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/is_callable.h>
21 #include <__utility/pair.h>
22 #include <type_traits>
23
24 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
25 # pragma GCC system_header
26 #endif
27
28 _LIBCPP_BEGIN_NAMESPACE_STD
29
30 template <class _AlgPolicy,
31 class _Iter1, class _Sent1,
32 class _Iter2, class _Sent2,
33 class _Pred,
34 class _Proj1,
35 class _Proj2>
36 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
__search_forward_impl(_Iter1 __first1,_Sent1 __last1,_Iter2 __first2,_Sent2 __last2,_Pred & __pred,_Proj1 & __proj1,_Proj2 & __proj2)37 pair<_Iter1, _Iter1> __search_forward_impl(_Iter1 __first1, _Sent1 __last1,
38 _Iter2 __first2, _Sent2 __last2,
39 _Pred& __pred,
40 _Proj1& __proj1,
41 _Proj2& __proj2) {
42 if (__first2 == __last2)
43 return std::make_pair(__first1, __first1); // Everything matches an empty sequence
44 while (true) {
45 // Find first element in sequence 1 that matchs *__first2, with a mininum of loop checks
46 while (true) {
47 if (__first1 == __last1) { // return __last1 if no element matches *__first2
48 _IterOps<_AlgPolicy>::__advance_to(__first1, __last1);
49 return std::make_pair(__first1, __first1);
50 }
51 if (std::__invoke(__pred, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
52 break;
53 ++__first1;
54 }
55 // *__first1 matches *__first2, now match elements after here
56 _Iter1 __m1 = __first1;
57 _Iter2 __m2 = __first2;
58 while (true) {
59 if (++__m2 == __last2) // If pattern exhausted, __first1 is the answer (works for 1 element pattern)
60 return std::make_pair(__first1, ++__m1);
61 if (++__m1 == __last1) { // Otherwise if source exhaused, pattern not found
62 return std::make_pair(__m1, __m1);
63 }
64
65 // if there is a mismatch, restart with a new __first1
66 if (!std::__invoke(__pred, std::__invoke(__proj1, *__m1), std::__invoke(__proj2, *__m2)))
67 {
68 ++__first1;
69 break;
70 } // else there is a match, check next elements
71 }
72 }
73 }
74
75 template <class _AlgPolicy,
76 class _Iter1, class _Sent1,
77 class _Iter2, 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
__search_random_access_impl(_Iter1 __first1,_Sent1 __last1,_Iter2 __first2,_Sent2 __last2,_Pred & __pred,_Proj1 & __proj1,_Proj2 & __proj2,_DiffT1 __size1,_DiffT2 __size2)84 pair<_Iter1, _Iter1> __search_random_access_impl(_Iter1 __first1, _Sent1 __last1,
85 _Iter2 __first2, _Sent2 __last2,
86 _Pred& __pred,
87 _Proj1& __proj1,
88 _Proj2& __proj2,
89 _DiffT1 __size1,
90 _DiffT2 __size2) {
91 const _Iter1 __s = __first1 + __size1 - _DiffT1(__size2 - 1); // Start of pattern match can't go beyond here
92
93 while (true) {
94 while (true) {
95 if (__first1 == __s) {
96 _IterOps<_AlgPolicy>::__advance_to(__first1, __last1);
97 return std::make_pair(__first1, __first1);
98 }
99 if (std::__invoke(__pred, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
100 break;
101 ++__first1;
102 }
103
104 _Iter1 __m1 = __first1;
105 _Iter2 __m2 = __first2;
106 while (true) {
107 if (++__m2 == __last2)
108 return std::make_pair(__first1, __first1 + _DiffT1(__size2));
109 ++__m1; // no need to check range on __m1 because __s guarantees we have enough source
110 if (!std::__invoke(__pred, std::__invoke(__proj1, *__m1), std::__invoke(__proj2, *__m2))) {
111 ++__first1;
112 break;
113 }
114 }
115 }
116 }
117
118 template <class _Iter1, class _Sent1,
119 class _Iter2, class _Sent2,
120 class _Pred,
121 class _Proj1,
122 class _Proj2>
123 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
124 pair<_Iter1, _Iter1> __search_impl(_Iter1 __first1, _Sent1 __last1,
125 _Iter2 __first2, _Sent2 __last2,
126 _Pred& __pred,
127 _Proj1& __proj1,
128 _Proj2& __proj2,
129 __enable_if_t<__is_cpp17_random_access_iterator<_Iter1>::value
130 && __is_cpp17_random_access_iterator<_Iter2>::value>* = nullptr) {
131
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>(__first1, __last1,
142 __first2, __last2,
143 __pred,
144 __proj1,
145 __proj2,
146 __size1,
147 __size2);
148 }
149
150 template <class _Iter1, class _Sent1,
151 class _Iter2, class _Sent2,
152 class _Pred,
153 class _Proj1,
154 class _Proj2>
155 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
156 pair<_Iter1, _Iter1> __search_impl(_Iter1 __first1, _Sent1 __last1,
157 _Iter2 __first2, _Sent2 __last2,
158 _Pred& __pred,
159 _Proj1& __proj1,
160 _Proj2& __proj2,
161 __enable_if_t<__is_cpp17_forward_iterator<_Iter1>::value
162 && __is_cpp17_forward_iterator<_Iter2>::value
163 && !(__is_cpp17_random_access_iterator<_Iter1>::value
164 && __is_cpp17_random_access_iterator<_Iter2>::value)>* = nullptr) {
165 return std::__search_forward_impl<_ClassicAlgPolicy>(__first1, __last1,
166 __first2, __last2,
167 __pred,
168 __proj1,
169 __proj2);
170 }
171
172 template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
173 _LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
search(_ForwardIterator1 __first1,_ForwardIterator1 __last1,_ForwardIterator2 __first2,_ForwardIterator2 __last2,_BinaryPredicate __pred)174 _ForwardIterator1 search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
175 _ForwardIterator2 __first2, _ForwardIterator2 __last2,
176 _BinaryPredicate __pred) {
177 static_assert(__is_callable<_BinaryPredicate, decltype(*__first1), decltype(*__first2)>::value,
178 "BinaryPredicate has to be callable");
179 auto __proj = __identity();
180 return std::__search_impl(__first1, __last1, __first2, __last2, __pred, __proj, __proj).first;
181 }
182
183 template <class _ForwardIterator1, class _ForwardIterator2>
184 _LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
search(_ForwardIterator1 __first1,_ForwardIterator1 __last1,_ForwardIterator2 __first2,_ForwardIterator2 __last2)185 _ForwardIterator1 search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,
186 _ForwardIterator2 __first2, _ForwardIterator2 __last2) {
187 return std::search(__first1, __last1, __first2, __last2, __equal_to());
188 }
189
190 #if _LIBCPP_STD_VER > 14
191 template <class _ForwardIterator, class _Searcher>
192 _LIBCPP_NODISCARD_EXT _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
search(_ForwardIterator __f,_ForwardIterator __l,const _Searcher & __s)193 search(_ForwardIterator __f, _ForwardIterator __l, const _Searcher& __s) {
194 return __s(__f, __l).first;
195 }
196
197 #endif
198
199 _LIBCPP_END_NAMESPACE_STD
200
201 #endif // _LIBCPP___ALGORITHM_SEARCH_H
202