PhantomAudioClip.cpp   [plain text]

/*
  File:PhantomAudioClip.cpp

  Contains:

  Version:1.0.0

  Copyright:Copyright ) 1997-2000 by Apple Computer, Inc., All Rights Reserved.

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*/

#include "PhantomAudioEngine.h"
#include <IOKit/IOLib.h>

#define	Use_Optimized	1

#if	Use_Optimized
	#include "PCMBlitterLibPPC.h"
#endif

// The function clipOutputSamples() is called to clip and convert samples from the float mix buffer into the actual
// hardware sample buffer.  The samples to be clipped, are guaranteed not to wrap from the end of the buffer to the
// beginning.
// This implementation is very inefficient, but illustrates the clip and conversion process that must take place.
// Each floating-point sample must be clipped to a range of -1.0 to 1.0 and then converted to the hardware buffer
// format

// The parameters are as follows:
//		mixBuf - a pointer to the beginning of the float mix buffer - its size is based on the number of sample frames
// 					times the number of channels for the stream
//		sampleBuf - a pointer to the beginning of the hardware formatted sample buffer - this is the same buffer passed
//					to the IOAudioStream using setSampleBuffer()
//		firstSampleFrame - this is the index of the first sample frame to perform the clipping and conversion on
//		numSampleFrames - the total number of sample frames to clip and convert
//		streamFormat - the current format of the IOAudioStream this function is operating on
//		audioStream - the audio stream this function is operating on
IOReturn PhantomAudioEngine::clipOutputSamples(const void *mixBuf, void *sampleBuf, UInt32 firstSampleFrame, UInt32 numSampleFrames, const IOAudioStreamFormat *streamFormat, IOAudioStream *audioStream)
{
    return kIOReturnSuccess;
}

extern "C" {

IOReturn clip24BitSamples(const void *mixBuf, void *sampleBuf, UInt32 firstSampleFrame, UInt32 numSampleFrames, const IOAudioStreamFormat *streamFormat, IOAudioStream *audioStream)
{
	if (streamFormat->fIsMixable) {
	#if	Use_Optimized
		Float32ToNativeInt32(&(((float *)mixBuf)[firstSampleFrame]), &(((long *)sampleBuf)[firstSampleFrame]), numSampleFrames * streamFormat->fNumChannels);
	#else
		float *floatMixBuf;
		SInt32 *outputBuf;    
		UInt32 sampleIndex;
		UInt32 maxSampleIndex;
		float mixSample;
		
		IOLog( "clip24(%x,%x)\n", firstSampleFrame, numSampleFrames );
		
		floatMixBuf = &(((float *)mixBuf)[firstSampleFrame]);
		outputBuf = (SInt32 *)sampleBuf;
		
		maxSampleIndex = firstSampleFrame + numSampleFrames;
		
		for ( sampleIndex = firstSampleFrame; sampleIndex < maxSampleIndex; sampleIndex++ ) {
			mixSample = *floatMixBuf++;
			mixSample *= 2147483648.0;
			if (mixSample > 2147483392.0) {
				mixSample = 2147483392.0;
			} else if (mixSample < -2147483648.0) {
				mixSample = -2147483648.0;
			}
		
			outputBuf[sampleIndex] = (SInt32)(mixSample);
		}
	#endif
	} else {
		UInt32			offset;

		offset = firstSampleFrame * streamFormat->fNumChannels * (streamFormat->fBitWidth / 8);

		memcpy ((UInt8 *)sampleBuf + offset, (UInt8 *)mixBuf, numSampleFrames * streamFormat->fNumChannels * (streamFormat->fBitWidth / 8));
	}

    return kIOReturnSuccess;
}

IOReturn clip16BitSamples(const void *mixBuf, void *sampleBuf, UInt32 firstSampleFrame, UInt32 numSampleFrames, const IOAudioStreamFormat *streamFormat, IOAudioStream *audioStream)
{
	if (streamFormat->fIsMixable) {
	#if	Use_Optimized
		Float32ToNativeInt16(&(((float *)mixBuf)[firstSampleFrame]), &(((int16_t *)sampleBuf)[firstSampleFrame]), numSampleFrames * streamFormat->fNumChannels);
	#else
		float *floatMixBuf;
		SInt32 *outputBuf;    
		UInt32 sampleIndex;
		UInt32 maxSampleIndex;
		float mixSample;
		
