Source/WebCore/Modules/mediasource/SampleMap.cpp - WebKit - Git at Google

 /*
  * Copyright (C) 2013 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  * THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include "config.h"
 #include "SampleMap.h"

 #include "MediaSample.h"

 namespace WebCore {

 template <typename M>
 class SampleIsLessThanMediaTimeComparator {
 public:
     typedef typename M::value_type value_type;
     bool operator()(const value_type& value, const MediaTime& time)
     {
         MediaTime presentationEndTime = value.second->presentationTime() + value.second->duration();
         return presentationEndTime <= time;
     }
     bool operator()(const MediaTime& time, const value_type& value)
     {
         MediaTime presentationStartTime = value.second->presentationTime();
         return time < presentationStartTime;
     }
 };

 template <typename M>
 class SampleIsGreaterThanMediaTimeComparator {
 public:
     typedef typename M::value_type value_type;
     bool operator()(const value_type& value, const MediaTime& time)
     {
         MediaTime presentationStartTime = value.second->presentationTime();
         return presentationStartTime > time;
     }
     bool operator()(const MediaTime& time, const value_type& value)
     {
         MediaTime presentationEndTime = value.second->presentationTime() + value.second->duration();
         return time >= presentationEndTime;
     }
 };

 class SampleIsRandomAccess {
 public:
     bool operator()(DecodeOrderSampleMap::MapType::value_type& value)
     {
         return value.second->flags() == MediaSample::IsSync;
     }
 };

 // SamplePresentationTimeIsInsideRangeComparator matches (range.first, range.second]
 struct SamplePresentationTimeIsInsideRangeComparator {
     bool operator()(std::pair<MediaTime, MediaTime> range, const std::pair<MediaTime, RefPtr<MediaSample>>& value)
     {
         return range.second < value.first;
     }
     bool operator()(const std::pair<MediaTime, RefPtr<MediaSample>>& value, std::pair<MediaTime, MediaTime> range)
     {
         return value.first <= range.first;
     }
 };

 // SamplePresentationTimeIsWithinRangeComparator matches [range.first, range.second)
 struct SamplePresentationTimeIsWithinRangeComparator {
     bool operator()(std::pair<MediaTime, MediaTime> range, const std::pair<MediaTime, RefPtr<MediaSample>>& value)
     {
         return range.second <= value.first;
     }
     bool operator()(const std::pair<MediaTime, RefPtr<MediaSample>>& value, std::pair<MediaTime, MediaTime> range)
     {
         return value.first < range.first;
     }
 };

 bool SampleMap::empty() const
 {
     return presentationOrder().m_samples.empty();
 }

 void SampleMap::clear()
 {
     presentationOrder().m_samples.clear();
     decodeOrder().m_samples.clear();
     m_totalSize = 0;
 }

 void SampleMap::addSample(MediaSample& sample)
 {
     MediaTime presentationTime = sample.presentationTime();

     presentationOrder().m_samples.insert(PresentationOrderSampleMap::MapType::value_type(presentationTime, &sample));

     auto decodeKey = DecodeOrderSampleMap::KeyType(sample.decodeTime(), presentationTime);
     decodeOrder().m_samples.insert(DecodeOrderSampleMap::MapType::value_type(decodeKey, &sample));

     m_totalSize += sample.sizeInBytes();
 }

 void SampleMap::removeSample(MediaSample* sample)
 {
     ASSERT(sample);
     MediaTime presentationTime = sample->presentationTime();

     m_totalSize -= sample->sizeInBytes();

     auto decodeKey = DecodeOrderSampleMap::KeyType(sample->decodeTime(), presentationTime);
     presentationOrder().m_samples.erase(presentationTime);
     decodeOrder().m_samples.erase(decodeKey);
 }

 PresentationOrderSampleMap::iterator PresentationOrderSampleMap::findSampleWithPresentationTime(const MediaTime& time)
 {
     auto range = m_samples.equal_range(time);
     if (range.first == range.second)
         return end();
     return range.first;
 }

