net/quic/quic_bandwidth.cc

   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/quic_bandwidth.h"
   6
   7 #include "base/logging.h"
   8 #include "base/time/time.h"
   9
  10 namespace net {
  11
  12 // Highest number that QuicBandwidth can hold.
  13 const int64 kQuicInfiniteBandwidth = GG_INT64_C(0x7fffffffffffffff);
  14
  15 // static
  16 QuicBandwidth QuicBandwidth::Zero() {
  17   return QuicBandwidth(0);
  18 }
  19
  20 // static
  21 QuicBandwidth QuicBandwidth::FromBitsPerSecond(int64 bits_per_second) {
  22   return QuicBandwidth(bits_per_second);
  23 }
  24
  25 // static
  26 QuicBandwidth QuicBandwidth::FromKBitsPerSecond(int64 k_bits_per_second) {
  27   DCHECK(k_bits_per_second < kQuicInfiniteBandwidth / 1000);
  28   return QuicBandwidth(k_bits_per_second * 1000);
  29 }
  30
  31 // static
  32 QuicBandwidth QuicBandwidth::FromBytesPerSecond(int64 bytes_per_second) {
  33   DCHECK(bytes_per_second < kQuicInfiniteBandwidth / 8);
  34   return QuicBandwidth(bytes_per_second * 8);
  35 }
  36
  37 // static
  38 QuicBandwidth QuicBandwidth::FromKBytesPerSecond(int64 k_bytes_per_second) {
  39   DCHECK(k_bytes_per_second < kQuicInfiniteBandwidth / 8000);
  40   return QuicBandwidth(k_bytes_per_second * 8000);
  41 }
  42
  43 // static
  44 QuicBandwidth QuicBandwidth::FromBytesAndTimeDelta(QuicByteCount bytes,
  45                                                    QuicTime::Delta delta) {
  46   DCHECK_LT(bytes,
  47             static_cast<uint64>(kQuicInfiniteBandwidth /
  48                                 (8 * base::Time::kMicrosecondsPerSecond)));
  49   int64 bytes_per_second = (bytes * base::Time::kMicrosecondsPerSecond) /
  50       delta.ToMicroseconds();
  51   return QuicBandwidth(bytes_per_second * 8);
  52 }
  53
  54 QuicBandwidth::QuicBandwidth(int64 bits_per_second)
  55     : bits_per_second_(bits_per_second) {
  56   DCHECK_GE(bits_per_second, 0);
  57 }
  58
  59 int64 QuicBandwidth::ToBitsPerSecond() const {
  60   return bits_per_second_;
  61 }
  62
  63 int64 QuicBandwidth::ToKBitsPerSecond() const {
  64   return bits_per_second_ / 1000;
  65 }
  66
  67 int64 QuicBandwidth::ToBytesPerSecond() const {
  68   return bits_per_second_ / 8;
  69 }
  70
  71 int64 QuicBandwidth::ToKBytesPerSecond() const {
  72   return bits_per_second_ / 8000;
  73 }
  74
  75 QuicByteCount QuicBandwidth::ToBytesPerPeriod(
  76     QuicTime::Delta time_period) const {
  77   return ToBytesPerSecond() * time_period.ToMicroseconds() /
  78       base::Time::kMicrosecondsPerSecond;
  79 }
  80
  81 int64 QuicBandwidth::ToKBytesPerPeriod(QuicTime::Delta time_period) const {
  82   return ToKBytesPerSecond() * time_period.ToMicroseconds() /
  83       base::Time::kMicrosecondsPerSecond;
  84 }
  85
  86 bool QuicBandwidth::IsZero() const {
  87   return (bits_per_second_ == 0);
  88 }
  89
  90 QuicBandwidth QuicBandwidth::Add(const QuicBandwidth& delta) const {
  91   return QuicBandwidth(bits_per_second_ + delta.bits_per_second_);
  92 }
  93
  94 QuicBandwidth QuicBandwidth::Subtract(const QuicBandwidth& delta) const {
  95   return QuicBandwidth(bits_per_second_ - delta.bits_per_second_);
  96 }
  97
  98 QuicBandwidth QuicBandwidth::Scale(float scale_factor) const {
  99   return QuicBandwidth(static_cast<int64>(bits_per_second_ * scale_factor));
 100 }
 101
 102 QuicTime::Delta QuicBandwidth::TransferTime(QuicByteCount bytes) const {
 103   if (bits_per_second_ == 0) {
 104     return QuicTime::Delta::Zero();
 105   }
 106   return QuicTime::Delta::FromMicroseconds(
 107       bytes * 8 * base::Time::kMicrosecondsPerSecond / bits_per_second_);
 108 }
 109
 110 }  // namespace net