1 files changed, 52 insertions, 0 deletions
diff --git a/module/network/Bucket.py b/module/network/Bucket.py
new file mode 100644
index 000000000..408a1e240
--- /dev/null
+++ b/module/network/Bucket.py
@@ -0,0 +1,52 @@
+# -*- coding: utf-8 -*-
+# @author: RaNaN
+
+from time import time
+from threading import Lock
+
+MIN_RATE = 10240  #: 10kb minimum rate
+
+
+class Bucket(object):
+
+    def __init__(self):
+        self.rate      = 0 # bytes per second, maximum targeted throughput
+        self.tokens    = 0
+        self.timestamp = time()
+        self.lock      = Lock()
+
+
+    def __nonzero__(self):
+        return False if self.rate < MIN_RATE else True
+
+
+    def setRate(self, rate):
+        self.lock.acquire()
+        self.rate = int(rate)
+        self.lock.release()
+
+
+    def consumed(self, amount):
+        """ return the time the process has to sleep, after it consumed a specified amount """
+        if self.rate < MIN_RATE:
+            return 0  #: May become unresponsive otherwise
+
+        self.lock.acquire()
+        self.calc_tokens()
+        self.tokens -= amount
+
+        if self.tokens < 0:
+            time = -self.tokens/float(self.rate)
+        else:
+            time = 0
+
+        self.lock.release()
+        return time
+
+
+    def calc_tokens(self):
+        if self.tokens < self.rate:
+            now = time()
+            delta = self.rate * (now - self.timestamp)
+            self.tokens = min(self.rate, self.tokens + delta)
+            self.timestamp = now