/*
 * Copyright (c) 2017 D3adspace
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

package de.d3adspace.skylla.commons.codec;

import de.d3adspace.skylla.commons.buffer.SkyllaBuffer;
import de.d3adspace.skylla.commons.protocol.Protocol;
import de.d3adspace.skylla.commons.protocol.packet.SkyllaPacket;
import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.ByteToMessageDecoder;

import java.util.List;

/**
 * Decoder for all Skyllapackets. The Decoder will try to read the packet id in order to create
 * a new one by that id and send the created packet through the Pipeline.
 *
 * @author Nathalie0hneHerz, Felix 'SasukeKawaii' Klauke
 */
public class SkyllaPacketDecoder extends ByteToMessageDecoder {

    /**
     * The protocol to handle packets for.
     */
    private final Protocol protocol;

    /**
     * Create a new decoder.
     *
     * @param protocol The protocol.
     */
    public SkyllaPacketDecoder(Protocol protocol) {
        this.protocol = protocol;
    }

    @Override
    protected void decode(ChannelHandlerContext channelHandlerContext, ByteBuf byteBuf,
                          List<Object> list) throws Exception {

        if (byteBuf.readInt() > 0) {
            byte packetId = byteBuf.readByte();

            SkyllaPacket packet = protocol.createPacket(packetId);
            packet.read(new SkyllaBuffer(byteBuf));

            list.add(packet);
        }
    }
}

/*
 * Copyright (c) 2017 D3adspace
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

package de.d3adspace.skylla.commons.codec;

import de.d3adspace.skylla.commons.buffer.SkyllaBuffer;
import de.d3adspace.skylla.commons.protocol.Protocol;
import de.d3adspace.skylla.commons.protocol.packet.SkyllaPacket;
import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.ByteToMessageDecoder;

import java.util.List;

/**
 * Decoder for all Skyllapackets. The Decoder will try to read the packet id in order to create
 * a new one by that id and send the created packet through the Pipeline.
 *
 * @author Nathalie0hneHerz, Felix 'SasukeKawaii' Klauke
 */
public class SkyllaPacketDecoder extends ByteToMessageDecoder {

    /**
     * The protocol to handle packets for.
     */
    private final Protocol protocol;

    /**
     * Create a new decoder.
     *
     * @param protocol The protocol.
     */
    public SkyllaPacketDecoder(Protocol protocol) {
        this.protocol = protocol;
    }

    @Override
    protected void decode(ChannelHandlerContext channelHandlerContext, ByteBuf byteBuf,
                          List<Object> list) {

        if (byteBuf.readInt() <= 0) {
            return;
        }

        byte packetId = byteBuf.readByte();

        SkyllaPacket packet = protocol.createPacket(packetId);
        packet.read(new SkyllaBuffer(byteBuf));

        list.add(packet);
    }
}

Simplify code flow.