1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef _LIBCPP___UTILITY_IN_PLACE_H
10#define _LIBCPP___UTILITY_IN_PLACE_H
11
12#include <__config>
13#include <__cstddef/size_t.h>
14#include <__type_traits/integral_constant.h>
15#include <__type_traits/remove_cvref.h>
16
17#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
18# pragma GCC system_header
19#endif
20
21_LIBCPP_BEGIN_NAMESPACE_STD
22
23#if _LIBCPP_STD_VER >= 17
24
25struct _LIBCPP_EXPORTED_FROM_ABI in_place_t {
26 explicit in_place_t() = default;
27};
28inline constexpr in_place_t in_place{};
29
30template <class _Tp>
31struct in_place_type_t {
32 _LIBCPP_HIDE_FROM_ABI explicit in_place_type_t() = default;
33};
34template <class _Tp>
35inline constexpr in_place_type_t<_Tp> in_place_type{};
36
37template <size_t _Idx>
38struct in_place_index_t {
39 _LIBCPP_HIDE_FROM_ABI explicit in_place_index_t() = default;
40};
41template <size_t _Idx>
42inline constexpr in_place_index_t<_Idx> in_place_index{};
43
44template <class _Tp>
45struct __is_inplace_type_imp : false_type {};
46template <class _Tp>
47struct __is_inplace_type_imp<in_place_type_t<_Tp>> : true_type {};
48
49template <class _Tp>
50using __is_inplace_type _LIBCPP_NODEBUG = __is_inplace_type_imp<__remove_cvref_t<_Tp>>;
51
52template <class _Tp>
53struct __is_inplace_index_imp : false_type {};
54template <size_t _Idx>
55struct __is_inplace_index_imp<in_place_index_t<_Idx>> : true_type {};
56
57template <class _Tp>
58using __is_inplace_index _LIBCPP_NODEBUG = __is_inplace_index_imp<__remove_cvref_t<_Tp>>;
59
60#endif // _LIBCPP_STD_VER >= 17
61
62_LIBCPP_END_NAMESPACE_STD
63
64#endif // _LIBCPP___UTILITY_IN_PLACE_H
65