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___ALGORITHM_PSTL_FRONTEND_DISPATCH 10 #define _LIBCPP___ALGORITHM_PSTL_FRONTEND_DISPATCH 11 12 #include <__config> 13 #include <__type_traits/is_callable.h> 14 #include <__utility/forward.h> 15 16 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 17 # pragma GCC system_header 18 #endif 19 20 #if _LIBCPP_STD_VER >= 17 21 22 _LIBCPP_BEGIN_NAMESPACE_STD 23 24 # define _LIBCPP_PSTL_CUSTOMIZATION_POINT(name, policy) \ 25 [](auto&&... __args) -> decltype(std::name<policy>( \ 26 typename __select_backend<policy>::type{}, std::forward<decltype(__args)>(__args)...)) { \ 27 return std::name<policy>(typename __select_backend<policy>::type{}, std::forward<decltype(__args)>(__args)...); \ 28 } 29 30 template <class _SpecializedImpl, class _GenericImpl, class... _Args> 31 _LIBCPP_HIDE_FROM_ABI decltype(auto) 32 __pstl_frontend_dispatch(_SpecializedImpl __specialized_impl, _GenericImpl __generic_impl, _Args&&... __args) { 33 if constexpr (__is_callable<_SpecializedImpl, _Args...>::value) { 34 return __specialized_impl(std::forward<_Args>(__args)...); 35 } else { 36 return __generic_impl(std::forward<_Args>(__args)...); 37 } 38 } 39 40 _LIBCPP_END_NAMESPACE_STD 41 42 #endif // _LIBCPP_STD_VER >= 17 43 44 #endif // _LIBCPP___ALGORITHM_PSTL_FRONTEND_DISPATCH 45