 PresentationOrderSampleMap::iterator PresentationOrderSampleMap::findSampleContainingPresentationTime(const MediaTime& time)
 {
     // upper_bound will return the first sample whose presentation start time is greater than the search time.
     // If this is the first sample, that means no sample in the map contains the requested time.
     auto iter = m_samples.upper_bound(time);
     if (iter == begin())
         return end();

     // Look at the previous sample; does it contain the requested time?
     --iter;
     MediaSample& sample = *iter->second;
     if (sample.presentationTime() + sample.duration() > time)
         return iter;
     return end();
 }

 PresentationOrderSampleMap::iterator PresentationOrderSampleMap::findSampleContainingOrAfterPresentationTime(const MediaTime& time)
 {
     if (m_samples.empty())
         return end();

     // upper_bound will return the first sample whose presentation start time is greater than the search time.
     // If this is the first sample, that means no sample in the map contains the requested time.
     auto iter = m_samples.upper_bound(time);
     if (iter == begin())
         return iter;

     // Look at the previous sample; does it contain the requested time?
     --iter;
     MediaSample& sample = *iter->second;
     if (sample.presentationTime() + sample.duration() > time)
         return iter;
     return ++iter;
 }

 PresentationOrderSampleMap::iterator PresentationOrderSampleMap::findSampleStartingOnOrAfterPresentationTime(const MediaTime& time)
 {
     return m_samples.lower_bound(time);
 }

 PresentationOrderSampleMap::iterator PresentationOrderSampleMap::findSampleStartingAfterPresentationTime(const MediaTime& time)
 {
     return m_samples.upper_bound(time);
 }

 DecodeOrderSampleMap::iterator DecodeOrderSampleMap::findSampleWithDecodeKey(const KeyType& key)
 {
     return m_samples.find(key);
 }

 DecodeOrderSampleMap::iterator DecodeOrderSampleMap::findSampleAfterDecodeKey(const KeyType& key)
 {
     return m_samples.upper_bound(key);
 }

 PresentationOrderSampleMap::reverse_iterator PresentationOrderSampleMap::reverseFindSampleContainingPresentationTime(const MediaTime& time)
 {
     auto range = std::equal_range(rbegin(), rend(), time, SampleIsGreaterThanMediaTimeComparator<MapType>());
     if (range.first == range.second)
         return rend();
     return range.first;
 }

 PresentationOrderSampleMap::reverse_iterator PresentationOrderSampleMap::reverseFindSampleBeforePresentationTime(const MediaTime& time)
 {
     if (m_samples.empty())
         return rend();

     // upper_bound will return the first sample whose presentation start time is greater than the search time.
     auto found = m_samples.upper_bound(time);

     // If no sample was found with a time greater than the search time, return the last sample.
     if (found == end())
         return rbegin();

     // If the first sample has a time grater than the search time, no samples will have a presentation time before the search time.
     if (found == begin())
         return rend();

     // Otherwise, return the sample immediately previous to the one found.
     return --reverse_iterator(--found);
 }

 DecodeOrderSampleMap::reverse_iterator DecodeOrderSampleMap::reverseFindSampleWithDecodeKey(const KeyType& key)
 {
     DecodeOrderSampleMap::iterator found = findSampleWithDecodeKey(key);
     if (found == end())
         return rend();
     return --reverse_iterator(found);
 }

 DecodeOrderSampleMap::reverse_iterator DecodeOrderSampleMap::findSyncSamplePriorToPresentationTime(const MediaTime& time, const MediaTime& threshold)
 {
     PresentationOrderSampleMap::reverse_iterator reverseCurrentSamplePTS = m_presentationOrder.reverseFindSampleBeforePresentationTime(time);
     if (reverseCurrentSamplePTS == m_presentationOrder.rend())
         return rend();

     const RefPtr<MediaSample>& sample = reverseCurrentSamplePTS->second;
     reverse_iterator reverseCurrentSampleDTS = reverseFindSampleWithDecodeKey(KeyType(sample->decodeTime(), sample->presentationTime()));

     reverse_iterator foundSample = findSyncSamplePriorToDecodeIterator(reverseCurrentSampleDTS);
     if (foundSample == rend())
         return rend();
     if (foundSample->second->presentationTime() < time - threshold)
         return rend();
     return foundSample;
 }

