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_DISJUNCTION_H 10 #define _LIBCPP___TYPE_TRAITS_DISJUNCTION_H 11 12 #include <__config> 13 #include <__type_traits/conditional.h> 14 #include <__type_traits/integral_constant.h> 15 16 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 17 # pragma GCC system_header 18 #endif 19 20 _LIBCPP_BEGIN_NAMESPACE_STD 21 22 template <bool> 23 struct _OrImpl; 24 25 template <> 26 struct _OrImpl<true> { 27 template <class _Res, class _First, class... _Rest> 28 using _Result _LIBCPP_NODEBUG = 29 typename _OrImpl<!bool(_First::value) && sizeof...(_Rest) != 0>::template _Result<_First, _Rest...>; 30 }; 31 32 template <> 33 struct _OrImpl<false> { 34 template <class _Res, class...> 35 using _Result = _Res; 36 }; 37 38 template <class... _Args> 39 using _Or _LIBCPP_NODEBUG = typename _OrImpl<sizeof...(_Args) != 0>::template _Result<false_type, _Args...>; 40 41 #if _LIBCPP_STD_VER > 14 42 43 template <class... _Args> 44 struct disjunction : _Or<_Args...> {}; 45 46 template <class... _Args> 47 inline constexpr bool disjunction_v = _Or<_Args...>::value; 48 49 #endif // _LIBCPP_STD_VER > 14 50 51 _LIBCPP_END_NAMESPACE_STD 52 53 #endif // _LIBCPP___TYPE_TRAITS_DISJUNCTION_H 54