/*

* Portions Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description: 

* The original of this file was released into the public domain, see below for details

*/

/* Notes from RFB: 

   Looks like the user-level routines are:

   Real FFT

   void __ogg_fdrffti(int n, double *wsave, int *ifac)

   void __ogg_fdrfftf(int n,double *r,double *wsave,int *ifac)

   void __ogg_fdrfftb(int n, double *r, double *wsave, int *ifac)

     __ogg_fdrffti == initialization

     __ogg_fdrfftf == forward transform

     __ogg_fdrfftb == backward transform

     Parameters are

     n == length of sequence

     r == sequence to be transformed (input)

       == transformed sequence (output)

     wsave == work array of length 2n (allocated by caller)

     ifac == work array of length 15 (allocated by caller)

   Cosine quarter-wave FFT

   void __ogg_fdcosqi(int n, double *wsave, int *ifac)

   void __ogg_fdcosqf(int n,double *x,double *wsave,int *ifac)

   void __ogg_fdcosqb(int n,double *x,double *wsave,int *ifac)

*/

/********************************************************************

 *                                                                  *

 * THIS FILE IS PART OF THE OggSQUISH SOFTWARE CODEC SOURCE CODE.   *

 *                                                                  *

 ********************************************************************

  file: fft.c

  function: Fast discrete Fourier and cosine transforms and inverses

  author: Monty <xiphmont@mit.edu>

  modifications by: Monty

  last modification date: Jul 1 1996

 ********************************************************************/

/* These Fourier routines were originally based on the Fourier

   routines of the same names from the NETLIB bihar and fftpack

   fortran libraries developed by Paul N. Swarztrauber at the National

   Center for Atmospheric Research in Boulder, CO USA.  They have been

   reimplemented in C and optimized in a few ways for OggSquish. */

/* As the original fortran libraries are public domain, the C Fourier

   routines in this file are hereby released to the public domain as

   well.  The C routines here produce output exactly equivalent to the

   original fortran routines.  Of particular interest are the facts

   that (like the original fortran), these routines can work on

   arbitrary length vectors that need not be powers of two in

   length. */

#include "openc.h"

#define STIN static

static void drfti1(int n, double *wa, int *ifac){

  static int ntryh[4] = { 4,2,3,5 };

  static double tpi = 6.28318530717958647692528676655900577;

  double arg,argh,argld,fi;

  int ntry=0,i,j=-1;

  int k1, l1, l2, ib;

  int ld, ii, ip, is, nq, nr;

  int ido, ipm, nfm1;

  int nl=n;

  int nf=0;

 L101:

  j++;

  if (j < 4)

    ntry=ntryh[j];

  else

    ntry+=2;

 L104:

  nq=nl/ntry;

  nr=nl-ntry*nq;

  if (nr!=0) goto L101;

  nf++;

  ifac[nf+1]=ntry;

  nl=nq;

  if(ntry!=2)goto L107;

  if(nf==1)goto L107;

  for (i=1;i<nf;i++){

    ib=nf-i+1;

    ifac[ib+1]=ifac[ib];

  }

  ifac[2] = 2;

 L107:

  if(nl!=1)goto L104;

  ifac[0]=n;

  ifac[1]=nf;

  argh=tpi/n;

  is=0;

  nfm1=nf-1;

  l1=1;

  if(nfm1==0)return;

  for (k1=0;k1<nfm1;k1++){

    ip=ifac[k1+2];

    ld=0;

    l2=l1*ip;

    ido=n/l2;

    ipm=ip-1;

    for (j=0;j<ipm;j++){

      ld+=l1;

      i=is;

      argld=(double)ld*argh;

      fi=0.;

      for (ii=2;ii<ido;ii+=2){

	fi+=1.;

	arg=fi*argld;

	wa[i++]=cos(arg);

	wa[i++]=sin(arg);

      }

      is+=ido;

    }

    l1=l2;

