info.c

在x86平台上运行不可信任代码的sandbox。

    if(ci->map_type[i]<0 || ci->map_type[i]>=VI_MAPB)goto err_out;
    ci->map_param[i]=_mapping_P[ci->map_type[i]]->unpack(vi,opb);
    if(!ci->map_param[i])goto err_out;
  }
  
  /* mode settings */
  ci->modes=oggpack_read(opb,6)+1;
  /*vi->mode_param=_ogg_calloc(vi->modes,sizeof(void *));*/
  for(i=0;i<ci->modes;i++){
    ci->mode_param[i]=_ogg_calloc(1,sizeof(*ci->mode_param[i]));
    ci->mode_param[i]->blockflag=oggpack_read(opb,1);
    ci->mode_param[i]->windowtype=oggpack_read(opb,16);
    ci->mode_param[i]->transformtype=oggpack_read(opb,16);
    ci->mode_param[i]->mapping=oggpack_read(opb,8);

    if(ci->mode_param[i]->windowtype>=VI_WINDOWB)goto err_out;
    if(ci->mode_param[i]->transformtype>=VI_WINDOWB)goto err_out;
    if(ci->mode_param[i]->mapping>=ci->maps)goto err_out;
  }
  
  if(oggpack_read(opb,1)!=1)goto err_out; /* top level EOP check */

  return(0);
 err_out:
  vorbis_info_clear(vi);
  return(OV_EBADHEADER);
}

/* The Vorbis header is in three packets; the initial small packet in
   the first page that identifies basic parameters, a second packet
   with bitstream comments and a third packet that holds the
   codebook. */

int vorbis_synthesis_headerin(vorbis_info *vi,vorbis_comment *vc,ogg_packet *op){
  oggpack_buffer opb;
  
  if(op){
    oggpack_readinit(&opb,op->packet,op->bytes);

    /* Which of the three types of header is this? */
    /* Also verify header-ness, vorbis */
    {
      char buffer[6];
      int packtype=oggpack_read(&opb,8);
      memset(buffer,0,6);
      _v_readstring(&opb,buffer,6);
      if(memcmp(buffer,"vorbis",6)){
	/* not a vorbis header */
	return(OV_ENOTVORBIS);
      }
      switch(packtype){
      case 0x01: /* least significant *bit* is read first */
	if(!op->b_o_s){
	  /* Not the initial packet */
	  return(OV_EBADHEADER);
	}
	if(vi->rate!=0){
	  /* previously initialized info header */
	  return(OV_EBADHEADER);
	}

	return(_vorbis_unpack_info(vi,&opb));

      case 0x03: /* least significant *bit* is read first */
	if(vi->rate==0){
	  /* um... we didn't get the initial header */
	  return(OV_EBADHEADER);
	}

	return(_vorbis_unpack_comment(vc,&opb));

      case 0x05: /* least significant *bit* is read first */
	if(vi->rate==0 || vc->vendor==NULL){
	  /* um... we didn;t get the initial header or comments yet */
	  return(OV_EBADHEADER);
	}

	return(_vorbis_unpack_books(vi,&opb));

      default:
	/* Not a valid vorbis header type */
	return(OV_EBADHEADER);
	break;
      }
    }
  }
  return(OV_EBADHEADER);
}

/* pack side **********************************************************/

static int _vorbis_pack_info(oggpack_buffer *opb,vorbis_info *vi){
  codec_setup_info     *ci=vi->codec_setup;
  if(!ci)return(OV_EFAULT);

  /* preamble */  
  oggpack_write(opb,0x01,8);
  _v_writestring(opb,"vorbis", 6);

  /* basic information about the stream */
  oggpack_write(opb,0x00,32);
  oggpack_write(opb,vi->channels,8);
  oggpack_write(opb,vi->rate,32);

  oggpack_write(opb,vi->bitrate_upper,32);
  oggpack_write(opb,vi->bitrate_nominal,32);
  oggpack_write(opb,vi->bitrate_lower,32);

  oggpack_write(opb,ilog2(ci->blocksizes[0]),4);
  oggpack_write(opb,ilog2(ci->blocksizes[1]),4);
  oggpack_write(opb,1,1);

  return(0);
}

static int _vorbis_pack_comment(oggpack_buffer *opb,vorbis_comment *vc){
  char temp[]="Xiph.Org libVorbis I 20030909";
  int bytes = strlen(temp);

  /* preamble */  
  oggpack_write(opb,0x03,8);
  _v_writestring(opb,"vorbis", 6);

  /* vendor */
  oggpack_write(opb,bytes,32);
  _v_writestring(opb,temp, bytes);
  
  /* comments */

  oggpack_write(opb,vc->comments,32);
  if(vc->comments){
    int i;
    for(i=0;i<vc->comments;i++){
      if(vc->user_comments[i]){
	oggpack_write(opb,vc->comment_lengths[i],32);
	_v_writestring(opb,vc->user_comments[i], vc->comment_lengths[i]);
      }else{
	oggpack_write(opb,0,32);
      }
    }
  }
  oggpack_write(opb,1,1);

  return(0);
}
 
static int _vorbis_pack_books(oggpack_buffer *opb,vorbis_info *vi){
  codec_setup_info     *ci=vi->codec_setup;
  int i;
  if(!ci)return(OV_EFAULT);

  oggpack_write(opb,0x05,8);
  _v_writestring(opb,"vorbis", 6);