 DecodeOrderSampleMap::reverse_iterator DecodeOrderSampleMap::findSyncSamplePriorToDecodeIterator(reverse_iterator iterator)
 {
     return std::find_if(iterator, rend(), SampleIsRandomAccess());
 }

 DecodeOrderSampleMap::iterator DecodeOrderSampleMap::findSyncSampleAfterPresentationTime(const MediaTime& time, const MediaTime& threshold)
 {
     PresentationOrderSampleMap::iterator currentSamplePTS = m_presentationOrder.findSampleStartingOnOrAfterPresentationTime(time);
     if (currentSamplePTS == m_presentationOrder.end())
         return end();

     const RefPtr<MediaSample>& sample = currentSamplePTS->second;
     iterator currentSampleDTS = findSampleWithDecodeKey(KeyType(sample->decodeTime(), sample->presentationTime()));

     MediaTime upperBound = time + threshold;
     iterator foundSample = std::find_if(currentSampleDTS, end(), SampleIsRandomAccess());
     if (foundSample == end())
         return end();
     if (foundSample->second->presentationTime() > upperBound)
         return end();
     return foundSample;
 }

 DecodeOrderSampleMap::iterator DecodeOrderSampleMap::findSyncSampleAfterDecodeIterator(iterator currentSampleDTS)
 {
     if (currentSampleDTS == end())
         return end();
     return std::find_if(++currentSampleDTS, end(), SampleIsRandomAccess());
 }

 PresentationOrderSampleMap::iterator_range PresentationOrderSampleMap::findSamplesBetweenPresentationTimes(const MediaTime& beginTime, const MediaTime& endTime)
 {
     // startTime is inclusive, so use lower_bound to include samples wich start exactly at startTime.
     // endTime is not inclusive, so use lower_bound to exclude samples which start exactly at endTime.
     auto lower_bound = m_samples.lower_bound(beginTime);
     auto upper_bound = m_samples.lower_bound(endTime);
     if (lower_bound == upper_bound)
         return { end(), end() };
     return { lower_bound, upper_bound };
 }

 PresentationOrderSampleMap::iterator_range PresentationOrderSampleMap::findSamplesBetweenPresentationTimesFromEnd(const MediaTime& beginTime, const MediaTime& endTime)
 {
     reverse_iterator rangeEnd = std::find_if(rbegin(), rend(), [&endTime](auto& value) {
         return value.first < endTime;
     });

     reverse_iterator rangeStart = std::find_if(rangeEnd, rend(), [&beginTime](auto& value) {
         return value.first < beginTime;
     });

     if (rangeStart == rangeEnd)
         return { end(), end() };

     // ( rangeStart, rangeEnd ] == [ rangeStart.base(), rangeEnd.base() )
     return { rangeStart.base(), rangeEnd.base() };
 }

 DecodeOrderSampleMap::reverse_iterator_range DecodeOrderSampleMap::findDependentSamples(MediaSample* sample)
 {
     ASSERT(sample);
     reverse_iterator currentDecodeIter = reverseFindSampleWithDecodeKey(KeyType(sample->decodeTime(), sample->presentationTime()));
     reverse_iterator nextSyncSample = findSyncSamplePriorToDecodeIterator(currentDecodeIter);
     return reverse_iterator_range(currentDecodeIter, nextSyncSample);
 }

 DecodeOrderSampleMap::iterator_range DecodeOrderSampleMap::findSamplesBetweenDecodeKeys(const KeyType& beginKey, const KeyType& endKey)
 {
     if (beginKey > endKey)
         return { end(), end() };

     // beginKey is inclusive, so use lower_bound to include samples wich start exactly at beginKey.
     // endKey is not inclusive, so use lower_bound to exclude samples which start exactly at endKey.
     auto lower_bound = m_samples.lower_bound(beginKey);
     auto upper_bound = m_samples.lower_bound(endKey);
     if (lower_bound == upper_bound)
         return { end(), end() };
     return { lower_bound, upper_bound };
 }

