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       1             : // Implementation of INVOKE -*- C++ -*-
       2             : 
       3             : // Copyright (C) 2016-2019 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 include/bits/invoke.h
      26             :  *  This is an internal header file, included by other library headers.
      27             :  *  Do not attempt to use it directly. @headername{functional}
      28             :  */
      29             : 
      30             : #ifndef _GLIBCXX_INVOKE_H
      31             : #define _GLIBCXX_INVOKE_H 1
      32             : 
      33             : #pragma GCC system_header
      34             : 
      35             : #if __cplusplus < 201103L
      36             : # include <bits/c++0x_warning.h>
      37             : #else
      38             : 
      39             : #include <type_traits>
      40             : 
      41             : namespace std _GLIBCXX_VISIBILITY(default)
      42             : {
      43             : _GLIBCXX_BEGIN_NAMESPACE_VERSION
      44             : 
      45             :   /**
      46             :    *  @addtogroup utilities
      47             :    *  @{
      48             :    */
      49             : 
      50             :   // Used by __invoke_impl instead of std::forward<_Tp> so that a
      51             :   // reference_wrapper is converted to an lvalue-reference.
      52             :   template<typename _Tp, typename _Up = typename __inv_unwrap<_Tp>::type>
      53             :     constexpr _Up&&
      54        8401 :     __invfwd(typename remove_reference<_Tp>::type& __t) noexcept
      55             :     { return static_cast<_Up&&>(__t); }
      56             : 
      57             :   template<typename _Res, typename _Fn, typename... _Args>
      58             :     constexpr _Res
      59      385096 :     __invoke_impl(__invoke_other, _Fn&& __f, _Args&&... __args)
      60      385096 :     { return std::forward<_Fn>(__f)(std::forward<_Args>(__args)...); }
      61             : 
      62             :   template<typename _Res, typename _MemFun, typename _Tp, typename... _Args>
      63             :     constexpr _Res
      64        8401 :     __invoke_impl(__invoke_memfun_ref, _MemFun&& __f, _Tp&& __t,
      65             :                   _Args&&... __args)
      66        8401 :     { return (__invfwd<_Tp>(__t).*__f)(std::forward<_Args>(__args)...); }
      67             : 
      68             :   template<typename _Res, typename _MemFun, typename _Tp, typename... _Args>
      69             :     constexpr _Res
      70             :     __invoke_impl(__invoke_memfun_deref, _MemFun&& __f, _Tp&& __t,
      71             :                   _Args&&... __args)
      72             :     {
      73             :       return ((*std::forward<_Tp>(__t)).*__f)(std::forward<_Args>(__args)...);
      74             :     }
      75             : 
      76             :   template<typename _Res, typename _MemPtr, typename _Tp>
      77             :     constexpr _Res
      78             :     __invoke_impl(__invoke_memobj_ref, _MemPtr&& __f, _Tp&& __t)
      79             :     { return __invfwd<_Tp>(__t).*__f; }
      80             : 
      81             :   template<typename _Res, typename _MemPtr, typename _Tp>
      82             :     constexpr _Res
      83             :     __invoke_impl(__invoke_memobj_deref, _MemPtr&& __f, _Tp&& __t)
      84             :     { return (*std::forward<_Tp>(__t)).*__f; }
      85             : 
      86             :   /// Invoke a callable object.
      87             :   template<typename _Callable, typename... _Args>
      88             :     constexpr typename __invoke_result<_Callable, _Args...>::type
      89      393497 :     __invoke(_Callable&& __fn, _Args&&... __args)
      90             :     noexcept(__is_nothrow_invocable<_Callable, _Args...>::value)
      91             :     {
      92             :       using __result = __invoke_result<_Callable, _Args...>;
      93             :       using __type = typename __result::type;
      94             :       using __tag = typename __result::__invoke_type;
      95      398336 :       return std::__invoke_impl<__type>(__tag{}, std::forward<_Callable>(__fn),
      96        5375 :                                         std::forward<_Args>(__args)...);
      97             :     }
      98             : 
      99             : _GLIBCXX_END_NAMESPACE_VERSION
     100             : } // namespace std
     101             : 
     102             : #endif // C++11
     103             : 
     104             : #endif // _GLIBCXX_INVOKE_H