1fe6060f1SDimitry Andric // -*- C++ -*- 2fe6060f1SDimitry Andric //===----------------------------------------------------------------------===// 3fe6060f1SDimitry Andric // 4fe6060f1SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5fe6060f1SDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 6fe6060f1SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7fe6060f1SDimitry Andric // 8fe6060f1SDimitry Andric //===----------------------------------------------------------------------===// 9fe6060f1SDimitry Andric 10fe6060f1SDimitry Andric #ifndef _LIBCPP___ALGORITHM_SEARCH_N_H 11fe6060f1SDimitry Andric #define _LIBCPP___ALGORITHM_SEARCH_N_H 12fe6060f1SDimitry Andric 13fe6060f1SDimitry Andric #include <__algorithm/comp.h> 14753f127fSDimitry Andric #include <__algorithm/iterator_operations.h> 1504eeddc0SDimitry Andric #include <__config> 16753f127fSDimitry Andric #include <__functional/identity.h> 1706c3fb27SDimitry Andric #include <__functional/invoke.h> 18753f127fSDimitry Andric #include <__iterator/advance.h> 19753f127fSDimitry Andric #include <__iterator/concepts.h> 20753f127fSDimitry Andric #include <__iterator/distance.h> 21fe6060f1SDimitry Andric #include <__iterator/iterator_traits.h> 22753f127fSDimitry Andric #include <__ranges/concepts.h> 2306c3fb27SDimitry Andric #include <__type_traits/is_callable.h> 24bdd1243dSDimitry Andric #include <__utility/convert_to_integral.h> 25753f127fSDimitry Andric #include <__utility/pair.h> 26fe6060f1SDimitry Andric 27fe6060f1SDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 28fe6060f1SDimitry Andric # pragma GCC system_header 29fe6060f1SDimitry Andric #endif 30fe6060f1SDimitry Andric 31fe6060f1SDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD 32fe6060f1SDimitry Andric 33753f127fSDimitry Andric template <class _AlgPolicy, class _Pred, class _Iter, class _Sent, class _SizeT, class _Type, class _Proj> 34cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_Iter, _Iter> __search_n_forward_impl( 35cb14a3feSDimitry Andric _Iter __first, _Sent __last, _SizeT __count, const _Type& __value, _Pred& __pred, _Proj& __proj) { 36fe6060f1SDimitry Andric if (__count <= 0) 37753f127fSDimitry Andric return std::make_pair(__first, __first); 38fe6060f1SDimitry Andric while (true) { 39753f127fSDimitry Andric // Find first element in sequence that matchs __value, with a mininum of loop checks 40fe6060f1SDimitry Andric while (true) { 41753f127fSDimitry Andric if (__first == __last) { // return __last if no element matches __value 42753f127fSDimitry Andric _IterOps<_AlgPolicy>::__advance_to(__first, __last); 43753f127fSDimitry Andric return std::make_pair(__first, __first); 44753f127fSDimitry Andric } 45753f127fSDimitry Andric if (std::__invoke(__pred, std::__invoke(__proj, *__first), __value)) 46fe6060f1SDimitry Andric break; 47fe6060f1SDimitry Andric ++__first; 48fe6060f1SDimitry Andric } 49753f127fSDimitry Andric // *__first matches __value, now match elements after here 50753f127fSDimitry Andric _Iter __m = __first; 51753f127fSDimitry Andric _SizeT __c(0); 52fe6060f1SDimitry Andric while (true) { 53fe6060f1SDimitry Andric if (++__c == __count) // If pattern exhausted, __first is the answer (works for 1 element pattern) 54753f127fSDimitry Andric return std::make_pair(__first, ++__m); 55753f127fSDimitry Andric if (++__m == __last) { // Otherwise if source exhaused, pattern not found 56753f127fSDimitry Andric _IterOps<_AlgPolicy>::__advance_to(__first, __last); 57753f127fSDimitry Andric return std::make_pair(__first, __first); 58753f127fSDimitry Andric } 59753f127fSDimitry Andric 60753f127fSDimitry Andric // if there is a mismatch, restart with a new __first 61cb14a3feSDimitry Andric if (!std::__invoke(__pred, std::__invoke(__proj, *__m), __value)) { 62fe6060f1SDimitry Andric __first = __m; 63fe6060f1SDimitry Andric ++__first; 64fe6060f1SDimitry Andric break; 65fe6060f1SDimitry Andric } // else there is a match, check next elements 66fe6060f1SDimitry Andric } 67fe6060f1SDimitry Andric } 68fe6060f1SDimitry Andric } 69fe6060f1SDimitry Andric 70753f127fSDimitry Andric template <class _AlgPolicy, class _Pred, class _Iter, class _Sent, class _SizeT, class _Type, class _Proj, class _DiffT> 71cb14a3feSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 std::pair<_Iter, _Iter> __search_n_random_access_impl( 72cb14a3feSDimitry Andric _Iter __first, _Sent __last, _SizeT __count, const _Type& __value, _Pred& __pred, _Proj& __proj, _DiffT __size1) { 73753f127fSDimitry Andric using difference_type = typename iterator_traits<_Iter>::difference_type; 74753f127fSDimitry Andric if (__count == 0) 75753f127fSDimitry Andric return std::make_pair(__first, __first); 76753f127fSDimitry Andric if (__size1 < static_cast<_DiffT>(__count)) { 77753f127fSDimitry Andric _IterOps<_AlgPolicy>::__advance_to(__first, __last); 78753f127fSDimitry Andric return std::make_pair(__first, __first); 79753f127fSDimitry Andric } 80753f127fSDimitry Andric 