 }
	/*
	* Copyright (C) 2013 Apple Inc. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
	* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
	* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
	* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
	* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
	* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
	* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
	* THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include "config.h"
	#include "SampleMap.h"

	#include "MediaSample.h"

	namespace WebCore {

	template <typename M>
	class SampleIsLessThanMediaTimeComparator {
	public:
	typedef typename M::value_type value_type;
	bool operator()(const value_type& value, const MediaTime& time)
	{
	MediaTime presentationEndTime = value.second->presentationTime() + value.second->duration();
	return presentationEndTime <= time;
	}
	bool operator()(const MediaTime& time, const value_type& value)
	{
	MediaTime presentationStartTime = value.second->presentationTime();
	return time < presentationStartTime;
	}
	};

	template <typename M>
	class SampleIsGreaterThanMediaTimeComparator {
	public:
	typedef typename M::value_type value_type;
	bool operator()(const value_type& value, const MediaTime& time)
	{
	MediaTime presentationStartTime = value.second->presentationTime();
	return presentationStartTime > time;
	}
	bool operator()(const MediaTime& time, const value_type& value)
	{
	MediaTime presentationEndTime = value.second->presentationTime() + value.second->duration();
	return time >= presentationEndTime;
	}
	};

	class SampleIsRandomAccess {
	public:
	bool operator()(DecodeOrderSampleMap::MapType::value_type& value)
	{
	return value.second->flags() == MediaSample::IsSync;
	}
	};

	// SamplePresentationTimeIsInsideRangeComparator matches (range.first, range.second]
	struct SamplePresentationTimeIsInsideRangeComparator {
	bool operator()(std::pair<MediaTime, MediaTime> range, const std::pair<MediaTime, RefPtr<MediaSample>>& value)
	{
	return range.second < value.first;
	}
	bool operator()(const std::pair<MediaTime, RefPtr<MediaSample>>& value, std::pair<MediaTime, MediaTime> range)
	{
	return value.first <= range.first;
	}
	};

	// SamplePresentationTimeIsWithinRangeComparator matches [range.first, range.second)
	struct SamplePresentationTimeIsWithinRangeComparator {
	bool operator()(std::pair<MediaTime, MediaTime> range, const std::pair<MediaTime, RefPtr<MediaSample>>& value)
	{
	return range.second <= value.first;
	}
	bool operator()(const std::pair<MediaTime, RefPtr<MediaSample>>& value, std::pair<MediaTime, MediaTime> range)
	{
	return value.first < range.first;
	}
	};

	bool SampleMap::empty() const
	{
	return presentationOrder().m_samples.empty();
	}

	void SampleMap::clear()
	{
	presentationOrder().m_samples.clear();
	decodeOrder().m_samples.clear();
	m_totalSize = 0;
	}

	void SampleMap::addSample(MediaSample& sample)
	{
	MediaTime presentationTime = sample.presentationTime();

	presentationOrder().m_samples.insert(PresentationOrderSampleMap::MapType::value_type(presentationTime, &sample));

	auto decodeKey = DecodeOrderSampleMap::KeyType(sample.decodeTime(), presentationTime);
	decodeOrder().m_samples.insert(DecodeOrderSampleMap::MapType::value_type(decodeKey, &sample));

	m_totalSize += sample.sizeInBytes();
	}

	void SampleMap::removeSample(MediaSample* sample)
	{
	ASSERT(sample);
	MediaTime presentationTime = sample->presentationTime();

	m_totalSize -= sample->sizeInBytes();

	auto decodeKey = DecodeOrderSampleMap::KeyType(sample->decodeTime(), presentationTime);
	presentationOrder().m_samples.erase(presentationTime);
	decodeOrder().m_samples.erase(decodeKey);
	}

	PresentationOrderSampleMap::iterator PresentationOrderSampleMap::findSampleWithPresentationTime(const MediaTime& time)
	{
	auto range = m_samples.equal_range(time);
	if (range.first == range.second)
	return end();
	return range.first;
	}

