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/*
* LocklessList.h - list with lockless push and pop
*
* Copyright (c) 2016 Javier Serrano Polo <javier@jasp.net>
*
* This file is part of LMMS - https://lmms.io
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program (see COPYING); if not, write to the
* Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301 USA.
*
*/
#ifndef LOCKLESS_LIST_H
#define LOCKLESS_LIST_H
#include <QAtomicPointer>
#include "LocklessAllocator.h"
template<typename T>
class LocklessList
{
public:
struct Element
{
T value;
Element * next;
} ;
LocklessList( size_t size )
{
m_allocator = new LocklessAllocatorT<Element>( size );
}
~LocklessList()
{
delete m_allocator;
}
void push( T value )
{
Element * e = m_allocator->alloc();
e->value = value;
do
{
#if QT_VERSION >= 0x050000
e->next = m_first.loadAcquire();
#else
e->next = m_first;
#endif
}
while( !m_first.testAndSetOrdered( e->next, e ) );
}
Element * popList()
{
return m_first.fetchAndStoreOrdered( NULL );
}
Element * first()
{
#if QT_VERSION >= 0x050000
return m_first.loadAcquire();
#else
return m_first;
#endif
}
void setFirst( Element * e )
{
#if QT_VERSION >= 0x050000
m_first.storeRelease( e );
#else
m_first = e;
#endif
}
void free( Element * e )
{
m_allocator->free( e );
}
private:
QAtomicPointer<Element> m_first;
LocklessAllocatorT<Element> * m_allocator;
} ;
#endif
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