Calculate Date Of Easter Sunday

Description: Correctly calculate the date of Easter Sunday.

<?PHP
 
FUNCTION isLeapYear( $nYEAR ) {
  IF ((( $nYEAR % 4 == 0 ) AND !( $nYEAR % 100 == 0 )) AND ( $nYEAR % 400 != 0 )) {
    RETURN TRUE;
  } ELSE {
    RETURN FALSE;
  }
}
 
FUNCTION div( $a, $b ){
  RETURN( $a - ( $a % $b )) / $b;
}
 
FUNCTION easterSunday( $nYEAR ) {
  // The function is able to calculate the date of eastersunday back to the year 325,
  // but mktime() starts at 1970-01-01!
  IF ( $nYEAR < 1970 ) {
    $dtEasterSunday = MKTIME( 1,1,1,1,1,1970 );
  } ELSE {
    $nGZ = ( $nYEAR % 19 ) + 1;
    $nJHD = div( $nYEAR, 100 ) + 1;
    $nKSJ = div( 3 * $nJHD, 4 ) - 12;
    $nKORR = div( 8 * $nJHD + 5, 25 ) - 5;
    $nSO = div( 5 * $nYEAR, 4 ) - $nKSJ - 10;
    $nEPAKTE = (( 11 * $nGZ + 20 + $nKORR - $nKSJ ) % 30 );
    IF (( $nEPAKTE == 25 OR $nGZ == 11 ) AND $nEPAKTE == 24 ) {
      $nEPAKTE = $nEPAKTE + 1;
    }
    $nN = 44 - $nEPAKTE;
    IF( $nN < 21 ) {
      $nN = $nN + 30;
    }
    $nN = $nN + 7 - (( $nSO + $nN ) % 7 );
    $nN = $nN + isLeapYear( $nYEAR );
    $nN = $nN + 59;
 
    $nA = isLeapYear( $nYEAR );
    // Month
    $nNM = $nN;
    IF ( $nNM > ( 59 + $nA )) {
      $nNM = $nNM + 2 - $nA;
    }
    $nNM = $nNM + 91;
    $nMONTH = div( 20 * $nNM, 611 ) - 2;
 
    // Day
    $nNT = $nN;
    $nNT = $nN;
    IF ( $nNT > ( 59 + $nA )) {
      $nNT = $nNT + 2 - $nA;
    }
    $nNT = $nNT + 91;
    $nM = div( 20 * $nNT, 611 );
    $nDAY = $nNT - div( 611 * $nM, 20 );
 
    $dtEasterSunday = MKTIME( 0,0,0,$nMONTH,$nDAY,$nYEAR );
  }
  RETURN $dtEasterSunday;
}
 
?>

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