PHP - Counting Leap Days in Date Range - php

Question

I am trying to count the number of leap days within a date range.
This is what I have so far (adopted code from here)
<?php
$date_from = strtotime('2019-06-01');
$date_to = strtotime('2021-05-30');
$leapday_count = 0;
for($year=$date_from; $year<=$date_to; $year=strtotime('next year', $year)) {
if (date('L', $year)) {
$leapday_count++;
}
}
echo $leapday_count;
?>
Here is what I need help with:
The above code does only look at the years of the start and end date. For example it does not take into consideration if the start date is after Feb 29th. How can I make sure that it really takes the entire dates into consideration and not only the years of the dates?
Example expected result: 0 leap days between 2020-03-01 2024-02-28
Example expected result: 2 leap days between 2020-02-28 2024-03-01
Thanks in advance!

Answer 1

Stop doing date maths. It's hard.
Use datetime and diff
http://php.net/manual/en/datetime.diff.php
Example there
$datetime1 = new DateTime('2009-10-11');
$datetime2 = new DateTime('2009-10-13');
$interval = $datetime1->diff($datetime2);
echo $interval->format('%R%a days');
to exactly answer the question.
$start = new DateTime('2020-03-01');
$end = new DateTime('2024-02-28');
$interval = ("last day of feb next year");
$current = clone $start;
$leapYears = 0;
while ($current->modify("last day of feb") && $current <= $end) {
if ($current->format('d') == 29 && $current > $start) {
$leapYears++;
}
$current->modify("+1 year");
}