bbpress read more

function wptumble_show_read_more( $content = '', $topic_id = 0, $args = array() ) {
    global $bbp;
    global $mar_options;


    //default arguments
    $defaults = array(
        'separator' => '<hr />',
        'before'    => '<div class="wptumble-mark-as-read">',
        'after'     => '</div>'
    );
    $r = wp_parse_args( $args, $defaults );
    extract( $r );

    //verify topic id, get author id, and mark as read
    $topic_id   = bbp_get_topic_id          ( $topic_id );
    $user_id    = bbp_get_topic_author_id   ( $topic_id );

    if(bbp_is_single_topic() && get_post_type() == 'topic' && $mar_options['show_links'] == true) {

        if($mar_options['post_position'] == 'Top') {
            $content = mar_read_unread_links($mar_options[ 'read_text' ], $mar_options[ 'unread_text' ]) . $separator . $before . $content . $after;
        } else {
            $content = $content . $separator . $before . mar_read_unread_links($mar_options[ 'read_text' ], $mar_options[ 'unread_text' ]) . $after;
        }

    }
    return apply_filters( 'wptumble_show_read_more', $content, $topic_id, $separator );


}

if ( !is_admin() ) {
    add_filter( 'bbp_get_topic_content', 'wptumble_show_read_more', 1, 2 );
    add_filter( 'bbp_get_topic_content', 'bbp_topic_content_append_revisions',      1, 4 );
}