libstdc++
tuple
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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  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)) { }
96 
97  _Head_base(__uses_alloc0)
98  : _Head() { }
99 
100  template<typename _Alloc>
101  _Head_base(__uses_alloc1<_Alloc> __a)
102  : _Head(allocator_arg, *__a._M_a) { }
103 
104  template<typename _Alloc>
105  _Head_base(__uses_alloc2<_Alloc> __a)
106  : _Head(*__a._M_a) { }
107 
108  template<typename _UHead>
109  _Head_base(__uses_alloc0, _UHead&& __uhead)
110  : _Head(std::forward<_UHead>(__uhead)) { }
111 
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)) { }
115 
116  template<typename _Alloc, typename _UHead>
117  _Head_base(__uses_alloc2<_Alloc> __a, _UHead&& __uhead)
118  : _Head(std::forward<_UHead>(__uhead), *__a._M_a) { }
119 
120  static constexpr _Head&
121  _M_head(_Head_base& __b) noexcept { return __b; }
122 
123  static constexpr const _Head&
124  _M_head(const _Head_base& __b) noexcept { return __b; }
125  };
126 
127  template<std::size_t _Idx, typename _Head>
128  struct _Head_base<_Idx, _Head, false>
129  {
130  constexpr _Head_base()
131  : _M_head_impl() { }
132 
133  constexpr _Head_base(const _Head& __h)
134  : _M_head_impl(__h) { }
135 
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)) { }
141 
142  _Head_base(__uses_alloc0)
143  : _M_head_impl() { }
144 
145  template<typename _Alloc>
146  _Head_base(__uses_alloc1<_Alloc> __a)
147  : _M_head_impl(allocator_arg, *__a._M_a) { }
148 
149  template<typename _Alloc>
150  _Head_base(__uses_alloc2<_Alloc> __a)
151  : _M_head_impl(*__a._M_a) { }
152 
153  template<typename _UHead>
154  _Head_base(__uses_alloc0, _UHead&& __uhead)
155  : _M_head_impl(std::forward<_UHead>(__uhead)) { }
156 
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))
160  { }
161 
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) { }
165 
166  static constexpr _Head&
167  _M_head(_Head_base& __b) noexcept { return __b._M_head_impl; }
168 
169  static constexpr const _Head&
170  _M_head(const _Head_base& __b) noexcept { return __b._M_head_impl; }
171 
172  _Head _M_head_impl;
173  };
174 
175  /**
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
181  * get() operation.
182  */
183  template<std::size_t _Idx, typename... _Elements>
184  struct _Tuple_impl;
185 
186  /**
187  * Zero-element tuple implementation. This is the basis case for the
188  * inheritance recursion.
189  */
190  template<std::size_t _Idx>
191  struct _Tuple_impl<_Idx>
192  {
193  template<std::size_t, typename...> friend class _Tuple_impl;
194 
195  _Tuple_impl() = default;
196 
197  template<typename _Alloc>
198  _Tuple_impl(allocator_arg_t, const _Alloc&) { }
199 
200  template<typename _Alloc>
201  _Tuple_impl(allocator_arg_t, const _Alloc&, const _Tuple_impl&) { }
202 
203  template<typename _Alloc>
204  _Tuple_impl(allocator_arg_t, const _Alloc&, _Tuple_impl&&) { }
205 
206  protected:
207  void _M_swap(_Tuple_impl&) noexcept { /* no-op */ }
208  };
209 
210  template<typename _Tp>
211  struct __is_empty_non_tuple : is_empty<_Tp> { };
212 
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 { };
216 
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;
222 
223  /**
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).
