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/*=============================================================================
	ACSimpleCodec.cpp

=============================================================================*/

//=============================================================================
//	Includes
//=============================================================================

#include "ACSimpleCodec.h"
#include <string.h>

//=============================================================================
//	ACSimpleCodec
//=============================================================================

static const UInt32 kBufferPad = 64; // this is used to prevent end from passing start.

ACSimpleCodec::ACSimpleCodec(UInt32 inInputBufferByteSize)
:
	ACBaseCodec(),
	mInputBuffer(NULL),
	mInputBufferByteSize(inInputBufferByteSize+kBufferPad),
	mInputBufferStart(0),
	mInputBufferEnd(0)
{
}

ACSimpleCodec::~ACSimpleCodec()
{
	delete[] mInputBuffer;
}

void	ACSimpleCodec::Initialize(const AudioStreamBasicDescription* inInputFormat, const AudioStreamBasicDescription* inOutputFormat, const void* inMagicCookie, UInt32 inMagicCookieByteSize)
{
	ReallocateInputBuffer(mInputBufferByteSize - kBufferPad);
	
	ACBaseCodec::Initialize(inInputFormat, inOutputFormat, inMagicCookie, inMagicCookieByteSize);
}

void	ACSimpleCodec::Uninitialize()
{
	//	get rid of the buffer
	delete[] mInputBuffer;
	mInputBuffer = NULL;
	
	//	reset the ring buffer state
	mInputBufferStart = 0;
	mInputBufferEnd = 0;
	
	ACBaseCodec::Uninitialize();
}

void	ACSimpleCodec::Reset()
{
	//	clear the entire input buffer
	if (mInputBuffer) { // could be called before allocated.
		memset(mInputBuffer, 0, mInputBufferByteSize);
	}
	
	//	reset the ring buffer state
	mInputBufferStart = 0;
	mInputBufferEnd = 0;
	
	ACBaseCodec::Reset();
}

UInt32	ACSimpleCodec::GetInputBufferByteSize() const
{
	return mInputBufferByteSize - kBufferPad; // minus kBufferPad to prevent end moving past start
}

UInt32	ACSimpleCodec::GetUsedInputBufferByteSize() const
{
	UInt32 theAnswer = 0;
	
	//	this object uses a ring buffer
	if(mInputBufferStart <= mInputBufferEnd)
	{
		//	the active region is contiguous
		theAnswer = mInputBufferEnd - mInputBufferStart;
	}
	else
	{
		//	the active region wraps around 
		theAnswer = (mInputBufferByteSize - mInputBufferStart) + mInputBufferEnd;
	}
	
	return theAnswer;
}


void	ACSimpleCodec::AppendInputData(const void* inInputData, UInt32& ioInputDataByteSize, UInt32& ioNumberPackets, const AudioStreamPacketDescription* inPacketDescription)
{
	//	this buffer handling code doesn't care about such things as the packet descriptions
	if(!mIsInitialized) CODEC_THROW(kAudioCodecStateError);
	
	//	this is a ring buffer we're dealing with, so we need to set up a few things
	UInt32 theUsedByteSize = GetUsedInputBufferByteSize();
	UInt32 theAvailableByteSize = GetInputBufferByteSize() - theUsedByteSize;

	UInt32 theMaxAvailableInputBytes = ioInputDataByteSize; // we can't consume more than we get

	const Byte* theInputData = static_cast<const Byte*>(inInputData);
	
	// >>jamesmcc: added this because ioNumberPackets was not being updated if less was taken than given.
	// THIS ASSUMES CBR!
	UInt32 bytesPerPacketOfInput = mInputFormat.mBytesPerPacket;
	UInt32 theAvailablePacketSize = theAvailableByteSize / bytesPerPacketOfInput;
	
	UInt32 minPacketSize = ioNumberPackets < theAvailablePacketSize ? ioNumberPackets : theAvailablePacketSize;
	UInt32 minByteSize = minPacketSize * bytesPerPacketOfInput;
	
