Alloc& __alloc, const tuple& __t)
643      : __base_(allocator_arg_t(), __alloc, __t) {}
644
645  template <class _Alloc,
646            template <class...> class _And                                  = _And,
647            __enable_if_t< _And<is_move_constructible<_Tp>...>::value, int> = 0>
648  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple(allocator_arg_t, const _Alloc& __alloc, tuple&& __t)
649      : __base_(allocator_arg_t(), __alloc, std::move(__t)) {}
650
651  // tuple(const tuple<U...>&) constructors (including allocator_arg_t variants)
652
653  template <class _OtherTuple, class _DecayedOtherTuple = __remove_cvref_t<_OtherTuple>, class = void>
654  struct _EnableCtorFromUTypesTuple : false_type {};
655
656  template <class _OtherTuple, class... _Up>
657  struct _EnableCtorFromUTypesTuple<
658      _OtherTuple,
659      tuple<_Up...>,
660      // the length of the packs needs to checked first otherwise the 2 packs cannot be expanded simultaneously below
661      __enable_if_t<sizeof...(_Up) == sizeof...(_Tp)>>
662      : _And<
663            // the two conditions below are not in spec. The purpose is to disable the UTypes Ctor when copy/move Ctor
664            // can work. Otherwise, is_constructible can trigger hard error in those cases
665            // https://godbolt.org/z/M94cGdKcE
666            _Not<is_same<_OtherTuple, const tuple&> >,
667            _Not<is_same<_OtherTuple, tuple&&> >,
668            is_constructible<_Tp, __copy_cvref_t<_OtherTuple, _Up> >...,
669            _Lazy<_Or,
670                  _BoolConstant<sizeof...(_Tp) != 1>,
671                  // _Tp and _Up are 1-element packs - the pack expansions look
672                  // weird to avoid tripping up the type traits in degenerate cases
673                  _Lazy<_And,
674                        _Not<is_same<_Tp, _Up> >...,
675                        _Not<is_convertible<_OtherTuple, _Tp> >...,
676                        _Not<is_constructible<_Tp, _OtherTuple> >... > > > {};
677
678  template <class... _Up, __enable_if_t< _And< _EnableCtorFromUTypesTuple<const tuple<_Up...>&> >::value, int> = 0>
679  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit(
680      _Not<_Lazy<_And, is_convertible<const _Up&, _Tp>...> >::value) tuple(const tuple<_Up...>& __t)
681      _NOEXCEPT_(_And<is_nothrow_constructible<_Tp, const _Up&>...>::value)
682      : __base_(__t) {}
683
684  template <class... _Up,
685            class _Alloc,
686            __enable_if_t< _And< _EnableCtorFromUTypesTuple<const tuple<_Up...>&> >::value, int> = 0>
687  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit(
688      _Not<_Lazy<_And, is_convertible<const _Up&, _Tp>...> >::value)
689      tuple(allocator_arg_t, const _Alloc& __a, const tuple<_Up...>& __t)
690      : __base_(allocator_arg_t(), __a, __t) {}
691
692#  if _LIBCPP_STD_VER >= 23
693  // tuple(tuple<U...>&) constructors (including allocator_arg_t variants)
694
695  template <class... _Up, enable_if_t< _EnableCtorFromUTypesTuple<tuple<_Up...>&>::value>* = nullptr>
696  _LIBCPP_HIDE_FROM_ABI constexpr explicit(!_Lazy<_And, is_convertible<_Up&, _Tp>...>::value) tuple(tuple<_Up...>& __t)
697      : __base_(__t) {}
698
699  template <class _Alloc, class... _Up, enable_if_t< _EnableCtorFromUTypesTuple<tuple<_Up...>&>::value>* = nullptr>
700  _LIBCPP_HIDE_FROM_ABI constexpr explicit(!_Lazy<_And, is_convertible<_Up&, _Tp>...>::value)
701      tuple(allocator_arg_t, const _Alloc& __alloc, tuple<_Up...>& __t)
702      : __base_(allocator_arg_t(), __alloc, __t) {}
703#  endif // _LIBCPP_STD_VER >= 23
704
705  // tuple(tuple<U...>&&) constructors (including allocator_arg_t variants)
706  template <class... _Up, __enable_if_t< _And< _EnableCtorFromUTypesTuple<tuple<_Up...>&&> >::value, int> = 0>
707  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit(_Not<_Lazy<_And, is_convertible<_Up, _Tp>...> >::value)
708      tuple(tuple<_Up...>&& __t) _NOEXCEPT_(_And<is_nothrow_constructible<_Tp, _Up>...>::value)
709      : __base_(std::move(__t)) {}
710
711  template <class _Alloc,
712            class... _Up,
713            __enable_if_t< _And< _EnableCtorFromUTypesTuple<tuple<_Up...>&&> >::value, int> = 0>
714  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit(_Not<_Lazy<_And, is_convertible<_Up, _Tp>...> >::value)
715      tuple(allocator_arg_t, const _Alloc& __a, tuple<_Up...>&& __t)
716      : __base_(allocator_arg_t(), __a, std::move(__t)) {}
717
718#  if _LIBCPP_STD_VER >= 23
719  // tuple(const tuple<U...>&&) constructors (including allocator_arg_t variants)
720
721  template <class... _Up, enable_if_t< _EnableCtorFromUTypesTuple<const tuple<_Up...>&&>::value>* = nullptr>
