public int read(long fileOffset,byte[] buffer,int offset,int length) throws IOException {
  _file.seek(fileOffset);
  return _file.read(buffer,offset,length);
}

public int read ( long fileOffset , byte [ ] buffer , int offset , int length ) throws IOException { _file . seek ( fileOffset ) ; return _file . read ( buffer , offset , length ) ; }
reads a block from a given location .
