3 // Copyright (C) 2007-2014 Free Software Foundation, Inc.
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
25 /** @file include/tuple
26 * This is a Standard C++ Library header.
29 #ifndef _GLIBCXX_TUPLE
30 #define _GLIBCXX_TUPLE 1
32 #pragma GCC system_header
34 #if __cplusplus < 201103L
35 # include <bits/c++0x_warning.h>
40 #include <bits/uses_allocator.h>
42 namespace std _GLIBCXX_VISIBILITY(default)
44 _GLIBCXX_BEGIN_NAMESPACE_VERSION
47 * @addtogroup utilities
51 // Adds a const reference to a non-reference type.
52 template<typename _Tp>
54 { typedef const _Tp& type; };
56 template<typename _Tp>
57 struct __add_c_ref<_Tp&>
58 { typedef _Tp& type; };
60 // Adds a reference to a non-reference type.
61 template<typename _Tp>
63 { typedef _Tp& type; };
65 template<typename _Tp>
66 struct __add_ref<_Tp&>
67 { typedef _Tp& type; };
69 // Adds an rvalue reference to a non-reference type.
70 template<typename _Tp>
72 { typedef _Tp&& type; };
74 template<typename _Tp>
75 struct __add_r_ref<_Tp&>
76 { typedef _Tp& type; };
78 template<std::size_t _Idx, typename _Head, bool _IsEmptyNotFinal>
81 template<std::size_t _Idx, typename _Head>
82 struct _Head_base<_Idx, _Head, true>
85 constexpr _Head_base()
88 constexpr _Head_base(const _Head& __h)
91 template<typename _UHead, typename = typename
92 enable_if<!is_convertible<_UHead,
93 __uses_alloc_base>::value>::type>
94 constexpr _Head_base(_UHead&& __h)
95 : _Head(std::forward<_UHead>(__h)) { }
97 _Head_base(__uses_alloc0)
100 template<typename _Alloc>
101 _Head_base(__uses_alloc1<_Alloc> __a)
102 : _Head(allocator_arg, *__a._M_a) { }
104 template<typename _Alloc>
105 _Head_base(__uses_alloc2<_Alloc> __a)
106 : _Head(*__a._M_a) { }
108 template<typename _UHead>
109 _Head_base(__uses_alloc0, _UHead&& __uhead)
110 : _Head(std::forward<_UHead>(__uhead)) { }
112 template<typename _Alloc, typename _UHead>
113 _Head_base(__uses_alloc1<_Alloc> __a, _UHead&& __uhead)
114 : _Head(allocator_arg, *__a._M_a, std::forward<_UHead>(__uhead)) { }
116 template<typename _Alloc, typename _UHead>
117 _Head_base(__uses_alloc2<_Alloc> __a, _UHead&& __uhead)
118 : _Head(std::forward<_UHead>(__uhead), *__a._M_a) { }
120 static constexpr _Head&
121 _M_head(_Head_base& __b) noexcept { return __b; }
123 static constexpr const _Head&
124 _M_head(const _Head_base& __b) noexcept { return __b; }
127 template<std::size_t _Idx, typename _Head>
128 struct _Head_base<_Idx, _Head, false>
130 constexpr _Head_base()
133 constexpr _Head_base(const _Head& __h)
134 : _M_head_impl(__h) { }
136 template<typename _UHead, typename = typename
137 enable_if<!is_convertible<_UHead,
138 __uses_alloc_base>::value>::type>
139 constexpr _Head_base(_UHead&& __h)
140 : _M_head_impl(std::forward<_UHead>(__h)) { }
142 _Head_base(__uses_alloc0)
145 template<typename _Alloc>
146 _Head_base(__uses_alloc1<_Alloc> __a)
147 : _M_head_impl(allocator_arg, *__a._M_a) { }
149 template<typename _Alloc>
150 _Head_base(__uses_alloc2<_Alloc> __a)
151 : _M_head_impl(*__a._M_a) { }
153 template<typename _UHead>
154 _Head_base(__uses_alloc0, _UHead&& __uhead)
155 : _M_head_impl(std::forward<_UHead>(__uhead)) { }
157 template<typename _Alloc, typename _UHead>
158 _Head_base(__uses_alloc1<_Alloc> __a, _UHead&& __uhead)
159 : _M_head_impl(allocator_arg, *__a._M_a, std::forward<_UHead>(__uhead))
162 template<typename _Alloc, typename _UHead>
163 _Head_base(__uses_alloc2<_Alloc> __a, _UHead&& __uhead)
164 : _M_head_impl(std::forward<_UHead>(__uhead), *__a._M_a) { }
166 static constexpr _Head&
167 _M_head(_Head_base& __b) noexcept { return __b._M_head_impl; }
169 static constexpr const _Head&
170 _M_head(const _Head_base& __b) noexcept { return __b._M_head_impl; }
176 * Contains the actual implementation of the @c tuple template, stored
177 * as a recursive inheritance hierarchy from the first element (most
178 * derived class) to the last (least derived class). The @c Idx
179 * parameter gives the 0-based index of the element stored at this
180 * point in the hierarchy; we use it to implement a constant-time
183 template<std::size_t _Idx, typename... _Elements>
187 * Zero-element tuple implementation. This is the basis case for the
188 * inheritance recursion.
