<?php
function _leapYear ($year) {
    return ($year % 4 == 0 && $year % 100 != 0) || ($year % 400 == 0);
}

function _dayOfTheYear ($day, $month, $year) {
    $days = array (0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334);
    return $days[$month - 1] + ($month > 1 && _leapYear($year) ? 1 : 0) + ($day - 1);
}

function _mktime($day, $month, $year, $hour, $minute, $second) {
    $year = $year - 1970;
    $time = $seconde + $minute * 60 + $hour * 60 * 60 + _dayOfTheYear($day, $month, $year) * 60 * 60 * 24;
    $time += ((int)($year / 4) - (int)($year / 100) + (int)($year / 400)) * 24 * 60 * 60;
    $time += $year * 365 * 24 * 60 * 60;

    return $time;
}

//$phptimestamp = mktime (0, 0, 0, 10, 28, 2011);
$phptimestamp = mktime (0, 0, 0, 0, 0, 0);
$date = getdate($phptimestamp);

echo date ("L", $phptimestamp) ? "true" : "false", "\n";
echo _leapYear (0) ? "true" : "false", "\n";
echo "\n";

echo $date["yday"], "\n";
echo _dayOfTheYear(0, 0, 0), "\n";
echo "\n";

$timestamp = _mktime(0, 0, 0, 0, 0, 0);

echo $phptimestamp, "\n";
echo $timestamp, "\n";
echo "\n";

echo date ("Y-m-d H:i:s", $phptimestamp), "\n";
echo date ("Y-m-d H:i:s", $timestamp), "\n";

?>