227  */
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>
232  {
233  template<std::size_t, typename...> friend class _Tuple_impl;
234 
235  typedef _Tuple_impl<_Idx + 1, _Tail...> _Inherited;
236  typedef _Head_base<_Idx, _Head, __empty_not_final<_Head>::value> _Base;
237 
238  static constexpr _Head&
239  _M_head(_Tuple_impl& __t) noexcept { return _Base::_M_head(__t); }
240 
241  static constexpr const _Head&
242  _M_head(const _Tuple_impl& __t) noexcept { return _Base::_M_head(__t); }
243 
244  static constexpr _Inherited&
245  _M_tail(_Tuple_impl& __t) noexcept { return __t; }
246 
247  static constexpr const _Inherited&
248  _M_tail(const _Tuple_impl& __t) noexcept { return __t; }
249 
250  constexpr _Tuple_impl()
251  : _Inherited(), _Base() { }
252 
253  explicit
254  constexpr _Tuple_impl(const _Head& __head, const _Tail&... __tail)
255  : _Inherited(__tail...), _Base(__head) { }
256 
257  template<typename _UHead, typename... _UTail, typename = typename
258  enable_if<sizeof...(_Tail) == sizeof...(_UTail)>::type>
259  explicit
260  constexpr _Tuple_impl(_UHead&& __head, _UTail&&... __tail)
261  : _Inherited(std::forward<_UTail>(__tail)...),
262  _Base(std::forward<_UHead>(__head)) { }
263 
264  constexpr _Tuple_impl(const _Tuple_impl&) = default;
265 
266  constexpr
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))) { }
272 
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)) { }
277 
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))) { }
284 
285  template<typename _Alloc>
286  _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a)
287  : _Inherited(__tag, __a),
288  _Base(__use_alloc<_Head>(__a)) { }
289 
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) { }
295 
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)) { }
304 
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)) { }
310 
311  template<typename _Alloc>
312  _Tuple_impl(allocator_arg_t __tag, const _Alloc& __a,
313  _Tuple_impl&& __in)
314  : _Inherited(__tag, __a, std::move(_M_tail(__in))),
315  _Base(__use_alloc<_Head, _Alloc, _Head>(__a),
316  std::forward<_Head>(_M_head(__in))) { }
317 
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)) { }
325 
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),
332  std::forward<_UHead>
333  (_Tuple_impl<_Idx, _UHead, _UTails...>::_M_head(__in))) { }
334 
335  _Tuple_impl&
336  operator=(const _Tuple_impl& __in)
337  {
338  _M_head(*this) = _M_head(__in);
339  _M_tail(*this) = _M_tail(__in);
340  return *this;
341  }
342 
343  _Tuple_impl&
344  operator=(_Tuple_impl&& __in)
345  noexcept(__and_<is_nothrow_move_assignable<_Head>,
346  is_nothrow_move_assignable<_Inherited>>::value)
347  {
348  _M_head(*this) = std::forward<_Head>(_M_head(__in));
349  _M_tail(*this) = std::move(_M_tail(__in));
350  return *this;
351  }
352 
353  template<typename... _UElements>
354  _Tuple_impl&
355  operator=(const _Tuple_impl<_Idx, _UElements...>& __in)
356  {
357  _M_head(*this) = _Tuple_impl<_Idx, _UElements...>::_M_head(__in);
358  _M_tail(*this) = _Tuple_impl<_Idx, _UElements...>::_M_tail(__in);
359  return *this;
360  }
361 
362  template<typename _UHead, typename... _UTails>
363  _Tuple_impl&
364  operator=(_Tuple_impl<_Idx, _UHead, _UTails...>&& __in)
365  {
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));
370  return *this;
371  }
372 
373  protected:
374  void
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))))
379  {
380  using std::swap;
381  swap(_M_head(*this), _M_head(__in));
382  _Inherited::_M_swap(_M_tail(__in));
383  }
384  };
385 
386  /// Primary class template, tuple
387  template<typename... _Elements>
388  class tuple : public _Tuple_impl<0, _Elements...>
389  {
390  typedef _Tuple_impl<0, _Elements...> _Inherited;
391 
392  public:
393  constexpr tuple()
394  : _Inherited() { }
395 
396  explicit
397  constexpr tuple(const _Elements&... __elements)
398  : _Inherited(__elements...) { }
399 
400  template<typename... _UElements, typename = typename
401  enable_if<__and_<is_convertible<_UElements,
402  _Elements>...>::value>::type>
403  explicit
404  constexpr tuple(_UElements&&... __elements)
405  : _Inherited(std::forward<_UElements>(__elements)...) { }
406 
407  constexpr tuple(const tuple&) = default;
408 
409  constexpr tuple(tuple&&) = default;
410 
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))
416  { }
417 
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)) { }
423 
424  // Allocator-extended constructors.
