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            7080 :     swap(_Tp& __a, _Tp& __b)
      81                 :     {
      82                 :       // concept requirements
      83                 :       __glibcxx_function_requires(_SGIAssignableConcept<_Tp>)
      84                 : 
      85            7080 :       _Tp __tmp = _GLIBCXX_MOVE(__a);
      86            7080 :       __a = _GLIBCXX_MOVE(__b);
      87            7080 :       __b = _GLIBCXX_MOVE(__tmp);
      88            7080 :     }
      89                 : 
      90                 : _GLIBCXX_END_NAMESPACE
      91                 : 
      92                 : #endif /* _STL_MOVE_H */