floor1.c

fix point版本的Ogg Vorbis decoder

	TO_FIXP(30,2.8133190e-06F), TO_FIXP(30,2.9961443e-06F), 
	TO_FIXP(30,3.1908506e-06F), TO_FIXP(30,3.3982101e-06F),
	TO_FIXP(30,3.6190449e-06F), TO_FIXP(30,3.8542308e-06F), 
	TO_FIXP(30,4.1047004e-06F), TO_FIXP(30,4.3714470e-06F),
	TO_FIXP(30,4.6555282e-06F), TO_FIXP(30,4.9580707e-06F), 
	TO_FIXP(30,5.2802740e-06F), TO_FIXP(30,5.6234160e-06F),
	TO_FIXP(30,5.9888572e-06F), TO_FIXP(30,6.3780469e-06F), 
	TO_FIXP(30,6.7925283e-06F), TO_FIXP(30,7.2339451e-06F),
	TO_FIXP(30,7.7040476e-06F), TO_FIXP(30,8.2047000e-06F), 
	TO_FIXP(30,8.7378876e-06F), TO_FIXP(30,9.3057248e-06F),
	TO_FIXP(30,9.9104632e-06F), TO_FIXP(30,1.0554501e-05F), 
	TO_FIXP(30,1.1240392e-05F), TO_FIXP(30,1.1970856e-05F),
	TO_FIXP(30,1.2748789e-05F), TO_FIXP(30,1.3577278e-05F), 
	TO_FIXP(30,1.4459606e-05F), TO_FIXP(30,1.5399272e-05F),
	TO_FIXP(30,1.6400004e-05F), TO_FIXP(30,1.7465768e-05F), 
	TO_FIXP(30,1.8600792e-05F), TO_FIXP(30,1.9809576e-05F),
	TO_FIXP(30,2.1096914e-05F), TO_FIXP(30,2.2467911e-05F), 
	TO_FIXP(30,2.3928002e-05F), TO_FIXP(30,2.5482978e-05F),
	TO_FIXP(30,2.7139006e-05F), TO_FIXP(30,2.8902651e-05F), 
	TO_FIXP(30,3.0780908e-05F), TO_FIXP(30,3.2781225e-05F),
	TO_FIXP(30,3.4911534e-05F), TO_FIXP(30,3.7180282e-05F), 
	TO_FIXP(30,3.9596466e-05F), TO_FIXP(30,4.2169667e-05F),
	TO_FIXP(30,4.4910090e-05F), TO_FIXP(30,4.7828601e-05F), 
	TO_FIXP(30,5.0936773e-05F), TO_FIXP(30,5.4246931e-05F),
	TO_FIXP(30,5.7772202e-05F), TO_FIXP(30,6.1526565e-05F), 
	TO_FIXP(30,6.5524908e-05F), TO_FIXP(30,6.9783085e-05F),
	TO_FIXP(30,7.4317983e-05F), TO_FIXP(30,7.9147585e-05F), 
	TO_FIXP(30,8.4291040e-05F), TO_FIXP(30,8.9768747e-05F),
	TO_FIXP(30,9.5602426e-05F), TO_FIXP(30,0.00010181521F), 
	TO_FIXP(30,0.00010843174F), TO_FIXP(30,0.00011547824F),
	TO_FIXP(30,0.00012298267F), TO_FIXP(30,0.00013097477F), 
	TO_FIXP(30,0.00013948625F), TO_FIXP(30,0.00014855085F),
	TO_FIXP(30,0.00015820453F), TO_FIXP(30,0.00016848555F), 
	TO_FIXP(30,0.00017943469F), TO_FIXP(30,0.00019109536F),
	TO_FIXP(30,0.00020351382F), TO_FIXP(30,0.00021673929F), 
	TO_FIXP(30,0.00023082423F), TO_FIXP(30,0.00024582449F),
	TO_FIXP(30,0.00026179955F), TO_FIXP(30,0.00027881276F), 
	TO_FIXP(30,0.00029693158F), TO_FIXP(30,0.00031622787F),
	TO_FIXP(30,0.00033677814F), TO_FIXP(30,0.00035866388F), 
	TO_FIXP(30,0.00038197188F), TO_FIXP(30,0.00040679456F),
	TO_FIXP(30,0.00043323036F), TO_FIXP(30,0.00046138411F), 
	TO_FIXP(30,0.00049136745F), TO_FIXP(30,0.00052329927F),
	TO_FIXP(30,0.00055730621F), TO_FIXP(30,0.00059352311F), 
	TO_FIXP(30,0.00063209358F), TO_FIXP(30,0.00067317058F),
	TO_FIXP(30,0.00071691700F), TO_FIXP(30,0.00076350630F), 
	TO_FIXP(30,0.00081312324F), TO_FIXP(30,0.00086596457F),
	TO_FIXP(30,0.00092223983F), TO_FIXP(30,0.00098217216F), 
	TO_FIXP(30,0.0010459992F), TO_FIXP(30,0.0011139742F),
