floor1.c

在x86平台上运行不可信任代码的sandbox。

/********************************************************************
 *                                                                  *
 * 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 1994-2002             *
 * by the XIPHOPHORUS Company http://www.xiph.org/                  *
 *                                                                  *
 ********************************************************************

 function: floor backend 1 implementation
 last mod: $Id: floor1.c 1919 2005-07-24 14:18:04Z baford $

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

#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <ogg/ogg.h>
#include "vorbis/codec.h"
#include "codec_internal.h"
#include "registry.h"
#include "codebook.h"
#include "misc.h"
#include "scales.h"

#include <stdio.h>

#define floor1_rangedB 140 /* floor 1 fixed at -140dB to 0dB range */

typedef struct {
  int sorted_index[VIF_POSIT+2];
  int forward_index[VIF_POSIT+2];
  int reverse_index[VIF_POSIT+2];
  
  int hineighbor[VIF_POSIT];
  int loneighbor[VIF_POSIT];
  int posts;

  int n;
  int quant_q;
  vorbis_info_floor1 *vi;

  long phrasebits;
  long postbits;
  long frames;
} vorbis_look_floor1;

typedef struct lsfit_acc{
  long x0;
  long x1;

  long xa;
  long ya;
  long x2a;
  long y2a;
  long xya; 
  long an;
} lsfit_acc;

/***********************************************/
 
static void floor1_free_info(vorbis_info_floor *i){
  vorbis_info_floor1 *info=(vorbis_info_floor1 *)i;
  if(info){
    memset(info,0,sizeof(*info));
    _ogg_free(info);
  }
}

static void floor1_free_look(vorbis_look_floor *i){
  vorbis_look_floor1 *look=(vorbis_look_floor1 *)i;
  if(look){
    /*fprintf(stderr,"floor 1 bit usage %f:%f (%f total)\n",
	    (float)look->phrasebits/look->frames,
	    (float)look->postbits/look->frames,
	    (float)(look->postbits+look->phrasebits)/look->frames);*/

    memset(look,0,sizeof(*look));
    _ogg_free(look);
  }
}

static int ilog(unsigned int v){
  int ret=0;
  while(v){
    ret++;
    v>>=1;
  }
  return(ret);
}

static int ilog2(unsigned int v){
  int ret=0;
  if(v)--v;
  while(v){
    ret++;
    v>>=1;
  }
  return(ret);
}

static void floor1_pack (vorbis_info_floor *i,oggpack_buffer *opb){
  vorbis_info_floor1 *info=(vorbis_info_floor1 *)i;
  int j,k;
  int count=0;
  int rangebits;
  int maxposit=info->postlist[1];
  int maxclass=-1;

  /* save out partitions */
  oggpack_write(opb,info->partitions,5); /* only 0 to 31 legal */
  for(j=0;j<info->partitions;j++){
    oggpack_write(opb,info->partitionclass[j],4); /* only 0 to 15 legal */
    if(maxclass<info->partitionclass[j])maxclass=info->partitionclass[j];
  }

  /* save out partition classes */
  for(j=0;j<maxclass+1;j++){
    oggpack_write(opb,info->class_dim[j]-1,3); /* 1 to 8 */
    oggpack_write(opb,info->class_subs[j],2); /* 0 to 3 */
    if(info->class_subs[j])oggpack_write(opb,info->class_book[j],8);
    for(k=0;k<(1<<info->class_subs[j]);k++)
      oggpack_write(opb,info->class_subbook[j][k]+1,8);
  }

