libstdc++
tuple
Go to the documentation of this file.
1 // <tuple> -*- C++ -*-
2 
3 // Copyright (C) 2007, 2008, 2009, 2010, 2011 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 #ifndef __GXX_EXPERIMENTAL_CXX0X__
35 # include <bits/c++0x_warning.h>
36 #else
37 
38 #include <utility>
39 
40 namespace std _GLIBCXX_VISIBILITY(default)
41 {
42 _GLIBCXX_BEGIN_NAMESPACE_VERSION
43 
44  // Adds a const reference to a non-reference type.
45  template<typename _Tp>
46  struct __add_c_ref
47  { typedef const _Tp& type; };
48 
49  template<typename _Tp>
50  struct __add_c_ref<_Tp&>
51  { typedef _Tp& type; };
52 
53  // Adds a reference to a non-reference type.
54  template<typename _Tp>
55  struct __add_ref
56  { typedef _Tp& type; };
57 
58  template<typename _Tp>
59  struct __add_ref<_Tp&>
60  { typedef _Tp& type; };
61 
62  template<std::size_t _Idx, typename _Head, bool _IsEmpty>
63  struct _Head_base;
64 
65  template<std::size_t _Idx, typename _Head>
66  struct _Head_base<_Idx, _Head, true>
67  : public _Head
68  {
69  constexpr _Head_base()
70  : _Head() { }
71 
72  constexpr _Head_base(const _Head& __h)
73  : _Head(__h) { }
74 
75  template<typename _UHead>
76  _Head_base(_UHead&& __h)
77  : _Head(std::forward<_UHead>(__h)) { }
78 
79  _Head& _M_head() { return *this; }
80  const _Head& _M_head() const { return *this; }
81 
82  void
83  _M_swap_impl(_Head& __h)
84  {
85  using std::swap;
86  swap(__h, _M_head());
87  }
88  };
89 
90  template<std::size_t _Idx, typename _Head>
91  struct _Head_base<_Idx, _Head, false>
92  {
93  constexpr _Head_base()
94  : _M_head_impl() { }
95 
96  constexpr _Head_base(const _Head& __h)
97  : _M_head_impl(__h) { }
98 
99  template<typename _UHead>
100  _Head_base(_UHead&& __h)
101  : _M_head_impl(std::forward<_UHead>(__h)) { }
102 
103  _Head& _M_head() { return _M_head_impl; }
104  const _Head& _M_head() const { return _M_head_impl; }
105 
106  void
107  _M_swap_impl(_Head& __h)
108  {
109  using std::swap;
110  swap(__h, _M_head());
111  }
112 
113  _Head _M_head_impl;
114  };
115 
116  /**
117  * Contains the actual implementation of the @c tuple template, stored
118  * as a recursive inheritance hierarchy from the first element (most
119  * derived class) to the last (least derived class). The @c Idx
120  * parameter gives the 0-based index of the element stored at this
121  * point in the hierarchy; we use it to implement a constant-time
122  * get() operation.
123  */
124  template<std::size_t _Idx, typename... _Elements>
125  struct _Tuple_impl;
126 
127  /**
128  * Zero-element tuple implementation. This is the basis case for the
129  * inheritance recursion.
130  */
131  template<std::size_t _Idx>
132  struct _Tuple_impl<_Idx>
133  {
134  protected:
135  void _M_swap_impl(_Tuple_impl&) { /* no-op */ }
136  };
137 
138  /**
139  * Recursive tuple implementation. Here we store the @c Head element
140  * and derive from a @c Tuple_impl containing the remaining elements
141  * (which contains the @c Tail).
