/*
* Extend a priority search tree so that it can store a node with heap_index
* max_heap_index. In the worst case, this algorithm takes O((log n)^2).
* However, this function is used rarely and the common case performance is
* not bad.
*/
static struct prio_tree_node *prio_tree_expand(struct prio_tree_root *root,
struct prio_tree_node *node, unsigned long max_heap_index)
{
struct prio_tree_node *prev;
if (max_heap_index > prio_tree_maxindex(root->index_bits))
root->index_bits++;
prev = node;
INIT_PRIO_TREE_NODE(node);
while (max_heap_index > prio_tree_maxindex(root->index_bits)) {
struct prio_tree_node *tmp = root->prio_tree_node;
root->index_bits++;
if (prio_tree_empty(root))
continue;
prio_tree_remove(root, root->prio_tree_node);
INIT_PRIO_TREE_NODE(tmp);
prio_set_parent(prev, tmp, true);
prev = tmp;
}
if (!prio_tree_empty(root))
prio_set_parent(prev, root->prio_tree_node, true);
root->prio_tree_node = node;
return node;
}
/*
* Extend a priority search tree so that it can store a node with heap_index
* max_heap_index. In the worst case, this algorithm takes O((log n)^2).
* However, this function is used rarely and the common case performance is
* not bad.
*/
static struct prio_tree_node *prio_tree_expand(struct prio_tree_root *root,
struct prio_tree_node *node, unsigned long max_heap_index)
{
struct prio_tree_node *first = NULL, *prev, *last = NULL;
if (max_heap_index > prio_tree_maxindex(root->index_bits))
root->index_bits++;
while (max_heap_index > prio_tree_maxindex(root->index_bits)) {
root->index_bits++;
if (prio_tree_empty(root))
continue;
if (first == NULL) {
first = root->prio_tree_node;
prio_tree_remove(root, root->prio_tree_node);
INIT_PRIO_TREE_NODE(first);
last = first;
} else {
prev = last;
last = root->prio_tree_node;
prio_tree_remove(root, root->prio_tree_node);
INIT_PRIO_TREE_NODE(last);
prev->left = last;
last->parent = prev;
}
}
INIT_PRIO_TREE_NODE(node);
if (first) {
node->left = first;
first->parent = node;
} else
last = node;
if (!prio_tree_empty(root)) {
last->left = root->prio_tree_node;
last->left->parent = last;
}
root->prio_tree_node = node;
return node;
}