libstdc++-v3/include/experimental/array

   1 // <experimental/array> -*- C++ -*-
   2
   3 // Copyright (C) 2015-2018 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/array
  26  *  This is a TS C++ Library header.
  27  */
  28
  29 #ifndef _GLIBCXX_EXPERIMENTAL_ARRAY
  30 #define _GLIBCXX_EXPERIMENTAL_ARRAY 1
  31
  32 #pragma GCC system_header
  33
  34 #if __cplusplus >= 201402L
  35
  36 #include <array>
  37 #include <experimental/type_traits>
  38
  39 namespace std _GLIBCXX_VISIBILITY(default)
  40 {
  41 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  42
  43 namespace experimental
  44 {
  45 inline namespace fundamentals_v2
  46 {
  47 #define __cpp_lib_experimental_make_array 201505
  48   /**
  49    * @defgroup make_array Array creation functions
  50    * @ingroup experimental
  51    *
  52    * Array creation functions as described in N4529,
  53    * Working Draft, C++ Extensions for Library Fundamentals, Version 2
  54    *
  55    * @{
  56    */
  57
  58 template<typename _Dest, typename... _Types>
  59   struct __make_array_elem
  60   {
  61     using type = _Dest;
  62   };
  63
  64 template<typename... _Types>
  65   struct __make_array_elem<void, _Types...>
  66   : common_type<_Types...>
  67   {
  68     template <typename>
  69       struct __is_reference_wrapper : false_type
  70       {};
  71
  72     template <typename _Up>
  73       struct __is_reference_wrapper<reference_wrapper<_Up>> : true_type
  74       {};
  75
  76     static_assert(!__or_<__is_reference_wrapper<decay_t<_Types>>...>::value,
  77                   "make_array must be used with an explicit target type when"
  78                   "any of the arguments is a reference_wrapper");
  79   };
  80
  81 template <typename _Dest = void, typename... _Types>
  82   constexpr
  83   array<typename __make_array_elem<_Dest, _Types...>::type, sizeof...(_Types)>
  84   make_array(_Types&&... __t)
  85   {
  86     return {{ std::forward<_Types>(__t)... }};
  87   }
  88
  89 template <typename _Tp, size_t _Nm, size_t... _Idx>
  90   constexpr array<remove_cv_t<_Tp>, _Nm>
  91   __to_array(_Tp (&__a)[_Nm], index_sequence<_Idx...>)
  92   {
  93     return {{__a[_Idx]...}};
  94   }
  95
  96 template <typename _Tp, size_t _Nm>
  97   constexpr array<remove_cv_t<_Tp>, _Nm>
  98   to_array(_Tp (&__a)[_Nm])
  99   noexcept(is_nothrow_constructible<remove_cv_t<_Tp>, _Tp&>::value)
 100   {
 101     return __to_array(__a, make_index_sequence<_Nm>{});
 102   }
 103
 104   // @} group make_array
 105 } // namespace fundamentals_v2
 106 } // namespace experimental
 107
 108 _GLIBCXX_END_NAMESPACE_VERSION
 109 } // namespace std
 110
 111 #endif // C++14
 112
 113 #endif // _GLIBCXX_EXPERIMENTAL_ARRAY