/*
 * $ProjectName$
 * $ProjectRevision$
 * -----------------------------------------------------------
 * $Id$
 * -----------------------------------------------------------
 *
 * $Author$
 *
 * Description:
 *
 * Copyright 2002-2003 Tor-Einar Jarnbjo
 * -----------------------------------------------------------
 *
 * Change History
 * -----------------------------------------------------------
 * $Log$
 * Revision 1.1  2005/07/11 15:42:36  hcl
 * Songdb java version, source. only 1.5 compatible
 *
 * Revision 1.2  2004/09/21 12:09:45  shred
 * *** empty log message ***
 *
 * Revision 1.1.1.1  2004/04/04 22:09:12  shred
 * First Import
 *
 * Revision 1.3  2003/04/10 19:49:04  jarnbjo
 * no message
 *
 * Revision 1.2  2003/03/16 01:11:12  jarnbjo
 * no message
 *
 *
 */

package de.jarnbjo.vorbis;

class MdctFloat {
  static private final float cPI3_8=0.38268343236508977175f;
  static private final float cPI2_8=0.70710678118654752441f;
  static private final float cPI1_8=0.92387953251128675613f;

  private int n;
  private int log2n;

  private float[] trig;
  private int[] bitrev;

  private float[] equalizer;

  private float scale;

  private int itmp1, itmp2, itmp3, itmp4, itmp5, itmp6, itmp7, itmp8, itmp9;
  private float dtmp1, dtmp2, dtmp3, dtmp4, dtmp5, dtmp6, dtmp7, dtmp8, dtmp9;

  protected MdctFloat(int n) {
    bitrev=new int[n/4];
    trig=new float[n+n/4];

    int n2=n>>>1;
    log2n=(int)Math.rint(Math.log(n)/Math.log(2));
    this.n=n;

    int AE=0;
    int AO=1;
    int BE=AE+n/2;
    int BO=BE+1;
    int CE=BE+n/2;
    int CO=CE+1;
    // trig lookups...
    for(int i=0;i<n/4;i++){
      trig[AE+i*2]=(float)Math.cos((Math.PI/n)*(4*i));
      trig[AO+i*2]=(float)-Math.sin((Math.PI/n)*(4*i));
      trig[BE+i*2]=(float)Math.cos((Math.PI/(2*n))*(2*i+1));
      trig[BO+i*2]=(float)Math.sin((Math.PI/(2*n))*(2*i+1));
    }
    for(int i=0;i<n/8;i++){
      trig[CE+i*2]=(float)Math.cos((Math.PI/n)*(4*i+2));
      trig[CO+i*2]=(float)-Math.sin((Math.PI/n)*(4*i+2));
    }

    {
      int mask=(1<<(log2n-1))-1;
      int msb=1<<(log2n-2);
      for(int i=0;i<n/8;i++){
  int acc=0;
  for(int j=0;msb>>>j!=0;j++)
    if(((msb>>>j)&i)!=0)acc|=1<<j;
  bitrev[i*2]=((~acc)&mask);
//  bitrev[i*2]=((~acc)&mask)-1;
  bitrev[i*2+1]=acc;
      }
    }
    scale=4.f/n;
  }

  //void clear(){
  //}

  //void forward(float[] in, float[] out){
  //}

   private float[] _x=new float[1024];
   private float[] _w=new float[1024];

   protected void setEqualizer(float[] equalizer) {
      this.equalizer=equalizer;
   }

   protected float[] getEqualizer() {
      return equalizer;
   }

   protected synchronized void imdct(final float[] frq, final float[] window, final int[] pcm) {//, float[] out){

      float[] in=frq;//, out=buf;
      if(_x.length<n/2){_x=new float[n/2];}
      if(_w.length<n/2){_w=new float[n/2];}
      final float[] x=_x;
      final float[] w=_w;
      int n2=n>>1;
      int n4=n>>2;
      int n8=n>>3;

      if(equalizer!=null) {
         for(int i=0; i<n; i++) {
            frq[i]*=equalizer[i];
         }
      }

      // rotate + step 1
      {
         int inO=-1;
         int xO=0;
         int A=n2;

         int i;
         for(i=0;i<n8;i++) {
            dtmp1=in[inO+=2];
            dtmp2=in[inO+=2];
            dtmp3=trig[--A];
            dtmp4=trig[--A];
           x[xO++]=-dtmp2*dtmp3 - dtmp1*dtmp4;
           x[xO++]= dtmp1*dtmp3 - dtmp2*dtmp4;
           //A-=2;
           //x[xO++]=-in[inO+2]*trig[A+1] - in[inO]*trig[A];
           //x[xO++]= in[inO]*trig[A+1] - in[inO+2]*trig[A];
           //inO+=4;
         }

         inO=n2;//-4;

         for(i=0;i<n8;i++) {
            dtmp1=in[inO-=2];
            dtmp2=in[inO-=2];
            dtmp3=trig[--A];
            dtmp4=trig[--A];
           x[xO++]=dtmp2*dtmp3 + dtmp1*dtmp4;
           x[xO++]=dtmp2*dtmp4 - dtmp1*dtmp3;
           //A-=2;
           //x[xO++]=in[inO]*trig[A+1] + in[inO+2]*trig[A];
           //x[xO++]=in[inO]*trig[A] - in[inO+2]*trig[A+1];
           //inO-=4;
         }
      }

      float[] xxx=kernel(x,w,n,n2,n4,n8);
      int xx=0;

