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_PARTIAL_SORT_H 10 #define _LIBCPP___ALGORITHM_PARTIAL_SORT_H 11 12 #include <__algorithm/comp.h> 13 #include <__algorithm/comp_ref_type.h> 14 #include <__algorithm/make_heap.h> 15 #include <__algorithm/sift_down.h> 16 #include <__algorithm/sort_heap.h> 17 #include <__config> 18 #include <__debug> 19 #include <__debug_utils/randomize_range.h> 20 #include <__iterator/iterator_traits.h> 21 #include <__utility/swap.h> 22 23 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 24 # pragma GCC system_header 25 #endif 26 27 _LIBCPP_BEGIN_NAMESPACE_STD 28 29 template <class _Compare, class _RandomAccessIterator> 30 _LIBCPP_CONSTEXPR_AFTER_CXX17 void 31 __partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last, 32 _Compare __comp) 33 { 34 if (__first == __middle) 35 return; 36 _VSTD::__make_heap<_Compare>(__first, __middle, __comp); 37 typename iterator_traits<_RandomAccessIterator>::difference_type __len = __middle - __first; 38 for (_RandomAccessIterator __i = __middle; __i != __last; ++__i) 39 { 40 if (__comp(*__i, *__first)) 41 { 42 swap(*__i, *__first); 43 _VSTD::__sift_down<_Compare>(__first, __comp, __len, __first); 44 } 45 } 46 _VSTD::__sort_heap<_Compare>(__first, __middle, __comp); 47 } 48 49 template <class _RandomAccessIterator, class _Compare> 50 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 51 void 52 partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last, 53 _Compare __comp) 54 { 55 std::__debug_randomize_range(__first, __last); 56 typedef typename __comp_ref_type<_Compare>::type _Comp_ref; 57 _VSTD::__partial_sort<_Comp_ref>(__first, __middle, __last, __comp); 58 std::__debug_randomize_range(__middle, __last); 59 } 60 61 template <class _RandomAccessIterator> 62 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 63 void 64 partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last) 65 { 66 _VSTD::partial_sort(__first, __middle, __last, 67 __less<typename iterator_traits<_RandomAccessIterator>::value_type>()); 68 } 69 70 _LIBCPP_END_NAMESPACE_STD 71 72 #endif // _LIBCPP___ALGORITHM_PARTIAL_SORT_H 73