Creating a string exerpt elegantly

<?php
/**
 * Chop a string into a smaller string.
 *
 * @author      Aidan Lister <aidan@php.net>
 * @version     1.1.0
 * @link        http://aidanlister.com/2004/04/creating-a-string-exerpt-elegantly/
 * @param       mixed  $string   The string you want to shorten
 * @param       int    $length   The length you want to shorten the string to
 * @param       bool   $center   If true, chop in the middle of the string
 * @param       mixed  $append   String appended if it is shortened
 */
function str_chop($string, $length = 60, $center = false, $append = null)
{
    // Set the default append string

    if ($append === null) {
        $append = ($center === true) ? ' ... ' : ' ...';
    }
 
    // Get some measurements

    $len_string = strlen($string);
    $len_append = strlen($append);
 
    // If the string is longer than the maximum length, we need to chop it

    if ($len_string > $length) {
        // Check if we want to chop it in half

        if ($center === true) {
            // Get the lengths of each segment

            $len_start = $length / 2;
            $len_end = $len_start - $len_append;
 
            // Get each segment

            $seg_start = substr($string, 0, $len_start);
            $seg_end = substr($string, $len_string - $len_end, $len_end);
 
            // Stick them together

            $string = $seg_start . $append . $seg_end;
        } else {
            // Otherwise, just chop the end off

            $string = substr($string, 0, $length - $len_append) . $append;
        }
    }
 
    return $string;
}
?>

<?php
$longtext = "this is some really long text with long words that should be chopped";
$longlink = "http://thisisareally.longlink/with/lots/of/stupid/paths/";
 
// Chop at default length

echo str_chop($longtext);
echo "\n";
 
// Chop in the middle

echo str_chop($longtext, 60, true);
echo "\n";
 
// Chop a link

echo str_chop($longlink, 40, true);
echo "\n";
 
// Chop a link whirlpool style

echo "<a href=\"$longlink\">" . str_chop($longlink, 40, true) . '</a>';
?>