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authorAnton Tananaev <anton@traccar.org>2024-01-31 08:24:52 -0800
committerAnton Tananaev <anton@traccar.org>2024-01-31 08:25:00 -0800
commitcff42765e3ab39dccb73ea7d49f4b6270fe9931a (patch)
tree73ce8d8ed4a73366dfd092f75f816724a326f0d6 /src/main/java/org
parent5c1a520850acced42cf81b3974134067182b6a99 (diff)
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Add LZ77 decompression algorithm
Diffstat (limited to 'src/main/java/org')
-rw-r--r--src/main/java/org/traccar/protocol/FleetGuideProtocolDecoder.java49
1 files changed, 37 insertions, 12 deletions
diff --git a/src/main/java/org/traccar/protocol/FleetGuideProtocolDecoder.java b/src/main/java/org/traccar/protocol/FleetGuideProtocolDecoder.java
index 4e5de2b3e..94d837145 100644
--- a/src/main/java/org/traccar/protocol/FleetGuideProtocolDecoder.java
+++ b/src/main/java/org/traccar/protocol/FleetGuideProtocolDecoder.java
@@ -23,7 +23,6 @@ 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 {
@@ -79,21 +78,47 @@ public class FleetGuideProtocolDecoder extends BaseProtocolDecoder {
return null;
}
- private ByteBuf decompress(ByteBuf input) throws ReflectiveOperationException {
+ private int readVarSize(ByteBuf buf) {
+ int b;
+ int y = 0;
+ do {
+ b = buf.readUnsignedByte();
+ y = (y << 7) | (b & 0x0000007f);
+ } while ((b & 0x00000080) > 0);
- 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);
- method.setAccessible(true);
+ return y;
+ }
+
+ private ByteBuf decompress(ByteBuf in) {
+
+ ByteBuf out = Unpooled.buffer();
- 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");
+ if (in.readableBytes() < 1) {
+ return out;
}
- return output;
+ int marker = in.readUnsignedByte();
+
+ do {
+ int symbol = in.readUnsignedByte();
+ if (symbol == marker) {
+ if (in.getUnsignedByte(in.readerIndex()) == 0) {
+ out.writeByte(marker);
+ in.skipBytes(1);
+ } else {
+ int length = readVarSize(in);
+ int offset = readVarSize(in);
+
+ for (int i = 0; i < length; i++) {
+ out.writeByte(out.getUnsignedByte(out.writerIndex() - offset));
+ }
+ }
+ } else {
+ out.writeByte(symbol);
+ }
+ } while (in.isReadable());
+
+ return out;
}
}