def insert(self, anItem):
''' Answer None if the BTree already contains a matching
item. If not, insert a deep copy of anItem and answer
anItem.
'''
searchResult = self.searchTree(anItem) #search for anItem
if searchResult['found']: #if anItem already exists in the tree, return None
return None
else: #if anItem doesn't exist in the tree
insertNode = self.readFrom(searchResult['fileIndex']) #get the node anItem should belong in
if insertNode.isFull(): #if the node is full, need to split the node
toParent = deepcopy(anItem) #make a deepcopy of the item we want to insert
leftChild = None #since inserting into a leaf node, left and right children are None
rightChild = None
while insertNode.isFull():
splitNode = insertNode.addItemAndSplit(toParent, leftChild, rightChild) #split the full node
splitNode.setIndex(self.freeIndex) #set the index of the new node to be the next available index
self.freeIndex += 1 #increment the free index number
toParent = deepcopy(insertNode.getItems()[insertNode.getNumberOfKeys()-1]) #get the item that will go to the parent node
insertNode.getItems()[insertNode.getNumberOfKeys()-1] = None #get rid of the record of the parent item
insertNode.getChild()[insertNode.getNumberOfKeys()] = None #get rid of the right child of the parent in the insertNode
insertNode.setNumberOfKeys(insertNode.getNumberOfKeys()-1)
leftChild = insertNode.getIndex() #get the left and right indices of the parent
rightChild = splitNode.getIndex()
self.writeAt(leftChild, insertNode) #write both nodes to the file
self.writeAt(rightChild, splitNode)
insertNode = self.stackOfNodes.pop() #get the parent node
if insertNode == None: #if there is no parent, create a new root node
insertNode = BTreeNode(self.degree) #create a new node
insertNode.setIndex(self.freeIndex) #set the index of the new root node
self.rootNode = insertNode
self.rootIndex = self.freeIndex #set the root index
self.freeIndex += 1 #increment the free index number
insertNode.insertItem(toParent, leftChild, rightChild)#if the parent node isn't full, just insert the item
self.writeAt(insertNode.getIndex(), insertNode) #write the final node to the file
else: #there is room for anItem, so just perform an insert
insertNode.insertItem(deepcopy(anItem))
self.writeAt(searchResult['fileIndex'], insertNode) #write the node to the file
return anItem #return the item
def insert(self, anItem):
''' Answer None if the BTree already contains a matching
item. If not, insert a deep copy of anItem and answer
anItem.
'''
searchResult = self.searchTree(anItem) #search for anItem
if searchResult[
'found']: #if anItem already exists in the tree, return None
return None
else: #if anItem doesn't exist in the tree
insertNode = self.readFrom(searchResult['fileIndex']
) #get the node anItem should belong in
if insertNode.isFull(
): #if the node is full, need to split the node
toParent = deepcopy(
anItem) #make a deepcopy of the item we want to insert
leftChild = None #since inserting into a leaf node, left and right children are None
rightChild = None
while insertNode.isFull():
splitNode = insertNode.addItemAndSplit(
toParent, leftChild, rightChild) #split the full node
splitNode.setIndex(
self.freeIndex
) #set the index of the new node to be the next available index
self.freeIndex += 1 #increment the free index number
toParent = deepcopy(insertNode.getItems()[
insertNode.getNumberOfKeys() -
1]) #get the item that will go to the parent node
insertNode.getItems()[
insertNode.getNumberOfKeys() -
1] = None #get rid of the record of the parent item
insertNode.getChild()[insertNode.getNumberOfKeys(
)] = None #get rid of the right child of the parent in the insertNode
insertNode.setNumberOfKeys(insertNode.getNumberOfKeys() -
1)
leftChild = insertNode.getIndex(
) #get the left and right indices of the parent
rightChild = splitNode.getIndex()
self.writeAt(leftChild,
insertNode) #write both nodes to the file
self.writeAt(rightChild, splitNode)
insertNode = self.stackOfNodes.pop() #get the parent node
if insertNode == None: #if there is no parent, create a new root node
insertNode = BTreeNode(self.degree) #create a new node
insertNode.setIndex(
self.freeIndex
) #set the index of the new root node
self.rootNode = insertNode
self.rootIndex = self.freeIndex #set the root index
self.freeIndex += 1 #increment the free index number
insertNode.insertItem(
toParent, leftChild, rightChild
) #if the parent node isn't full, just insert the item
self.writeAt(insertNode.getIndex(),
insertNode) #write the final node to the file
else: #there is room for anItem, so just perform an insert
insertNode.insertItem(deepcopy(anItem))
self.writeAt(searchResult['fileIndex'],
insertNode) #write the node to the file
return anItem #return the item