	PresentationOrderSampleMap::iterator PresentationOrderSampleMap::findSampleContainingPresentationTime(const MediaTime& time)
	{
	// upper_bound will return the first sample whose presentation start time is greater than the search time.
	// If this is the first sample, that means no sample in the map contains the requested time.
	auto iter = m_samples.upper_bound(time);
	if (iter == begin())
	return end();

	// Look at the previous sample; does it contain the requested time?
	--iter;
	MediaSample& sample = *iter->second;
	if (sample.presentationTime() + sample.duration() > time)
	return iter;
	return end();
	}

	PresentationOrderSampleMap::iterator PresentationOrderSampleMap::findSampleContainingOrAfterPresentationTime(const MediaTime& time)
	{
	if (m_samples.empty())
	return end();

	// upper_bound will return the first sample whose presentation start time is greater than the search time.
	// If this is the first sample, that means no sample in the map contains the requested time.
	auto iter = m_samples.upper_bound(time);
	if (iter == begin())
	return iter;

	// Look at the previous sample; does it contain the requested time?
	--iter;
	MediaSample& sample = *iter->second;
	if (sample.presentationTime() + sample.duration() > time)
	return iter;
	return ++iter;
	}

	PresentationOrderSampleMap::iterator PresentationOrderSampleMap::findSampleStartingOnOrAfterPresentationTime(const MediaTime& time)
	{
	return m_samples.lower_bound(time);
	}

	PresentationOrderSampleMap::iterator PresentationOrderSampleMap::findSampleStartingAfterPresentationTime(const MediaTime& time)
	{
	return m_samples.upper_bound(time);
	}

	DecodeOrderSampleMap::iterator DecodeOrderSampleMap::findSampleWithDecodeKey(const KeyType& key)
	{
	return m_samples.find(key);
	}

	DecodeOrderSampleMap::iterator DecodeOrderSampleMap::findSampleAfterDecodeKey(const KeyType& key)
	{
	return m_samples.upper_bound(key);
	}

	PresentationOrderSampleMap::reverse_iterator PresentationOrderSampleMap::reverseFindSampleContainingPresentationTime(const MediaTime& time)
	{
	auto range = std::equal_range(rbegin(), rend(), time, SampleIsGreaterThanMediaTimeComparator<MapType>());
	if (range.first == range.second)
	return rend();
	return range.first;
	}

	PresentationOrderSampleMap::reverse_iterator PresentationOrderSampleMap::reverseFindSampleBeforePresentationTime(const MediaTime& time)
	{
	if (m_samples.empty())
	return rend();

	// upper_bound will return the first sample whose presentation start time is greater than the search time.
	auto found = m_samples.upper_bound(time);

	// If no sample was found with a time greater than the search time, return the last sample.
	if (found == end())
	return rbegin();

	// If the first sample has a time grater than the search time, no samples will have a presentation time before the search time.
	if (found == begin())
	return rend();

	// Otherwise, return the sample immediately previous to the one found.
	return --reverse_iterator(--found);
	}

	DecodeOrderSampleMap::reverse_iterator DecodeOrderSampleMap::reverseFindSampleWithDecodeKey(const KeyType& key)
	{
	DecodeOrderSampleMap::iterator found = findSampleWithDecodeKey(key);
	if (found == end())
	return rend();
	return --reverse_iterator(found);
	}

	DecodeOrderSampleMap::reverse_iterator DecodeOrderSampleMap::findSyncSamplePriorToPresentationTime(const MediaTime& time, const MediaTime& threshold)
	{
	PresentationOrderSampleMap::reverse_iterator reverseCurrentSamplePTS = m_presentationOrder.reverseFindSampleBeforePresentationTime(time);
	if (reverseCurrentSamplePTS == m_presentationOrder.rend())
	return rend();

	const RefPtr<MediaSample>& sample = reverseCurrentSamplePTS->second;
	reverse_iterator reverseCurrentSampleDTS = reverseFindSampleWithDecodeKey(KeyType(sample->decodeTime(), sample->presentationTime()));

	reverse_iterator foundSample = findSyncSamplePriorToDecodeIterator(reverseCurrentSampleDTS);
	if (foundSample == rend())
	return rend();
	if (foundSample->second->presentationTime() < time - threshold)
	return rend();
	return foundSample;
	}