	TO_FIXP(30,0.0011863665F), TO_FIXP(30,0.0012634633F),
	TO_FIXP(30,0.0013455702F), TO_FIXP(30,0.0014330129F),
	TO_FIXP(30,0.0015261382F), TO_FIXP(30,0.0016253153F),
	TO_FIXP(30,0.0017309374F), TO_FIXP(30,0.0018434235F),
	TO_FIXP(30,0.0019632195F), TO_FIXP(30,0.0020908006F),
	TO_FIXP(30,0.0022266726F), TO_FIXP(30,0.0023713743F),
	TO_FIXP(30,0.0025254795F), TO_FIXP(30,0.0026895994F),
	TO_FIXP(30,0.0028643847F), TO_FIXP(30,0.0030505286F),
	TO_FIXP(30,0.0032487691F), TO_FIXP(30,0.0034598925F),
	TO_FIXP(30,0.0036847358F), TO_FIXP(30,0.0039241906F),
	TO_FIXP(30,0.0041792066F), TO_FIXP(30,0.0044507950F),
	TO_FIXP(30,0.0047400328F), TO_FIXP(30,0.0050480668F),
	TO_FIXP(30,0.0053761186F), TO_FIXP(30,0.0057254891F),
	TO_FIXP(30,0.0060975636F), TO_FIXP(30,0.0064938176F),
	TO_FIXP(30,0.0069158225F), TO_FIXP(30,0.0073652516F),
	TO_FIXP(30,0.0078438871F), TO_FIXP(30,0.0083536271F),
	TO_FIXP(30,0.0088964928F), TO_FIXP(30,0.009474637F),
	TO_FIXP(30,0.010090352F), TO_FIXP(30,0.010746080F),
	TO_FIXP(30,0.011444421F), TO_FIXP(30,0.012188144F),
	TO_FIXP(30,0.012980198F), TO_FIXP(30,0.013823725F),
	TO_FIXP(30,0.014722068F), TO_FIXP(30,0.015678791F),
	TO_FIXP(30,0.016697687F), TO_FIXP(30,0.017782797F),
	TO_FIXP(30,0.018938423F), TO_FIXP(30,0.020169149F),
	TO_FIXP(30,0.021479854F), TO_FIXP(30,0.022875735F),
	TO_FIXP(30,0.024362330F), TO_FIXP(30,0.025945531F),
	TO_FIXP(30,0.027631618F), TO_FIXP(30,0.029427276F),
	TO_FIXP(30,0.031339626F), TO_FIXP(30,0.033376252F),
	TO_FIXP(30,0.035545228F), TO_FIXP(30,0.037855157F),
	TO_FIXP(30,0.040315199F), TO_FIXP(30,0.042935108F),
	TO_FIXP(30,0.045725273F), TO_FIXP(30,0.048696758F),
	TO_FIXP(30,0.051861348F), TO_FIXP(30,0.055231591F),
	TO_FIXP(30,0.058820850F), TO_FIXP(30,0.062643361F),
	TO_FIXP(30,0.066714279F), TO_FIXP(30,0.071049749F),
	TO_FIXP(30,0.075666962F), TO_FIXP(30,0.080584227F),
	TO_FIXP(30,0.085821044F), TO_FIXP(30,0.091398179F),
	TO_FIXP(30,0.097337747F), TO_FIXP(30,0.10366330F),
	TO_FIXP(30,0.11039993F), TO_FIXP(30,0.11757434F), 
	TO_FIXP(30,0.12521498F), TO_FIXP(30,0.13335215F),
	TO_FIXP(30,0.14201813F), TO_FIXP(30,0.15124727F),
	TO_FIXP(30,0.16107617F), TO_FIXP(30,0.17154380F),
	TO_FIXP(30,0.18269168F), TO_FIXP(30,0.19456402F),
	TO_FIXP(30,0.20720788F), TO_FIXP(30,0.22067342F),
	TO_FIXP(30,0.23501402F), TO_FIXP(30,0.25028656F),
	TO_FIXP(30,0.26655159F), TO_FIXP(30,0.28387361F),
	TO_FIXP(30,0.30232132F), TO_FIXP(30,0.32196786F),
	TO_FIXP(30,0.34289114F), TO_FIXP(30,0.36517414F),
	TO_FIXP(30,0.38890521F), TO_FIXP(30,0.41417847F),
	TO_FIXP(30,0.44109412F), TO_FIXP(30,0.46975890F),
	TO_FIXP(30,0.50028648F), TO_FIXP(30,0.53279791F),
	TO_FIXP(30,0.56742212F), TO_FIXP(30,0.60429640F),
	TO_FIXP(30,0.64356699F), TO_FIXP(30,0.68538959F),
	TO_FIXP(30,0.72993007F), TO_FIXP(30,0.77736504F),
	TO_FIXP(30,0.82788260F), TO_FIXP(30,0.88168307F),
	TO_FIXP(30,0.9389798F), TO_FIXP(30,1.F),
};

