int split_insert (PBTREE btree, int node_idx, PBTREE_ELEMENT element) {
int i;
int split_point;
int new_node_idx;
BTREE_ELEMENT upward_element;
// split_insert should only be called if node is full
if (btree->nodes[node_idx].element_count != BTREE_MAX_ELEMENTS-1)
return 0;
vector_insert_for_split (btree, node_idx, element);
split_point = btree->nodes[node_idx].element_count/2;
if (2*split_point < btree->nodes[node_idx].element_count) // perform the "ceiling function"
split_point++;
// new node receives the rightmost half of elements in *this node
new_node_idx = get_free_node(btree);
if (!BTREE_IS_VALID_NODE_IDX(new_node_idx))
return 0;
memcpy(&upward_element, &btree->nodes[node_idx].elements[split_point], sizeof(BTREE_ELEMENT));
insert_zeroth_subtree (btree, new_node_idx, upward_element.subtree_node_idx);
upward_element.subtree_node_idx = new_node_idx;
// element that gets added to the parent of this node
for (i=1; i<btree->nodes[node_idx].element_count-split_point; i++)
vector_insert(btree, new_node_idx, &btree->nodes[node_idx].elements[split_point+i]);
btree->nodes[new_node_idx].element_count = btree->nodes[node_idx].element_count-split_point;
btree->nodes[node_idx].element_count = split_point;
btree->nodes[new_node_idx].parent_node_idx = btree->nodes[node_idx].parent_node_idx;
// now insert the new node into the parent, splitting it if necessary
if (BTREE_IS_VALID_NODE_IDX(btree->nodes[node_idx].parent_node_idx) &&
vector_insert(btree, btree->nodes[node_idx].parent_node_idx, &upward_element))
return 1;
else if (BTREE_IS_VALID_NODE_IDX(btree->nodes[node_idx].parent_node_idx) &&
split_insert(btree, btree->nodes[node_idx].parent_node_idx, &upward_element))
return 1;
else if (!BTREE_IS_VALID_NODE_IDX(btree->nodes[node_idx].parent_node_idx)) { // this node was the root
int new_root = get_free_node(btree);
insert_zeroth_subtree(btree, new_root, node_idx);
btree->nodes[node_idx].parent_node_idx = new_root;
btree->nodes[new_node_idx].parent_node_idx = new_root;
vector_insert (btree, new_root, &upward_element);
btree->root_node_idx = new_root;
btree->nodes[new_root].parent_node_idx = BTREE_INVALID_NODE_IDX;
}
return 1;
}
template<class KEY, class VALUE> Nde::Node(RootTracker<KEY, VALUE>& root_track) : m_root(root_track) {
// limit the size of the vector to 4 kilobytes max and 200 entries max.
int num_elements = max_elements*sizeof(Elem)<=max_array_bytes ?
max_elements : max_array_bytes/sizeof(Elem);
// in case key or payload is really huge
if (num_elements < 6){ num_elements = 6;}
m_vector.resize (num_elements);
m_count = 0;
m_total_nodes = 0;
mp_parent = 0;
insert_zeroth_subtree (0);
}
int btree_insert (PBTREE btree, PBTREE_ELEMENT element) {
int last_visited_node_idx;
if (!BTREE_IS_VALID_NODE_IDX(btree->root_node_idx))
{
int node_idx = get_free_node(btree);
if (!BTREE_IS_VALID_NODE_IDX(node_idx))
return 0;
else
{
set_root(btree, node_idx);
insert_zeroth_subtree (btree, node_idx, BTREE_INVALID_NODE_IDX);
}
}
last_visited_node_idx = btree->root_node_idx;
if (btree_search_ex(btree, &last_visited_node_idx, element->key)) // element already in tree
return 0;
if (vector_insert(btree, last_visited_node_idx, element))
return 1;
return split_insert(btree, last_visited_node_idx, element);
}
