Date::date_rfc850( string $date ): int|false

850    public function date_rfc850(string $date)851    {852        static $pcre;853        if (!$pcre) {854            $space = '[\x09\x20]+';855            $day_name = $this->day_pcre;856            $month = $this->month_pcre;857            $day = '([0-9]{1,2})';858            $year = $hour = $minute = $second = '([0-9]{2})';859            $zone = '([A-Z]{1,5})';860            $pcre = '/^' . $day_name . ',' . $space . $day . '-' . $month . '-' . $year . $space . $hour . ':' . $minute . ':' . $second . $space . $zone . '$/i';861        }862        if (preg_match($pcre, $date, $match)) {863            /*864            Capturing subpatterns:865            1: Day name866            2: Day867            3: Month868            4: Year869            5: Hour870            6: Minute871            7: Second872            8: Timezone873            */874 875            $day = (int) $match[2];876            // Month877            $month = $this->month[strtolower($match[3])];878            $year = (int) $match[4];879            $hour = (int) $match[5];880            $minute = (int) $match[6];881            // Second is optional, if it is empty set it to zero882            $second = (int) $match[7];883 884            $tz_code = strtoupper($match[8]);885 886            // Character timezone887            if (isset($this->timezone[$tz_code])) {888                $timezone = $this->timezone[$tz_code];889            }890            // Assume everything else to be -0000891            else {892                $timezone = 0;893            }894 895            // Deal with 2 digit year896            if ($year < 50) {897                $year += 2000;898            } else {899                $year += 1900;900            }901 902            return gmmktime($hour, $minute, $second, $month, $day, $year) - $timezone;903        }904 905        return false;906    }