forked from OSchip/llvm-project
52 lines
1.6 KiB
C++
52 lines
1.6 KiB
C++
//===----------------------------------------------------------------------===//
|
|
//
|
|
// 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
|