1// <experimental/array> -*- C++ -*-
2
3// Copyright (C) 2015-2020 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/array
26 *  This is a TS C++ Library header.
27 *  @ingroup libfund-ts
28 */
29
30#ifndef _GLIBCXX_EXPERIMENTAL_ARRAY
31#define _GLIBCXX_EXPERIMENTAL_ARRAY 1
32
33#pragma GCC system_header
34
35#if __cplusplus >= 201402L
36
37#include <array>
38#include <experimental/type_traits>
39
40namespace std _GLIBCXX_VISIBILITY(default)
41{
42_GLIBCXX_BEGIN_NAMESPACE_VERSION
43
44namespace experimental
45{
46inline namespace fundamentals_v2
47{
48#define __cpp_lib_experimental_make_array 201505
49  /**
50   * @defgroup make_array Array creation functions
51   * @ingroup libfund-ts
52   *
53   * Array creation functions as described in N4529,
54   * Working Draft, C++ Extensions for Library Fundamentals, Version 2
55   *
56   * @{
57   */
58
59template<typename _Dest, typename... _Types>
60  struct __make_array_elem
61  {
62    using type = _Dest;
63  };
64
65template<typename... _Types>
66  struct __make_array_elem<void, _Types...>
67  : common_type<_Types...>
68  {
69    template <typename>
70      struct __is_reference_wrapper : false_type
71      {};
72
73    template <typename _Up>
74      struct __is_reference_wrapper<reference_wrapper<_Up>> : true_type
75      {};
76
77    static_assert(!__or_<__is_reference_wrapper<decay_t<_Types>>...>::value,
78                  "make_array must be used with an explicit target type when"
79                  "any of the arguments is a reference_wrapper");
80  };
81
82/// Create a std::array from a variable-length list of arguments.
83template <typename _Dest = void, typename... _Types>
84  constexpr
85  array<typename __make_array_elem<_Dest, _Types...>::type, sizeof...(_Types)>
86  make_array(_Types&&... __t)
87  {
88    return {{ std::forward<_Types>(__t)... }};
89  }
90
91template <typename _Tp, size_t _Nm, size_t... _Idx>
92  constexpr array<remove_cv_t<_Tp>, _Nm>
93  __to_array(_Tp (&__a)[_Nm], index_sequence<_Idx...>)
94  {
95    return {{__a[_Idx]...}};
96  }
97
98/// Create a std::array from an array.
99template <typename _Tp, size_t _Nm>
100  constexpr array<remove_cv_t<_Tp>, _Nm>
101  to_array(_Tp (&__a)[_Nm])
102  noexcept(is_nothrow_constructible<remove_cv_t<_Tp>, _Tp&>::value)
103  {
104    return experimental::__to_array(__a, make_index_sequence<_Nm>{});
105  }
106
107  /// @} group make_array
108} // namespace fundamentals_v2
109} // namespace experimental
110
111_GLIBCXX_END_NAMESPACE_VERSION
112} // namespace std
113
114#endif // C++14
115
116#endif // _GLIBCXX_EXPERIMENTAL_ARRAY
117