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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// QuicBandwidth represents a bandwidth, stored in bits per second resolution.
#ifndef QUICHE_QUIC_CORE_QUIC_BANDWIDTH_H_
#define QUICHE_QUIC_CORE_QUIC_BANDWIDTH_H_
#include <cmath>
#include <cstdint>
#include <limits>
#include <ostream>
#include <string>
#include "quiche/quic/core/quic_constants.h"
#include "quiche/quic/core/quic_time.h"
#include "quiche/quic/core/quic_types.h"
#include "quiche/quic/platform/api/quic_export.h"
#include "quiche/quic/platform/api/quic_flag_utils.h"
namespace quic {
class QUICHE_EXPORT QuicBandwidth {
public:
// Creates a new QuicBandwidth with an internal value of 0.
static constexpr QuicBandwidth Zero() { return QuicBandwidth(0); }
// Creates a new QuicBandwidth with an internal value of INT64_MAX.
static constexpr QuicBandwidth Infinite() {
return QuicBandwidth(std::numeric_limits<int64_t>::max());
}
// Create a new QuicBandwidth holding the bits per second.
static constexpr QuicBandwidth FromBitsPerSecond(int64_t bits_per_second) {
return QuicBandwidth(bits_per_second);
}
// Create a new QuicBandwidth holding the kilo bits per second.
static constexpr QuicBandwidth FromKBitsPerSecond(int64_t k_bits_per_second) {
return QuicBandwidth(k_bits_per_second * 1000);
}
// Create a new QuicBandwidth holding the bytes per second.
static constexpr QuicBandwidth FromBytesPerSecond(int64_t bytes_per_second) {
return QuicBandwidth(bytes_per_second * 8);
}
// Create a new QuicBandwidth holding the kilo bytes per second.
static constexpr QuicBandwidth FromKBytesPerSecond(
int64_t k_bytes_per_second) {
return QuicBandwidth(k_bytes_per_second * 8000);
}
// Create a new QuicBandwidth based on the bytes per the elapsed delta.
static QuicBandwidth FromBytesAndTimeDelta(QuicByteCount bytes,
QuicTime::Delta delta) {
if (bytes == 0) {
return QuicBandwidth(0);
}
// 1 bit is 1000000 micro bits.
int64_t num_micro_bits = 8 * bytes * kNumMicrosPerSecond;
if (num_micro_bits < delta.ToMicroseconds()) {
return QuicBandwidth(1);
}
return QuicBandwidth(num_micro_bits / delta.ToMicroseconds());
}
int64_t ToBitsPerSecond() const { return bits_per_second_; }
int64_t ToKBitsPerSecond() const { return bits_per_second_ / 1000; }
int64_t ToBytesPerSecond() const { return bits_per_second_ / 8; }
int64_t ToKBytesPerSecond() const { return bits_per_second_ / 8000; }
constexpr QuicByteCount ToBytesPerPeriod(QuicTime::Delta time_period) const {
return bits_per_second_ * time_period.ToMicroseconds() / 8 /
kNumMicrosPerSecond;
}
int64_t ToKBytesPerPeriod(QuicTime::Delta time_period) const {
return bits_per_second_ * time_period.ToMicroseconds() / 8000 /
kNumMicrosPerSecond;
}
bool IsZero() const { return bits_per_second_ == 0; }
bool IsInfinite() const {
return bits_per_second_ == Infinite().ToBitsPerSecond();
}
constexpr QuicTime::Delta TransferTime(QuicByteCount bytes) const {
if (bits_per_second_ == 0) {
return QuicTime::Delta::Zero();
}
return QuicTime::Delta::FromMicroseconds(bytes * 8 * kNumMicrosPerSecond /
bits_per_second_);
}
std::string ToDebuggingValue() const;
private:
explicit constexpr QuicBandwidth(int64_t bits_per_second)
: bits_per_second_(bits_per_second >= 0 ? bits_per_second : 0) {}
int64_t bits_per_second_;
friend constexpr QuicBandwidth operator+(QuicBandwidth lhs,
QuicBandwidth rhs);
friend constexpr QuicBandwidth operator-(QuicBandwidth lhs,
QuicBandwidth rhs);
friend QuicBandwidth operator*(QuicBandwidth lhs, float rhs);
};
// Non-member relational operators for QuicBandwidth.
inline bool operator==(QuicBandwidth lhs, QuicBandwidth rhs) {
return lhs.ToBitsPerSecond() == rhs.ToBitsPerSecond();
}
inline bool operator!=(QuicBandwidth lhs, QuicBandwidth rhs) {
return !(lhs == rhs);
}
inline bool operator<(QuicBandwidth lhs, QuicBandwidth rhs) {
return lhs.ToBitsPerSecond() < rhs.ToBitsPerSecond();
}
inline bool operator>(QuicBandwidth lhs, QuicBandwidth rhs) {
return rhs < lhs;
}
inline bool operator<=(QuicBandwidth lhs, QuicBandwidth rhs) {
return !(rhs < lhs);
}
inline bool operator>=(QuicBandwidth lhs, QuicBandwidth rhs) {
return !(lhs < rhs);
}
// Non-member arithmetic operators for QuicBandwidth.
inline constexpr QuicBandwidth operator+(QuicBandwidth lhs, QuicBandwidth rhs) {
return QuicBandwidth(lhs.bits_per_second_ + rhs.bits_per_second_);
}
inline constexpr QuicBandwidth operator-(QuicBandwidth lhs, QuicBandwidth rhs) {
return QuicBandwidth(lhs.bits_per_second_ - rhs.bits_per_second_);
}
inline QuicBandwidth operator*(QuicBandwidth lhs, float rhs) {
return QuicBandwidth(
static_cast<int64_t>(std::llround(lhs.bits_per_second_ * rhs)));
}
inline QuicBandwidth operator*(float lhs, QuicBandwidth rhs) {
return rhs * lhs;
}
inline constexpr QuicByteCount operator*(QuicBandwidth lhs,
QuicTime::Delta rhs) {
return lhs.ToBytesPerPeriod(rhs);
}
inline constexpr QuicByteCount operator*(QuicTime::Delta lhs,
QuicBandwidth rhs) {
return rhs * lhs;
}
// Override stream output operator for gtest.
inline std::ostream& operator<<(std::ostream& output,
const QuicBandwidth bandwidth) {
output << bandwidth.ToDebuggingValue();
return output;
}
} // namespace quic
#endif // QUICHE_QUIC_CORE_QUIC_BANDWIDTH_H_