libstdc++
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00001 // Implementation of INVOKE -*- C++ -*- 00002 00003 // Copyright (C) 2016-2018 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 include/bits/invoke.h 00026 * This is an internal header file, included by other library headers. 00027 * Do not attempt to use it directly. @headername{functional} 00028 */ 00029 00030 #ifndef _GLIBCXX_INVOKE_H 00031 #define _GLIBCXX_INVOKE_H 1 00032 00033 #pragma GCC system_header 00034 00035 #if __cplusplus < 201103L 00036 # include <bits/c++0x_warning.h> 00037 #else 00038 00039 #include <type_traits> 00040 00041 namespace std _GLIBCXX_VISIBILITY(default) 00042 { 00043 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00044 00045 /** 00046 * @addtogroup utilities 00047 * @{ 00048 */ 00049 00050 // Used by __invoke_impl instead of std::forward<_Tp> so that a 00051 // reference_wrapper is converted to an lvalue-reference. 00052 template<typename _Tp, typename _Up = typename __inv_unwrap<_Tp>::type> 00053 constexpr _Up&& 00054 __invfwd(typename remove_reference<_Tp>::type& __t) noexcept 00055 { return static_cast<_Up&&>(__t); } 00056 00057 template<typename _Res, typename _Fn, typename... _Args> 00058 constexpr _Res 00059 __invoke_impl(__invoke_other, _Fn&& __f, _Args&&... __args) 00060 { return std::forward<_Fn>(__f)(std::forward<_Args>(__args)...); } 00061 00062 template<typename _Res, typename _MemFun, typename _Tp, typename... _Args> 00063 constexpr _Res 00064 __invoke_impl(__invoke_memfun_ref, _MemFun&& __f, _Tp&& __t, 00065 _Args&&... __args) 00066 { return (__invfwd<_Tp>(__t).*__f)(std::forward<_Args>(__args)...); } 00067 00068 template<typename _Res, typename _MemFun, typename _Tp, typename... _Args> 00069 constexpr _Res 00070 __invoke_impl(__invoke_memfun_deref, _MemFun&& __f, _Tp&& __t, 00071 _Args&&... __args) 00072 { 00073 return ((*std::forward<_Tp>(__t)).*__f)(std::forward<_Args>(__args)...); 00074 } 00075 00076 template<typename _Res, typename _MemPtr, typename _Tp> 00077 constexpr _Res 00078 __invoke_impl(__invoke_memobj_ref, _MemPtr&& __f, _Tp&& __t) 00079 { return __invfwd<_Tp>(__t).*__f; } 00080 00081 template<typename _Res, typename _MemPtr, typename _Tp> 00082 constexpr _Res 00083 __invoke_impl(__invoke_memobj_deref, _MemPtr&& __f, _Tp&& __t) 00084 { return (*std::forward<_Tp>(__t)).*__f; } 00085 00086 /// Invoke a callable object. 00087 template<typename _Callable, typename... _Args> 00088 constexpr typename __invoke_result<_Callable, _Args...>::type 00089 __invoke(_Callable&& __fn, _Args&&... __args) 00090 noexcept(__is_nothrow_invocable<_Callable, _Args...>::value) 00091 { 00092 using __result = __invoke_result<_Callable, _Args...>; 00093 using __type = typename __result::type; 00094 using __tag = typename __result::__invoke_type; 00095 return std::__invoke_impl<__type>(__tag{}, std::forward<_Callable>(__fn), 00096 std::forward<_Args>(__args)...); 00097 } 00098 00099 _GLIBCXX_END_NAMESPACE_VERSION 00100 } // namespace std 00101 00102 #endif // C++11 00103 00104 #endif // _GLIBCXX_INVOKE_H