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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.
#include "media/base/clock.h"
#include <algorithm>
#include "base/logging.h"
#include "base/time/tick_clock.h"
#include "media/base/buffers.h"
namespace media {
Clock::Clock(base::TickClock* clock) : clock_(clock) {
DCHECK(clock_);
Reset();
}
Clock::~Clock() {}
bool Clock::IsPlaying() const {
return playing_;
}
base::TimeDelta Clock::Play() {
DCHECK(!playing_);
UpdateReferencePoints();
playing_ = true;
return media_time_;
}
base::TimeDelta Clock::Pause() {
DCHECK(playing_);
UpdateReferencePoints();
playing_ = false;
return media_time_;
}
void Clock::SetPlaybackRate(float playback_rate) {
UpdateReferencePoints();
playback_rate_ = playback_rate;
}
void Clock::SetTime(base::TimeDelta current_time, base::TimeDelta max_time) {
DCHECK(current_time <= max_time);
DCHECK(current_time != kNoTimestamp());
UpdateReferencePoints(current_time);
max_time_ = ClampToValidTimeRange(max_time);
underflow_ = false;
}
base::TimeDelta Clock::Elapsed() {
if (duration_ == kNoTimestamp())
return base::TimeDelta();
// The clock is not advancing, so return the last recorded time.
if (!playing_ || underflow_)
return media_time_;
base::TimeDelta elapsed = EstimatedElapsedTime();
if (max_time_ != kNoTimestamp() && elapsed > max_time_) {
UpdateReferencePoints(max_time_);
underflow_ = true;
elapsed = max_time_;
}
return elapsed;
}
void Clock::SetMaxTime(base::TimeDelta max_time) {
DCHECK(max_time != kNoTimestamp());
UpdateReferencePoints();
max_time_ = ClampToValidTimeRange(max_time);
underflow_ = media_time_ > max_time_;
if (underflow_)
media_time_ = max_time_;
}
void Clock::SetDuration(base::TimeDelta duration) {
DCHECK(duration > base::TimeDelta());
duration_ = duration;
media_time_ = ClampToValidTimeRange(media_time_);
if (max_time_ != kNoTimestamp())
max_time_ = ClampToValidTimeRange(max_time_);
}
base::TimeDelta Clock::ElapsedViaProvidedTime(
const base::TimeTicks& time) const {
// TODO(scherkus): floating point badness scaling time by playback rate.
int64 now_us = (time - reference_).InMicroseconds();
now_us = static_cast<int64>(now_us * playback_rate_);
return media_time_ + base::TimeDelta::FromMicroseconds(now_us);
}
base::TimeDelta Clock::ClampToValidTimeRange(base::TimeDelta time) const {
if (duration_ == kNoTimestamp())
return base::TimeDelta();
return std::max(std::min(time, duration_), base::TimeDelta());
}
void Clock::EndOfStream() {
Pause();
SetTime(Duration(), Duration());
}
base::TimeDelta Clock::Duration() const {
if (duration_ == kNoTimestamp())
return base::TimeDelta();
return duration_;
}
void Clock::UpdateReferencePoints() {
UpdateReferencePoints(Elapsed());
}
void Clock::UpdateReferencePoints(base::TimeDelta current_time) {
media_time_ = ClampToValidTimeRange(current_time);
reference_ = clock_->NowTicks();
}
base::TimeDelta Clock::EstimatedElapsedTime() {
return ClampToValidTimeRange(ElapsedViaProvidedTime(clock_->NowTicks()));
}
void Clock::Reset() {
playing_ = false;
playback_rate_ = 1.0f;
max_time_ = kNoTimestamp();
duration_ = kNoTimestamp();
media_time_ = base::TimeDelta();
reference_ = base::TimeTicks();
underflow_ = false;
}
} // namespace media
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