142  */
143  template<std::size_t _Idx, typename _Head, typename... _Tail>
144  struct _Tuple_impl<_Idx, _Head, _Tail...>
145  : public _Tuple_impl<_Idx + 1, _Tail...>,
146  private _Head_base<_Idx, _Head, std::is_empty<_Head>::value>
147  {
148  typedef _Tuple_impl<_Idx + 1, _Tail...> _Inherited;
149  typedef _Head_base<_Idx, _Head, std::is_empty<_Head>::value> _Base;
150 
151  _Head& _M_head() { return _Base::_M_head(); }
152  const _Head& _M_head() const { return _Base::_M_head(); }
153 
154  _Inherited& _M_tail() { return *this; }
155  const _Inherited& _M_tail() const { return *this; }
156 
157  constexpr _Tuple_impl()
158  : _Inherited(), _Base() { }
159 
160  explicit
161  constexpr _Tuple_impl(const _Head& __head, const _Tail&... __tail)
162  : _Inherited(__tail...), _Base(__head) { }
163 
164  template<typename _UHead, typename... _UTail>
165  explicit
166  _Tuple_impl(_UHead&& __head, _UTail&&... __tail)
167  : _Inherited(std::forward<_UTail>(__tail)...),
168  _Base(std::forward<_UHead>(__head)) { }
169 
170  constexpr _Tuple_impl(const _Tuple_impl&) = default;
171 
172  _Tuple_impl(_Tuple_impl&& __in)
173  : _Inherited(std::move(__in._M_tail())),
174  _Base(std::forward<_Head>(__in._M_head())) { }
175 
176  template<typename... _UElements>
177  _Tuple_impl(const _Tuple_impl<_Idx, _UElements...>& __in)
178  : _Inherited(__in._M_tail()), _Base(__in._M_head()) { }
179 
180  template<typename _UHead, typename... _UTails>
181  _Tuple_impl(_Tuple_impl<_Idx, _UHead, _UTails...>&& __in)
182  : _Inherited(std::move(__in._M_tail())),
183  _Base(std::forward<_UHead>(__in._M_head())) { }
184 
185  _Tuple_impl&
186  operator=(const _Tuple_impl& __in)
187  {
188  _M_head() = __in._M_head();
189  _M_tail() = __in._M_tail();
190  return *this;
191  }
192 
193  _Tuple_impl&
194  operator=(_Tuple_impl&& __in)
195  {
196  _M_head() = std::forward<_Head>(__in._M_head());
197  _M_tail() = std::move(__in._M_tail());
198  return *this;
199  }
200 
201  template<typename... _UElements>
202  _Tuple_impl&
203  operator=(const _Tuple_impl<_Idx, _UElements...>& __in)
204  {
205  _M_head() = __in._M_head();
206  _M_tail() = __in._M_tail();
207  return *this;
208  }
209 
210  template<typename _UHead, typename... _UTails>
211  _Tuple_impl&
212  operator=(_Tuple_impl<_Idx, _UHead, _UTails...>&& __in)
213  {
214  _M_head() = std::forward<_UHead>(__in._M_head());
215  _M_tail() = std::move(__in._M_tail());
216  return *this;
217  }
218 
219  protected:
220  void
221  _M_swap_impl(_Tuple_impl& __in)
222  {
223  _Base::_M_swap_impl(__in._M_head());
224  _Inherited::_M_swap_impl(__in._M_tail());
225  }
226  };
227 
228  /// tuple
229  template<typename... _Elements>
230  class tuple : public _Tuple_impl<0, _Elements...>
231  {
232  typedef _Tuple_impl<0, _Elements...> _Inherited;
233 
234  public:
235  constexpr tuple()
236  : _Inherited() { }
237 
238  explicit
239  constexpr tuple(const _Elements&... __elements)
240  : _Inherited(__elements...) { }
241 
242  template<typename... _UElements, typename = typename
243  std::enable_if<sizeof...(_UElements)
244  == sizeof...(_Elements)>::type>
245  explicit
246  tuple(_UElements&&... __elements)
247  : _Inherited(std::forward<_UElements>(__elements)...) { }
248 
249  constexpr tuple(const tuple&) = default;
250 
251  tuple(tuple&& __in)
252  : _Inherited(static_cast<_Inherited&&>(__in)) { }
253 
254  template<typename... _UElements, typename = typename
255  std::enable_if<sizeof...(_UElements)
256  == sizeof...(_Elements)>::type>
257  tuple(const tuple<_UElements...>& __in)
258  : _Inherited(static_cast<const _Tuple_impl<0, _UElements...>&>(__in))
259  { }
260 
261  template<typename... _UElements, typename = typename
262  std::enable_if<sizeof...(_UElements)
