libcxx/include/__algorithm/find_end.h

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