  /* books */
  oggpack_write(opb,ci->books-1,8);
  for(i=0;i<ci->books;i++)
    if(vorbis_staticbook_pack(ci->book_param[i],opb))goto err_out;

  /* times; hook placeholders */
  oggpack_write(opb,0,6);
  oggpack_write(opb,0,16);

  /* floors */
  oggpack_write(opb,ci->floors-1,6);
  for(i=0;i<ci->floors;i++){
    oggpack_write(opb,ci->floor_type[i],16);
    if(_floor_P[ci->floor_type[i]]->pack)
      _floor_P[ci->floor_type[i]]->pack(ci->floor_param[i],opb);
    else
      goto err_out;
  }

  /* residues */
  oggpack_write(opb,ci->residues-1,6);
  for(i=0;i<ci->residues;i++){
    oggpack_write(opb,ci->residue_type[i],16);
    _residue_P[ci->residue_type[i]]->pack(ci->residue_param[i],opb);
  }

  /* maps */
  oggpack_write(opb,ci->maps-1,6);
  for(i=0;i<ci->maps;i++){
    oggpack_write(opb,ci->map_type[i],16);
    _mapping_P[ci->map_type[i]]->pack(vi,ci->map_param[i],opb);
  }

  /* modes */
  oggpack_write(opb,ci->modes-1,6);
  for(i=0;i<ci->modes;i++){
    oggpack_write(opb,ci->mode_param[i]->blockflag,1);
    oggpack_write(opb,ci->mode_param[i]->windowtype,16);
    oggpack_write(opb,ci->mode_param[i]->transformtype,16);
    oggpack_write(opb,ci->mode_param[i]->mapping,8);
  }
  oggpack_write(opb,1,1);

  return(0);
err_out:
  return(-1);
} 

int vorbis_commentheader_out(vorbis_comment *vc,
    				      ogg_packet *op){

  oggpack_buffer opb;

  oggpack_writeinit(&opb);
  if(_vorbis_pack_comment(&opb,vc)) return OV_EIMPL;

  op->packet = _ogg_malloc(oggpack_bytes(&opb));
  memcpy(op->packet, opb.buffer, oggpack_bytes(&opb));

  op->bytes=oggpack_bytes(&opb);
  op->b_o_s=0;
  op->e_o_s=0;
  op->granulepos=0;

  return 0;
}

int vorbis_analysis_headerout(vorbis_dsp_state *v,
			      vorbis_comment *vc,
			      ogg_packet *op,
			      ogg_packet *op_comm,
			      ogg_packet *op_code){
  int ret=OV_EIMPL;
  vorbis_info *vi=v->vi;
  oggpack_buffer opb;
  private_state *b=v->backend_state;

  if(!b){
    ret=OV_EFAULT;
    goto err_out;
  }

  /* first header packet **********************************************/

  oggpack_writeinit(&opb);
  if(_vorbis_pack_info(&opb,vi))goto err_out;

  /* build the packet */
  if(b->header)_ogg_free(b->header);
  b->header=_ogg_malloc(oggpack_bytes(&opb));
  memcpy(b->header,opb.buffer,oggpack_bytes(&opb));
  op->packet=b->header;
  op->bytes=oggpack_bytes(&opb);
  op->b_o_s=1;
  op->e_o_s=0;
  op->granulepos=0;

  /* second header packet (comments) **********************************/

  oggpack_reset(&opb);
  if(_vorbis_pack_comment(&opb,vc))goto err_out;

  if(b->header1)_ogg_free(b->header1);
  b->header1=_ogg_malloc(oggpack_bytes(&opb));
  memcpy(b->header1,opb.buffer,oggpack_bytes(&opb));
  op_comm->packet=b->header1;
  op_comm->bytes=oggpack_bytes(&opb);
  op_comm->b_o_s=0;
  op_comm->e_o_s=0;
  op_comm->granulepos=0;

  /* third header packet (modes/codebooks) ****************************/

  oggpack_reset(&opb);
  if(_vorbis_pack_books(&opb,vi))goto err_out;

  if(b->header2)_ogg_free(b->header2);
  b->header2=_ogg_malloc(oggpack_bytes(&opb));
  memcpy(b->header2,opb.buffer,oggpack_bytes(&opb));
  op_code->packet=b->header2;
  op_code->bytes=oggpack_bytes(&opb);
  op_code->b_o_s=0;
  op_code->e_o_s=0;
  op_code->granulepos=0;

  oggpack_writeclear(&opb);
  return(0);
 err_out:
  oggpack_writeclear(&opb);
  memset(op,0,sizeof(*op));
  memset(op_comm,0,sizeof(*op_comm));
  memset(op_code,0,sizeof(*op_code));

  if(b->header)_ogg_free(b->header);
  if(b->header1)_ogg_free(b->header1);
  if(b->header2)_ogg_free(b->header2);
  b->header=NULL;
  b->header1=NULL;
  b->header2=NULL;
  return(ret);
}

double vorbis_granule_time(vorbis_dsp_state *v,ogg_int64_t granulepos){
  if(granulepos>=0)
    return((double)granulepos/v->vi->rate);
  return(-1);
}