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      1 // <experimental/tuple> -*- C++ -*-
      2 
      3 // Copyright (C) 2014-2024 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 #include <bits/requires_hosted.h> // experimental is currently omitted
     36 
     37 #if __cplusplus >= 201402L
     38 
     39 #include <tuple>
     40 #include <bits/invoke.h>
     41 #include <experimental/bits/lfts_config.h>
     42 
     43 namespace std _GLIBCXX_VISIBILITY(default)
     44 {
     45 _GLIBCXX_BEGIN_NAMESPACE_VERSION
     46 
     47 namespace experimental
     48 {
     49 inline namespace fundamentals_v1
     50 {
     51   // See C++14 20.4.2.5, tuple helper classes
     52   template <typename _Tp>
     53     constexpr size_t tuple_size_v = tuple_size<_Tp>::value;
     54 
     55 #define __cpp_lib_experimental_tuple 201402
     56 
     57   template <typename _Fn, typename _Tuple, std::size_t... _Idx>
     58     constexpr decltype(auto)
     59     __apply_impl(_Fn&& __f, _Tuple&& __t, std::index_sequence<_Idx...>)
     60     {
     61       return std::__invoke(std::forward<_Fn>(__f),
     62 			   std::get<_Idx>(std::forward<_Tuple>(__t))...);
     63     }
     64 
     65   template <typename _Fn, typename _Tuple>
     66     constexpr decltype(auto)
     67     apply(_Fn&& __f, _Tuple&& __t)
     68     {
     69       using _Indices =
     70 	std::make_index_sequence<tuple_size_v<std::decay_t<_Tuple>>>;
     71       return experimental::__apply_impl(std::forward<_Fn>(__f),
     72 					std::forward<_Tuple>(__t),
     73 					_Indices{});
     74     }
     75 } // namespace fundamentals_v1
     76 } // namespace experimental
     77 
     78 _GLIBCXX_END_NAMESPACE_VERSION
     79 } // namespace std
     80 
     81 #endif // C++14
     82 
     83 #endif // _GLIBCXX_EXPERIMENTAL_TUPLE
     84