AppCookie.java

/*
 * Copyright (c) 2011,2013 Big Switch Networks, Inc.
 *
 * Licensed under the Eclipse Public License, Version 1.0 (the
 * "License"); you may not use this file except in compliance with the
 * License. You may obtain a copy of the License at
 *
 *      http://www.eclipse.org/legal/epl-v10.html
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * permissions and limitations under the License.
 *
 * This file incorporates work covered by the following copyright and
 * permission notice:
 *
 *    Originally created by David Erickson, Stanford University 
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the
 *    License. You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing,
 *    software distributed under the License is distributed on an "AS
 *    IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
 *    express or implied. See the License for the specific language
 *    governing permissions and limitations under the License. 
 */

package org.sdnplatform.core.util;

/***
 * FIXME Need a system for registering/binding applications to a unique ID
 * 
 * @author capveg
 *
 */

public class AppCookie {
    static final int APP_ID_BITS = 12;
    static final int APP_ID_SHIFT = (64 - APP_ID_BITS);
    // we have bits 13-31 unused here ... that's ok!
    static final int USER_BITS = 32;
    static final int USER_SHIFT = 0;


    /**
     * Encapsulate an application ID and a user block of stuff into a cookie
     * 
     * @param application An ID to identify the application
     * @param user Some application specific data
     * @return a cookie for use in OFFlowMod.setCookie()
     */
    
    static public long makeCookie(int application, int user) {
        return ((application & ((1L << APP_ID_BITS) - 1)) << APP_ID_SHIFT) | user;
    }
    
    static public int extractApp(long cookie) {
        return (int)((cookie>> APP_ID_SHIFT) & ((1L << APP_ID_BITS) - 1));
    }
    
    static public int extractUser(long cookie) {
        return (int)((cookie>> USER_SHIFT) & ((1L << USER_BITS) - 1));
    }
}