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

   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 */