  }

}

void __ogg_fdrffti(int n, double *wsave, int *ifac){

  if (n == 1) return;

  drfti1(n, wsave+n, ifac);

}

void __ogg_fdcosqi(int n, double *wsave, int *ifac){

  static double pih = 1.57079632679489661923132169163975;

  static int k;

  static double fk, dt;

  dt=pih/n;

  fk=0.;

  for(k=0;k<n;k++){

    fk+=1.;

    wsave[k] = cos(fk*dt);

  }

  __ogg_fdrffti(n, wsave+n,ifac);

}

STIN void dradf2(int ido,int l1,double *cc,double *ch,double *wa1){

  int i,k;

  double ti2,tr2;

  int t0,t1,t2,t3,t4,t5,t6;

  t1=0;

  t0=(t2=l1*ido);

  t3=ido<<1;

  for(k=0;k<l1;k++){

    ch[t1<<1]=cc[t1]+cc[t2];

    ch[(t1<<1)+t3-1]=cc[t1]-cc[t2];

    t1+=ido;

    t2+=ido;

  }

  if(ido<2)return;

  if(ido==2)goto L105;

  t1=0;

  t2=t0;

  for(k=0;k<l1;k++){

    t3=t2;

    t4=(t1<<1)+(ido<<1);

    t5=t1;

    t6=t1+t1;

    for(i=2;i<ido;i+=2){

      t3+=2;

      t4-=2;

      t5+=2;

      t6+=2;

      tr2=wa1[i-2]*cc[t3-1]+wa1[i-1]*cc[t3];

      ti2=wa1[i-2]*cc[t3]-wa1[i-1]*cc[t3-1];

      ch[t6]=cc[t5]+ti2;

      ch[t4]=ti2-cc[t5];

      ch[t6-1]=cc[t5-1]+tr2;

      ch[t4-1]=cc[t5-1]-tr2;

    }

    t1+=ido;

    t2+=ido;

  }

  if(ido%2==1)return;

 L105:

  t3=(t2=(t1=ido)-1);

  t2+=t0;

  for(k=0;k<l1;k++){

    ch[t1]=-cc[t2];

    ch[t1-1]=cc[t3];

    t1+=ido<<1;

    t2+=ido;

    t3+=ido;

  }

}

STIN void dradf4(int ido,int l1,double *cc,double *ch,double *wa1,

	    double *wa2,double *wa3){

  static double hsqt2 = .70710678118654752440084436210485;

  int i,k,t0,t1,t2,t3,t4,t5,t6;

  double ci2,ci3,ci4,cr2,cr3,cr4,ti1,ti2,ti3,ti4,tr1,tr2,tr3,tr4;

  t0=l1*ido;

  t1=t0;

  t4=t1<<1;

  t2=t1+(t1<<1);

  t3=0;

  for(k=0;k<l1;k++){

    tr1=cc[t1]+cc[t2];

    tr2=cc[t3]+cc[t4];

    ch[t5=t3<<2]=tr1+tr2;

    ch[(ido<<2)+t5-1]=tr2-tr1;

    ch[(t5+=(ido<<1))-1]=cc[t3]-cc[t4];

    ch[t5]=cc[t2]-cc[t1];

    t1+=ido;

    t2+=ido;

    t3+=ido;

    t4+=ido;

  }

  if(ido<2)return;

  if(ido==2)goto L105;

  t1=0;

  for(k=0;k<l1;k++){

    t2=t1;

    t4=t1<<2;

    t5=(t6=ido<<1)+t4;

    for(i=2;i<ido;i+=2){

      t3=(t2+=2);

      t4+=2;

      t5-=2;

      t3+=t0;

      cr2=wa1[i-2]*cc[t3-1]+wa1[i-1]*cc[t3];

      ci2=wa1[i-2]*cc[t3]-wa1[i-1]*cc[t3-1];

      t3+=t0;

      cr3=wa2[i-2]*cc[t3-1]+wa2[i-1]*cc[t3];

