libstdc++
tuple
1 // <tuple> -*- C++ -*-
2 
3 // Copyright (C) 2007-2014 Free Software Foundation, Inc.
4 //
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)
9 // any later version.
10 
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.
15 
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.
19 
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/>.
24 
25 /** @file include/tuple
26  * This is a Standard C++ Library header.
27  */
28 
29 #ifndef _GLIBCXX_TUPLE
30 #define _GLIBCXX_TUPLE 1
31 
32 #pragma GCC system_header
33 
34 #if __cplusplus < 201103L
35 # include <bits/c++0x_warning.h>
36 #else
37 
38 #include <utility>
39 #include <array>
40 #include <bits/uses_allocator.h>
41 
42 namespace std _GLIBCXX_VISIBILITY(default)
43 {
44 _GLIBCXX_BEGIN_NAMESPACE_VERSION
45 
46  /**
47  * @addtogroup utilities
48  * @{
49  */
50 
51  // Adds a const reference to a non-reference type.
52  template<typename _Tp>
53  struct __add_c_ref
54  { typedef const _Tp& type; };
55 
56  template<typename _Tp>
57  struct __add_c_ref<_Tp&>
58  { typedef _Tp& type; };
59 
60  // Adds a reference to a non-reference type.
61  template<typename _Tp>
62  struct __add_ref
63  { typedef _Tp& type; };
64 
65  template<typename _Tp>
66  struct __add_ref<_Tp&>
67  { typedef _Tp& type; };
68 
69  // Adds an rvalue reference to a non-reference type.
70  template<typename _Tp>
71  struct __add_r_ref
72  { typedef _Tp&& type; };
73 
74  template<typename _Tp>
75  struct __add_r_ref<_Tp&>
76  { typedef _Tp& type; };
77 
78  template<std::size_t _Idx, typename _Head, bool _IsEmptyNotFinal>
79  struct _Head_base;
80 
81  template<std::size_t _Idx, typename _Head>
82  struct _Head_base<_Idx, _Head, true>
83  : public _Head
84  {
85  constexpr _Head_base()
86  : _Head() { }
87 
88  constexpr _Head_base(const _Head& __h)
89  : _Head(__h) { }
90 
91  constexpr _Head_base(const _Head_base&) = default;
92  constexpr _Head_base(_Head_base&&) = default;
93 
94  template<typename _UHead>
95  constexpr _Head_base(_UHead&& __h)
96  : _Head(std::forward<_UHead>(__h)) { }
97 
98  _Head_base(allocator_arg_t, __uses_alloc0)
99  : _Head() { }
100 
101  template<typename _Alloc>
102  _Head_base(allocator_arg_t, __uses_alloc1<_Alloc> __a)
103  : _Head(allocator_arg, *__a._M_a) { }
104 
105  template<typename _Alloc>
106  _Head_base(allocator_arg_t, __uses_alloc2<_Alloc> __a)
107  : _Head(*__a._M_a) { }
108 
109  template<typename _UHead>
110  _Head_base(__uses_alloc0, _UHead&& __uhead)
111  : _Head(std::forward<_UHead>(__uhead)) { }
112 
113  template<typename _Alloc, typename _UHead>
114  _Head_base(__uses_alloc1<_Alloc> __a, _UHead&& __uhead)
115  : _Head(allocator_arg, *__a._M_a, std::forward<_UHead>(__uhead)) { }
116 
117  template<typename _Alloc, typename _UHead>
118  _Head_base(__uses_alloc2<_Alloc> __a, _UHead&& __uhead)
119  : _Head(std::forward<_UHead>(__uhead), *__a._M_a) { }
120 
121  static constexpr _Head&
122  _M_head(_Head_base& __b) noexcept { return __b; }
123 
124  static constexpr const _Head&
125  _M_head(const _Head_base& __b) noexcept { return __b; }
126  };
127 
128  template<std::size_t _Idx, typename _Head>
129  struct _Head_base<_Idx, _Head, false>
130  {
131  constexpr _Head_base()
132  : _M_head_impl() { }
133 
134  constexpr _Head_base(const _Head& __h)
135  : _M_head_impl(__h) { }
136 
137  constexpr _Head_base(const _Head_base&) = default;
138  constexpr _Head_base(_Head_base&&) = default;
139 
140  template<typename _UHead>
141  constexpr _Head_base(_UHead&& __h)
142  : _M_head_impl(std::forward<_UHead>(__h)) { }
143 
144  _Head_base(allocator_arg_t, __uses_alloc0)
145  : _M_head_impl() { }
146 
147  template<typename _Alloc>
148  _Head_base(allocator_arg_t, __uses_alloc1<_Alloc> __a)
149  : _M_head_impl(allocator_arg, *__a._M_a) { }
150 
151  template<typename _Alloc>
152  _Head_base(allocator_arg_t, __uses_alloc2<_Alloc> __a)
153  : _M_head_impl(*__a._M_a) { }
154 
155  template<typename _UHead>
156  _Head_base(__uses_alloc0, _UHead&& __uhead)
157  : _M_head_impl(std::forward<_UHead>(__uhead)) { }
158 
159  template<typename _Alloc, typename _UHead>
160  _Head_base(__uses_alloc1<_Alloc> __a, _UHead&& __uhead)
161  : _M_head_impl(allocator_arg, *__a._M_a, std::forward<_UHead>(__uhead))
162  { }
163 
164  template<typename _Alloc, typename _UHead>
165  _Head_base(__uses_alloc2<_Alloc> __a, _UHead&& __uhead)
166  : _M_head_impl(std::forward<_UHead>(__uhead), *__a._M_a) { }
167 
168  static constexpr _Head&
169  _M_head(_Head_base& __b) noexcept { return __b._M_head_impl; }
170 
171  static constexpr const _Head&
172  _M_head(const _Head_base& __b) noexcept { return __b._M_head_impl; }
173 
174  _Head _M_head_impl;
175  };
176 
177  /**
178  * Contains the actual implementation of the @c tuple template, stored
179  * as a recursive inheritance hierarchy from the first element (most
180  * derived class) to the last (least derived class). The @c Idx
181  * parameter gives the 0-based index of the element stored at this
182  * point in the hierarchy; we use it to implement a constant-time
183  * get() operation.