	DecodeOrderSampleMap::reverse_iterator DecodeOrderSampleMap::findSyncSamplePriorToDecodeIterator(reverse_iterator iterator)
	{
	return std::find_if(iterator, rend(), SampleIsRandomAccess());
	}

	DecodeOrderSampleMap::iterator DecodeOrderSampleMap::findSyncSampleAfterPresentationTime(const MediaTime& time, const MediaTime& threshold)
	{
	PresentationOrderSampleMap::iterator currentSamplePTS = m_presentationOrder.findSampleStartingOnOrAfterPresentationTime(time);
	if (currentSamplePTS == m_presentationOrder.end())
	return end();

	const RefPtr<MediaSample>& sample = currentSamplePTS->second;
	iterator currentSampleDTS = findSampleWithDecodeKey(KeyType(sample->decodeTime(), sample->presentationTime()));

	MediaTime upperBound = time + threshold;
	iterator foundSample = std::find_if(currentSampleDTS, end(), SampleIsRandomAccess());
	if (foundSample == end())
	return end();
	if (foundSample->second->presentationTime() > upperBound)
	return end();
	return foundSample;
	}

	DecodeOrderSampleMap::iterator DecodeOrderSampleMap::findSyncSampleAfterDecodeIterator(iterator currentSampleDTS)
	{
	if (currentSampleDTS == end())
	return end();
	return std::find_if(++currentSampleDTS, end(), SampleIsRandomAccess());
	}

	PresentationOrderSampleMap::iterator_range PresentationOrderSampleMap::findSamplesBetweenPresentationTimes(const MediaTime& beginTime, const MediaTime& endTime)
	{
	// startTime is inclusive, so use lower_bound to include samples wich start exactly at startTime.
	// endTime is not inclusive, so use lower_bound to exclude samples which start exactly at endTime.
	auto lower_bound = m_samples.lower_bound(beginTime);
	auto upper_bound = m_samples.lower_bound(endTime);
	if (lower_bound == upper_bound)
	return { end(), end() };
	return { lower_bound, upper_bound };
	}

	PresentationOrderSampleMap::iterator_range PresentationOrderSampleMap::findSamplesBetweenPresentationTimesFromEnd(const MediaTime& beginTime, const MediaTime& endTime)
	{
	reverse_iterator rangeEnd = std::find_if(rbegin(), rend(), [&endTime](auto& value) {
	return value.first < endTime;
	});

	reverse_iterator rangeStart = std::find_if(rangeEnd, rend(), [&beginTime](auto& value) {
	return value.first < beginTime;
	});

	if (rangeStart == rangeEnd)
	return { end(), end() };

	// ( rangeStart, rangeEnd ] == [ rangeStart.base(), rangeEnd.base() )
	return { rangeStart.base(), rangeEnd.base() };
	}

	DecodeOrderSampleMap::reverse_iterator_range DecodeOrderSampleMap::findDependentSamples(MediaSample* sample)
	{
	ASSERT(sample);
	reverse_iterator currentDecodeIter = reverseFindSampleWithDecodeKey(KeyType(sample->decodeTime(), sample->presentationTime()));
	reverse_iterator nextSyncSample = findSyncSamplePriorToDecodeIterator(currentDecodeIter);
	return reverse_iterator_range(currentDecodeIter, nextSyncSample);
	}

	DecodeOrderSampleMap::iterator_range DecodeOrderSampleMap::findSamplesBetweenDecodeKeys(const KeyType& beginKey, const KeyType& endKey)
	{
	if (beginKey > endKey)
	return { end(), end() };

	// beginKey is inclusive, so use lower_bound to include samples wich start exactly at beginKey.
	// endKey is not inclusive, so use lower_bound to exclude samples which start exactly at endKey.
	auto lower_bound = m_samples.lower_bound(beginKey);
	auto upper_bound = m_samples.lower_bound(endKey);
	if (lower_bound == upper_bound)
	return { end(), end() };
	return { lower_bound, upper_bound };
	}

	}