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