net/quic/congestion_control/leaky_bucket.h

   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
  19 namespace net {
  20
  21 class 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_