private void Promote(MTNameTableNode node)
{
// count number of times promotion requested
node.counter++;
if (node != rootNode &&
node.counter > threshhold &&
node.counter > node.parentNode.counter * 2)
{
if (rwLock != null)
{
LockCookie lc = rwLock.UpgradeToWriterLock(timeout);
// recheck for failsafe against race-condition
if (node != rootNode &&
node.counter > threshhold &&
node.counter > node.parentNode.counter * 2)
{
InternalPromote(node);
}
rwLock.DowngradeFromWriterLock(ref lc);
}
else
{
InternalPromote(node);
}
}
}
// <doc>
// <desc>
// Adds the a node to the right of the specified node, given a string.
// </desc>
// </doc>
//
private MTNameTableNode AddRight(MTNameTableNode node, ref MTNameTableName name, bool fLock)
{
MTNameTableNode newNode = null;
if (fLock)
{
LockCookie lc = rwLock.UpgradeToWriterLock(timeout);
// recheck for failsafe against race-condition
if (node.rightNode == null)
{
newNode = new MTNameTableNode(ref name);
node.rightNode = newNode;
newNode.parentNode = node;
}
else
{
// try again, with write-lock active
newNode = Add(ref name, false);
}
rwLock.DowngradeFromWriterLock(ref lc);
}
else
{
newNode = new MTNameTableNode(ref name);
node.rightNode = newNode;
newNode.parentNode = node;
}
return(newNode);
}
private MTNameTableNode Add(ref MTNameTableName name, bool fLock)
{
if (fLock)
{
rwLock.AcquireReaderLock(timeout);
}
MTNameTableNode currentNode = rootNode;
while (true)
{
if (currentNode == null)
{
currentNode = AddRoot(ref name, fLock);
break;
}
else
{
Int64 d = currentNode.Compare(ref name);
if (d == 0)
{
Promote(currentNode);
break;
}
else if (d < 0)
{
if (currentNode.leftNode == null)
{
currentNode = AddLeft(currentNode, ref name, fLock);
break;
}
else
{
currentNode = currentNode.leftNode;
}
}
else
{
if (currentNode.rightNode == null)
{
currentNode = AddRight(currentNode, ref name, fLock);
break;
}
else
{
currentNode = currentNode.rightNode;
}
}
}
}
if (fLock)
{
rwLock.ReleaseReaderLock();
}
return(currentNode);
}
private void InternalPromote(MTNameTableNode node)
{
MTNameTableNode parent = node.parentNode;
if (parent != null)
{
MTNameTableNode grandParent = parent.parentNode;
if (parent.leftNode == node)
{
parent.leftNode = node.rightNode;
node.rightNode = parent;
// update lineage
if (parent.leftNode != null)
{
parent.leftNode.parentNode = parent;
}
node.parentNode = grandParent;
parent.parentNode = node;
}
else
{
parent.rightNode = node.leftNode;
node.leftNode = parent;
// update lineage
if (parent.rightNode != null)
{
parent.rightNode.parentNode = parent;
}
node.parentNode = grandParent;
parent.parentNode = node;
}
// fixup pointer to promoted node in grand parent
if (grandParent == null)
{
rootNode = node;
}
else
{
if (grandParent.leftNode == parent)
{
grandParent.leftNode = node;
}
else
{
grandParent.rightNode = node;
}
}
}
}
private String Get(ref MTNameTableName nn)
{
String name = null;
if (rootNode != null)
{
if (rwLock != null)
{
rwLock.AcquireReaderLock(timeout);
}
MTNameTableNode currentNode = rootNode;
while (true)
{
Int64 d = currentNode.Compare(ref nn);
if (d == 0)
{
Promote(currentNode);
name = currentNode.value;
break;
}
else if (d < 0)
{
if (currentNode.leftNode == null)
{
break;
}
currentNode = currentNode.leftNode;
}
else
{
if (currentNode.rightNode == null)
{
break;
}
currentNode = currentNode.rightNode;
}
}
if (rwLock != null)
{
rwLock.ReleaseReaderLock();
}
}
return(name);
}
internal void Walk(MTNameTableNode node)
{
if (node != null)
{
if (node.leftNode != null)
{
Walk(node.leftNode);
}
names.Add(node.value);
if (node.rightNode != null)
{
Walk(node.rightNode);
}
}
}
internal void Walk( MTNameTableNode node ) {
if (node != null) {
if (node.leftNode != null)
Walk( node.leftNode );
names.Add( node.value );
if (node.rightNode != null)
Walk( node.rightNode );
}
}
