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1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP___ALGORITHM_FIND_END_OF_H
11#define _LIBCPP___ALGORITHM_FIND_END_OF_H
12
13#include <__algorithm/comp.h>
14#include <__algorithm/iterator_operations.h>
15#include <__config>
16#include <__functional/identity.h>
17#include <__iterator/iterator_traits.h>
18#include <__type_traits/invoke.h>
19#include <__utility/pair.h>
20
21#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
22# pragma GCC system_header
23#endif
24
25_LIBCPP_BEGIN_NAMESPACE_STD
26
27template < class _AlgPolicy,
28 class _Iter1,
29 class _Sent1,
30 class _Iter2,
31 class _Sent2,
32 class _Pred,
33 class _Proj1,
34 class _Proj2>
35_LIBCPP_HIDE_FROM_ABI inline _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_Iter1, _Iter1> __find_end_impl(
36 _Iter1 __first1,
37 _Sent1 __last1,
38 _Iter2 __first2,
39 _Sent2 __last2,
40 _Pred& __pred,
41 _Proj1& __proj1,
42 _Proj2& __proj2,
43 forward_iterator_tag,
44 forward_iterator_tag) {
45 // modeled after search algorithm
46 _Iter1 __match_first = _IterOps<_AlgPolicy>::next(__first1, __last1); // __last1 is the "default" answer
47 _Iter1 __match_last = __match_first;
48 if (__first2 == __last2)
49 return pair<_Iter1, _Iter1>(__match_last, __match_last);
50 while (true) {
51 while (true) {
52 if (__first1 == __last1) // if source exhausted return last correct answer (or __last1 if never found)
53 return pair<_Iter1, _Iter1>(__match_first, __match_last);
54 if (std::__invoke(__pred, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
55 break;
56 ++__first1;
57 }
58 // *__first1 matches *__first2, now match elements after here
59 _Iter1 __m1 = __first1;
60 _Iter2 __m2 = __first2;
61 while (true) {
62 if (++__m2 == __last2) { // Pattern exhaused, record answer and search for another one
63 __match_first = __first1;
64 __match_last = ++__m1;
65 ++__first1;
66 break;
67 }
68 if (++__m1 == __last1) // Source exhausted, return last answer
69 return pair<_Iter1, _Iter1>(__match_first, __match_last);
70 // mismatch, restart with a new __first
71 if (!std::__invoke(__pred, std::__invoke(__proj1, *__m1), std::__invoke(__proj2, *__m2))) {
72 ++__first1;
73 break;
74 } // else there is a match, check next elements
75 }
76 }
77}
78
79template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
80[[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator1 __find_end_classic(
81 _ForwardIterator1 __first1,
82 _ForwardIterator1 __last1,
83 _ForwardIterator2 __first2,
84 _ForwardIterator2 __last2,
85 _BinaryPredicate& __pred) {
86 auto __proj = __identity();
87 return std::__find_end_impl<_ClassicAlgPolicy>(
88 __first1,
89 __last1,
90 __first2,
91 __last2,
92 __pred,
93 __proj,
94 __proj,
95 typename iterator_traits<_ForwardIterator1>::iterator_category(),
96 typename iterator_traits<_ForwardIterator2>::iterator_category())
97 .first;
98}
99
100template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
101[[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator1 find_end(
102 _ForwardIterator1 __first1,
103 _ForwardIterator1 __last1,
104 _ForwardIterator2 __first2,
105 _ForwardIterator2 __last2,
106 _BinaryPredicate __pred) {
107 return std::__find_end_classic(__first1, __last1, __first2, __last2, __pred);
108}
109
110template <class _ForwardIterator1, class _ForwardIterator2>
111[[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator1
112find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2) {
113 return std::find_end(__first1, __last1, __first2, __last2, __equal_to());
114}
115
116_LIBCPP_END_NAMESPACE_STD
117
118#endif // _LIBCPP___ALGORITHM_FIND_END_OF_H