libstdc++-v3/include/bits/move.h

   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 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 <bits/concept_check.h>
  35
  36 _GLIBCXX_BEGIN_NAMESPACE(std)
  37
  38   // Used, in C++03 mode too, by allocators, etc.
  39   template<typename _Tp>
  40     inline _Tp*
  41     __addressof(_Tp& __r)
  42     {
  43       return reinterpret_cast<_Tp*>
  44         (&const_cast<char&>(reinterpret_cast<const volatile char&>(__r)));
  45     }
  46
  47 _GLIBCXX_END_NAMESPACE
  48
  49 #ifdef __GXX_EXPERIMENTAL_CXX0X__
  50 #include <type_traits> // Brings in std::declval too.
  51
  52 _GLIBCXX_BEGIN_NAMESPACE(std)
  53
  54   /// forward (as per N3143)
  55   template<typename _Tp>
  56     inline _Tp&&
  57     forward(typename std::remove_reference<_Tp>::type& __t)
  58     { return static_cast<_Tp&&>(__t); }
  59
  60   template<typename _Tp>
  61     inline _Tp&&
  62     forward(typename std::remove_reference<_Tp>::type&& __t)
  63     {
  64       static_assert(!std::is_lvalue_reference<_Tp>::value, "template argument"
  65                     " substituting _Tp is an lvalue reference type");
  66       return static_cast<_Tp&&>(__t);
  67     }
  68
  69   /**
  70    *  @brief Move a value.
  71    *  @ingroup mutating_algorithms
  72    *  @param  __t  A thing of arbitrary type.
  73    *  @return Same, moved.
  74   */
  75   template<typename _Tp>
  76     inline typename std::remove_reference<_Tp>::type&&
  77     move(_Tp&& __t)
  78     { return static_cast<typename std::remove_reference<_Tp>::type&&>(__t); }
  79
  80   /// declval, from type_traits.
  81
  82   /**
  83    *  @brief Returns the actual address of the object or function
  84    *         referenced by r, even in the presence of an overloaded
  85    *         operator&.
  86    *  @param  __r  Reference to an object or function.
  87    *  @return   The actual address.
  88   */
  89   template<typename _Tp>
  90     inline _Tp*
  91     addressof(_Tp& __r)
  92     { return std::__addressof(__r); }
  93
  94 _GLIBCXX_END_NAMESPACE
  95
  96 #define _GLIBCXX_MOVE(__val) std::move(__val)
  97 #define _GLIBCXX_FORWARD(_Tp, __val) std::forward<_Tp>(__val)
  98 #else
  99 #define _GLIBCXX_MOVE(__val) (__val)
 100 #define _GLIBCXX_FORWARD(_Tp, __val) (__val)
 101 #endif
 102
 103 _GLIBCXX_BEGIN_NAMESPACE(std)
 104
 105   /**
 106    *  @brief Swaps two values.
 107    *  @ingroup mutating_algorithms
 108    *  @param  __a  A thing of arbitrary type.
 109    *  @param  __b  Another thing of arbitrary type.
 110    *  @return   Nothing.
 111   */
 112   template<typename _Tp>
 113     inline void
 114     swap(_Tp& __a, _Tp& __b)
 115     {
 116       // concept requirements
 117       __glibcxx_function_requires(_SGIAssignableConcept<_Tp>)
 118
 119       _Tp __tmp = _GLIBCXX_MOVE(__a);
 120       __a = _GLIBCXX_MOVE(__b);
 121       __b = _GLIBCXX_MOVE(__tmp);
 122     }
 123
 124   // _GLIBCXX_RESOLVE_LIB_DEFECTS
 125   // DR 809. std::swap should be overloaded for array types.
 126   template<typename _Tp, size_t _Nm>
 127     inline void
 128     swap(_Tp (&__a)[_Nm], _Tp (&__b)[_Nm])
 129     {
 130       for (size_t __n = 0; __n < _Nm; ++__n)
 131         swap(__a[__n], __b[__n]);
 132     }
 133
 134 _GLIBCXX_END_NAMESPACE
 135
 136 #endif /* _MOVE_H */