filter_code.h

/*
Copyright (C) 2019 BrerDawg

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
*/

//filter_code.h
//v1.02

#ifndef filter_code_h
#define filter_code_h

#include <stdio.h>
#include <string.h>
#include <string>
#include <wchar.h>
#include <math.h>
#include <vector>
#include <complex>

#include "globals.h"
#include "GCProfile.h"
#include "mgraph.h"
#include "audio_formats.h"


using namespace std;



#define cn_filter_tap_limit 16384


enum en_filter_pass_type_tag
{
fpt_undefined,
fpt_lowpass,
fpt_highpass,
fpt_bandpass,

fpt_notch,

fpt_bandpass2,                  //use by: filter_iir_2nd_order(..)
fpt_apf,
fpt_peakeq,
fpt_lowshelf,
fpt_highshelf,
};








//refer http://www.mikroe.com/chapters/view/72/chapter-2-fir-filters/
enum en_filter_window_type_tag
{
fwt_undefined,
fwt_rect,
fwt_kaiser,                     //not yet supported
fwt_bartlett,
fwt_hann,
fwt_bartlett_hanning,
fwt_hamming,
//fwt_bohman,                   //not yet supported
fwt_blackman,
fwt_blackman_harris,
fwt_lanczos1,
fwt_lanczos1_5,
fwt_lanczos2,
fwt_lanczos3,
};







struct st_cplex_tag
{
double real;
double imag;
};



typedef struct 
{
bool created;
int coeff_cnt;
double *coeff_ptr;
double *prev;
unsigned int prev_idx;
bool bypass;

} st_fir;






/* v1.02
typedef struct 
{
bool created;
int coeff_cnt;
double *coeff_ptr;
double *prev;
unsigned int prev_idx;
bool bypass;

} st_iir;
*/



//v1.02
struct st_iir_2nd_order_tag
{
bool bypass;
float coeff[5];															//a1, a2, b0, b1, b2
float delay0[2];														//for ch0
float delay1[2];														//for ch1
};







//function prototypes
bool calc_filter_iir_2nd_order( en_filter_pass_type_tag filt_type, double fc1, double in_Q, double db_gain, double srate, vector<double> &vcoeff );
bool filter_iir_2nd_order( vector <st_cplex_tag> &viq, double a1, double a2, double b0,  double b1, double b2, double &d0r, double &d1r, double &d0i, double &d1i );
bool filter_fir_windowed( en_filter_window_type_tag   wnd_type, en_filter_pass_type_tag   filt_type, unsigned int taps, double fc1, double fc2, double srate, vector<double> &vcoeff );
bool read_iowa_hills_coeffs( string fname, int section, double &a1, double &a2, double &b0, double &b1, double &b2 );


void fir_init( st_fir &fir );
void fir_in( st_fir &fir, double in );
double fir_out( st_fir &fir );
//double fir_out_inline_4( st_fir &fir );
//double fir_out_inline_8( st_fir &fir );
bool create_filter_from_coeffs( st_fir &fir, vector<double> &vcoeff );
void delete_filter( st_fir &fir );

bool create_filter_from_string( st_fir &fir, string scoeff );
bool create_filter_from_file( st_fir &fir, string fname );

//void filter_iir_2nd_order_slow( double &dsignal, double a1, double a2, double b0,  double b1, double b2, double &d0, double &d1 );
void filter_iir_2nd_order( float &fsignal, st_iir_2nd_order_tag &of );	//v1.02
void filter_iir_2nd_order_2ch( float &fsig0, float &fsig1, st_iir_2nd_order_tag &of );	//v1.02




#endif