184  */
185  template<std::size_t _Idx, typename... _Elements>
186  struct _Tuple_impl;
187 
188  /**
189  * Zero-element tuple implementation. This is the basis case for the
190  * inheritance recursion.
191  */
192  template<std::size_t _Idx>
193  struct _Tuple_impl<_Idx>
194  {
195  template<std::size_t, typename...> friend class _Tuple_impl;
196 
197  _Tuple_impl() = default;
198 
199  template<typename _Alloc>
200  _Tuple_impl(allocator_arg_t, const _Alloc&) { }
201 
202  template<typename _Alloc>
203  _Tuple_impl(allocator_arg_t, const _Alloc&, const _Tuple_impl&) { }
204 
205  template<typename _Alloc>
206  _Tuple_impl(allocator_arg_t, const _Alloc&, _Tuple_impl&&) { }
207 
208  protected:
209  void _M_swap(_Tuple_impl&) noexcept { /* no-op */ }
210  };
211 
212  template<typename _Tp>
213  struct __is_empty_non_tuple : is_empty<_Tp> { };
214 
215  // Using EBO for elements that are tuples causes ambiguous base errors.
216  template<typename _El0, typename... _El>
217  struct __is_empty_non_tuple<tuple<_El0, _El...>> : false_type { };
218 
219  // Use the Empty Base-class Optimization for empty, non-final types.
220  template<typename _Tp>
221  using __empty_not_final
222  = typename conditional<__is_final(_Tp), false_type,
223  __is_empty_non_tuple<_Tp>>::type;
224 
225  /**
226  * Recursive tuple implementation. Here we store the @c Head element
227  * and derive from a @c Tuple_impl containing the remaining elements
228  * (which contains the @c Tail).
229  */
230  template<std::size_t _Idx, typename _Head, typename... _Tail>
231  struct _Tuple_impl<_Idx, _Head, _Tail...>
232  : public _Tuple_impl<_Idx + 1, _Tail...>,
233  private _Head_base<_Idx, _Head, __empty_not_final<_Head>::value>
234  {
235  template<std::size_t, typename...> friend class _Tuple_impl;
236 
237  typedef _Tuple_impl<_Idx + 1, _Tail...> _Inherited;
238  typedef _Head_base<_Idx, _Head, __empty_not_final<_Head>::value> _Base;
239 
240  static constexpr _Head&
241  _M_head(_Tuple_impl& __t) noexcept { return _Base::_M_head(__t); }
242 
243  static constexpr const _Head&
244  _M_head(const _Tuple_impl& __t) noexcept { return _Base::_M_head(__t); }
245 
246  static constexpr _Inherited&
247  _M_tail(_Tuple_impl& __t) noexcept { return __t; }
248 
249  static constexpr const _Inherited&
250  _M_tail(const _Tuple_impl& __t) noexcept { return __t; }
251 
252  constexpr _Tuple_impl()
253  : _Inherited(), _Base() { }
254 
255  explicit
256  constexpr _Tuple_impl(const _Head& __head, const _Tail&... __tail)
257  : _Inherited(__tail...), _Base(__head) { }
258 
259  template<typename _UHead, typename... _UTail, typename = typename
260  enable_if<sizeof...(_Tail) == sizeof...(_UTail)>::type>
261  explicit
262  constexpr _Tuple_impl(_UHead&& __head, _UTail&&... __tail)
263  : _Inherited(std::forward<_UTail>(__tail)...),
264  _Base(std::forward<_UHead>(__head)) { }
265 
266  constexpr _Tuple_impl(const _Tuple_impl&) = default;
267 
268  constexpr
269  _Tuple_impl(_Tuple_impl&& __in)
270  noexcept(__and_<is_nothrow_move_constructible<_Head>,
271  is_nothrow_move_constructible<_Inherited>>::value)
272  : _Inherited(std::move(_M_tail(__in))),
273  _Base(std::forward<_Head>(_M_head(__in))) { }
274 
275  template<typename... _UElements>
276  constexpr _Tuple_impl(const _Tuple_impl<_Idx, _UElements...>& __in)
277  : _Inherited(_Tuple_impl<_Idx, _UElements...>::_M_tail(__in)),
278  _Base(_Tuple_impl<_Idx, _UElements...>::_M_head(__in)) { }
279 
280  template<typename _UHead, typename... _UTails>
281  constexpr _Tuple_impl(_Tuple_impl<_Idx, _UHead, _UTails...>&& __in)
282  : _Inherited(std::move
283  (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_tail(__in))),
284  _Base(std::forward<_UHead>
285  (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_head(__in))) { }
286 
287  template<typename _Alloc>
288  _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a)
289  : _Inherited(__tag, __a),
290  _Base(__tag, __use_alloc<_Head>(__a)) { }
291 
292  template<typename _Alloc>
293  _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
294  const _Head& __head, const _Tail&... __tail)
295  : _Inherited(__tag, __a, __tail...),
296  _Base(__use_alloc<_Head, _Alloc, _Head>(__a), __head) { }
297 
298  template<typename _Alloc, typename _UHead, typename... _UTail,
299  typename = typename enable_if<sizeof...(_Tail)
300  == sizeof...(_UTail)>::type>
