/*

 * Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

/*

 * Utilities for WebSocket status codes.

 *

 *     1. https://tools.ietf.org/html/rfc6455#section-7.4

 *     2. http://www.iana.org/assignments/websocket/websocket.xhtml#close-code-number

 */

final class StatusCodes {

    static final int PROTOCOL_ERROR    = 1002;

    static final int NO_STATUS_CODE    = 1005;

    static final int CLOSED_ABNORMALLY = 1006;

    static final int NOT_CONSISTENT    = 1007;

    private StatusCodes() { }

    static boolean isLegalToSendFromClient(int code) {

        if (!isLegal(code)) {

            return false;

        }

        // Codes from unreserved range

        if (code > 4999) {

            return false;

        }

        // Codes below are not allowed to be sent using a WebSocket client API

        switch (code) {

            case PROTOCOL_ERROR:

            case NOT_CONSISTENT:

            case 1003:

            case 1009:

            case 1010:

            case 1012:  // code sent by servers

            case 1013:  // code sent by servers

            case 1014:  // code sent by servers

                return false;

            default:

                return true;

        }

    }

    static boolean isLegalToReceiveFromServer(int code) {

        if (!isLegal(code)) {

            return false;

        }

        return code != 1010;  // code sent by clients

    }

    private static boolean isLegal(int code) {

        // 2-byte unsigned integer excluding first 1000 numbers from the range

        // [0, 999] which are never used

        if (code < 1000 || code > 65535) {

            return false;

        }

        // Codes from the range below has no known meaning under the WebSocket

        // specification (i.e. unassigned/undefined)

        if ((code >= 1016 && code <= 2999) || code == 1004) {

            return false;

        }

        // Codes below cannot appear on the wire. It's always an error either

        // to send a frame with such a code or to receive one.

        switch (code) {

            case NO_STATUS_CODE:

            case CLOSED_ABNORMALLY:

            case 1015:

                return false;

            default:

                return true;

        }

    }

}