xref: /llvm-project/libcxx/include/__algorithm/is_heap_until.h (revision 5aaefa510ef055e8f044ca89e352d4313f3aba49)
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_IS_HEAP_UNTIL_H
10 #define _LIBCPP___ALGORITHM_IS_HEAP_UNTIL_H
11 
12 #include <__algorithm/comp.h>
13 #include <__algorithm/comp_ref_type.h>
14 #include <__config>
15 #include <__iterator/iterator_traits.h>
16 
17 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
18 #  pragma GCC system_header
19 #  pragma clang include_instead(<algorithm>)
20 #endif
21 
22 _LIBCPP_BEGIN_NAMESPACE_STD
23 
24 template <class _Compare, class _RandomAccessIterator>
25 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 _RandomAccessIterator
26 __is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
27 {
28     typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
29     difference_type __len = __last - __first;
30     difference_type __p = 0;
31     difference_type __c = 1;
32     _RandomAccessIterator __pp = __first;
33     while (__c < __len)
34     {
35         _RandomAccessIterator __cp = __first + __c;
36         if (__comp(*__pp, *__cp))
37             return __cp;
38         ++__c;
39         ++__cp;
40         if (__c == __len)
41             return __last;
42         if (__comp(*__pp, *__cp))
43             return __cp;
44         ++__p;
45         ++__pp;
46         __c = 2 * __p + 1;
47     }
48     return __last;
49 }
50 
51 template <class _RandomAccessIterator, class _Compare>
52 _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 _RandomAccessIterator
53 is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)
54 {
55     typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
56     return _VSTD::__is_heap_until<_Comp_ref>(__first, __last, __comp);
57 }
58 
59 template<class _RandomAccessIterator>
60 _LIBCPP_NODISCARD_EXT inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 _RandomAccessIterator
61 is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last)
62 {
63     return _VSTD::__is_heap_until(__first, __last, __less<typename iterator_traits<_RandomAccessIterator>::value_type>());
64 }
65 
66 _LIBCPP_END_NAMESPACE_STD
67 
68 #endif // _LIBCPP___ALGORITHM_IS_HEAP_UNTIL_H
69