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 <__config> 13 #include <__algorithm/comp.h> 14 #include <__algorithm/comp_ref_type.h> 15 #include <__algorithm/make_heap.h> 16 #include <__algorithm/sift_down.h> 17 #include <__algorithm/sort_heap.h> 18 #include <__iterator/iterator_traits.h> 19 #include <__utility/swap.h> 20 21 #if defined(_LIBCPP_DEBUG_RANDOMIZE_UNSPECIFIED_STABILITY) 22 # include <__algorithm/shuffle.h> 23 #endif 24 25 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 26 #pragma GCC system_header 27 #endif 28 29 _LIBCPP_BEGIN_NAMESPACE_STD 30 31 template <class _Compare, class _RandomAccessIterator> 32 _LIBCPP_CONSTEXPR_AFTER_CXX17 void 33 __partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last, 34 _Compare __comp) 35 { 36 if (__first == __middle) 37 return; 38 _VSTD::__make_heap<_Compare>(__first, __middle, __comp); 39 typename iterator_traits<_RandomAccessIterator>::difference_type __len = __middle - __first; 40 for (_RandomAccessIterator __i = __middle; __i != __last; ++__i) 41 { 42 if (__comp(*__i, *__first)) 43 { 44 swap(*__i, *__first); 45 _VSTD::__sift_down<_Compare>(__first, __comp, __len, __first); 46 } 47 } 48 _VSTD::__sort_heap<_Compare>(__first, __middle, __comp); 49 } 50 51 template <class _RandomAccessIterator, class _Compare> 52 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 53 void 54 partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last, 55 _Compare __comp) 56 { 57 _LIBCPP_DEBUG_RANDOMIZE_RANGE(__first, __last); 58 typedef typename __comp_ref_type<_Compare>::type _Comp_ref; 59 _VSTD::__partial_sort<_Comp_ref>(__first, __middle, __last, __comp); 60 _LIBCPP_DEBUG_RANDOMIZE_RANGE(__middle, __last); 61 } 62 63 template <class _RandomAccessIterator> 64 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 65 void 66 partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last) 67 { 68 _VSTD::partial_sort(__first, __middle, __last, 69 __less<typename iterator_traits<_RandomAccessIterator>::value_type>()); 70 } 71 72 _LIBCPP_END_NAMESPACE_STD 73 74 #endif // _LIBCPP___ALGORITHM_PARTIAL_SORT_H 75