190 template<std::size_t _Idx>
191 struct _Tuple_impl<_Idx>
193 template<std::size_t, typename...> friend class _Tuple_impl;
195 _Tuple_impl() = default;
197 template<typename _Alloc>
198 _Tuple_impl(allocator_arg_t, const _Alloc&) { }
200 template<typename _Alloc>
201 _Tuple_impl(allocator_arg_t, const _Alloc&, const _Tuple_impl&) { }
203 template<typename _Alloc>
204 _Tuple_impl(allocator_arg_t, const _Alloc&, _Tuple_impl&&) { }
207 void _M_swap(_Tuple_impl&) noexcept { /* no-op */ }
210 template<typename _Tp>
211 struct __is_empty_non_tuple : is_empty<_Tp> { };
213 // Using EBO for elements that are tuples causes ambiguous base errors.
214 template<typename _El0, typename... _El>
215 struct __is_empty_non_tuple<tuple<_El0, _El...>> : false_type { };
217 // Use the Empty Base-class Optimization for empty, non-final types.
218 template<typename _Tp>
219 using __empty_not_final
220 = typename conditional<__is_final(_Tp), false_type,
221 __is_empty_non_tuple<_Tp>>::type;
224 * Recursive tuple implementation. Here we store the @c Head element
225 * and derive from a @c Tuple_impl containing the remaining elements
226 * (which contains the @c Tail).
228 template<std::size_t _Idx, typename _Head, typename... _Tail>
229 struct _Tuple_impl<_Idx, _Head, _Tail...>
230 : public _Tuple_impl<_Idx + 1, _Tail...>,
231 private _Head_base<_Idx, _Head, __empty_not_final<_Head>::value>
233 template<std::size_t, typename...> friend class _Tuple_impl;
235 typedef _Tuple_impl<_Idx + 1, _Tail...> _Inherited;
236 typedef _Head_base<_Idx, _Head, __empty_not_final<_Head>::value> _Base;
238 static constexpr _Head&
239 _M_head(_Tuple_impl& __t) noexcept { return _Base::_M_head(__t); }
241 static constexpr const _Head&
242 _M_head(const _Tuple_impl& __t) noexcept { return _Base::_M_head(__t); }
244 static constexpr _Inherited&
245 _M_tail(_Tuple_impl& __t) noexcept { return __t; }
247 static constexpr const _Inherited&
248 _M_tail(const _Tuple_impl& __t) noexcept { return __t; }
250 constexpr _Tuple_impl()
251 : _Inherited(), _Base() { }
254 constexpr _Tuple_impl(const _Head& __head, const _Tail&... __tail)
255 : _Inherited(__tail...), _Base(__head) { }
257 template<typename _UHead, typename... _UTail, typename = typename
258 enable_if<sizeof...(_Tail) == sizeof...(_UTail)>::type>
260 constexpr _Tuple_impl(_UHead&& __head, _UTail&&... __tail)
261 : _Inherited(std::forward<_UTail>(__tail)...),
262 _Base(std::forward<_UHead>(__head)) { }
264 constexpr _Tuple_impl(const _Tuple_impl&) = default;
267 _Tuple_impl(_Tuple_impl&& __in)
268 noexcept(__and_<is_nothrow_move_constructible<_Head>,
269 is_nothrow_move_constructible<_Inherited>>::value)
270 : _Inherited(std::move(_M_tail(__in))),
271 _Base(std::forward<_Head>(_M_head(__in))) { }
273 template<typename... _UElements>
274 constexpr _Tuple_impl(const _Tuple_impl<_Idx, _UElements...>& __in)
275 : _Inherited(_Tuple_impl<_Idx, _UElements...>::_M_tail(__in)),
276 _Base(_Tuple_impl<_Idx, _UElements...>::_M_head(__in)) { }
278 template<typename _UHead, typename... _UTails>
279 constexpr _Tuple_impl(_Tuple_impl<_Idx, _UHead, _UTails...>&& __in)
280 : _Inherited(std::move
281 (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_tail(__in))),
282 _Base(std::forward<_UHead>
283 (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_head(__in))) { }
285 template<typename _Alloc>
286 _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a)
287 : _Inherited(__tag, __a),
288 _Base(__use_alloc<_Head>(__a)) { }
290 template<typename _Alloc>
291 _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
292 const _Head& __head, const _Tail&... __tail)
293 : _Inherited(__tag, __a, __tail...),
294 _Base(__use_alloc<_Head, _Alloc, _Head>(__a), __head) { }
296 template<typename _Alloc, typename _UHead, typename... _UTail,
297 typename = typename enable_if<sizeof...(_Tail)
