def _split_bucket(self, old_bucket_index):
"""
Splits the specified bucket into two new buckets which together
cover the same range in the key/ID space.
"""
# Resize the range of the current (old) bucket.
old_bucket = self._buckets[old_bucket_index]
split_point = old_bucket.range_max - (
old_bucket.range_max - old_bucket.range_min) / 2
# Create a new bucket to cover the range split off from the old
# bucket.
new_bucket = Bucket(split_point, old_bucket.range_max)
old_bucket.range_max = split_point
# Now, add the new bucket into the routing table.
self._buckets.insert(old_bucket_index + 1, new_bucket)
# Finally, copy all nodes that belong to the new bucket into it...
for contact in old_bucket._contacts:
if new_bucket.key_in_range(contact.network_id):
new_bucket.add_contact(contact)
# ...and remove them from the old bucket
for contact in new_bucket._contacts:
old_bucket.remove_contact(contact)
