php optimization needed: date range -> months - php

Question

(fixed and working fine now, but if anyone still wants to refactor, leave a note)
This is a stripped down version of a function I have which iterates over a date range and assigns a unique integer to each...
When working with large datasets, running this several times over different date ranges, I'm getting a fatal error, assigning too much memory to the script and it dies in this loop...
Fatal error: Allowed memory size of 268435456 bytes exhausted
fixed, was an issue with the iteration not taking into account the potential daylight-savings-time
So, I was wondering if someone could recommend a more optimal way of generating this list of months/ints...
It must allow me to start the Int at whatever number I like and
<?php
// updated: 2010.11.04 with Qwerty's recommendations
// for fixing daylight savings time issue
function monthIterate($monthInt, $startDate, $stopDate) {
$epoch = $startMain = strtotime($startDate);
$stopMain = strtotime($stopDate);
while ($epoch <= $stopMain) {
// get the start/stop dates for "this month"
$start = date("Y-m-01", $epoch);
$stop = date("Y-m-t", $epoch);
// uniqueID for the month
$monthKey = "Month#-".str_pad($monthInt, 3, "0", STR_PAD_LEFT);
$months[$monthKey] = compact('start', 'stop');
// move forward in loop, +1 day should get us to the next month
$epoch = strtotime($stop);
$currentMonth = $nextMonth = date('m', $epoch);
while ($currentMonth == $nextMonth) {
$epoch = $epoch + 86400;
$nextMonth = date('m', $epoch);
}
$monthInt++;
}
return $months;
}
?>

Answer 1

Looks like your function goes in endless loop because of extra hour in light saving time.
echo date('Y-m-d H:i:s', strtotime('2010-10-31') + 60*60*2); // adding 2 hours
echo date('Y-m-d H:i:s', strtotime('2010-10-31') + 60*60*3); // adding 3 hours
both will output 2010-10-31 02:00:00. Thus strtotime('2010-10-31') + 86400 is actually 2010-10-31 23:00:00, but not next day.
So you should add more than 86400 seconds to be sure you switched to next day :-)

Answer 2

I think your array index gets too crazy.
ie :
[Month#-Month#-Month#-Month#-Month#-Month#-Month#-Month#-Month#-Month#-Month#-Month#-Month#-Month#-Month#-Month#-Month#-Month#-Month#-Month#-Month#-Month#-Month#-Month#-123] => Array
(
[start] => 2011-12-01
[stop] => 2011-12-31
)
I would move your "$monthInt = "Month#-".str_pad($monthInt, 3, "0", STR_PAD_LEFT);" lines outside your loop.
<?php
function monthIterate($monthInt, $startDate, $stopDate) {
$monthInt = "Month#-".str_pad($monthInt, 3, "0", STR_PAD_LEFT); <--
$epoch = $startMain = strtotime($startDate);
$stopMain = strtotime($stopDate);
while ($epoch <= $stopMain) {
// get the start/stop dates for "this month"
$start = date("Y-m-01", $epoch);
$stop = date("Y-m-t", $epoch);
// uniqueID for the month
$months[$monthInt] = compact('start', 'stop');
// move forward in loop, +1 day should get us to the next month
$epoch = strtotime($stop) + 86400;
$monthInt++;
}
return $months;
}?>