301  _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
302  _UHead&& __head, _UTail&&... __tail)
303  : _Inherited(__tag, __a, std::forward<_UTail>(__tail)...),
304  _Base(__use_alloc<_Head, _Alloc, _UHead>(__a),
305  std::forward<_UHead>(__head)) { }
306 
307  template<typename _Alloc>
308  _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
309  const _Tuple_impl& __in)
310  : _Inherited(__tag, __a, _M_tail(__in)),
311  _Base(__use_alloc<_Head, _Alloc, _Head>(__a), _M_head(__in)) { }
312 
313  template<typename _Alloc>
314  _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
315  _Tuple_impl&& __in)
316  : _Inherited(__tag, __a, std::move(_M_tail(__in))),
317  _Base(__use_alloc<_Head, _Alloc, _Head>(__a),
318  std::forward<_Head>(_M_head(__in))) { }
319 
320  template<typename _Alloc, typename... _UElements>
321  _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
322  const _Tuple_impl<_Idx, _UElements...>& __in)
323  : _Inherited(__tag, __a,
324  _Tuple_impl<_Idx, _UElements...>::_M_tail(__in)),
325  _Base(__use_alloc<_Head, _Alloc, _Head>(__a),
326  _Tuple_impl<_Idx, _UElements...>::_M_head(__in)) { }
327 
328  template<typename _Alloc, typename _UHead, typename... _UTails>
329  _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
330  _Tuple_impl<_Idx, _UHead, _UTails...>&& __in)
331  : _Inherited(__tag, __a, std::move
332  (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_tail(__in))),
333  _Base(__use_alloc<_Head, _Alloc, _UHead>(__a),
334  std::forward<_UHead>
335  (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_head(__in))) { }
336 
337  _Tuple_impl&
338  operator=(const _Tuple_impl& __in)
339  {
340  _M_head(*this) = _M_head(__in);
341  _M_tail(*this) = _M_tail(__in);
342  return *this;
343  }
344 
345  _Tuple_impl&
346  operator=(_Tuple_impl&& __in)
347  noexcept(__and_<is_nothrow_move_assignable<_Head>,
348  is_nothrow_move_assignable<_Inherited>>::value)
349  {
350  _M_head(*this) = std::forward<_Head>(_M_head(__in));
351  _M_tail(*this) = std::move(_M_tail(__in));
352  return *this;
353  }
354 
355  template<typename... _UElements>
356  _Tuple_impl&
357  operator=(const _Tuple_impl<_Idx, _UElements...>& __in)
358  {
359  _M_head(*this) = _Tuple_impl<_Idx, _UElements...>::_M_head(__in);
360  _M_tail(*this) = _Tuple_impl<_Idx, _UElements...>::_M_tail(__in);
361  return *this;
362  }
363 
364  template<typename _UHead, typename... _UTails>
365  _Tuple_impl&
366  operator=(_Tuple_impl<_Idx, _UHead, _UTails...>&& __in)
367  {
368  _M_head(*this) = std::forward<_UHead>
369  (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_head(__in));
370  _M_tail(*this) = std::move
371  (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_tail(__in));
372  return *this;
373  }
374 
375  protected:
376  void
377  _M_swap(_Tuple_impl& __in)
378  noexcept(noexcept(swap(std::declval<_Head&>(),
379  std::declval<_Head&>()))
380  && noexcept(_M_tail(__in)._M_swap(_M_tail(__in))))
381  {
382  using std::swap;
383  swap(_M_head(*this), _M_head(__in));
384  _Inherited::_M_swap(_M_tail(__in));
385  }
386  };
387 
388  /// Primary class template, tuple
389  template<typename... _Elements>
390  class tuple : public _Tuple_impl<0, _Elements...>
391  {
392  typedef _Tuple_impl<0, _Elements...> _Inherited;
393 
394  public:
395  constexpr tuple()
396  : _Inherited() { }
397 
398  explicit
399  constexpr tuple(const _Elements&... __elements)
400  : _Inherited(__elements...) { }
401 
402  template<typename... _UElements, typename = typename
403  enable_if<__and_<is_convertible<_UElements,
404  _Elements>...>::value>::type>
405  explicit
406  constexpr tuple(_UElements&&... __elements)
407  : _Inherited(std::forward<_UElements>(__elements)...) { }
408 
409  constexpr tuple(const tuple&) = default;
410 
411  constexpr tuple(tuple&&) = default;
412 
413  template<typename... _UElements, typename = typename
414  enable_if<__and_<is_convertible<const _UElements&,
415  _Elements>...>::value>::type>
416  constexpr tuple(const tuple<_UElements...>& __in)
417  : _Inherited(static_cast<const _Tuple_impl<0, _UElements...>&>(__in))
418  { }
419 
420  template<typename... _UElements, typename = typename
421  enable_if<__and_<is_convertible<_UElements,
422  _Elements>...>::value>::type>
423  constexpr tuple(tuple<_UElements...>&& __in)
424  : _Inherited(static_cast<_Tuple_impl<0, _UElements...>&&>(__in)) { }
425 
426  // Allocator-extended constructors.
