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 <__algorithm/search.h> 16 #include <__config> 17 #include <__functional/identity.h> 18 #include <__functional/invoke.h> 19 #include <__iterator/advance.h> 20 #include <__iterator/iterator_traits.h> 21 #include <__iterator/next.h> 22 #include <__iterator/reverse_iterator.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 31 template < 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 inline _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_Iter1, _Iter1> __find_end_impl( 40 _Iter1 __first1, 41 _Sent1 __last1, 42 _Iter2 __first2, 43 _Sent2 __last2, 44 _Pred& __pred, 45 _Proj1& __proj1, 46 _Proj2& __proj2, 47 forward_iterator_tag, 48 forward_iterator_tag) { 49 // modeled after search algorithm 50 _Iter1 __match_first = _IterOps<_AlgPolicy>::next(__first1, __last1); // __last1 is the "default" answer 51 _Iter1 __match_last = __match_first; 52 if (__first2 == __last2) 53 return pair<_Iter1, _Iter1>(__match_last, __match_last); 54 while (true) { 55 while (true) { 56 if (__first1 == __last1) // if source exhausted return last correct answer (or __last1 if never found) 57 return pair<_Iter1, _Iter1>(__match_first, __match_last); 58 if (std::__invoke(__pred, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2))) 59 break; 60 ++__first1; 61 } 62 // *__first1 matches *__first2, now match elements after here 63 _Iter1 __m1 = __first1; 64 _Iter2 __m2 = __first2; 65 while (true) { 66 if (++__m2 == __last2) { // Pattern exhaused, record answer and search for another one 67 __match_first = __first1; 68 __match_last = ++__m1; 69 ++__first1; 70 break; 71 } 72 if (++__m1 == __last1) // Source exhausted, return last answer 73 return pair<_Iter1, _Iter1>(__match_first, __match_last); 74 // mismatch, restart with a new __first 75 if (!std::__invoke(__pred, std::__invoke(__proj1, *__m1), std::__invoke(__proj2, *__m2))) { 76 ++__first1; 77 break; 78 } // else there is a match, check next elements 79 } 80 } 81 } 82 83 template < class _IterOps, 84 class _Pred, 85 class _Iter1, 86 class _Sent1, 87 class _Iter2, 88 class _Sent2, 89 class _Proj1, 90 class _Proj2> 91 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Iter1 __find_end( 92 _Iter1 __first1, 93 _Sent1 __sent1, 94 _Iter2 __first2, 95 _Sent2 __sent2, 96 _Pred& __pred, 97 _Proj1& __proj1, 98 _Proj2& __proj2, 99 bidirectional_iterator_tag, 100 bidirectional_iterator_tag) { 101 auto __last1 = _IterOps::next(__first1, __sent1); 102 auto __last2 = _IterOps::next(__first2, __sent2); 103 // modeled after search algorithm (in reverse) 104 if (__first2 == __last2) 105 return __last1; // Everything matches an empty sequence 106 _Iter1 __l1 = __last1; 107 _Iter2 __l2 = __last2; 108 --__l2; 109 while (true) { 110 // Find last element in sequence 1 that matchs *(__last2-1), with a mininum of loop checks 111 while (true) { 112 if (__first1 == __l1) // return __last1 if no element matches *__first2 113 return __last1; 114 if (std::__invoke(__pred, std::__invoke(__proj1, *--__l1), std::__invoke(__proj2, *__l2))) 115 break; 116 } 117 // *__l1 matches *__l2, now match elements before here 118 _Iter1 __m1 = __l1; 119 _Iter2 __m2 = __l2; 120 while (true) { 121 if (__m2 == __first2) // If pattern exhausted, __m1 is the answer (works for 1 element pattern) 122 return __m1; 123 if (__m1 == __first1) // Otherwise if source exhaused, pattern not found 124 return __last1; 125 126 // if there is a mismatch, restart with a new __l1 127 if (!std::__invoke(__pred, std::__invoke(__proj1, *--__m1), std::__invoke(__proj2, *--__m2))) { 128 break; 129 } // else there is a match, check next elements 130 } 131 } 132 } 133 134 template < class _AlgPolicy, 135 class _Pred, 136 class _Iter1, 137 class _Sent1, 138 class _Iter2, 139 class _Sent2, 140 class _Proj1, 141 class _Proj2> 142 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _Iter1 __find_end( 143 _Iter1 __first1, 144 _Sent1 __sent1, 145 _Iter2 __first2, 146 _Sent2 __sent2, 147 _Pred& __pred, 148 _Proj1& __proj1, 149 _Proj2& __proj2, 150 random_access_iterator_tag, 151 random_access_iterator_tag) { 152 typedef typename iterator_traits<_Iter1>::difference_type _D1; 153 auto __last1 = _IterOps<_AlgPolicy>::next(__first1, __sent1); 154 auto __last2 = _IterOps<_AlgPolicy>::next(__first2, __sent2); 155 // Take advantage of knowing source and pattern lengths. Stop short when source is smaller than pattern 156 auto __len2 = __last2 - __first2; 157 if (__len2 == 0) 158 return __last1; 159 auto __len1 = __last1 - __first1; 160 if (__len1 < __len2) 161 return __last1; 162 const _Iter1 __s = __first1 + _D1(__len2 - 1); // End of pattern match can't go before here 163 _Iter1 __l1 = __last1; 164 _Iter2 __l2 = __last2; 165 --__l2; 166 while (true) { 167 while (true) { 168 if (__s == __l1) 169 return __last1; 170 if (std::__invoke(__pred, std::__invoke(__proj1, *--__l1), std::__invoke(__proj2, *__l2))) 171 break; 172 } 173 _Iter1 __m1 = __l1; 174 _Iter2 __m2 = __l2; 175 while (true) { 176 if (__m2 == __first2) 177 return __m1; 178 // no need to check range on __m1 because __s guarantees we have enough source 179 if (!std::__invoke(__pred, std::__invoke(__proj1, *--__m1), std::__invoke(*--__m2))) { 180 break; 181 } 182 } 183 } 184 } 185 186 template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate> 187 _LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator1 __find_end_classic( 188 _ForwardIterator1 __first1, 189 _ForwardIterator1 __last1, 190 _ForwardIterator2 __first2, 191 _ForwardIterator2 __last2, 192 _BinaryPredicate& __pred) { 193 auto __proj = __identity(); 194 return std::__find_end_impl<_ClassicAlgPolicy>( 195 __first1, 196 __last1, 197 __first2, 198 __last2, 199 __pred, 200 __proj, 201 __proj, 202 typename iterator_traits<_ForwardIterator1>::iterator_category(), 203 typename iterator_traits<_ForwardIterator2>::iterator_category()) 204 .first; 205 } 206 207 template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate> 208 _LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator1 find_end( 209 _ForwardIterator1 __first1, 210 _ForwardIterator1 __last1, 211 _ForwardIterator2 __first2, 212 _ForwardIterator2 __last2, 213 _BinaryPredicate __pred) { 214 return std::__find_end_classic(__first1, __last1, __first2, __last2, __pred); 215 } 216 217 template <class _ForwardIterator1, class _ForwardIterator2> 218 _LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator1 219 find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2) { 220 return std::find_end(__first1, __last1, __first2, __last2, __equal_to()); 221 } 222 223 _LIBCPP_END_NAMESPACE_STD 224 225 #endif // _LIBCPP___ALGORITHM_FIND_END_OF_H 226