Date::date_rfc2822( string $date ): int|false

766    public function date_rfc2822(string $date)767    {768        static $pcre;769        if (!$pcre) {770            $wsp = '[\x09\x20]';771            $fws = '(?:' . $wsp . '+|' . $wsp . '*(?:\x0D\x0A' . $wsp . '+)+)';772            $optional_fws = $fws . '?';773            $day_name = $this->day_pcre;774            $month = $this->month_pcre;775            $day = '([0-9]{1,2})';776            $hour = $minute = $second = '([0-9]{2})';777            $year = '([0-9]{2,4})';778            $num_zone = '([+\-])([0-9]{2})([0-9]{2})';779            $character_zone = '([A-Z]{1,5})';780            $zone = '(?:' . $num_zone . '|' . $character_zone . ')';781            $pcre = '/(?:' . $optional_fws . $day_name . $optional_fws . ',)?' . $optional_fws . $day . $fws . $month . $fws . $year . $fws . $hour . $optional_fws . ':' . $optional_fws . $minute . '(?:' . $optional_fws . ':' . $optional_fws . $second . ')?' . $fws . $zone . '/i';782        }783        if (preg_match($pcre, $this->remove_rfc2822_comments($date), $match)) {784            /*785            Capturing subpatterns:786            1: Day name787            2: Day788            3: Month789            4: Year790            5: Hour791            6: Minute792            7: Second793            8: Timezone ±794            9: Timezone hours795            10: Timezone minutes796            11: Alphabetic timezone797            */798 799            $day = (int) $match[2];800            // Find the month number801            $month = $this->month[strtolower($match[3])];802            $year = (int) $match[4];803            $hour = (int) $match[5];804            $minute = (int) $match[6];805            // Second is optional, if it is empty set it to zero806            $second = (int) $match[7];807 808            $tz_sign = $match[8];809            $tz_hour = (int) $match[9];810            $tz_minute = (int) $match[10];811            $tz_code = isset($match[11]) ? strtoupper($match[11]) : '';812 813            // Numeric timezone814            if ($tz_sign !== '') {815                $timezone = $tz_hour * 3600;816                $timezone += $tz_minute * 60;817                if ($tz_sign === '-') {818                    $timezone = 0 - $timezone;819                }820            }821            // Character timezone822            elseif (isset($this->timezone[$tz_code])) {823                $timezone = $this->timezone[$tz_code];824            }825            // Assume everything else to be -0000826            else {827                $timezone = 0;828            }829 830            // Deal with 2/3 digit years831            if ($year < 50) {832                $year += 2000;833            } elseif ($year < 1000) {834                $year += 1900;835            }836 837            return gmmktime($hour, $minute, $second, $month, $day, $year) - $timezone;838        }839 840        return false;841    }