263  == sizeof...(_Elements)>::type>
264  tuple(tuple<_UElements...>&& __in)
265  : _Inherited(static_cast<_Tuple_impl<0, _UElements...>&&>(__in)) { }
266 
267  tuple&
268  operator=(const tuple& __in)
269  {
270  static_cast<_Inherited&>(*this) = __in;
271  return *this;
272  }
273 
274  tuple&
275  operator=(tuple&& __in)
276  {
277  static_cast<_Inherited&>(*this) = std::move(__in);
278  return *this;
279  }
280 
281  template<typename... _UElements, typename = typename
282  std::enable_if<sizeof...(_UElements)
283  == sizeof...(_Elements)>::type>
284  tuple&
285  operator=(const tuple<_UElements...>& __in)
286  {
287  static_cast<_Inherited&>(*this) = __in;
288  return *this;
289  }
290 
291  template<typename... _UElements, typename = typename
292  std::enable_if<sizeof...(_UElements)
293  == sizeof...(_Elements)>::type>
294  tuple&
295  operator=(tuple<_UElements...>&& __in)
296  {
297  static_cast<_Inherited&>(*this) = std::move(__in);
298  return *this;
299  }
300 
301  void
302  swap(tuple& __in)
303  { _Inherited::_M_swap_impl(__in); }
304  };
305 
306  template<>
307  class tuple<>
308  {
309  public:
310  void swap(tuple&) { /* no-op */ }
311  };
312 
313  /// tuple (2-element), with construction and assignment from a pair.
314  template<typename _T1, typename _T2>
315  class tuple<_T1, _T2> : public _Tuple_impl<0, _T1, _T2>
316  {
318 
319  public:
320  constexpr tuple()
321  : _Inherited() { }
322 
323  explicit
324  constexpr tuple(const _T1& __a1, const _T2& __a2)
325  : _Inherited(__a1, __a2) { }
326 
327  template<typename _U1, typename _U2>
328  explicit
329  tuple(_U1&& __a1, _U2&& __a2)
330  : _Inherited(std::forward<_U1>(__a1), std::forward<_U2>(__a2)) { }
331 
332  constexpr tuple(const tuple&) = default;
333 
334  tuple(tuple&& __in)
335  : _Inherited(static_cast<_Inherited&&>(__in)) { }
336 
337  template<typename _U1, typename _U2>
338  tuple(const tuple<_U1, _U2>& __in)
339  : _Inherited(static_cast<const _Tuple_impl<0, _U1, _U2>&>(__in)) { }
340 
341  template<typename _U1, typename _U2>
342  tuple(tuple<_U1, _U2>&& __in)
343  : _Inherited(static_cast<_Tuple_impl<0, _U1, _U2>&&>(__in)) { }
344 
345  template<typename _U1, typename _U2>
346  tuple(const pair<_U1, _U2>& __in)
347  : _Inherited(__in.first, __in.second) { }
348 
349  template<typename _U1, typename _U2>
350  tuple(pair<_U1, _U2>&& __in)
351  : _Inherited(std::forward<_U1>(__in.first),
352  std::forward<_U2>(__in.second)) { }
353 
354  tuple&
355  operator=(const tuple& __in)
356  {
357  static_cast<_Inherited&>(*this) = __in;
358  return *this;
359  }
360 
361  tuple&
362  operator=(tuple&& __in)
363  {
364  static_cast<_Inherited&>(*this) = std::move(__in);
365  return *this;
366  }
367 
368  template<typename _U1, typename _U2>
369  tuple&
370  operator=(const tuple<_U1, _U2>& __in)
371  {
372  static_cast<_Inherited&>(*this) = __in;
373  return *this;
374  }
375 
376  template<typename _U1, typename _U2>
377  tuple&
378  operator=(tuple<_U1, _U2>&& __in)
379  {
380  static_cast<_Inherited&>(*this) = std::move(__in);
381  return *this;
382  }
383 
384  template<typename _U1, typename _U2>
385  tuple&
386  operator=(const pair<_U1, _U2>& __in)
387  {
388  this->_M_head() = __in.first;
389  this->_M_tail()._M_head() = __in.second;
390  return *this;
391  }
392 
393  template<typename _U1, typename _U2>
394  tuple&
395  operator=(pair<_U1, _U2>&& __in)
396  {
397  this->_M_head() = std::forward<_U1>(__in.first);
398  this->_M_tail()._M_head() = std::forward<_U2>(__in.second);
399  return *this;
400  }
401 
402  void
403  swap(tuple& __in)
404  {
405  using std::swap;
406  swap(this->_M_head(), __in._M_head());
407  swap(this->_M_tail()._M_head(), __in._M_tail()._M_head());
408  }
409  };
410 
411  /// tuple (1-element).