  /* save out the post list */
  oggpack_write(opb,info->mult-1,2);     /* only 1,2,3,4 legal now */ 
  oggpack_write(opb,ilog2(maxposit),4);
  rangebits=ilog2(maxposit);

  for(j=0,k=0;j<info->partitions;j++){
    count+=info->class_dim[info->partitionclass[j]]; 
    for(;k<count;k++)
      oggpack_write(opb,info->postlist[k+2],rangebits);
  }
}


static vorbis_info_floor *floor1_unpack (vorbis_info *vi,oggpack_buffer *opb){
  codec_setup_info     *ci=vi->codec_setup;
  int j,k,count=0,maxclass=-1,rangebits;

  vorbis_info_floor1 *info=_ogg_calloc(1,sizeof(*info));
  /* read partitions */
  info->partitions=oggpack_read(opb,5); /* only 0 to 31 legal */
  for(j=0;j<info->partitions;j++){
    info->partitionclass[j]=oggpack_read(opb,4); /* only 0 to 15 legal */
    if(maxclass<info->partitionclass[j])maxclass=info->partitionclass[j];
  }

  /* read partition classes */
  for(j=0;j<maxclass+1;j++){
    info->class_dim[j]=oggpack_read(opb,3)+1; /* 1 to 8 */
    info->class_subs[j]=oggpack_read(opb,2); /* 0,1,2,3 bits */
    if(info->class_subs[j]<0)
      goto err_out;
    if(info->class_subs[j])info->class_book[j]=oggpack_read(opb,8);
    if(info->class_book[j]<0 || info->class_book[j]>=ci->books)
      goto err_out;
    for(k=0;k<(1<<info->class_subs[j]);k++){
      info->class_subbook[j][k]=oggpack_read(opb,8)-1;
      if(info->class_subbook[j][k]<-1 || info->class_subbook[j][k]>=ci->books)
	goto err_out;
    }
  }

  /* read the post list */
  info->mult=oggpack_read(opb,2)+1;     /* only 1,2,3,4 legal now */ 
  rangebits=oggpack_read(opb,4);

  for(j=0,k=0;j<info->partitions;j++){
    count+=info->class_dim[info->partitionclass[j]]; 
    for(;k<count;k++){
      int t=info->postlist[k+2]=oggpack_read(opb,rangebits);
      if(t<0 || t>=(1<<rangebits))
	goto err_out;
    }
  }
  info->postlist[0]=0;
  info->postlist[1]=1<<rangebits;

  return(info);
  
 err_out:
  floor1_free_info(info);
  return(NULL);
}

static int icomp(const void *a,const void *b){
  return(**(int **)a-**(int **)b);
}

static vorbis_look_floor *floor1_look(vorbis_dsp_state *vd,
				      vorbis_info_floor *in){

  int *sortpointer[VIF_POSIT+2];
  vorbis_info_floor1 *info=(vorbis_info_floor1 *)in;
  vorbis_look_floor1 *look=_ogg_calloc(1,sizeof(*look));
  int i,j,n=0;

  look->vi=info;
  look->n=info->postlist[1];
 
  /* we drop each position value in-between already decoded values,
     and use linear interpolation to predict each new value past the
     edges.  The positions are read in the order of the position
     list... we precompute the bounding positions in the lookup.  Of
     course, the neighbors can change (if a position is declined), but
     this is an initial mapping */

  for(i=0;i<info->partitions;i++)n+=info->class_dim[info->partitionclass[i]];
  n+=2;
  look->posts=n;

  /* also store a sorted position index */
  for(i=0;i<n;i++)sortpointer[i]=info->postlist+i;
  qsort(sortpointer,n,sizeof(*sortpointer),icomp);

  /* points from sort order back to range number */
  for(i=0;i<n;i++)look->forward_index[i]=sortpointer[i]-info->postlist;
  /* points from range order to sorted position */
  for(i=0;i<n;i++)look->reverse_index[look->forward_index[i]]=i;
  /* we actually need the post values too */
  for(i=0;i<n;i++)look->sorted_index[i]=info->postlist[look->forward_index[i]];
  
  /* quantize values to multiplier spec */
  switch(info->mult){
  case 1: /* 1024 -> 256 */
    look->quant_q=256;
    break;
  case 2: /* 1024 -> 128 */
    look->quant_q=128;
    break;
  case 3: /* 1024 -> 86 */
    look->quant_q=86;
    break;
  case 4: /* 1024 -> 64 */
    look->quant_q=64;
    break;
  }

