date_diff.php

<?php

function _dateDiff($date1, $date2) {
    $time1 = new DateTime($date1);
    $time2 = new DateTime($date2);
    $interval = $time1->diff($time2);

    $return = array();
    $return['days'] = $interval->days;
    $return['hours'] = $interval->h;
    $return['interval'] = $interval->invert == "-1" ? "negative" : "positive";

    return $return;
}


$diff = _dateDiff("2014-11-02 11:00:00","2014-11-01 13:00:00"));

# if first date is bigger than interval = positive