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_CONVERTIBLE_H 10 #define _LIBCPP___TYPE_TRAITS_IS_CONVERTIBLE_H 11 12 #include <__config> 13 #include <__type_traits/integral_constant.h> 14 #include <__type_traits/is_array.h> 15 #include <__type_traits/is_function.h> 16 #include <__type_traits/is_void.h> 17 #include <__type_traits/remove_reference.h> 18 #include <__utility/declval.h> 19 #include <cstddef> 20 21 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 22 # pragma GCC system_header 23 #endif 24 25 _LIBCPP_BEGIN_NAMESPACE_STD 26 27 #if __has_builtin(__is_convertible_to) && !defined(_LIBCPP_USE_IS_CONVERTIBLE_FALLBACK) 28 29 template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS is_convertible 30 : public integral_constant<bool, __is_convertible_to(_T1, _T2)> {}; 31 32 #else // __has_builtin(__is_convertible_to) && !defined(_LIBCPP_USE_IS_CONVERTIBLE_FALLBACK) 33 34 namespace __is_convertible_imp 35 { 36 template <class _Tp> void __test_convert(_Tp); 37 38 template <class _From, class _To, class = void> 39 struct __is_convertible_test : public false_type {}; 40 41 template <class _From, class _To> 42 struct __is_convertible_test<_From, _To, 43 decltype(__is_convertible_imp::__test_convert<_To>(declval<_From>()))> : public true_type 44 {}; 45 46 template <class _Tp, bool _IsArray = is_array<_Tp>::value, 47 bool _IsFunction = is_function<_Tp>::value, 48 bool _IsVoid = is_void<_Tp>::value> 49 struct __is_array_function_or_void {enum {value = 0};}; 50 template <class _Tp> struct __is_array_function_or_void<_Tp, true, false, false> {enum {value = 1};}; 51 template <class _Tp> struct __is_array_function_or_void<_Tp, false, true, false> {enum {value = 2};}; 52 template <class _Tp> struct __is_array_function_or_void<_Tp, false, false, true> {enum {value = 3};}; 53 } 54 55 template <class _Tp, 56 unsigned = __is_convertible_imp::__is_array_function_or_void<typename remove_reference<_Tp>::type>::value> 57 struct __is_convertible_check 58 { 59 static const size_t __v = 0; 60 }; 61 62 template <class _Tp> 63 struct __is_convertible_check<_Tp, 0> 64 { 65 static const size_t __v = sizeof(_Tp); 66 }; 67 68 template <class _T1, class _T2, 69 unsigned _T1_is_array_function_or_void = __is_convertible_imp::__is_array_function_or_void<_T1>::value, 70 unsigned _T2_is_array_function_or_void = __is_convertible_imp::__is_array_function_or_void<_T2>::value> 71 struct __is_convertible 72 : public integral_constant<bool, 73 __is_convertible_imp::__is_convertible_test<_T1, _T2>::value 74 > 75 {}; 76 77 template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 1> : public false_type {}; 78 template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 1> : public false_type {}; 79 template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 1> : public false_type {}; 80 template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 1> : public false_type {}; 81 82 template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 2> : public false_type {}; 83 template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 2> : public false_type {}; 84 template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 2> : public false_type {}; 85 template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 2> : public false_type {}; 86 87 template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 3> : public false_type {}; 88 template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 3> : public false_type {}; 89 template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 3> : public false_type {}; 90 template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 3> : public true_type {}; 91 92 template <class _T1, class _T2> struct _LIBCPP_TEMPLATE_VIS is_convertible 93 : public __is_convertible<_T1, _T2> 94 { 95 static const size_t __complete_check1 = __is_convertible_check<_T1>::__v; 96 static const size_t __complete_check2 = __is_convertible_check<_T2>::__v; 97 }; 98 99 #endif // __has_builtin(__is_convertible_to) && !defined(_LIBCPP_USE_IS_CONVERTIBLE_FALLBACK) 100 101 #if _LIBCPP_STD_VER > 14 102 template <class _From, class _To> 103 inline constexpr bool is_convertible_v = is_convertible<_From, _To>::value; 104 #endif 105 106 _LIBCPP_END_NAMESPACE_STD 107 108 #endif // _LIBCPP___TYPE_TRAITS_IS_CONVERTIBLE_H 109