427 
428  template<typename _Alloc>
429  tuple(allocator_arg_t __tag, const _Alloc& __a)
430  : _Inherited(__tag, __a) { }
431 
432  template<typename _Alloc>
433  tuple(allocator_arg_t __tag, const _Alloc& __a,
434  const _Elements&... __elements)
435  : _Inherited(__tag, __a, __elements...) { }
436 
437  template<typename _Alloc, typename... _UElements, typename = typename
438  enable_if<sizeof...(_UElements)
439  == sizeof...(_Elements)>::type>
440  tuple(allocator_arg_t __tag, const _Alloc& __a,
441  _UElements&&... __elements)
442  : _Inherited(__tag, __a, std::forward<_UElements>(__elements)...)
443  { }
444 
445  template<typename _Alloc>
446  tuple(allocator_arg_t __tag, const _Alloc& __a, const tuple& __in)
447  : _Inherited(__tag, __a, static_cast<const _Inherited&>(__in)) { }
448 
449  template<typename _Alloc>
450  tuple(allocator_arg_t __tag, const _Alloc& __a, tuple&& __in)
451  : _Inherited(__tag, __a, static_cast<_Inherited&&>(__in)) { }
452 
453  template<typename _Alloc, typename... _UElements, typename = typename
454  enable_if<sizeof...(_UElements)
455  == sizeof...(_Elements)>::type>
456  tuple(allocator_arg_t __tag, const _Alloc& __a,
457  const tuple<_UElements...>& __in)
458  : _Inherited(__tag, __a,
459  static_cast<const _Tuple_impl<0, _UElements...>&>(__in))
460  { }
461 
462  template<typename _Alloc, typename... _UElements, typename = typename
463  enable_if<sizeof...(_UElements)
464  == sizeof...(_Elements)>::type>
465  tuple(allocator_arg_t __tag, const _Alloc& __a,
466  tuple<_UElements...>&& __in)
467  : _Inherited(__tag, __a,
468  static_cast<_Tuple_impl<0, _UElements...>&&>(__in))
469  { }
470 
471  tuple&
472  operator=(const tuple& __in)
473  {
474  static_cast<_Inherited&>(*this) = __in;
475  return *this;
476  }
477 
478  tuple&
479  operator=(tuple&& __in)
480  noexcept(is_nothrow_move_assignable<_Inherited>::value)
481  {
482  static_cast<_Inherited&>(*this) = std::move(__in);
483  return *this;
484  }
485 
486  template<typename... _UElements, typename = typename
487  enable_if<sizeof...(_UElements)
488  == sizeof...(_Elements)>::type>
489  tuple&
490  operator=(const tuple<_UElements...>& __in)
491  {
492  static_cast<_Inherited&>(*this) = __in;
493  return *this;
494  }
495 
496  template<typename... _UElements, typename = typename
497  enable_if<sizeof...(_UElements)
498  == sizeof...(_Elements)>::type>
499  tuple&
500  operator=(tuple<_UElements...>&& __in)
501  {
502  static_cast<_Inherited&>(*this) = std::move(__in);
503  return *this;
504  }
505 
506  void
507  swap(tuple& __in)
508  noexcept(noexcept(__in._M_swap(__in)))
509  { _Inherited::_M_swap(__in); }
510  };
511 
512  // Explicit specialization, zero-element tuple.
513  template<>
514  class tuple<>
515  {
516  public:
517  void swap(tuple&) noexcept { /* no-op */ }
518  };
519 
520  /// Partial specialization, 2-element tuple.
521  /// Includes construction and assignment from a pair.
522  template<typename _T1, typename _T2>
523  class tuple<_T1, _T2> : public _Tuple_impl<0, _T1, _T2>
524  {
525  typedef _Tuple_impl<0, _T1, _T2> _Inherited;
526 
527  public:
528  constexpr tuple()
529  : _Inherited() { }
530 
531  explicit
532  constexpr tuple(const _T1& __a1, const _T2& __a2)
533  : _Inherited(__a1, __a2) { }
534 
535  template<typename _U1, typename _U2, typename = typename
536  enable_if<__and_<is_convertible<_U1, _T1>,
537  is_convertible<_U2, _T2>>::value>::type>
538  explicit
539  constexpr tuple(_U1&& __a1, _U2&& __a2)
540  : _Inherited(std::forward<_U1>(__a1), std::forward<_U2>(__a2)) { }
541 
542  constexpr tuple(const tuple&) = default;
543 
544  constexpr tuple(tuple&&) = default;
545 
546  template<typename _U1, typename _U2, typename = typename
547  enable_if<__and_<is_convertible<const _U1&, _T1>,
548  is_convertible<const _U2&, _T2>>::value>::type>
549  constexpr tuple(const tuple<_U1, _U2>& __in)
550  : _Inherited(static_cast<const _Tuple_impl<0, _U1, _U2>&>(__in)) { }
551 
552  template<typename _U1, typename _U2, typename = typename
553  enable_if<__and_<is_convertible<_U1, _T1>,
554  is_convertible<_U2, _T2>>::value>::type>
555  constexpr tuple(tuple<_U1, _U2>&& __in)
556  : _Inherited(static_cast<_Tuple_impl<0, _U1, _U2>&&>(__in)) { }
557 
558  template<typename _U1, typename _U2, typename = typename
559  enable_if<__and_<is_convertible<const _U1&, _T1>,
560  is_convertible<const _U2&, _T2>>::value>::type>
561  constexpr tuple(const pair<_U1, _U2>& __in)
562  : _Inherited(__in.first, __in.second) { }
563 
564  template<typename _U1, typename _U2, typename = typename
565  enable_if<__and_<is_convertible<_U1, _T1>,
566  is_convertible<_U2, _T2>>::value>::type>
567  constexpr tuple(pair<_U1, _U2>&& __in)
568  : _Inherited(std::forward<_U1>(__in.first),
569  std::forward<_U2>(__in.second)) { }
570 
571  // Allocator-extended constructors.
