SimplePie_Parse_Date::date_w3cdtf PHP 메소드

    public function date_w3cdtf($date)
    {
        static $pcre;
        if (!$pcre) {
            $year = '([0-9]{4})';
            $month = $day = $hour = $minute = $second = '([0-9]{2})';
            $decimal = '([0-9]*)';
            $zone = '(?:(Z)|([+\\-])([0-9]{1,2}):?([0-9]{1,2}))';
            $pcre = '/^' . $year . '(?:-?' . $month . '(?:-?' . $day . '(?:[Tt\\x09\\x20]+' . $hour . '(?::?' . $minute . '(?::?' . $second . '(?:.' . $decimal . ')?)?)?' . $zone . ')?)?)?$/';
        }
        if (preg_match($pcre, $date, $match)) {
            /*
            Capturing subpatterns:
            1: Year
            2: Month
            3: Day
            4: Hour
            5: Minute
            6: Second
            7: Decimal fraction of a second
            8: Zulu
            9: Timezone ±
            10: Timezone hours
            11: Timezone minutes
            */
            // Fill in empty matches
            for ($i = count($match); $i <= 3; $i++) {
                $match[$i] = '1';
            }
            for ($i = count($match); $i <= 7; $i++) {
                $match[$i] = '0';
            }
            // Numeric timezone
            if (isset($match[9]) && $match[9] !== '') {
                $timezone = $match[10] * 3600;
                $timezone += $match[11] * 60;
                if ($match[9] === '-') {
                    $timezone = 0 - $timezone;
                }
            } else {
                $timezone = 0;
            }
            // Convert the number of seconds to an integer, taking decimals into account
            $second = round((int) $match[6] + (int) $match[7] / pow(10, strlen($match[7])));
            return gmmktime($match[4], $match[5], $second, $match[2], $match[3], $match[1]) - $timezone;
        } else {
            return false;
        }
    }