      ci3=wa2[i-2]*cc[t3]-wa2[i-1]*cc[t3-1];

      t3+=t0;

      cr4=wa3[i-2]*cc[t3-1]+wa3[i-1]*cc[t3];

      ci4=wa3[i-2]*cc[t3]-wa3[i-1]*cc[t3-1];

      tr1=cr2+cr4;

      tr4=cr4-cr2;

      ti1=ci2+ci4;

      ti4=ci2-ci4;

      ti2=cc[t2]+ci3;

      ti3=cc[t2]-ci3;

      tr2=cc[t2-1]+cr3;

      tr3=cc[t2-1]-cr3;

      ch[t4-1]=tr1+tr2;

      ch[t4]=ti1+ti2;

      ch[t5-1]=tr3-ti4;

      ch[t5]=tr4-ti3;

      ch[t4+t6-1]=ti4+tr3;

      ch[t4+t6]=tr4+ti3;

      ch[t5+t6-1]=tr2-tr1;

      ch[t5+t6]=ti1-ti2;

    }

    t1+=ido;

  }

  if(ido%2==1)return;

 L105:

  t2=(t1=t0+ido-1)+(t0<<1);

  t3=ido<<2;

  t4=ido;

  t5=ido<<1;

  t6=ido;

  for(k=0;k<l1;k++){

    ti1=-hsqt2*(cc[t1]+cc[t2]);

    tr1=hsqt2*(cc[t1]-cc[t2]);

    ch[t4-1]=tr1+cc[t6-1];

    ch[t4+t5-1]=cc[t6-1]-tr1;

    ch[t4]=ti1-cc[t1+t0];

    ch[t4+t5]=ti1+cc[t1+t0];

    t1+=ido;

    t2+=ido;

    t4+=t3;

    t6+=ido;

  }

}

STIN void dradfg(int ido,int ip,int l1,int idl1,double *cc,double *c1,

			  double *c2,double *ch,double *ch2,double *wa){

  static double tpi=6.28318530717958647692528676655900577;

  int idij,ipph,i,j,k,l,ic,ik,is;

  int t0,t1,t2,t3,t4,t5,t6,t7,t8,t9,t10;

  double dc2,ai1,ai2,ar1,ar2,ds2;

  int nbd;

  double dcp,arg,dsp,ar1h,ar2h;

  int idp2,ipp2;

  arg=tpi/(double)ip;

  dcp=cos(arg);

  dsp=sin(arg);

  ipph=(ip+1)>>1;

  ipp2=ip;

  idp2=ido;

  nbd=(ido-1)>>1;

  t0=l1*ido;

  t10=ip*ido;

  if(ido==1)goto L119;

  for(ik=0;ik<idl1;ik++)ch2[ik]=c2[ik];

  t1=0;

  for(j=1;j<ip;j++){

    t1+=t0;

    t2=t1;

    for(k=0;k<l1;k++){

      ch[t2]=c1[t2];

      t2+=ido;

    }

  }

  is=-ido;

  t1=0;

  if(nbd>l1){

    for(j=1;j<ip;j++){

      t1+=t0;

      is+=ido;

      t2= -ido+t1;

      for(k=0;k<l1;k++){

	idij=is-1;

	t2+=ido;

	t3=t2;

	for(i=2;i<ido;i+=2){

	  idij+=2;

	  t3+=2;

	  ch[t3-1]=wa[idij-1]*c1[t3-1]+wa[idij]*c1[t3];

	  ch[t3]=wa[idij-1]*c1[t3]-wa[idij]*c1[t3-1];

	}

      }

    }

  }else{

    for(j=1;j<ip;j++){

      is+=ido;

      idij=is-1;

      t1+=t0;

      t2=t1;

      for(i=2;i<ido;i+=2){

	idij+=2;

	t2+=2;

	t3=t2;

	for(k=0;k<l1;k++){

	  ch[t3-1]=wa[idij-1]*c1[t3-1]+wa[idij]*c1[t3];

	  ch[t3]=wa[idij-1]*c1[t3]-wa[idij]*c1[t3-1];

	  t3+=ido;

