xref: /freebsd-src/contrib/llvm-project/libcxx/include/__algorithm/partition_point.h (revision cb14a3fe5122c879eae1fb480ed7ce82a699ddb6)
1fe6060f1SDimitry Andric //===----------------------------------------------------------------------===//
2fe6060f1SDimitry Andric //
3fe6060f1SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4fe6060f1SDimitry Andric // See https://llvm.org/LICENSE.txt for license information.
5fe6060f1SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6fe6060f1SDimitry Andric //
7fe6060f1SDimitry Andric //===----------------------------------------------------------------------===//
8fe6060f1SDimitry Andric 
9fe6060f1SDimitry Andric #ifndef _LIBCPP___ALGORITHM_PARTITION_POINT_H
10fe6060f1SDimitry Andric #define _LIBCPP___ALGORITHM_PARTITION_POINT_H
11fe6060f1SDimitry Andric 
12fe6060f1SDimitry Andric #include <__algorithm/half_positive.h>
1304eeddc0SDimitry Andric #include <__config>
1481ad6265SDimitry Andric #include <__iterator/advance.h>
1581ad6265SDimitry Andric #include <__iterator/distance.h>
1681ad6265SDimitry Andric #include <__iterator/iterator_traits.h>
17fe6060f1SDimitry Andric 
18fe6060f1SDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
19fe6060f1SDimitry Andric #  pragma GCC system_header
20fe6060f1SDimitry Andric #endif
21fe6060f1SDimitry Andric 
22fe6060f1SDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD
23fe6060f1SDimitry Andric 
24fe6060f1SDimitry Andric template <class _ForwardIterator, class _Predicate>
25bdd1243dSDimitry Andric _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
partition_point(_ForwardIterator __first,_ForwardIterator __last,_Predicate __pred)26*cb14a3feSDimitry Andric partition_point(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred) {
27fe6060f1SDimitry Andric   typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
285f757f3fSDimitry Andric   difference_type __len = std::distance(__first, __last);
29*cb14a3feSDimitry Andric   while (__len != 0) {
305f757f3fSDimitry Andric     difference_type __l2 = std::__half_positive(__len);
31fe6060f1SDimitry Andric     _ForwardIterator __m = __first;
325f757f3fSDimitry Andric     std::advance(__m, __l2);
33*cb14a3feSDimitry Andric     if (__pred(*__m)) {
34fe6060f1SDimitry Andric       __first = ++__m;
35fe6060f1SDimitry Andric       __len -= __l2 + 1;
36*cb14a3feSDimitry Andric     } else
37fe6060f1SDimitry Andric       __len = __l2;
38fe6060f1SDimitry Andric   }
39fe6060f1SDimitry Andric   return __first;
40fe6060f1SDimitry Andric }
41fe6060f1SDimitry Andric 
42fe6060f1SDimitry Andric _LIBCPP_END_NAMESPACE_STD
43fe6060f1SDimitry Andric 
44fe6060f1SDimitry Andric #endif // _LIBCPP___ALGORITHM_PARTITION_POINT_H
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