function ip_csv2dat($input_file, $output_file) {

        $lines = file($input_file);
        $fh = fopen($output_file, 'wb+');
        fwrite($fh, 'TKdb');
        fwrite($fh, pack('l', 0));
        $min = NULL;
        $countries = array();
        $cnt = 0;
        $topidx = array();
        $minip = 0;
        $maxip = 0;
        foreach ($lines as $line) {
            $cnt++;
            $line = str_replace('"', '', $line);
            list($start, $end, $two, , ) = explode(',', $line, 4);
            $start = "$start" + 0;
            $end = "$end" + 0;
            if (!in_array($two, $countries)) {
                $countries[] = $two;
            }
            $countryidx = array_search($two, $countries);
            fwrite($fh, pack('VVv', $start, $end, $countryidx));
            list($aclassStart, , , ) = explode('.', long2ip($start));
            list($aclassEnd, , , ) = explode('.', long2ip($end));
            for ($i = $aclassStart; $i <= $aclassEnd; $i++) {
                if (!isset($topidx[$i])) {
                    $topidx[$i] = $cnt;
                }
            }
            if (is_null($min)) {
                $min = $start;
                $minip = $aclassStart;
            }
            $max = $end;
            $maxip = $aclassEnd;
        }
        $idx = ftell($fh);
        fwrite($fh, pack('VVVCv', $cnt, $min, $max, strlen(pack('VVv', 'P', 'H', 'P')), count($countries)));
        foreach ($countries as $country) {
            fwrite($fh, $country);
        }
        fwrite($fh, pack('CC', $minip, $maxip));
        $lastpos = 0;
        $pos = 0;
        for ($i = $minip; $i <= $maxip; $i++) {
            if (isset($topidx[$i])) {
                $pos = $topidx[$i];
                $lastpos = $pos;
            } else {
                $pos = -$lastpos;
            }
            fwrite($fh, pack('i', $pos));
        }
        fseek($fh, 4);
        fwrite($fh, pack('l', $idx));
        fclose($fh);
        return array(0 => $cnt, 1 => count($countries));

    }