<?php
define("TIME_ZONE", 1);

function isLeapYear($year) {
    return $year % 400 == 0 || ($year % 4 == 0 && $year % 100 != 0);
}

function mktimeEx($hour, $minute, $second, $day, $month, $year) {
    $days_of_month = [
            0   * 86400, 31  * 86400, 59  * 86400,
            90  * 86400, 120 * 86400, 151 * 86400,
            181 * 86400, 212 * 86400, 243 * 86400,
            273 * 86400, 304 * 86400, 334 * 86400
        ];

    $lMonth;
    $lYear;
    $lMonthS;
    $lYearS;

    if ($year != $lYear) {
        $year -= 1970;
        // Subtract the UNIX epoch.
        // Get full years.
        $lYearS = $year * 31536000;
        // Add leap years.
        $lYearS += 86400 * ($year / 4);
        // Remove false leap years.
        // Adjust for the odd start point.
        $year += 70;
        // Remove all hundreds.
        $lYearS -= ($year / 100) * 86400;
        // Add the 400s back.
        $year += 300;
        $lYearS += ($year / 400) * 86400;
        $year += 1600; // 1970 - 370
        $lYear = $year;
    }

    // Adjust to 0 start.
    if ($month != $lMonth) {
        $month--;
        $lMonthS = $days_of_month[$month];
        if ((isLeapYear($year) && $month >= 2) || isLeapYear($year - 1)) {
            // Add an extra day.
            $lMonthS += 86400;
        }
        $lMonth = $month + 1;
    }

    $day = ($day - 1) * 86400;
    $hour = ($hour - (0 + TIME_ZONE)) * 3600;
    $minute = $minute * 60;

    return $lYearS + $lMonthS + $day + $hour + $minute + $second;
}

for ($year = 2000; $year <= 2030; $year++) {
    for ($month = 1; $month <= 12; $month++) {
        for ($day = 1; $day <= 31; $day++) {
            if ($month == 2 && $day > 28) {
                continue;
            } else if ($day > 30) {
                if ($month == 4 || $month == 6 || $month == 9 || $month == 11) {
                    continue;
                }
            }

            $mktimeEx = mktimeEx(0, 0, 0, $day, $month, $year);
            $mktime = mktime(0, 0, 0, $month, $day, $year);

            echo $day . "." . $month . "." . $year . ": " . $mktime . "-" . $mktimeEx . "-" . ($mktime == $mktimeEx ? "+" : "x") . "<br>";

            /*if ($mktimeEx != $mktime) {
                echo $day . "." . $month . "." . $year . ": " . $mktime . "-" . $mktimeEx . " " . ($mktime == $mktimeEx ? "+" : "x") . "<br>";
            }*/
        }
    }
}
?>