xref: /openbsd-src/gnu/llvm/libcxx/include/__algorithm/partition_point.h (revision 4bdff4bed0e3d54e55670334c7d0077db4170f86)
176d0caaeSpatrick //===----------------------------------------------------------------------===//
276d0caaeSpatrick //
376d0caaeSpatrick // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
476d0caaeSpatrick // See https://llvm.org/LICENSE.txt for license information.
576d0caaeSpatrick // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
676d0caaeSpatrick //
776d0caaeSpatrick //===----------------------------------------------------------------------===//
876d0caaeSpatrick 
976d0caaeSpatrick #ifndef _LIBCPP___ALGORITHM_PARTITION_POINT_H
1076d0caaeSpatrick #define _LIBCPP___ALGORITHM_PARTITION_POINT_H
1176d0caaeSpatrick 
1276d0caaeSpatrick #include <__algorithm/half_positive.h>
13*4bdff4beSrobert #include <__config>
14*4bdff4beSrobert #include <__iterator/advance.h>
15*4bdff4beSrobert #include <__iterator/distance.h>
16*4bdff4beSrobert #include <__iterator/iterator_traits.h>
1776d0caaeSpatrick 
1876d0caaeSpatrick #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
1976d0caaeSpatrick #  pragma GCC system_header
2076d0caaeSpatrick #endif
2176d0caaeSpatrick 
2276d0caaeSpatrick _LIBCPP_BEGIN_NAMESPACE_STD
2376d0caaeSpatrick 
2476d0caaeSpatrick template<class _ForwardIterator, class _Predicate>
25*4bdff4beSrobert _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
partition_point(_ForwardIterator __first,_ForwardIterator __last,_Predicate __pred)2676d0caaeSpatrick partition_point(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
2776d0caaeSpatrick {
2876d0caaeSpatrick     typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
2976d0caaeSpatrick     difference_type __len = _VSTD::distance(__first, __last);
3076d0caaeSpatrick     while (__len != 0)
3176d0caaeSpatrick     {
3276d0caaeSpatrick         difference_type __l2 = _VSTD::__half_positive(__len);
3376d0caaeSpatrick         _ForwardIterator __m = __first;
3476d0caaeSpatrick         _VSTD::advance(__m, __l2);
3576d0caaeSpatrick         if (__pred(*__m))
3676d0caaeSpatrick         {
3776d0caaeSpatrick             __first = ++__m;
3876d0caaeSpatrick             __len -= __l2 + 1;
3976d0caaeSpatrick         }
4076d0caaeSpatrick         else
4176d0caaeSpatrick             __len = __l2;
4276d0caaeSpatrick     }
4376d0caaeSpatrick     return __first;
4476d0caaeSpatrick }
4576d0caaeSpatrick 
4676d0caaeSpatrick _LIBCPP_END_NAMESPACE_STD
4776d0caaeSpatrick 
4876d0caaeSpatrick #endif // _LIBCPP___ALGORITHM_PARTITION_POINT_H
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