libstdc++
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00001 // Move, forward and identity for C++0x + swap -*- C++ -*- 00002 00003 // Copyright (C) 2007, 2008, 2009 Free Software Foundation, Inc. 00004 // 00005 // This file is part of the GNU ISO C++ Library. This library is free 00006 // software; you can redistribute it and/or modify it under the 00007 // terms of the GNU General Public License as published by the 00008 // Free Software Foundation; either version 3, or (at your option) 00009 // any later version. 00010 00011 // This library is distributed in the hope that it will be useful, 00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00014 // GNU General Public License for more details. 00015 00016 // Under Section 7 of GPL version 3, you are granted additional 00017 // permissions described in the GCC Runtime Library Exception, version 00018 // 3.1, as published by the Free Software Foundation. 00019 00020 // You should have received a copy of the GNU General Public License and 00021 // a copy of the GCC Runtime Library Exception along with this program; 00022 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00023 // <http://www.gnu.org/licenses/>. 00024 00025 /** @file move.h 00026 * This is an internal header file, included by other library headers. 00027 * You should not attempt to use it directly. 00028 */ 00029 00030 #ifndef _MOVE_H 00031 #define _MOVE_H 1 00032 00033 #include <bits/c++config.h> 00034 #include <cstddef> 00035 #include <bits/concept_check.h> 00036 00037 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 00038 #include <type_traits> 00039 00040 _GLIBCXX_BEGIN_NAMESPACE(std) 00041 00042 // 20.2.2, forward/move 00043 template<typename _Tp> 00044 struct identity 00045 { 00046 typedef _Tp type; 00047 }; 00048 00049 template<typename _Tp> 00050 inline _Tp&& 00051 forward(typename std::identity<_Tp>::type&& __t) 00052 { return __t; } 00053 00054 template<typename _Tp> 00055 inline typename std::remove_reference<_Tp>::type&& 00056 move(_Tp&& __t) 00057 { return __t; } 00058 00059 _GLIBCXX_END_NAMESPACE 00060 00061 #define _GLIBCXX_MOVE(_Tp) std::move(_Tp) 00062 #else 00063 #define _GLIBCXX_MOVE(_Tp) (_Tp) 00064 #endif 00065 00066 _GLIBCXX_BEGIN_NAMESPACE(std) 00067 00068 /** 00069 * @brief Swaps two values. 00070 * @param a A thing of arbitrary type. 00071 * @param b Another thing of arbitrary type. 00072 * @return Nothing. 00073 */ 00074 template<typename _Tp> 00075 inline void 00076 swap(_Tp& __a, _Tp& __b) 00077 { 00078 // concept requirements 00079 __glibcxx_function_requires(_SGIAssignableConcept<_Tp>) 00080 00081 _Tp __tmp = _GLIBCXX_MOVE(__a); 00082 __a = _GLIBCXX_MOVE(__b); 00083 __b = _GLIBCXX_MOVE(__tmp); 00084 } 00085 00086 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00087 // DR 809. std::swap should be overloaded for array types. 00088 template<typename _Tp, size_t _Nm> 00089 inline void 00090 swap(_Tp (&__a)[_Nm], _Tp (&__b)[_Nm]) 00091 { 00092 for (size_t __n = 0; __n < _Nm; ++__n) 00093 swap(__a[__n], __b[__n]); 00094 } 00095 00096 _GLIBCXX_END_NAMESPACE 00097 00098 #endif /* _MOVE_H */