chamilo / chamilo-lms

     * @assert ('') === false

     * @assert ('xyzxyzxyz') === true

     */

    public static function is_username_available($username)

    {

        if (empty($username)) {

            return false;

        }

        $table_user = Database::get_main_table(TABLE_MAIN_USER);

        $sql = "SELECT username FROM $table_user

                WHERE username = '".Database::escape_string($username)."'";

        $res = Database::query($sql);

        return Database::num_rows($res) == 0;

    }

    /**

 * status of "6" (anonymous).

 * @return int  User ID of the anonymous user, or O if no anonymous user found

 */

function api_get_anonymous_id()

{

    $table = Database::get_main_table(TABLE_MAIN_USER);

    $sql = "SELECT user_id FROM $table WHERE status = ".ANONYMOUS;

    $res = Database::query($sql);

    if (Database::num_rows($res) > 0) {

        $row = Database::fetch_array($res);

        return $row['user_id'];

    }

    // No anonymous user was found.

    return 0;

}

/**

 * @param string $courseCode