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 <__algorithm/comp.h>
13#include <__algorithm/comp_ref_type.h>
14#include <__algorithm/iterator_operations.h>
15#include <__algorithm/make_heap.h>
16#include <__algorithm/make_projected.h>
17#include <__algorithm/sift_down.h>
18#include <__algorithm/sort_heap.h>
19#include <__config>
20#include <__functional/identity.h>
21#include <__functional/invoke.h>
22#include <__iterator/iterator_traits.h>
23#include <__type_traits/is_callable.h>
24#include <__utility/move.h>
25#include <__utility/pair.h>
26
27#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
28#  pragma GCC system_header
29#endif
30
31_LIBCPP_BEGIN_NAMESPACE_STD
32
33template <class _AlgPolicy, class _Compare,
34          class _InputIterator, class _Sentinel1, class _RandomAccessIterator, class _Sentinel2,
35          class _Proj1, class _Proj2>
36_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_InputIterator, _RandomAccessIterator>
37__partial_sort_copy(_InputIterator __first, _Sentinel1 __last,
38                    _RandomAccessIterator __result_first, _Sentinel2 __result_last,
39                    _Compare&& __comp, _Proj1&& __proj1, _Proj2&& __proj2)
40{
41    _RandomAccessIterator __r = __result_first;
42    auto&& __projected_comp = std::__make_projected(__comp, __proj2);
43
44    if (__r != __result_last)
45    {
46        for (; __first != __last && __r != __result_last; ++__first, (void) ++__r)
47            *__r = *__first;
48        std::__make_heap<_AlgPolicy>(__result_first, __r, __projected_comp);
49        typename iterator_traits<_RandomAccessIterator>::difference_type __len = __r - __result_first;
50        for (; __first != __last; ++__first)
51            if (std::__invoke(__comp, std::__invoke(__proj1, *__first), std::__invoke(__proj2, *__result_first))) {
52                *__result_first = *__first;
53                std::__sift_down<_AlgPolicy>(__result_first, __projected_comp, __len, __result_first);
54            }
55        std::__sort_heap<_AlgPolicy>(__result_first, __r, __projected_comp);
56    }
57
58    return pair<_InputIterator, _RandomAccessIterator>(
59        _IterOps<_AlgPolicy>::next(std::move(__first), std::move(__last)), std::move(__r));
60}
61
62template <class _InputIterator, class _RandomAccessIterator, class _Compare>
63inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
64_RandomAccessIterator
65partial_sort_copy(_InputIterator __first, _InputIterator __last,
66                  _RandomAccessIterator __result_first, _RandomAccessIterator __result_last, _Compare __comp)
67{
68  static_assert(__is_callable<_Compare, decltype(*__first), decltype(*__result_first)>::value,
69                "Comparator has to be callable");
70
71  auto __result = std::__partial_sort_copy<_ClassicAlgPolicy>(__first, __last, __result_first, __result_last,
72      static_cast<__comp_ref_type<_Compare> >(__comp), __identity(), __identity());
73  return __result.second;
74}
75
76template <class _InputIterator, class _RandomAccessIterator>
77inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
78_RandomAccessIterator
79partial_sort_copy(_InputIterator __first, _InputIterator __last,
80                  _RandomAccessIterator __result_first, _RandomAccessIterator __result_last)
81{
82    return _VSTD::partial_sort_copy(__first, __last, __result_first, __result_last,
83                                   __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
84}
85
86_LIBCPP_END_NAMESPACE_STD
87
88#endif // _LIBCPP___ALGORITHM_PARTIAL_SORT_COPY_H
89