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_PUSH_HEAP_H
10 #define _LIBCPP___ALGORITHM_PUSH_HEAP_H
11 
12 #include <__algorithm/comp.h>
13 #include <__algorithm/comp_ref_type.h>
14 #include <__algorithm/iterator_operations.h>
15 #include <__config>
16 #include <__iterator/iterator_traits.h>
17 #include <__utility/move.h>
18 #include <type_traits>
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 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11
28 void __sift_up(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare&& __comp,
29         typename iterator_traits<_RandomAccessIterator>::difference_type __len) {
30   using value_type = typename iterator_traits<_RandomAccessIterator>::value_type;
31 
32   if (__len > 1) {
33     __len = (__len - 2) / 2;
34     _RandomAccessIterator __ptr = __first + __len;
35 
36     if (__comp(*__ptr, *--__last)) {
37       value_type __t(_IterOps<_AlgPolicy>::__iter_move(__last));
38       do {
39         *__last = _IterOps<_AlgPolicy>::__iter_move(__ptr);
40         __last = __ptr;
41         if (__len == 0)
42           break;
43         __len = (__len - 1) / 2;
44         __ptr = __first + __len;
45       } while (__comp(*__ptr, __t));
46 
47       *__last = std::move(__t);
48     }
49   }
50 }
51 
52 template <class _AlgPolicy, class _RandomAccessIterator, class _Compare>
53 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11
54 void __push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare& __comp) {
55   using _CompRef = typename __comp_ref_type<_Compare>::type;
56   typename iterator_traits<_RandomAccessIterator>::difference_type __len = __last - __first;
57   std::__sift_up<_AlgPolicy, _CompRef>(std::move(__first), std::move(__last), __comp, __len);
58 }
59 
60 template <class _RandomAccessIterator, class _Compare>
61 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
62 void push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
63   static_assert(std::is_copy_constructible<_RandomAccessIterator>::value, "Iterators must be copy constructible.");
64   static_assert(std::is_copy_assignable<_RandomAccessIterator>::value, "Iterators must be copy assignable.");
65 
66   std::__push_heap<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __comp);
67 }
68 
69 template <class _RandomAccessIterator>
70 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17
71 void push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last) {
72   std::push_heap(std::move(__first), std::move(__last),
73       __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
74 }
75 
76 _LIBCPP_END_NAMESPACE_STD
77 
78 #endif // _LIBCPP___ALGORITHM_PUSH_HEAP_H
79