private void PreProcess()
{
// Eulerian path visit of graph
Stack <ProcessingState> lastNodeStack = new Stack <ProcessingState>();
ProcessingState current = new ProcessingState(_rootNode);
ITreeNode <T> next;
lastNodeStack.Push(current);
NodeIndex nodeIndex;
int valueIndex;
while (lastNodeStack.Count != 0)
{
current = lastNodeStack.Pop();
if (!_indexLookup.TryGetValue(current.Value, out nodeIndex))
{
valueIndex = _nodes.Count;
_nodes.Add(current.Value);
_indexLookup[current.Value] = new NodeIndex(_values.Count, valueIndex);
}
else
{
valueIndex = nodeIndex.LookupIndex;
}
_values.Add(valueIndex);
// If there is a next then push the current value on to the stack along with
// the current value.
if (current.Next(out next))
{
lastNodeStack.Push(current);
lastNodeStack.Push(new ProcessingState(next));
}
}
_nodes.TrimExcess();
_values.TrimExcess();
}