aboutsummaryrefslogtreecommitdiff
path: root/src/org/traccar/protocol/Pt502FrameDecoder.java
blob: 9c798944658bba4d8575e406412f77f29e1cf12d (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
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
/*
 * Copyright 2014 - 2018 Anton Tananaev (anton@traccar.org)
 *
 * 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 io.netty.buffer.ByteBuf;
import io.netty.channel.Channel;
import io.netty.channel.ChannelHandlerContext;
import org.traccar.BaseFrameDecoder;

import java.nio.charset.StandardCharsets;

public class Pt502FrameDecoder extends BaseFrameDecoder {

    private static final int BINARY_HEADER = 5;

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

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

        if (buf.getUnsignedByte(buf.readerIndex()) == 0xbf
                && buf.toString(buf.readerIndex() + BINARY_HEADER, 4, StandardCharsets.US_ASCII).equals("$PHD")) {

            int length = buf.getUnsignedShortLE(buf.readerIndex() + 3);
            if (buf.readableBytes() >= length) {
                buf.skipBytes(BINARY_HEADER);
                ByteBuf result = buf.readBytes(length - BINARY_HEADER - 2);
                buf.skipBytes(2); // line break
                return result;
            }

        } else {

            if (buf.getUnsignedByte(buf.readerIndex()) == 0xbf) {
                buf.skipBytes(BINARY_HEADER);
            }

            int index = buf.indexOf(buf.readerIndex(), buf.writerIndex(), (byte) '\r');
            if (index < 0) {
                index = buf.indexOf(buf.readerIndex(), buf.writerIndex(), (byte) '\n');
            }

            if (index > 0) {
                ByteBuf result = buf.readBytes(index - buf.readerIndex());
                while (buf.isReadable()
                        && (buf.getByte(buf.readerIndex()) == '\r' || buf.getByte(buf.readerIndex()) == '\n')) {
                    buf.skipBytes(1);
                }
                return result;
            }

        }

        return null;
    }

}