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_PARTITION_POINT_H
10 #define _LIBCPP___ALGORITHM_PARTITION_POINT_H
11 
12 #include <__algorithm/half_positive.h>
13 #include <__config>
14 #include <__iterator/advance.h>
15 #include <__iterator/distance.h>
16 #include <__iterator/iterator_traits.h>
17 
18 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
19 #  pragma GCC system_header
20 #endif
21 
22 _LIBCPP_BEGIN_NAMESPACE_STD
23 
24 template<class _ForwardIterator, class _Predicate>
25 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
26 partition_point(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
27 {
28     typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
29     difference_type __len = _VSTD::distance(__first, __last);
30     while (__len != 0)
31     {
32         difference_type __l2 = _VSTD::__half_positive(__len);
33         _ForwardIterator __m = __first;
34         _VSTD::advance(__m, __l2);
35         if (__pred(*__m))
36         {
37             __first = ++__m;
38             __len -= __l2 + 1;
39         }
40         else
41             __len = __l2;
42     }
43     return __first;
44 }
45 
46 _LIBCPP_END_NAMESPACE_STD
47 
48 #endif // _LIBCPP___ALGORITHM_PARTITION_POINT_H
49