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() < self._block_size: block.write_block(self._fd) 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 = IndexBlock(parent, self._index_name, self._index_directory) parent.read_block(self._fd) block.write_block(self._fd) new_block.write_block(self._fd) 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.get_index_nodes()[-1].set_index_block_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()) root_block.write_block(self._fd) new_block.write_block(self._fd) block.write_block(self._fd)
def find_leaf_block(self, key, root): if root == -1: block = IndexBlock(self.get_free_block_pointer(), self._index_name, self._index_directory) block.create_dummy_node() return block block = self.read_block(root) parent = -1 while not block.is_leaf(): parent = block.get_location() index_nodes = block.get_index_nodes() flag = 0 for node in index_nodes: if key < node.get_key(): flag = 1 block_location = node.get_index_block_pointer() break if flag == 0: block_location = block.get_dummy_node_pointer() if block_location == -1: return self.read_block(parent) if block_location == None: x = 1 block = self.read_block(block_location) return block
def find_leaf_block(self, key, root): if root == -1: block = IndexBlock(self.get_free_block_pointer(), self._index_name, self._index_directory) block.create_dummy_node() return block block = IndexBlock(root, self._index_name, self._index_directory) parent = -1 block.read_block(self._fd) while not block.is_leaf(): parent = block.get_location() index_nodes = block.get_index_nodes() for node in index_nodes: if key < node.get_key(): block = IndexBlock(node.get_index_block_pointer(), self._index_name, self._index_directory) break if block.get_location() == -1: return parent block.read_block(self._fd) return block
def split_block(self, block): index_nodes = block.get_index_nodes() median = int(len(index_nodes)/2 - 1) 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.get_index_nodes()[-1].set_index_block_pointer(median_node.get_index_block_pointer()) i = 0 while i <= median: block.delete_index_node(index_nodes[0]) i += 1 new_block.update_child_blocks(self._fd) median_node.set_index_block_pointer(new_block.get_location()) new_block.set_parent_block(block.get_parent_block()) return new_block, median_node