298 == sizeof...(_UTail)>::type>
299 _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
300 _UHead&& __head, _UTail&&... __tail)
301 : _Inherited(__tag, __a, std::forward<_UTail>(__tail)...),
302 _Base(__use_alloc<_Head, _Alloc, _UHead>(__a),
303 std::forward<_UHead>(__head)) { }
305 template<typename _Alloc>
306 _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
307 const _Tuple_impl& __in)
308 : _Inherited(__tag, __a, _M_tail(__in)),
309 _Base(__use_alloc<_Head, _Alloc, _Head>(__a), _M_head(__in)) { }
311 template<typename _Alloc>
312 _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
314 : _Inherited(__tag, __a, std::move(_M_tail(__in))),
315 _Base(__use_alloc<_Head, _Alloc, _Head>(__a),
316 std::forward<_Head>(_M_head(__in))) { }
318 template<typename _Alloc, typename... _UElements>
319 _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
320 const _Tuple_impl<_Idx, _UElements...>& __in)
321 : _Inherited(__tag, __a,
322 _Tuple_impl<_Idx, _UElements...>::_M_tail(__in)),
323 _Base(__use_alloc<_Head, _Alloc, _Head>(__a),
324 _Tuple_impl<_Idx, _UElements...>::_M_head(__in)) { }
326 template<typename _Alloc, typename _UHead, typename... _UTails>
327 _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
328 _Tuple_impl<_Idx, _UHead, _UTails...>&& __in)
329 : _Inherited(__tag, __a, std::move
330 (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_tail(__in))),
331 _Base(__use_alloc<_Head, _Alloc, _UHead>(__a),
333 (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_head(__in))) { }
336 operator=(const _Tuple_impl& __in)
338 _M_head(*this) = _M_head(__in);
339 _M_tail(*this) = _M_tail(__in);
344 operator=(_Tuple_impl&& __in)
345 noexcept(__and_<is_nothrow_move_assignable<_Head>,
346 is_nothrow_move_assignable<_Inherited>>::value)
348 _M_head(*this) = std::forward<_Head>(_M_head(__in));
349 _M_tail(*this) = std::move(_M_tail(__in));
353 template<typename... _UElements>
355 operator=(const _Tuple_impl<_Idx, _UElements...>& __in)
357 _M_head(*this) = _Tuple_impl<_Idx, _UElements...>::_M_head(__in);
358 _M_tail(*this) = _Tuple_impl<_Idx, _UElements...>::_M_tail(__in);
362 template<typename _UHead, typename... _UTails>
364 operator=(_Tuple_impl<_Idx, _UHead, _UTails...>&& __in)
366 _M_head(*this) = std::forward<_UHead>
367 (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_head(__in));
368 _M_tail(*this) = std::move
369 (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_tail(__in));
375 _M_swap(_Tuple_impl& __in)
376 noexcept(noexcept(swap(std::declval<_Head&>(),
377 std::declval<_Head&>()))
378 && noexcept(_M_tail(__in)._M_swap(_M_tail(__in))))
381 swap(_M_head(*this), _M_head(__in));
382 _Inherited::_M_swap(_M_tail(__in));
386 /// Primary class template, tuple
387 template<typename... _Elements>
388 class tuple : public _Tuple_impl<0, _Elements...>
390 typedef _Tuple_impl<0, _Elements...> _Inherited;
397 constexpr tuple(const _Elements&... __elements)
398 : _Inherited(__elements...) { }
400 template<typename... _UElements, typename = typename
401 enable_if<__and_<is_convertible<_UElements,
402 _Elements>...>::value>::type>
404 constexpr tuple(_UElements&&... __elements)
405 : _Inherited(std::forward<_UElements>(__elements)...) { }
407 constexpr tuple(const tuple&) = default;
409 constexpr tuple(tuple&&) = default;
411 template<typename... _UElements, typename = typename
412 enable_if<__and_<is_convertible<const _UElements&,
413 _Elements>...>::value>::type>
414 constexpr tuple(const tuple<_UElements...>& __in)
415 : _Inherited(static_cast<const _Tuple_impl<0, _UElements...>&>(__in))
418 template<typename... _UElements, typename = typename
419 enable_if<__and_<is_convertible<_UElements,
420 _Elements>...>::value>::type>
421 constexpr tuple(tuple<_UElements...>&& __in)
422 : _Inherited(static_cast<_Tuple_impl<0, _UElements...>&&>(__in)) { }
424 // Allocator-extended constructors.
