libstdc++-v3/include/experimental/array

   1 // <experimental/array> -*- C++ -*-
   2
   3 // Copyright (C) 2015-2016 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 <= 201103L
  35 # include <bits/c++14_warning.h>
  36 #else
  37
  38 #include <array>
  39 #include <functional>
  40 #include <experimental/type_traits>
  41
  42 namespace std _GLIBCXX_VISIBILITY(default)
  43 {
  44 namespace experimental
  45 {
  46 inline namespace fundamentals_v2
  47 {
  48 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  49
  50 #define __cpp_lib_experimental_make_array 201505
  51   /**
  52    * @defgroup make_array Array creation functions
  53    * @ingroup experimental
  54    *
  55    * Array creation functions as described in N4529,
  56    * Working Draft, C++ Extensions for Library Fundamentals, Version 2
  57    *
  58    * @{
  59    */
  60
  61 template <typename _Up>
  62   struct __is_reference_wrapper : false_type
  63   {};
  64
  65 template <typename _Up>
  66   struct __is_reference_wrapper<reference_wrapper<_Up>> : true_type
  67   {};
  68
  69 template <typename _Dest = void, typename... _Types>
  70   constexpr auto
  71   make_array(_Types&&... __t)
  72     -> array<conditional_t<is_void_v<_Dest>,
  73                            common_type_t<_Types...>,
  74                            _Dest>,
  75              sizeof...(_Types)>
  76   {
  77     static_assert(__or_<
  78                   __not_<is_void<_Dest>>,
  79                   __and_<__not_<__is_reference_wrapper<decay_t<_Types>>>...>>
  80                   ::value,
  81                   "make_array cannot be used without an explicit target type "
  82                   "if any of the types given is a reference_wrapper");
  83     return {{forward<_Types>(__t)...}};
  84   }
  85
  86 template <typename _Tp, size_t _Nm, size_t... _Idx>
  87   constexpr array<remove_cv_t<_Tp>, _Nm>
  88   __to_array(_Tp (&__a)[_Nm],
  89              index_sequence<_Idx...>)
  90   {
  91     return {{__a[_Idx]...}};
  92   }
  93
  94 template <typename _Tp, size_t _Nm>
  95   constexpr array<remove_cv_t<_Tp>, _Nm>
  96   to_array(_Tp (&__a)[_Nm])
  97   {
  98     return __to_array(__a, make_index_sequence<_Nm>{});
  99   }
 100
 101   // @} group make_array
 102   _GLIBCXX_END_NAMESPACE_VERSION
 103 } // namespace fundamentals_v2
 104 } // namespace experimental
 105
 106 } // namespace std
 107
 108 #endif // C++14
 109
 110 #endif // _GLIBCXX_EXPERIMENTAL_ARRAY