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 <__config>
13 #include <__algorithm/comp.h>
14 #include <__algorithm/comp_ref_type.h>
15 #include <__algorithm/sift_down.h>
16 #include <__iterator/iterator_traits.h>
17 
18 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
19 #pragma GCC system_header
20 #endif
21 
22 _LIBCPP_PUSH_MACROS
23 #include <__undef_macros>
24 
25 _LIBCPP_BEGIN_NAMESPACE_STD
26 
27 template <class _Compare, class _RandomAccessIterator>
28 _LIBCPP_CONSTEXPR_AFTER_CXX11 void
29 __make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
30 {
31     typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
32     difference_type __n = __last - __first;
33     if (__n > 1)
34     {
35         // start from the first parent, there is no need to consider children
36         for (difference_type __start = (__n - 2) / 2; __start >= 0; --__start)
37         {
38             _VSTD::__sift_down<_Compare>(__first, __last, __comp, __n, __first + __start);
39         }
40     }
41 }
42 
43 template <class _RandomAccessIterator, class _Compare>
44 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
45 void
46 make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
47 {
48     typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
49     _VSTD::__make_heap<_Comp_ref>(__first, __last, __comp);
50 }
51 
52 template <class _RandomAccessIterator>
53 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
54 void
55 make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
56 {
57     _VSTD::make_heap(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
58 }
59 
60 _LIBCPP_END_NAMESPACE_STD
61 
62 _LIBCPP_POP_MACROS
63 
64 #endif // _LIBCPP___ALGORITHM_MAKE_HEAP_H
65