org.l2junity.network.codecs.PacketDecoder.java Source code

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Here is the source code for org.l2junity.network.codecs.PacketDecoder.java

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/*
 * Copyright (C) 2004-2014 L2J Unity
 * 
 * This file is part of L2J Unity.
 * 
 * L2J Unity is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * L2J Unity 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 for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
package org.l2junity.network.codecs;

import java.nio.ByteOrder;
import java.util.List;

import org.l2junity.network.IConnectionState;
import org.l2junity.network.IIncomingPacket;
import org.l2junity.network.IIncomingPackets;
import org.l2junity.network.PacketReader;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.ByteToMessageDecoder;

/**
 * @author Nos
 * @param <T>
 */
public class PacketDecoder<T> extends ByteToMessageDecoder {
    private static final Logger LOGGER = LoggerFactory.getLogger(PacketDecoder.class);

    private final ByteOrder _byteOrder;
    private final IIncomingPackets<T>[] _incomingPackets;
    private final T _client;

    public PacketDecoder(ByteOrder byteOrder, IIncomingPackets<T>[] incomingPackets, T client) {
        _byteOrder = byteOrder;
        _incomingPackets = incomingPackets;
        _client = client;
    }

    @Override
    protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) {
        if ((in == null) || !in.isReadable()) {
            return;
        }

        if (in.order() != _byteOrder) {
            in = in.order(_byteOrder);
        }

        try {
            final short packetId = in.readUnsignedByte();
            if (packetId >= _incomingPackets.length) {
                LOGGER.debug("Unknown packet: {}", Integer.toHexString(packetId));
                return;
            }

            final IIncomingPackets<T> incomingPacket = _incomingPackets[packetId];
            if (incomingPacket == null) {
                LOGGER.debug("Unknown packet: {}", Integer.toHexString(packetId));
                return;
            }

            final IConnectionState connectionState = ctx.channel().attr(IConnectionState.ATTRIBUTE_KEY).get();
            if ((connectionState == null) || !incomingPacket.getConnectionStates().contains(connectionState)) {
                LOGGER.warn("{}: Connection at invalid state: {} Required States: {}", incomingPacket,
                        connectionState, incomingPacket.getConnectionStates());
                return;
            }

            final IIncomingPacket<T> packet = incomingPacket.newIncomingPacket();
            if ((packet != null) && packet.read(_client, new PacketReader(in))) {
                out.add(packet);
            }
        } finally {
            // We always consider that we read whole packet.
            in.readerIndex(in.writerIndex());
        }
    }
}