streamstate.java

来自「java ogg player library. for play back o」· Java 代码 · 共 658 行 · 第 1/2 页

	  lacing_vals[lacing_fill]|=0x100;
	  bos=0;
	}
      
	if(val<255)saved=lacing_fill;
      
	lacing_fill++;
	segptr++;
      
	if(val<255)lacing_packet=lacing_fill;
      }
  
    /* set the granulepos on the last pcmval of the last full packet */
      if(saved!=-1){
	granule_vals[saved]=granulepos;
      }
    }

    if(eos!=0){
      e_o_s=1;
      if(lacing_fill>0)
	lacing_vals[lacing_fill-1]|=0x200;
    }

    pageno=_pageno+1;
    return(0);
  }


/* This will flush remaining packets into a page (returning nonzero),
   even if there is not enough data to trigger a flush normally
   (undersized page). If there are no packets or partial packets to
   flush, ogg_stream_flush returns 0.  Note that ogg_stream_flush will
   try to flush a normal sized page like ogg_stream_pageout; a call to
   ogg_stream_flush does not gurantee that all packets have flushed.
   Only a return value of 0 from ogg_stream_flush indicates all packet
   data is flushed into pages.

   ogg_stream_page will flush the last page in a stream even if it's
   undersized; you almost certainly want to use ogg_stream_pageout
   (and *not* ogg_stream_flush) unless you need to flush an undersized
   page in the middle of a stream for some reason. */

  public int flush(Page og){

//System.out.println(this+" ---body_returned: "+body_returned);

    int i;
    int vals=0;
    int maxvals=(lacing_fill>255?255:lacing_fill);
    int bytes=0;
    int acc=0;
    long granule_pos=granule_vals[0];

    if(maxvals==0)return(0);
  
    /* construct a page */
    /* decide how many segments to include */
  
    /* If this is the initial header case, the first page must only include
       the initial header packet */
    if(b_o_s==0){  /* 'initial header page' case */
      granule_pos=0;
      for(vals=0;vals<maxvals;vals++){
        if((lacing_vals[vals]&0x0ff)<255){
	  vals++;
	  break;
        }
      }
    }
    else{
      for(vals=0;vals<maxvals;vals++){
        if(acc>4096)break;
        acc+=(lacing_vals[vals]&0x0ff);
        granule_pos=granule_vals[vals];
      }
    }

    /* construct the header in temp storage */
    System.arraycopy("OggS".getBytes(), 0, header, 0, 4);
  
    /* stream structure version */
    header[4]=0x00;

    /* continued packet flag? */
    header[5]=0x00;
    if((lacing_vals[0]&0x100)==0)header[5]|=0x01;
    /* first page flag? */
    if(b_o_s==0) header[5]|=0x02;
    /* last page flag? */
    if(e_o_s!=0 && lacing_fill==vals) header[5]|=0x04;
    b_o_s=1;

    /* 64 bits of PCM position */
    for(i=6;i<14;i++){
      header[i]=(byte)granule_pos;
      granule_pos>>>=8;
    }

    /* 32 bits of stream serial number */
    {
      int _serialno=serialno;
      for(i=14;i<18;i++){
        header[i]=(byte)_serialno;
        _serialno>>>=8;
      }
    }

    /* 32 bits of page counter (we have both counter and page header
       because this val can roll over) */
    if(pageno==-1)pageno=0;       /* because someone called
				     stream_reset; this would be a
				     strange thing to do in an
				     encode stream, but it has
				     plausible uses */
    {
      int _pageno=pageno++;
      for(i=18;i<22;i++){
        header[i]=(byte)_pageno;
        _pageno>>>=8;
      }
    }
  
    /* zero for computation; filled in later */
    header[22]=0;
    header[23]=0;
    header[24]=0;
    header[25]=0;
  
    /* segment table */
    header[26]=(byte)vals;
    for(i=0;i<vals;i++){
      header[i+27]=(byte)lacing_vals[i];
      bytes+=(header[i+27]&0xff);
    }
  
    /* set pointers in the ogg_page struct */
    og.header_base=header;
    og.header=0;
    og.header_len=header_fill=vals+27;
    og.body_base=body_data;
    og.body=body_returned;
    og.body_len=bytes;

    /* advance the lacing data and set the body_returned pointer */
  
//System.out.println("###body_returned: "+body_returned);

    lacing_fill-=vals;
    System.arraycopy(lacing_vals, vals, lacing_vals, 0, lacing_fill*4);
    System.arraycopy(granule_vals, vals, granule_vals, 0, lacing_fill*8);
    body_returned+=bytes;

//System.out.println("####body_returned: "+body_returned);
  
    /* calculate the checksum */
  
    og.checksum();

