libstdc++-v3/include/experimental/tuple

   1 // <experimental/tuple> -*- C++ -*-
   2
   3 // Copyright (C) 2014-2020 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