xref: /freebsd/contrib/llvm-project/libcxx/include/__utility/in_place.h (revision cb14a3fe5122c879eae1fb480ed7ce82a699ddb6)
1fe6060f1SDimitry Andric //===----------------------------------------------------------------------===//
2fe6060f1SDimitry Andric //
3fe6060f1SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4fe6060f1SDimitry Andric // See https://llvm.org/LICENSE.txt for license information.
5fe6060f1SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6fe6060f1SDimitry Andric //
7fe6060f1SDimitry Andric //===----------------------------------------------------------------------===//
8fe6060f1SDimitry Andric 
9fe6060f1SDimitry Andric #ifndef _LIBCPP___UTILITY_IN_PLACE_H
10fe6060f1SDimitry Andric #define _LIBCPP___UTILITY_IN_PLACE_H
11fe6060f1SDimitry Andric 
12fe6060f1SDimitry Andric #include <__config>
13bdd1243dSDimitry Andric #include <__type_traits/remove_cvref.h>
14bdd1243dSDimitry Andric #include <cstddef>
15fe6060f1SDimitry Andric 
16fe6060f1SDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
17fe6060f1SDimitry Andric #  pragma GCC system_header
18fe6060f1SDimitry Andric #endif
19fe6060f1SDimitry Andric 
20fe6060f1SDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD
21fe6060f1SDimitry Andric 
2206c3fb27SDimitry Andric #if _LIBCPP_STD_VER >= 17
23fe6060f1SDimitry Andric 
2406c3fb27SDimitry Andric struct _LIBCPP_EXPORTED_FROM_ABI in_place_t {
25fe6060f1SDimitry Andric   explicit in_place_t() = default;
26fe6060f1SDimitry Andric };
27349cc55cSDimitry Andric inline constexpr in_place_t in_place{};
28fe6060f1SDimitry Andric 
29fe6060f1SDimitry Andric template <class _Tp>
30fe6060f1SDimitry Andric struct _LIBCPP_TEMPLATE_VIS in_place_type_t {
3106c3fb27SDimitry Andric   _LIBCPP_HIDE_FROM_ABI explicit in_place_type_t() = default;
32fe6060f1SDimitry Andric };
33fe6060f1SDimitry Andric template <class _Tp>
34349cc55cSDimitry Andric inline constexpr in_place_type_t<_Tp> in_place_type{};
35fe6060f1SDimitry Andric 
36fe6060f1SDimitry Andric template <size_t _Idx>
37fe6060f1SDimitry Andric struct _LIBCPP_TEMPLATE_VIS in_place_index_t {
3806c3fb27SDimitry Andric   _LIBCPP_HIDE_FROM_ABI explicit in_place_index_t() = default;
39fe6060f1SDimitry Andric };
40fe6060f1SDimitry Andric template <size_t _Idx>
41349cc55cSDimitry Andric inline constexpr in_place_index_t<_Idx> in_place_index{};
42fe6060f1SDimitry Andric 
43*cb14a3feSDimitry Andric template <class _Tp>
44*cb14a3feSDimitry Andric struct __is_inplace_type_imp : false_type {};
45*cb14a3feSDimitry Andric template <class _Tp>
46*cb14a3feSDimitry Andric struct __is_inplace_type_imp<in_place_type_t<_Tp>> : true_type {};
47fe6060f1SDimitry Andric 
48fe6060f1SDimitry Andric template <class _Tp>
49bdd1243dSDimitry Andric using __is_inplace_type = __is_inplace_type_imp<__remove_cvref_t<_Tp>>;
50fe6060f1SDimitry Andric 
51*cb14a3feSDimitry Andric template <class _Tp>
52*cb14a3feSDimitry Andric struct __is_inplace_index_imp : false_type {};
53*cb14a3feSDimitry Andric template <size_t _Idx>
54*cb14a3feSDimitry Andric struct __is_inplace_index_imp<in_place_index_t<_Idx>> : true_type {};
55fe6060f1SDimitry Andric 
56fe6060f1SDimitry Andric template <class _Tp>
57bdd1243dSDimitry Andric using __is_inplace_index = __is_inplace_index_imp<__remove_cvref_t<_Tp>>;
58fe6060f1SDimitry Andric 
5906c3fb27SDimitry Andric #endif // _LIBCPP_STD_VER >= 17
60fe6060f1SDimitry Andric 
61fe6060f1SDimitry Andric _LIBCPP_END_NAMESPACE_STD
62fe6060f1SDimitry Andric 
63fe6060f1SDimitry Andric #endif // _LIBCPP___UTILITY_IN_PLACE_H
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