def add_index(self, index_node, block=None):
key = index_node.get_key()
root_block_location = self.get_root_block()
if block is None:
block = self.find_leaf_block(key, root_block_location)
parent = block.get_parent_block()
block.add_index_node(index_node)
if block.get_size() < (0.80*self._block_size):
self.write_block(block)
if root_block_location == -1:
self.set_root_block(block.get_location())
return
new_block, median_node = self.split_block(block)
if parent != -1:
parent = self.read_block(parent)
self.write_block(block)
self.write_block(new_block)
self.add_index(median_node, parent)
else:
root_block = IndexBlock(self.get_free_block_pointer(), self._index_name, self._index_directory)
root_block.create_dummy_node()
root_block.set_dummy_node_pointer(block.get_location())
root_block.add_index_node(median_node)
block.set_parent_block(root_block.get_location())
new_block.set_parent_block(root_block.get_location())
self.set_root_block(root_block.get_location())
self.write_block(root_block)
self.write_block(new_block)
self.write_block(block)
def split_block(self, block):
index_nodes = block.get_index_nodes()
median = int(len(index_nodes)/2)
median_node = index_nodes[median]
new_block = IndexBlock(self.get_free_block_pointer(), self._index_name, self._index_directory)
new_block.create_dummy_node()
i = 0
while i < median:
new_block.add_index_node(index_nodes[i])
i += 1
new_block.set_dummy_node_pointer(median_node.get_index_block_pointer())
i = 0
while i <= median:
block.delete_index_node(index_nodes[0])
i += 1
self.update_child_blocks(new_block)
median_node.set_index_block_pointer(new_block.get_location())
new_block.set_parent_block(block.get_parent_block())
return new_block, median_node