722  _LIBCPP_HIDE_FROM_ABI constexpr explicit(!_Lazy<_And, is_convertible<const _Up&&, _Tp>...>::value)
723      tuple(const tuple<_Up...>&& __t)
724      : __base_(std::move(__t)) {}
725
726  template <class _Alloc,
727            class... _Up,
728            enable_if_t< _EnableCtorFromUTypesTuple<const tuple<_Up...>&&>::value>* = nullptr>
729  _LIBCPP_HIDE_FROM_ABI constexpr explicit(!_Lazy<_And, is_convertible<const _Up&&, _Tp>...>::value)
730      tuple(allocator_arg_t, const _Alloc& __alloc, const tuple<_Up...>&& __t)
731      : __base_(allocator_arg_t(), __alloc, std::move(__t)) {}
732#  endif // _LIBCPP_STD_VER >= 23
733
734  // tuple(const pair<U1, U2>&) constructors (including allocator_arg_t variants)
735
736  template <template <class...> class _Pred,
737            class _Pair,
738            class _DecayedPair = __remove_cvref_t<_Pair>,
739            class _Tuple       = tuple>
740  struct _CtorPredicateFromPair : false_type {};
741
742  template <template <class...> class _Pred, class _Pair, class _Up1, class _Up2, class _Tp1, class _Tp2>
743  struct _CtorPredicateFromPair<_Pred, _Pair, pair<_Up1, _Up2>, tuple<_Tp1, _Tp2> >
744      : _And< _Pred<_Tp1, __copy_cvref_t<_Pair, _Up1> >, _Pred<_Tp2, __copy_cvref_t<_Pair, _Up2> > > {};
745
746  template <class _Pair>
747  struct _EnableCtorFromPair : _CtorPredicateFromPair<is_constructible, _Pair> {};
748
749  template <class _Pair>
750  struct _NothrowConstructibleFromPair : _CtorPredicateFromPair<is_nothrow_constructible, _Pair> {};
751
752  template <class _Pair, class _DecayedPair = __remove_cvref_t<_Pair>, class _Tuple = tuple>
753  struct _BothImplicitlyConvertible : false_type {};
754
755  template <class _Pair, class _Up1, class _Up2, class _Tp1, class _Tp2>
756  struct _BothImplicitlyConvertible<_Pair, pair<_Up1, _Up2>, tuple<_Tp1, _Tp2> >
757      : _And< is_convertible<__copy_cvref_t<_Pair, _Up1>, _Tp1>, is_convertible<__copy_cvref_t<_Pair, _Up2>, _Tp2> > {};
758
759  template <class _Up1,
760            class _Up2,
761            template <class...> class _And                                                   = _And,
762            __enable_if_t< _And< _EnableCtorFromPair<const pair<_Up1, _Up2>&> >::value, int> = 0>
763  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit(
764      _Not<_BothImplicitlyConvertible<const pair<_Up1, _Up2>&> >::value) tuple(const pair<_Up1, _Up2>& __p)
765      _NOEXCEPT_(_NothrowConstructibleFromPair<const pair<_Up1, _Up2>&>::value)
766      : __base_(__p) {}
767
768  template <class _Alloc,
769            class _Up1,
770            class _Up2,
771            template <class...> class _And                                                   = _And,
772            __enable_if_t< _And< _EnableCtorFromPair<const pair<_Up1, _Up2>&> >::value, int> = 0>
773  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit(
774      _Not<_BothImplicitlyConvertible<const pair<_Up1, _Up2>&> >::value)
775      tuple(allocator_arg_t, const _Alloc& __a, const pair<_Up1, _Up2>& __p)
776      : __base_(allocator_arg_t(), __a, __p) {}
777
778#  if _LIBCPP_STD_VER >= 23
779  // tuple(pair<U1, U2>&) constructors (including allocator_arg_t variants)
780
781  template <class _U1, class _U2, enable_if_t< _EnableCtorFromPair<pair<_U1, _U2>&>::value>* = nullptr>
782  _LIBCPP_HIDE_FROM_ABI constexpr explicit(!_BothImplicitlyConvertible<pair<_U1, _U2>&>::value)
783      tuple(pair<_U1, _U2>& __p)
784      : __base_(__p) {}
785
786  template <class _Alloc,
787            class _U1,
788            class _U2,
789            enable_if_t< _EnableCtorFromPair<std::pair<_U1, _U2>&>::value>* = nullptr>
790  _LIBCPP_HIDE_FROM_ABI constexpr explicit(!_BothImplicitlyConvertible<pair<_U1, _U2>&>::value)
791      tuple(allocator_arg_t, const _Alloc& __alloc, pair<_U1, _U2>& __p)
792      : __base_(allocator_arg_t(), __alloc, __p) {}
793#  endif
794
795  // tuple(pair<U1, U2>&&) constructors (including allocator_arg_t variants)
796
797  template <class _Up1,
798            class _Up2,
799            template <class...> class _And                                              = _And,
800            __enable_if_t< _And< _EnableCtorFromPair<pair<_Up1, _Up2>&&> >::value, int> = 0>
801  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 explicit(
802      _Not<_BothImplicitlyConvertible<pair<_Up1, _Up2>&&> >::value) tuple(pair<_Up1, _Up2>&& __p)
803      _NOEXCEPT_(_NothrowConstructibleFromPair<pair<_Up1, _Up2>&&>::value)
804      : __base_(std::move(__p)) {}
805
806  template <class _Alloc,
807            class _Up1,
808            class _Up2,
