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/*
* DCblock
*
* This code has been extracted from the Csound opcode "dcblock".
* It has been modified to work as a Soundpipe module.
*
* Original Author(s): Perry R. Cook
* Year: 1995
* Location: Opcodes/biquad.c
*
*/
#include <math.h>
#include <stdlib.h>
#include "base.h"
#include "dcblock.h"
int sp_dcblock_create(sp_dcblock **p)
{
*p = malloc(sizeof(sp_dcblock));
return SP_OK;
}
int sp_dcblock_destroy(sp_dcblock **p)
{
free(*p);
return SP_OK;
}
int sp_dcblock_init(sp_data *sp, sp_dcblock *p, int oversampling )
{
p->outputs = 0.0;
p->inputs = 0.0;
p->gain = pow( 0.99, 1.0f / oversampling );
if (p->gain == 0.0 || p->gain>=1.0 || p->gain<=-1.0)
p->gain = 0.99;
return SP_OK;
}
int sp_dcblock_compute(sp_data *sp, sp_dcblock *p, SPFLOAT *in, SPFLOAT *out)
{
SPFLOAT gain = p->gain;
SPFLOAT outputs = p->outputs;
SPFLOAT inputs = p->inputs;
SPFLOAT sample = *in;
outputs = sample - inputs + (gain * outputs);
inputs = sample;
*out = outputs;
p->outputs = outputs;
p->inputs = inputs;
return SP_OK;
}
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