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_index_block(self, index_node):
block_location = self.get_root_block()
while block_location != -1:
block = IndexBlock(block_location, self._index_name, self._index_directory)
block.read_block(self._fd)
for node in block.get_index_nodes():
if index_node.get_key() < node.get_key():
block_location = node.get_index_block_pointer()
break
elif index_node.get_key() == node.get_key():
return block, node
return None, None
def delete_index_node(self, index_node):
block, index_node = self.find_index_block(index_node)
if block is None:
print("Fail")
return
successor_block, successor_node = self.find_successor(block, index_node)
if block == successor_block:
successor_node.set_index_block_pointer(index_node.get_index_block_pointer())
block.delete_index_node(index_node)
if len(block.get_index_nodes()) == 1:
if block.get_location() != self.get_root_block():
parent_location = block.get_parent_block()
if parent_location != -1:
parent = IndexBlock(parent_location, self._index_name, self._index_directory)
parent.read_block(self._fd)
for node in parent.get_index_nodes():
if node.get_index_block_pointer() == block.get_location():
node.set_index_block_pointer(block.get_index_nodes()[0].get_index_block_pointer())
parent.update_child_blocks(self._fd)
parent.write_block(self._fd)
block.delete_block(self._fd, self.get_free_block_pointer())
else:
block.write_block(self._fd)
else:
block.write_block(self._fd)
else :
successor_block.delete_index_node(successor_node)
block.delete_index_node(index_node)
successor_node.set_index_block_pointer(index_node.get_index_block_pointer())
block.add_index_node(successor_node)
block.write_block(self._fd)
if len(successor_block.get_index_nodes()) == 1:
if successor_block.get_location() != self.get_root_block():
parent_location = successor_block.get_parent_block()
if parent_location != -1:
parent = IndexBlock(parent_location, self._index_name, self._index_directory)
parent.read_block(self._fd)
for node in parent.get_index_nodes():
if node.get_index_block_pointer() == successor_block.get_location():
node.set_index_block_pointer(successor_block.get_index_nodes()[0].get_index_block_pointer())
parent.update_child_blocks(self._fd)
parent.write_block(self._fd)
successor_block.delete_block(self._fd, self.get_free_block_pointer())
else:
successor_block.write_block(self._fd)
else:
successor_block.write_block(self._fd)
def find_index_node(self, key):
block_location = self.get_root_block()
while block_location != -1:
block = IndexBlock(block_location, self._index_name, self._index_directory)
block.read_block(self._fd)
flag = 0
for node in block.get_index_nodes():
if key < node.get_key():
flag = 1
block_location = node.get_index_block_pointer()
break
elif key == node.get_key():
return node.get_key(), node.get_value()
if flag == 0:
return key, None
return key,
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 find_successor(self, block, index_node):
index_nodes = block.get_index_nodes()
for i in range(len(index_nodes)):
if index_nodes[i].get_key() == index_node.get_key():
break
i += 1
if block.get_index_nodes()[i].get_index_block_pointer() == -1:
return block, index_nodes[i]
block_location = block.get_index_nodes()[i].get_index_block_pointer()
block = IndexBlock(block_location, self._index_name, self._index_directory)
block.read_block(self._fd)
while block.get_index_nodes()[0].get_index_block_pointer() != -1:
block_location = block.get_index_nodes()[0].get_index_block_pointer()
block = IndexBlock(block_location, self._index_name, self._index_directory)
block.read_block(self._fd)
return block, block.get_index_nodes()[0]