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8fe7995045
This is useful for internal calculations in bitrate control code as we
can skip conversion constants.
DataRate Example(TimeDelta time, DataSize size) {
double time_seconds = time.seconds<double>();
double size_bytes = size.bytes<double>();
double rate_bytes_per_sec = size_bytes/time_seconds;
return DataRate::bytes_per_sec(std::max(0.0,rate_bytes_per_sec));
}
Bug: webrtc:9709
Change-Id: I8eefed578b6e8eee67fc36af723216407e0d0323
Reviewed-on: https://webrtc-review.googlesource.com/c/120720
Commit-Queue: Sebastian Jansson <srte@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26488}
121 lines
3.9 KiB
C++
121 lines
3.9 KiB
C++
/*
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* Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef API_UNITS_DATA_RATE_H_
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#define API_UNITS_DATA_RATE_H_
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#ifdef UNIT_TEST
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#include <ostream> // no-presubmit-check TODO(webrtc:8982)
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#endif // UNIT_TEST
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#include <limits>
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#include <string>
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#include <type_traits>
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#include "api/units/data_size.h"
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#include "api/units/time_delta.h"
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#include "rtc_base/checks.h"
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#include "rtc_base/units/unit_base.h"
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namespace webrtc {
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namespace data_rate_impl {
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inline int64_t Microbits(const DataSize& size) {
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constexpr int64_t kMaxBeforeConversion =
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std::numeric_limits<int64_t>::max() / 8000000;
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RTC_DCHECK_LE(size.bytes(), kMaxBeforeConversion)
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<< "size is too large to be expressed in microbytes";
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return size.bytes() * 8000000;
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}
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} // namespace data_rate_impl
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// DataRate is a class that represents a given data rate. This can be used to
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// represent bandwidth, encoding bitrate, etc. The internal storage is bits per
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// second (bps).
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class DataRate final : public rtc_units_impl::RelativeUnit<DataRate> {
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public:
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DataRate() = delete;
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static constexpr DataRate Infinity() { return PlusInfinity(); }
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template <int64_t bps>
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static constexpr DataRate BitsPerSec() {
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return FromStaticValue<bps>();
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}
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template <int64_t kbps>
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static constexpr DataRate KilobitsPerSec() {
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return FromStaticFraction<kbps, 1000>();
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}
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template <typename T>
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static constexpr DataRate bps(T bits_per_second) {
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static_assert(std::is_arithmetic<T>::value, "");
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return FromValue(bits_per_second);
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}
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template <typename T>
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static constexpr DataRate bytes_per_sec(T bytes_per_second) {
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static_assert(std::is_arithmetic<T>::value, "");
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return FromFraction<8>(bytes_per_second);
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}
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template <typename T>
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static constexpr DataRate kbps(T kilobits_per_sec) {
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static_assert(std::is_arithmetic<T>::value, "");
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return FromFraction<1000>(kilobits_per_sec);
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}
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template <typename T = int64_t>
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constexpr T bps() const {
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return ToValue<T>();
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}
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template <typename T = int64_t>
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constexpr T bytes_per_sec() const {
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return ToFraction<8, T>();
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}
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template <typename T = int64_t>
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T kbps() const {
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return ToFraction<1000, T>();
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}
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constexpr int64_t bps_or(int64_t fallback_value) const {
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return ToValueOr(fallback_value);
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}
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constexpr int64_t kbps_or(int64_t fallback_value) const {
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return ToFractionOr<1000>(fallback_value);
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}
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private:
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// Bits per second used internally to simplify debugging by making the value
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// more recognizable.
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friend class rtc_units_impl::UnitBase<DataRate>;
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using RelativeUnit::RelativeUnit;
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static constexpr bool one_sided = true;
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};
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inline DataRate operator/(const DataSize size, const TimeDelta duration) {
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return DataRate::bps(data_rate_impl::Microbits(size) / duration.us());
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}
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inline TimeDelta operator/(const DataSize size, const DataRate rate) {
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return TimeDelta::us(data_rate_impl::Microbits(size) / rate.bps());
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}
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inline DataSize operator*(const DataRate rate, const TimeDelta duration) {
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int64_t microbits = rate.bps() * duration.us();
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return DataSize::bytes((microbits + 4000000) / 8000000);
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}
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inline DataSize operator*(const TimeDelta duration, const DataRate rate) {
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return rate * duration;
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}
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std::string ToString(DataRate value);
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#ifdef UNIT_TEST
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inline std::ostream& operator<<( // no-presubmit-check TODO(webrtc:8982)
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std::ostream& stream, // no-presubmit-check TODO(webrtc:8982)
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DataRate value) {
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return stream << ToString(value);
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}
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#endif // UNIT_TEST
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} // namespace webrtc
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#endif // API_UNITS_DATA_RATE_H_
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