572 
573  template<typename _Alloc>
574  tuple(allocator_arg_t __tag, const _Alloc& __a)
575  : _Inherited(__tag, __a) { }
576 
577  template<typename _Alloc>
578  tuple(allocator_arg_t __tag, const _Alloc& __a,
579  const _T1& __a1, const _T2& __a2)
580  : _Inherited(__tag, __a, __a1, __a2) { }
581 
582  template<typename _Alloc, typename _U1, typename _U2>
583  tuple(allocator_arg_t __tag, const _Alloc& __a, _U1&& __a1, _U2&& __a2)
584  : _Inherited(__tag, __a, std::forward<_U1>(__a1),
585  std::forward<_U2>(__a2)) { }
586 
587  template<typename _Alloc>
588  tuple(allocator_arg_t __tag, const _Alloc& __a, const tuple& __in)
589  : _Inherited(__tag, __a, static_cast<const _Inherited&>(__in)) { }
590 
591  template<typename _Alloc>
592  tuple(allocator_arg_t __tag, const _Alloc& __a, tuple&& __in)
593  : _Inherited(__tag, __a, static_cast<_Inherited&&>(__in)) { }
594 
595  template<typename _Alloc, typename _U1, typename _U2>
596  tuple(allocator_arg_t __tag, const _Alloc& __a,
597  const tuple<_U1, _U2>& __in)
598  : _Inherited(__tag, __a,
599  static_cast<const _Tuple_impl<0, _U1, _U2>&>(__in))
600  { }
601 
602  template<typename _Alloc, typename _U1, typename _U2>
603  tuple(allocator_arg_t __tag, const _Alloc& __a, tuple<_U1, _U2>&& __in)
604  : _Inherited(__tag, __a, static_cast<_Tuple_impl<0, _U1, _U2>&&>(__in))
605  { }
606 
607  template<typename _Alloc, typename _U1, typename _U2>
608  tuple(allocator_arg_t __tag, const _Alloc& __a,
609  const pair<_U1, _U2>& __in)
610  : _Inherited(__tag, __a, __in.first, __in.second) { }
611 
612  template<typename _Alloc, typename _U1, typename _U2>
613  tuple(allocator_arg_t __tag, const _Alloc& __a, pair<_U1, _U2>&& __in)
614  : _Inherited(__tag, __a, std::forward<_U1>(__in.first),
615  std::forward<_U2>(__in.second)) { }
616 
617  tuple&
618  operator=(const tuple& __in)
619  {
620  static_cast<_Inherited&>(*this) = __in;
621  return *this;
622  }
623 
624  tuple&
625  operator=(tuple&& __in)
626  noexcept(is_nothrow_move_assignable<_Inherited>::value)
627  {
628  static_cast<_Inherited&>(*this) = std::move(__in);
629  return *this;
630  }
631 
632  template<typename _U1, typename _U2>
633  tuple&
634  operator=(const tuple<_U1, _U2>& __in)
635  {
636  static_cast<_Inherited&>(*this) = __in;
637  return *this;
638  }
639 
640  template<typename _U1, typename _U2>
641  tuple&
642  operator=(tuple<_U1, _U2>&& __in)
643  {
644  static_cast<_Inherited&>(*this) = std::move(__in);
645  return *this;
646  }
647 
648  template<typename _U1, typename _U2>
649  tuple&
650  operator=(const pair<_U1, _U2>& __in)
651  {
652  this->_M_head(*this) = __in.first;
653  this->_M_tail(*this)._M_head(*this) = __in.second;
654  return *this;
655  }
656 
657  template<typename _U1, typename _U2>
658  tuple&
659  operator=(pair<_U1, _U2>&& __in)
660  {
661  this->_M_head(*this) = std::forward<_U1>(__in.first);
662  this->_M_tail(*this)._M_head(*this) = std::forward<_U2>(__in.second);
663  return *this;
664  }
665 
666  void
667  swap(tuple& __in)
668  noexcept(noexcept(__in._M_swap(__in)))
669  { _Inherited::_M_swap(__in); }
670  };
671 
672 
673  /// Gives the type of the ith element of a given tuple type.
674  template<std::size_t __i, typename _Tp>
675  struct tuple_element;
676 
677  /**
678  * Recursive case for tuple_element: strip off the first element in
679  * the tuple and retrieve the (i-1)th element of the remaining tuple.
680  */
681  template<std::size_t __i, typename _Head, typename... _Tail>
682  struct tuple_element<__i, tuple<_Head, _Tail...> >
683  : tuple_element<__i - 1, tuple<_Tail...> > { };
684 
685  /**
686  * Basis case for tuple_element: The first element is the one we're seeking.
687  */
688  template<typename _Head, typename... _Tail>
689  struct tuple_element<0, tuple<_Head, _Tail...> >
690  {
691  typedef _Head type;
692  };
693 
694  template<std::size_t __i, typename _Tp>
695  struct tuple_element<__i, const _Tp>
696  {
697  typedef typename
698  add_const<typename tuple_element<__i, _Tp>::type>::type type;
699  };
700 
701  template<std::size_t __i, typename _Tp>
702  struct tuple_element<__i, volatile _Tp>
703  {
704  typedef typename
705  add_volatile<typename tuple_element<__i, _Tp>::type>::type type;
706  };
707 
708  template<std::size_t __i, typename _Tp>
709  struct tuple_element<__i, const volatile _Tp>
710  {
711  typedef typename
712  add_cv<typename tuple_element<__i, _Tp>::type>::type type;
713  };
714 
715 #if __cplusplus > 201103L
716  template<std::size_t __i, typename _Tp>
717  using tuple_element_t = typename tuple_element<__i, _Tp>::type;
718 #endif
719 
720  /// Finds the size of a given tuple type.
