Implementation code of php time and date tool class

/**
* Function: php time and date tool class
* Editor: bbs.it-home.org
*/
DateTimeUtils::addDate('2013-12-01',1,'y');
DateTimeUtils::getWeekDay('2013/10/01','/');
DateTimeUtils::isLeapYear('2013');
DateTimeUtils::timeFromNow(strtotime("2013-10-26 14:15:13"));
class DateTimeUtils {
    /**
     * Checks for leap year, returns true if it is. No 2-digit year check. Also
     * handles julian calendar correctly.
     * @param integer $year year to check
     * @return boolean true if is leap year
*/
    public static function isLeapYear($year)
    {
        $year = self::digitCheck($year);
        if ($year % 4 != 0)
        return false;

        if ($year % 400 == 0)
        return true;
        // if gregorian calendar (>1582), century not-divisible by 400 is not leap
        else if ($year > 1582 && $year % 100 == 0)
        return false;
        return true;
    }

    /**
     * Fix 2-digit years. Works for any century.
     * Assumes that if 2-digit is more than 30 years in future, then previous century.
     * @param integer $y year
     * @return integer change two digit year into multiple digits
*/
    protected static function digitCheck($y)
    {
        if ($y < 100){
            $yr = (integer) date("Y");
            $century = (integer) ($yr /100);

            if ($yr%100 > 50) {
                $c1 = $century + 1;
                $c0 = $century;
            } else {
                $c1 = $century;
                $c0 = $century - 1;
            }
            $c1 *= 100;
            // if 2-digit year is less than 30 years in future, set it to this century
            // otherwise if more than 30 years in future, then we set 2-digit year to the prev century.
            if (($y + $c1) < $yr+30) $y = $y + $c1;
            else $y = $y + $c0*100;
        }
        return $y;
    }

    /**
     * Returns 4-digit representation of the year.
     * @param integer $y year
     * @return integer 4-digit representation of the year
*/
    public static function get4DigitYear($y)
    {
        return self::digitCheck($y);
    }
    /**
     * Checks to see if the year, month, day are valid combination.
     * @param integer $y year
     * @param integer $m month
     * @param integer $d day
     * @return boolean true if valid date, semantic check only.
*/
    public static function isValidDate($y,$m,$d)
    {
        return checkdate($m, $d, $y);
    }

    public static function checkDate($date, $separator = "-") { //检查日期是否合法日期
        $dateArr = explode ($separator, $date);
        return self::isValidDate ($dateArr[0], $dateArr[1], $dateArr[2]);
    }
    /**
     * Checks to see if the hour, minute and second are valid.
     * @param integer $h hour
     * @param integer $m minute
     * @param integer $s second
     * @param boolean $hs24 whether the hours should be 0 through 23 (default) or 1 through 12.
     * @return boolean true if valid date, semantic check only.
     * @since 1.0.5
*/
    public static function isValidTime($h,$m,$s,$hs24=true)
    {
        if($hs24 && ($h < 0 || $h > 23) || !$hs24 && ($h < 1 || $h > 12)) return false;
        if($m > 59 || $m < 0) return false;
        if($s > 59 || $s < 0) return false;
        return true;
    }

    public static function checkTime($time, $separator = ":") { //检查时间是否合法时间
        $timeArr = explode($separator, $time);
        return self::isValidTime($timeArr[0], $timeArr[1],$timeArr[2]);
    }

    public static function addDate($date, $int, $unit = "d") { //日期的增加
        $value = array('y'=>'', 'm'=>'', 'd'=>'');
        $dateArr = explode ( "-", $date);
        if(array_key_exists($unit, $value)){
            $value[$unit] = $int;
        }else{
            return false;
        }
        return date ("Y-m-d", mktime (0, 0, 0, $dateArr[1] + $value['m'], $dateArr[2] + $value['d'], $dateArr[0] +$value['y']));
    }

 public static function addDateTime($date, $int, $unit = "d") { //Add date
 $value = array('y'=>'', 'm'=>'', 'd'=>'', 'h'=>'', 'i'=>'');
 $dateArr = preg_split ( "/-|s|:/", $date);
 if (array_key_exists($unit, $value)){
 $value[$unit] = $int;
 }else{
 return false;
 }
 return date ("Y-m-d H:i:s", mktime($dateArr[ 3]+ $value['h'], $dateArr[4]+ $value['i'], $dateArr[5], $dateArr[1] + $value['m'], $dateArr[2] + $value['d'], $dateArr[0] + $value['y']));
 }

 public static function addDayTimestamp($ntime, $aday) { //Get the days after the current time, The increasing unit of days is 1
 $dayst = 3600 * 24;
 $oktime = $ntime + ($aday * $dayst);
 return $oktime;
 }

 public static function dateDiff($begin, $end, $unit = "d") { //Time comparison function, returns the difference in seconds, minutes, hours or days between two dates
 $diff = strtotime($end) - strtotime($begin);
 switch($unit)
 {
 case "y": $retval = bcdiv($diff, (60 * 60 * 24 * 365)); break;
 case "m": $retval = bcdiv($diff, (60 * 60 * 24 * 30)); break;
 case "w": $retval = bcdiv($diff, (60 * 60 * 24 * 7)); break;
 case "d": $retval = bcdiv($diff, (60 * 60 * 24)); break;
 case "h": $retval = bcdiv($diff, (60 * 60)); break;
 case "i": $retval = bcdiv($diff, 60); break;
 case "s": $retval = $diff; break;
 }
 return $retval;
 }

 public static function getWeekDay($date, $separator = "-") { //Calculate the given date is Day of the week
 $dateArr = explode ($separator, $date);
 return date ("w", mktime (0, 0, 0, $dateArr[1], $dateArr[2], $dateArr[0])) ;
 }

 public static function timeFromNow($dateline) { //Let the date be displayed as: XX days XX years ago
 if(empty($dateline)) return false;
 $seconds = time() - $dateline;
 if($seconds < 60){
 return "1 minute ago";
 }elseif($seconds < 3600){
 return floor($seconds/60)."minutes ago";
 }elseif($seconds < ; 24*3600){
 return floor($seconds/3600)."hours ago";
 }elseif($seconds < 48*3600){
 return date("Yesterday H:i", $dateline)." ";
 }else{
 return date('Y-m-d', $dateline);
 }
 }

 public static function transDateToChs($date) {
 if (empty ($date)) return 'today';
 date_default_timezone_set('PRC');
 $dates = date ('Y year m month d day', strtotime ($date));
 return $dates;
 }

 // 08/31/2004 => 2004- 08-31
 public static function TransDateUI($datestr, $type = 'Y-m-d') {
 if ($datestr == Null)
 return Null;
 $target = $datestr;
 $arr_date = preg_split ( "/ //", $target);
 $monthstr = $arr_date[0];
 $daystr = $arr_date[1];
 $yearstr = $arr_date[2];
 $result = date ($type, mktime (0 , 0, 0, $monthstr, $daystr, $yearstr));
 return $result;
 }

 // 12/20/2004 10:55 AM => 2004-12-20 10:55:00
 public static function TransDateTimeUI($datestr, $type = 'Y-m-d H:i:s') {
 if ($datestr == Null)
 return Null;
 $target = $datestr;
 $arr_date = preg_split ( "// |s|:/", $target);
 $monthstr = $arr_date[0];
 $daystr = $arr_date[1];
 $yearstr = $arr_date[2];
 $hourstr = $arr_date[3] ;
 $minutesstr = $arr_date[4];
 $result = date ($type, mktime ($hourstr, $minutesstr, 0, $monthstr, $daystr, $yearstr));
 return $result;
 }
}
?>