libcxx/include/__algorithm/ranges_max_element.h

   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_RANGES_MAX_ELEMENT_H
  10 #define _LIBCPP___ALGORITHM_RANGES_MAX_ELEMENT_H
  11
  12 #include <__algorithm/ranges_min_element.h>
  13 #include <__config>
  14 #include <__functional/identity.h>
  15 #include <__functional/invoke.h>
  16 #include <__functional/ranges_operations.h>
  17 #include <__iterator/concepts.h>
  18 #include <__iterator/projected.h>
  19 #include <__ranges/access.h>
  20 #include <__ranges/concepts.h>
  21 #include <__ranges/dangling.h>
  22
  23 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  24 #  pragma GCC system_header
  25 #endif
  26
  27 #if _LIBCPP_STD_VER >= 20
  28
  29 _LIBCPP_BEGIN_NAMESPACE_STD
  30
  31 namespace ranges {
  32 namespace __max_element {
  33 struct __fn {
  34   template <forward_iterator _Ip,
  35             sentinel_for<_Ip> _Sp,
  36             class _Proj                                             = identity,
  37             indirect_strict_weak_order<projected<_Ip, _Proj>> _Comp = ranges::less>
  38   _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr _Ip
  39   operator()(_Ip __first, _Sp __last, _Comp __comp = {}, _Proj __proj = {}) const {
  40     auto __comp_lhs_rhs_swapped = [&](auto&& __lhs, auto&& __rhs) { return std::invoke(__comp, __rhs, __lhs); };
  41     return ranges::__min_element_impl(__first, __last, __comp_lhs_rhs_swapped, __proj);
  42   }
  43
  44   template <forward_range _Rp,
  45             class _Proj                                                         = identity,
  46             indirect_strict_weak_order<projected<iterator_t<_Rp>, _Proj>> _Comp = ranges::less>
  47   _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr borrowed_iterator_t<_Rp>
  48   operator()(_Rp&& __r, _Comp __comp = {}, _Proj __proj = {}) const {
  49     auto __comp_lhs_rhs_swapped = [&](auto&& __lhs, auto&& __rhs) { return std::invoke(__comp, __rhs, __lhs); };
  50     return ranges::__min_element_impl(ranges::begin(__r), ranges::end(__r), __comp_lhs_rhs_swapped, __proj);
  51   }
  52 };
  53 } // namespace __max_element
  54
  55 inline namespace __cpo {
  56 inline constexpr auto max_element = __max_element::__fn{};
  57 } // namespace __cpo
  58 } // namespace ranges
  59
  60 _LIBCPP_END_NAMESPACE_STD
  61
  62 #endif // _LIBCPP_STD_VER >= 20
  63
  64 #endif // _LIBCPP___ALGORITHM_RANGES_MAX_ELEMENT_H