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      1 // <experimental/tuple> -*- C++ -*-
      2 
      3 // Copyright (C) 2014-2022 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 experimental/tuple
     26  *  This is a TS C++ Library header.
     27  *  @ingroup libfund-ts
     28  */
     29 
     30 #ifndef _GLIBCXX_EXPERIMENTAL_TUPLE
     31 #define _GLIBCXX_EXPERIMENTAL_TUPLE 1
     32 
     33 #pragma GCC system_header
     34 
     35 #if __cplusplus >= 201402L
     36 
     37 #include <tuple>
     38 #include <bits/invoke.h>
     39 #include <experimental/bits/lfts_config.h>
     40 
     41 namespace std _GLIBCXX_VISIBILITY(default)
     42 {
     43 _GLIBCXX_BEGIN_NAMESPACE_VERSION
     44 
     45 namespace experimental
     46 {
     47 inline namespace fundamentals_v1
     48 {
     49   // See C++14 20.4.2.5, tuple helper classes
     50   template <typename _Tp>
     51     constexpr size_t tuple_size_v = tuple_size<_Tp>::value;
     52 
     53 #define __cpp_lib_experimental_tuple 201402
     54 
     55   template <typename _Fn, typename _Tuple, std::size_t... _Idx>
     56     constexpr decltype(auto)
     57     __apply_impl(_Fn&& __f, _Tuple&& __t, std::index_sequence<_Idx...>)
     58     {
     59       return std::__invoke(std::forward<_Fn>(__f),
     60 			   std::get<_Idx>(std::forward<_Tuple>(__t))...);
     61     }
     62 
     63   template <typename _Fn, typename _Tuple>
     64     constexpr decltype(auto)
     65     apply(_Fn&& __f, _Tuple&& __t)
     66     {
     67       using _Indices =
     68 	std::make_index_sequence<tuple_size_v<std::decay_t<_Tuple>>>;
     69       return experimental::__apply_impl(std::forward<_Fn>(__f),
     70 					std::forward<_Tuple>(__t),
     71 					_Indices{});
     72     }
     73 } // namespace fundamentals_v1
     74 } // namespace experimental
     75 
     76 _GLIBCXX_END_NAMESPACE_VERSION
     77 } // namespace std
     78 
     79 #endif // C++14
     80 
     81 #endif // _GLIBCXX_EXPERIMENTAL_TUPLE
     82