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___TYPE_TRAITS_IS_SWAPPABLE_H 10 #define _LIBCPP___TYPE_TRAITS_IS_SWAPPABLE_H 11 12 #include <__config> 13 #include <__cstddef/size_t.h> 14 #include <__type_traits/add_lvalue_reference.h> 15 #include <__type_traits/enable_if.h> 16 #include <__type_traits/integral_constant.h> 17 #include <__type_traits/is_assignable.h> 18 #include <__type_traits/is_constructible.h> 19 #include <__type_traits/is_nothrow_assignable.h> 20 #include <__type_traits/is_nothrow_constructible.h> 21 #include <__type_traits/void_t.h> 22 #include <__utility/declval.h> 23 24 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 25 # pragma GCC system_header 26 #endif 27 28 _LIBCPP_BEGIN_NAMESPACE_STD 29 30 template <class _Tp, class _Up, class = void> 31 inline const bool __is_swappable_with_v = false; 32 33 template <class _Tp> 34 inline const bool __is_swappable_v = __is_swappable_with_v<_Tp&, _Tp&>; 35 36 template <class _Tp, class _Up, bool = __is_swappable_with_v<_Tp, _Up> > 37 inline const bool __is_nothrow_swappable_with_v = false; 38 39 template <class _Tp> 40 inline const bool __is_nothrow_swappable_v = __is_nothrow_swappable_with_v<_Tp&, _Tp&>; 41 42 #ifndef _LIBCPP_CXX03_LANG 43 template <class _Tp> 44 using __swap_result_t _LIBCPP_NODEBUG = 45 __enable_if_t<is_move_constructible<_Tp>::value && is_move_assignable<_Tp>::value>; 46 #else 47 template <class> 48 using __swap_result_t _LIBCPP_NODEBUG = void; 49 #endif 50 51 template <class _Tp> 52 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __swap_result_t<_Tp> swap(_Tp& __x, _Tp& __y) 53 _NOEXCEPT_(is_nothrow_move_constructible<_Tp>::value&& is_nothrow_move_assignable<_Tp>::value); 54 55 template <class _Tp, size_t _Np, __enable_if_t<__is_swappable_v<_Tp>, int> = 0> 56 inline _LIBCPP_HIDE_FROM_ABI 57 _LIBCPP_CONSTEXPR_SINCE_CXX20 void swap(_Tp (&__a)[_Np], _Tp (&__b)[_Np]) _NOEXCEPT_(__is_nothrow_swappable_v<_Tp>); 58 59 // ALL generic swap overloads MUST already have a declaration available at this point. 60 61 template <class _Tp, class _Up> 62 inline const bool __is_swappable_with_v<_Tp, 63 _Up, 64 __void_t<decltype(swap(std::declval<_Tp>(), std::declval<_Up>())), 65 decltype(swap(std::declval<_Up>(), std::declval<_Tp>()))> > = true; 66 67 #ifndef _LIBCPP_CXX03_LANG // C++03 doesn't have noexcept, so things are never nothrow swappable 68 template <class _Tp, class _Up> 69 inline const bool __is_nothrow_swappable_with_v<_Tp, _Up, true> = 70 noexcept(swap(std::declval<_Tp>(), std::declval<_Up>())) && 71 noexcept(swap(std::declval<_Up>(), std::declval<_Tp>())); 72 #endif 73 74 #if _LIBCPP_STD_VER >= 17 75 76 template <class _Tp, class _Up> 77 _LIBCPP_NO_SPECIALIZATIONS inline constexpr bool is_swappable_with_v = __is_swappable_with_v<_Tp, _Up>; 78 79 template <class _Tp, class _Up> 80 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_NO_SPECIALIZATIONS is_swappable_with 81 : bool_constant<is_swappable_with_v<_Tp, _Up>> {}; 82 83 template <class _Tp> 84 _LIBCPP_NO_SPECIALIZATIONS inline constexpr bool is_swappable_v = 85 is_swappable_with_v<__add_lvalue_reference_t<_Tp>, __add_lvalue_reference_t<_Tp>>; 86 87 template <class _Tp> 88 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_NO_SPECIALIZATIONS is_swappable : bool_constant<is_swappable_v<_Tp>> {}; 89 90 template <class _Tp, class _Up> 91 _LIBCPP_NO_SPECIALIZATIONS inline constexpr bool is_nothrow_swappable_with_v = __is_nothrow_swappable_with_v<_Tp, _Up>; 92 93 template <class _Tp, class _Up> 94 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_NO_SPECIALIZATIONS is_nothrow_swappable_with 95 : bool_constant<is_nothrow_swappable_with_v<_Tp, _Up>> {}; 96 97 template <class _Tp> 98 _LIBCPP_NO_SPECIALIZATIONS inline constexpr bool is_nothrow_swappable_v = 99 is_nothrow_swappable_with_v<__add_lvalue_reference_t<_Tp>, __add_lvalue_reference_t<_Tp>>; 100 101 template <class _Tp> 102 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_NO_SPECIALIZATIONS is_nothrow_swappable 103 : bool_constant<is_nothrow_swappable_v<_Tp>> {}; 104 105 #endif // _LIBCPP_STD_VER >= 17 106 107 _LIBCPP_END_NAMESPACE_STD 108 109 #endif // _LIBCPP___TYPE_TRAITS_IS_SWAPPABLE_H 110