809            template <class...> class _And                                              = _And,
810            __enable_if_t< _And< _EnableCtorFromPair<pair<_Up1, _Up2>&&> >::value, int> = 0>
811  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit(
812      _Not<_BothImplicitlyConvertible<pair<_Up1, _Up2>&&> >::value)
813      tuple(allocator_arg_t, const _Alloc& __a, pair<_Up1, _Up2>&& __p)
814      : __base_(allocator_arg_t(), __a, std::move(__p)) {}
815
816#  if _LIBCPP_STD_VER >= 23
817  // tuple(const pair<U1, U2>&&) constructors (including allocator_arg_t variants)
818
819  template <class _U1, class _U2, enable_if_t< _EnableCtorFromPair<const pair<_U1, _U2>&&>::value>* = nullptr>
820  _LIBCPP_HIDE_FROM_ABI constexpr explicit(!_BothImplicitlyConvertible<const pair<_U1, _U2>&&>::value)
821      tuple(const pair<_U1, _U2>&& __p)
822      : __base_(std::move(__p)) {}
823
824  template <class _Alloc,
825            class _U1,
826            class _U2,
827            enable_if_t< _EnableCtorFromPair<const pair<_U1, _U2>&&>::value>* = nullptr>
828  _LIBCPP_HIDE_FROM_ABI constexpr explicit(!_BothImplicitlyConvertible<const pair<_U1, _U2>&&>::value)
829      tuple(allocator_arg_t, const _Alloc& __alloc, const pair<_U1, _U2>&& __p)
830      : __base_(allocator_arg_t(), __alloc, std::move(__p)) {}
831#  endif // _LIBCPP_STD_VER >= 23
832
833  // [tuple.assign]
834  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple&
835  operator=(_If<_And<is_copy_assignable<_Tp>...>::value, tuple, __nat> const& __tuple)
836      _NOEXCEPT_(_And<is_nothrow_copy_assignable<_Tp>...>::value) {
837    std::__memberwise_copy_assign(*this, __tuple, typename __make_tuple_indices<sizeof...(_Tp)>::type());
838    return *this;
839  }
840
841#  if _LIBCPP_STD_VER >= 23
842  _LIBCPP_HIDE_FROM_ABI constexpr const tuple& operator=(tuple const& __tuple) const
843    requires(_And<is_copy_assignable<const _Tp>...>::value)
844  {
845    std::__memberwise_copy_assign(*this, __tuple, typename __make_tuple_indices<sizeof...(_Tp)>::type());
846    return *this;
847  }
848
849  _LIBCPP_HIDE_FROM_ABI constexpr const tuple& operator=(tuple&& __tuple) const
850    requires(_And<is_assignable<const _Tp&, _Tp>...>::value)
851  {
852    std::__memberwise_forward_assign(
853        *this, std::move(__tuple), __tuple_types<_Tp...>(), typename __make_tuple_indices<sizeof...(_Tp)>::type());
854    return *this;
855  }
856#  endif // _LIBCPP_STD_VER >= 23
857
858  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple&
859  operator=(_If<_And<is_move_assignable<_Tp>...>::value, tuple, __nat>&& __tuple)
860      _NOEXCEPT_(_And<is_nothrow_move_assignable<_Tp>...>::value) {
861    std::__memberwise_forward_assign(
862        *this, std::move(__tuple), __tuple_types<_Tp...>(), typename __make_tuple_indices<sizeof...(_Tp)>::type());
863    return *this;
864  }
865
866  template <
867      class... _Up,
868      __enable_if_t< _And< _BoolConstant<sizeof...(_Tp) == sizeof...(_Up)>, is_assignable<_Tp&, _Up const&>... >::value,
869                     int> = 0>
870  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple& operator=(tuple<_Up...> const& __tuple)
871      _NOEXCEPT_(_And<is_nothrow_assignable<_Tp&, _Up const&>...>::value) {
872    std::__memberwise_copy_assign(*this, __tuple, typename __make_tuple_indices<sizeof...(_Tp)>::type());
873    return *this;
874  }
875
876  template <class... _Up,
877            __enable_if_t< _And< _BoolConstant<sizeof...(_Tp) == sizeof...(_Up)>, is_assignable<_Tp&, _Up>... >::value,
878                           int> = 0>
879  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple& operator=(tuple<_Up...>&& __tuple)
880      _NOEXCEPT_(_And<is_nothrow_assignable<_Tp&, _Up>...>::value) {
881    std::__memberwise_forward_assign(
882        *this, std::move(__tuple), __tuple_types<_Up...>(), typename __make_tuple_indices<sizeof...(_Tp)>::type());
883    return *this;
884  }
885
886#  if _LIBCPP_STD_VER >= 23
887  template <class... _UTypes,
888            enable_if_t< _And<_BoolConstant<sizeof...(_Tp) == sizeof...(_UTypes)>,
889                              is_assignable<const _Tp&, const _UTypes&>...>::value>* = nullptr>
890  _LIBCPP_HIDE_FROM_ABI constexpr const tuple& operator=(const tuple<_UTypes...>& __u) const {
891    std::__memberwise_copy_assign(*this, __u, typename __make_tuple_indices<sizeof...(_Tp)>::type());
892    return *this;
893  }
894
895  template <class... _UTypes,
896            enable_if_t< _And<_BoolConstant<sizeof...(_Tp) == sizeof...(_UTypes)>,
897                              is_assignable<const _Tp&, _UTypes>...>::value>* = nullptr>
