private static function _getPartialFileContent($file, $range)
    {
        $length = $range[1]-$range[0]+1;

        if( !$handle = fopen($file, 'r') )
            throw new Kwf_Exception(sprintf("Could not get handle for file %s", $file));
        if( fseek($handle, $range[0], SEEK_SET) == -1 )
            throw new Kwf_Exception(sprintf("Could not seek to byte offset {$rage[0]}"));

        $ret = fread($handle, $length);
        return $ret;
    }