def range_compressed_MAC(self, rmin, rmax, include_rmin=True, include_rmax=True):
"""Get compressed MAC for a range, verifying elements past the
end of range."""
if not self.root:
return setmac.empty_compressed_MAC
m_all = setmac.extract_compressed_MAC(self.key1, self.root.mac)
if rmin:
m_left = setmac.empty_compressed_MAC
# invariant: after each iteration we still need to search
# in t for the least value satisfying rmin constraint
t = self.root
while t:
t.verify()
if t.row_key < rmin or (t.row_key == rmin and not include_rmin):
# neither t nor t.left need to be included in the
# results, min satisfying is in t.right
t = t.right
else:
# t and t.right needs to be included in the
# results. min satisfying is in t.left
m_left = setmac.xor_hashes(m_left, setmac.extract_compressed_MAC(self.key1, t.mac))
if t.left:
m_left = setmac.xor_hashes(m_left, setmac.extract_compressed_MAC(self.key1, t.left.mac))
t = t.left
else:
m_left = m_all
if rmax:
m_right = setmac.empty_compressed_MAC
# invariant: after each iteration we still need to search
# in t for the greatest value satisfying rmax constraint
t = self.root
while t:
t.verify()
if t.row_key > rmax or (t.row_key == rmax and not include_rmax):
# neither t nor t.right need to be included in the
# results, max satisfying is in t.left
t = t.left
else:
# t and t.left needs to be included in the
# results. max satisfying is in t.right
m_right = setmac.xor_hashes(m_right, setmac.extract_compressed_MAC(self.key1, t.mac))
if t.right:
m_right = setmac.xor_hashes(m_right, setmac.extract_compressed_MAC(self.key1, t.right.mac))
t = t.right
else:
m_right = m_all
return setmac.xor_hashes(m_all, setmac.xor_hashes(m_left, m_right))
def verify(self):
"""Verifies that the MAC stored in this node is correct,
assuming that left/right have correct MACs; also verifies the
BST property."""
mac = setmac.compress(self.tree.key2, {self.value: self.row_key})
if self.left:
assert(self.left.key < self.key)
mac = setmac.xor_hashes(mac, setmac.extract_compressed_MAC(self.tree.key1, self.left.mac))
if self.right:
assert(not (self.right.key < self.key))
mac = setmac.xor_hashes(mac, setmac.extract_compressed_MAC(self.tree.key1, self.right.mac))
assert(setmac.extract_compressed_MAC(self.tree.key1, self.mac) == mac)
def update_hook(self):
"""Rehashes child nodes."""
mac = setmac.compress(self.tree.key2, {self.value: self.row_key})
if self.left:
mac = setmac.xor_hashes(mac, setmac.extract_compressed_MAC(self.tree.key1, self.left.mac))
if self.right:
mac = setmac.xor_hashes(mac, setmac.extract_compressed_MAC(self.tree.key1, self.right.mac))
self.mac = setmac.encrypt_compressed_MAC(self.tree.key1, mac)
left_id = self.left_id if self.left_id else -1
right_id = self.right_id if self.right_id else -1
c = self.tree.local_conn.cursor()
c.execute("UPDATE %s SET left = ?, right = ?, mac = ? WHERE row_id = ?" % self.tree.table_name,
(left_id, right_id,
setmac.marshall_MAC(self.mac), self.value))
self.tree.conn.commit()
#self.tree.transaction.commit_unless_managed()
c.close()