	//	we can copy only as much data as there is or up to how much space is availiable
	ioNumberPackets = minPacketSize;
	ioInputDataByteSize = minByteSize;
	
	// ioInputDataByteSize had better be <= to theMaxAvailableInputBytes or we're screwed
	if (ioInputDataByteSize > theMaxAvailableInputBytes)
	{
		CODEC_THROW(kAudioCodecStateError);
	}
	// <<jamesmcc 
	
	//	now we have to copy the data taking into account the wrap around and where the start is
	if(mInputBufferEnd + ioInputDataByteSize < mInputBufferByteSize)
	{
		//	no wrap around here
		memcpy(mInputBuffer + mInputBufferEnd, theInputData, ioInputDataByteSize);
		
		//	adjust the end point
		mInputBufferEnd += ioInputDataByteSize;
	}
	else
	{
		//	the copy will wrap
		
		//	copy the first part
		UInt32 theBeforeWrapByteSize = mInputBufferByteSize - mInputBufferEnd;
		memcpy(mInputBuffer + mInputBufferEnd, theInputData, theBeforeWrapByteSize);
		
		//	and the rest
		UInt32 theAfterWrapByteSize = ioInputDataByteSize - theBeforeWrapByteSize;
		memcpy(mInputBuffer, theInputData + theBeforeWrapByteSize, theAfterWrapByteSize);
		
		//	adjust the end point
		mInputBufferEnd = theAfterWrapByteSize;
	}
	
}


void	ACSimpleCodec::ZeroPadInputData(UInt32& ioNumberPackets, const AudioStreamPacketDescription* inPacketDescription)
{
	//	this buffer handling code doesn't care about such things as the packet descriptions
	if(!mIsInitialized) CODEC_THROW(kAudioCodecStateError);
	
	
	//	this is a ring buffer we're dealing with, so we need to set up a few things
	UInt32 theUsedByteSize = GetUsedInputBufferByteSize();
	UInt32 theAvailableByteSize = GetInputBufferByteSize() - theUsedByteSize;
	
	// >>jamesmcc: added this because ioNumberPackets was not being updated if less was taken than given.
	// THIS ASSUMES CBR!
	UInt32 bytesPerPacketOfInput = mInputFormat.mBytesPerPacket;
	UInt32 theAvailablePacketSize = theAvailableByteSize / bytesPerPacketOfInput;
	
	UInt32 minPacketSize = ioNumberPackets < theAvailablePacketSize ? ioNumberPackets : theAvailablePacketSize;
	UInt32 minByteSize = minPacketSize * bytesPerPacketOfInput;
	
	//	we can copy only as much data as there is or up to how much space is availiable
	ioNumberPackets = minPacketSize;
	
	// <<jamesmcc 
	
	//	now we have to copy the data taking into account the wrap around and where the start is
	if(mInputBufferEnd + minByteSize < mInputBufferByteSize)
	{
		//	no wrap around here
		memset(mInputBuffer + mInputBufferEnd, 0, minByteSize);
		
		//	adjust the end point
		mInputBufferEnd += minByteSize;
	}
	else
	{
		//	the copy will wrap
		
		//	copy the first part
		UInt32 theBeforeWrapByteSize = mInputBufferByteSize - mInputBufferEnd;
		memset(mInputBuffer + mInputBufferEnd, 0, theBeforeWrapByteSize);
		
		//	and the rest
		UInt32 theAfterWrapByteSize = minByteSize - theBeforeWrapByteSize;
		memset(mInputBuffer, 0, theAfterWrapByteSize);
		
		//	adjust the end point
		mInputBufferEnd = theAfterWrapByteSize;
	}
}


void	ACSimpleCodec::ConsumeInputData(UInt32 inConsumedByteSize)
{
	//	this is a convenience routine to make maintaining the ring buffer state easy
	UInt32 theContiguousRange = GetInputBufferContiguousByteSize();
	
	if(inConsumedByteSize > GetUsedInputBufferByteSize()) CODEC_THROW(kAudioCodecUnspecifiedError);
	
	if(inConsumedByteSize <= theContiguousRange)
	{
		//	the region to consume doesn't wrap
		
