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/*
* Copyright 2016 - 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.channel.Channel;
import org.traccar.BaseProtocolDecoder;
import org.traccar.DeviceSession;
import org.traccar.Protocol;
import org.traccar.helper.BitBuffer;
import org.traccar.helper.Parser;
import org.traccar.helper.PatternBuilder;
import org.traccar.model.Position;
import java.net.SocketAddress;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.regex.Pattern;
public class AisProtocolDecoder extends BaseProtocolDecoder {
public AisProtocolDecoder(Protocol protocol) {
super(protocol);
}
private static final Pattern PATTERN = new PatternBuilder()
.text("!AIVDM,")
.number("(d+),") // count
.number("(d+),") // index
.number("(d+)?,") // id
.expression(".,") // radio channel
.expression("([^,]+),") // payload
.any()
.compile();
private Position decodePayload(Channel channel, SocketAddress remoteAddress, BitBuffer buf) {
int type = buf.readUnsigned(6);
if (type == 1 || type == 2 || type == 3 || type == 18) {
buf.readUnsigned(2);
int mmsi = buf.readUnsigned(30);
DeviceSession deviceSession = getDeviceSession(channel, remoteAddress, String.valueOf(mmsi));
if (deviceSession == null) {
return null;
}
Position position = new Position(getProtocolName());
position.setDeviceId(deviceSession.getDeviceId());
position.setTime(new Date());
if (type == 18) {
buf.readUnsigned(8); // reserved
} else {
position.set(Position.KEY_STATUS, buf.readUnsigned(4));
position.set("turn", buf.readSigned(8));
}
position.setSpeed(buf.readUnsigned(10) * 0.1);
position.setValid(buf.readUnsigned(1) != 0);
position.setLongitude(buf.readSigned(28) * 0.0001 / 60.0);
position.setLatitude(buf.readSigned(27) * 0.0001 / 60.0);
position.setCourse(buf.readUnsigned(12) * 0.1);
position.set("heading", buf.readUnsigned(9));
return position;
}
return null;
}
@Override
protected Object decode(
Channel channel, SocketAddress remoteAddress, Object msg) throws Exception {
String[] sentences = ((String) msg).split("\\r\\n");
List<Position> positions = new ArrayList<>();
Map<Integer, BitBuffer> buffers = new HashMap<>();
for (String sentence : sentences) {
if (!sentence.isEmpty()) {
Parser parser = new Parser(PATTERN, sentence);
if (parser.matches()) {
int count = parser.nextInt(0);
int index = parser.nextInt(0);
int id = parser.nextInt(0);
Position position = null;
if (count == 1) {
BitBuffer bits = new BitBuffer();
bits.writeEncoded(parser.next().getBytes(StandardCharsets.US_ASCII));
position = decodePayload(channel, remoteAddress, bits);
} else {
BitBuffer bits = buffers.get(id);
if (bits == null) {
bits = new BitBuffer();
buffers.put(id, bits);
}
bits.writeEncoded(parser.next().getBytes(StandardCharsets.US_ASCII));
if (count == index) {
position = decodePayload(channel, remoteAddress, bits);
buffers.remove(id);
}
}
if (position != null) {
positions.add(position);
}
}
}
}
return positions;
}
}
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