898  _LIBCPP_HIDE_FROM_ABI constexpr const tuple& operator=(tuple<_UTypes...>&& __u) const {
899    std::__memberwise_forward_assign(
900        *this, __u, __tuple_types<_UTypes...>(), typename __make_tuple_indices<sizeof...(_Tp)>::type());
901    return *this;
902  }
903#  endif // _LIBCPP_STD_VER >= 23
904
905  template <template <class...> class _Pred,
906            bool _Const,
907            class _Pair,
908            class _DecayedPair = __remove_cvref_t<_Pair>,
909            class _Tuple       = tuple>
910  struct _AssignPredicateFromPair : false_type {};
911
912  template <template <class...> class _Pred, bool _Const, class _Pair, class _Up1, class _Up2, class _Tp1, class _Tp2>
913  struct _AssignPredicateFromPair<_Pred, _Const, _Pair, pair<_Up1, _Up2>, tuple<_Tp1, _Tp2> >
914      : _And<_Pred<__maybe_const<_Const, _Tp1>&, __copy_cvref_t<_Pair, _Up1> >,
915             _Pred<__maybe_const<_Const, _Tp2>&, __copy_cvref_t<_Pair, _Up2> > > {};
916
917  template <bool _Const, class _Pair>
918  struct _EnableAssignFromPair : _AssignPredicateFromPair<is_assignable, _Const, _Pair> {};
919
920  template <bool _Const, class _Pair>
921  struct _NothrowAssignFromPair : _AssignPredicateFromPair<is_nothrow_assignable, _Const, _Pair> {};
922
923#  if _LIBCPP_STD_VER >= 23
924  template <class _U1, class _U2, enable_if_t< _EnableAssignFromPair<true, const pair<_U1, _U2>&>::value>* = nullptr>
925  _LIBCPP_HIDE_FROM_ABI constexpr const tuple& operator=(const pair<_U1, _U2>& __pair) const
926      noexcept(_NothrowAssignFromPair<true, const pair<_U1, _U2>&>::value) {
927    std::get<0>(*this) = __pair.first;
928    std::get<1>(*this) = __pair.second;
929    return *this;
930  }
931
932  template <class _U1, class _U2, enable_if_t< _EnableAssignFromPair<true, pair<_U1, _U2>&&>::value>* = nullptr>
933  _LIBCPP_HIDE_FROM_ABI constexpr const tuple& operator=(pair<_U1, _U2>&& __pair) const
934      noexcept(_NothrowAssignFromPair<true, pair<_U1, _U2>&&>::value) {
935    std::get<0>(*this) = std::move(__pair.first);
936    std::get<1>(*this) = std::move(__pair.second);
937    return *this;
938  }
939#  endif // _LIBCPP_STD_VER >= 23
940
941  template <class _Up1,
942            class _Up2,
943            __enable_if_t< _EnableAssignFromPair<false, pair<_Up1, _Up2> const&>::value, int> = 0>
944  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple& operator=(pair<_Up1, _Up2> const& __pair)
945      _NOEXCEPT_(_NothrowAssignFromPair<false, pair<_Up1, _Up2> const&>::value) {
946    std::get<0>(*this) = __pair.first;
947    std::get<1>(*this) = __pair.second;
948    return *this;
949  }
950
951  template <class _Up1, class _Up2, __enable_if_t< _EnableAssignFromPair<false, pair<_Up1, _Up2>&&>::value, int> = 0>
952  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple& operator=(pair<_Up1, _Up2>&& __pair)
953      _NOEXCEPT_(_NothrowAssignFromPair<false, pair<_Up1, _Up2>&&>::value) {
954    std::get<0>(*this) = std::forward<_Up1>(__pair.first);
955    std::get<1>(*this) = std::forward<_Up2>(__pair.second);
956    return *this;
957  }
958
959  // EXTENSION
960  template <
961      class _Up,
962      size_t _Np,
963      __enable_if_t< _And< _BoolConstant<_Np == sizeof...(_Tp)>, is_assignable<_Tp&, _Up const&>... >::value, int> = 0>
964  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple& operator=(array<_Up, _Np> const& __array)
965      _NOEXCEPT_(_And<is_nothrow_assignable<_Tp&, _Up const&>...>::value) {
966    std::__memberwise_copy_assign(*this, __array, typename __make_tuple_indices<sizeof...(_Tp)>::type());
967    return *this;
968  }
969
970  // EXTENSION
971  template <class _Up,
972            size_t _Np,
973            class = void,
974            __enable_if_t< _And< _BoolConstant<_Np == sizeof...(_Tp)>, is_assignable<_Tp&, _Up>... >::value, int> = 0>
975  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple& operator=(array<_Up, _Np>&& __array)
976      _NOEXCEPT_(_And<is_nothrow_assignable<_Tp&, _Up>...>::value) {
977    std::__memberwise_forward_assign(
978        *this,
979        std::move(__array),
980        __tuple_types<_If<true, _Up, _Tp>...>(),
981        typename __make_tuple_indices<sizeof...(_Tp)>::type());
982    return *this;
983  }
984
985  // [tuple.swap]
986  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void swap(tuple& __t)
987      _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value) {
988    __base_.swap(__t.__base_);
989  }
990
991#  if _LIBCPP_STD_VER >= 23
992  _LIBCPP_HIDE_FROM_ABI constexpr void swap(const tuple& __t) const
993      noexcept(__all<is_nothrow_swappable_v<const _Tp&>...>::value) {
994    __base_.swap(__t.__base_);
995  }