426 template<typename _Alloc>
427 tuple(allocator_arg_t __tag, const _Alloc& __a)
428 : _Inherited(__tag, __a) { }
430 template<typename _Alloc>
431 tuple(allocator_arg_t __tag, const _Alloc& __a,
432 const _Elements&... __elements)
433 : _Inherited(__tag, __a, __elements...) { }
435 template<typename _Alloc, typename... _UElements, typename = typename
436 enable_if<sizeof...(_UElements)
437 == sizeof...(_Elements)>::type>
438 tuple(allocator_arg_t __tag, const _Alloc& __a,
439 _UElements&&... __elements)
440 : _Inherited(__tag, __a, std::forward<_UElements>(__elements)...)
443 template<typename _Alloc>
444 tuple(allocator_arg_t __tag, const _Alloc& __a, const tuple& __in)
445 : _Inherited(__tag, __a, static_cast<const _Inherited&>(__in)) { }
447 template<typename _Alloc>
448 tuple(allocator_arg_t __tag, const _Alloc& __a, tuple&& __in)
449 : _Inherited(__tag, __a, static_cast<_Inherited&&>(__in)) { }
451 template<typename _Alloc, typename... _UElements, typename = typename
452 enable_if<sizeof...(_UElements)
453 == sizeof...(_Elements)>::type>
454 tuple(allocator_arg_t __tag, const _Alloc& __a,
455 const tuple<_UElements...>& __in)
456 : _Inherited(__tag, __a,
457 static_cast<const _Tuple_impl<0, _UElements...>&>(__in))
460 template<typename _Alloc, typename... _UElements, typename = typename
461 enable_if<sizeof...(_UElements)
462 == sizeof...(_Elements)>::type>
463 tuple(allocator_arg_t __tag, const _Alloc& __a,
464 tuple<_UElements...>&& __in)
465 : _Inherited(__tag, __a,
466 static_cast<_Tuple_impl<0, _UElements...>&&>(__in))
470 operator=(const tuple& __in)
472 static_cast<_Inherited&>(*this) = __in;
477 operator=(tuple&& __in)
478 noexcept(is_nothrow_move_assignable<_Inherited>::value)
480 static_cast<_Inherited&>(*this) = std::move(__in);
484 template<typename... _UElements, typename = typename
485 enable_if<sizeof...(_UElements)
486 == sizeof...(_Elements)>::type>
488 operator=(const tuple<_UElements...>& __in)
490 static_cast<_Inherited&>(*this) = __in;
494 template<typename... _UElements, typename = typename
495 enable_if<sizeof...(_UElements)
496 == sizeof...(_Elements)>::type>
498 operator=(tuple<_UElements...>&& __in)
500 static_cast<_Inherited&>(*this) = std::move(__in);
506 noexcept(noexcept(__in._M_swap(__in)))
507 { _Inherited::_M_swap(__in); }
510 // Explicit specialization, zero-element tuple.
515 void swap(tuple&) noexcept { /* no-op */ }
518 /// Partial specialization, 2-element tuple.
519 /// Includes construction and assignment from a pair.
520 template<typename _T1, typename _T2>
521 class tuple<_T1, _T2> : public _Tuple_impl<0, _T1, _T2>
523 typedef _Tuple_impl<0, _T1, _T2> _Inherited;
530 constexpr tuple(const _T1& __a1, const _T2& __a2)
531 : _Inherited(__a1, __a2) { }
533 template<typename _U1, typename _U2, typename = typename
534 enable_if<__and_<is_convertible<_U1, _T1>,
535 is_convertible<_U2, _T2>>::value>::type>
537 constexpr tuple(_U1&& __a1, _U2&& __a2)
538 : _Inherited(std::forward<_U1>(__a1), std::forward<_U2>(__a2)) { }
540 constexpr tuple(const tuple&) = default;
542 constexpr tuple(tuple&&) = default;
544 template<typename _U1, typename _U2, typename = typename
545 enable_if<__and_<is_convertible<const _U1&, _T1>,
546 is_convertible<const _U2&, _T2>>::value>::type>
547 constexpr tuple(const tuple<_U1, _U2>& __in)
548 : _Inherited(static_cast<const _Tuple_impl<0, _U1, _U2>&>(__in)) { }
550 template<typename _U1, typename _U2, typename = typename
551 enable_if<__and_<is_convertible<_U1, _T1>,
552 is_convertible<_U2, _T2>>::value>::type>
553 constexpr tuple(tuple<_U1, _U2>&& __in)
554 : _Inherited(static_cast<_Tuple_impl<0, _U1, _U2>&&>(__in)) { }
556 template<typename _U1, typename _U2, typename = typename
557 enable_if<__and_<is_convertible<const _U1&, _T1>,
558 is_convertible<const _U2&, _T2>>::value>::type>
559 constexpr tuple(const pair<_U1, _U2>& __in)
560 : _Inherited(__in.first, __in.second) { }
562 template<typename _U1, typename _U2, typename = typename
563 enable_if<__and_<is_convertible<_U1, _T1>,
564 is_convertible<_U2, _T2>>::value>::type>
565 constexpr tuple(pair<_U1, _U2>&& __in)
566 : _Inherited(std::forward<_U1>(__in.first),
567 std::forward<_U2>(__in.second)) { }
569 // Allocator-extended constructors.
