| //===----------------------------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef _LIBCPP___ALGORITHM_MAKE_PROJECTED_H |
| #define _LIBCPP___ALGORITHM_MAKE_PROJECTED_H |
| |
| #include <__concepts/same_as.h> |
| #include <__config> |
| #include <__functional/identity.h> |
| #include <__functional/invoke.h> |
| #include <__type_traits/decay.h> |
| #include <__type_traits/enable_if.h> |
| #include <__type_traits/integral_constant.h> |
| #include <__type_traits/is_member_pointer.h> |
| #include <__type_traits/is_same.h> |
| #include <__utility/declval.h> |
| #include <__utility/forward.h> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| # pragma GCC system_header |
| #endif |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| template <class _Pred, class _Proj> |
| struct _ProjectedPred { |
| _Pred& __pred; // Can be a unary or a binary predicate. |
| _Proj& __proj; |
| |
| _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI _ProjectedPred(_Pred& __pred_arg, _Proj& __proj_arg) |
| : __pred(__pred_arg), __proj(__proj_arg) {} |
| |
| template <class _Tp> |
| typename __invoke_of<_Pred&, |
| decltype(std::__invoke(std::declval<_Proj&>(), std::declval<_Tp>())) |
| >::type |
| _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI operator()(_Tp&& __v) const { |
| return std::__invoke(__pred, std::__invoke(__proj, std::forward<_Tp>(__v))); |
| } |
| |
| template <class _T1, class _T2> |
| typename __invoke_of<_Pred&, |
| decltype(std::__invoke(std::declval<_Proj&>(), std::declval<_T1>())), |
| decltype(std::__invoke(std::declval<_Proj&>(), std::declval<_T2>())) |
| >::type |
| _LIBCPP_CONSTEXPR _LIBCPP_HIDE_FROM_ABI operator()(_T1&& __lhs, _T2&& __rhs) const { |
| return std::__invoke(__pred, |
| std::__invoke(__proj, std::forward<_T1>(__lhs)), |
| std::__invoke(__proj, std::forward<_T2>(__rhs))); |
| } |
| |
| }; |
| |
| template <class _Pred, |
| class _Proj, |
| __enable_if_t<!(!is_member_pointer<__decay_t<_Pred> >::value && |
| __is_identity<__decay_t<_Proj> >::value), |
| int> = 0> |
| _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _ProjectedPred<_Pred, _Proj> |
| __make_projected(_Pred& __pred, _Proj& __proj) { |
| return _ProjectedPred<_Pred, _Proj>(__pred, __proj); |
| } |
| |
| // Avoid creating the functor and just use the pristine comparator -- for certain algorithms, this would enable |
| // optimizations that rely on the type of the comparator. Additionally, this results in less layers of indirection in |
| // the call stack when the comparator is invoked, even in an unoptimized build. |
| template <class _Pred, |
| class _Proj, |
| __enable_if_t<!is_member_pointer<__decay_t<_Pred> >::value && |
| __is_identity<__decay_t<_Proj> >::value, |
| int> = 0> |
| _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _Pred& __make_projected(_Pred& __pred, _Proj&) { |
| return __pred; |
| } |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| #if _LIBCPP_STD_VER >= 20 |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| namespace ranges { |
| |
| template <class _Comp, class _Proj1, class _Proj2> |
| _LIBCPP_HIDE_FROM_ABI constexpr |
| decltype(auto) __make_projected_comp(_Comp& __comp, _Proj1& __proj1, _Proj2& __proj2) { |
| if constexpr (__is_identity<decay_t<_Proj1>>::value && __is_identity<decay_t<_Proj2>>::value && |
| !is_member_pointer_v<decay_t<_Comp>>) { |
| // Avoid creating the lambda and just use the pristine comparator -- for certain algorithms, this would enable |
| // optimizations that rely on the type of the comparator. |
| return __comp; |
| |
| } else { |
| return [&](auto&& __lhs, auto&& __rhs) { |
| return std::invoke(__comp, |
| std::invoke(__proj1, std::forward<decltype(__lhs)>(__lhs)), |
| std::invoke(__proj2, std::forward<decltype(__rhs)>(__rhs))); |
| }; |
| } |
| } |
| |
| } // namespace ranges |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| #endif // _LIBCPP_STD_VER >= 20 |
| |
| #endif // _LIBCPP___ALGORITHM_MAKE_PROJECTED_H |