425 
426  template<typename _Alloc>
427  tuple(allocator_arg_t __tag, const _Alloc& __a)
428  : _Inherited(__tag, __a) { }
429 
430  template<typename _Alloc>
431  tuple(allocator_arg_t __tag, const _Alloc& __a,
432  const _Elements&... __elements)
433  : _Inherited(__tag, __a, __elements...) { }
434 
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)...)
441  { }
442 
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)) { }
446 
447  template<typename _Alloc>
448  tuple(allocator_arg_t __tag, const _Alloc& __a, tuple&& __in)
449  : _Inherited(__tag, __a, static_cast<_Inherited&&>(__in)) { }
450 
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))
458  { }
459 
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))
467  { }
468 
469  tuple&
470  operator=(const tuple& __in)
471  {
472  static_cast<_Inherited&>(*this) = __in;
473  return *this;
474  }
475 
476  tuple&
477  operator=(tuple&& __in)
478  noexcept(is_nothrow_move_assignable<_Inherited>::value)
479  {
480  static_cast<_Inherited&>(*this) = std::move(__in);
481  return *this;
482  }
483 
484  template<typename... _UElements, typename = typename
485  enable_if<sizeof...(_UElements)
486  == sizeof...(_Elements)>::type>
487  tuple&
488  operator=(const tuple<_UElements...>& __in)
489  {
490  static_cast<_Inherited&>(*this) = __in;
491  return *this;
492  }
493 
494  template<typename... _UElements, typename = typename
495  enable_if<sizeof...(_UElements)
496  == sizeof...(_Elements)>::type>
497  tuple&
498  operator=(tuple<_UElements...>&& __in)
499  {
500  static_cast<_Inherited&>(*this) = std::move(__in);
501  return *this;
502  }
503 
504  void
505  swap(tuple& __in)
506  noexcept(noexcept(__in._M_swap(__in)))
507  { _Inherited::_M_swap(__in); }
508  };
509 
510  // Explicit specialization, zero-element tuple.
511  template<>
512  class tuple<>
513  {
514  public:
515  void swap(tuple&) noexcept { /* no-op */ }
516  };
517 
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>
522  {
523  typedef _Tuple_impl<0, _T1, _T2> _Inherited;
524 
525  public:
526  constexpr tuple()
527  : _Inherited() { }
528 
529  explicit
530  constexpr tuple(const _T1& __a1, const _T2& __a2)
531  : _Inherited(__a1, __a2) { }
532 
533  template<typename _U1, typename _U2, typename = typename
534  enable_if<__and_<is_convertible<_U1, _T1>,
535  is_convertible<_U2, _T2>>::value>::type>
536  explicit
537  constexpr tuple(_U1&& __a1, _U2&& __a2)
538  : _Inherited(std::forward<_U1>(__a1), std::forward<_U2>(__a2)) { }
539 
540  constexpr tuple(const tuple&) = default;
541 
542  constexpr tuple(tuple&&) = default;
543 
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)) { }
549 
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)) { }
555 
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) { }
561 
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)) { }
568 
569  // Allocator-extended constructors.
