v1/__algorithm/find_end.h

0001 // -*- C++ -*-
0002 //===----------------------------------------------------------------------===//
0003 //
0004 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0005 // See https://llvm.org/LICENSE.txt for license information.
0006 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0007 //
0008 //===----------------------------------------------------------------------===//
0009
0010 #ifndef _LIBCPP___ALGORITHM_FIND_END_OF_H
0011 #define _LIBCPP___ALGORITHM_FIND_END_OF_H
0012
0013 #include <__algorithm/comp.h>
0014 #include <__algorithm/iterator_operations.h>
0015 #include <__config>
0016 #include <__functional/identity.h>
0017 #include <__iterator/iterator_traits.h>
0018 #include <__type_traits/invoke.h>
0019 #include <__utility/pair.h>
0020
0021 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
0022 #  pragma GCC system_header
0023 #endif
0024
0025 _LIBCPP_BEGIN_NAMESPACE_STD
0026
0027 template < class _AlgPolicy,
0028            class _Iter1,
0029            class _Sent1,
0030            class _Iter2,
0031            class _Sent2,
0032            class _Pred,
0033            class _Proj1,
0034            class _Proj2>
0035 _LIBCPP_HIDE_FROM_ABI inline _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_Iter1, _Iter1> __find_end_impl(
0036     _Iter1 __first1,
0037     _Sent1 __last1,
0038     _Iter2 __first2,
0039     _Sent2 __last2,
0040     _Pred& __pred,
0041     _Proj1& __proj1,
0042     _Proj2& __proj2,
0043     forward_iterator_tag,
0044     forward_iterator_tag) {
0045   // modeled after search algorithm
0046   _Iter1 __match_first = _IterOps<_AlgPolicy>::next(__first1, __last1); // __last1 is the "default" answer
0047   _Iter1 __match_last  = __match_first;
0048   if (__first2 == __last2)
0049     return pair<_Iter1, _Iter1>(__match_last, __match_last);
0050   while (true) {
0051     while (true) {
0052       if (__first1 == __last1) // if source exhausted return last correct answer (or __last1 if never found)
0053         return pair<_Iter1, _Iter1>(__match_first, __match_last);
0054       if (std::__invoke(__pred, std::__invoke(__proj1, *__first1), std::__invoke(__proj2, *__first2)))
0055         break;
0056       ++__first1;
0057     }
0058     // *__first1 matches *__first2, now match elements after here
0059     _Iter1 __m1 = __first1;
0060     _Iter2 __m2 = __first2;
0061     while (true) {
0062       if (++__m2 == __last2) { // Pattern exhaused, record answer and search for another one
0063         __match_first = __first1;
0064         __match_last  = ++__m1;
0065         ++__first1;
0066         break;
0067       }
0068       if (++__m1 == __last1) // Source exhausted, return last answer
0069         return pair<_Iter1, _Iter1>(__match_first, __match_last);
0070       // mismatch, restart with a new __first
0071       if (!std::__invoke(__pred, std::__invoke(__proj1, *__m1), std::__invoke(__proj2, *__m2))) {
0072         ++__first1;
0073         break;
0074       } // else there is a match, check next elements
0075     }
0076   }
0077 }
0078
0079 template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
0080 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 _ForwardIterator1 __find_end_classic(
0081     _ForwardIterator1 __first1,
0082     _ForwardIterator1 __last1,
0083     _ForwardIterator2 __first2,
0084     _ForwardIterator2 __last2,
0085     _BinaryPredicate& __pred) {
0086   auto __proj = __identity();
0087   return std::__find_end_impl<_ClassicAlgPolicy>(
0088              __first1,
0089              __last1,
0090              __first2,
0091              __last2,
0092              __pred,
0093              __proj,
0094              __proj,
0095              typename iterator_traits<_ForwardIterator1>::iterator_category(),
0096              typename iterator_traits<_ForwardIterator2>::iterator_category())
0097       .first;
0098 }
0099
0100 template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
0101 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator1 find_end(
0102     _ForwardIterator1 __first1,
0103     _ForwardIterator1 __last1,
0104     _ForwardIterator2 __first2,
0105     _ForwardIterator2 __last2,
0106     _BinaryPredicate __pred) {
0107   return std::__find_end_classic(__first1, __last1, __first2, __last2, __pred);
0108 }
0109
0110 template <class _ForwardIterator1, class _ForwardIterator2>
0111 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator1
0112 find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2) {
0113   return std::find_end(__first1, __last1, __first2, __last2, __equal_to());
0114 }
0115
0116 _LIBCPP_END_NAMESPACE_STD
0117
0118 #endif // _LIBCPP___ALGORITHM_FIND_END_OF_H