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/*
* Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef API_UNITS_DATA_RATE_H_
#define API_UNITS_DATA_RATE_H_
#ifdef UNIT_TEST
#include <ostream> // no-presubmit-check TODO(webrtc:8982)
#endif // UNIT_TEST
#include <limits>
#include <string>
#include <type_traits>
#include "api/units/data_size.h"
#include "api/units/time_delta.h"
#include "rtc_base/checks.h"
#include "rtc_base/units/unit_base.h"
namespace webrtc {
namespace data_rate_impl {
inline int64_t Microbits(const DataSize& size) {
constexpr int64_t kMaxBeforeConversion =
std::numeric_limits<int64_t>::max() / 8000000;
RTC_DCHECK_LE(size.bytes(), kMaxBeforeConversion)
<< "size is too large to be expressed in microbytes";
return size.bytes() * 8000000;
}
} // namespace data_rate_impl
// DataRate is a class that represents a given data rate. This can be used to
// represent bandwidth, encoding bitrate, etc. The internal storage is bits per
// second (bps).
class DataRate final : public rtc_units_impl::RelativeUnit<DataRate> {
public:
DataRate() = delete;
static constexpr DataRate Infinity() { return PlusInfinity(); }
template <int64_t bps>
static constexpr DataRate BitsPerSec() {
return FromStaticValue<bps>();
}
template <int64_t kbps>
static constexpr DataRate KilobitsPerSec() {
return FromStaticFraction<kbps, 1000>();
}
template <typename T>
static constexpr DataRate bps(T bits_per_second) {
static_assert(std::is_arithmetic<T>::value, "");
return FromValue(bits_per_second);
}
template <typename T>
static constexpr DataRate bytes_per_sec(T bytes_per_second) {
static_assert(std::is_arithmetic<T>::value, "");
return FromFraction<8>(bytes_per_second);
}
template <typename T>
static constexpr DataRate kbps(T kilobits_per_sec) {
static_assert(std::is_arithmetic<T>::value, "");
return FromFraction<1000>(kilobits_per_sec);
}
template <typename T = int64_t>
constexpr T bps() const {
return ToValue<T>();
}
template <typename T = int64_t>
constexpr T bytes_per_sec() const {
return ToFraction<8, T>();
}
template <typename T = int64_t>
T kbps() const {
return ToFraction<1000, T>();
}
constexpr int64_t bps_or(int64_t fallback_value) const {
return ToValueOr(fallback_value);
}
constexpr int64_t kbps_or(int64_t fallback_value) const {
return ToFractionOr<1000>(fallback_value);
}
private:
// Bits per second used internally to simplify debugging by making the value
// more recognizable.
friend class rtc_units_impl::UnitBase<DataRate>;
using RelativeUnit::RelativeUnit;
static constexpr bool one_sided = true;
};
inline DataRate operator/(const DataSize size, const TimeDelta duration) {
return DataRate::bps(data_rate_impl::Microbits(size) / duration.us());
}
inline TimeDelta operator/(const DataSize size, const DataRate rate) {
return TimeDelta::us(data_rate_impl::Microbits(size) / rate.bps());
}
inline DataSize operator*(const DataRate rate, const TimeDelta duration) {
int64_t microbits = rate.bps() * duration.us();
return DataSize::bytes((microbits + 4000000) / 8000000);
}
inline DataSize operator*(const TimeDelta duration, const DataRate rate) {
return rate * duration;
}
std::string ToString(DataRate value);
#ifdef UNIT_TEST
inline std::ostream& operator<<( // no-presubmit-check TODO(webrtc:8982)
std::ostream& stream, // no-presubmit-check TODO(webrtc:8982)
DataRate value) {
return stream << ToString(value);
}
#endif // UNIT_TEST
} // namespace webrtc
#endif // API_UNITS_DATA_RATE_H_