412  template<typename _T1>
413  class tuple<_T1> : public _Tuple_impl<0, _T1>
414  {
416 
417  public:
418  constexpr tuple()
419  : _Inherited() { }
420 
421  explicit
422  constexpr tuple(const _T1& __a1)
423  : _Inherited(__a1) { }
424 
425  template<typename _U1, typename = typename
427  explicit
428  tuple(_U1&& __a1)
429  : _Inherited(std::forward<_U1>(__a1)) { }
430 
431  constexpr tuple(const tuple&) = default;
432 
433  tuple(tuple&& __in)
434  : _Inherited(static_cast<_Inherited&&>(__in)) { }
435 
436  template<typename _U1>
437  tuple(const tuple<_U1>& __in)
438  : _Inherited(static_cast<const _Tuple_impl<0, _U1>&>(__in)) { }
439 
440  template<typename _U1>
441  tuple(tuple<_U1>&& __in)
442  : _Inherited(static_cast<_Tuple_impl<0, _U1>&&>(__in)) { }
443 
444  tuple&
445  operator=(const tuple& __in)
446  {
447  static_cast<_Inherited&>(*this) = __in;
448  return *this;
449  }
450 
451  tuple&
452  operator=(tuple&& __in)
453  {
454  static_cast<_Inherited&>(*this) = std::move(__in);
455  return *this;
456  }
457 
458  template<typename _U1>
459  tuple&
460  operator=(const tuple<_U1>& __in)
461  {
462  static_cast<_Inherited&>(*this) = __in;
463  return *this;
464  }
465 
466  template<typename _U1>
467  tuple&
468  operator=(tuple<_U1>&& __in)
469  {
470  static_cast<_Inherited&>(*this) = std::move(__in);
471  return *this;
472  }
473 
474  void
475  swap(tuple& __in)
476  { _Inherited::_M_swap_impl(__in); }
477  };
478 
479 
480  /// Gives the type of the ith element of a given tuple type.
481  template<std::size_t __i, typename _Tp>
482  struct tuple_element;
483 
484  /**
485  * Recursive case for tuple_element: strip off the first element in
486  * the tuple and retrieve the (i-1)th element of the remaining tuple.
487  */
488  template<std::size_t __i, typename _Head, typename... _Tail>
489  struct tuple_element<__i, tuple<_Head, _Tail...> >
490  : tuple_element<__i - 1, tuple<_Tail...> > { };
491 
492  /**
493  * Basis case for tuple_element: The first element is the one we're seeking.
494  */
495  template<typename _Head, typename... _Tail>
496  struct tuple_element<0, tuple<_Head, _Tail...> >
497  {
498  typedef _Head type;
499  };
500 
501  /// Finds the size of a given tuple type.
502  template<typename _Tp>
503  struct tuple_size;
504 
505  /// class tuple_size
506  template<typename... _Elements>
507  struct tuple_size<tuple<_Elements...> >
508  {
509  static const std::size_t value = sizeof...(_Elements);
510  };
511 
512  template<typename... _Elements>
513  const std::size_t tuple_size<tuple<_Elements...> >::value;
514 
515  template<std::size_t __i, typename _Head, typename... _Tail>
516  inline typename __add_ref<_Head>::type
517  __get_helper(_Tuple_impl<__i, _Head, _Tail...>& __t)
518  { return __t._M_head(); }
519 
520  template<std::size_t __i, typename _Head, typename... _Tail>
521  inline typename __add_c_ref<_Head>::type
522  __get_helper(const _Tuple_impl<__i, _Head, _Tail...>& __t)
523  { return __t._M_head(); }
524 
525  // Return a reference (const reference) to the ith element of a tuple.