570 
571  template<typename _Alloc>
572  tuple(allocator_arg_t __tag, const _Alloc& __a)
573  : _Inherited(__tag, __a) { }
574 
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) { }
579 
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)) { }
584 
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)) { }
588 
589  template<typename _Alloc>
590  tuple(allocator_arg_t __tag, const _Alloc& __a, tuple&& __in)
591  : _Inherited(__tag, __a, static_cast<_Inherited&&>(__in)) { }
592 
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))
598  { }
599 
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))
603  { }
604 
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) { }
609 
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)) { }
614 
615  tuple&
616  operator=(const tuple& __in)
617  {
618  static_cast<_Inherited&>(*this) = __in;
619  return *this;
620  }
621 
622  tuple&
623  operator=(tuple&& __in)
624  noexcept(is_nothrow_move_assignable<_Inherited>::value)
625  {
626  static_cast<_Inherited&>(*this) = std::move(__in);
627  return *this;
628  }
629 
630  template<typename _U1, typename _U2>
631  tuple&
632  operator=(const tuple<_U1, _U2>& __in)
633  {
634  static_cast<_Inherited&>(*this) = __in;
635  return *this;
636  }
637 
638  template<typename _U1, typename _U2>
639  tuple&
640  operator=(tuple<_U1, _U2>&& __in)
641  {
642  static_cast<_Inherited&>(*this) = std::move(__in);
643  return *this;
644  }
645 
646  template<typename _U1, typename _U2>
647  tuple&
648  operator=(const pair<_U1, _U2>& __in)
649  {
650  this->_M_head(*this) = __in.first;
651  this->_M_tail(*this)._M_head(*this) = __in.second;
652  return *this;
653  }
654 
655  template<typename _U1, typename _U2>
656  tuple&
657  operator=(pair<_U1, _U2>&& __in)
658  {
659  this->_M_head(*this) = std::forward<_U1>(__in.first);
660  this->_M_tail(*this)._M_head(*this) = std::forward<_U2>(__in.second);
661  return *this;
662  }
663 
664  void
665  swap(tuple& __in)
666  noexcept(noexcept(__in._M_swap(__in)))
667  { _Inherited::_M_swap(__in); }
668  };
669 
670 
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;
674 
675  /**
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.
678  */
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...> > { };
682 
683  /**
684  * Basis case for tuple_element: The first element is the one we're seeking.
685  */
686  template<typename _Head, typename... _Tail>
687  struct tuple_element<0, tuple<_Head, _Tail...> >
688  {
689  typedef _Head type;
690  };
691 
692  template<std::size_t __i, typename _Tp>
693  struct tuple_element<__i, const _Tp>
694  {
695  typedef typename
696  add_const<typename tuple_element<__i, _Tp>::type>::type type;
697  };
698 
699  template<std::size_t __i, typename _Tp>
700  struct tuple_element<__i, volatile _Tp>
701  {
702  typedef typename
703  add_volatile<typename tuple_element<__i, _Tp>::type>::type type;
704  };
705 
706  template<std::size_t __i, typename _Tp>
707  struct tuple_element<__i, const volatile _Tp>
708  {
709  typedef typename
710  add_cv<typename tuple_element<__i, _Tp>::type>::type type;
711  };
712 
713  /// Finds the size of a given tuple type.
714  template<typename _Tp>
715  struct tuple_size;
716 
717  template<typename _Tp>
718  struct tuple_size<const _Tp>
719  : public integral_constant<
720  typename remove_cv<decltype(tuple_size<_Tp>::value)>::type,
721  tuple_size<_Tp>::value> { };
722 
723  template<typename _Tp>
724  struct tuple_size<volatile _Tp>
725  : public integral_constant<
726  typename remove_cv<decltype(tuple_size<_Tp>::value)>::type,
727  tuple_size<_Tp>::value> { };
728 
729  template<typename _Tp>
730  struct tuple_size<const volatile _Tp>
731  : public integral_constant<
732  typename remove_cv<decltype(tuple_size<_Tp>::value)>::type,
733  tuple_size<_Tp>::value> { };
734 
735  /// class tuple_size
736  template<typename... _Elements>
737  struct tuple_size<tuple<_Elements...>>
738  : public integral_constant<std::size_t, sizeof...(_Elements)> { };
739 
740  template<std::size_t __i, typename _Head, typename... _Tail>
741  constexpr typename __add_ref<_Head>::type
742  __get_helper(_Tuple_impl<__i, _Head, _Tail...>& __t) noexcept
743  { return _Tuple_impl<__i, _Head, _Tail...>::_M_head(__t); }
744 
745  template<std::size_t __i, typename _Head, typename... _Tail>
746  constexpr typename __add_c_ref<_Head>::type
747  __get_helper(const _Tuple_impl<__i, _Head, _Tail...>& __t) noexcept
748  { return _Tuple_impl<__i, _Head, _Tail...>::_M_head(__t); }
749 
750  // Return a reference (const reference, rvalue reference) to the ith element
751  // of a tuple. Any const or non-const ref elements are returned with their
752  // original type.
