libcxx/include/__algorithm/ranges_max_element.h

//===----------------------------------------------------------------------===//
//
// 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_RANGES_MAX_ELEMENT_H
#define _LIBCPP___ALGORITHM_RANGES_MAX_ELEMENT_H

#include <__algorithm/min_element.h>
#include <__config>
#include <__functional/identity.h>
#include <__functional/invoke.h>
#include <__functional/ranges_operations.h>
#include <__iterator/concepts.h>
#include <__iterator/projected.h>
#include <__ranges/access.h>
#include <__ranges/concepts.h>
#include <__ranges/dangling.h>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#  pragma GCC system_header
#endif

_LIBCPP_PUSH_MACROS
#include <__undef_macros>

#if _LIBCPP_STD_VER >= 20

_LIBCPP_BEGIN_NAMESPACE_STD

namespace ranges {
struct __max_element {
  template <forward_iterator _Ip,
            sentinel_for<_Ip> _Sp,
            class _Proj                                             = identity,
            indirect_strict_weak_order<projected<_Ip, _Proj>> _Comp = ranges::less>
  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr _Ip
  operator()(_Ip __first, _Sp __last, _Comp __comp = {}, _Proj __proj = {}) const {
    auto __comp_lhs_rhs_swapped = [&](auto&& __lhs, auto&& __rhs) -> bool { return std::invoke(__comp, __rhs, __lhs); };
    return std::__min_element(__first, __last, __comp_lhs_rhs_swapped, __proj);
  }

  template <forward_range _Rp,
            class _Proj                                                         = identity,
            indirect_strict_weak_order<projected<iterator_t<_Rp>, _Proj>> _Comp = ranges::less>
  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr borrowed_iterator_t<_Rp>
  operator()(_Rp&& __r, _Comp __comp = {}, _Proj __proj = {}) const {
    auto __comp_lhs_rhs_swapped = [&](auto&& __lhs, auto&& __rhs) -> bool { return std::invoke(__comp, __rhs, __lhs); };
    return std::__min_element(ranges::begin(__r), ranges::end(__r), __comp_lhs_rhs_swapped, __proj);
  }
};

inline namespace __cpo {
inline constexpr auto max_element = __max_element{};
} // namespace __cpo
} // namespace ranges

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP_STD_VER >= 20

_LIBCPP_POP_MACROS

#endif // _LIBCPP___ALGORITHM_RANGES_MAX_ELEMENT_H