  /* discover our neighbors for decode where we don't use fit flags
     (that would push the neighbors outward) */
  for(i=0;i<n-2;i++){
    int lo=0;
    int hi=1;
    int lx=0;
    int hx=look->n;
    int currentx=info->postlist[i+2];
    for(j=0;j<i+2;j++){
      int x=info->postlist[j];
      if(x>lx && x<currentx){
	lo=j;
	lx=x;
      }
      if(x<hx && x>currentx){
	hi=j;
	hx=x;
      }
    }
    look->loneighbor[i]=lo;
    look->hineighbor[i]=hi;
  }

  return(look);
}

static int render_point(int x0,int x1,int y0,int y1,int x){
  y0&=0x7fff; /* mask off flag */
  y1&=0x7fff;
    
  {
    int dy=y1-y0;
    int adx=x1-x0;
    int ady=abs(dy);
    int err=ady*(x-x0);
    
    int off=err/adx;
    if(dy<0)return(y0-off);
    return(y0+off);
  }
}

static int vorbis_dBquant(const float *x){
  int i= *x*7.3142857f+1023.5f;
  if(i>1023)return(1023);
  if(i<0)return(0);
  return i;
}

static float FLOOR1_fromdB_LOOKUP[256]={
  1.0649863e-07F, 1.1341951e-07F, 1.2079015e-07F, 1.2863978e-07F, 
  1.3699951e-07F, 1.4590251e-07F, 1.5538408e-07F, 1.6548181e-07F, 
  1.7623575e-07F, 1.8768855e-07F, 1.9988561e-07F, 2.128753e-07F, 
  2.2670913e-07F, 2.4144197e-07F, 2.5713223e-07F, 2.7384213e-07F, 
  2.9163793e-07F, 3.1059021e-07F, 3.3077411e-07F, 3.5226968e-07F, 
  3.7516214e-07F, 3.9954229e-07F, 4.2550680e-07F, 4.5315863e-07F, 
  4.8260743e-07F, 5.1396998e-07F, 5.4737065e-07F, 5.8294187e-07F, 
  6.2082472e-07F, 6.6116941e-07F, 7.0413592e-07F, 7.4989464e-07F, 
  7.9862701e-07F, 8.5052630e-07F, 9.0579828e-07F, 9.6466216e-07F, 
  1.0273513e-06F, 1.0941144e-06F, 1.1652161e-06F, 1.2409384e-06F, 
  1.3215816e-06F, 1.4074654e-06F, 1.4989305e-06F, 1.5963394e-06F, 
  1.7000785e-06F, 1.8105592e-06F, 1.9282195e-06F, 2.0535261e-06F, 
  2.1869758e-06F, 2.3290978e-06F, 2.4804557e-06F, 2.6416497e-06F, 
  2.8133190e-06F, 2.9961443e-06F, 3.1908506e-06F, 3.3982101e-06F, 
  3.6190449e-06F, 3.8542308e-06F, 4.1047004e-06F, 4.3714470e-06F, 
  4.6555282e-06F, 4.9580707e-06F, 5.2802740e-06F, 5.6234160e-06F, 
  5.9888572e-06F, 6.3780469e-06F, 6.7925283e-06F, 7.2339451e-06F, 
  7.7040476e-06F, 8.2047000e-06F, 8.7378876e-06F, 9.3057248e-06F, 
  9.9104632e-06F, 1.0554501e-05F, 1.1240392e-05F, 1.1970856e-05F, 
  1.2748789e-05F, 1.3577278e-05F, 1.4459606e-05F, 1.5399272e-05F, 
  1.6400004e-05F, 1.7465768e-05F, 1.8600792e-05F, 1.9809576e-05F, 
  2.1096914e-05F, 2.2467911e-05F, 2.3928002e-05F, 2.5482978e-05F, 
  2.7139006e-05F, 2.8902651e-05F, 3.0780908e-05F, 3.2781225e-05F, 
  3.4911534e-05F, 3.7180282e-05F, 3.9596466e-05F, 4.2169667e-05F, 
  4.4910090e-05F, 4.7828601e-05F, 5.0936773e-05F, 5.4246931e-05F, 
  5.7772202e-05F, 6.1526565e-05F, 6.5524908e-05F, 6.9783085e-05F, 
  7.4317983e-05F, 7.9147585e-05F, 8.4291040e-05F, 8.9768747e-05F, 