753  template<std::size_t __i, typename... _Elements>
754  constexpr typename __add_ref<
755  typename tuple_element<__i, tuple<_Elements...>>::type
756  >::type
757  get(tuple<_Elements...>& __t) noexcept
758  { return __get_helper<__i>(__t); }
759 
760  template<std::size_t __i, typename... _Elements>
761  constexpr typename __add_c_ref<
762  typename tuple_element<__i, tuple<_Elements...>>::type
763  >::type
764  get(const tuple<_Elements...>& __t) noexcept
765  { return __get_helper<__i>(__t); }
766 
767  template<std::size_t __i, typename... _Elements>
768  constexpr typename __add_r_ref<
769  typename tuple_element<__i, tuple<_Elements...>>::type
770  >::type
771  get(tuple<_Elements...>&& __t) noexcept
772  { return std::forward<typename tuple_element<__i,
773  tuple<_Elements...>>::type&&>(get<__i>(__t)); }
774 
775 #if __cplusplus > 201103L
776  template<typename _Head, size_t __i, typename... _Tail>
777  constexpr typename __add_ref<_Head>::type
778  __get_helper2(_Tuple_impl<__i, _Head, _Tail...>& __t) noexcept
779  { return _Tuple_impl<__i, _Head, _Tail...>::_M_head(__t); }
780 
781  template<typename _Head, size_t __i, typename... _Tail>
782  constexpr typename __add_c_ref<_Head>::type
783  __get_helper2(const _Tuple_impl<__i, _Head, _Tail...>& __t) noexcept
784  { return _Tuple_impl<__i, _Head, _Tail...>::_M_head(__t); }
785 
786  template <typename _Tp, typename... _Types>
787  constexpr _Tp&
788  get(tuple<_Types...>& __t) noexcept
789  { return __get_helper2<_Tp>(__t); }
790 
791  template <typename _Tp, typename... _Types>
792  constexpr _Tp&&
793  get(tuple<_Types...>&& __t) noexcept
794  { return std::move(__get_helper2<_Tp>(__t)); }
795 
796  template <typename _Tp, typename... _Types>
797  constexpr const _Tp&
798  get(const tuple<_Types...>& __t) noexcept
799  { return __get_helper2<_Tp>(__t); }
800 #endif
801 
802  // This class helps construct the various comparison operations on tuples
803  template<std::size_t __check_equal_size, std::size_t __i, std::size_t __j,
804  typename _Tp, typename _Up>
805  struct __tuple_compare;
806 
807  template<std::size_t __i, std::size_t __j, typename _Tp, typename _Up>
808  struct __tuple_compare<0, __i, __j, _Tp, _Up>
809  {
810  static constexpr bool
811  __eq(const _Tp& __t, const _Up& __u)
812  {
813  return (get<__i>(__t) == get<__i>(__u) &&
814  __tuple_compare<0, __i + 1, __j, _Tp, _Up>::__eq(__t, __u));
815  }
816 
817  static constexpr bool
818  __less(const _Tp& __t, const _Up& __u)
819  {
820  return ((get<__i>(__t) < get<__i>(__u))
821  || !(get<__i>(__u) < get<__i>(__t)) &&
822  __tuple_compare<0, __i + 1, __j, _Tp, _Up>::__less(__t, __u));
823  }
824  };
825 
826  template<std::size_t __i, typename _Tp, typename _Up>
827  struct __tuple_compare<0, __i, __i, _Tp, _Up>
828  {
829  static constexpr bool
830  __eq(const _Tp&, const _Up&) { return true; }
831 
832  static constexpr bool
833  __less(const _Tp&, const _Up&) { return false; }
834  };
835 
836  template<typename... _TElements, typename... _UElements>
837  constexpr bool
838  operator==(const tuple<_TElements...>& __t,
839  const tuple<_UElements...>& __u)
840  {
841  typedef tuple<_TElements...> _Tp;
842  typedef tuple<_UElements...> _Up;
843  return bool(__tuple_compare<tuple_size<_Tp>::value - tuple_size<_Up>::value,
