PHP, see if date range is partly within another date range

Question

I've been looking forever for this, but the answer seems nowhere. Here's the problem:

Say, I've got two date ranges.

$daterange1 = 2012-04-20 till 2012-04-28 
$daterange2 = 2012-04-18 till 2012-05-01

Now, I'd like to know if daterange2 is within daterange1. But, as you can see, daterange2 only partly is within daterange1. Is there any way of getting 3 variables back, something like:

1. 2012-04-18 till 2012-04-20
2. 2012-04-20 till 2012-04-28
3. 2012-04-28 till 2012-05-01

I know it sounds a little vague, but I really don't know how to explain it different.

Answer 1

Here's an example using PHP's DateTime class. Note that if you pass an invalid date string to DateTime::__construct() the function will throw an exception, so you should implement a try/catch block if you're worried about this. Also, I use PHP's min and max functions so that it doesn't matter which order the dates are specified.

$daterange1 = array('2012-04-20', '2012-04-28');
$daterange2 = array('2012-04-18', '2012-05-01');

$range_min = new DateTime(min($daterange1));
$range_max = new DateTime(max($daterange1));

$start = new DateTime(min($daterange2));
$end = new DateTime(max($daterange2));

if ($start >= $range_min && $end <= $range_max) {
  echo 'woot!';
} else {
  echo 'doh!';
}