996#  endif // _LIBCPP_STD_VER >= 23
997};
998
999template <>
1000class _LIBCPP_TEMPLATE_VIS tuple<> {
1001public:
1002  constexpr tuple() _NOEXCEPT = default;
1003  template <class _Alloc>
1004  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple(allocator_arg_t, const _Alloc&) _NOEXCEPT {}
1005  template <class _Alloc>
1006  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple(allocator_arg_t, const _Alloc&, const tuple&) _NOEXCEPT {}
1007  template <class _Up>
1008  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple(array<_Up, 0>) _NOEXCEPT {}
1009  template <class _Alloc, class _Up>
1010  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 tuple(allocator_arg_t, const _Alloc&, array<_Up, 0>) _NOEXCEPT {}
1011  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void swap(tuple&) _NOEXCEPT {}
1012#  if _LIBCPP_STD_VER >= 23
1013  _LIBCPP_HIDE_FROM_ABI constexpr void swap(const tuple&) const noexcept {}
1014#  endif
1015};
1016
1017#  if _LIBCPP_STD_VER >= 23
1018template <class... _TTypes, class... _UTypes, template <class> class _TQual, template <class> class _UQual>
1019  requires requires { typename tuple<common_reference_t<_TQual<_TTypes>, _UQual<_UTypes>>...>; }
1020struct basic_common_reference<tuple<_TTypes...>, tuple<_UTypes...>, _TQual, _UQual> {
1021  using type = tuple<common_reference_t<_TQual<_TTypes>, _UQual<_UTypes>>...>;
1022};
1023
1024template <class... _TTypes, class... _UTypes>
1025  requires requires { typename tuple<common_type_t<_TTypes, _UTypes>...>; }
1026struct common_type<tuple<_TTypes...>, tuple<_UTypes...>> {
1027  using type = tuple<common_type_t<_TTypes, _UTypes>...>;
1028};
1029#  endif // _LIBCPP_STD_VER >= 23
1030
1031#  if _LIBCPP_STD_VER >= 17
1032template <class... _Tp>
1033tuple(_Tp...) -> tuple<_Tp...>;
1034template <class _Tp1, class _Tp2>
1035tuple(pair<_Tp1, _Tp2>) -> tuple<_Tp1, _Tp2>;
1036template <class _Alloc, class... _Tp>
1037tuple(allocator_arg_t, _Alloc, _Tp...) -> tuple<_Tp...>;
1038template <class _Alloc, class _Tp1, class _Tp2>
1039tuple(allocator_arg_t, _Alloc, pair<_Tp1, _Tp2>) -> tuple<_Tp1, _Tp2>;
1040template <class _Alloc, class... _Tp>
1041tuple(allocator_arg_t, _Alloc, tuple<_Tp...>) -> tuple<_Tp...>;
1042#  endif
1043
1044template <class... _Tp, __enable_if_t<__all<__is_swappable<_Tp>::value...>::value, int> = 0>
1045inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void swap(tuple<_Tp...>& __t, tuple<_Tp...>& __u)
1046    _NOEXCEPT_(__all<__is_nothrow_swappable<_Tp>::value...>::value) {
1047  __t.swap(__u);
1048}
1049
1050#  if _LIBCPP_STD_VER >= 23
1051template <class... _Tp>
1052_LIBCPP_HIDE_FROM_ABI constexpr enable_if_t<__all<is_swappable_v<const _Tp>...>::value, void>
1053swap(const tuple<_Tp...>& __lhs,
1054     const tuple<_Tp...>& __rhs) noexcept(__all<is_nothrow_swappable_v<const _Tp>...>::value) {
1055  __lhs.swap(__rhs);
1056}
1057#  endif
1058
1059// get
1060
1061template <size_t _Ip, class... _Tp>
1062inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 typename tuple_element<_Ip, tuple<_Tp...> >::type&
1063get(tuple<_Tp...>& __t) _NOEXCEPT {
1064  typedef _LIBCPP_NODEBUG typename tuple_element<_Ip, tuple<_Tp...> >::type type;
1065  return static_cast<__tuple_leaf<_Ip, type>&>(__t.__base_).get();
1066}
1067
1068template <size_t _Ip, class... _Tp>
1069inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const typename tuple_element<_Ip, tuple<_Tp...> >::type&
1070get(const tuple<_Tp...>& __t) _NOEXCEPT {
1071  typedef _LIBCPP_NODEBUG typename tuple_element<_Ip, tuple<_Tp...> >::type type;
1072  return static_cast<const __tuple_leaf<_Ip, type>&>(__t.__base_).get();
1073}
1074
1075template <size_t _Ip, class... _Tp>
1076inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 typename tuple_element<_Ip, tuple<_Tp...> >::type&&
1077get(tuple<_Tp...>&& __t) _NOEXCEPT {
1078  typedef _LIBCPP_NODEBUG typename tuple_element<_Ip, tuple<_Tp...> >::type type;
1079  return static_cast<type&&>(static_cast<__tuple_leaf<_Ip, type>&&>(__t.__base_).get());
1080}
1081
1082template <size_t _Ip, class... _Tp>
1083inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const typename tuple_element<_Ip, tuple<_Tp...> >::type&&
1084get(const tuple<_Tp...>&& __t) _NOEXCEPT {
1085  typedef _LIBCPP_NODEBUG typename tuple_element<_Ip, tuple<_Tp...> >::type type;
1086  return static_cast<const type&&>(static_cast<const __tuple_leaf<_Ip, type>&&>(__t.__base_).get());
1087}
1088
1089#  if _LIBCPP_STD_VER >= 14
1090
1091template <class _T1, class... _Args>
1092inline _LIBCPP_HIDE_FROM_ABI constexpr _T1& get(tuple<_Args...>& __tup) noexcept {
1093  return std::get<__find_exactly_one_t<_T1, _Args...>::value>(__tup);
