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_FIND_LAST_H
10#define _LIBCPP___ALGORITHM_RANGES_FIND_LAST_H
11
12#include <__config>
13#include <__functional/identity.h>
14#include <__functional/invoke.h>
15#include <__functional/ranges_operations.h>
16#include <__iterator/concepts.h>
17#include <__iterator/indirectly_comparable.h>
18#include <__iterator/next.h>
19#include <__iterator/prev.h>
20#include <__iterator/projected.h>
21#include <__ranges/access.h>
22#include <__ranges/concepts.h>
23#include <__ranges/subrange.h>
24#include <__utility/forward.h>
25#include <__utility/move.h>
26
27#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
28# pragma GCC system_header
29#endif
30
31_LIBCPP_PUSH_MACROS
32#include <__undef_macros>
33
34#if _LIBCPP_STD_VER >= 23
35
36_LIBCPP_BEGIN_NAMESPACE_STD
37
38namespace ranges {
39
40template <class _Iter, class _Sent, class _Pred, class _Proj>
41constexpr subrange<_Iter> __find_last_impl(_Iter __first, _Sent __last, _Pred __pred, _Proj& __proj) {
42 if (__first == __last) {
43 return subrange<_Iter>(__first, __first);
44 }
45
46 if constexpr (bidirectional_iterator<_Iter>) {
47 auto __last_it = ranges::next(__first, __last);
48 for (auto __it = ranges::prev(__last_it); __it != __first; --__it) {
49 if (__pred(std::invoke(__proj, *__it))) {
50 return subrange<_Iter>(std::move(__it), std::move(__last_it));
51 }
52 }
53 if (__pred(std::invoke(__proj, *__first))) {
54 return subrange<_Iter>(std::move(__first), std::move(__last_it));
55 }
56 return subrange<_Iter>(__last_it, __last_it);
57 } else {
58 bool __found = false;
59 _Iter __found_it;
60 for (; __first != __last; ++__first) {
61 if (__pred(std::invoke(__proj, *__first))) {
62 __found = true;
63 __found_it = __first;
64 }
65 }
66
67 if (__found) {
68 return subrange<_Iter>(std::move(__found_it), std::move(__first));
69 } else {
70 return subrange<_Iter>(__first, __first);
71 }
72 }
73}
74
75struct __find_last {
76 template <class _Type>
77 struct __op {
78 const _Type& __value;
79 template <class _Elem>
80 constexpr decltype(auto) operator()(_Elem&& __elem) const {
81 return std::forward<_Elem>(__elem) == __value;
82 }
83 };
84
85 template <forward_iterator _Iter, sentinel_for<_Iter> _Sent, class _Type, class _Proj = identity>
86 requires indirect_binary_predicate<ranges::equal_to, projected<_Iter, _Proj>, const _Type*>
87 [[nodiscard]] constexpr static subrange<_Iter>
88 operator()(_Iter __first, _Sent __last, const _Type& __value, _Proj __proj = {}) {
89 return ranges::__find_last_impl(std::move(__first), std::move(__last), __op<_Type>{__value}, __proj);
90 }
91
92 template <forward_range _Range, class _Type, class _Proj = identity>
93 requires indirect_binary_predicate<ranges::equal_to, projected<iterator_t<_Range>, _Proj>, const _Type*>
94 [[nodiscard]] constexpr static borrowed_subrange_t<_Range>
95 operator()(_Range&& __range, const _Type& __value, _Proj __proj = {}) {
96 return ranges::__find_last_impl(ranges::begin(__range), ranges::end(__range), __op<_Type>{__value}, __proj);
97 }
98};
99
100struct __find_last_if {
101 template <class _Pred>
102 struct __op {
103 _Pred& __pred;
104 template <class _Elem>
105 constexpr decltype(auto) operator()(_Elem&& __elem) const {
106 return std::invoke(__pred, std::forward<_Elem>(__elem));
107 }
108 };
109
110 template <forward_iterator _Iter,
111 sentinel_for<_Iter> _Sent,
112 class _Proj = identity,
113 indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
114 [[nodiscard]] constexpr static subrange<_Iter>
115 operator()(_Iter __first, _Sent __last, _Pred __pred, _Proj __proj = {}) {
116 return ranges::__find_last_impl(std::move(__first), std::move(__last), __op<_Pred>{__pred}, __proj);
117 }
118
119 template <forward_range _Range,
120 class _Proj = identity,
121 indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>> _Pred>
122 [[nodiscard]] constexpr static borrowed_subrange_t<_Range>
123 operator()(_Range&& __range, _Pred __pred, _Proj __proj = {}) {
124 return ranges::__find_last_impl(ranges::begin(__range), ranges::end(__range), __op<_Pred>{__pred}, __proj);
125 }
126};
127
128struct __find_last_if_not {
129 template <class _Pred>
130 struct __op {
131 _Pred& __pred;
132 template <class _Elem>
133 constexpr decltype(auto) operator()(_Elem&& __elem) const {
134 return !std::invoke(__pred, std::forward<_Elem>(__elem));
135 }
136 };
137
138 template <forward_iterator _Iter,
139 sentinel_for<_Iter> _Sent,
140 class _Proj = identity,
141 indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
142 [[nodiscard]] constexpr static subrange<_Iter>
143 operator()(_Iter __first, _Sent __last, _Pred __pred, _Proj __proj = {}) {
144 return ranges::__find_last_impl(std::move(__first), std::move(__last), __op<_Pred>{__pred}, __proj);
145 }
146
147 template <forward_range _Range,
148 class _Proj = identity,
149 indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>> _Pred>
150 [[nodiscard]] constexpr static borrowed_subrange_t<_Range>
151 operator()(_Range&& __range, _Pred __pred, _Proj __proj = {}) {
152 return ranges::__find_last_impl(ranges::begin(__range), ranges::end(__range), __op<_Pred>{__pred}, __proj);
153 }
154};
155
156inline namespace __cpo {
157inline constexpr auto find_last = __find_last{};
158inline constexpr auto find_last_if = __find_last_if{};
159inline constexpr auto find_last_if_not = __find_last_if_not{};
160} // namespace __cpo
161} // namespace ranges
162
163_LIBCPP_END_NAMESPACE_STD
164
165#endif // _LIBCPP_STD_VER >= 23
166
167_LIBCPP_POP_MACROS
168
169#endif // _LIBCPP___ALGORITHM_RANGES_FIND_LAST_H
170