1// Move, forward and identity for C++0x + swap -*- C++ -*-
2
3// Copyright (C) 2007, 2008, 2009, 2010 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 bits/move.h
26 *  This is an internal header file, included by other library headers.
27 *  Do not attempt to use it directly. @headername{utility}
28 */
29
30#ifndef _MOVE_H
31#define _MOVE_H 1
32
33#include <bits/c++config.h>
34#include <bits/concept_check.h>
35
36namespace std _GLIBCXX_VISIBILITY(default)
37{
38_GLIBCXX_BEGIN_NAMESPACE_VERSION
39
40  // Used, in C++03 mode too, by allocators, etc.
41  template<typename _Tp>
42    inline _Tp*
43    __addressof(_Tp& __r)
44    {
45      return reinterpret_cast<_Tp*>
46	(&const_cast<char&>(reinterpret_cast<const volatile char&>(__r)));
47    }
48
49_GLIBCXX_END_NAMESPACE_VERSION
50} // namespace
51
52#ifdef __GXX_EXPERIMENTAL_CXX0X__
53#include <type_traits> // Brings in std::declval too.
54
55namespace std _GLIBCXX_VISIBILITY(default)
56{
57_GLIBCXX_BEGIN_NAMESPACE_VERSION
58
59  /// forward (as per N3143)
60  template<typename _Tp>
61    inline _Tp&&
62    forward(typename std::remove_reference<_Tp>::type& __t)
63    { return static_cast<_Tp&&>(__t); }
64
65  template<typename _Tp>
66    inline _Tp&&
67    forward(typename std::remove_reference<_Tp>::type&& __t)
68    {
69      static_assert(!std::is_lvalue_reference<_Tp>::value, "template argument"
70		    " substituting _Tp is an lvalue reference type");
71      return static_cast<_Tp&&>(__t);
72    }
73
74  /**
75   *  @brief Move a value.
76   *  @ingroup mutating_algorithms
77   *  @param  __t  A thing of arbitrary type.
78   *  @return Same, moved.
79  */
80  template<typename _Tp>
81    inline typename std::remove_reference<_Tp>::type&&
82    move(_Tp&& __t)
83    { return static_cast<typename std::remove_reference<_Tp>::type&&>(__t); }
84
85  /// declval, from type_traits.
86
87  /**
88   *  @brief Returns the actual address of the object or function
89   *         referenced by r, even in the presence of an overloaded
90   *         operator&.
91   *  @param  __r  Reference to an object or function.
92   *  @return   The actual address.
93  */
94  template<typename _Tp>
95    inline _Tp*
96    addressof(_Tp& __r)
97    { return std::__addressof(__r); }
98
99_GLIBCXX_END_NAMESPACE_VERSION
100} // namespace
101
102#define _GLIBCXX_MOVE(__val) std::move(__val)
103#define _GLIBCXX_FORWARD(_Tp, __val) std::forward<_Tp>(__val)
104#else
105#define _GLIBCXX_MOVE(__val) (__val)
106#define _GLIBCXX_FORWARD(_Tp, __val) (__val)
107#endif
108
109namespace std _GLIBCXX_VISIBILITY(default)
110{
111_GLIBCXX_BEGIN_NAMESPACE_VERSION
112
113  /**
114   *  @brief Swaps two values.
115   *  @ingroup mutating_algorithms
116   *  @param  __a  A thing of arbitrary type.
117   *  @param  __b  Another thing of arbitrary type.
118   *  @return   Nothing.
119  */
120  template<typename _Tp>
121    inline void
122    swap(_Tp& __a, _Tp& __b)
123    {
124      // concept requirements
125      __glibcxx_function_requires(_SGIAssignableConcept<_Tp>)
126
127      _Tp __tmp = _GLIBCXX_MOVE(__a);
128      __a = _GLIBCXX_MOVE(__b);
129      __b = _GLIBCXX_MOVE(__tmp);
130    }
131
132  // _GLIBCXX_RESOLVE_LIB_DEFECTS
133  // DR 809. std::swap should be overloaded for array types.
134  template<typename _Tp, size_t _Nm>
135    inline void
136    swap(_Tp (&__a)[_Nm], _Tp (&__b)[_Nm])
137    {
138      for (size_t __n = 0; __n < _Nm; ++__n)
139	swap(__a[__n], __b[__n]);
140    }
141
142_GLIBCXX_END_NAMESPACE_VERSION
143} // namespace
144
145#endif /* _MOVE_H */
146