/*
 * Copyright 2013 Anton Tananaev (anton.tananaev@gmail.com)
 *
 * 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.traccar.protocol;

import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.handler.codec.frame.FrameDecoder;
import org.traccar.helper.ChannelBufferTools;

public class WondexFrameDecoder extends FrameDecoder {
    
    private static final int KEEP_ALIVE_LENGTH = 6;

    @Override
    protected Object decode(
            ChannelHandlerContext ctx,
            Channel channel,
            ChannelBuffer buf) throws Exception {
        
        if (buf.readableBytes() < KEEP_ALIVE_LENGTH) {
            return null;
        }

        if (buf.getUnsignedByte(buf.readerIndex()) == 0xD0) {

            // Send response
            ChannelBuffer frame = buf.readBytes(KEEP_ALIVE_LENGTH);
            if (channel != null) {
                channel.write(frame);
            }

        } else {

            Integer index = ChannelBufferTools.find(buf, buf.readerIndex(), buf.readableBytes(), "\r\n");
            if (index != null) {
                ChannelBuffer frame = buf.readBytes(index - buf.readerIndex());
                buf.skipBytes(2);
                return frame;
            }
        
        }

        return null;
    }

}

@@ -1005,9 +1005,9 @@
 H = 
-6
+8
 ;%0A%0A 

Fix Wondex frame decoder