	}

      }

    }

  }

  t1=0;

  t2=ipp2*t0;

  if(nbd<l1){

    for(j=1;j<ipph;j++){

      t1+=t0;

      t2-=t0;

      t3=t1;

      t4=t2;

      for(i=2;i<ido;i+=2){

	t3+=2;

	t4+=2;

	t5=t3-ido;

	t6=t4-ido;

	for(k=0;k<l1;k++){

	  t5+=ido;

	  t6+=ido;

	  c1[t5-1]=ch[t5-1]+ch[t6-1];

	  c1[t6-1]=ch[t5]-ch[t6];

	  c1[t5]=ch[t5]+ch[t6];

	  c1[t6]=ch[t6-1]-ch[t5-1];

	}

      }

    }

  }else{

    for(j=1;j<ipph;j++){

      t1+=t0;

      t2-=t0;

      t3=t1;

      t4=t2;

      for(k=0;k<l1;k++){

	t5=t3;

	t6=t4;

	for(i=2;i<ido;i+=2){

	  t5+=2;

	  t6+=2;

	  c1[t5-1]=ch[t5-1]+ch[t6-1];

	  c1[t6-1]=ch[t5]-ch[t6];

	  c1[t5]=ch[t5]+ch[t6];

	  c1[t6]=ch[t6-1]-ch[t5-1];

	}

	t3+=ido;

	t4+=ido;

      }

    }

  }

L119:

  for(ik=0;ik<idl1;ik++)c2[ik]=ch2[ik];

  t1=0;

  t2=ipp2*idl1;

  for(j=1;j<ipph;j++){

    t1+=t0;

    t2-=t0;

    t3=t1-ido;

    t4=t2-ido;

    for(k=0;k<l1;k++){

      t3+=ido;

      t4+=ido;

      c1[t3]=ch[t3]+ch[t4];

      c1[t4]=ch[t4]-ch[t3];

    }

  }

  ar1=1.;

  ai1=0.;

  t1=0;

  t2=ipp2*idl1;

  t3=(ip-1)*idl1;

  for(l=1;l<ipph;l++){

    t1+=idl1;

    t2-=idl1;

    ar1h=dcp*ar1-dsp*ai1;

    ai1=dcp*ai1+dsp*ar1;

    ar1=ar1h;

    t4=t1;

    t5=t2;

    t6=t3;

    t7=idl1;

    for(ik=0;ik<idl1;ik++){

      ch2[t4++]=c2[ik]+ar1*c2[t7++];

      ch2[t5++]=ai1*c2[t6++];

    }

    dc2=ar1;

    ds2=ai1;

    ar2=ar1;

    ai2=ai1;

    t4=idl1;

    t5=(ipp2-1)*idl1;

    for(j=2;j<ipph;j++){

      t4+=idl1;

      t5-=idl1;

      ar2h=dc2*ar2-ds2*ai2;

      ai2=dc2*ai2+ds2*ar2;

      ar2=ar2h;

      t6=t1;

      t7=t2;

      t8=t4;

      t9=t5;

      for(ik=0;ik<idl1;ik++){

	ch2[t6++]+=ar2*c2[t8++];

	ch2[t7++]+=ai2*c2[t9++];

      }

    }

  }

  t1=0;

  for(j=1;j<ipph;j++){

    t1+=idl1;

    t2=t1;

    for(ik=0;ik<idl1;ik++)ch2[ik]+=c2[t2++];

  }

  if(ido<l1)goto L132;

  t1=0;

  t2=0;

  for(k=0;k<l1;k++){

    t3=t1;

    t4=t2;

    for(i=0;i<ido;i++)cc[t4++]=ch[t3++];

    t1+=ido;

    t2+=t10;

  }

  goto L135;

 L132:

  for(i=0;i<ido;i++){

    t1=i;

    t2=i;