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/*
* Copyright 2024 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.buffer.Unpooled;
import io.netty.channel.Channel;
import org.traccar.BaseProtocolDecoder;
import org.traccar.Protocol;
import org.traccar.helper.BitUtil;
import org.traccar.session.DeviceSession;
import java.lang.reflect.Method;
import java.net.SocketAddress;
public class FleetGuideProtocolDecoder extends BaseProtocolDecoder {
public FleetGuideProtocolDecoder(Protocol protocol) {
super(protocol);
}
public static final int MSG_DATA = 0x10;
public static final int MSG_HEARTBEAT = 0x1A;
public static final int MSG_RESPONSE = 0x1C;
@Override
protected Object decode(
Channel channel, SocketAddress remoteAddress, Object msg) throws Exception {
ByteBuf buf = (ByteBuf) msg;
buf.readUnsignedByte(); // signature
int options = buf.readUnsignedShort();
int length = BitUtil.to(options, 11);
DeviceSession deviceSession;
if (BitUtil.check(options, 11)) {
deviceSession = getDeviceSession(channel, remoteAddress, String.valueOf(buf.readUnsignedInt()));
} else {
deviceSession = getDeviceSession(channel, remoteAddress);
}
if (deviceSession == null) {
return null;
}
int type;
if (BitUtil.check(options, 12)) {
type = BitUtil.to(buf.readUnsignedByte(), 4);
} else {
type = 0;
}
if (BitUtil.check(options, 13)) {
buf.readUnsignedShort(); // acknowledgement
}
ByteBuf data;
if (BitUtil.check(options, 14)) {
data = decompress(buf.readSlice(length));
} else {
data = buf.readRetainedSlice(length);
}
data.release();
return null;
}
private ByteBuf decompress(ByteBuf input) throws ReflectiveOperationException {
Class<?> clazz = Class.forName("io.netty.handler.codec.compression.FastLz");
Method method = clazz.getDeclaredMethod(
"decompress", ByteBuf.class, int.class, int.class, ByteBuf.class, int.class, int.class);
ByteBuf output = Unpooled.buffer();
int result = (Integer) method.invoke(
null, input, input.readerIndex(), input.readableBytes(), output, 0, Integer.MAX_VALUE);
if (result <= 0) {
throw new IllegalArgumentException("FastLz decompression failed");
}
return output;
}
}
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