// Get user login ID from username and password
function user_login_id($username, $password) {
    $username = sanitize($username);
    $password = sha1($password);
    $data = mysql_select_single("SELECT `id` FROM `accounts` WHERE `name`='$username' AND `password`='$password' LIMIT 1;");
    if ($data !== false) return $data['id'];
    else return false;
}

// TFS 0.3+ compatibility.
function user_login_id_03($username, $password) {
    if (config('salt') === true) {
        if (user_exist($username)) {
            $user_id = user_id($username);
            $username = sanitize($username);

            $data = mysql_select_single("SELECT `salt`, `id`, `name`, `password` FROM `accounts` WHERE `id`='$user_id';");
            $salt = $data['salt'];
            if (!empty($salt)) $password = sha1($salt.$password);
            else $password = sha1($password);
            return ($data !== false && $data['name'] == $username && $data['password'] == $password) ? $data['id'] : false;
        } else return false;
    } else return user_login_id($username, $password);
}