/usr/include/stk/OnePole.h is in libstk0-dev 4.4.4-4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 | #ifndef STK_ONEPOLE_H
#define STK_ONEPOLE_H
#include "Filter.h"
namespace stk {
/***************************************************/
/*! \class OnePole
\brief STK one-pole filter class.
This class implements a one-pole digital filter. A method is
provided for setting the pole position along the real axis of the
z-plane while maintaining a constant peak filter gain.
by Perry R. Cook and Gary P. Scavone, 1995-2012.
*/
/***************************************************/
class OnePole : public Filter
{
public:
//! The default constructor creates a low-pass filter (pole at z = 0.9).
OnePole( StkFloat thePole = 0.9 );
//! Class destructor.
~OnePole();
//! Set the b[0] coefficient value.
void setB0( StkFloat b0 ) { b_[0] = b0; };
//! Set the a[1] coefficient value.
void setA1( StkFloat a1 ) { a_[1] = a1; };
//! Set all filter coefficients.
void setCoefficients( StkFloat b0, StkFloat a1, bool clearState = false );
//! Set the pole position in the z-plane.
/*!
This method sets the pole position along the real-axis of the
z-plane and normalizes the coefficients for a maximum gain of one.
A positive pole value produces a low-pass filter, while a negative
pole value produces a high-pass filter. This method does not
affect the filter \e gain value. The argument magnitude should be
less than one to maintain filter stability.
*/
void setPole( StkFloat thePole );
//! Return the last computed output value.
StkFloat lastOut( void ) const { return lastFrame_[0]; };
//! Input one sample to the filter and return one output.
StkFloat tick( StkFloat input );
//! Take a channel of the StkFrames object as inputs to the filter and replace with corresponding outputs.
/*!
The StkFrames argument reference is returned. The \c channel
argument must be less than the number of channels in the
StkFrames argument (the first channel is specified by 0).
However, range checking is only performed if _STK_DEBUG_ is
defined during compilation, in which case an out-of-range value
will trigger an StkError exception.
*/
StkFrames& tick( StkFrames& frames, unsigned int channel = 0 );
//! Take a channel of the \c iFrames object as inputs to the filter and write outputs to the \c oFrames object.
/*!
The \c iFrames object reference is returned. Each channel
argument must be less than the number of channels in the
corresponding StkFrames argument (the first channel is specified
by 0). However, range checking is only performed if _STK_DEBUG_
is defined during compilation, in which case an out-of-range value
will trigger an StkError exception.
*/
StkFrames& tick( StkFrames& iFrames, StkFrames &oFrames, unsigned int iChannel = 0, unsigned int oChannel = 0 );
};
inline StkFloat OnePole :: tick( StkFloat input )
{
inputs_[0] = gain_ * input;
lastFrame_[0] = b_[0] * inputs_[0] - a_[1] * outputs_[1];
outputs_[1] = lastFrame_[0];
return lastFrame_[0];
}
inline StkFrames& OnePole :: tick( StkFrames& frames, unsigned int channel )
{
#if defined(_STK_DEBUG_)
if ( channel >= frames.channels() ) {
oStream_ << "OnePole::tick(): channel and StkFrames arguments are incompatible!";
handleError( StkError::FUNCTION_ARGUMENT );
}
#endif
StkFloat *samples = &frames[channel];
unsigned int hop = frames.channels();
for ( unsigned int i=0; i<frames.frames(); i++, samples += hop ) {
inputs_[0] = gain_ * *samples;
*samples = b_[0] * inputs_[0] - a_[1] * outputs_[1];
outputs_[1] = *samples;
}
lastFrame_[0] = outputs_[1];
return frames;
}
inline StkFrames& OnePole :: tick( StkFrames& iFrames, StkFrames& oFrames, unsigned int iChannel, unsigned int oChannel )
{
#if defined(_STK_DEBUG_)
if ( iChannel >= iFrames.channels() || oChannel >= oFrames.channels() ) {
oStream_ << "OnePole::tick(): channel and StkFrames arguments are incompatible!";
handleError( StkError::FUNCTION_ARGUMENT );
}
#endif
StkFloat *iSamples = &iFrames[iChannel];
StkFloat *oSamples = &oFrames[oChannel];
unsigned int iHop = iFrames.channels(), oHop = oFrames.channels();
for ( unsigned int i=0; i<iFrames.frames(); i++, iSamples += iHop, oSamples += oHop ) {
inputs_[0] = gain_ * *iSamples;
*oSamples = b_[0] * inputs_[0] - a_[1] * outputs_[1];
outputs_[1] = *oSamples;
}
lastFrame_[0] = outputs_[1];
return iFrames;
}
} // stk namespace
#endif
|