1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef _LIBCPP___ALGORITHM_RANGES_SEARCH_N_H 10 #define _LIBCPP___ALGORITHM_RANGES_SEARCH_N_H 11 12 #include <__algorithm/iterator_operations.h> 13 #include <__algorithm/search_n.h> 14 #include <__config> 15 #include <__functional/identity.h> 16 #include <__functional/ranges_operations.h> 17 #include <__iterator/advance.h> 18 #include <__iterator/concepts.h> 19 #include <__iterator/distance.h> 20 #include <__iterator/incrementable_traits.h> 21 #include <__iterator/indirectly_comparable.h> 22 #include <__iterator/iterator_traits.h> 23 #include <__ranges/access.h> 24 #include <__ranges/concepts.h> 25 #include <__ranges/size.h> 26 #include <__ranges/subrange.h> 27 #include <__utility/move.h> 28 #include <__utility/pair.h> 29 30 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 31 # pragma GCC system_header 32 #endif 33 34 _LIBCPP_PUSH_MACROS 35 #include <__undef_macros> 36 37 #if _LIBCPP_STD_VER >= 20 38 39 _LIBCPP_BEGIN_NAMESPACE_STD 40 41 namespace ranges { 42 namespace __search_n { 43 struct __fn { 44 template <class _Iter1, class _Sent1, class _SizeT, class _Type, class _Pred, class _Proj> __ranges_search_n_impl__fn45 _LIBCPP_HIDE_FROM_ABI static constexpr subrange<_Iter1> __ranges_search_n_impl( 46 _Iter1 __first, _Sent1 __last, _SizeT __count, const _Type& __value, _Pred& __pred, _Proj& __proj) { 47 if (__count == 0) 48 return {__first, __first}; 49 50 if constexpr (sized_sentinel_for<_Sent1, _Iter1>) { 51 auto __size = ranges::distance(__first, __last); 52 if (__size < __count) { 53 ranges::advance(__first, __last); 54 return {__first, __first}; 55 } 56 57 if constexpr (random_access_iterator<_Iter1>) { 58 auto __ret = std::__search_n_random_access_impl<_RangeAlgPolicy>( 59 __first, __last, __count, __value, __pred, __proj, __size); 60 return {std::move(__ret.first), std::move(__ret.second)}; 61 } 62 } 63 64 auto __ret = std::__search_n_forward_impl<_RangeAlgPolicy>(__first, __last, __count, __value, __pred, __proj); 65 return {std::move(__ret.first), std::move(__ret.second)}; 66 } 67 68 template <forward_iterator _Iter, 69 sentinel_for<_Iter> _Sent, 70 class _Type, 71 class _Pred = ranges::equal_to, 72 class _Proj = identity> 73 requires indirectly_comparable<_Iter, const _Type*, _Pred, _Proj> 74 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr subrange<_Iter> operator__fn75 operator()(_Iter __first, 76 _Sent __last, 77 iter_difference_t<_Iter> __count, 78 const _Type& __value, 79 _Pred __pred = {}, 80 _Proj __proj = _Proj{}) const { 81 return __ranges_search_n_impl(__first, __last, __count, __value, __pred, __proj); 82 } 83 84 template <forward_range _Range, class _Type, class _Pred = ranges::equal_to, class _Proj = identity> 85 requires indirectly_comparable<iterator_t<_Range>, const _Type*, _Pred, _Proj> operator__fn86 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr borrowed_subrange_t<_Range> operator()( 87 _Range&& __range, range_difference_t<_Range> __count, const _Type& __value, _Pred __pred = {}, _Proj __proj = {}) 88 const { 89 auto __first = ranges::begin(__range); 90 if (__count <= 0) 91 return {__first, __first}; 92 if constexpr (sized_range<_Range>) { 93 auto __size1 = ranges::size(__range); 94 if (__size1 < static_cast<range_size_t<_Range>>(__count)) { 95 ranges::advance(__first, ranges::end(__range)); 96 return {__first, __first}; 97 } 98 } 99 100 return __ranges_search_n_impl(ranges::begin(__range), ranges::end(__range), __count, __value, __pred, __proj); 101 } 102 }; 103 } // namespace __search_n 104 105 inline namespace __cpo { 106 inline constexpr auto search_n = __search_n::__fn{}; 107 } // namespace __cpo 108 } // namespace ranges 109 110 _LIBCPP_END_NAMESPACE_STD 111 112 #endif // _LIBCPP_STD_VER >= 20 113 114 _LIBCPP_POP_MACROS 115 116 #endif // _LIBCPP___ALGORITHM_RANGES_SEARCH_N_H 117