/*
* Insert a new node into an AVL tree at the specified (from avl_find()) place.
*
* Newly inserted nodes are always leaf nodes in the tree, since avl_find()
* searches out to the leaf positions. The avl_index_t indicates the node
* which will be the parent of the new node.
*
* After the node is inserted, a single rotation further up the tree may
* be necessary to maintain an acceptable AVL balance.
*/
void
avl_insert(avl_tree_t *tree, void *new_data, avl_index_t where)
{
avl_node_t *node;
avl_node_t *parent = AVL_INDEX2NODE(where);
int old_balance;
int new_balance;
int which_child = AVL_INDEX2CHILD(where);
size_t off = tree->avl_offset;
if (tree == NULL) {
filebench_log(LOG_ERROR, "No Tree Supplied");
return;
}
#if defined(_LP64) || (__WORDSIZE == 64)
if (((uintptr_t)new_data & 0x7) != 0) {
filebench_log(LOG_ERROR, "Missaligned pointer to new data");
return;
}
#endif
node = AVL_DATA2NODE(new_data, off);
/*
* First, add the node to the tree at the indicated position.
*/
++tree->avl_numnodes;
node->avl_child[0] = NULL;
node->avl_child[1] = NULL;
AVL_SETCHILD(node, which_child);
AVL_SETBALANCE(node, 0);
AVL_SETPARENT(node, parent);
if (parent != NULL) {
if (parent->avl_child[which_child] != NULL)
filebench_log(LOG_DEBUG_IMPL,
"Overwriting existing pointer");
parent->avl_child[which_child] = node;
} else {
if (tree->avl_root != NULL)
filebench_log(LOG_DEBUG_IMPL,
"Overwriting existing pointer");
tree->avl_root = node;
}
/*
* Now, back up the tree modifying the balance of all nodes above the
* insertion point. If we get to a highly unbalanced ancestor, we
* need to do a rotation. If we back out of the tree we are done.
* If we brought any subtree into perfect balance (0), we are also done.
*/
for (;;) {
node = parent;
if (node == NULL)
return;
/*
* Compute the new balance
*/
old_balance = AVL_XBALANCE(node);
new_balance = old_balance + avl_child2balance[which_child];
/*
* If we introduced equal balance, then we are done immediately
*/
if (new_balance == 0) {
AVL_SETBALANCE(node, 0);
return;
}
/*
* If both old and new are not zero we went
* from -1 to -2 balance, do a rotation.
*/
if (old_balance != 0)
break;
AVL_SETBALANCE(node, new_balance);
parent = AVL_XPARENT(node);
which_child = AVL_XCHILD(node);
}
/*
* perform a rotation to fix the tree and return
*/
(void) avl_rotation(tree, node, new_balance);
}
/*
* Insert a new node into an AVL tree at the specified (from avl_find()) place.
*
* Newly inserted nodes are always leaf nodes in the tree, since avl_find()
* searches out to the leaf positions. The avl_index_t indicates the node
* which will be the parent of the new node.
*
* After the node is inserted, a single rotation further up the tree may
* be necessary to maintain an acceptable AVL balance.
*/
void
avl_insert(avl_tree_t *tree, void *new_data, avl_index_t where)
{
avl_node_t *node;
avl_node_t *parent = AVL_INDEX2NODE(where);
int old_balance;
int new_balance;
int which_child = AVL_INDEX2CHILD(where);
size_t off = tree->avl_offset;
node = AVL_DATA2NODE(new_data, off);
/*
* First, add the node to the tree at the indicated position.
*/
++tree->avl_numnodes;
node->avl_child[0] = NULL;
node->avl_child[1] = NULL;
AVL_SETCHILD(node, which_child);
AVL_SETBALANCE(node, 0);
AVL_SETPARENT(node, parent);
if (parent != NULL) {
parent->avl_child[which_child] = node;
} else {
tree->avl_root = node;
}
/*
* Now, back up the tree modifying the balance of all nodes above the
* insertion point. If we get to a highly unbalanced ancestor, we
* need to do a rotation. If we back out of the tree we are done.
* If we brought any subtree into perfect balance (0), we are also done.
*/
for (;;) {
node = parent;
if (node == NULL)
return;
/*
* Compute the new balance
*/
old_balance = AVL_XBALANCE(node);
new_balance = old_balance + avl_child2balance[which_child];
/*
* If we introduced equal balance, then we are done immediately
*/
if (new_balance == 0) {
AVL_SETBALANCE(node, 0);
return;
}
/*
* If both old and new are not zero we went
* from -1 to -2 balance, do a rotation.
*/
if (old_balance != 0)
break;
AVL_SETBALANCE(node, new_balance);
parent = AVL_XPARENT(node);
which_child = AVL_XCHILD(node);
}
/*
* perform a rotation to fix the tree and return
*/
(void) avl_rotation(tree, node, new_balance);
}