LocalPacketCodec.java

/**
 * This file is part of Waarp Project.
 * 
 * Copyright 2009, Frederic Bregier, and individual contributors by the @author tags. See the
 * COPYRIGHT.txt in the distribution for a full listing of individual contributors.
 * 
 * All Waarp Project 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.
 * 
 * Waarp 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 Waarp . If not, see
 * <http://www.gnu.org/licenses/>.
 */
package org.waarp.openr66.protocol.localhandler.packet;

import java.util.List;

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

import org.waarp.openr66.protocol.exception.OpenR66ProtocolPacketException;

/**
 * Local Packet Decoder
 * 
 * @author Frederic Bregier
 */
public class LocalPacketCodec extends ByteToMessageCodec<AbstractLocalPacket> {

    @Override
    protected void decode(ChannelHandlerContext ctx, ByteBuf buf, List<Object> out) throws Exception {
        // Make sure if the length field was received.
        if (buf.readableBytes() < 4) {
            // The length field was not received yet - return null.
            // This method will be invoked again when more packets are
            // received and appended to the buffer.
            return;
        }
        AbstractLocalPacket newbuf = decodeNetworkPacket(buf);
        if (newbuf != null) {
            out.add(newbuf);
        }
    }

    public static AbstractLocalPacket decodeNetworkPacket(ByteBuf buf)
            throws OpenR66ProtocolPacketException {
        // Mark the current buffer position
        buf.markReaderIndex();
        // Read the length field
        final int length = buf.readInt();
        if (buf.readableBytes() < length) {
            buf.resetReaderIndex();
            return null;
        }
        // Now we can read the header
        // Header: Header length field (4 bytes) = Middle length field (4
        // bytes), End length field (4 bytes), type field (1 byte), ...
        final int middleLength = buf.readInt();
        final int endLength = buf.readInt();
        // check if the packet is complete
        if (middleLength + endLength + length - 8 > buf.readableBytes()) {
            buf.resetReaderIndex();
            return null;
        }
        // createPacketFromByteBuf read the buffer
        return LocalPacketFactory.createPacketFromByteBuf(length - 8,
                middleLength, endLength, buf);
    }

    @Override
    protected void encode(ChannelHandlerContext ctx, AbstractLocalPacket msg, ByteBuf out) throws Exception {
        /*if (msg instanceof ByteBuf) {
            out.writeBytes((ByteBuf) msg);
            return;
        }*/
        final ByteBuf buf = msg.getLocalPacket(null);
        out.writeBytes(buf);
        buf.release();
    }

}