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) && !defined(_LIBCPP_USE_IS_CONVERTIBLE_FALLBACK) 28 29 template <class _T1, class _T2> 30 struct _LIBCPP_TEMPLATE_VIS is_convertible : public integral_constant<bool, __is_convertible(_T1, _T2)> {}; 31 32 #elif __has_builtin(__is_convertible_to) && !defined(_LIBCPP_USE_IS_CONVERTIBLE_FALLBACK) 33 34 template <class _T1, class _T2> 35 struct _LIBCPP_TEMPLATE_VIS is_convertible : public integral_constant<bool, __is_convertible_to(_T1, _T2)> {}; 36 37 // TODO: Remove this fallback when GCC < 13 support is no longer required. 38 // GCC 13 has the __is_convertible built-in. 39 #else // __has_builtin(__is_convertible_to) && !defined(_LIBCPP_USE_IS_CONVERTIBLE_FALLBACK) 40 41 namespace __is_convertible_imp { 42 template <class _Tp> 43 void __test_convert(_Tp); 44 45 template <class _From, class _To, class = void> 46 struct __is_convertible_test : public false_type {}; 47 48 template <class _From, class _To> 49 struct __is_convertible_test<_From, _To, decltype(__is_convertible_imp::__test_convert<_To>(std::declval<_From>()))> 50 : public true_type {}; 51 52 // clang-format off 53 template <class _Tp, 54 bool _IsArray = is_array<_Tp>::value, 55 bool _IsFunction = is_function<_Tp>::value, 56 bool _IsVoid = is_void<_Tp>::value> 57 struct __is_array_function_or_void { enum { value = 0 }; }; 58 template <class _Tp> struct __is_array_function_or_void<_Tp, true, false, false> { enum { value = 1 }; }; 59 template <class _Tp> struct __is_array_function_or_void<_Tp, false, true, false> { enum { value = 2 }; }; 60 template <class _Tp> struct __is_array_function_or_void<_Tp, false, false, true> { enum { value = 3 }; }; 61 // clang-format on 62 } // namespace __is_convertible_imp 63 64 template <class _Tp, 65 unsigned = __is_convertible_imp::__is_array_function_or_void<__libcpp_remove_reference_t<_Tp> >::value> 66 struct __is_convertible_check { 67 static const size_t __v = 0; 68 }; 69 70 template <class _Tp> 71 struct __is_convertible_check<_Tp, 0> { 72 static const size_t __v = sizeof(_Tp); 73 }; 74 75 template <class _T1, 76 class _T2, 77 unsigned _T1_is_array_function_or_void = __is_convertible_imp::__is_array_function_or_void<_T1>::value, 78 unsigned _T2_is_array_function_or_void = __is_convertible_imp::__is_array_function_or_void<_T2>::value> 79 struct __is_convertible 80 : public integral_constant<bool, __is_convertible_imp::__is_convertible_test<_T1, _T2>::value >{}; 81 82 // clang-format off 83 template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 1> : public false_type{}; 84 template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 1> : public false_type{}; 85 template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 1> : public false_type{}; 86 template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 1> : public false_type{}; 87 88 template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 2> : public false_type{}; 89 template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 2> : public false_type{}; 90 template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 2> : public false_type{}; 91 template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 2> : public false_type{}; 92 93 template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 0, 3> : public false_type{}; 94 template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 1, 3> : public false_type{}; 95 template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 2, 3> : public false_type{}; 96 template <class _T1, class _T2> struct __is_convertible<_T1, _T2, 3, 3> : public true_type{}; 97 // clang-format on 98 99 template <class _T1, class _T2> 100 struct _LIBCPP_TEMPLATE_VIS is_convertible : public __is_convertible<_T1, _T2> { 101 static const size_t __complete_check1 = __is_convertible_check<_T1>::__v; 102 static const size_t __complete_check2 = __is_convertible_check<_T2>::__v; 103 }; 104 105 #endif // __has_builtin(__is_convertible_to) && !defined(_LIBCPP_USE_IS_CONVERTIBLE_FALLBACK) 106 107 #if _LIBCPP_STD_VER >= 17 108 template <class _From, class _To> 109 inline constexpr bool is_convertible_v = is_convertible<_From, _To>::value; 110 #endif 111 112 _LIBCPP_END_NAMESPACE_STD 113 114 #endif // _LIBCPP___TYPE_TRAITS_IS_CONVERTIBLE_H 115