llvm-project/libcxx/include/__algorithm/partition_point.h

49 lines
1.5 KiB
C++

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___ALGORITHM_PARTITION_POINT_H
#define _LIBCPP___ALGORITHM_PARTITION_POINT_H
#include <__algorithm/half_positive.h>
#include <__config>
#include <__iterator/advance.h>
#include <__iterator/distance.h>
#include <__iterator/iterator_traits.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
template<class _ForwardIterator, class _Predicate>
_LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
partition_point(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
{
typedef typename iterator_traits<_ForwardIterator>::difference_type difference_type;
difference_type __len = _VSTD::distance(__first, __last);
while (__len != 0)
{
difference_type __l2 = _VSTD::__half_positive(__len);
_ForwardIterator __m = __first;
_VSTD::advance(__m, __l2);
if (__pred(*__m))
{
__first = ++__m;
__len -= __l2 + 1;
}
else
__len = __l2;
}
return __first;
}
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___ALGORITHM_PARTITION_POINT_H