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/*
eqfil.c:
Copyright (C) 2007 Victor Lazzarini
This file is part of Csound.
The Csound Library is free software; you can redistribute it
and/or modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
Csound 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 Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with Csound; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
02110-1301 USA
*/
// #include "csdl.h"
#include "csoundCore.h"
#include "interlocks.h"
typedef struct _equ {
OPDS h;
MYFLT *out;
MYFLT *sig, *fr, *bw, *g, *ini; /* in, freq, bw, gain, ini */
double z1,z2; /* delay memory */
MYFLT frv, bwv; /* bandwidth and frequency */
double c,d; /* filter vars */
} equ;
static int32_t equ_init(CSOUND *csound, equ *p)
{
if (*p->ini==0) {
double sr = (double)CS_ESR;
p->z1 = p->z2 = 0.0;
p->frv = *p->fr; p->bwv = *p->bw;
p->d = cos(2*PI*p->frv/sr);
p->c = tan(PI*p->bwv/sr);
}
return OK;
}
static int32_t equ_process(CSOUND *csound, equ *p)
{
double z1 = p->z1, z2 = p->z2,c,d,w,a,y;
MYFLT *in= p->sig,*out=p->out,g;
uint32_t offset = p->h.insdshead->ksmps_offset;
uint32_t early = p->h.insdshead->ksmps_no_end;
int32_t
i, ksmps = CS_KSMPS;
if (*p->bw != p->bwv || *p->fr != p->frv){
double sr = (double)CS_ESR;
p->frv = *p->fr; p->bwv = *p->bw;
p->d = cos(2*PI*p->frv/sr);
p->c = tan(PI*p->bwv/sr);
}
c = p->c;
d = p->d;
a = (1.0-c)/(1.0+c);
g = *p->g;
if (UNLIKELY(offset)) memset(out, '\0', offset*sizeof(MYFLT));
if (UNLIKELY(early)) {
ksmps -= early;
memset(&out[ksmps], '\0', early*sizeof(MYFLT));
}
for (i=0; i < ksmps; i++){
w = (double)(in[i]) + d*(1.0 + a)*z1 - a*z2;
y = w*a - d*(1.0 + a)*z1 + z2;
z2 = z1;
z1 = w;
out[i] = (MYFLT) (0.5*(y + in[i] + g*(in[i] - y)));
}
p->z1 = z1;
p->z2 = z2;
return OK;
}
static OENTRY eqfil_localops[] = {
{"eqfil", sizeof(equ), 0, 3,
"a", "akkko", (SUBR)equ_init, (SUBR)equ_process},
};
LINKAGE_BUILTIN(eqfil_localops)
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