526  // Any const or non-const ref elements are returned with their original type.
527  template<std::size_t __i, typename... _Elements>
528  inline typename __add_ref<
529  typename tuple_element<__i, tuple<_Elements...> >::type
530  >::type
531  get(tuple<_Elements...>& __t)
532  { return __get_helper<__i>(__t); }
533 
534  template<std::size_t __i, typename... _Elements>
535  inline typename __add_c_ref<
536  typename tuple_element<__i, tuple<_Elements...> >::type
537  >::type
538  get(const tuple<_Elements...>& __t)
539  { return __get_helper<__i>(__t); }
540 
541  // This class helps construct the various comparison operations on tuples
542  template<std::size_t __check_equal_size, std::size_t __i, std::size_t __j,
543  typename _Tp, typename _Up>
544  struct __tuple_compare;
545 
546  template<std::size_t __i, std::size_t __j, typename _Tp, typename _Up>
547  struct __tuple_compare<0, __i, __j, _Tp, _Up>
548  {
549  static bool __eq(const _Tp& __t, const _Up& __u)
550  {
551  return (get<__i>(__t) == get<__i>(__u) &&
552  __tuple_compare<0, __i + 1, __j, _Tp, _Up>::__eq(__t, __u));
553  }
554 
555  static bool __less(const _Tp& __t, const _Up& __u)
556  {
557  return ((get<__i>(__t) < get<__i>(__u))
558  || !(get<__i>(__u) < get<__i>(__t)) &&
559  __tuple_compare<0, __i + 1, __j, _Tp, _Up>::__less(__t, __u));
560  }
561  };
562 
563  template<std::size_t __i, typename _Tp, typename _Up>
564  struct __tuple_compare<0, __i, __i, _Tp, _Up>
565  {
566  static bool __eq(const _Tp&, const _Up&)
567  { return true; }
568 
569  static bool __less(const _Tp&, const _Up&)
570  { return false; }
571  };
572 
573  template<typename... _TElements, typename... _UElements>
574  bool
575  operator==(const tuple<_TElements...>& __t,
576  const tuple<_UElements...>& __u)
577  {
578  typedef tuple<_TElements...> _Tp;
579  typedef tuple<_UElements...> _Up;
580  return (__tuple_compare<tuple_size<_Tp>::value - tuple_size<_Up>::value,
581  0, tuple_size<_Tp>::value, _Tp, _Up>::__eq(__t, __u));
582  }
583 
584  template<typename... _TElements, typename... _UElements>
585  bool
586  operator<(const tuple<_TElements...>& __t,
587  const tuple<_UElements...>& __u)
588  {
589  typedef tuple<_TElements...> _Tp;
590  typedef tuple<_UElements...> _Up;
591  return (__tuple_compare<tuple_size<_Tp>::value - tuple_size<_Up>::value,
592  0, tuple_size<_Tp>::value, _Tp, _Up>::__less(__t, __u));
593  }
594 
595  template<typename... _TElements, typename... _UElements>
596  inline bool
597  operator!=(const tuple<_TElements...>& __t,
598  const tuple<_UElements...>& __u)
599  { return !(__t == __u); }
600 
601  template<typename... _TElements, typename... _UElements>
602  inline bool
603  operator>(const tuple<_TElements...>& __t,
604  const tuple<_UElements...>& __u)
605  { return __u < __t; }
606 
607  template<typename... _TElements, typename... _UElements>
608  inline bool
609  operator<=(const tuple<_TElements...>& __t,
610  const tuple<_UElements...>& __u)
611  { return !(__u < __t); }
612 
613  template<typename... _TElements, typename... _UElements>
614  inline bool
615  operator>=(const tuple<_TElements...>& __t,
616  const tuple<_UElements...>& __u)
617  { return !(__t < __u); }
618 
619  // NB: DR 705.
