private final static byte[] readBytes(RandomAccessFile f,long offs,int len) throws IOException {
  byte[] ret=new byte[len];
  f.seek(offs);
  f.readFully(ret);
  return ret;
}

private final static byte [ ] readBytes ( RandomAccessFile f , long offs , int len ) throws IOException { byte [ ] ret = new byte [ len ] ; f . seek ( offs ) ; f . readFully ( ret ) ; return ret ; }
read len bytes from offs in file f .