1094}
1095
1096template <class _T1, class... _Args>
1097inline _LIBCPP_HIDE_FROM_ABI constexpr _T1 const& get(tuple<_Args...> const& __tup) noexcept {
1098  return std::get<__find_exactly_one_t<_T1, _Args...>::value>(__tup);
1099}
1100
1101template <class _T1, class... _Args>
1102inline _LIBCPP_HIDE_FROM_ABI constexpr _T1&& get(tuple<_Args...>&& __tup) noexcept {
1103  return std::get<__find_exactly_one_t<_T1, _Args...>::value>(std::move(__tup));
1104}
1105
1106template <class _T1, class... _Args>
1107inline _LIBCPP_HIDE_FROM_ABI constexpr _T1 const&& get(tuple<_Args...> const&& __tup) noexcept {
1108  return std::get<__find_exactly_one_t<_T1, _Args...>::value>(std::move(__tup));
1109}
1110
1111#  endif
1112
1113// tie
1114
1115template <class... _Tp>
1116inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 tuple<_Tp&...> tie(_Tp&... __t) _NOEXCEPT {
1117  return tuple<_Tp&...>(__t...);
1118}
1119
1120template <class _Up>
1121struct __ignore_t {
1122  template <class _Tp>
1123  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 const __ignore_t& operator=(_Tp&&) const {
1124    return *this;
1125  }
1126};
1127
1128#  if _LIBCPP_STD_VER >= 17
1129inline constexpr __ignore_t<unsigned char> ignore = __ignore_t<unsigned char>();
1130#  else
1131namespace {
1132constexpr __ignore_t<unsigned char> ignore = __ignore_t<unsigned char>();
1133} // namespace
1134#  endif
1135
1136template <class... _Tp>
1137inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 tuple<typename __unwrap_ref_decay<_Tp>::type...>
1138make_tuple(_Tp&&... __t) {
1139  return tuple<typename __unwrap_ref_decay<_Tp>::type...>(std::forward<_Tp>(__t)...);
1140}
1141
1142template <class... _Tp>
1143inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 tuple<_Tp&&...> forward_as_tuple(_Tp&&... __t) _NOEXCEPT {
1144  return tuple<_Tp&&...>(std::forward<_Tp>(__t)...);
1145}
1146
1147template <size_t _Ip>
1148struct __tuple_equal {
1149  template <class _Tp, class _Up>
1150  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool operator()(const _Tp& __x, const _Up& __y) {
1151    return __tuple_equal<_Ip - 1>()(__x, __y) && std::get<_Ip - 1>(__x) == std::get<_Ip - 1>(__y);
1152  }
1153};
1154
1155template <>
1156struct __tuple_equal<0> {
1157  template <class _Tp, class _Up>
1158  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool operator()(const _Tp&, const _Up&) {
1159    return true;
1160  }
1161};
1162
1163template <class... _Tp, class... _Up>
1164inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool
1165operator==(const tuple<_Tp...>& __x, const tuple<_Up...>& __y) {
1166  static_assert(sizeof...(_Tp) == sizeof...(_Up), "Can't compare tuples of different sizes");
1167  return __tuple_equal<sizeof...(_Tp)>()(__x, __y);
1168}
1169
1170#  if _LIBCPP_STD_VER >= 20
1171
1172// operator<=>
1173
1174template <class... _Tp, class... _Up, size_t... _Is>
1175_LIBCPP_HIDE_FROM_ABI constexpr auto
1176__tuple_compare_three_way(const tuple<_Tp...>& __x, const tuple<_Up...>& __y, index_sequence<_Is...>) {
1177  common_comparison_category_t<__synth_three_way_result<_Tp, _Up>...> __result = strong_ordering::equal;
1178  static_cast<void>(
1179      ((__result = std::__synth_three_way(std::get<_Is>(__x), std::get<_Is>(__y)), __result != 0) || ...));
1180  return __result;
1181}
1182
1183template <class... _Tp, class... _Up>
1184  requires(sizeof...(_Tp) == sizeof...(_Up))
1185_LIBCPP_HIDE_FROM_ABI constexpr common_comparison_category_t<__synth_three_way_result<_Tp, _Up>...>
1186operator<=>(const tuple<_Tp...>& __x, const tuple<_Up...>& __y) {
1187  return std::__tuple_compare_three_way(__x, __y, index_sequence_for<_Tp...>{});
1188}
1189
1190#  else // _LIBCPP_STD_VER >= 20
1191
1192template <class... _Tp, class... _Up>
1193inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool
1194operator!=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y) {
1195  return !(__x == __y);
1196}
1197
1198template <size_t _Ip>
1199struct __tuple_less {
1200  template <class _Tp, class _Up>
1201  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool operator()(const _Tp& __x, const _Up& __y) {
1202    const size_t __idx = tuple_size<_Tp>::value - _Ip;
1203    if (std::get<__idx>(__x) < std::get<__idx>(__y))
1204      return true;
1205    if (std::get<__idx>(__y) < std::get<__idx>(__x))
1206      return false;
1207    return __tuple_less<_Ip - 1>()(__x, __y);
1208  }
1209};
1210
1211template <>
1212struct __tuple_less<0> {
1213  template <class _Tp, class _Up>
1214  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool operator()(const _Tp&, const _Up&) {
1215    return false;
1216  }
1217};
1218
