static void RLRotation(TLDNode *x, TLDList *tld)
{
TLDNode *k1, *k2, *k3, *p;
k1 = x;
k3 = k1->right;
k2 = k3->left;
p = k1->parent;
doubleRotate(k1,k2,k3,p, p != NULL && isLeftChild(k1), tld);
}
static TNode *insertBalance(TNode *root, int dir) {
TNode *n = root->link[dir];
int bal = (dir == 0) ? -1 : +1;
if (n->balance == bal) {
root->balance = n->balance = 0;
root = singleRotate(root, !dir);
} else { /* n->balance == -bal */
adjustBalance(root, dir, bal);
root = doubleRotate(root, !dir);
}
return root;
}
static TNode *removeBalance(TNode *root, int dir, int *done) {
TNode *n = root->link[!dir];
int bal = (dir == 0) ? -1 : +1;
if (n->balance == -bal) {
root->balance = n->balance = 0;
root = singleRotate(root, dir);
} else if (n->balance == bal) {
adjustBalance(root, !dir, -bal);
root = doubleRotate(root, dir);
} else { /* n->balance == 0 */
root->balance = -bal;
n->balance = bal;
root = singleRotate(root, dir);
*done = 1;
}
return root;
}
/**
* Rebalances an AVL tree.
* This function should be called with either walkPtr OR walkSRPPtr set.
* Use walkPtr if you have a direct pointer to the node or walkSRPPtr if you have a pointer to a WSRP
*
* @param[in] tree The tree
* @param[in] walkPtr A pointer to the root of the tree to balance (walkSRPPtr is NULL)
* @param[in] walkSRPPtr A pointer to an SRP of the root of the tree to balance (walkPtr is NULL)
* @param[in|out] heightChange The height change
*/
static void
rebalance(J9AVLTree *tree, J9AVLTreeNode **walkPtr, J9WSRP *walkSRPPtr, intptr_t direction, intptr_t *heightChange)
{
J9AVLTreeNode *walk = NULL;
uintptr_t walkBalance;
if (!(*heightChange)) {
return;
}
Trc_AVL_rebalance_Entry(tree, walkPtr, walkSRPPtr, direction, heightChange);
/* if we shrunk nodes, flip the direction, thus direction points towards heavy direction */
if (*heightChange < 0) {
direction = -direction;
}
/* Assumption is that if walkSRPPtr is NULL, walkPtr is not */
if (!walkSRPPtr) {
walk = AVL_GETNODE(*walkPtr);
} else {
walk = AVL_NNSRP_GETNODE(*walkSRPPtr);
}
walkBalance = AVL_GETBALANCE(walk);
if (walkBalance == AVL_BALANCED) {
AVL_SETBALANCE(walk, (direction < 0) ? AVL_LEFTHEAVY : AVL_RIGHTHEAVY);
/* if the tree was shrinking, we've just unbalanced a node .. no longer shrinking */
if (*heightChange < 0) {
*heightChange = 0;
}
} else if ((walkBalance == AVL_LEFTHEAVY) == (direction < 0)) {
J9AVLTreeNode *rotateResult = NULL;
/* left heavy adding to the left or right heavy adding to the right */
if ((direction < 0) && (AVL_GETBALANCE(AVL_NNSRP_GETNODE(walk->leftChild)) == AVL_RIGHTHEAVY)) {
/* doubleRotate */
rotateResult = (J9AVLTreeNode *)doubleRotate(tree, walk, -direction, heightChange);
} else if ((direction > 0) && (AVL_GETBALANCE(AVL_NNSRP_GETNODE(walk->rightChild)) == AVL_LEFTHEAVY)) {
/* doubleRotate */
rotateResult = (J9AVLTreeNode *)doubleRotate(tree, walk, -direction, heightChange);
} else {
/* single rotate */
rotateResult = (J9AVLTreeNode *)rotate(tree, walk, -direction, heightChange);
}
/* Assumption is that if walkSRPPtr is NULL, walkPtr is not */
if (!walkSRPPtr) {
AVL_SETNODE(*walkPtr, rotateResult);
} else {
AVL_NNSRP_PTR_SETNODE(walkSRPPtr, rotateResult);
}
} else {
AVL_SETBALANCE(walk, AVL_BALANCED);
/* added height making node become equal -- no more growing */
if (*heightChange > 0) {
*heightChange = 0;
}
}
Trc_AVL_rebalance_Exit(*heightChange);
}
