public static void validate(@Nullable Node original, Node n) {
if (original != null) {
validate(null, original);
}
if (Null.red) {
trouble(original, n, new RuntimeException("red null!"));
}
if (Null.left != Null || Null.right != Null || Null.value != Null || Null.key != null) {
trouble(original, n, new RuntimeException("corrupted null!"));
}
if (n.red) {
trouble(original, n, new RuntimeException("red root!"));
}
NodeStack s = new NodeStack();
int blackCount = -1;
for (NodeIterator it = new NodeIterator(s, n); it.hasNext(); ) {
int index = it.stack.index;
Node x = it.next();
if (x.key instanceof Node) {
trouble(original, n, new RuntimeException("node key!"));
}
if (x.key == null) {
trouble(original, n, new RuntimeException("null key!"));
}
if (x.value instanceof Node) {
validate(original, (Node) x.value);
}
if (x.red && (x.left.red || x.right.red)) {
trouble(original, n, new RuntimeException("red node has red child(ren)!"));
}
if (x.left == Node.Null && x.right == Node.Null) {
int count = 0;
for (int i = 0; i < index; ++i) {
if (!s.array[i].red) {
++count;
}
}
if (!x.red) {
++count;
}
if (blackCount == -1) {
blackCount = count;
} else if (count != blackCount) {
trouble(
original,
n,
new RuntimeException("inconsistent number of black nodes per paths to leaves!"));
}
}
}
}
