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/sift_down.h>
15 #include <__config>
16 #include <__iterator/iterator_traits.h>
17 
18 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
19 #  pragma GCC system_header
20 #  pragma clang include_instead(<algorithm>)
21 #endif
22 
23 _LIBCPP_BEGIN_NAMESPACE_STD
24 
25 template <class _Compare, class _RandomAccessIterator>
26 _LIBCPP_CONSTEXPR_AFTER_CXX11 void
27 __make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
28 {
29     typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
30     difference_type __n = __last - __first;
31     if (__n > 1)
32     {
33         // start from the first parent, there is no need to consider children
34         for (difference_type __start = (__n - 2) / 2; __start >= 0; --__start)
35         {
36             _VSTD::__sift_down<_Compare>(__first, __comp, __n, __first + __start);
37         }
38     }
39 }
40 
41 template <class _RandomAccessIterator, class _Compare>
42 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
43 void
44 make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
45 {
46     typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
47     _VSTD::__make_heap<_Comp_ref>(__first, __last, __comp);
48 }
49 
50 template <class _RandomAccessIterator>
51 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
52 void
53 make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
54 {
55     _VSTD::make_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
56 }
57 
58 _LIBCPP_END_NAMESPACE_STD
59 
60 #endif // _LIBCPP___ALGORITHM_MAKE_HEAP_H
61