  9.5602426e-05F, 0.00010181521F, 0.00010843174F, 0.00011547824F, 
  0.00012298267F, 0.00013097477F, 0.00013948625F, 0.00014855085F, 
  0.00015820453F, 0.00016848555F, 0.00017943469F, 0.00019109536F, 
  0.00020351382F, 0.00021673929F, 0.00023082423F, 0.00024582449F, 
  0.00026179955F, 0.00027881276F, 0.00029693158F, 0.00031622787F, 
  0.00033677814F, 0.00035866388F, 0.00038197188F, 0.00040679456F, 
  0.00043323036F, 0.00046138411F, 0.00049136745F, 0.00052329927F, 
  0.00055730621F, 0.00059352311F, 0.00063209358F, 0.00067317058F, 
  0.00071691700F, 0.00076350630F, 0.00081312324F, 0.00086596457F, 
  0.00092223983F, 0.00098217216F, 0.0010459992F, 0.0011139742F, 
  0.0011863665F, 0.0012634633F, 0.0013455702F, 0.0014330129F, 
  0.0015261382F, 0.0016253153F, 0.0017309374F, 0.0018434235F, 
  0.0019632195F, 0.0020908006F, 0.0022266726F, 0.0023713743F, 
  0.0025254795F, 0.0026895994F, 0.0028643847F, 0.0030505286F, 
  0.0032487691F, 0.0034598925F, 0.0036847358F, 0.0039241906F, 
  0.0041792066F, 0.0044507950F, 0.0047400328F, 0.0050480668F, 
  0.0053761186F, 0.0057254891F, 0.0060975636F, 0.0064938176F, 
  0.0069158225F, 0.0073652516F, 0.0078438871F, 0.0083536271F, 
  0.0088964928F, 0.009474637F, 0.010090352F, 0.010746080F, 
  0.011444421F, 0.012188144F, 0.012980198F, 0.013823725F, 
  0.014722068F, 0.015678791F, 0.016697687F, 0.017782797F, 
  0.018938423F, 0.020169149F, 0.021479854F, 0.022875735F, 
  0.024362330F, 0.025945531F, 0.027631618F, 0.029427276F, 
  0.031339626F, 0.033376252F, 0.035545228F, 0.037855157F, 
  0.040315199F, 0.042935108F, 0.045725273F, 0.048696758F, 
  0.051861348F, 0.055231591F, 0.058820850F, 0.062643361F, 
  0.066714279F, 0.071049749F, 0.075666962F, 0.080584227F, 
  0.085821044F, 0.091398179F, 0.097337747F, 0.10366330F, 
  0.11039993F, 0.11757434F, 0.12521498F, 0.13335215F, 
  0.14201813F, 0.15124727F, 0.16107617F, 0.17154380F, 
  0.18269168F, 0.19456402F, 0.20720788F, 0.22067342F, 
  0.23501402F, 0.25028656F, 0.26655159F, 0.28387361F, 
  0.30232132F, 0.32196786F, 0.34289114F, 0.36517414F, 
  0.38890521F, 0.41417847F, 0.44109412F, 0.46975890F, 
  0.50028648F, 0.53279791F, 0.56742212F, 0.60429640F, 
  0.64356699F, 0.68538959F, 0.72993007F, 0.77736504F, 
  0.82788260F, 0.88168307F, 0.9389798F, 1.F, 
};

static void render_line(int x0,int x1,int y0,int y1,float *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);

  d[x]*=FLOOR1_fromdB_LOOKUP[y];
  while(++x<x1){
    err=err+ady;
    if(err>=adx){
      err-=adx;
      y+=sy;
    }else{
      y+=base;
    }
    d[x]*=FLOOR1_fromdB_LOOKUP[y];
  }
}

static void render_line0(int x0,int x1,int y0,int y1,int *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);

  d[x]=y;
  while(++x<x1){
    err=err+ady;
    if(err>=adx){
      err-=adx;
      y+=sy;
    }else{
      y+=base;
    }
    d[x]=y;
  }
}

