[SOLVED] first day in fisrt week

there is function in php that let me know the first day in WEEK 1 ?

for exemple like this year  (2008-01-01) is day 2

so week 1 in 2008 start in 2007-12-31

and same for last week because the end of week 52  of 2008 is 2008-12-28  and

week 1 in 2009 start in 2008-12-29

there isn't a function for it...but logically...this makes sense (to me):

<?php
  $year = 2009;
  $start = mktime(0,0,0,1,2-date('w',mktime(0,0,0,1,1,$year)),$year);
  print date('r',$start);
?>

i found this and give strat say week and end day of week

function weekDayToTime($week, $year, $dayOfWeek = 1) { 
  //dayOfWeek: 0=sunday, 1=monday, ..., 6=saturday 
  $dayOfWeekRef = date("w", mktime (0,0,0,1,4,$year)); 
  if ($dayOfWeekRef == 0) $dayOfWeekRef = 7; 
  $resultTime = mktime(0,0,0,1,4,$year) + ((($week - 1) * 7 + ($dayOfWeek - $dayOfWeekRef)) * 86400); 
  $resultTime = cleanTime($resultTime);  //Cleaning daylight saving time hours 
  return $resultTime; 
}; 

function cleanTime($time) { 
  //This function strips all hours, minutes and seconds from time. 
  //For example useful of cleaning up DST hours from time 
  $cleanTime = mktime(0,0,0,date("m", $time),date("d", $time),date("Y", $time)); 
  return $cleanTime; 
}