		floatMixBuf = &(((float *)mixBuf)[firstSampleFrame]);
		outputBuf = &(((SInt32 *)sampleBuf)[firstSampleFrame]);
		
		maxSampleIndex = firstSampleFrame + numSampleFrames;
		
		for ( sampleIndex = firstSampleFrame; sampleIndex < maxSampleIndex; sampleIndex++ ) {
			mixSample = *floatMixBuf++;
			mixSample *= 2147483648.0;
			if (mixSample > 2147483392.0) {
				mixSample = 2147483392.0;
			} else if (mixSample < -2147483648.0) {
				mixSample = -2147483648.0;
			}
	
		outputBuf[sampleIndex] = (SInt32)(mixSample);
	
			++outputBuf;
		}
	#endif
	} else {
		UInt32			offset;

		offset = firstSampleFrame * streamFormat->fNumChannels * (streamFormat->fBitWidth / 8);

		memcpy ((UInt8 *)sampleBuf + offset, (UInt8 *)mixBuf, numSampleFrames * streamFormat->fNumChannels * (streamFormat->fBitWidth / 8));
	}

    return kIOReturnSuccess;
}

IOReturn process24BitSamples(const void *mixBuf, void *sampleBuf, UInt32 firstSampleFrame, UInt32 numSampleFrames, const IOAudioStreamFormat *streamFormat, IOAudioStream *audioStream)
{
    //IOLog("process24BitSamples(%lx,%lx)\n", firstSampleFrame, numSampleFrames);
    return kIOReturnSuccess;
}

IOReturn process16BitSamples(const void *mixBuf, void *sampleBuf, UInt32 firstSampleFrame, UInt32 numSampleFrames, const IOAudioStreamFormat *streamFormat, IOAudioStream *audioStream)
{
    //IOLog("process16BitSamples(%lx,%lx)\n", firstSampleFrame, numSampleFrames);
    return kIOReturnSuccess;
}

}


// The function convertInputSamples() is responsible for converting from the hardware format 
// in the input sample buffer to float samples in the destination buffer and scale the samples 
// to a range of -1.0 to 1.0.  This function is guaranteed not to have the samples wrapped
// from the end of the buffer to the beginning.
// This function only needs to be implemented if the device has any input IOAudioStreams

// The parameters are as follows:
//		sampleBuf - a pointer to the beginning of the hardware formatted sample buffer - this is the same buffer passed
//					to the IOAudioStream using setSampleBuffer()
//		destBuf - a pointer to the float destination buffer - this is the buffer that the CoreAudio.framework uses
//					its size is numSampleFrames * numChannels * sizeof(float)
//		firstSampleFrame - this is the index of the first sample frame to the input conversion on
//		numSampleFrames - the total number of sample frames to convert and scale
//		streamFormat - the current format of the IOAudioStream this function is operating on
//		audioStream - the audio stream this function is operating on
IOReturn PhantomAudioEngine::convertInputSamples(const void *sampleBuf, void *destBuf, UInt32 firstSampleFrame, UInt32 numSampleFrames, const IOAudioStreamFormat *streamFormat, IOAudioStream *audioStream)
{
#if	Use_Optimized
	NativeInt32ToFloat32(&(((long *)sampleBuf)[firstSampleFrame]), &(((float *)sampleBuf)[firstSampleFrame]), numSampleFrames * streamFormat->fNumChannels, 32);
#else
    SInt32	*inputBuf;
    float	*floatDestBuf;
    SInt32 inputSample;
    
    IOLog( "conv24(%x,%x)\n", firstSampleFrame, numSampleFrames );
    
    floatDestBuf = (float *)destBuf;
    inputBuf = &(((SInt32 *)sampleBuf)[firstSampleFrame]);
    
    while ( numSampleFrames > 0 )
    {
        inputSample = *inputBuf;
        *floatDestBuf++ = (float)(inputSample) * 4.656612873077392578125e-10;
        inputBuf++;
        --numSampleFrames;
    }
#endif
    return kIOReturnSuccess;
}