Fir.h

#ifndef STK_FIR_H
#define STK_FIR_H
 
#include "Filter.h"
 
namespace stk {
 
/***************************************************/
/***************************************************/
 
class Fir : public Filter
{
public:
  Fir( void );
 
 
  Fir( std::vector<StkFloat> &coefficients );
 
  ~Fir( void );
 
 
  void setCoefficients( std::vector<StkFloat> &coefficients, bool clearState = false );
 
  StkFloat lastOut( void ) const { return lastFrame_[0]; };
 
  StkFloat tick( StkFloat input );
 
 
  StkFrames& tick( StkFrames& frames, unsigned int channel = 0 );
 
 
  StkFrames& tick( StkFrames& iFrames, StkFrames &oFrames, unsigned int iChannel = 0, unsigned int oChannel = 0 );
 
protected:
 
};
 
inline StkFloat Fir :: tick( StkFloat input )
{
  lastFrame_[0] = 0.0;
  inputs_[0] = gain_ * input;
 
  for ( unsigned int i=(unsigned int)(b_.size())-1; i>0; i-- ) {
    lastFrame_[0] += b_[i] * inputs_[i];
    inputs_[i] = inputs_[i-1];
  }
  lastFrame_[0] += b_[0] * inputs_[0];
 
  return lastFrame_[0];
}
 
inline StkFrames& Fir :: tick( StkFrames& frames, unsigned int channel )
{
#if defined(_STK_DEBUG_)
  if ( channel >= frames.channels() ) {
    oStream_ << "Fir::tick(): channel and StkFrames arguments are incompatible!";
    handleError( StkError::FUNCTION_ARGUMENT );
  }
#endif
 
  StkFloat *samples = &frames[channel];
  unsigned int i, hop = frames.channels();
  for ( unsigned int j=0; j<frames.frames(); j++, samples += hop ) {
    inputs_[0] = gain_ * *samples;
    *samples = 0.0;
 
    for ( i=(unsigned int)b_.size()-1; i>0; i-- ) {
      *samples += b_[i] * inputs_[i];
      inputs_[i] = inputs_[i-1];
    }
    *samples += b_[0] * inputs_[0];
  }
 
  lastFrame_[0] = *(samples-hop);
  return frames;
}
 
inline StkFrames& Fir :: tick( StkFrames& iFrames, StkFrames& oFrames, unsigned int iChannel, unsigned int oChannel )
{
#if defined(_STK_DEBUG_)
  if ( iChannel >= iFrames.channels() || oChannel >= oFrames.channels() ) {
    oStream_ << "Fir::tick(): channel and StkFrames arguments are incompatible!";
    handleError( StkError::FUNCTION_ARGUMENT );
  }
#endif
 
  StkFloat *iSamples = &iFrames[iChannel];
  StkFloat *oSamples = &oFrames[oChannel];
  unsigned int i, iHop = iFrames.channels(), oHop = oFrames.channels();
  for ( unsigned int j=0; j<iFrames.frames(); j++, iSamples += iHop, oSamples += oHop ) {
    inputs_[0] = gain_ * *iSamples;
    *oSamples = 0.0;
 
    for ( i=(unsigned int)b_.size()-1; i>0; i-- ) {
      *oSamples += b_[i] * inputs_[i];
      inputs_[i] = inputs_[i-1];
    }
    *oSamples += b_[0] * inputs_[0];
  }
 
  lastFrame_[0] = *(oSamples-oHop);
  return iFrames;
}
 
} // stk namespace
 
#endif