public bool Dequeue(out T item)
{
item = default(T);
SingleLinkNode oldHead = null;
bool haveAdvancedHead = false;
while (!haveAdvancedHead)
{
oldHead = head;
SingleLinkNode oldTail = tail;
SingleLinkNode oldHeadNext = oldHead.Next;
if (oldHead == head)
{
if (oldHead == oldTail)
{
if (oldHeadNext == null)
{
return(false);
}
CAS(ref tail, oldTail, oldHeadNext);
}
else
{
item = oldHeadNext.Item;
haveAdvancedHead = CAS(ref head, oldHead, oldHeadNext);
}
}
}
Interlocked.Decrement(ref count);
return(true);
}
public void Enqueue(T item)
{
SingleLinkNode oldTail = null;
SingleLinkNode oldTailNext;
SingleLinkNode newNode = new SingleLinkNode {
Item = item
};
bool newNodeWasAdded = false;
while (!newNodeWasAdded)
{
oldTail = tail;
oldTailNext = oldTail.Next;
if (tail == oldTail)
{
if (oldTailNext == null)
{
newNodeWasAdded = CAS(ref tail.Next, null, newNode);
}
else
{
CAS(ref tail, oldTail, oldTailNext);
}
}
}
CAS(ref tail, oldTail, newNode);
Interlocked.Increment(ref count);
}
public bool Dequeue(out T item)
{
item = default(T);
SingleLinkNode <T> oldHead = null;
bool haveAdvancedHead = false;
while (!haveAdvancedHead)
{
oldHead = head;
SingleLinkNode <T> oldTail = tail;
SingleLinkNode <T> oldHeadNext = oldHead.Next;
if (oldHead == head)
{
if (oldHead == oldTail)
{
if (oldHeadNext == null)
{
return(false);
}
SyncMethods.CAS(ref tail, oldTail, oldHeadNext);
}
else
{
item = oldHeadNext.Item;
haveAdvancedHead =
SyncMethods.CAS(ref head, oldHead, oldHeadNext);
}
}
}
return(true);
}
public void Enqueue(T item)
{
SingleLinkNode <T> oldTail = null;
SingleLinkNode <T> oldTailNext;
SingleLinkNode <T> newNode = new SingleLinkNode <T> {
Item = item
};
bool newNodeWasAdded = false;
while (!newNodeWasAdded)
{
oldTail = tail;
oldTailNext = oldTail.Next;
if (tail == oldTail)
{
if (oldTailNext == null)
{
newNodeWasAdded = SyncMethods.CAS(ref tail.Next, null, newNode);
}
else
{
SyncMethods.CAS(ref tail, oldTail, oldTailNext);
}
}
}
SyncMethods.CAS(ref tail, oldTail, newNode);
}
public bool Dequeue(int num, out List <T> items)
{
items = new List <T>(num);
SingleLinkNode oldHead = null;
bool haveAdvancedHead = false;
for (int i = 0; i < num; i++)
{
while (!haveAdvancedHead)
{
oldHead = head;
SingleLinkNode oldTail = tail;
SingleLinkNode oldHeadNext = oldHead.Next;
if (oldHead == head)
{
if (oldHead == oldTail)
{
if (oldHeadNext == null)
{
return(false);
}
CAS(ref tail, oldTail, oldHeadNext);
}
else
{
items.Add(oldHeadNext.Item);
haveAdvancedHead = CAS(ref head, oldHead, oldHeadNext);
}
}
}
}
Interlocked.Decrement(ref count);
return(true);
}
public LockFreeQueue()
{
head = new SingleLinkNode <T>();
tail = head;
}
private static bool CAS(ref SingleLinkNode location, SingleLinkNode comparand, SingleLinkNode newValue)
{
return
(comparand ==
Interlocked.CompareExchange(ref location, newValue, comparand));
}
private void Init()
{
count = 0;
head = tail = new SingleLinkNode();
}