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_CONJUNCTION_H 10 #define _LIBCPP___TYPE_TRAITS_CONJUNCTION_H 11 12 #include <__config> 13 #include <__type_traits/conditional.h> 14 #include <__type_traits/enable_if.h> 15 #include <__type_traits/integral_constant.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 > 14 24 25 template <class _Arg, class... _Args> 26 struct __conjunction_impl { 27 using type = conditional_t<!bool(_Arg::value), _Arg, typename __conjunction_impl<_Args...>::type>; 28 }; 29 30 template <class _Arg> 31 struct __conjunction_impl<_Arg> { 32 using type = _Arg; 33 }; 34 35 template <class... _Args> 36 struct conjunction : __conjunction_impl<true_type, _Args...>::type {}; 37 38 template<class... _Args> 39 inline constexpr bool conjunction_v = conjunction<_Args...>::value; 40 41 #endif // _LIBCPP_STD_VER > 14 42 43 template <class...> 44 using __expand_to_true = true_type; 45 46 template <class... _Pred> 47 __expand_to_true<__enable_if_t<_Pred::value>...> __and_helper(int); 48 49 template <class...> 50 false_type __and_helper(...); 51 52 template <class... _Pred> 53 using _And _LIBCPP_NODEBUG = decltype(__and_helper<_Pred...>(0)); 54 55 _LIBCPP_END_NAMESPACE_STD 56 57 #endif // _LIBCPP___TYPE_TRAITS_CONJUNCTION_H 58