MIME::suffix PHP Method

    protected function suffix($filename)
    {
        if ($this->version == '1.0') {
            /* forward suffix tree */
            $queue = array(array('', $this->uint32_at(16)));
            while (!empty($queue)) {
                list($suffix, $pos) = array_shift($queue);
                list($n, $pos) = $this->nuint32_at($pos, 2);
                for ($i = 0; $i < $n; $i++, $pos += 16) {
                    $c = $this->uint32_at($pos);
                    $cur = $suffix . chr($c);
                    $idx = strrpos($filename, $cur);
                    if ($idx === FALSE) {
                        continue;
                    } else {
                        if ($idx + strlen($cur) == strlen($filename)) {
                            $type_off = $this->uint32_at($pos + 4);
                            if ($type_off == 0) {
                                continue;
                            }
                            return $this->string_at($type_off);
                        } else {
                            $queue[] = array($cur, $pos + 8);
                        }
                    }
                    $pos += 16;
                }
            }
        } else {
            /* reverse suffix tree */
            list($n, $pos) = $this->nuint32_at($this->uint32_at(16), 2);
            $suffix = '';
            for ($i = 0; $i < $n;) {
                $c = $this->uint32_at($pos);
                if ($c == 0) {
                    $type_off = $this->uint32_at($pos + 4);
                    return $this->string_at($type_off);
                } else {
                    if ($filename[strlen($filename) - strlen($suffix) - 1] == chr($c)) {
                        $suffix = chr($c) . $suffix;
                        /* FIXME: make unicode-aware? */
                        if (strlen($suffix) >= strlen($filename)) {
                            break;
                        }
                        list($n, $pos) = $this->nuint32_at($pos + 4, 2);
                        $i = 0;
                    } else {
                        $i++;
                        $pos += 12;
                    }
                }
            }
        }
        return NULL;
    }