721  template<typename _Tp>
722  struct tuple_size;
723 
724  // _GLIBCXX_RESOLVE_LIB_DEFECTS
725  // 2313. tuple_size should always derive from integral_constant<size_t, N>
726  template<typename _Tp>
727  struct tuple_size<const _Tp>
728  : public integral_constant<size_t, tuple_size<_Tp>::value> { };
729 
730  template<typename _Tp>
731  struct tuple_size<volatile _Tp>
732  : public integral_constant<size_t, tuple_size<_Tp>::value> { };
733 
734  template<typename _Tp>
735  struct tuple_size<const volatile _Tp>
736  : public integral_constant<size_t, tuple_size<_Tp>::value> { };
737 
738  /// class tuple_size
739  template<typename... _Elements>
740  struct tuple_size<tuple<_Elements...>>
741  : public integral_constant<std::size_t, sizeof...(_Elements)> { };
742 
743  template<std::size_t __i, typename _Head, typename... _Tail>
744  constexpr typename __add_ref<_Head>::type
745  __get_helper(_Tuple_impl<__i, _Head, _Tail...>& __t) noexcept
746  { return _Tuple_impl<__i, _Head, _Tail...>::_M_head(__t); }
747 
748  template<std::size_t __i, typename _Head, typename... _Tail>
749  constexpr typename __add_c_ref<_Head>::type
750  __get_helper(const _Tuple_impl<__i, _Head, _Tail...>& __t) noexcept
751  { return _Tuple_impl<__i, _Head, _Tail...>::_M_head(__t); }
752 
753  /// Return a reference to the ith element of a tuple.
754  template<std::size_t __i, typename... _Elements>
755  constexpr typename __add_ref<
756  typename tuple_element<__i, tuple<_Elements...>>::type
757  >::type
758  get(tuple<_Elements...>& __t) noexcept
759  { return std::__get_helper<__i>(__t); }
760 
761  /// Return a const reference to the ith element of a const tuple.
762  template<std::size_t __i, typename... _Elements>
763  constexpr typename __add_c_ref<
764  typename tuple_element<__i, tuple<_Elements...>>::type
765  >::type
766  get(const tuple<_Elements...>& __t) noexcept
767  { return std::__get_helper<__i>(__t); }
768 
769  /// Return an rvalue reference to the ith element of a tuple rvalue.
770  template<std::size_t __i, typename... _Elements>
771  constexpr typename __add_r_ref<
772  typename tuple_element<__i, tuple<_Elements...>>::type
773  >::type
774  get(tuple<_Elements...>&& __t) noexcept
775  { return std::forward<typename tuple_element<__i,
776  tuple<_Elements...>>::type&&>(get<__i>(__t)); }
777 
778 #if __cplusplus > 201103L
779 
780 #define __cpp_lib_tuples_by_type 201304
781 
782  template<typename _Head, size_t __i, typename... _Tail>
783  constexpr typename __add_ref<_Head>::type
784  __get_helper2(_Tuple_impl<__i, _Head, _Tail...>& __t) noexcept
785  { return _Tuple_impl<__i, _Head, _Tail...>::_M_head(__t); }
786 
787  template<typename _Head, size_t __i, typename... _Tail>
788  constexpr typename __add_c_ref<_Head>::type
789  __get_helper2(const _Tuple_impl<__i, _Head, _Tail...>& __t) noexcept
790  { return _Tuple_impl<__i, _Head, _Tail...>::_M_head(__t); }
791 
792  /// Return a reference to the unique element of type _Tp of a tuple.
793  template <typename _Tp, typename... _Types>
794  constexpr _Tp&
795  get(tuple<_Types...>& __t) noexcept
796  { return std::__get_helper2<_Tp>(__t); }
797 
798  /// Return a reference to the unique element of type _Tp of a tuple rvalue.
799  template <typename _Tp, typename... _Types>
800  constexpr _Tp&&
801  get(tuple<_Types...>&& __t) noexcept
802  { return std::forward<_Tp&&>(std::__get_helper2<_Tp>(__t)); }
803 
804  /// Return a const reference to the unique element of type _Tp of a tuple.
