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 <stdint.h>
   8
   9 #include "base/logging.h"
  10 #include "net/quic/quic_time.h"
  11 #include "net/quic/quic_types.h"
  12
  13 namespace net {
  14
  15 // Highest number that QuicBandwidth can hold.
  16 const int64 kQuicInfiniteBandwidth = INT64_C(0x7fffffffffffffff);
  17
  18 // static
  19 QuicBandwidth QuicBandwidth::Zero() {
  20   return QuicBandwidth(0);
  21 }
  22
  23 // static
  24 QuicBandwidth QuicBandwidth::FromBitsPerSecond(int64 bits_per_second) {
  25   return QuicBandwidth(bits_per_second);
  26 }
  27
  28 // static
  29 QuicBandwidth QuicBandwidth::FromKBitsPerSecond(int64 k_bits_per_second) {
  30   DCHECK(k_bits_per_second < kQuicInfiniteBandwidth / 1000);
  31   return QuicBandwidth(k_bits_per_second * 1000);
  32 }
  33
  34 // static
  35 QuicBandwidth QuicBandwidth::FromBytesPerSecond(int64 bytes_per_second) {
  36   DCHECK(bytes_per_second < kQuicInfiniteBandwidth / 8);
  37   return QuicBandwidth(bytes_per_second * 8);
  38 }
  39
  40 // static
  41 QuicBandwidth QuicBandwidth::FromKBytesPerSecond(int64 k_bytes_per_second) {
  42   DCHECK(k_bytes_per_second < kQuicInfiniteBandwidth / 8000);
  43   return QuicBandwidth(k_bytes_per_second * 8000);
  44 }
  45
  46 // static
  47 QuicBandwidth QuicBandwidth::FromBytesAndTimeDelta(QuicByteCount bytes,
  48                                                    QuicTime::Delta delta) {
  49   DCHECK_LT(bytes, static_cast<uint64>(kQuicInfiniteBandwidth /
  50                                        (8 * kNumMicrosPerSecond)));
  51   int64 bytes_per_second =
  52       (bytes * kNumMicrosPerSecond) / delta.ToMicroseconds();
  53   return QuicBandwidth(bytes_per_second * 8);
  54 }
  55
  56 QuicBandwidth::QuicBandwidth(int64 bits_per_second)
  57     : bits_per_second_(bits_per_second) {
  58   DCHECK_GE(bits_per_second, 0);
  59 }
  60
  61 int64 QuicBandwidth::ToBitsPerSecond() const {
  62   return bits_per_second_;
  63 }
  64
  65 int64 QuicBandwidth::ToKBitsPerSecond() const {
  66   return bits_per_second_ / 1000;
  67 }
  68
  69 int64 QuicBandwidth::ToBytesPerSecond() const {
  70   return bits_per_second_ / 8;
  71 }
  72
  73 int64 QuicBandwidth::ToKBytesPerSecond() const {
  74   return bits_per_second_ / 8000;
  75 }
  76
  77 QuicByteCount QuicBandwidth::ToBytesPerPeriod(
  78     QuicTime::Delta time_period) const {
  79   return ToBytesPerSecond() * time_period.ToMicroseconds() /
  80          kNumMicrosPerSecond;
  81 }
  82
  83 int64 QuicBandwidth::ToKBytesPerPeriod(QuicTime::Delta time_period) const {
  84   return ToKBytesPerSecond() * time_period.ToMicroseconds() /
  85          kNumMicrosPerSecond;
  86 }
  87
  88 bool QuicBandwidth::IsZero() const {
  89   return (bits_per_second_ == 0);
  90 }
  91
  92 QuicBandwidth QuicBandwidth::Add(const QuicBandwidth& delta) const {
  93   return QuicBandwidth(bits_per_second_ + delta.bits_per_second_);
  94 }
  95
  96 QuicBandwidth QuicBandwidth::Subtract(const QuicBandwidth& delta) const {
  97   return QuicBandwidth(bits_per_second_ - delta.bits_per_second_);
  98 }
  99
 100 QuicBandwidth QuicBandwidth::Scale(float scale_factor) const {
 101   return QuicBandwidth(static_cast<int64>(bits_per_second_ * scale_factor));
 102 }
 103
 104 QuicTime::Delta QuicBandwidth::TransferTime(QuicByteCount bytes) const {
 105   if (bits_per_second_ == 0) {
 106     return QuicTime::Delta::Zero();
 107   }
 108   return QuicTime::Delta::FromMicroseconds(bytes * 8 * kNumMicrosPerSecond /
 109                                            bits_per_second_);
 110 }
 111
 112 }  // namespace net