From 032d02b584553f4374c4bc6ae9f7c8e819595c42 Mon Sep 17 00:00:00 2001
From: Stefan Clark <stefanclark@gmail.com>
Date: Mon, 25 Jul 2022 06:50:59 +0000
Subject: Xexun2 Encoder - Initial Code

---
 .../traccar/protocol/Xexun2ProtocolEncoder.java    | 121 +++++++++++++++++++++
 1 file changed, 121 insertions(+)
 create mode 100644 src/main/java/org/traccar/protocol/Xexun2ProtocolEncoder.java

(limited to 'src/main/java/org/traccar/protocol/Xexun2ProtocolEncoder.java')

diff --git a/src/main/java/org/traccar/protocol/Xexun2ProtocolEncoder.java b/src/main/java/org/traccar/protocol/Xexun2ProtocolEncoder.java
new file mode 100644
index 000000000..d85c6734b
--- /dev/null
+++ b/src/main/java/org/traccar/protocol/Xexun2ProtocolEncoder.java
@@ -0,0 +1,121 @@
+/*
+ * Copyright 2016 - 2022 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 org.traccar.BaseProtocolEncoder;
+import org.traccar.helper.DataConverter;
+import org.traccar.model.Command;
+import org.traccar.Protocol;
+
+import java.nio.ByteBuffer;
+import java.nio.charset.StandardCharsets;
+
+public class Xexun2ProtocolEncoder extends BaseProtocolEncoder {
+
+    public Xexun2ProtocolEncoder(Protocol protocol) {
+        super(protocol);
+    }
+
+    private static ByteBuf encodeFrame(ByteBuf buf) {
+        buf.clear();
+        if (buf.readableBytes() < 5) {
+            return null;
+        }
+
+        ByteBuf result = Unpooled.buffer();
+
+        result.writeBytes(buf.readBytes(2));
+
+        while (buf.readerIndex() < buf.capacity() - 2) {
+            int b = buf.readUnsignedByte();
+            if (b == 0xfa && buf.isReadable() && buf.getUnsignedByte(buf.readerIndex()) == 0xaf) {
+                buf.readUnsignedByte();
+                result.writeByte(0xfb);
+                result.writeByte(0xbf);
+                result.writeByte(0x01);
+            } else if (b == 0xfb && buf.isReadable() && buf.getUnsignedByte(buf.readerIndex()) == 0xbf) {
+                buf.readUnsignedByte();
+                result.writeByte(0xfb);
+                result.writeByte(0xbf);
+                result.writeByte(0x02);
+            } else {
+                result.writeByte(b);
+            }
+        }
+        result.writeBytes(buf.readBytes(2));
+
+        return result;
+    }
+
+    private static int checksum(byte[] data)
+    {
+        int sum = 0;
+        int len = data.length;
+        for (int j = 0; len > 1; len--) {
+            sum += data[j++] & 0xff;
+            if ((sum & 0x80000000) > 0) {
+                sum = (sum & 0xffff) + (sum >> 16);
+            }
+        }
+        if (len == 1) {
+            sum += data[data.length - 1] & 0xff;
+        }
+        while ((sum >> 16) > 0) {
+            sum = (sum & 0xffff) + sum >> 16;
+        }
+        sum = (sum == 0xffff) ? sum & 0xffff : (~sum) & 0xffff;
+        return sum;
+    }
+
+
+    private static ByteBuf encodeContent(String uniqueId, String content) {
+        ByteBuf buf = Unpooled.buffer();
+
+        byte[] message = content.getBytes();
+
+        buf.writeShort(0xFAAF);
+        buf.writeShort(0x0007);
+        buf.writeShort(0x0001);
+        buf.writeBytes(DataConverter.parseHex(uniqueId + "0"),0,8);
+        buf.writeShort(message.length);
+        buf.writeShort(checksum(message));
+        buf.writeBytes(message);
+        buf.writeShort(0xFAAF);
+
+        return encodeFrame(buf);
+    }
+
+    @Override
+    protected Object encodeCommand(Command command) {
+        String uniqueId = getUniqueId(command.getDeviceId());
+
+        switch (command.getType()) {
+            case Command.TYPE_CUSTOM:
+                return encodeContent(uniqueId, command.getString(Command.KEY_DATA));
+            case Command.TYPE_POSITION_PERIODIC:
+                return encodeContent(uniqueId, String.format("tracking_send=%1$d,%1$d", command.getInteger(Command.KEY_FREQUENCY)));
+            case Command.TYPE_POWER_OFF:
+                return encodeContent(uniqueId, "of=1");
+            case Command.TYPE_REBOOT_DEVICE:
+                return encodeContent(uniqueId, "reset");
+            default:
+                return null;
+        }
+    }
+
+}
-- 
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