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 25 struct _LIBCPP_EXPORTED_FROM_ABI in_place_t { 26 explicit in_place_t() = default; 27 }; 28 inline constexpr in_place_t in_place{}; 29 30 template <class _Tp> 31 struct _LIBCPP_TEMPLATE_VIS in_place_type_t { 32 _LIBCPP_HIDE_FROM_ABI explicit in_place_type_t() = default; 33 }; 34 template <class _Tp> 35 inline constexpr in_place_type_t<_Tp> in_place_type{}; 36 37 template <size_t _Idx> 38 struct _LIBCPP_TEMPLATE_VIS in_place_index_t { 39 _LIBCPP_HIDE_FROM_ABI explicit in_place_index_t() = default; 40 }; 41 template <size_t _Idx> 42 inline constexpr in_place_index_t<_Idx> in_place_index{}; 43 44 template <class _Tp> 45 struct __is_inplace_type_imp : false_type {}; 46 template <class _Tp> 47 struct __is_inplace_type_imp<in_place_type_t<_Tp>> : true_type {}; 48 49 template <class _Tp> 50 using __is_inplace_type _LIBCPP_NODEBUG = __is_inplace_type_imp<__remove_cvref_t<_Tp>>; 51 52 template <class _Tp> 53 struct __is_inplace_index_imp : false_type {}; 54 template <size_t _Idx> 55 struct __is_inplace_index_imp<in_place_index_t<_Idx>> : true_type {}; 56 57 template <class _Tp> 58 using __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