Rename media::Clock to media::TimeDeltaInterpolator and update API.

media/base/clock.cc

-// 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),
-      playing_(false),
-      underflow_(false),
-      playback_rate_(1.0f),
-      max_time_(kNoTimestamp()) {
-  DCHECK(clock_);
-}
-
-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() {
-  // 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_;
-}
-
-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 {
-  return std::max(base::TimeDelta(), time);
-}
-
-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()));
-}
-
-}  // namespace media