push_heap.h revision 1.1.1.2 
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
26template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
27_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
28void __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
52template <class _AlgPolicy, class _RandomAccessIterator, class _Compare>
53inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
54void __push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare& __comp) {
55  typename iterator_traits<_RandomAccessIterator>::difference_type __len = __last - __first;
56  std::__sift_up<_AlgPolicy, __comp_ref_type<_Compare> >(std::move(__first), std::move(__last), __comp, __len);
57}
58
59template <class _RandomAccessIterator, class _Compare>
60inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
61void push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
62  static_assert(std::is_copy_constructible<_RandomAccessIterator>::value, "Iterators must be copy constructible.");
63  static_assert(std::is_copy_assignable<_RandomAccessIterator>::value, "Iterators must be copy assignable.");
64
65  std::__push_heap<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __comp);
66}
67
68template <class _RandomAccessIterator>
69inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
70void push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last) {
71  std::push_heap(std::move(__first), std::move(__last),
72      __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
73}
74
75_LIBCPP_END_NAMESPACE_STD
76
77#endif // _LIBCPP___ALGORITHM_PUSH_HEAP_H
78