/* the floor has already been filtered to only include relevant sections */
static int accumulate_fit(const float *flr,const float *mdct,
			  int x0, int x1,lsfit_acc *a,
			  int n,vorbis_info_floor1 *info){
  long i;
  int quantized=vorbis_dBquant(flr+x0);

  long xa=0,ya=0,x2a=0,y2a=0,xya=0,na=0, xb=0,yb=0,x2b=0,y2b=0,xyb=0,nb=0;

  memset(a,0,sizeof(*a));
  a->x0=x0;
  a->x1=x1;
  if(x1>=n)x1=n-1;

  for(i=x0;i<=x1;i++){
    int quantized=vorbis_dBquant(flr+i);
    if(quantized){
      if(mdct[i]+info->twofitatten>=flr[i]){
	xa  += i;
	ya  += quantized;
	x2a += i*i;
	y2a += quantized*quantized;
	xya += i*quantized;
	na++;
      }else{
	xb  += i;
	yb  += quantized;
	x2b += i*i;
	y2b += quantized*quantized;
	xyb += i*quantized;
	nb++;
      }
    }
  }

  xb+=xa;
  yb+=ya;
  x2b+=x2a;
  y2b+=y2a;
  xyb+=xya;
  nb+=na;

  /* weight toward the actually used frequencies if we meet the threshhold */
  {
    int weight=nb*info->twofitweight/(na+1);

    a->xa=xa*weight+xb;
    a->ya=ya*weight+yb;
    a->x2a=x2a*weight+x2b;
    a->y2a=y2a*weight+y2b;
    a->xya=xya*weight+xyb;
    a->an=na*weight+nb;
  }

  return(na);
}

static void fit_line(lsfit_acc *a,int fits,int *y0,int *y1){
  long x=0,y=0,x2=0,y2=0,xy=0,an=0,i;
  long x0=a[0].x0;
  long x1=a[fits-1].x1;

  for(i=0;i<fits;i++){
    x+=a[i].xa;
    y+=a[i].ya;
    x2+=a[i].x2a;
    y2+=a[i].y2a;
    xy+=a[i].xya;
    an+=a[i].an;
  }

  if(*y0>=0){
    x+=   x0;
    y+=  *y0;
    x2+=  x0 *  x0;
    y2+= *y0 * *y0;
    xy+= *y0 *  x0;
    an++;
  }

  if(*y1>=0){
    x+=   x1;
    y+=  *y1;
    x2+=  x1 *  x1;
    y2+= *y1 * *y1;
    xy+= *y1 *  x1;
    an++;
  }
  
  if(an){
    /* need 64 bit multiplies, which C doesn't give portably as int */
    double fx=x;
    double fy=y;
    double fx2=x2;
    double fxy=xy;
    double denom=1./(an*fx2-fx*fx);
    double a=(fy*fx2-fxy*fx)*denom;
    double b=(an*fxy-fx*fy)*denom;
    *y0=rint(a+b*x0);
    *y1=rint(a+b*x1);
    
    /* limit to our range! */
    if(*y0>1023)*y0=1023;
    if(*y1>1023)*y1=1023;
    if(*y0<0)*y0=0;
    if(*y1<0)*y1=0;
    
  }else{
    *y0=0;
    *y1=0;
  }
}

/*static void fit_line_point(lsfit_acc *a,int fits,int *y0,int *y1){
  long y=0;
  int i;

  for(i=0;i<fits && y==0;i++)
    y+=a[i].ya;
  
  *y0=*y1=y;
  }*/

static int inspect_error(int x0,int x1,int y0,int y1,const float *mask,
			 const float *mdct,
			 vorbis_info_floor1 *info){
  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;
  int val=vorbis_dBquant(mask+x);