		//	figure out how much to consume
		inConsumedByteSize = (theContiguousRange < inConsumedByteSize) ? theContiguousRange : inConsumedByteSize;
		
		//	clear the consumed bits
		memset(mInputBuffer + mInputBufferStart, 0, inConsumedByteSize);
		
		//	adjust the start
		mInputBufferStart += inConsumedByteSize;
	}
	else
	{
		//	the region to consume will wrap
		
		//	clear the bits to the end of the buffer
		memset(mInputBuffer + mInputBufferStart, 0, theContiguousRange);
		
		//	now clear the bits left from the start
		memset(mInputBuffer, 0, inConsumedByteSize - theContiguousRange);
		
		//	adjust the start
		mInputBufferStart = inConsumedByteSize - theContiguousRange;
	}
}


Byte* ACSimpleCodec::GetBytes(UInt32& ioNumberBytes) const
{
	// if a client's algorithm has to have contiguous data and mInputBuffer wraps, then someone has to make a copy.
	// I can do it more efficiently than the client. 
	
	if(!mIsInitialized) CODEC_THROW(kAudioCodecStateError);

	UInt32 theUsedByteSize = GetUsedInputBufferByteSize();
	//UInt32 theAvailableByteSize = GetInputBufferByteSize() - theUsedByteSize;
	
	if (ioNumberBytes > theUsedByteSize) ioNumberBytes = theUsedByteSize;
		
	SInt32 leftOver = mInputBufferStart + ioNumberBytes - mInputBufferByteSize;
	
	if(leftOver > 0)
	{
		// need to copy beginning of buffer to the end. 
		// We cleverly over allocated our buffer space to make this possible.
		memcpy(mInputBuffer + mInputBufferByteSize, mInputBuffer, leftOver);
	}
	
	return GetInputBufferStart();
}


void	ACSimpleCodec::ReallocateInputBuffer(UInt32 inInputBufferByteSize)
{
	mInputBufferByteSize = inInputBufferByteSize + kBufferPad;
	
	//	toss the old buffer
	delete[] mInputBuffer;
	mInputBuffer = NULL;
	
	//	allocate the new one
	// allocate extra in order to allow making contiguous data.
	UInt32 allocSize = 2*inInputBufferByteSize + kBufferPad;
	mInputBuffer = new Byte[allocSize];
	memset(mInputBuffer, 0, allocSize);
	
	//	reset the ring buffer state
	mInputBufferStart = 0;
	mInputBufferEnd = 0;
}

void	ACSimpleCodec::GetPropertyInfo(AudioCodecPropertyID inPropertyID, UInt32& outPropertyDataSize, bool& outWritable)
{
	switch(inPropertyID)
	{
		case kAudioCodecPropertyInputBufferSize:
			outPropertyDataSize = sizeof(UInt32);
			outWritable = true;
			break;
		default:
			ACBaseCodec::GetPropertyInfo(inPropertyID, outPropertyDataSize, outWritable);
			break;
	}

}

void	ACSimpleCodec::SetProperty(AudioCodecPropertyID inPropertyID, UInt32 inPropertyDataSize, const void* inPropertyData)
{
	switch(inPropertyID)
	{
		case kAudioCodecPropertyInputBufferSize:
			if(inPropertyDataSize == sizeof(UInt32))
			{
				ReallocateInputBuffer(*reinterpret_cast<const UInt32*>(inPropertyData));
			}
			else
			{
				CODEC_THROW(kAudioCodecBadPropertySizeError);
			}
			break;
		default:
            ACBaseCodec::SetProperty(inPropertyID, inPropertyDataSize, inPropertyData);
            break;            
    }
}
