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1 : : // Move, forward and identity for C++0x + swap -*- C++ -*-
2 : :
3 : : // Copyright (C) 2007 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 2, 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 : : // You should have received a copy of the GNU General Public License along
17 : : // with this library; see the file COPYING. If not, write to the Free
18 : : // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
19 : : // USA.
20 : :
21 : : // As a special exception, you may use this file as part of a free software
22 : : // library without restriction. Specifically, if other files instantiate
23 : : // templates or use macros or inline functions from this file, or you compile
24 : : // this file and link it with other files to produce an executable, this
25 : : // file does not by itself cause the resulting executable to be covered by
26 : : // the GNU General Public License. This exception does not however
27 : : // invalidate any other reasons why the executable file might be covered by
28 : : // the GNU General Public License.
29 : :
30 : : /** @file stl_move.h
31 : : * This is an internal header file, included by other library headers.
32 : : * You should not attempt to use it directly.
33 : : */
34 : :
35 : : #ifndef _STL_MOVE_H
36 : : #define _STL_MOVE_H 1
37 : :
38 : : #include <bits/c++config.h>
39 : : #include <bits/concept_check.h>
40 : :
41 : : #ifdef __GXX_EXPERIMENTAL_CXX0X__
42 : : #include <type_traits>
43 : :
44 : : _GLIBCXX_BEGIN_NAMESPACE(std)
45 : :
46 : : // 20.2.2, forward/move
47 : : template<typename _Tp>
48 : : struct identity
49 : : {
50 : : typedef _Tp type;
51 : : };
52 : :
53 : : template<typename _Tp>
54 : : inline _Tp&&
55 : : forward(typename std::identity<_Tp>::type&& __t)
56 : : { return __t; }
57 : :
58 : : template<typename _Tp>
59 : : inline typename std::remove_reference<_Tp>::type&&
60 : : move(_Tp&& __t)
61 : : { return __t; }
62 : :
63 : : _GLIBCXX_END_NAMESPACE
64 : :
65 : : #define _GLIBCXX_MOVE(_Tp) std::move(_Tp)
66 : : #else
67 : : #define _GLIBCXX_MOVE(_Tp) (_Tp)
68 : : #endif
69 : :
70 : : _GLIBCXX_BEGIN_NAMESPACE(std)
71 : :
72 : : /**
73 : : * @brief Swaps two values.
74 : : * @param a A thing of arbitrary type.
75 : : * @param b Another thing of arbitrary type.
76 : : * @return Nothing.
77 : : */
78 : : template<typename _Tp>
79 : : inline void
80 : : swap(_Tp& __a, _Tp& __b)
81 : : {
82 : : // concept requirements
83 : : __glibcxx_function_requires(_SGIAssignableConcept<_Tp>)
84 : :
85 : : _Tp __tmp = _GLIBCXX_MOVE(__a);
86 : : __a = _GLIBCXX_MOVE(__b);
87 : 0 : __b = _GLIBCXX_MOVE(__tmp);
88 : : }
89 : :
90 : : _GLIBCXX_END_NAMESPACE
91 : :
92 : : #endif /* _STL_MOVE_H */
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