private static IEnumerator <T> Enumerate(RopeNode <T> node)
{
var stack = new Stack <RopeNode <T> >();
while (node != null)
{
// go to leftmost node, pushing the right parts that we'll have to visit later
while (node.contents == null)
{
if (node.height == 0)
{
// go down into function nodes
node = node.GetContentNode();
continue;
}
Debug.Assert(node.right != null);
stack.Push(node.right);
node = node.left;
}
// yield contents of leaf node
for (var i = 0; i < node.length; i++)
{
yield return(node.contents[i]);
}
// go up to the next node not visited yet
if (stack.Count > 0)
{
node = stack.Pop();
}
else
{
node = null;
}
}
}
internal static void WriteTo(this RopeNode <char> node, int index, TextWriter output, int count)
{
if (node.height == 0)
{
if (node.contents == null)
{
// function node
node.GetContentNode().WriteTo(index, output, count);
}
else
{
// leaf node: append data
output.Write(node.contents, index, count);
}
}
else
{
// concat node: do recursive calls
if (index + count <= node.left.length)
{
node.left.WriteTo(index, output, count);
}
else if (index >= node.left.length)
{
node.right.WriteTo(index - node.left.length, output, count);
}
else
{
var amountInLeft = node.left.length - index;
node.left.WriteTo(index, output, amountInLeft);
node.right.WriteTo(0, output, count - amountInLeft);
}
}
}
private void GoToLeftMostLeaf()
{
while (currentNode.contents == null)
{
if (currentNode.height == 0)
{
// this is a function node - move to its contained rope
currentNode = currentNode.GetContentNode();
continue;
}
Debug.Assert(currentNode.right != null);
stack.Push(currentNode.right);
currentNode = currentNode.left;
}
Debug.Assert(currentNode.height == 0);
}