ITABiquad.cpp

#include <ITABiquad.h>
#include <ITAException.h>
#include <ITABaseDefinitions.h>

CITABiquad::CITABiquad()
{
	ClearAccumulators();
}

void CITABiquad::ClearAccumulators()
{
	m_vfAccumulators.push_back( 0.0f );
	m_vfAccumulators.push_back( 0.0f );
}

void CITABiquad::Process( const float* pfInputData, float* pfOutputData, const int iNumSamples )
{
	// Local accumulators
	float z0, z1, z2;

	// Restore accumulators from last process call
	z1 = m_vfAccumulators[ 0 ];
	z2 = m_vfAccumulators[ 1 ];

	for( int i = 0; i < iNumSamples; i++ )
	{
		// w[n] = x[n] - a_1*w[n-1] - a_2*w[n-2]
		z0 = oParams.g * pfInputData[ i ] - oParams.a1 * z1 - oParams.a2 * z2;

		// y[n] = b_0*w[n] + b_1*w[n-1] + b_2*w[n-2]
		pfOutputData[ i ] = oParams.b0 * z0 + oParams.b1 * z1 + oParams.b2 * z2;

		// Shift accumulators
		z2 = z1;
		z1 = z0;
	}

	// Store accumulators for next process call
	m_vfAccumulators[ 0 ] = z1;
	m_vfAccumulators[ 1 ] = z2;

	return;
}

void CITABiquad::Process( const float* pfInputData, float* pfOutputData, const int iNumSamples, const float fOutputGain, const int iOutputMode )
{
	// Local accumulators
	float z0, z1, z2;

	z1 = m_vfAccumulators[ 0 ];
	z2 = m_vfAccumulators[ 1 ];

	if( iOutputMode == ITABase::MixingMethod::ADD )
	{
		for( int i = 0; i < iNumSamples; i++ )
		{
			z0 = oParams.g * pfInputData[ i ] - oParams.a1*z1 - oParams.a2*z2;
			pfOutputData[ i ] += ( oParams.b0*z0 + oParams.b1*z1 + oParams.b2*z2 ) * fOutputGain;

			// Shift accumulators
			z2 = z1;
			z1 = z0;
		}
	}
	else if( iOutputMode == ITABase::MixingMethod::OVERWRITE )
	{
		for( int i = 0; i < iNumSamples; i++ )
		{
			z0 = oParams.g*pfInputData[ i ] - oParams.a1*z1 - oParams.a2*z2;
			pfOutputData[ i ] = ( oParams.b0 * z0 + oParams.b1 * z1 + oParams.b2*z2 ) * fOutputGain;

			// Shift accumulators
			z2 = z1;
			z1 = z0;
		}
	}
	else
	{
		ITA_EXCEPT1( INVALID_PARAMETER, "Unrecognized output write mode in CITABiquad" );
	}

	// Store accumulators
	m_vfAccumulators[ 0 ] = z1;
	m_vfAccumulators[ 1 ] = z2;

	return;
}

void CITABiquad::Process( const float* pfInputData, float* out, const int iNumSamples, const float fOutputGain1, const float fOutputGain2, const int iOutputWriteMode )
{
	if( iNumSamples == 0 )
		return;

	// Local accumulators
	float z0, z1, z2;
	z1 = m_vfAccumulators[ 0 ];
	z2 = m_vfAccumulators[ 1 ];

	// Factor for linear gain
	const float fLinearGainFactor = ( fOutputGain2 - fOutputGain1 ) / float( iNumSamples );

	if( iOutputWriteMode == ITABase::MixingMethod::ADD )
	{
		for( int i = 0; i < iNumSamples; i++ )
		{
			const float fSampleGain = fOutputGain1 + i * fLinearGainFactor;

			z0 = oParams.g*pfInputData[ i ] - oParams.a1*z1 - oParams.a2*z2;
			out[ i ] += ( oParams.b0*z0 + oParams.b1*z1 + oParams.b2*z2 ) * fSampleGain;

			// Shift accumulators
			z2 = z1;
			z1 = z0;
		}

	}
	else if( iOutputWriteMode == ITABase::MixingMethod::OVERWRITE )
	{
		for( int i = 0; i < iNumSamples; i++ )
		{
			const float fSampleGain = fOutputGain1 + i * fLinearGainFactor;

			z0 = oParams.g*pfInputData[ i ] - oParams.a1*z1 - oParams.a2*z2;
			out[ i ] = ( oParams.b0*z0 + oParams.b1*z1 + oParams.b2*z2 ) * fSampleGain;

			// Shift accumulators
			z2 = z1;
			z1 = z0;
		}
	}
	else
	{
		ITA_EXCEPT1( INVALID_PARAMETER, "Unrecognized output write mode in CITABiquad" );
	}

	// Store accumulators
	m_vfAccumulators[ 0 ] = z1;
	m_vfAccumulators[ 1 ] = z2;
}

CITABiquad::CParams::CParams()
	: g( 1 )
	, a1( 0 )
	, a2( 0 )
	, b0( 1 )
	, b1( 0 )
	, b2( 0 )
{
}