com.rs3e.network.protocol.codec.js5.UpdateDecoder.java Source code

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Here is the source code for com.rs3e.network.protocol.codec.js5.UpdateDecoder.java

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/*
 * This file is part of Ieldor.
 *
 * Ieldor 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.
 *
 * Ieldor 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 Ieldor.  If not, see <http://www.gnu.org/licenses/>.
 */
package com.rs3e.network.protocol.codec.js5;

import com.rs3e.network.protocol.codec.ondemand.FileRequest;
import com.rs3e.network.protocol.messages.UpdateEncryptionMessage;
import com.rs3e.network.protocol.messages.UpdateVersionMessage;
import com.rs3e.utility.ByteBufUtils;

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

/**
 * An {@link ByteToMessageDecoder} that handles the update decoding.
 *
 * @author Thomas Le Godais <thomaslegodais@live.com>
 *
 */
public class UpdateDecoder extends ByteToMessageDecoder<Object> {

    /**
     * An simple enumeration used for handling update stages.
     *
     * @author Thomas Le Godais <thomaslegodais@live.com>
     *
     */
    public enum UpdateStage {
        READ_VERSION, READ_REQUEST
    };

    /**
     * The default update stage.
     */
    private UpdateStage updateStage = UpdateStage.READ_VERSION;

    /* (non-Javadoc)
     * @see io.netty.handler.codec.ByteToMessageDecoder#decode(io.netty.channel.ChannelHandlerContext, io.netty.buffer.ByteBuf)
     */
    @Override
    public Object decode(ChannelHandlerContext ctx, ByteBuf buf) throws Exception {
        if (buf.readableBytes() < 6)
            return null;

        if (updateStage == UpdateStage.READ_VERSION) {
            updateStage = UpdateStage.READ_REQUEST;
            int length = buf.readUnsignedByte();
            if (buf.readableBytes() >= length) {
                int version = buf.readInt();
                int subVersion = buf.readInt();
                String key = ByteBufUtils.readString(buf);
                return new UpdateVersionMessage(version, subVersion, key);
            }
        } else {
            int opcode = buf.readUnsignedByte();
            if (opcode == 0 || opcode == 1) {
                int type = buf.readUnsignedByte();
                int file = buf.readInt();
                return new FileRequest(opcode == 1, type, file);
            } else if (opcode == 4) {
                int key = buf.readUnsignedByte();
                buf.readerIndex(buf.readerIndex() + 2);
                return new UpdateEncryptionMessage(key);
            } else {
                buf.readerIndex(buf.readerIndex() + 5);
                return null;
            }
        }
        return null;
    }
}