private void Sort(int parentNodeIndex, IComparer <int> nodeIndexComparer, ref PartialArray <int> buffer)
{
int currentChild = _firstChildIndex[parentNodeIndex];
// If no children, return
if (currentChild <= 0)
{
return;
}
// Add all children of the current element to the buffer
buffer.Clear();
while (currentChild > 0)
{
buffer.Add(currentChild);
currentChild = _nextSiblingIndex[currentChild];
}
// Sort the children by the compare function
buffer.Sort(nodeIndexComparer);
// Modify the FirstChild and NextSibling pointers to be in sorted order
currentChild = buffer[0];
_firstChildIndex[parentNodeIndex] = currentChild;
for (int i = 1; i < buffer.Count; ++i)
{
int nextChild = buffer[i];
_nextSiblingIndex[currentChild] = nextChild;
currentChild = nextChild;
}
_nextSiblingIndex[currentChild] = -1;
// Recurse on the children
currentChild = _firstChildIndex[parentNodeIndex];
while (currentChild > 0)
{
Sort(currentChild, nodeIndexComparer, ref buffer);
currentChild = _nextSiblingIndex[currentChild];
}
}
