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/*
* bfft.c - Code for some fourrier transform variants and utility
* functions. Data organization is in (real, imag) pairs the first 2
* components are (DC, NY)
*
* Copyright (c) 2000-2003 by Tom Schouten
*
* Restructured code to separate objects and library blob mode
* Fred Jan Kraan, 2020-01-12
*
* 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "m_pd.h"
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#define MAXORDER 64
typedef struct bfftctl
{
int c_levels;
char c_name[16];
int *c_clutter;
int *c_unclutter;
int c_kill_DC;
int c_kill_NY;
} t_bfftctl;
typedef struct bfft
{
t_object x_obj;
t_float x_f;
t_bfftctl x_ctl;
} t_bfft;
t_class *bfft_class, *ibfft_class, *fht_class;
static inline void bfft_perform_permutation(t_float *S, int n, int *f)
{
int k,l;
t_float swap;
for(k=0; k<n; k++)
{
l = f[k];
while (l<k) l = f[l];
swap = S[k];
S[k] = S[l];
S[l] = swap;
}
}
static void bfft_permutation(t_bfft *x, int n){
t_bfftctl *ctl = &x->x_ctl;
int i;
if (ctl->c_clutter) free(ctl->c_clutter);
if (ctl->c_unclutter) free(ctl->c_unclutter);
ctl->c_clutter = (int *)malloc(n*sizeof(int));
ctl->c_unclutter = (int *)malloc(n*sizeof(int));
ctl->c_unclutter[0] = 0;
ctl->c_unclutter[1] = n/2;
for (i=1; i<n/2; i++){
ctl->c_unclutter[2*i] = i;
ctl->c_unclutter[2*i+1] = n-i;
}
for(i=0; i<n; i++)
ctl->c_clutter[ctl->c_unclutter[i]] = i;
return;
/* debug */
/* for(k=0; k<n; k++)
** printf("clutter[%d] = %d\n", k, ctl->c_clutter[k]);
** for(k=0; k<n; k++)
** printf("unclutter[%d] = %d\n", k, ctl->c_unclutter[k]);
**
** exit(1);
*/
}
static t_int *bfft_perform(t_int *w)
{
// t_float *in = (t_float *)(w[3]);
t_float *out = (t_float *)(w[4]);
t_bfftctl *ctl = (t_bfftctl *)(w[1]);
int n = (int)(w[2]);
t_float scale = sqrt(1.0f / (t_float)(n));
mayer_fht(out, n);
bfft_perform_permutation(out, n, ctl->c_unclutter);
while (n--) *out++ *= scale;
return (w+5);
}
static void bfft_dsp(t_bfft *x, t_signal **sp)
{
int n = sp[0]->s_n;
t_float *in = sp[0]->s_vec;
t_float *out = sp[1]->s_vec;
bfft_permutation(x, n);
if (in != out)
{
dsp_add_copy(in, out, n);
in = out;
}
dsp_add(bfft_perform, 4, &x->x_ctl, n, in, out);
}
static void bfft_free(t_bfft *x)
{
if (x->x_ctl.c_clutter) free(x->x_ctl.c_clutter);
if (x->x_ctl.c_unclutter) free(x->x_ctl.c_unclutter);
}
static void *bfft_new(void)
{
t_bfft *x = (t_bfft *)pd_new(bfft_class);
outlet_new(&x->x_obj, gensym("signal"));
sprintf(x->x_ctl.c_name,"bfft");
x->x_ctl.c_clutter = NULL;
x->x_ctl.c_unclutter = NULL;
return (void *)x;
}
void bfft_tilde_setup(void)
{
//post("bfft~ v0.1");
bfft_class = class_new(gensym("bfft~"), (t_newmethod)bfft_new,
(t_method)bfft_free, sizeof(t_bfft), 0, 0);
CLASS_MAINSIGNALIN(bfft_class, t_bfft, x_f);
class_addmethod(bfft_class, (t_method)bfft_dsp, gensym("dsp"), 0);
}
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