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/sift_down.h>
16 #include <__config>
17 #include <__iterator/iterator_traits.h>
18 #include <__utility/move.h>
19 
20 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
21 #  pragma GCC system_header
22 #endif
23 
24 _LIBCPP_BEGIN_NAMESPACE_STD
25 
26 template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
27 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11
28 void __make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare&& __comp) {
29   using _CompRef = typename __comp_ref_type<_Compare>::type;
30   _CompRef __comp_ref = __comp;
31 
32   using difference_type = typename iterator_traits<_RandomAccessIterator>::difference_type;
33   difference_type __n = __last - __first;
34   if (__n > 1) {
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         std::__sift_down<_AlgPolicy>(__first, __comp_ref, __n, __first + __start);
38     }
39   }
40 }
41 
42 template <class _RandomAccessIterator, class _Compare>
43 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
44 void make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
45   std::__make_heap<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __comp);
46 }
47 
48 template <class _RandomAccessIterator>
49 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
50 void make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last) {
51   std::make_heap(std::move(__first), std::move(__last),
52       __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
53 }
54 
55 _LIBCPP_END_NAMESPACE_STD
56 
57 #endif // _LIBCPP___ALGORITHM_MAKE_HEAP_H
58