844  0, tuple_size<_Tp>::value, _Tp, _Up>::__eq(__t, __u));
845  }
846 
847  template<typename... _TElements, typename... _UElements>
848  constexpr bool
849  operator<(const tuple<_TElements...>& __t,
850  const tuple<_UElements...>& __u)
851  {
852  typedef tuple<_TElements...> _Tp;
853  typedef tuple<_UElements...> _Up;
854  return bool(__tuple_compare<tuple_size<_Tp>::value - tuple_size<_Up>::value,
855  0, tuple_size<_Tp>::value, _Tp, _Up>::__less(__t, __u));
856  }
857 
858  template<typename... _TElements, typename... _UElements>
859  constexpr bool
860  operator!=(const tuple<_TElements...>& __t,
861  const tuple<_UElements...>& __u)
862  { return !(__t == __u); }
863 
864  template<typename... _TElements, typename... _UElements>
865  constexpr bool
866  operator>(const tuple<_TElements...>& __t,
867  const tuple<_UElements...>& __u)
868  { return __u < __t; }
869 
870  template<typename... _TElements, typename... _UElements>
871  constexpr bool
872  operator<=(const tuple<_TElements...>& __t,
873  const tuple<_UElements...>& __u)
874  { return !(__u < __t); }
875 
876  template<typename... _TElements, typename... _UElements>
877  constexpr bool
878  operator>=(const tuple<_TElements...>& __t,
879  const tuple<_UElements...>& __u)
880  { return !(__t < __u); }
881 
882  // NB: DR 705.
883  template<typename... _Elements>
884  constexpr tuple<typename __decay_and_strip<_Elements>::__type...>
885  make_tuple(_Elements&&... __args)
886  {
887  typedef tuple<typename __decay_and_strip<_Elements>::__type...>
888  __result_type;
889  return __result_type(std::forward<_Elements>(__args)...);
890  }
891 
892  template<typename... _Elements>
893  tuple<_Elements&&...>
894  forward_as_tuple(_Elements&&... __args) noexcept
895  { return tuple<_Elements&&...>(std::forward<_Elements>(__args)...); }
896 
897  template<typename>
898  struct __is_tuple_like_impl : false_type
899  { };
900 
901  template<typename... _Tps>
902  struct __is_tuple_like_impl<tuple<_Tps...>> : true_type
903  { };
904 
905  template<typename _T1, typename _T2>
906  struct __is_tuple_like_impl<pair<_T1, _T2>> : true_type
907  { };
908 
909  template<typename _Tp, std::size_t _Nm>
910  struct __is_tuple_like_impl<array<_Tp, _Nm>> : true_type
911  { };
912 
913  // Internal type trait that allows us to sfinae-protect tuple_cat.
914  template<typename _Tp>
915  struct __is_tuple_like
916  : public __is_tuple_like_impl<typename std::remove_cv
917  <typename std::remove_reference<_Tp>::type>::type>::type
918  { };
919 
920  template<std::size_t, typename, typename, std::size_t>
921  struct __make_tuple_impl;
922 
923  template<std::size_t _Idx, typename _Tuple, typename... _Tp,
924  std::size_t _Nm>
925  struct __make_tuple_impl<_Idx, tuple<_Tp...>, _Tuple, _Nm>
926  {
927  typedef typename __make_tuple_impl<_Idx + 1, tuple<_Tp...,
928  typename std::tuple_element<_Idx, _Tuple>::type>, _Tuple, _Nm>::__type
929  __type;
930  };
931 
932  template<std::size_t _Nm, typename _Tuple, typename... _Tp>
933  struct __make_tuple_impl<_Nm, tuple<_Tp...>, _Tuple, _Nm>
934  {
935  typedef tuple<_Tp...> __type;
936  };
937 
938  template<typename _Tuple>
939  struct __do_make_tuple
940  : public __make_tuple_impl<0, tuple<>, _Tuple,
941  std::tuple_size<_Tuple>::value>
942  { };
943 
944  // Returns the std::tuple equivalent of a tuple-like type.
