写作范围内的孔

I'm trying to write a program that relies on date ranges. I am trying to be able to alert users when there are holes in their ranges but I need a reliable way to find those, and to be able to handle them effectively.

My solution was to change any dates so that any day inserted into the app is rewritten so it is that day at noon. Here is the code for that:

    public function reformDate($date){
        return strtotime(date("F j, Y", $date)." 12:00pm");
    }

This would allow me to deal with a more regular and consistent dataset. Because I only had to see how many days they were apart, rather than seeing how many seconds they were apart and making a decision whether that time quantity represented an intentional gap or not...

I saw, however, when you put something in for today at noon, then if you put something tomorrow at noon, since the values are the same, and based on my restriction:

Select * from times where :date between start and end

It triggers a response. My solution for this was to just add one to the start variable, and detract one from the end variable, so I can easily check if there are overlap by asking if the difference between the start of one and end of another is more than 2.

Anyway, my question is: is this a good way to do this? I'm particularly worried about the number 2 - do I need to worry about using such small units of time (that is unix time, by the way). Alternately, should I create a test that if two time units overlap perfectly - they should be accepted?