Shorten Strings and leave the last word complete

shorten_strings.php

<?php

function shorten_string ($string, $string_max_length = 150) 
{
	if (empty($string) == true) 
	{
    	return('Es wurde kein String an die Function: shorten_string() übergeben!');
    } 
	else 
	{
    	$string_length = strlen($string);
        if ($string_length >= $string_max_length) 
		{
        	$string = preg_replace("/[^ ]*$/", '', substr($string, 0, $string_max_length));
            $string .= ' ...';
        }
        return ($string);
	}
}