945  template<typename _Tuple>
946  struct __make_tuple
947  : public __do_make_tuple<typename std::remove_cv
948  <typename std::remove_reference<_Tuple>::type>::type>
949  { };
950 
951  // Combines several std::tuple's into a single one.
952  template<typename...>
953  struct __combine_tuples;
954 
955  template<>
956  struct __combine_tuples<>
957  {
958  typedef tuple<> __type;
959  };
960 
961  template<typename... _Ts>
962  struct __combine_tuples<tuple<_Ts...>>
963  {
964  typedef tuple<_Ts...> __type;
965  };
966 
967  template<typename... _T1s, typename... _T2s, typename... _Rem>
968  struct __combine_tuples<tuple<_T1s...>, tuple<_T2s...>, _Rem...>
969  {
970  typedef typename __combine_tuples<tuple<_T1s..., _T2s...>,
971  _Rem...>::__type __type;
972  };
973 
974  // Computes the result type of tuple_cat given a set of tuple-like types.
975  template<typename... _Tpls>
976  struct __tuple_cat_result
977  {
978  typedef typename __combine_tuples
979  <typename __make_tuple<_Tpls>::__type...>::__type __type;
980  };
981 
982  // Helper to determine the index set for the first tuple-like
983  // type of a given set.
984  template<typename...>
985  struct __make_1st_indices;
986 
987  template<>
988  struct __make_1st_indices<>
989  {
990  typedef std::_Index_tuple<> __type;
991  };
992 
993  template<typename _Tp, typename... _Tpls>
994  struct __make_1st_indices<_Tp, _Tpls...>
995  {
996  typedef typename std::_Build_index_tuple<std::tuple_size<
997  typename std::remove_reference<_Tp>::type>::value>::__type __type;
998  };
999 
1000  // Performs the actual concatenation by step-wise expanding tuple-like
1001  // objects into the elements, which are finally forwarded into the
1002  // result tuple.
1003  template<typename _Ret, typename _Indices, typename... _Tpls>
1004  struct __tuple_concater;
1005 
1006  template<typename _Ret, std::size_t... _Is, typename _Tp, typename... _Tpls>
1007  struct __tuple_concater<_Ret, std::_Index_tuple<_Is...>, _Tp, _Tpls...>
1008  {
1009  template<typename... _Us>
1010  static constexpr _Ret
1011  _S_do(_Tp&& __tp, _Tpls&&... __tps, _Us&&... __us)
1012  {
1013  typedef typename __make_1st_indices<_Tpls...>::__type __idx;
1014  typedef __tuple_concater<_Ret, __idx, _Tpls...> __next;
1015  return __next::_S_do(std::forward<_Tpls>(__tps)...,
1016  std::forward<_Us>(__us)...,
1017  std::get<_Is>(std::forward<_Tp>(__tp))...);
1018  }
1019  };
1020 
1021  template<typename _Ret>
1022  struct __tuple_concater<_Ret, std::_Index_tuple<>>
1023  {
1024  template<typename... _Us>
1025  static constexpr _Ret
1026  _S_do(_Us&&... __us)
1027  {
1028  return _Ret(std::forward<_Us>(__us)...);
1029  }
1030  };
1031 
1032  /// tuple_cat
1033  template<typename... _Tpls, typename = typename
1034  enable_if<__and_<__is_tuple_like<_Tpls>...>::value>::type>
1035  constexpr auto
1036  tuple_cat(_Tpls&&... __tpls)
1037  -> typename __tuple_cat_result<_Tpls...>::__type
1038  {
1039  typedef typename __tuple_cat_result<_Tpls...>::__type __ret;
1040  typedef typename __make_1st_indices<_Tpls...>::__type __idx;
1041  typedef __tuple_concater<__ret, __idx, _Tpls...> __concater;
1042  return __concater::_S_do(std::forward<_Tpls>(__tpls)...);
1043  }
1044 
1045  /// tie
1046  template<typename... _Elements>
1047  inline tuple<_Elements&...>
1048  tie(_Elements&... __args) noexcept
1049  { return tuple<_Elements&...>(__args...); }
1050 
1051  /// swap
1052  template<typename... _Elements>
1053  inline void
1054  swap(tuple<_Elements...>& __x, tuple<_Elements...>& __y)
1055  noexcept(noexcept(__x.swap(__y)))
1056  { __x.swap(__y); }
1057 
1058  // A class (and instance) which can be used in 'tie' when an element
1059  // of a tuple is not required
1060  struct _Swallow_assign
1061  {
1062  template<class _Tp>
1063  const _Swallow_assign&
1064  operator=(const _Tp&) const
1065  { return *this; }
1066  };
1067 
1068  const _Swallow_assign ignore{};
1069 
1070  /// Partial specialization for tuples
1071  template<typename... _Types, typename _Alloc>
1072  struct uses_allocator<tuple<_Types...>, _Alloc> : true_type { };
1073 
1074  // See stl_pair.h...
