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_MAKE_HEAP_H
10#define _LIBCPP___ALGORITHM_MAKE_HEAP_H
11
12#include <__algorithm/comp.h>
13#include <__algorithm/comp_ref_type.h>
14#include <__algorithm/iterator_operations.h>
15#include <__algorithm/push_heap.h>
16#include <__algorithm/sift_down.h>
17#include <__config>
18#include <__iterator/iterator_traits.h>
19#include <__type_traits/is_arithmetic.h>
20#include <__utility/move.h>
21
22#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
23# pragma GCC system_header
24#endif
25
26_LIBCPP_PUSH_MACROS
27#include <__undef_macros>
28
29_LIBCPP_BEGIN_NAMESPACE_STD
30
31template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
32inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
33__make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare&& __comp) {
34 __comp_ref_type<_Compare> __comp_ref = __comp;
35
36 using __diff_t = __iterator_difference_type<_RandomAccessIterator>;
37 const __diff_t __n = __last - __first;
38
39 const bool __assume_both_children = is_arithmetic<__iterator_value_type<_RandomAccessIterator> >::value;
40
41 // While it would be correct to always assume we have both children, in practice we observed this to be a performance
42 // improvement only for arithmetic types.
43 const __diff_t __sift_down_n = __assume_both_children ? ((__n & 1) ? __n : __n - 1) : __n;
44
45 if (__n > 1) {
46 // start from the first parent, there is no need to consider children
47
48 for (__diff_t __start = (__sift_down_n - 2) / 2; __start >= 0; --__start) {
49 std::__sift_down<_AlgPolicy, __assume_both_children>(__first, __comp_ref, __sift_down_n, __start);
50 }
51 if _LIBCPP_CONSTEXPR (__assume_both_children)
52 std::__sift_up<_AlgPolicy>(__first, __last, __comp, __n);
53 }
54}
55
56template <class _RandomAccessIterator, class _Compare>
57inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
58make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
59 std::__make_heap<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __comp);
60}
61
62template <class _RandomAccessIterator>
63inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
64make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last) {
65 std::make_heap(std::move(__first), std::move(__last), __less<>());
66}
67
68_LIBCPP_END_NAMESPACE_STD
69
70_LIBCPP_POP_MACROS
71
72#endif // _LIBCPP___ALGORITHM_MAKE_HEAP_H
73