1219template <class... _Tp, class... _Up>
1220inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool
1221operator<(const tuple<_Tp...>& __x, const tuple<_Up...>& __y) {
1222  static_assert(sizeof...(_Tp) == sizeof...(_Up), "Can't compare tuples of different sizes");
1223  return __tuple_less<sizeof...(_Tp)>()(__x, __y);
1224}
1225
1226template <class... _Tp, class... _Up>
1227inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool
1228operator>(const tuple<_Tp...>& __x, const tuple<_Up...>& __y) {
1229  return __y < __x;
1230}
1231
1232template <class... _Tp, class... _Up>
1233inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool
1234operator>=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y) {
1235  return !(__x < __y);
1236}
1237
1238template <class... _Tp, class... _Up>
1239inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool
1240operator<=(const tuple<_Tp...>& __x, const tuple<_Up...>& __y) {
1241  return !(__y < __x);
1242}
1243
1244#  endif // _LIBCPP_STD_VER >= 20
1245
1246// tuple_cat
1247
1248template <class _Tp, class _Up>
1249struct __tuple_cat_type;
1250
1251template <class... _Ttypes, class... _Utypes>
1252struct __tuple_cat_type<tuple<_Ttypes...>, __tuple_types<_Utypes...> > {
1253  typedef _LIBCPP_NODEBUG tuple<_Ttypes..., _Utypes...> type;
1254};
1255
1256template <class _ResultTuple, bool _Is_Tuple0TupleLike, class... _Tuples>
1257struct __tuple_cat_return_1 {};
1258
1259template <class... _Types, class _Tuple0>
1260struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0> {
1261  using type _LIBCPP_NODEBUG =
1262      typename __tuple_cat_type< tuple<_Types...>,
1263                                 typename __make_tuple_types<__remove_cvref_t<_Tuple0> >::type >::type;
1264};
1265
1266template <class... _Types, class _Tuple0, class _Tuple1, class... _Tuples>
1267struct __tuple_cat_return_1<tuple<_Types...>, true, _Tuple0, _Tuple1, _Tuples...>
1268    : public __tuple_cat_return_1<
1269          typename __tuple_cat_type< tuple<_Types...>,
1270                                     typename __make_tuple_types<__remove_cvref_t<_Tuple0> >::type >::type,
1271          __tuple_like_ext<__libcpp_remove_reference_t<_Tuple1> >::value,
1272          _Tuple1,
1273          _Tuples...> {};
1274
1275template <class... _Tuples>
1276struct __tuple_cat_return;
1277
1278template <class _Tuple0, class... _Tuples>
1279struct __tuple_cat_return<_Tuple0, _Tuples...>
1280    : public __tuple_cat_return_1<tuple<>,
1281                                  __tuple_like_ext<__libcpp_remove_reference_t<_Tuple0> >::value,
1282                                  _Tuple0,
1283                                  _Tuples...> {};
1284
1285template <>
1286struct __tuple_cat_return<> {
1287  typedef _LIBCPP_NODEBUG tuple<> type;
1288};
1289
1290inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 tuple<> tuple_cat() { return tuple<>(); }
1291
1292template <class _Rp, class _Indices, class _Tuple0, class... _Tuples>
1293struct __tuple_cat_return_ref_imp;
1294
1295template <class... _Types, size_t... _I0, class _Tuple0>
1296struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>, _Tuple0> {
1297  typedef _LIBCPP_NODEBUG __libcpp_remove_reference_t<_Tuple0> _T0;
1298  typedef tuple<_Types..., __apply_cv_t<_Tuple0, typename tuple_element<_I0, _T0>::type>&&...> type;
1299};
1300
1301template <class... _Types, size_t... _I0, class _Tuple0, class _Tuple1, class... _Tuples>
1302struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>, _Tuple0, _Tuple1, _Tuples...>
1303    : public __tuple_cat_return_ref_imp<
1304          tuple<_Types...,
1305                __apply_cv_t<_Tuple0, typename tuple_element<_I0, __libcpp_remove_reference_t<_Tuple0>>::type>&&...>,
1306          typename __make_tuple_indices<tuple_size<__libcpp_remove_reference_t<_Tuple1> >::value>::type,
1307          _Tuple1,
1308          _Tuples...> {};
1309
1310template <class _Tuple0, class... _Tuples>
1311struct __tuple_cat_return_ref
1312    : public __tuple_cat_return_ref_imp<
1313          tuple<>,
1314          typename __make_tuple_indices< tuple_size<__libcpp_remove_reference_t<_Tuple0> >::value >::type,
1315          _Tuple0,
1316          _Tuples...> {};
1317
1318template <class _Types, class _I0, class _J0>
1319struct __tuple_cat;
1320
1321template <class... _Types, size_t... _I0, size_t... _J0>
1322struct __tuple_cat<tuple<_Types...>, __tuple_indices<_I0...>, __tuple_indices<_J0...> > {
1323  template <class _Tuple0>
1324  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
1325      typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&>::type
1326      operator()(tuple<_Types...> __t, _Tuple0&& __t0) {
