| //===----------------------------------------------------------------------===// |
| // |
| // 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 <__utility/forward.h> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| # pragma GCC system_header |
| #endif |
| |
| #if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES) |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| namespace ranges { |
| |
| template <class _Comp, class _Proj> |
| _LIBCPP_HIDE_FROM_ABI constexpr static |
| decltype(auto) __make_projected_comp(_Comp& __comp, _Proj& __proj) { |
| if constexpr (same_as<_Proj, identity>) { |
| // 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(__proj, std::forward<decltype(__lhs)>(__lhs)), |
| std::invoke(__proj, std::forward<decltype(__rhs)>(__rhs))); |
| }; |
| } |
| } |
| |
| } // namespace ranges |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| #endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES) |
| |
| #endif // _LIBCPP___ALGORITHM_MAKE_PROJECTED_H |
