xref: /freebsd/contrib/llvm-project/libcxx/include/__algorithm/make_heap.h (revision 397e83df75e0fcd0d3fcb95ae4d794cb7600fc89)
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_PUSH_MACROS
25 #include <__undef_macros>
26 
27 _LIBCPP_BEGIN_NAMESPACE_STD
28 
29 template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
30 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
31 __make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare&& __comp) {
32   __comp_ref_type<_Compare> __comp_ref = __comp;
33 
34   using difference_type = typename iterator_traits<_RandomAccessIterator>::difference_type;
35   difference_type __n   = __last - __first;
36   if (__n > 1) {
37     // start from the first parent, there is no need to consider children
38     for (difference_type __start = (__n - 2) / 2; __start >= 0; --__start) {
39       std::__sift_down<_AlgPolicy>(__first, __comp_ref, __n, __first + __start);
40     }
41   }
42 }
43 
44 template <class _RandomAccessIterator, class _Compare>
45 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
46 make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
47   std::__make_heap<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __comp);
48 }
49 
50 template <class _RandomAccessIterator>
51 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
52 make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last) {
53   std::make_heap(std::move(__first), std::move(__last), __less<>());
54 }
55 
56 _LIBCPP_END_NAMESPACE_STD
57 
58 _LIBCPP_POP_MACROS
59 
60 #endif // _LIBCPP___ALGORITHM_MAKE_HEAP_H
61