Merge "LE Audio: add ContentControlIdKeeper"

/*

 * Copyright 2021 HIMSA II K/S - www.himsa.com.

 * Represented by EHIMA - www.ehima.com

 *

 * 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 com.android.le_audio;

import java.util.SortedSet;

import java.util.TreeSet;

/**

 * This class keeps Content Control Ids for LE Audio profiles.

 */

public class ContentControlIdKeeper {

    public static final int CCID_INVALID = 0;

    public static final int CCID_MIN = 0x01;

    public static final int CCID_MAX = 0xFF;

    private static SortedSet<Integer> sAssignedCcidList = new TreeSet();

    public static synchronized int acquireCcid() {

        int ccid = CCID_INVALID;

        if (sAssignedCcidList.size() == 0) {

            ccid = CCID_MIN;

        } else if (sAssignedCcidList.last() < CCID_MAX) {

            ccid = sAssignedCcidList.last() + 1;

        } else if (sAssignedCcidList.first() > CCID_MIN) {

            ccid = sAssignedCcidList.first() - 1;

        } else {

            int first_ccid_avail = sAssignedCcidList.first() + 1;

            while (first_ccid_avail < CCID_MAX - 1) {

                if (!sAssignedCcidList.contains(first_ccid_avail)) {

                    ccid = first_ccid_avail;

                    break;

                }

                first_ccid_avail++;

            }

        }

        if (ccid != CCID_INVALID) sAssignedCcidList.add(ccid);

        return ccid;

    }

    public static synchronized void releaseCcid(int value) {

        sAssignedCcidList.remove(value);

    }

}