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_H
10#define _LIBCPP___ALGORITHM_RANGES_MAX_H
11
12#include <__algorithm/ranges_min_element.h>
13#include <__assert>
14#include <__concepts/copyable.h>
15#include <__config>
16#include <__functional/identity.h>
17#include <__functional/invoke.h>
18#include <__functional/ranges_operations.h>
19#include <__iterator/concepts.h>
20#include <__iterator/projected.h>
21#include <__ranges/access.h>
22#include <__ranges/concepts.h>
23#include <__utility/move.h>
24#include <initializer_list>
25
26#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
27#  pragma GCC system_header
28#endif
29
30#if _LIBCPP_STD_VER > 17
31
32_LIBCPP_PUSH_MACROS
33#include <__undef_macros>
34
35_LIBCPP_BEGIN_NAMESPACE_STD
36
37namespace ranges {
38namespace __max {
39struct __fn {
40  template <class _Tp, class _Proj = identity,
41            indirect_strict_weak_order<projected<const _Tp*, _Proj>> _Comp = ranges::less>
42  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr
43  const _Tp& operator()(const _Tp& __a, const _Tp& __b, _Comp __comp = {}, _Proj __proj = {}) const {
44    return std::invoke(__comp, std::invoke(__proj, __a), std::invoke(__proj, __b)) ? __b : __a;
45  }
46
47  template <copyable _Tp, class _Proj = identity,
48            indirect_strict_weak_order<projected<const _Tp*, _Proj>> _Comp = ranges::less>
49  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr
50  _Tp operator()(initializer_list<_Tp> __il, _Comp __comp = {}, _Proj __proj = {}) const {
51    _LIBCPP_ASSERT(__il.begin() != __il.end(), "initializer_list must contain at least one element");
52
53    auto __comp_lhs_rhs_swapped = [&](auto&& __lhs, auto&& __rhs) { return std::invoke(__comp, __rhs, __lhs); };
54    return *ranges::__min_element_impl(__il.begin(), __il.end(), __comp_lhs_rhs_swapped, __proj);
55  }
56
57  template <input_range _Rp, class _Proj = identity,
58            indirect_strict_weak_order<projected<iterator_t<_Rp>, _Proj>> _Comp = ranges::less>
59    requires indirectly_copyable_storable<iterator_t<_Rp>, range_value_t<_Rp>*>
60  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr
61  range_value_t<_Rp> operator()(_Rp&& __r, _Comp __comp = {}, _Proj __proj = {}) const {
62    auto __first = ranges::begin(__r);
63    auto __last = ranges::end(__r);
64
65    _LIBCPP_ASSERT(__first != __last, "range must contain at least one element");
66
67    if constexpr (forward_range<_Rp>) {
68      auto __comp_lhs_rhs_swapped = [&](auto&& __lhs, auto&& __rhs) { return std::invoke(__comp, __rhs, __lhs); };
69      return *ranges::__min_element_impl(std::move(__first), std::move(__last), __comp_lhs_rhs_swapped, __proj);
70    } else {
71      range_value_t<_Rp> __result = *__first;
72      while (++__first != __last) {
73        if (std::invoke(__comp, std::invoke(__proj, __result), std::invoke(__proj, *__first)))
74          __result = *__first;
75      }
76      return __result;
77    }
78  }
79};
80} // namespace __max
81
82inline namespace __cpo {
83  inline constexpr auto max = __max::__fn{};
84} // namespace __cpo
85} // namespace ranges
86
87_LIBCPP_END_NAMESPACE_STD
88
89_LIBCPP_POP_MACROS
90
91#endif // _LIBCPP_STD_VER > 17 &&
92
93#endif // _LIBCPP___ALGORITHM_RANGES_MAX_H
94