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diff --git a/lib/iir.c b/lib/iir.c
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-/********************************************************************
- * *
- * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE. *
- * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS *
- * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
- * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. *
- * *
- * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2001 *
- * by the XIPHOPHORUS Company http://www.xiph.org/ *
-
- ********************************************************************
-
- function: Direct Form II IIR filters, plus some specializations
- last mod: $Id: iir.c,v 1.10 2001/02/26 03:50:41 xiphmont Exp $
-
- ********************************************************************/
-
-/* LPC is actually a degenerate case of form I/II filters, but we need
- both */
-
-#include <ogg/ogg.h>
-#include <stdlib.h>
-#include <string.h>
-#include <math.h>
-#include "iir.h"
-
-void IIR_init(IIR_state *s,int stages,float gain, float *A, float *B){
- memset(s,0,sizeof(IIR_state));
- s->stages=stages;
- s->gain=1.f/gain;
- s->coeff_A=_ogg_malloc(stages*sizeof(float));
- s->coeff_B=_ogg_malloc((stages+1)*sizeof(float));
- s->z_A=_ogg_calloc(stages*2,sizeof(float));
-
- memcpy(s->coeff_A,A,stages*sizeof(float));
- memcpy(s->coeff_B,B,(stages+1)*sizeof(float));
-}
-
-void IIR_clear(IIR_state *s){
- if(s){
- _ogg_free(s->coeff_A);
- _ogg_free(s->coeff_B);
- _ogg_free(s->z_A);
- memset(s,0,sizeof(IIR_state));
- }
-}
-
-void IIR_reset(IIR_state *s){
- memset(s->z_A,0,sizeof(float)*s->stages*2);
-}
-
-float IIR_filter(IIR_state *s,float in){
- int stages=s->stages,i;
- float newA= in*s->gain;
- float newB=0;
- float *zA=s->z_A+s->ring;
-
- for(i=0;i<stages;i++){
- newA+= s->coeff_A[i] * zA[i];
- newB+= s->coeff_B[i] * zA[i];
- }
- newB+=newA*s->coeff_B[stages];
-
- zA[0]=zA[stages]=newA;
- if(++s->ring>=stages)s->ring=0;
- return(newB);
-}
-
-/* this assumes the symmetrical structure of the feed-forward stage of
- a typical bandpass to save multiplies */
-float IIR_filter_Band(IIR_state *s,float in){
- int stages=s->stages,i;
- int stages2=stages>>1;
- float newA= in*s->gain;
- float newB=0;
- float *zA=s->z_A+s->ring;
-
- newA+= s->coeff_A[0] * zA[0];
- for(i=1;i<stages2;i++){
- newA+= s->coeff_A[i] * zA[i];
- newB+= s->coeff_B[i] * (zA[i]-zA[stages-i]);
- }
- newB+= s->coeff_B[i] * zA[i];
- for(;i<stages;i++)
- newA+= s->coeff_A[i] * zA[i];
-
- newB+=newA-zA[0];
-
- zA[0]=zA[stages]=newA;
- if(++s->ring>=stages)s->ring=0;
- return(newB);
-}
-
-#ifdef _V_SELFTEST
-
-/* z^-stage, z^-stage+1... */
-static float cheb_bandpass_B[]={-1.f,0.f,5.f,0.f,-10.f,0.f,10.f,0.f,-5.f,0.f,1f};
-static float cheb_bandpass_A[]={-0.6665900311f,
- 1.0070146601f,
- -3.1262875409f,
- 3.5017171569f,
- -6.2779211945f,
- 5.2966481740f,
- -6.7570216587f,
- 4.0760335768f,
- -3.9134284363f,
- 1.3997338886f};
-
-static float data[128]={
- 0.0426331f,
- 0.0384521f,
- 0.0345764f,
- 0.0346069f,
- 0.0314636f,
- 0.0310059f,
- 0.0318604f,
- 0.0336304f,
- 0.036438f,
- 0.0348511f,
- 0.0354919f,
- 0.0343628f,
- 0.0325623f,
- 0.0318909f,
- 0.0263367f,
- 0.0225525f,
- 0.0195618f,
- 0.0160828f,
- 0.0168762f,
- 0.0145569f,
- 0.0126343f,
- 0.0127258f,
- 0.00820923f,
- 0.00787354f,
- 0.00558472f,
- 0.00204468f,
- 3.05176e-05f,
- -0.00357056f,
