aboutsummaryrefslogtreecommitdiff
path: root/src/org/traccar/protocol/OrionFrameDecoder.java
blob: 92236225b0cbfb61b198b7c6cfbab538bc96c6c8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
/*
 * Copyright 2014 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;

public class OrionFrameDecoder extends FrameDecoder {

    @Override
    protected Object decode(
            ChannelHandlerContext ctx,
            Channel channel,
            ChannelBuffer buf) throws Exception {
        
        // Check minimum length
        if (buf.readableBytes() < 5) {
            return null;
        }
        
        int length = 2 + 2; // head and tail
        
        if (buf.getByte(buf.readerIndex()) == 0x78) {
            length += 1 + buf.getByte(buf.readerIndex() + 2);
        } else {
            length += 2 + buf.getShort(buf.readerIndex() + 2);
        }
        
        // Check length and return buffer
        if (buf.readableBytes() >= length) {
            return buf.readBytes(length);
        }

        return null;
    }

}