1075  template<class _T1, class _T2>
1076  template<typename... _Args1, typename... _Args2>
1077  inline
1078  pair<_T1, _T2>::
1079  pair(piecewise_construct_t,
1080  tuple<_Args1...> __first, tuple<_Args2...> __second)
1081  : pair(__first, __second,
1082  typename _Build_index_tuple<sizeof...(_Args1)>::__type(),
1083  typename _Build_index_tuple<sizeof...(_Args2)>::__type())
1084  { }
1085 
1086  template<class _T1, class _T2>
1087  template<typename... _Args1, std::size_t... _Indexes1,
1088  typename... _Args2, std::size_t... _Indexes2>
1089  inline
1090  pair<_T1, _T2>::
1091  pair(tuple<_Args1...>& __tuple1, tuple<_Args2...>& __tuple2,
1092  _Index_tuple<_Indexes1...>, _Index_tuple<_Indexes2...>)
1093  : first(std::forward<_Args1>(std::get<_Indexes1>(__tuple1))...),
1094  second(std::forward<_Args2>(std::get<_Indexes2>(__tuple2))...)
1095  { }
1096 
1097  /// @}
1098 
1099 _GLIBCXX_END_NAMESPACE_VERSION
1100 } // namespace std
1101 
1102 #endif // C++11
1103 
1104 #endif // _GLIBCXX_TUPLE
std::tuple
Primary class template, tuple.
Definition: tuple:388
std::pair::second
_T2 second
first is a copy of the first object
Definition: stl_pair.h:102
std::tuple_size
tuple_size
Definition: array:307
std::__tuple_cat_result::__type
__combine_tuples< typename __make_tuple< _Tpls >::__type...>::__type __type
tuple_cat
Definition: tuple:979
std::pair::first
_T1 first
second_type is the second bound type
Definition: stl_pair.h:101
std::uses_allocator
Declare uses_allocator so it can be specialized in &lt;queue&gt; etc.
Definition: memoryfwd.h:71
std::pair::pair
constexpr pair()
second is a copy of the second object
Definition: stl_pair.h:108
std::pair
Struct holding two objects of arbitrary type.
Definition: stl_pair.h:96
std::tuple_element
tuple_element
Definition: array:315
std::piecewise_construct_t
piecewise_construct_t
Definition: stl_pair.h:76
std::allocator_arg_t
[allocator.tag]
Definition: uses_allocator.h:39
std::integral_constant
integral_constant
Definition: type_traits:57
std::is_empty
is_empty
Definition: type_traits:615
std::forward
constexpr _Tp && forward(typename std::remove_reference< _Tp >::type &__t) noexcept
Forward an lvalue.
Definition: move.h:76
std::true_type
integral_constant< bool, true > true_type
The type used as a compile-time boolean with true value.
Definition: type_traits:72
std::tie
tuple< _Elements &...> tie(_Elements &...__args) noexcept
tie
Definition: tuple:1048
std::swap
void swap(function< _Res(_Args...)> &__x, function< _Res(_Args...)> &__y)
Swap the targets of two polymorphic function object wrappers.
Definition: functional:2534
std::false_type
integral_constant< bool, false > false_type
The type used as a compile-time boolean with false value.
Definition: type_traits:75