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

83 lines
2.3 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_H
#define _LIBCPP___ALGORITHM_PARTITION_H
#include <__config>
#include <__iterator/iterator_traits.h>
#include <__utility/swap.h>
#include <utility> // pair
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
template <class _Predicate, class _ForwardIterator>
_LIBCPP_CONSTEXPR_AFTER_CXX17 _ForwardIterator
__partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred, forward_iterator_tag)
{
while (true)
{
if (__first == __last)
return __first;
if (!__pred(*__first))
break;
++__first;
}
for (_ForwardIterator __p = __first; ++__p != __last;)
{
if (__pred(*__p))
{
swap(*__first, *__p);
++__first;
}
}
return __first;
}
template <class _Predicate, class _BidirectionalIterator>
_LIBCPP_CONSTEXPR_AFTER_CXX17 _BidirectionalIterator
__partition(_BidirectionalIterator __first, _BidirectionalIterator __last, _Predicate __pred,
bidirectional_iterator_tag)
{
while (true)
{
while (true)
{
if (__first == __last)
return __first;
if (!__pred(*__first))
break;
++__first;
}
do
{
if (__first == --__last)
return __first;
} while (!__pred(*__last));
swap(*__first, *__last);
++__first;
}
}
template <class _ForwardIterator, class _Predicate>
inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
_ForwardIterator
partition(_ForwardIterator __first, _ForwardIterator __last, _Predicate __pred)
{
return _VSTD::__partition<_Predicate&>(
__first, __last, __pred, typename iterator_traits<_ForwardIterator>::iterator_category());
}
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___ALGORITHM_PARTITION_H