The date-function doesn't return the korrect
week number of the year.

The 31'rd December 2001 is a Monday but belongs to
the first Week in 2002.

The Rule is:
The first January belongs to the first week of year,
if this day is a Monday,Tuesday,Wednesday or Thursday.



################## Script ###########################

<?

$cal = new calendar(mktime(0,0,0,1,1,2002));

?>

<table cellspacing="1" cellpadding="5" border="0">
  <tr>
    <td bgcolor="#e0e0e0"><b>KW</b></td>
    <td bgcolor="#e0e0e0"><b>Mo</b></td>
    <td bgcolor="#e0e0e0"><b>Di</b></td>
    <td bgcolor="#e0e0e0"><b>Mi</b></td>
    <td bgcolor="#e0e0e0"><b>Do</b></td>
    <td bgcolor="#e0e0e0"><b>Fr</b></td>
    <td bgcolor="#e0e0e0"><b>Sa</b></td>
    <td bgcolor="#e0e0e0"><b>So</b></td>
  </tr>
  <tr>

<? while($day_arr = $cal->pre_to_post_fetch_days()) { 
     if($day_arr['day_of_week'] == 1)
       echo '<td bgcolor="#e0e0e0">'.$day_arr[calendarweek].'</td>';?>
     <td bgcolor="#e0e0e0"><?=$day_arr['day_of_month']?></td>
<?   echo !$day_arr['day_of_week'] && $day_arr['day_of_month'] < $cal->last_day?"\n  </tr>\n  <tr>\n":'';
   }
?>
  </tr>
</table>

<?

$cal->reset_fetch_days();

echo '<pre>';
print_r($cal);
echo '<br><br>';
while($mycal = $cal->pre_to_post_fetch_days())
{
  print_r($mycal);
}
echo '</pre>';

/**********************************************************/

// Beim instanziiren der calendar-Klasse kann
// als Argument ein Unix-Timestamp ?bergeben werden.
// wenn nicht wird ein Timestamp des aktuellen Datums
// verwendet. 
class calendar
{

  // Eigenschaften der Klasse
  var $year, $month, $day;
  var $monthname,$monthname_de,$monthnamecut,$monthnamecut_de;
  var $calendarweek;
  var $stamp;
  var $last_day;

  // Z?hlervariable f?r die Funktion fetch_days()
  var $cnt = 0;

  // Adapter f?r die Umwandlung von einer Woche, welche mit dem
  // Sonntag beginnt in eine Woche, welche mit dem Montag beginnt
  var $adapter = array(0 => 6, 1 => 0,
                       2 => 1, 3 => 2,
                       4 => 3, 5 => 4,
                       6 => 5);

  // Diese Eigenschaften dienen zur Berechnung der Tage,
  // die zu einer vollst?ndigen Woche aber nicht zum
  // Monat geh?ren
  var $pre = 0, $post = 0;

  // Konstruktor f?r die Initialisierung der Eigenschaften
  function calendar($stamp = 0)
  {
    $months_de = array('Januar',    'Februar',
                       'M?rz',      'April',
                       'Mai',       'Juni',
                       'Juli',      'August',
                       'September', 'Oktober',
                       'November',  'Dezember');

    $this->stamp = $stamp?$stamp:date('U');

    $this->day             = date('j',$this->stamp);
    $this->month           = date('n',$this->stamp);
    $this->year            = date('Y',$this->stamp);

    $this->monthname       = date('F',$this->stamp);
    $this->monthnamecut    = date('M',$this->stamp);
    $this->monthname_de    = $months_de[date('n',$this->stamp)-1];
    $this->monthnamecut_de = substr($this->monthname_de,0,3);
    $this->calendarweek    = date('W',$this->stamp);

    $this->last_day        = date('t',$this->stamp);

    $this->pre             = $this->adapter[date('w',mktime(0,0,0,date('n',$this->stamp),1,$this->year))];
    $this->post            = 6 - $this->adapter[date('w',mktime(0,0,0,date('n',$this->stamp),$this->last_day,$this->year))];
  }

  // Methode zur Hilfe f?r die einfache Konstrucktion
  // eines Kalenders mit einer while-Schleife
  function fetch_days()
  {
    if(++$this->cnt <= $this->last_day)
      return $this->day_info(mktime(0,0,0,$this->month,$this->cnt,$this->year));

    else
      return 0;
  }

  function pre_to_post_fetch_days()
  {
    if(++$this->cnt - $this->pre <= $this->last_day + $this->post)
      return $this->day_info(mktime(0,0,0,$this->month,$this->cnt - $this->pre,$this->year));

    else
      return 0;
  }

  // Zur?cksetzen der Eigenschaft "cnt" um ein erneutes aufrufen
  // der Methode "fetch_days()" zu erm?glichen
  function reset_fetch_days() {
    $this->cnt = 0;
  }

  // Methode zur Abfrage von Informationen eines Tages
  function day_info($stamp = 0)
  {
    $stamp = $stamp?$stamp:$this->stamp;

    $weekdays_de = array('Sonntag',
                         'Montag',
                         'Dienstag',
                         'Mittwoch',
                         'Donnerstag',
                         'Freitag',
                         'Samstag');

      return array('day_of_week'    => date('w',$stamp),
                   'day_of_month'   => date('j',$stamp),
                   'day_of_year'    => date('z',$stamp)+1,
                   'weekday'        => date('l',$stamp),
                   'weekday_de'     => $weekdays_de[date('w',$stamp)],
                   'weekdaycuts'    => date('D',$stamp),
                   'weekdaycuts_de' => substr($weekdays_de[date('w',$stamp)],0,2),
                   'calendarweek'   => date('W',$stamp),
                   'timestamp'      => $stamp);
  }
}


?>