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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_SEARCH_H
11#define _LIBCPP___ALGORITHM_SEARCH_H
12
13#include <__algorithm/comp.h>
14#include <__algorithm/iterator_operations.h>
15#include <__config>
16#include <__functional/identity.h>
17#include <__iterator/advance.h>
18#include <__iterator/concepts.h>
19#include <__iterator/iterator_traits.h>
20#include <__type_traits/enable_if.h>
21#include <__type_traits/invoke.h>
22#include <__type_traits/is_callable.h>
23#include <__utility/pair.h>
24
25#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
26# pragma GCC system_header
27#endif
28
29_LIBCPP_BEGIN_NAMESPACE_STD
30
31template <class _AlgPolicy,
32 class _Iter1,
33 class _Sent1,
34 class _Iter2,
35 class _Sent2,
36 class _Pred,
37 class _Proj1,
38 class _Proj2>
39_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_Iter1, _Iter1> __search_forward_impl(
40 _Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2, _Pred& __pred, _Proj1& __proj1, _Proj2& __proj2) {
41 if (__first2 == __last2)
42 return std::make_pair(__first1, __first1); // Everything matches an empty sequence
43 while (true) {
44 // Find first element in sequence 1 that matchs *__first2, with a mininum of loop checks
45 while (true) {
46 if (__first1 == __last1) { // return __last1 if no element matches *__first2
47 _IterOps<_AlgPolicy>::__advance_to(__first1, __last1);
48 return std::make_pair(__first1, __first1);
49 }
50 if (std::__invoke(__pred, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
51 break;
52 ++__first1;
53 }
54 // *__first1 matches *__first2, now match elements after here
55 _Iter1 __m1 = __first1;
56 _Iter2 __m2 = __first2;
57 while (true) {
58 if (++__m2 == __last2) // If pattern exhausted, __first1 is the answer (works for 1 element pattern)
59 return std::make_pair(__first1, ++__m1);
60 if (++__m1 == __last1) { // Otherwise if source exhaused, pattern not found
61 return std::make_pair(__m1, __m1);
62 }
63
64 // if there is a mismatch, restart with a new __first1
65 if (!std::__invoke(__pred, std::__invoke(__proj1, *__m1), std::__invoke(__proj2, *__m2))) {
66 ++__first1;
67 break;
68 } // else there is a match, check next elements
69 }
70 }
71}
72
73template <class _AlgPolicy,
74 class _Iter1,
75 class _Sent1,
76 class _Iter2,
77 class _Sent2,
78 class _Pred,
79 class _Proj1,
80 class _Proj2,
81 class _DiffT1,
82 class _DiffT2>
83_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_Iter1, _Iter1> __search_random_access_impl(
84 _Iter1 __first1,
85 _Sent1 __last1,
86 _Iter2 __first2,
87 _Sent2 __last2,
88 _Pred& __pred,
89 _Proj1& __proj1,
90 _Proj2& __proj2,
91 _DiffT1 __size1,
92 _DiffT2 __size2) {
93 const _Iter1 __s = __first1 + __size1 - _DiffT1(__size2 - 1); // Start of pattern match can't go beyond here
94
95 while (true) {
96 while (true) {
97 if (__first1 == __s) {
98 _IterOps<_AlgPolicy>::__advance_to(__first1, __last1);
99 return std::make_pair(__first1, __first1);
100 }
101 if (std::__invoke(__pred, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
102 break;
103 ++__first1;
104 }
105
106 _Iter1 __m1 = __first1;
107 _Iter2 __m2 = __first2;
108 while (true) {
109 if (++__m2 == __last2)
110 return std::make_pair(__first1, __first1 + _DiffT1(__size2));
111 ++__m1; // no need to check range on __m1 because __s guarantees we have enough source
112 if (!std::__invoke(__pred, std::__invoke(__proj1, *__m1), std::__invoke(__proj2, *__m2))) {
113 ++__first1;
114 break;
115 }
116 }
117 }
118}
119
120template <class _Iter1,
121 class _Sent1,
122 class _Iter2,
123 class _Sent2,
124 class _Pred,
125 class _Proj1,
126 class _Proj2,
127 __enable_if_t<__has_random_access_iterator_category<_Iter1>::value &&
128 __has_random_access_iterator_category<_Iter2>::value,
129 int> = 0>
130_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_Iter1, _Iter1> __search_impl(
131 _Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2, _Pred& __pred, _Proj1& __proj1, _Proj2& __proj2) {
132 auto __size2 = __last2 - __first2;
133 if (__size2 == 0)
134 return std::make_pair(__first1, __first1);
135
136 auto __size1 = __last1 - __first1;
137 if (__size1 < __size2) {
138 return std::make_pair(__last1, __last1);
139 }
140
141 return std::__search_random_access_impl<_ClassicAlgPolicy>(
142 __first1, __last1, __first2, __last2, __pred, __proj1, __proj2, __size1, __size2);
143}
144
145template <
146 class _Iter1,
147 class _Sent1,
148 class _Iter2,
149 class _Sent2,
150 class _Pred,
151 class _Proj1,
152 class _Proj2,
153 __enable_if_t<__has_forward_iterator_category<_Iter1>::value && __has_forward_iterator_category<_Iter2>::value &&
154 !(__has_random_access_iterator_category<_Iter1>::value &&
155 __has_random_access_iterator_category<_Iter2>::value),
156 int> = 0>
157_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_Iter1, _Iter1> __search_impl(
158 _Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2, _Pred& __pred, _Proj1& __proj1, _Proj2& __proj2) {
159 return std::__search_forward_impl<_ClassicAlgPolicy>(__first1, __last1, __first2, __last2, __pred, __proj1, __proj2);
160}
161
162template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
163[[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator1
164search(_ForwardIterator1 __first1,
165 _ForwardIterator1 __last1,
166 _ForwardIterator2 __first2,
167 _ForwardIterator2 __last2,
168 _BinaryPredicate __pred) {
169 static_assert(__is_callable<_BinaryPredicate&, decltype(*__first1), decltype(*__first2)>::value,
170 "The comparator has to be callable");
171 auto __proj = __identity();
172 return std::__search_impl(__first1, __last1, __first2, __last2, __pred, __proj, __proj).first;
173}
174
175template <class _ForwardIterator1, class _ForwardIterator2>
176[[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator1
177search(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2) {
178 return std::search(__first1, __last1, __first2, __last2, __equal_to());
179}
180
181#if _LIBCPP_STD_VER >= 17
182template <class _ForwardIterator, class _Searcher>
183[[nodiscard]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
184search(_ForwardIterator __f, _ForwardIterator __l, const _Searcher& __s) {
185 return __s(__f, __l).first;
186}
187
188#endif
189
190_LIBCPP_END_NAMESPACE_STD
191
192#endif // _LIBCPP___ALGORITHM_SEARCH_H