static void render_line(int x0,int x1,int y0,int y1,FIXP *d){
  int dy=y1-y0;
  int adx=x1-x0;
  int ady=abs(dy);
  int base=dy/adx;
  int sy=(dy<0?base-1:base+1);
  int x=x0;
  int y=y0;
  int err=0;

  ady-=abs(base*adx);

  /*
   * FIXP note: d[] (x.16) * FLOOR_fromdB_LOOKUP[] (x.30) = (x.46).
   * We want to scale it back to FIXP_FRACBITS.
   */
  d[x]=MUL(46-FIXP_FRACBITS,d[x],FLOOR_fromdB_LOOKUP[y]);
  while(++x<x1){
    err=err+ady;
    if(err>=adx){
      err-=adx;
      y+=sy;
    }else{
      y+=base;
    }
    d[x]=MUL(46-FIXP_FRACBITS,d[x],FLOOR_fromdB_LOOKUP[y]);
  }
}

static void *floor1_inverse1(vorbis_block *vb,vorbis_look_floor *in){
  vorbis_look_floor1 *look=(vorbis_look_floor1 *)in;
  vorbis_info_floor1 *info=look->vi;
  codec_setup_info   *ci=vb->vd->vi->codec_setup;
  
  int i,j,k;
  codebook *books=ci->fullbooks;   

  /* unpack wrapped/predicted values from stream */
  if(oggpack_read(&vb->opb,1)==1){
    int *fit_value=_vorbis_block_alloc(vb,(look->posts)*sizeof(*fit_value));

    fit_value[0]=oggpack_read(&vb->opb,ilog(look->quant_q-1));
    fit_value[1]=oggpack_read(&vb->opb,ilog(look->quant_q-1));

    /* partition by partition */
    /* partition by partition */
    for(i=0,j=2;i<info->partitions;i++){
      int class=info->partitionclass[i];
      int cdim=info->class_dim[class];
      int csubbits=info->class_subs[class];
      int csub=1<<csubbits;
      int cval=0;

      /* decode the partition's first stage cascade value */
      if(csubbits){
	cval=vorbis_book_decode(books+info->class_book[class],&vb->opb);

	if(cval==-1)goto eop;
      }

      for(k=0;k<cdim;k++){
	int book=info->class_subbook[class][cval&(csub-1)];
	cval>>=csubbits;
	if(book>=0){
	  if((fit_value[j+k]=vorbis_book_decode(books+book,&vb->opb))==-1)
	    goto eop;
	}else{
	  fit_value[j+k]=0;
	}
      }
      j+=cdim;
    }

    /* unwrap positive values and reconsitute via linear interpolation */
    for(i=2;i<look->posts;i++){
      int predicted=render_point(info->postlist[look->loneighbor[i-2]],
				 info->postlist[look->hineighbor[i-2]],
				 fit_value[look->loneighbor[i-2]],
				 fit_value[look->hineighbor[i-2]],
				 info->postlist[i]);
      int hiroom=look->quant_q-predicted;
      int loroom=predicted;
      int room=(hiroom<loroom?hiroom:loroom)<<1;
      int val=fit_value[i];

      if(val){
	if(val>=room){
	  if(hiroom>loroom){
	    val = val-loroom;
	  }else{
	  val = -1-(val-hiroom);
	  }
	}else{
	  if(val&1){
	    val= -((val+1)>>1);
	  }else{
	    val>>=1;
	  }
	}

	fit_value[i]=val+predicted;
	fit_value[look->loneighbor[i-2]]&=0x7fff;
	fit_value[look->hineighbor[i-2]]&=0x7fff;

      }else{
	fit_value[i]=predicted|0x8000;
      }
	
    }

    return(fit_value);
  }
 eop:
  return(NULL);
}

static int floor1_inverse2(vorbis_block *vb,vorbis_look_floor *in,void *memo,
			  FIXP *out){
  vorbis_look_floor1 *look=(vorbis_look_floor1 *)in;
  vorbis_info_floor1 *info=look->vi;

  codec_setup_info   *ci=vb->vd->vi->codec_setup;
  int                  n=ci->blocksizes[vb->mode]/2;
  int j;

  if(memo){
    /* render the lines */
    int *fit_value=(int *)memo;
    int hx=0;
    int lx=0;
    int ly=fit_value[0]*info->mult;
    for(j=1;j<look->posts;j++){
      int current=look->forward_index[j];
      int hy=fit_value[current]&0x7fff;
      if(hy==fit_value[current]){
	
	hy*=info->mult;
	hx=info->postlist[current];
	
	render_line(lx,hx,ly,hy,out);
	
	lx=hx;
	ly=hy;
      }
    }
    for(j=hx;j<n;j++)out[j]*=ly; /* be certain */    
    return(1);
  }
  memset(out,0,sizeof(*out)*n);
  return(0);
}

/* export hooks */
vorbis_func_floor floor1_exportbundle={
  NULL,&floor1_unpack,&floor1_look,NULL,&floor1_free_info,
  &floor1_free_look,NULL,&floor1_inverse1,&floor1_inverse2
};