1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4//
5// Helper class to track the rate data can leave the buffer for pacing.
6// A leaky bucket drains the data at a constant rate regardless of fullness of
7// the buffer.
8// See http://en.wikipedia.org/wiki/Leaky_bucket for more details.
9
10#ifndef NET_QUIC_CONGESTION_CONTROL_LEAKY_BUCKET_H_
11#define NET_QUIC_CONGESTION_CONTROL_LEAKY_BUCKET_H_
12
13#include "base/basictypes.h"
14#include "net/base/net_export.h"
15#include "net/quic/quic_bandwidth.h"
16#include "net/quic/quic_protocol.h"
17#include "net/quic/quic_time.h"
18
19namespace net {
20
21class NET_EXPORT_PRIVATE LeakyBucket {
22 public:
23  explicit LeakyBucket(QuicBandwidth draining_rate);
24
25  // Set the rate at which the bytes leave the buffer.
26  void SetDrainingRate(QuicTime now, QuicBandwidth draining_rate);
27
28  // Add data to the buffer.
29  void Add(QuicTime now, QuicByteCount bytes);
30
31  // Time until the buffer is empty.
32  QuicTime::Delta TimeRemaining(QuicTime now) const;
33
34  // Number of bytes in the buffer.
35  QuicByteCount BytesPending(QuicTime now);
36
37 private:
38  void Update(QuicTime now);
39
40  QuicByteCount bytes_;
41  QuicTime time_last_updated_;
42  QuicBandwidth draining_rate_;
43
44  DISALLOW_COPY_AND_ASSIGN(LeakyBucket);
45};
46
47}  // namespace net
48
49#endif  // NET_QUIC_CONGESTION_CONTROL_LEAKY_BUCKET_H_
50