571 template<typename _Alloc>
572 tuple(allocator_arg_t __tag, const _Alloc& __a)
573 : _Inherited(__tag, __a) { }
575 template<typename _Alloc>
576 tuple(allocator_arg_t __tag, const _Alloc& __a,
577 const _T1& __a1, const _T2& __a2)
578 : _Inherited(__tag, __a, __a1, __a2) { }
580 template<typename _Alloc, typename _U1, typename _U2>
581 tuple(allocator_arg_t __tag, const _Alloc& __a, _U1&& __a1, _U2&& __a2)
582 : _Inherited(__tag, __a, std::forward<_U1>(__a1),
583 std::forward<_U2>(__a2)) { }
585 template<typename _Alloc>
586 tuple(allocator_arg_t __tag, const _Alloc& __a, const tuple& __in)
587 : _Inherited(__tag, __a, static_cast<const _Inherited&>(__in)) { }
589 template<typename _Alloc>
590 tuple(allocator_arg_t __tag, const _Alloc& __a, tuple&& __in)
591 : _Inherited(__tag, __a, static_cast<_Inherited&&>(__in)) { }
593 template<typename _Alloc, typename _U1, typename _U2>
594 tuple(allocator_arg_t __tag, const _Alloc& __a,
595 const tuple<_U1, _U2>& __in)
596 : _Inherited(__tag, __a,
597 static_cast<const _Tuple_impl<0, _U1, _U2>&>(__in))
600 template<typename _Alloc, typename _U1, typename _U2>
601 tuple(allocator_arg_t __tag, const _Alloc& __a, tuple<_U1, _U2>&& __in)
602 : _Inherited(__tag, __a, static_cast<_Tuple_impl<0, _U1, _U2>&&>(__in))
605 template<typename _Alloc, typename _U1, typename _U2>
606 tuple(allocator_arg_t __tag, const _Alloc& __a,
607 const pair<_U1, _U2>& __in)
608 : _Inherited(__tag, __a, __in.first, __in.second) { }
610 template<typename _Alloc, typename _U1, typename _U2>
611 tuple(allocator_arg_t __tag, const _Alloc& __a, pair<_U1, _U2>&& __in)
612 : _Inherited(__tag, __a, std::forward<_U1>(__in.first),
613 std::forward<_U2>(__in.second)) { }
616 operator=(const tuple& __in)
618 static_cast<_Inherited&>(*this) = __in;
623 operator=(tuple&& __in)
624 noexcept(is_nothrow_move_assignable<_Inherited>::value)
626 static_cast<_Inherited&>(*this) = std::move(__in);
630 template<typename _U1, typename _U2>
632 operator=(const tuple<_U1, _U2>& __in)
634 static_cast<_Inherited&>(*this) = __in;
638 template<typename _U1, typename _U2>
640 operator=(tuple<_U1, _U2>&& __in)
642 static_cast<_Inherited&>(*this) = std::move(__in);
646 template<typename _U1, typename _U2>
648 operator=(const pair<_U1, _U2>& __in)
650 this->_M_head(*this) = __in.first;
651 this->_M_tail(*this)._M_head(*this) = __in.second;
655 template<typename _U1, typename _U2>
657 operator=(pair<_U1, _U2>&& __in)
659 this->_M_head(*this) = std::forward<_U1>(__in.first);
660 this->_M_tail(*this)._M_head(*this) = std::forward<_U2>(__in.second);
666 noexcept(noexcept(__in._M_swap(__in)))
667 { _Inherited::_M_swap(__in); }
671 /// Gives the type of the ith element of a given tuple type.
672 template<std::size_t __i, typename _Tp>
673 struct tuple_element;
676 * Recursive case for tuple_element: strip off the first element in
677 * the tuple and retrieve the (i-1)th element of the remaining tuple.
679 template<std::size_t __i, typename _Head, typename... _Tail>
680 struct tuple_element<__i, tuple<_Head, _Tail...> >
681 : tuple_element<__i - 1, tuple<_Tail...> > { };
684 * Basis case for tuple_element: The first element is the one we're seeking.
686 template<typename _Head, typename... _Tail>
687 struct tuple_element<0, tuple<_Head, _Tail...> >
692 template<std::size_t __i, typename _Tp>
693 struct tuple_element<__i, const _Tp>
696 add_const<typename tuple_element<__i, _Tp>::type>::type type;
699 template<std::size_t __i, typename _Tp>
700 struct tuple_element<__i, volatile _Tp>
703 add_volatile<typename tuple_element<__i, _Tp>::type>::type type;
706 template<std::size_t __i, typename _Tp>
707 struct tuple_element<__i, const volatile _Tp>
710 add_cv<typename tuple_element<__i, _Tp>::type>::type type;
713 #if __cplusplus > 201103L
714 template<std::size_t __i, typename _Tp>
715 using tuple_element_t = typename tuple_element<__i, _Tp>::type;
718 /// Finds the size of a given tuple type.
