libstdc++
experimental/array
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1 // <experimental/array> -*- C++ -*-
2 
3 // Copyright (C) 2015-2021 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
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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 
40 namespace std _GLIBCXX_VISIBILITY(default)
41 {
42 _GLIBCXX_BEGIN_NAMESPACE_VERSION
43 
44 namespace experimental
45 {
46 inline 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 
59 template<typename _Dest, typename... _Types>
60  struct __make_array_elem
61  {
62  using type = _Dest;
63  };
64 
65 template<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.
83 template <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 
91 template <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.
99 template <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
integral_constant< bool, true > true_type
The type used as a compile-time boolean with true value.
Definition: type_traits:83
typename remove_cv< _Tp >::type remove_cv_t
Alias template for remove_cv.
Definition: type_traits:1584
integral_constant< bool, false > false_type
The type used as a compile-time boolean with false value.
Definition: type_traits:86
constexpr array< remove_cv_t< _Tp >, _Nm > to_array(_Tp(&__a)[_Nm]) noexcept(is_nothrow_constructible< remove_cv_t< _Tp >, _Tp & >::value)
Create a std::array from an array.
constexpr array< typename __make_array_elem< _Dest, _Types... >::type, sizeof...(_Types)> make_array(_Types &&... __t)
Create a std::array from a variable-length list of arguments.
ISO C++ entities toplevel namespace is std.
A standard container for storing a fixed size sequence of elements.
Definition: array:96
is_nothrow_constructible
Definition: type_traits:1024
Class template integer_sequence.
Definition: utility:323