libstdc++
move.h
Go to the documentation of this file.
1 // Move, forward and identity for C++0x + swap -*- C++ -*-
2 
3 // Copyright (C) 2007, 2008, 2009 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 move.h
26  * This is an internal header file, included by other library headers.
27  * You should not attempt to use it directly.
28  */
29 
30 #ifndef _MOVE_H
31 #define _MOVE_H 1
32 
33 #include <bits/c++config.h>
34 #include <cstddef>
35 #include <bits/concept_check.h>
36 
37 #ifdef __GXX_EXPERIMENTAL_CXX0X__
38 #include <type_traits>
39 
40 _GLIBCXX_BEGIN_NAMESPACE(std)
41 
42  // 20.2.2, forward/move
43  template<typename _Tp>
44  struct identity
45  {
46  typedef _Tp type;
47  };
48 
49  template<typename _Tp>
50  inline _Tp&&
51  forward(typename std::identity<_Tp>::type&& __t)
52  { return __t; }
53 
54  template<typename _Tp>
55  inline typename std::remove_reference<_Tp>::type&&
56  move(_Tp&& __t)
57  { return __t; }
58 
59 _GLIBCXX_END_NAMESPACE
60 
61 #define _GLIBCXX_MOVE(_Tp) std::move(_Tp)
62 #else
63 #define _GLIBCXX_MOVE(_Tp) (_Tp)
64 #endif
65 
66 _GLIBCXX_BEGIN_NAMESPACE(std)
67 
68  /**
69  * @brief Swaps two values.
70  * @param a A thing of arbitrary type.
71  * @param b Another thing of arbitrary type.
72  * @return Nothing.
73  */
74  template<typename _Tp>
75  inline void
76  swap(_Tp& __a, _Tp& __b)
77  {
78  // concept requirements
79  __glibcxx_function_requires(_SGIAssignableConcept<_Tp>)
80 
81  _Tp __tmp = _GLIBCXX_MOVE(__a);
82  __a = _GLIBCXX_MOVE(__b);
83  __b = _GLIBCXX_MOVE(__tmp);
84  }
85 
86  // _GLIBCXX_RESOLVE_LIB_DEFECTS
87  // DR 809. std::swap should be overloaded for array types.
88  template<typename _Tp, size_t _Nm>
89  inline void
90  swap(_Tp (&__a)[_Nm], _Tp (&__b)[_Nm])
91  {
92  for (size_t __n = 0; __n < _Nm; ++__n)
93  swap(__a[__n], __b[__n]);
94  }
95 
96 _GLIBCXX_END_NAMESPACE
97 
98 #endif /* _MOVE_H */