805  template <typename _Tp, typename... _Types>
806  constexpr const _Tp&
807  get(const tuple<_Types...>& __t) noexcept
808  { return std::__get_helper2<_Tp>(__t); }
809 #endif
810 
811 
812  // This class helps construct the various comparison operations on tuples
813  template<std::size_t __check_equal_size, std::size_t __i, std::size_t __j,
814  typename _Tp, typename _Up>
815  struct __tuple_compare;
816 
817  template<std::size_t __i, std::size_t __j, typename _Tp, typename _Up>
818  struct __tuple_compare<0, __i, __j, _Tp, _Up>
819  {
820  static constexpr bool
821  __eq(const _Tp& __t, const _Up& __u)
822  {
823  return (get<__i>(__t) == get<__i>(__u) &&
824  __tuple_compare<0, __i + 1, __j, _Tp, _Up>::__eq(__t, __u));
825  }
826 
827  static constexpr bool
828  __less(const _Tp& __t, const _Up& __u)
829  {
830  return ((get<__i>(__t) < get<__i>(__u))
831  || !(get<__i>(__u) < get<__i>(__t)) &&
832  __tuple_compare<0, __i + 1, __j, _Tp, _Up>::__less(__t, __u));
833  }
834  };
835 
836  template<std::size_t __i, typename _Tp, typename _Up>
837  struct __tuple_compare<0, __i, __i, _Tp, _Up>
838  {
839  static constexpr bool
840  __eq(const _Tp&, const _Up&) { return true; }
841 
842  static constexpr bool
843  __less(const _Tp&, const _Up&) { return false; }
844  };
845 
846  template<typename... _TElements, typename... _UElements>
847  constexpr bool
848  operator==(const tuple<_TElements...>& __t,
849  const tuple<_UElements...>& __u)
850  {
851  typedef tuple<_TElements...> _Tp;
852  typedef tuple<_UElements...> _Up;
853  return bool(__tuple_compare<tuple_size<_Tp>::value - tuple_size<_Up>::value,
854  0, tuple_size<_Tp>::value, _Tp, _Up>::__eq(__t, __u));
855  }
856 
857  template<typename... _TElements, typename... _UElements>
858  constexpr bool
859  operator<(const tuple<_TElements...>& __t,
860  const tuple<_UElements...>& __u)
861  {
862  typedef tuple<_TElements...> _Tp;
863  typedef tuple<_UElements...> _Up;
864  return bool(__tuple_compare<tuple_size<_Tp>::value - tuple_size<_Up>::value,
865  0, tuple_size<_Tp>::value, _Tp, _Up>::__less(__t, __u));
866  }
867 
868  template<typename... _TElements, typename... _UElements>
869  constexpr bool
870  operator!=(const tuple<_TElements...>& __t,
871  const tuple<_UElements...>& __u)
872  { return !(__t == __u); }
873 
874  template<typename... _TElements, typename... _UElements>
875  constexpr bool
876  operator>(const tuple<_TElements...>& __t,
877  const tuple<_UElements...>& __u)
878  { return __u < __t; }
879 
880  template<typename... _TElements, typename... _UElements>
881  constexpr bool
882  operator<=(const tuple<_TElements...>& __t,
883  const tuple<_UElements...>& __u)
884  { return !(__u < __t); }
885 
886  template<typename... _TElements, typename... _UElements>
887  constexpr bool
888  operator>=(const tuple<_TElements...>& __t,
889  const tuple<_UElements...>& __u)
890  { return !(__t < __u); }
891 
892  // NB: DR 705.
893  template<typename... _Elements>
894  constexpr tuple<typename __decay_and_strip<_Elements>::__type...>
895  make_tuple(_Elements&&... __args)
896  {
897  typedef tuple<typename __decay_and_strip<_Elements>::__type...>
898  __result_type;
899  return __result_type(std::forward<_Elements>(__args)...);
900  }
901 
902  template<typename... _Elements>
903  tuple<_Elements&&...>
904  forward_as_tuple(_Elements&&... __args) noexcept
905  { return tuple<_Elements&&...>(std::forward<_Elements>(__args)...); }
906 
907  template<typename>
908  struct __is_tuple_like_impl : false_type
909  { };
910 
911  template<typename... _Tps>
912  struct __is_tuple_like_impl<tuple<_Tps...>> : true_type
913  { };
914 
915  template<typename _T1, typename _T2>
916  struct __is_tuple_like_impl<pair<_T1, _T2>> : true_type
917  { };
918 
919  template<typename _Tp, std::size_t _Nm>
920  struct __is_tuple_like_impl<array<_Tp, _Nm>> : true_type
921  { };
922 
923  // Internal type trait that allows us to sfinae-protect tuple_cat.
924  template<typename _Tp>
925  struct __is_tuple_like
926  : public __is_tuple_like_impl<typename std::remove_cv
927  <typename std::remove_reference<_Tp>::type>::type>::type
928  { };
929 
930  template<std::size_t, typename, typename, std::size_t>
931  struct __make_tuple_impl;
932 
933  template<std::size_t _Idx, typename _Tuple, typename... _Tp,
934  std::size_t _Nm>
935  struct __make_tuple_impl<_Idx, tuple<_Tp...>, _Tuple, _Nm>
936  {
937  typedef typename __make_tuple_impl<_Idx + 1, tuple<_Tp...,
938  typename std::tuple_element<_Idx, _Tuple>::type>, _Tuple, _Nm>::__type
939  __type;
940  };
941 
942  template<std::size_t _Nm, typename _Tuple, typename... _Tp>
943  struct __make_tuple_impl<_Nm, tuple<_Tp...>, _Tuple, _Nm>
944  {
945  typedef tuple<_Tp...> __type;
946  };
947 
948  template<typename _Tuple>
949  struct __do_make_tuple
950  : public __make_tuple_impl<0, tuple<>, _Tuple,
951  std::tuple_size<_Tuple>::value>
952  { };
953 
954  // Returns the std::tuple equivalent of a tuple-like type.
955  template<typename _Tuple>
956  struct __make_tuple
957  : public __do_make_tuple<typename std::remove_cv
958  <typename std::remove_reference<_Tuple>::type>::type>
959  { };
960 
961  // Combines several std::tuple's into a single one.
962  template<typename...>
963  struct __combine_tuples;
964 
965  template<>
966  struct __combine_tuples<>
967  {
968  typedef tuple<> __type;
969  };
970 
971  template<typename... _Ts>
972  struct __combine_tuples<tuple<_Ts...>>
973  {
974  typedef tuple<_Ts...> __type;
975  };
976 
977  template<typename... _T1s, typename... _T2s, typename... _Rem>
978  struct __combine_tuples<tuple<_T1s...>, tuple<_T2s...>, _Rem...>
979  {
980  typedef typename __combine_tuples<tuple<_T1s..., _T2s...>,
981  _Rem...>::__type __type;
982  };
983 
984  // Computes the result type of tuple_cat given a set of tuple-like types.
