Truncate a string to a certain length in PHP

truncate.php

<?php
/**
 * Truncate a string to a certain length if necessary,
 *               optionally splitting in the middle of a word, and
 *               appending the $etc string or inserting $etc into the middle.
 *
 * @param string $string input string
 * @param integer $length length of truncated text
 * @param string $etc end string
 * @param boolean $break_words truncate at word boundary
 * @param boolean $middle truncate in the middle of text
 *
 * @return string truncated string
 */
function truncate($string, $length = 80, $etc = '...', $break_words = false, $middle = false) {
    if ($length == 0) {
        return '';
    }
    if (mb_strlen($string, 'UTF-8') > $length) {
        $length -= min($length, mb_strlen($etc, 'UTF-8'));
        if (!$break_words && !$middle) {
            $string = preg_replace('/\s+?(\S+)?$/u', '', mb_substr($string, 0, $length + 1, 'UTF-8'));
        }
        if (!$middle) {
            return mb_substr($string, 0, $length, 'UTF-8') . $etc;
        }

        return mb_substr($string, 0, $length / 2, 'UTF-8') . $etc . mb_substr($string,
                                                                              -$length / 2,
                                                                              $length,
                                                                              'UTF-8');
    }

    return $string;
}