81753f127fSDimitry Andric const auto __s = __first + __size1 - difference_type(__count - 1); // Start of pattern match can't go beyond here 82fe6060f1SDimitry Andric while (true) { 83753f127fSDimitry Andric // Find first element in sequence that matchs __value, with a mininum of loop checks 84fe6060f1SDimitry Andric while (true) { 85753f127fSDimitry Andric if (__first >= __s) { // return __last if no element matches __value 86753f127fSDimitry Andric _IterOps<_AlgPolicy>::__advance_to(__first, __last); 87753f127fSDimitry Andric return std::make_pair(__first, __first); 88753f127fSDimitry Andric } 89753f127fSDimitry Andric if (std::__invoke(__pred, std::__invoke(__proj, *__first), __value)) 90fe6060f1SDimitry Andric break; 91fe6060f1SDimitry Andric ++__first; 92fe6060f1SDimitry Andric } 93fe6060f1SDimitry Andric // *__first matches __value_, now match elements after here 94753f127fSDimitry Andric auto __m = __first; 95753f127fSDimitry Andric _SizeT __c(0); 96fe6060f1SDimitry Andric while (true) { 97fe6060f1SDimitry Andric if (++__c == __count) // If pattern exhausted, __first is the answer (works for 1 element pattern) 98753f127fSDimitry Andric return std::make_pair(__first, __first + _DiffT(__count)); 99fe6060f1SDimitry Andric ++__m; // no need to check range on __m because __s guarantees we have enough source 100753f127fSDimitry Andric 101753f127fSDimitry Andric // if there is a mismatch, restart with a new __first 102cb14a3feSDimitry Andric if (!std::__invoke(__pred, std::__invoke(__proj, *__m), __value)) { 103fe6060f1SDimitry Andric __first = __m; 104fe6060f1SDimitry Andric ++__first; 105fe6060f1SDimitry Andric break; 106fe6060f1SDimitry Andric } // else there is a match, check next elements 107fe6060f1SDimitry Andric } 108fe6060f1SDimitry Andric } 109fe6060f1SDimitry Andric } 110fe6060f1SDimitry Andric 111*0fca6ea1SDimitry Andric template <class _Iter, 112*0fca6ea1SDimitry Andric class _Sent, 113*0fca6ea1SDimitry Andric class _DiffT, 114*0fca6ea1SDimitry Andric class _Type, 115*0fca6ea1SDimitry Andric class _Pred, 116*0fca6ea1SDimitry Andric class _Proj, 117*0fca6ea1SDimitry Andric __enable_if_t<__has_random_access_iterator_category<_Iter>::value, int> = 0> 118*0fca6ea1SDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_Iter, _Iter> 119*0fca6ea1SDimitry Andric __search_n_impl(_Iter __first, _Sent __last, _DiffT __count, const _Type& __value, _Pred& __pred, _Proj& __proj) { 120cb14a3feSDimitry Andric return std::__search_n_random_access_impl<_ClassicAlgPolicy>( 121cb14a3feSDimitry Andric __first, __last, __count, __value, __pred, __proj, __last - __first); 122753f127fSDimitry Andric } 123753f127fSDimitry Andric 124*0fca6ea1SDimitry Andric template <class _Iter1, 125*0fca6ea1SDimitry Andric class _Sent1, 126*0fca6ea1SDimitry Andric class _DiffT, 127*0fca6ea1SDimitry Andric class _Type, 128*0fca6ea1SDimitry Andric class _Pred, 129*0fca6ea1SDimitry Andric class _Proj, 130cb14a3feSDimitry Andric __enable_if_t<__has_forward_iterator_category<_Iter1>::value && 131*0fca6ea1SDimitry Andric !__has_random_access_iterator_category<_Iter1>::value, 132*0fca6ea1SDimitry Andric int> = 0> 133*0fca6ea1SDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_Iter1, _Iter1> 134*0fca6ea1SDimitry Andric __search_n_impl(_Iter1 __first, _Sent1 __last, _DiffT __count, const _Type& __value, _Pred& __pred, _Proj& __proj) { 135cb14a3feSDimitry Andric return std::__search_n_forward_impl<_ClassicAlgPolicy>(__first, __last, __count, __value, __pred, __proj); 136753f127fSDimitry Andric } 137753f127fSDimitry Andric 138fe6060f1SDimitry Andric template <class _ForwardIterator, class _Size, class _Tp, class _BinaryPredicate> 139*0fca6ea1SDimitry Andric _LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator search_n( 140cb14a3feSDimitry Andric _ForwardIterator __first, _ForwardIterator __last, _Size __count, const _Tp& __value, _BinaryPredicate __pred) { 141cb14a3feSDimitry Andric static_assert( 142cb14a3feSDimitry Andric __is_callable<_BinaryPredicate, decltype(*__first), const _Tp&>::value, "BinaryPredicate has to be callable"); 143753f127fSDimitry Andric auto __proj = __identity(); 144753f127fSDimitry Andric return std::__search_n_impl(__first, __last, std::__convert_to_integral(__count), __value, __pred, __proj).first; 145fe6060f1SDimitry Andric } 146fe6060f1SDimitry Andric 147fe6060f1SDimitry Andric template <class _ForwardIterator, class _Size, class _Tp> 148*0fca6ea1SDimitry Andric _LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator 149cb14a3feSDimitry Andric search_n(_ForwardIterator __first, _ForwardIterator __last, _Size __count, const _Tp& __value) { 150bdd1243dSDimitry Andric return std::search_n(__first, __last, std::__convert_to_integral(__count), __value, __equal_to()); 151fe6060f1SDimitry Andric } 152fe6060f1SDimitry Andric 153fe6060f1SDimitry Andric _LIBCPP_END_NAMESPACE_STD 154fe6060f1SDimitry Andric 155fe6060f1SDimitry Andric #endif // _LIBCPP___ALGORITHM_SEARCH_N_H 156