1327    (void)__t; // avoid unused parameter warning on GCC when _I0 is empty
1328    return std::forward_as_tuple(
1329        std::forward<_Types>(std::get<_I0>(__t))..., std::get<_J0>(std::forward<_Tuple0>(__t0))...);
1330  }
1331
1332  template <class _Tuple0, class _Tuple1, class... _Tuples>
1333  _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
1334      typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&, _Tuple1&&, _Tuples&&...>::type
1335      operator()(tuple<_Types...> __t, _Tuple0&& __t0, _Tuple1&& __t1, _Tuples&&... __tpls) {
1336    (void)__t; // avoid unused parameter warning on GCC when _I0 is empty
1337    typedef _LIBCPP_NODEBUG __libcpp_remove_reference_t<_Tuple0> _T0;
1338    typedef _LIBCPP_NODEBUG __libcpp_remove_reference_t<_Tuple1> _T1;
1339    return __tuple_cat<tuple<_Types..., __apply_cv_t<_Tuple0, typename tuple_element<_J0, _T0>::type>&&...>,
1340                       typename __make_tuple_indices<sizeof...(_Types) + tuple_size<_T0>::value>::type,
1341                       typename __make_tuple_indices<tuple_size<_T1>::value>::type>()(
1342        std::forward_as_tuple(
1343            std::forward<_Types>(std::get<_I0>(__t))..., std::get<_J0>(std::forward<_Tuple0>(__t0))...),
1344        std::forward<_Tuple1>(__t1),
1345        std::forward<_Tuples>(__tpls)...);
1346  }
1347};
1348
1349template <class _Tuple0, class... _Tuples>
1350inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 typename __tuple_cat_return<_Tuple0, _Tuples...>::type
1351tuple_cat(_Tuple0&& __t0, _Tuples&&... __tpls) {
1352  typedef _LIBCPP_NODEBUG __libcpp_remove_reference_t<_Tuple0> _T0;
1353  return __tuple_cat<tuple<>, __tuple_indices<>, typename __make_tuple_indices<tuple_size<_T0>::value>::type>()(
1354      tuple<>(), std::forward<_Tuple0>(__t0), std::forward<_Tuples>(__tpls)...);
1355}
1356
1357template <class... _Tp, class _Alloc>
1358struct _LIBCPP_TEMPLATE_VIS uses_allocator<tuple<_Tp...>, _Alloc> : true_type {};
1359
1360template <class _T1, class _T2>
1361template <class... _Args1, class... _Args2, size_t... _I1, size_t... _I2>
1362inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_T1, _T2>::pair(
1363    piecewise_construct_t,
1364    tuple<_Args1...>& __first_args,
1365    tuple<_Args2...>& __second_args,
1366    __tuple_indices<_I1...>,
1367    __tuple_indices<_I2...>)
1368    : first(std::forward<_Args1>(std::get<_I1>(__first_args))...),
1369      second(std::forward<_Args2>(std::get<_I2>(__second_args))...) {}
1370
1371#  if _LIBCPP_STD_VER >= 17
1372template <class _Tp>
1373inline constexpr size_t tuple_size_v = tuple_size<_Tp>::value;
1374
1375#    define _LIBCPP_NOEXCEPT_RETURN(...)                                                                               \
1376      noexcept(noexcept(__VA_ARGS__)) { return __VA_ARGS__; }
1377
1378// The _LIBCPP_NOEXCEPT_RETURN macro breaks formatting.
1379// clang-format off
1380template <class _Fn, class _Tuple, size_t... _Id>
1381inline _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto)
1382__apply_tuple_impl(_Fn&& __f, _Tuple&& __t, __tuple_indices<_Id...>)
1383    _LIBCPP_NOEXCEPT_RETURN(std::__invoke(std::forward<_Fn>(__f), std::get<_Id>(std::forward<_Tuple>(__t))...))
1384
1385template <class _Fn, class _Tuple>
1386inline _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) apply(_Fn&& __f, _Tuple&& __t)
1387    _LIBCPP_NOEXCEPT_RETURN(std::__apply_tuple_impl(
1388        std::forward<_Fn>(__f),
1389        std::forward<_Tuple>(__t),
1390        typename __make_tuple_indices<tuple_size_v<remove_reference_t<_Tuple>>>::type{}))
1391
1392template <class _Tp, class _Tuple, size_t... _Idx>
1393inline _LIBCPP_HIDE_FROM_ABI constexpr _Tp __make_from_tuple_impl(_Tuple&& __t, __tuple_indices<_Idx...>)
1394    _LIBCPP_NOEXCEPT_RETURN(_Tp(std::get<_Idx>(std::forward<_Tuple>(__t))...))
1395
1396template <class _Tp, class _Tuple>
1397inline _LIBCPP_HIDE_FROM_ABI constexpr _Tp make_from_tuple(_Tuple&& __t)
1398    _LIBCPP_NOEXCEPT_RETURN(std::__make_from_tuple_impl<_Tp>(
1399        std::forward<_Tuple>(__t), typename __make_tuple_indices<tuple_size_v<remove_reference_t<_Tuple>>>::type{}))
1400
1401#    undef _LIBCPP_NOEXCEPT_RETURN
1402
1403#  endif // _LIBCPP_STD_VER >= 17
1404
1405#endif // !defined(_LIBCPP_CXX03_LANG)
1406
1407_LIBCPP_END_NAMESPACE_STD
1408
1409_LIBCPP_POP_MACROS
1410
1411// clang-format on
1412
1413#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
1414#  include <exception>
1415#  include <iosfwd>
1416#  include <new>
1417#  include <type_traits>
1418#  include <typeinfo>
1419#  include <utility>
1420#endif
1421
1422#endif // _LIBCPP_TUPLE
1423