- -0.00570679f,
- -0.00991821f,
- -0.0101013f,
- -0.00881958f,
- -0.0108948f,
- -0.0110168f,
- -0.0119324f,
- -0.0161438f,
- -0.0194702f,
- -0.0229187f,
- -0.0260315f,
- -0.0282288f,
- -0.0306091f,
- -0.0330505f,
- -0.0364685f,
- -0.0385742f,
- -0.0428772f,
- -0.043457f,
- -0.0425415f,
- -0.0462341f,
- -0.0467529f,
- -0.0489807f,
- -0.0520325f,
- -0.0558167f,
- -0.0596924f,
- -0.0591431f,
- -0.0612793f,
- -0.0618591f,
- -0.0615845f,
- -0.0634155f,
- -0.0639648f,
- -0.0683594f,
- -0.0718079f,
- -0.0729675f,
- -0.0791931f,
- -0.0860901f,
- -0.0885315f,
- -0.088623f,
- -0.089386f,
- -0.0899353f,
- -0.0886841f,
- -0.0910645f,
- -0.0948181f,
- -0.0919495f,
- -0.0891418f,
- -0.0916443f,
- -0.096344f,
- -0.100464f,
- -0.105499f,
- -0.108612f,
- -0.112213f,
- -0.117676f,
- -0.120911f,
- -0.124329f,
- -0.122162f,
- -0.120605f,
- -0.12326f,
- -0.12619f,
- -0.128998f,
- -0.13205f,
- -0.134247f,
- -0.137939f,
- -0.143555f,
- -0.14389f,
- -0.14859f,
- -0.153717f,
- -0.159851f,
- -0.164551f,
- -0.162811f,
- -0.164276f,
- -0.156952f,
- -0.140564f,
- -0.123291f,
- -0.10321f,
- -0.0827637f,
- -0.0652466f,
- -0.053772f,
- -0.0509949f,
- -0.0577698f,
- -0.0818176f,
- -0.114929f,
- -0.148895f,
- -0.181122f,
- -0.200714f,
- -0.21048f,
- -0.203644f,
- -0.179413f,
- -0.145325f,
- -0.104492f,
- -0.0658264f,
- -0.0332031f,
- -0.0106201f,
- -0.00363159f,
- -0.00909424f,
- -0.0244141f,
- -0.0422058f,
- -0.0537415f,
- -0.0610046f,
- -0.0609741f,
- -0.0547791f};
-
-/* comparison test code from http://www-users.cs.york.ac.uk/~fisher/mkfilter/
- (the above page kicks ass, BTW)*/
-
-#define NZEROS 10
-#define NPOLES 10
-#define GAIN 4.599477515e+02f
-
-static float xv[NZEROS+1], yv[NPOLES+1];
-
-static float filterloop(float next){
- xv[0] = xv[1]; xv[1] = xv[2]; xv[2] = xv[3]; xv[3] = xv[4]; xv[4] = xv[5];
- xv[5] = xv[6]; xv[6] = xv[7]; xv[7] = xv[8]; xv[8] = xv[9]; xv[9] = xv[10];
- xv[10] = next / GAIN;
- yv[0] = yv[1]; yv[1] = yv[2]; yv[2] = yv[3]; yv[3] = yv[4]; yv[4] = yv[5];
- yv[5] = yv[6]; yv[6] = yv[7]; yv[7] = yv[8]; yv[8] = yv[9]; yv[9] = yv[10];
- yv[10] = (xv[10] - xv[0]) + 5 * (xv[2] - xv[8]) + 10 * (xv[6] - xv[4])
- + ( -0.6665900311f * yv[0]) + ( 1.0070146601f * yv[1])
- + ( -3.1262875409f * yv[2]) + ( 3.5017171569f * yv[3])
- + ( -6.2779211945f * yv[4]) + ( 5.2966481740f * yv[5])
- + ( -6.7570216587f * yv[6]) + ( 4.0760335768f * yv[7])
- + ( -3.9134284363f * yv[8]) + ( 1.3997338886f * yv[9]);
- return(yv[10]);
-}
-
-#include <stdio.h>
-int main(){
-
- /* run the pregenerated Chebyshev filter, then our own distillation
- through the generic and specialized code */
- float *work=_ogg_malloc(128*sizeof(float));
- IIR_state iir;
- int i;
-
- for(i=0;i<128;i++)work[i]=filterloop(data[i]);
- {
- FILE *out=fopen("IIR_ref.m","w");
- for(i=0;i<128;i++)fprintf(out,"%g\n",work[i]);
- fclose(out);
- }
-
- IIR_init(&iir,NPOLES,GAIN,cheb_bandpass_A,cheb_bandpass_B);
- for(i=0;i<128;i++)work[i]=IIR_filter(&iir,data[i]);
- {
- FILE *out=fopen("IIR_gen.m","w");
- for(i=0;i<128;i++)fprintf(out,"%g\n",work[i]);
- fclose(out);
- }
- IIR_clear(&iir);
-
- IIR_init(&iir,NPOLES,GAIN,cheb_bandpass_A,cheb_bandpass_B);
- for(i=0;i<128;i++)work[i]=IIR_filter_ChebBand(&iir,data[i]);
- {
- FILE *out=fopen("IIR_cheb.m","w");
- for(i=0;i<128;i++)fprintf(out,"%g\n",work[i]);
- fclose(out);
- }
- IIR_clear(&iir);
-
- return(0);
-}
-
-#endif
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