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_COPY_H
10 #define _LIBCPP___ALGORITHM_PARTIAL_SORT_COPY_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 <type_traits> // swap
20 
21 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
22 #pragma GCC system_header
23 #endif
24 
25 _LIBCPP_PUSH_MACROS
26 #include <__undef_macros>
27 
28 _LIBCPP_BEGIN_NAMESPACE_STD
29 
30 template <class _Compare, class _InputIterator, class _RandomAccessIterator>
31 _LIBCPP_CONSTEXPR_AFTER_CXX17 _RandomAccessIterator
32 __partial_sort_copy(_InputIterator __first, _InputIterator __last,
33                     _RandomAccessIterator __result_first, _RandomAccessIterator __result_last, _Compare __comp)
34 {
35     _RandomAccessIterator __r = __result_first;
36     if (__r != __result_last)
37     {
38         for (; __first != __last && __r != __result_last; ++__first, (void) ++__r)
39             *__r = *__first;
40         _VSTD::__make_heap<_Compare>(__result_first, __r, __comp);
41         typename iterator_traits<_RandomAccessIterator>::difference_type __len = __r - __result_first;
42         for (; __first != __last; ++__first)
43             if (__comp(*__first, *__result_first))
44             {
45                 *__result_first = *__first;
46                 _VSTD::__sift_down<_Compare>(__result_first, __r, __comp, __len, __result_first);
47             }
48         _VSTD::__sort_heap<_Compare>(__result_first, __r, __comp);
49     }
50     return __r;
51 }
52 
53 template <class _InputIterator, class _RandomAccessIterator, class _Compare>
54 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
55 _RandomAccessIterator
56 partial_sort_copy(_InputIterator __first, _InputIterator __last,
57                   _RandomAccessIterator __result_first, _RandomAccessIterator __result_last, _Compare __comp)
58 {
59     typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
60     return _VSTD::__partial_sort_copy<_Comp_ref>(__first, __last, __result_first, __result_last, __comp);
61 }
62 
63 template <class _InputIterator, class _RandomAccessIterator>
64 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
65 _RandomAccessIterator
66 partial_sort_copy(_InputIterator __first, _InputIterator __last,
67                   _RandomAccessIterator __result_first, _RandomAccessIterator __result_last)
68 {
69     return _VSTD::partial_sort_copy(__first, __last, __result_first, __result_last,
70                                    __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
71 }
72 
73 _LIBCPP_END_NAMESPACE_STD
74 
75 _LIBCPP_POP_MACROS
76 
77 #endif // _LIBCPP___ALGORITHM_PARTIAL_SORT_COPY_H
78