libstdc++-v3/include/experimental/tuple

   1 // <experimental/tuple> -*- C++ -*-
   2
   3 // Copyright (C) 2014-2019 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 experimental/tuple
  26  *  This is a TS C++ Library header.
  27  */
  28
  29 #ifndef _GLIBCXX_EXPERIMENTAL_TUPLE
  30 #define _GLIBCXX_EXPERIMENTAL_TUPLE 1
  31
  32 #pragma GCC system_header
  33
  34 #if __cplusplus >= 201402L
  35
  36 #include <tuple>
  37 #include <bits/invoke.h>
  38 #include <experimental/bits/lfts_config.h>
  39
  40 namespace std _GLIBCXX_VISIBILITY(default)
  41 {
  42 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  43
  44 namespace experimental
  45 {
  46 inline namespace fundamentals_v1
  47 {
  48   // See C++14 §20.4.2.5, tuple helper classes
  49   template <typename _Tp>
  50     constexpr size_t tuple_size_v = tuple_size<_Tp>::value;
  51
  52 #define __cpp_lib_experimental_tuple 201402
  53
  54   template <typename _Fn, typename _Tuple, std::size_t... _Idx>
  55     constexpr decltype(auto)
  56     __apply_impl(_Fn&& __f, _Tuple&& __t, std::index_sequence<_Idx...>)
  57     {
  58       return std::__invoke(std::forward<_Fn>(__f),
  59                            std::get<_Idx>(std::forward<_Tuple>(__t))...);
  60     }
  61
  62   template <typename _Fn, typename _Tuple>
  63     constexpr decltype(auto)
  64     apply(_Fn&& __f, _Tuple&& __t)
  65     {
  66       using _Indices =
  67         std::make_index_sequence<tuple_size_v<std::decay_t<_Tuple>>>;
  68       return experimental::__apply_impl(std::forward<_Fn>(__f),
  69                                         std::forward<_Tuple>(__t),
  70                                         _Indices{});
  71     }
  72 } // namespace fundamentals_v1
  73 } // namespace experimental
  74
  75 _GLIBCXX_END_NAMESPACE_VERSION
  76 } // namespace std
  77
  78 #endif // C++14
  79
  80 #endif // _GLIBCXX_EXPERIMENTAL_TUPLE