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 <__config> 15 #include <__iterator/iterator_traits.h> 16 #include <utility> 17 18 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 19 #pragma GCC system_header 20 #endif 21 22 _LIBCPP_PUSH_MACROS 23 #include <__undef_macros> 24 25 _LIBCPP_BEGIN_NAMESPACE_STD 26 27 template <class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2> 28 pair<_ForwardIterator1, _ForwardIterator1> 29 _LIBCPP_CONSTEXPR_AFTER_CXX11 __search(_ForwardIterator1 __first1, _ForwardIterator1 __last1, 30 _ForwardIterator2 __first2, _ForwardIterator2 __last2, 31 _BinaryPredicate __pred, forward_iterator_tag, forward_iterator_tag) { 32 if (__first2 == __last2) 33 return _VSTD::make_pair(__first1, __first1); // Everything matches an empty sequence 34 while (true) { 35 // Find first element in sequence 1 that matchs *__first2, with a mininum of loop checks 36 while (true) { 37 if (__first1 == __last1) // return __last1 if no element matches *__first2 38 return _VSTD::make_pair(__last1, __last1); 39 if (__pred(*__first1, *__first2)) 40 break; 41 ++__first1; 42 } 43 // *__first1 matches *__first2, now match elements after here 44 _ForwardIterator1 __m1 = __first1; 45 _ForwardIterator2 __m2 = __first2; 46 while (true) { 47 if (++__m2 == __last2) // If pattern exhausted, __first1 is the answer (works for 1 element pattern) 48 return _VSTD::make_pair(__first1, __m1); 49 if (++__m1 == __last1) // Otherwise if source exhaused, pattern not found 50 return _VSTD::make_pair(__last1, __last1); 51 if (!__pred(*__m1, *__m2)) // if there is a mismatch, restart with a new __first1 52 { 53 ++__first1; 54 break; 55 } // else there is a match, check next elements 56 } 57 } 58 } 59 60 template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2> 61 _LIBCPP_CONSTEXPR_AFTER_CXX11 pair<_RandomAccessIterator1, _RandomAccessIterator1> 62 __search(_RandomAccessIterator1 __first1, _RandomAccessIterator1 __last1, _RandomAccessIterator2 __first2, 63 _RandomAccessIterator2 __last2, _BinaryPredicate __pred, random_access_iterator_tag, 64 random_access_iterator_tag) { 65 typedef typename iterator_traits<_RandomAccessIterator1>::difference_type _D1; 66 typedef typename iterator_traits<_RandomAccessIterator2>::difference_type _D2; 67 // Take advantage of knowing source and pattern lengths. Stop short when source is smaller than pattern 68 const _D2 __len2 = __last2 - __first2; 69 if (__len2 == 0) 70 return _VSTD::make_pair(__first1, __first1); 71 const _D1 __len1 = __last1 - __first1; 72 if (__len1 < __len2) 73 return _VSTD::make_pair(__last1, __last1); 74 const _RandomAccessIterator1 __s = __last1 - (__len2 - 1); // Start of pattern match can't go beyond here 75 76 while (true) { 77 while (true) { 78 if (__first1 == __s) 79 return _VSTD::make_pair(__last1, __last1); 80 if (__pred(*__first1, *__first2)) 81 break; 82 ++__first1; 83 } 84 85 _RandomAccessIterator1 __m1 = __first1; 86 _RandomAccessIterator2 __m2 = __first2; 87 while (true) { 88 if (++__m2 == __last2) 89 return _VSTD::make_pair(__first1, __first1 + __len2); 90 ++__m1; // no need to check range on __m1 because __s guarantees we have enough source 91 if (!__pred(*__m1, *__m2)) { 92 ++__first1; 93 break; 94 } 95 } 96 } 97 } 98 99 template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate> 100 _LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator1 101 search(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2, 102 _BinaryPredicate __pred) { 103 return _VSTD::__search<_BinaryPredicate&>( 104 __first1, __last1, __first2, __last2, __pred, 105 typename iterator_traits<_ForwardIterator1>::iterator_category(), 106 typename iterator_traits<_ForwardIterator2>::iterator_category()).first; 107 } 108 109 template <class _ForwardIterator1, class _ForwardIterator2> 110 _LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator1 111 search(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2, _ForwardIterator2 __last2) { 112 typedef typename iterator_traits<_ForwardIterator1>::value_type __v1; 113 typedef typename iterator_traits<_ForwardIterator2>::value_type __v2; 114 return _VSTD::search(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>()); 115 } 116 117 #if _LIBCPP_STD_VER > 14 118 template <class _ForwardIterator, class _Searcher> 119 _LIBCPP_NODISCARD_EXT _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator 120 search(_ForwardIterator __f, _ForwardIterator __l, const _Searcher& __s) { 121 return __s(__f, __l).first; 122 } 123 124 #endif 125 126 _LIBCPP_END_NAMESPACE_STD 127 128 _LIBCPP_POP_MACROS 129 130 #endif // _LIBCPP___ALGORITHM_SEARCH_H 131