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_PUSH_MACROS
32#include <__undef_macros>
33
34_LIBCPP_BEGIN_NAMESPACE_STD
35
36template <class _AlgPolicy,
37          class _Compare,
38          class _InputIterator,
39          class _Sentinel1,
40          class _RandomAccessIterator,
41          class _Sentinel2,
42          class _Proj1,
43          class _Proj2>
44_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 pair<_InputIterator, _RandomAccessIterator> __partial_sort_copy(
45    _InputIterator __first,
46    _Sentinel1 __last,
47    _RandomAccessIterator __result_first,
48    _Sentinel2 __result_last,
49    _Compare&& __comp,
50    _Proj1&& __proj1,
51    _Proj2&& __proj2) {
52  _RandomAccessIterator __r = __result_first;
53  auto&& __projected_comp   = std::__make_projected(__comp, __proj2);
54
55  if (__r != __result_last) {
56    for (; __first != __last && __r != __result_last; ++__first, (void)++__r)
57      *__r = *__first;
58    std::__make_heap<_AlgPolicy>(__result_first, __r, __projected_comp);
59    typename iterator_traits<_RandomAccessIterator>::difference_type __len = __r - __result_first;
60    for (; __first != __last; ++__first)
61      if (std::__invoke(__comp, std::__invoke(__proj1, *__first), std::__invoke(__proj2, *__result_first))) {
62        *__result_first = *__first;
63        std::__sift_down<_AlgPolicy>(__result_first, __projected_comp, __len, __result_first);
64      }
65    std::__sort_heap<_AlgPolicy>(__result_first, __r, __projected_comp);
66  }
67
68  return pair<_InputIterator, _RandomAccessIterator>(
69      _IterOps<_AlgPolicy>::next(std::move(__first), std::move(__last)), std::move(__r));
70}
71
72template <class _InputIterator, class _RandomAccessIterator, class _Compare>
73inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _RandomAccessIterator partial_sort_copy(
74    _InputIterator __first,
75    _InputIterator __last,
76    _RandomAccessIterator __result_first,
77    _RandomAccessIterator __result_last,
78    _Compare __comp) {
79  static_assert(
80      __is_callable<_Compare, decltype(*__first), decltype(*__result_first)>::value, "Comparator has to be callable");
81
82  auto __result = std::__partial_sort_copy<_ClassicAlgPolicy>(
83      __first,
84      __last,
85      __result_first,
86      __result_last,
87      static_cast<__comp_ref_type<_Compare> >(__comp),
88      __identity(),
89      __identity());
90  return __result.second;
91}
92
93template <class _InputIterator, class _RandomAccessIterator>
94inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _RandomAccessIterator partial_sort_copy(
95    _InputIterator __first,
96    _InputIterator __last,
97    _RandomAccessIterator __result_first,
98    _RandomAccessIterator __result_last) {
99  return std::partial_sort_copy(__first, __last, __result_first, __result_last, __less<>());
100}
101
102_LIBCPP_END_NAMESPACE_STD
103
104_LIBCPP_POP_MACROS
105
106#endif // _LIBCPP___ALGORITHM_PARTIAL_SORT_COPY_H
107