      // step 8

      {
         int B=n2;
         int o1=n4,o2=o1-1;
         int o3=n4+n2,o4=o3-1;

         for(int i=0;i<n4;i++){
            dtmp1=xxx[xx++];
            dtmp2=xxx[xx++];
            dtmp3=trig[B++];
            dtmp4=trig[B++];

           float temp1= (dtmp1* dtmp4 - dtmp2 * dtmp3);
           float temp2=-(dtmp1 * dtmp3 + dtmp2 * dtmp4);

            /*
           float temp1= (xxx[xx] * trig[B+1] - xxx[xx+1] * trig[B]);//*32767.0f;
           float temp2=-(xxx[xx] * trig[B] + xxx[xx+1] * trig[B+1]);//*32767.0f;
            */

            //if(temp1>32767.0f) temp1=32767.0f;
            //if(temp1<-32768.0f) temp1=-32768.0f;
            //if(temp2>32767.0f) temp2=32767.0f;
            //if(temp2<-32768.0f) temp2=-32768.0f;

           pcm[o1]=(int)(-temp1*window[o1]);
           pcm[o2]=(int)( temp1*window[o2]);
           pcm[o3]=(int)( temp2*window[o3]);
           pcm[o4]=(int)( temp2*window[o4]);

           o1++;
           o2--;
           o3++;
           o4--;
           //xx+=2;
           //B+=2;
         }
      }
   }

   private float[] kernel(float[] x, float[] w,
                         int n, int n2, int n4, int n8){
      // step 2

      int xA=n4;
      int xB=0;
      int w2=n4;
      int A=n2;

      for(int i=0;i<n4;){
         float x0=x[xA] - x[xB];
         float x1;
         w[w2+i]=x[xA++]+x[xB++];

         x1=x[xA]-x[xB];
         A-=4;

         w[i++]=   x0 * trig[A] + x1 * trig[A+1];
         w[i]=     x1 * trig[A] - x0 * trig[A+1];

         w[w2+i]=x[xA++]+x[xB++];
         i++;
      }

      // step 3

      {
         for(int i=0;i<log2n-3;i++){
            int k0=n>>>(i+2);
           int k1=1<<(i+3);
           int wbase=n2-2;

           A=0;
           float[] temp;

           for(int r=0;r<(k0>>>2);r++){
               int w1=wbase;
               w2=w1-(k0>>1);
               float AEv= trig[A],wA;
               float AOv= trig[A+1],wB;
               wbase-=2;

               k0++;
               for(int s=0;s<(2<<i);s++){
                  dtmp1=w[w1];
                  dtmp2=w[w2];
                  wB=dtmp1-dtmp2;
                  x[w1]=dtmp1+dtmp2;
                  dtmp1=w[++w1];
                  dtmp2=w[++w2];
                  wA=dtmp1-dtmp2;
                  x[w1]=dtmp1+dtmp2;
                  x[w2]  =wA*AEv  - wB*AOv;
                  x[w2-1]=wB*AEv  + wA*AOv;

                  /*
                  wB     =w[w1]   -w[w2];
                  x[w1]  =w[w1]   +w[w2];

                  wA     =w[++w1] -w[++w2];
                  x[w1]  =w[w1]   +w[w2];

                  x[w2]  =wA*AEv  - wB*AOv;
                  x[w2-1]=wB*AEv  + wA*AOv;
                  */

                  w1-=k0;
                  w2-=k0;
              }
              k0--;
              A+=k1;
           }

           temp=w;
           w=x;
           x=temp;
         }
      }

      // step 4, 5, 6, 7
      {
         int C=n;
         int bit=0;
         int x1=0;
         int x2=n2-1;

         for(int i=0;i<n8;i++) {
            int t1=bitrev[bit++];
            int t2=bitrev[bit++];

            float wA=w[t1]-w[t2+1];
            float wB=w[t1-1]+w[t2];
            float wC=w[t1]+w[t2+1];
            float wD=w[t1-1]-w[t2];

            float wACE=wA* trig[C];
            float wBCE=wB* trig[C++];
            float wACO=wA* trig[C];
            float wBCO=wB* trig[C++];

            x[x1++]=( wC+wACO+wBCE)*16383.0f;
            x[x2--]=(-wD+wBCO-wACE)*16383.0f;
            x[x1++]=( wD+wBCO-wACE)*16383.0f;
            x[x2--]=( wC-wACO-wBCE)*16383.0f;
         }
      }
      return x;
   }

}