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#include "net/quic/congestion_control/leaky_bucket.h"
6
7#include "base/time/time.h"
8
9namespace net {
10
11LeakyBucket::LeakyBucket(QuicBandwidth draining_rate)
12    : bytes_(0),
13      time_last_updated_(QuicTime::Zero()),
14      draining_rate_(draining_rate) {
15}
16
17void LeakyBucket::SetDrainingRate(QuicTime now, QuicBandwidth draining_rate) {
18  Update(now);
19  draining_rate_ = draining_rate;
20}
21
22void LeakyBucket::Add(QuicTime now, QuicByteCount bytes) {
23  Update(now);
24  bytes_ += bytes;
25}
26
27QuicTime::Delta LeakyBucket::TimeRemaining(QuicTime now) {
28  Update(now);
29  return QuicTime::Delta::FromMicroseconds(
30      (bytes_ * base::Time::kMicrosecondsPerSecond) /
31      draining_rate_.ToBytesPerSecond());
32}
33
34QuicByteCount LeakyBucket::BytesPending(QuicTime now) {
35  Update(now);
36  return bytes_;
37}
38
39void LeakyBucket::Update(QuicTime now) {
40  QuicTime::Delta elapsed_time = now.Subtract(time_last_updated_);
41  QuicByteCount bytes_cleared = draining_rate_.ToBytesPerPeriod(elapsed_time);
42  if (bytes_cleared >= bytes_) {
43    bytes_ = 0;
44  } else {
45    bytes_ -= bytes_cleared;
46  }
47  time_last_updated_ = now;
48}
49
50}  // namespace net
51