foundationdb/layers/containers/treap.py

121 lines
3.7 KiB
Python

#
# treap.py
#
# This source file is part of the FoundationDB open source project
#
# Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
import fdb
import random
fdb.init("10.0.1.22:1234")
db = fdb.create_cluster("10.0.3.1:2181/evan_local").open_database("set")
class FdbTreap (object):
def __init__(self, path):
self._rootKey = path
self._path = path + '\x00'
@fdb.transactional
def updateNode(self, tr, node):
tr[fdb.tuple_to_key(self._path, node[0])] = fdb.tuple_to_key(node[1])
@fdb.transactional
def updateRoot(self, tr, node):
tr[self._rootKey] = fdb.tuple_to_key(self._path, node[0])
@fdb.transactional
def parent(self, tr, key):
# find parent
for k, v in tr.get_range(fdb.last_less_than(fdb.tuple_to_key(self._path, key)),
fdb.first_greater_than(fdb.tuple_to_key(self._path, key)) + 1, 2):
parentValue = fdb.key_to_tuple(v)
if parentValue[0] == key or parentValue[1] == key:
return tuple(fdb.key_to_tuple(k)[1], parentValue)
return None
@fdb.transactional
def balance(self, tr, parent, child):
if parent[1][2] >= child[1][2]:
return
grandparent = self.parent(tr, parent[0])
if grandparent == None:
self.updateRoot(tr, child)
elif grandparent[1][0] == parent[0]:
grandparent[1][0] = child[0]
self.updateNode(tr, grandparent)
else:
grandparent[1][1] = child[0]
self.updateNode(tr, grandparent)
if parent[1][0] == child[0]:
parent[1][0] = child[1][1]
child[1][1] = parent[0]
else:
parent[1][1] = child[1][0]
child[1][0] = parent[0]
self.updateNode(tr, parent)
self.updateNode(tr, child)
self.balance(tr, grandparent, child)
@fdb.transactional
def setKey(self, tr, key, value, metric):
isNew = True
isRoot = True
child = tuple(key, tuple("", "", random.random(), metric, value))
parent = tuple()
# find self or parent
for k, v in tr.get_range(fdb.last_less_than(fdb.tuple_to_key(self._path, key)),
fdb.first_greater_than(fdb.tuple_to_key(self._path, key)) + 1, 2):
isRoot = False
node = tuple(fdb.key_to_tuple(k)[1], fdb.key_to_tuple(v))
if node[0] == key:
isNew = False
child = node
node[1][4] = value
break
elif node[0] < key and node[1][1] == "":
isRoot = False
parent = node
parent[1][1] = key
break
elif node[0] > key and node[1][0] == "":
isRoot = False
parent = node
parent[1][0] = key
break
# insert root
if isRoot:
self.updateRoot(tr, child)
# update parent
if isNew:
self.updateNode(tr, parent)
# insert self
self.updateNode(tr, child)
# balance
self.balance(tr, parent, child)