/* Inserts the given NODE into BT.
Returns a null pointer if successful.
Returns the existing node already in BT equal to NODE, on
failure. */
static struct Node *insert(TreeMap *bt, struct Node *node,void *ExtraArgs)
{
size_t depth = 0;
node->down[0] = NULL;
node->down[1] = NULL;
if (bt->root == NULL) {
bt->root = node;
node->up = NULL;
}
else {
struct Node *p = bt->root;
for (;;) {
int cmp, dir;
cmp = bt->compare(node->data, p->data, ExtraArgs);
if (cmp == 0)
return p;
depth++;
dir = cmp > 0;
if (p->down[dir] == NULL)
{
p->down[dir] = node;
node->up = p;
break;
}
p = p->down[dir];
}
}
bt->count++;
if (bt->count > bt->max_size)
bt->max_size = bt->count;
if (depth > calculate_h_alpha (bt->count)) {
/* We use the "alternative" method of finding a scapegoat
node described by Galperin and Rivest. */
struct Node *s = node;
size_t size = 1;
size_t i;
for (i = 1; ; i++)
if (i < depth) {
size += 1 + count_nodes_in_subtree (sibling (s));
s = s->up;
if (i > calculate_h_alpha (size)) {
rebalance_subtree (bt, s, size);
break;
}
}
else {
rebalance_subtree (bt, bt->root, bt->count);
bt->max_size = bt->count;
break;
}
}
bt->timestamp++;
return NULL;
}
/* Inserts the given NODE into BT.
Returns a null pointer if successful.
Returns the existing node already in BT equal to NODE, on
failure. */
struct bt_node *
bt_insert (struct bt *bt, struct bt_node *node)
{
int depth = 0;
node->down[0] = NULL;
node->down[1] = NULL;
if (bt->root == NULL)
{
bt->root = node;
node->up = NULL;
}
else
{
struct bt_node *p = bt->root;
for (;;)
{
int cmp, dir;
cmp = bt->compare (node, p, bt->aux);
if (cmp == 0)
return p;
depth++;
dir = cmp > 0;
if (p->down[dir] == NULL)
{
p->down[dir] = node;
node->up = p;
break;
}
p = p->down[dir];
}
}
bt->size++;
if (bt->size > bt->max_size)
bt->max_size = bt->size;
if (depth > calculate_h_alpha (bt->size))
{
/* We use the "alternative" method of finding a scapegoat
node described by Galperin and Rivest. */
struct bt_node *s = node;
size_t size = 1;
int i;
for (i = 1; ; i++)
if (i < depth)
{
size += 1 + count_nodes_in_subtree (sibling (s));
s = s->up;
if (i > calculate_h_alpha (size))
{
rebalance_subtree (bt, s, size);
break;
}
}
else
{
rebalance_subtree (bt, bt->root, bt->size);
bt->max_size = bt->size;
break;
}
}
return NULL;
}
static size_t Size(TreeMap *tree)
{
return count_nodes_in_subtree(tree->root);
}
