RIFFReader.cpp
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	#include <echo/Resource/RIFFReader.h>

	namespace Echo
	{
	RIFFReader::RIFFReader()
	{
	AddChunkTypeProcessor(0x46464952,this,&RIFFReader::RIFFCheck); //RIFF type
	mCurrentChunkSize=0;
	mCurrentChunkAbsoluteOffset=0;
	mCurrentChunkID=0;
	mFormat=0;
	mRIFFOk=false;
	}

	RIFFReader::~RIFFReader()
	{
	Close();
	std::map< u32, RIFFChunkProcessorFunctor* >::iterator it=mChunkProcessors.begin();
	std::map< u32, RIFFChunkProcessorFunctor* >::iterator itEnd=mChunkProcessors.end();
	while(it!=itEnd)
	{
	delete it->second;
	++it;
	}
	}

	//This needs to be called first
	bool RIFFReader::RIFFCheck(RIFFReader* reader)
	{
	mRIFFOk=true;
	mFileSize=mCurrentChunkSize;
	//PIFF chunk is
	//4 bytes for format followed by sub chunk
	mFile.Read(&mFormat,1,4); //Get the format
	//Forces sub chunk read
	//Move the cursor 4 bytes forward and set the chunk size to 0
	//that is effectively an advanced cursor move.
	mCurrentChunkSize=0;
	mCurrentChunkAbsoluteOffset=4;
	return true;
	}

	//Chunk only chunks are chunks that contain chunks. These chunks' sub chunks are
	//automatically traversed. Which means that if one of these chunk ids is found
	//on a call to ProcessNext the sub chunk will automatically be processed.
	//Returns true on success. false indicates a processor has been defined for chunk
	bool RIFFReader::AddChunkType(u32 chunkID)
	{
	std::map< u32, RIFFChunkProcessorFunctor* >::iterator it=mChunkProcessors.find(chunkID);
	if(it!=mChunkProcessors.end())
	return false;
	mChunkProcessors[chunkID]=0;
	return true;
	}

	bool RIFFReader::SetFile(File file)
	{
	mFile = file;
	if(!mFile.IsOpen())
	{
	return false;
	}
	mFile.Seek(0);
	return ProcessNext(); //First process should be RIFF header
	}

	bool RIFFReader::ProcessAll()
	{
	if(!mFile.IsOpen())
	{
	return false;
	}

	mCurrentChunkID=0;
	//Start at beginning
	mCurrentChunkAbsoluteOffset=0;
	mCurrentChunkSize=0;
	while(!mFile.EndOfFile())
	{
	if(!ProcessNext())
	return false;
	}
	return true;
	}

	bool RIFFReader::ProcessNext()
	{
	if(mCurrentChunkSize&1) //Chunks should be even in size
	++mCurrentChunkSize;
	if(mCurrentChunkAbsoluteOffset>0) //If its not the start of the file we'll move the cursor
	mCurrentChunkAbsoluteOffset+=mCurrentChunkSize+8;//8 is the size of the chunk header

	mFile.Seek(mCurrentChunkAbsoluteOffset); //The state of the file cursor is
	//unknown after processing so ensure
	//the next chunk start
	if(mFile.Read(&mCurrentChunkID,1,4)!=4) //Get chunk id
	return false;
	if(mFile.Read(&mCurrentChunkSize,1,4)!=4) //Get chunk size
	return false;

	std::map< u32, RIFFChunkProcessorFunctor* >::iterator it=mChunkProcessors.find(mCurrentChunkID);
	if(it!=mChunkProcessors.end())
	{
	if(!(it->second)) //This chunk contains sub chunks
	{
	//Change the chunk size to reflect skip to sub chunk
	mCurrentChunkSize=0; //Two u32's
	return ProcessNext();
	}else
	{
	//Call the processor
	if(!((*it->second)(this)))
	{
	//If the processor returned false we end processing
	Close();
	return false;
	}
	if(!mRIFFOk)
	return false;
	}
	}
	return true;
	}

	u32 RIFFReader::GetCurrentChunkSize()
	{
	return mCurrentChunkSize;
	}

	u32 RIFFReader::GetSaidFileSize()
	{
	return mFileSize;
	}

	u32 RIFFReader::GetActualFileSize()
	{
	return mFile.GetSize();
	}

	void RIFFReader::ReturnToChunkStart()
	{
	mFile.Seek(mCurrentChunkAbsoluteOffset+8); //The state of the file cursor is
	}

	u32 RIFFReader::BookmarkCurrentChunk(u32 bookMarkID)
	{
	if(bookMarkID==0)
	bookMarkID=mCurrentChunkID;
	mSavedChunkLocations[bookMarkID]=mCurrentChunkAbsoluteOffset;
	return bookMarkID;
	}

	bool RIFFReader::ReturnToBookmarkedChunk(u32 bookMarkID)
	{
	std::map< u32, u32 >::iterator it=mSavedChunkLocations.find(bookMarkID);
	if(it!=mSavedChunkLocations.end())
	{
	mFile.Seek(it->second);
	mCurrentChunkAbsoluteOffset=it->second;
	if(mFile.Read(&mCurrentChunkID,1,4)!=4) //Get chunk id
	return false;
	if(mFile.Read(&mCurrentChunkSize,1,4)!=4) //Get chunk size
	return false;
	return true;
	}
	return false;
	}


	u32 RIFFReader::Read(void* buffer, u32 typeSize, u32 numToGet)
	{
	u32 bytesRemaining=mFile.GetPosition()-(mCurrentChunkAbsoluteOffset+8);
	bytesRemaining=mCurrentChunkSize-bytesRemaining;
	u32 bytesTotal=typeSize*numToGet;
	if(bytesTotal>bytesRemaining)
	{
	if(typeSize==1)
	numToGet=bytesRemaining;
	else
	{
	u32 numLess=bytesRemaining/typeSize;
	numToGet-=numLess;
	}
	}
	return mFile.Read(buffer,typeSize,numToGet);
	}

	bool RIFFReader::IsReadAtEndOfChunk()
	{
	return (mFile.GetPosition()>=(mCurrentChunkAbsoluteOffset+8+mCurrentChunkSize));
	}

	void RIFFReader::Close()
	{
	mFile.Close();
	}
	}

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