620  template<typename... _Elements>
621  inline tuple<typename __decay_and_strip<_Elements>::__type...>
622  make_tuple(_Elements&&... __args)
623  {
624  typedef tuple<typename __decay_and_strip<_Elements>::__type...>
625  __result_type;
626  return __result_type(std::forward<_Elements>(__args)...);
627  }
628 
629  template<typename... _Elements>
630  inline tuple<_Elements&&...>
631  forward_as_tuple(_Elements&&... __args)
632  { return tuple<_Elements&&...>(std::forward<_Elements>(__args)...); }
633 
634  template<std::size_t...> struct __index_holder { };
635 
636  template<std::size_t __i, typename _IdxHolder, typename... _Elements>
637  struct __index_holder_impl;
638 
639  template<std::size_t __i, std::size_t... _Indexes, typename _IdxHolder,
640  typename... _Elements>
641  struct __index_holder_impl<__i, __index_holder<_Indexes...>,
642  _IdxHolder, _Elements...>
643  {
644  typedef typename __index_holder_impl<__i + 1,
645  __index_holder<_Indexes..., __i>,
646  _Elements...>::type type;
647  };
648 
649  template<std::size_t __i, std::size_t... _Indexes>
650  struct __index_holder_impl<__i, __index_holder<_Indexes...> >
651  { typedef __index_holder<_Indexes...> type; };
652 
653  template<typename... _Elements>
654  struct __make_index_holder
655  : __index_holder_impl<0, __index_holder<>, _Elements...> { };
656 
657  template<typename... _TElements, std::size_t... _TIdx,
658  typename... _UElements, std::size_t... _UIdx>
659  inline tuple<_TElements..., _UElements...>
660  __tuple_cat_helper(const tuple<_TElements...>& __t,
661  const __index_holder<_TIdx...>&,
662  const tuple<_UElements...>& __u,
663  const __index_holder<_UIdx...>&)
664  { return tuple<_TElements..., _UElements...>(get<_TIdx>(__t)...,
665  get<_UIdx>(__u)...); }
666 
667  template<typename... _TElements, std::size_t... _TIdx,
668  typename... _UElements, std::size_t... _UIdx>
669  inline tuple<_TElements..., _UElements...>
670  __tuple_cat_helper(tuple<_TElements...>&& __t,
671  const __index_holder<_TIdx...>&,
672  const tuple<_UElements...>& __u,
673  const __index_holder<_UIdx...>&)
674  { return tuple<_TElements..., _UElements...>
675  (std::forward<_TElements>(get<_TIdx>(__t))..., get<_UIdx>(__u)...); }
676 
677  template<typename... _TElements, std::size_t... _TIdx,
678  typename... _UElements, std::size_t... _UIdx>
679  inline tuple<_TElements..., _UElements...>
680  __tuple_cat_helper(const tuple<_TElements...>& __t,
681  const __index_holder<_TIdx...>&,
682  tuple<_UElements...>&& __u,
683  const __index_holder<_UIdx...>&)
684  { return tuple<_TElements..., _UElements...>
685  (get<_TIdx>(__t)..., std::forward<_UElements>(get<_UIdx>(__u))...); }
686 
687  template<typename... _TElements, std::size_t... _TIdx,
688  typename... _UElements, std::size_t... _UIdx>
689  inline tuple<_TElements..., _UElements...>
690  __tuple_cat_helper(tuple<_TElements...>&& __t,
691  const __index_holder<_TIdx...>&,
692  tuple<_UElements...>&& __u,
693  const __index_holder<_UIdx...>&)
694  { return tuple<_TElements..., _UElements...>
695  (std::forward<_TElements>(get<_TIdx>(__t))...,
696  std::forward<_UElements>(get<_UIdx>(__u))...); }
697 
698  template<typename... _TElements, typename... _UElements>
699  inline tuple<_TElements..., _UElements...>
700  tuple_cat(const tuple<_TElements...>& __t, const tuple<_UElements...>& __u)
701  {
702  return __tuple_cat_helper(__t, typename
703  __make_index_holder<_TElements...>::type(),
704  __u, typename
705  __make_index_holder<_UElements...>::type());
706  }
707 
