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/*
* Copyright (c) 2016 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.
*/
#include "modules/pacing/interval_budget.h"
#include <algorithm>
#include <cstddef>
#include <cstdint>
#include "rtc_base/numerics/safe_conversions.h"
namespace webrtc {
namespace {
constexpr int64_t kWindowMs = 500;
}
IntervalBudget::IntervalBudget(int initial_target_rate_kbps)
: IntervalBudget(initial_target_rate_kbps, false) {}
IntervalBudget::IntervalBudget(int initial_target_rate_kbps,
bool can_build_up_underuse)
: bytes_remaining_(0), can_build_up_underuse_(can_build_up_underuse) {
set_target_rate_kbps(initial_target_rate_kbps);
}
void IntervalBudget::set_target_rate_kbps(int target_rate_kbps) {
target_rate_kbps_ = target_rate_kbps;
max_bytes_in_budget_ = (kWindowMs * target_rate_kbps_) / 8;
bytes_remaining_ = std::min(std::max(-max_bytes_in_budget_, bytes_remaining_),
max_bytes_in_budget_);
}
void IntervalBudget::IncreaseBudget(int64_t delta_time_ms) {
int64_t bytes = target_rate_kbps_ * delta_time_ms / 8;
if (bytes_remaining_ < 0 || can_build_up_underuse_) {
// We overused last interval, compensate this interval.
bytes_remaining_ = std::min(bytes_remaining_ + bytes, max_bytes_in_budget_);
} else {
// If we underused last interval we can't use it this interval.
bytes_remaining_ = std::min(bytes, max_bytes_in_budget_);
}
}
void IntervalBudget::UseBudget(size_t bytes) {
bytes_remaining_ = std::max(bytes_remaining_ - static_cast<int>(bytes),
-max_bytes_in_budget_);
}
size_t IntervalBudget::bytes_remaining() const {
return rtc::saturated_cast<size_t>(std::max<int64_t>(0, bytes_remaining_));
}
double IntervalBudget::budget_ratio() const {
if (max_bytes_in_budget_ == 0)
return 0.0;
return static_cast<double>(bytes_remaining_) / max_bytes_in_budget_;
}
int IntervalBudget::target_rate_kbps() const {
return target_rate_kbps_;
}
} // namespace webrtc