/*
 * Copyright 2015 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.StringFinder;

import java.nio.charset.StandardCharsets;

public class MegastekFrameDecoder extends FrameDecoder {

    @Override
    protected Object decode(
            ChannelHandlerContext ctx, Channel channel, ChannelBuffer buf) throws Exception {

        if (buf.readableBytes() < 10) {
            return null;
        }

        if (Character.isDigit(buf.getByte(buf.readerIndex()))) {
            int length = 4 + Integer.parseInt(buf.toString(buf.readerIndex(), 4, StandardCharsets.US_ASCII));
            if (buf.readableBytes() >= length) {
                return buf.readBytes(length);
            }
        } else {
            int delimiter = buf.indexOf(buf.readerIndex(), buf.writerIndex(), new StringFinder("\r\n"));
            if (delimiter != -1) {
                ChannelBuffer result = buf.readBytes(delimiter - buf.readerIndex());
                buf.skipBytes(2);
                return result;
            }
        }

        return null;
    }

}

@@ -14,16 +14,23 @@
 ht 2015 
+- 2016 
 Anton Ta
@@ -1525,100 +1525,391 @@
     
-int delimiter = buf.indexOf(buf.readerIndex(), buf.writerIndex(), new StringFinder(%22%5Cr%5Cn%22));
+while (buf.getByte(buf.readerIndex()) == '%5Cr' %7C%7C buf.getByte(buf.readerIndex()) == '%5Cn') %7B%0A                buf.skipBytes(1);%0A            %7D%0A            int delimiter = buf.indexOf(buf.readerIndex(), buf.writerIndex(), new StringFinder(%22%5Cr%5Cn%22));%0A            if (delimiter == -1) %7B%0A                delimiter = buf.indexOf(buf.readerIndex(), buf.writerIndex(), (byte) '!');%0A            %7D
 %0A   
@@ -2055,17 +2055,17 @@
 ipBytes(
-2
+1
 );%0A     

Improve Megastek frame decoder