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
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
|
/*
* Copyright 2017 - 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 org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.ChannelBuffers;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.handler.codec.frame.FrameDecoder;
import java.nio.charset.StandardCharsets;
public class WatchFrameDecoder extends FrameDecoder {
@Override
protected Object decode(
ChannelHandlerContext ctx, Channel channel, ChannelBuffer buf) throws Exception {
int idIndex = buf.indexOf(buf.readerIndex(), buf.writerIndex(), (byte) '*') + 1;
if (idIndex <= 0) {
return null;
}
int lengthIndex = buf.indexOf(idIndex, buf.writerIndex(), (byte) '*') + 1;
if (lengthIndex <= 0) {
return null;
}
int payloadIndex = buf.indexOf(lengthIndex, buf.writerIndex(), (byte) '*');
if (payloadIndex < 0) {
return null;
}
if (payloadIndex + 5 < buf.writerIndex() && buf.getByte(payloadIndex + 5) == '*'
&& buf.toString(payloadIndex + 1, 4, StandardCharsets.US_ASCII).matches("[0-9A-F]+")) {
lengthIndex = payloadIndex + 1;
payloadIndex = buf.indexOf(lengthIndex, buf.writerIndex(), (byte) '*');
if (payloadIndex < 0) {
return null;
}
}
int length = Integer.parseInt(
buf.toString(lengthIndex, payloadIndex - lengthIndex, StandardCharsets.US_ASCII), 16);
if (buf.readableBytes() >= payloadIndex + 1 + length + 1) {
ChannelBuffer frame = ChannelBuffers.dynamicBuffer();
int endIndex = buf.readerIndex() + payloadIndex + 1 + length + 1;
while (buf.readerIndex() < endIndex) {
byte b = buf.readByte();
if (b == 0x7D) {
switch (buf.readByte()) {
case 0x01:
frame.writeByte(0x7D);
break;
case 0x02:
frame.writeByte(0x5B);
break;
case 0x03:
frame.writeByte(0x5D);
break;
case 0x04:
frame.writeByte(0x2C);
break;
case 0x05:
frame.writeByte(0x2A);
break;
default:
throw new IllegalArgumentException();
}
} else {
frame.writeByte(b);
}
}
return frame;
}
return null;
}
}
|