719 template<typename _Tp>
722 // _GLIBCXX_RESOLVE_LIB_DEFECTS
723 // 2313. tuple_size should always derive from integral_constant<size_t, N>
724 template<typename _Tp>
725 struct tuple_size<const _Tp>
726 : public integral_constant<size_t, tuple_size<_Tp>::value> { };
728 template<typename _Tp>
729 struct tuple_size<volatile _Tp>
730 : public integral_constant<size_t, tuple_size<_Tp>::value> { };
732 template<typename _Tp>
733 struct tuple_size<const volatile _Tp>
734 : public integral_constant<size_t, tuple_size<_Tp>::value> { };
737 template<typename... _Elements>
738 struct tuple_size<tuple<_Elements...>>
739 : public integral_constant<std::size_t, sizeof...(_Elements)> { };
741 template<std::size_t __i, typename _Head, typename... _Tail>
742 constexpr typename __add_ref<_Head>::type
743 __get_helper(_Tuple_impl<__i, _Head, _Tail...>& __t) noexcept
744 { return _Tuple_impl<__i, _Head, _Tail...>::_M_head(__t); }
746 template<std::size_t __i, typename _Head, typename... _Tail>
747 constexpr typename __add_c_ref<_Head>::type
748 __get_helper(const _Tuple_impl<__i, _Head, _Tail...>& __t) noexcept
749 { return _Tuple_impl<__i, _Head, _Tail...>::_M_head(__t); }
751 /// Return a reference to the ith element of a tuple.
752 template<std::size_t __i, typename... _Elements>
753 constexpr typename __add_ref<
754 typename tuple_element<__i, tuple<_Elements...>>::type
756 get(tuple<_Elements...>& __t) noexcept
757 { return std::__get_helper<__i>(__t); }
759 /// Return a const reference to the ith element of a const tuple.
760 template<std::size_t __i, typename... _Elements>
761 constexpr typename __add_c_ref<
762 typename tuple_element<__i, tuple<_Elements...>>::type
764 get(const tuple<_Elements...>& __t) noexcept
765 { return std::__get_helper<__i>(__t); }
767 /// Return an rvalue reference to the ith element of a tuple rvalue.
768 template<std::size_t __i, typename... _Elements>
769 constexpr typename __add_r_ref<
770 typename tuple_element<__i, tuple<_Elements...>>::type
772 get(tuple<_Elements...>&& __t) noexcept
773 { return std::forward<typename tuple_element<__i,
774 tuple<_Elements...>>::type&&>(get<__i>(__t)); }
776 #if __cplusplus > 201103L
778 #define __cpp_lib_tuples_by_type 201304
780 template<typename _Head, size_t __i, typename... _Tail>
781 constexpr typename __add_ref<_Head>::type
782 __get_helper2(_Tuple_impl<__i, _Head, _Tail...>& __t) noexcept
783 { return _Tuple_impl<__i, _Head, _Tail...>::_M_head(__t); }
785 template<typename _Head, size_t __i, typename... _Tail>
786 constexpr typename __add_c_ref<_Head>::type
787 __get_helper2(const _Tuple_impl<__i, _Head, _Tail...>& __t) noexcept
788 { return _Tuple_impl<__i, _Head, _Tail...>::_M_head(__t); }
790 /// Return a reference to the unique element of type _Tp of a tuple.
791 template <typename _Tp, typename... _Types>
793 get(tuple<_Types...>& __t) noexcept
794 { return std::__get_helper2<_Tp>(__t); }
796 /// Return a reference to the unique element of type _Tp of a tuple rvalue.
797 template <typename _Tp, typename... _Types>
799 get(tuple<_Types...>&& __t) noexcept
800 { return std::forward<_Tp&&>(std::__get_helper2<_Tp>(__t)); }
802 /// Return a const reference to the unique element of type _Tp of a tuple.
