Return Date Difference for Two Time() Integers in PHP

I wanted to have a formatted time difference function that worked with two time() integer results and formatted the results, such as "X Years, Y Months, Z Weeks, etc.."  The following is that function, and it's designed to be modifiable, so you could easily cut out the standard Years / Months / Weeks / Days / Hours / Minutes / Seconds Format, and go to whatever format you prefer in whatever order you prefer.

Note:  This is apparently very useful for those using older versions of PHP, where the date_diff function isn't implemented!

<?php

        // Define Input
        // --------------------------------------

            // Example Time Difference
       
    $start_time_for_conversion = 0;
    $end_time_for_conversion = 123456;
   
    $difference_of_times = $end_time_for_conversion - $start_time_for_conversion;
   
    $time_difference_string = "";
   
    for($i_make_time = 6; $i_make_time > 0; $i_make_time--)
    {
        switch($i_make_time)
        {
                // Handle Minutes
                // ........................
               
            case '1';
                $unit_title = "Minute(s)";
                $unit_size = 60;
                break;
               
                // Handle Hours
                // ........................
               
            case '2';
                $unit_title = "Hour(s)";
                $unit_size = 3600;
                break;
               
                // Handle Days
                // ........................
               
            case '3';
                $unit_title = "Day(s)";
                $unit_size = 86400;
                break;
               
                // Handle Weeks
                // ........................
               
            case '4';
                $unit_title = "Week(s)";
                $unit_size = 604800;
                break;
               
                // Handle Months (31 Days)
                // ........................
               
            case '5';
                $unit_title = "Month(s)";
                $unit_size = 2678400;
                break;
               
                // Handle Years (365 Days)
                // ........................
               
            case '6';
                $unit_title = "Year(s)";
                $unit_size = 31536000;
                break;
        }
   
        if($difference_of_times > ($unit_size - 1))
        {
            $modulus_for_time_difference = $difference_of_times % $unit_size;
            $seconds_for_current_unit = $difference_of_times - $modulus_for_time_difference;
            $units_calculated = $seconds_for_current_unit / $unit_size;
            $difference_of_times = $modulus_for_time_difference;
   
            $time_difference_string .= "$units_calculated $unit_title, ";
        }
    }
   
        // Handle Seconds
        // ........................
   
    $time_difference_string .= "$difference_of_times Second(s)";

            // Example Result: "1 Day(s), 10 Hour(s), 17 Minute(s), 36 Second(s)"

?>

One other example: 123456789 = "3 Year(s), 10 Month(s), 3 Week(s), 2 Day(s), 21 Hour(s), 33 Minute(s), 9 Second(s)"

Official Function Page: http://www.php.net/manual/en/function.date-diff.php

// Note: All code appearing on the PHP Revolution blog by the blog owner is released under the Hacktivismo Enhanced-Source Software License Agreement (HESSLA), unless otherwise noted.  http://www.hacktivismo.com/about/hessla.php