    /* done */
    return(1);
  }


/* This constructs pages from buffered packet segments.  The pointers
returned are to static buffers; do not free. The returned buffers are
good only until the next call (using the same ogg_stream_state) */
  public int pageout(Page og){
//    if(body_returned!=0){
//    /* advance packet data according to the body_returned pointer. We
//       had to keep it around to return a pointer into the buffer last
//       call */
//
//      body_fill-=body_returned;
//      if(body_fill!=0){ // overlap?
//	System.arraycopy(body_data, body_returned, body_data, 0, body_fill);
//      }
//      body_returned=0;
//    }
//
//System.out.println("pageout: e_o_s="+e_o_s+" lacing_fill="+lacing_fill+" body_fill="+body_fill+", lacing_fill="+lacing_fill+" b_o_s="+b_o_s);
//
//    if((e_o_s!=0&&lacing_fill!=0) ||  /* 'were done, now flush' case */
//       body_fill > 4096 ||          /* 'page nominal size' case */
//       lacing_fill>=255 ||          /* 'segment table full' case */
//       (lacing_fill!=0&&b_o_s==0)){  /* 'initial header page' case */
//      int vals=0,bytes=0;
//      int maxvals=(lacing_fill>255?255:lacing_fill);
//      long acc=0;
//      long pcm_pos=granule_vals[0];
//
//    /* construct a page */
//    /* decide how many segments to include */
//
//    /* If this is the initial header case, the first page must only include
//       the initial header packet */
//      if(b_o_s==0){  /* 'initial header page' case */
//        pcm_pos=0;
//        for(vals=0;vals<maxvals;vals++){
//  	  if((lacing_vals[vals]&0x0ff)<255){
// 	    vals++;
//	    break;
//	  }
//        }
//      }
//      else{
//        for(vals=0;vals<maxvals;vals++){
//	  if(acc>4096)break;
//	  acc+=lacing_vals[vals]&0x0ff;
//	  pcm_pos=granule_vals[vals];
//        }
//      }
//
//    /* construct the header in temp storage */
//      System.arraycopy("OggS".getBytes(), 0, header, 0, 4);
//
//    /* stream structure version */
//      header[4]=0x00;
//    
//    /* continued packet flag? */
//      header[5]=0x00;
//      if((lacing_vals[0]&0x100)==0)header[5]|=0x01;
//    /* first page flag? */
//      if(b_o_s==0)header[5]|=0x02;
//    /* last page flag? */
//      if(e_o_s!=0 && lacing_fill==vals)header[5]|=0x04;
//      b_o_s=1;
//
//    /* 64 bits of PCM position */
//      for(int i=6;i<14;i++){
//        header[i]=(byte)pcm_pos;
//        pcm_pos>>>=8;
//      }
//
//    /* 32 bits of stream serial number */
//      {
//        int serialn=serialno;
//        for(int i=14;i<18;i++){
//  	  header[i]=(byte)serialn;
//	  serialn>>>=8;
//        }
//      }
//
//
///* 32 bits of page counter (we have both counter and page header
//       because this val can roll over) */
//      if(pageno==-1)pageno=0; /* because someone called
//                                       stream_reset; this would be a
//                                       strange thing to do in an
//                                       encode stream, but it has
//                                       plausible uses */
//      {
//        int pagen=pageno++;
//        for(int i=18;i<22;i++){
//	  header[i]=(byte)pagen;
//	  pagen>>>=8;
//        }
//      }
//
//    /* zero for computation; filled in later */
//      header[22]=0;
//      header[23]=0;
//      header[24]=0;
//      header[25]=0;
//
//    /* segment table */
//      header[26]=(byte)vals;
//      for(int i=0;i<vals;i++){
//        header[i+27]=(byte)lacing_vals[i];
//        bytes+=header[i+27]&0xff;
////      bytes+=header[i+27]=(lacing_vals[i]&0xff);
//      }
//      
//    /* advance the lacing data and set the body_returned pointer */
//
//      lacing_fill-=vals;
//      System.arraycopy(lacing_vals, vals, lacing_vals, 0, lacing_fill);
//      System.arraycopy(granule_vals, vals, granule_vals, 0, lacing_fill);
//      body_returned=bytes;
//
//    /* set pointers in the ogg_page struct */
//      og.header_base=header;
//      og.header=0;
//      og.header_len=header_fill=vals+27;
//
//      og.body_base=body_data;
//      og.body=0;
//      og.body_len=bytes;
//
//    /* calculate the checksum */
//
//      og.checksum();
//      return(1);
//    }
//    /* not enough data to construct a page and not end of stream */
//    return(0);
//System.out.println("pageout: "+body_returned);
    if((e_o_s!=0&&lacing_fill!=0) ||  /* 'were done, now flush' case */
        body_fill-body_returned> 4096 ||     /* 'page nominal size' case */
        lacing_fill>=255 ||          /* 'segment table full' case */
        (lacing_fill!=0&&b_o_s==0)){  /* 'initial header page' case */
      return flush(og);
    }
    return 0;
  }

  public int eof(){
    return e_o_s;
  }

  public int reset(){
    body_fill=0;
    body_returned=0;

    lacing_fill=0;
    lacing_packet=0;
    lacing_returned=0;

    header_fill=0;

    e_o_s=0;
    b_o_s=0;
    pageno=-1;
    packetno=0;
    granulepos=0;
    return(0);
  }
}