func fillFailure(curr, root, parent *trie.TernaryNode) {
data := getNodeData(curr)
if data == nil {
data = &Data{}
curr.SetValue(data)
}
if parent == root {
data.failure = root
return
}
// Determine failure node.
fnode := getNextNode(getNodeFailure(parent, root), root, curr.Label())
data.failure = fnode
}
