static DirectNode *
tree_node_balance (DirectNode *node)
{
if (node->balance < -1) {
if (node->left->balance > 0)
node->left = tree_node_rotate_left (node->left);
node = tree_node_rotate_right (node);
}
else if (node->balance > 1) {
if (node->right->balance < 0)
node->right = tree_node_rotate_right (node->right);
node = tree_node_rotate_left (node);
}
return node;
}
/* Balance the tree with respect to node */
static int tree_node_balance(Edata_Tree *tree, Edata_Tree_Node *top_node)
{
int balance;
CHECK_PARAM_POINTER_RETURN("top_node", top_node, FALSE);
/* Get the height of the left branch. */
if (top_node->right_child)
top_node->max_left = MAX_HEIGHT(top_node->right_child) + 1;
else
top_node->max_left = 0;
/* Get the height of the right branch. */
if (top_node->left_child)
top_node->max_right = MAX_HEIGHT(top_node->left_child) + 1;
else
top_node->max_right = 0;
/* Determine which side has a larger height. */
balance = top_node->max_right - top_node->max_left;
/* if the left side has a height advantage >1 rotate right */
if (balance < -1)
tree_node_rotate_right(tree, top_node);
/* else if the left side has a height advantage >1 rotate left */
else if (balance > 1)
tree_node_rotate_left(tree, top_node);
return TRUE;
}
