/*
 * Copyright 2014 Open Networking Laboratory
 *
 * 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.onlab.packet;

import java.nio.ByteBuffer;

import static com.google.common.base.MoreObjects.toStringHelper;
import static org.onlab.packet.PacketUtils.*;

/**
 * This class represents an Link Local Control header that is used in Ethernet
 * 802.3.
 */
public class LLC extends BasePacket {

    public static final byte LLC_HEADER_LENGTH = 3;

    private byte dsap = 0;
    private byte ssap = 0;
    private byte ctrl = 0;

    public byte getDsap() {
        return this.dsap;
    }

    public void setDsap(final byte dsap) {
        this.dsap = dsap;
    }

    public byte getSsap() {
        return this.ssap;
    }

    public void setSsap(final byte ssap) {
        this.ssap = ssap;
    }

    public byte getCtrl() {
        return this.ctrl;
    }

    public void setCtrl(final byte ctrl) {
        this.ctrl = ctrl;
    }

    @Override
    public byte[] serialize() {
        final byte[] data = new byte[3];
        final ByteBuffer bb = ByteBuffer.wrap(data);
        bb.put(this.dsap);
        bb.put(this.ssap);
        bb.put(this.ctrl);
        return data;
    }

    @Override
    public IPacket deserialize(final byte[] data, final int offset,
                               final int length) {
        final ByteBuffer bb = ByteBuffer.wrap(data, offset, length);
        this.dsap = bb.get();
        this.ssap = bb.get();
        this.ctrl = bb.get();
        return this;
    }

    /**
     * Deserializer function for LLC packets.
     *
     * @return deserializer function
     */
    public static Deserializer<LLC> deserializer() {
        return (data, offset, length) -> {
            checkInput(data, offset, length, LLC_HEADER_LENGTH);

            ByteBuffer bb = ByteBuffer.wrap(data, offset, length);
            LLC llc = new LLC();

            llc.dsap = bb.get();
            llc.ssap = bb.get();
            llc.ctrl = bb.get();

            return llc;
        };
    }

    @Override
    public String toString() {
        return toStringHelper(getClass())
                .add("dsap", Byte.toString(dsap))
                .add("ssap", Byte.toString(ssap))
                .add("ctrl", Byte.toString(ctrl))
                .toString();
    }
}