985  template<typename... _Tpls>
986  struct __tuple_cat_result
987  {
988  typedef typename __combine_tuples
989  <typename __make_tuple<_Tpls>::__type...>::__type __type;
990  };
991 
992  // Helper to determine the index set for the first tuple-like
993  // type of a given set.
994  template<typename...>
995  struct __make_1st_indices;
996 
997  template<>
998  struct __make_1st_indices<>
999  {
1000  typedef std::_Index_tuple<> __type;
1001  };
1002 
1003  template<typename _Tp, typename... _Tpls>
1004  struct __make_1st_indices<_Tp, _Tpls...>
1005  {
1006  typedef typename std::_Build_index_tuple<std::tuple_size<
1007  typename std::remove_reference<_Tp>::type>::value>::__type __type;
1008  };
1009 
1010  // Performs the actual concatenation by step-wise expanding tuple-like
1011  // objects into the elements, which are finally forwarded into the
1012  // result tuple.
1013  template<typename _Ret, typename _Indices, typename... _Tpls>
1014  struct __tuple_concater;
1015 
1016  template<typename _Ret, std::size_t... _Is, typename _Tp, typename... _Tpls>
1017  struct __tuple_concater<_Ret, std::_Index_tuple<_Is...>, _Tp, _Tpls...>
1018  {
1019  template<typename... _Us>
1020  static constexpr _Ret
1021  _S_do(_Tp&& __tp, _Tpls&&... __tps, _Us&&... __us)
1022  {
1023  typedef typename __make_1st_indices<_Tpls...>::__type __idx;
1024  typedef __tuple_concater<_Ret, __idx, _Tpls...> __next;
1025  return __next::_S_do(std::forward<_Tpls>(__tps)...,
1026  std::forward<_Us>(__us)...,
1027  std::get<_Is>(std::forward<_Tp>(__tp))...);
1028  }
1029  };
1030 
1031  template<typename _Ret>
1032  struct __tuple_concater<_Ret, std::_Index_tuple<>>
1033  {
1034  template<typename... _Us>
1035  static constexpr _Ret
1036  _S_do(_Us&&... __us)
1037  {
1038  return _Ret(std::forward<_Us>(__us)...);
1039  }
1040  };
1041 
1042  /// tuple_cat
1043  template<typename... _Tpls, typename = typename
1044  enable_if<__and_<__is_tuple_like<_Tpls>...>::value>::type>
1045  constexpr auto
1046  tuple_cat(_Tpls&&... __tpls)
1047  -> typename __tuple_cat_result<_Tpls...>::__type
1048  {
1049  typedef typename __tuple_cat_result<_Tpls...>::__type __ret;
1050  typedef typename __make_1st_indices<_Tpls...>::__type __idx;
1051  typedef __tuple_concater<__ret, __idx, _Tpls...> __concater;
1052  return __concater::_S_do(std::forward<_Tpls>(__tpls)...);
1053  }
1054 
1055  /// tie
1056  template<typename... _Elements>
1057  inline tuple<_Elements&...>
1058  tie(_Elements&... __args) noexcept
1059  { return tuple<_Elements&...>(__args...); }
1060 
1061  /// swap
1062  template<typename... _Elements>
1063  inline void
1064  swap(tuple<_Elements...>& __x, tuple<_Elements...>& __y)
1065  noexcept(noexcept(__x.swap(__y)))
1066  { __x.swap(__y); }
1067 
1068  // A class (and instance) which can be used in 'tie' when an element
1069  // of a tuple is not required
1070  struct _Swallow_assign
1071  {
1072  template<class _Tp>
1073  const _Swallow_assign&
1074  operator=(const _Tp&) const
1075  { return *this; }
1076  };
1077 
1078  const _Swallow_assign ignore{};
1079 
1080  /// Partial specialization for tuples
1081  template<typename... _Types, typename _Alloc>
1082  struct uses_allocator<tuple<_Types...>, _Alloc> : true_type { };
1083 
1084  // See stl_pair.h...
1085  template<class _T1, class _T2>
1086  template<typename... _Args1, typename... _Args2>
1087  inline
1088  pair<_T1, _T2>::
1089  pair(piecewise_construct_t,
1090  tuple<_Args1...> __first, tuple<_Args2...> __second)
1091  : pair(__first, __second,
1092  typename _Build_index_tuple<sizeof...(_Args1)>::__type(),
1093  typename _Build_index_tuple<sizeof...(_Args2)>::__type())
1094  { }
1095 
1096  template<class _T1, class _T2>
1097  template<typename... _Args1, std::size_t... _Indexes1,
1098  typename... _Args2, std::size_t... _Indexes2>
1099  inline
1100  pair<_T1, _T2>::
1101  pair(tuple<_Args1...>& __tuple1, tuple<_Args2...>& __tuple2,
1102  _Index_tuple<_Indexes1...>, _Index_tuple<_Indexes2...>)
1103  : first(std::forward<_Args1>(std::get<_Indexes1>(__tuple1))...),
1104  second(std::forward<_Args2>(std::get<_Indexes2>(__tuple2))...)
1105  { }
1106 
1107  /// @}
1108 
1109 _GLIBCXX_END_NAMESPACE_VERSION
1110 } // namespace std
1111 
1112 #endif // C++11
1113 
1114 #endif // _GLIBCXX_TUPLE