803 template <typename _Tp, typename... _Types>
805 get(const tuple<_Types...>& __t) noexcept
806 { return std::__get_helper2<_Tp>(__t); }
810 // This class helps construct the various comparison operations on tuples
811 template<std::size_t __check_equal_size, std::size_t __i, std::size_t __j,
812 typename _Tp, typename _Up>
813 struct __tuple_compare;
815 template<std::size_t __i, std::size_t __j, typename _Tp, typename _Up>
816 struct __tuple_compare<0, __i, __j, _Tp, _Up>
818 static constexpr bool
819 __eq(const _Tp& __t, const _Up& __u)
821 return (get<__i>(__t) == get<__i>(__u) &&
822 __tuple_compare<0, __i + 1, __j, _Tp, _Up>::__eq(__t, __u));
825 static constexpr bool
826 __less(const _Tp& __t, const _Up& __u)
828 return ((get<__i>(__t) < get<__i>(__u))
829 || !(get<__i>(__u) < get<__i>(__t)) &&
830 __tuple_compare<0, __i + 1, __j, _Tp, _Up>::__less(__t, __u));
834 template<std::size_t __i, typename _Tp, typename _Up>
835 struct __tuple_compare<0, __i, __i, _Tp, _Up>
837 static constexpr bool
838 __eq(const _Tp&, const _Up&) { return true; }
840 static constexpr bool
841 __less(const _Tp&, const _Up&) { return false; }
844 template<typename... _TElements, typename... _UElements>
846 operator==(const tuple<_TElements...>& __t,
847 const tuple<_UElements...>& __u)
849 typedef tuple<_TElements...> _Tp;
850 typedef tuple<_UElements...> _Up;
851 return bool(__tuple_compare<tuple_size<_Tp>::value - tuple_size<_Up>::value,
852 0, tuple_size<_Tp>::value, _Tp, _Up>::__eq(__t, __u));
855 template<typename... _TElements, typename... _UElements>
857 operator<(const tuple<_TElements...>& __t,
858 const tuple<_UElements...>& __u)
860 typedef tuple<_TElements...> _Tp;
861 typedef tuple<_UElements...> _Up;
862 return bool(__tuple_compare<tuple_size<_Tp>::value - tuple_size<_Up>::value,
863 0, tuple_size<_Tp>::value, _Tp, _Up>::__less(__t, __u));
866 template<typename... _TElements, typename... _UElements>
868 operator!=(const tuple<_TElements...>& __t,
869 const tuple<_UElements...>& __u)
870 { return !(__t == __u); }
872 template<typename... _TElements, typename... _UElements>
874 operator>(const tuple<_TElements...>& __t,
875 const tuple<_UElements...>& __u)
876 { return __u < __t; }
878 template<typename... _TElements, typename... _UElements>
880 operator<=(const tuple<_TElements...>& __t,
881 const tuple<_UElements...>& __u)
882 { return !(__u < __t); }
884 template<typename... _TElements, typename... _UElements>
886 operator>=(const tuple<_TElements...>& __t,
887 const tuple<_UElements...>& __u)
888 { return !(__t < __u); }
891 template<typename... _Elements>
892 constexpr tuple<typename __decay_and_strip<_Elements>::__type...>
893 make_tuple(_Elements&&... __args)
895 typedef tuple<typename __decay_and_strip<_Elements>::__type...>
897 return __result_type(std::forward<_Elements>(__args)...);
900 template<typename... _Elements>
901 tuple<_Elements&&...>
902 forward_as_tuple(_Elements&&... __args) noexcept
903 { return tuple<_Elements&&...>(std::forward<_Elements>(__args)...); }
906 struct __is_tuple_like_impl : false_type
909 template<typename... _Tps>
910 struct __is_tuple_like_impl<tuple<_Tps...>> : true_type
913 template<typename _T1, typename _T2>
914 struct __is_tuple_like_impl<pair<_T1, _T2>> : true_type
917 template<typename _Tp, std::size_t _Nm>
918 struct __is_tuple_like_impl<array<_Tp, _Nm>> : true_type
921 // Internal type trait that allows us to sfinae-protect tuple_cat.
922 template<typename _Tp>
923 struct __is_tuple_like
924 : public __is_tuple_like_impl<typename std::remove_cv
925 <typename std::remove_reference<_Tp>::type>::type>::type
928 template<std::size_t, typename, typename, std::size_t>
929 struct __make_tuple_impl;
931 template<std::size_t _Idx, typename _Tuple, typename... _Tp,
933 struct __make_tuple_impl<_Idx, tuple<_Tp...>, _Tuple, _Nm>
935 typedef typename __make_tuple_impl<_Idx + 1, tuple<_Tp...,
936 typename std::tuple_element<_Idx, _Tuple>::type>, _Tuple, _Nm>::__type
940 template<std::size_t _Nm, typename _Tuple, typename... _Tp>
941 struct __make_tuple_impl<_Nm, tuple<_Tp...>, _Tuple, _Nm>
943 typedef tuple<_Tp...> __type;
946 template<typename _Tuple>
947 struct __do_make_tuple
948 : public __make_tuple_impl<0, tuple<>, _Tuple,
949 std::tuple_size<_Tuple>::value>
952 // Returns the std::tuple equivalent of a tuple-like type.
953 template<typename _Tuple>
955 : public __do_make_tuple<typename std::remove_cv
956 <typename std::remove_reference<_Tuple>::type>::type>
959 // Combines several std::tuple's into a single one.