708  template<typename... _TElements, typename... _UElements>
709  inline tuple<_TElements..., _UElements...>
710  tuple_cat(tuple<_TElements...>&& __t, const tuple<_UElements...>& __u)
711  {
712  return __tuple_cat_helper(std::move(__t), typename
713  __make_index_holder<_TElements...>::type(),
714  __u, typename
715  __make_index_holder<_UElements...>::type());
716  }
717 
718  template<typename... _TElements, typename... _UElements>
719  inline tuple<_TElements..., _UElements...>
720  tuple_cat(const tuple<_TElements...>& __t, tuple<_UElements...>&& __u)
721  {
722  return __tuple_cat_helper(__t, typename
723  __make_index_holder<_TElements...>::type(),
724  std::move(__u), typename
725  __make_index_holder<_UElements...>::type());
726  }
727 
728  template<typename... _TElements, typename... _UElements>
729  inline tuple<_TElements..., _UElements...>
730  tuple_cat(tuple<_TElements...>&& __t, tuple<_UElements...>&& __u)
731  {
732  return __tuple_cat_helper(std::move(__t), typename
733  __make_index_holder<_TElements...>::type(),
734  std::move(__u), typename
735  __make_index_holder<_UElements...>::type());
736  }
737 
738  template<typename... _Elements>
739  inline tuple<_Elements&...>
740  tie(_Elements&... __args)
741  { return tuple<_Elements&...>(__args...); }
742 
743  template<typename... _Elements>
744  inline void
745  swap(tuple<_Elements...>& __x, tuple<_Elements...>& __y)
746  { __x.swap(__y); }
747 
748  // A class (and instance) which can be used in 'tie' when an element
749  // of a tuple is not required
750  struct _Swallow_assign
751  {
752  template<class _Tp>
753  const _Swallow_assign&
754  operator=(const _Tp&) const
755  { return *this; }
756  };
757 
758  const _Swallow_assign ignore{};
759 
760  /**
761  * Stores a tuple of indices. Used by bind() to extract the elements
762  * in a tuple.
763  */
764  template<int... _Indexes>
766  {
767  typedef _Index_tuple<_Indexes..., sizeof...(_Indexes)> __next;
768  };
769 
770  /// Builds an _Index_tuple<0, 1, 2, ..., _Num-1>.
771  template<std::size_t _Num>
773  {
774  typedef typename _Build_index_tuple<_Num-1>::__type::__next __type;
775  };
776 
777  template<>
778  struct _Build_index_tuple<0>
779  {
780  typedef _Index_tuple<> __type;
781  };
782 
783  // See stl_pair.h...
784  template<class _T1, class _T2>
785  template<typename _Tp, typename... _Args>
786  inline _Tp
787  pair<_T1, _T2>::
788  __cons(tuple<_Args...>&& __tuple)
789  {
790  typedef typename _Build_index_tuple<sizeof...(_Args)>::__type
791  _Indexes;
792  return __do_cons<_Tp>(std::move(__tuple), _Indexes());
793  }
794 
795  template<class _T1, class _T2>
796  template<typename _Tp, typename... _Args, int... _Indexes>
797  inline _Tp
798  pair<_T1, _T2>::
799  __do_cons(tuple<_Args...>&& __tuple,
800  const _Index_tuple<_Indexes...>&)
801  { return _Tp(std::forward<_Args>(get<_Indexes>(__tuple))...); }
802 
803 _GLIBCXX_END_NAMESPACE_VERSION
804 } // namespace
805 
806 #endif // __GXX_EXPERIMENTAL_CXX0X__
807 
808 #endif // _GLIBCXX_TUPLE
Struct holding two objects of arbitrary type.
Definition: stl_pair.h:87
_T1 first
second_type is the second bound type
Definition: stl_pair.h:92
Builds an _Index_tuple<0, 1, 2, ..., _Num-1>.
Definition: tuple:772
tuple
Definition: tuple:230
tuple_element
Definition: array:245
tuple_size
Definition: array:241
enable_if
Definition: type_traits:836
_Tp && forward(typename std::remove_reference< _Tp >::type &__t)
forward (as per N3143)
Definition: move.h:62
_T2 second
first is a copy of the first object
Definition: stl_pair.h:93