note 87858 deleted from function.strtotime by danbrown
| From: | danbrown@php.net | Date: | Sat, 27 Dec 2008 17:45:26 +0000 |
| Subject: | note 87858 deleted from function.strtotime by danbrown | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-148579@lists.php.net to get a copy of this message | ||
Note Submitter: wck555 at gmailgmail dot dot comcom
----
Bug #44073 illustrates a difference of opinion on what "+1 month" means.
http://bugs.php.net/bug.php?id=44073
In my application, I need to use tuxedobob's interpretation of "+1 month". That is:
"3/31/2008 + 1 month" = "4/30/2008" (not "5/1/2008"). Below is a
function AddMonths() that adds months to a give date using this interpretation. There is probably a
simpler way to do this, but I need many of the intermediate functions in other places.
<?
// AddMonths()
//
// This function adds the given number of months to $dtDate. If the resulting
// date is beyond the end of the resulting month (ex: 1/31/2000 + 1 month = 2/31/2001
// which is invalid), the resulting date is rolled back to the last day of the
// month (ex: 1/31/2000 + 1 month = 2/28/2001)
//
// PARAMETERS:
// $dtDate - starting date
// $months - number of months to add
//
// RETURN: (DateTime) $dtDate + $months
function AddMonths($dtDate, $months)
{
$numericDate = iDateToNumeric($dtDate) + $months;
$month = ($numericDate % 12) + 1;
$year = (floor($numericDate/12));
$day = min($dtDate->format("j"), iDaysInMonth($month, $year));
return(new DateTime("$month/$day/$year"));
}
// iDaysInMonth()
//
// This function determines the number of days in a given month, year
//
// PARAMETERS:
// $month - The month
// $year - The year
//
// RETURN: Number of days in given month/year
Function iDaysInMonth($month, $year)
{
switch($month) {
case 4:
case 6:
case 9:
case 11:
return(30);
break;
case 2:
// --- February - need to check for leapyear
if(IsLeapYear($year))
{
return(29);
}
else
{
return(28);
}
break;
default:
return(31);
break;
}
}
// IsLeapYear()
//
// This function determines if the specified year is a leap year
//
// PARAMETERS:
// $year - the year
//
// RETURN: True of $year is a leap year
Function IsLeapYear($year)
{
if ($year % 4 != 0)
{
return false;
}
else
{
if ($year % 100 != 0)
{
return true;
}
else
{
if ($year % 400 != 0)
{
return false;
}
else
{
return true;
}
}
}
}
// iDateToNumeric()
//
// This function converts a date to an integer numeric date value. The value
// returned by this function is the number of months since 0 AD.
//
// PARAMETERS:
// Date dtDate - date to be converted
//
// RETURN: numeric date value
function iDateToNumeric($dtDate)
{
return($dtDate->format("Y")*12 + $dtDate->format("n") - 1);
}
// dtNumericToDate()
//
// This function converts a numeric date value back to a standard date.
//
// PARAMETERS:
// Date iNumeric - numeric date to be converted
//
// RETURN: date value
function dtNumericToDate($iNumeric)
{
return(new DateTime(($iNumeric%12) + 1 . "/1/" . floor($iNumeric/12)));
}
?>