960 template<typename...>
961 struct __combine_tuples;
964 struct __combine_tuples<>
966 typedef tuple<> __type;
969 template<typename... _Ts>
970 struct __combine_tuples<tuple<_Ts...>>
972 typedef tuple<_Ts...> __type;
975 template<typename... _T1s, typename... _T2s, typename... _Rem>
976 struct __combine_tuples<tuple<_T1s...>, tuple<_T2s...>, _Rem...>
978 typedef typename __combine_tuples<tuple<_T1s..., _T2s...>,
979 _Rem...>::__type __type;
982 // Computes the result type of tuple_cat given a set of tuple-like types.
983 template<typename... _Tpls>
984 struct __tuple_cat_result
986 typedef typename __combine_tuples
987 <typename __make_tuple<_Tpls>::__type...>::__type __type;
990 // Helper to determine the index set for the first tuple-like
991 // type of a given set.
992 template<typename...>
993 struct __make_1st_indices;
996 struct __make_1st_indices<>
998 typedef std::_Index_tuple<> __type;
1001 template<typename _Tp, typename... _Tpls>
1002 struct __make_1st_indices<_Tp, _Tpls...>
1004 typedef typename std::_Build_index_tuple<std::tuple_size<
1005 typename std::remove_reference<_Tp>::type>::value>::__type __type;
1008 // Performs the actual concatenation by step-wise expanding tuple-like
1009 // objects into the elements, which are finally forwarded into the
1011 template<typename _Ret, typename _Indices, typename... _Tpls>
1012 struct __tuple_concater;
1014 template<typename _Ret, std::size_t... _Is, typename _Tp, typename... _Tpls>
1015 struct __tuple_concater<_Ret, std::_Index_tuple<_Is...>, _Tp, _Tpls...>
1017 template<typename... _Us>
1018 static constexpr _Ret
1019 _S_do(_Tp&& __tp, _Tpls&&... __tps, _Us&&... __us)
1021 typedef typename __make_1st_indices<_Tpls...>::__type __idx;
1022 typedef __tuple_concater<_Ret, __idx, _Tpls...> __next;
1023 return __next::_S_do(std::forward<_Tpls>(__tps)...,
1024 std::forward<_Us>(__us)...,
1025 std::get<_Is>(std::forward<_Tp>(__tp))...);
1029 template<typename _Ret>
1030 struct __tuple_concater<_Ret, std::_Index_tuple<>>
1032 template<typename... _Us>
1033 static constexpr _Ret
1034 _S_do(_Us&&... __us)
1036 return _Ret(std::forward<_Us>(__us)...);
1041 template<typename... _Tpls, typename = typename
1042 enable_if<__and_<__is_tuple_like<_Tpls>...>::value>::type>
1044 tuple_cat(_Tpls&&... __tpls)
1045 -> typename __tuple_cat_result<_Tpls...>::__type
1047 typedef typename __tuple_cat_result<_Tpls...>::__type __ret;
1048 typedef typename __make_1st_indices<_Tpls...>::__type __idx;
1049 typedef __tuple_concater<__ret, __idx, _Tpls...> __concater;
1050 return __concater::_S_do(std::forward<_Tpls>(__tpls)...);
1054 template<typename... _Elements>
1055 inline tuple<_Elements&...>
1056 tie(_Elements&... __args) noexcept
1057 { return tuple<_Elements&...>(__args...); }
1060 template<typename... _Elements>
1062 swap(tuple<_Elements...>& __x, tuple<_Elements...>& __y)
1063 noexcept(noexcept(__x.swap(__y)))
1066 // A class (and instance) which can be used in 'tie' when an element
1067 // of a tuple is not required
1068 struct _Swallow_assign
1071 const _Swallow_assign&
1072 operator=(const _Tp&) const
1076 const _Swallow_assign ignore{};
1078 /// Partial specialization for tuples
1079 template<typename... _Types, typename _Alloc>
1080 struct uses_allocator<tuple<_Types...>, _Alloc> : true_type { };
1082 // See stl_pair.h...
1083 template<class _T1, class _T2>
1084 template<typename... _Args1, typename... _Args2>
1087 pair(piecewise_construct_t,
1088 tuple<_Args1...> __first, tuple<_Args2...> __second)
1089 : pair(__first, __second,
1090 typename _Build_index_tuple<sizeof...(_Args1)>::__type(),
1091 typename _Build_index_tuple<sizeof...(_Args2)>::__type())
1094 template<class _T1, class _T2>
1095 template<typename... _Args1, std::size_t... _Indexes1,
1096 typename... _Args2, std::size_t... _Indexes2>
1099 pair(tuple<_Args1...>& __tuple1, tuple<_Args2...>& __tuple2,
1100 _Index_tuple<_Indexes1...>, _Index_tuple<_Indexes2...>)
1101 : first(std::forward<_Args1>(std::get<_Indexes1>(__tuple1))...),
1102 second(std::forward<_Args2>(std::get<_Indexes2>(__tuple2))...)
1107 _GLIBCXX_END_NAMESPACE_VERSION
1112 #endif // _GLIBCXX_TUPLE