1 files changed, 70 insertions, 0 deletions
diff --git a/src/main/java/org/traccar/protocol/UlbotechFrameDecoder.java b/src/main/java/org/traccar/protocol/UlbotechFrameDecoder.java
new file mode 100644
index 000000000..f141dc9b7
--- /dev/null
+++ b/src/main/java/org/traccar/protocol/UlbotechFrameDecoder.java
@@ -0,0 +1,70 @@
+/*
+ * Copyright 2014 - 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.traccar.BaseFrameDecoder;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelHandlerContext;
+
+public class UlbotechFrameDecoder extends BaseFrameDecoder {
+
+    @Override
+    protected Object decode(
+            ChannelHandlerContext ctx, Channel channel, ByteBuf buf) throws Exception {
+
+        if (buf.readableBytes() < 2) {
+            return null;
+        }
+
+        if (buf.getUnsignedByte(buf.readerIndex()) == 0xF8) {
+
+            int index = buf.indexOf(buf.readerIndex() + 1, buf.writerIndex(), (byte) 0xF8);
+            if (index != -1) {
+                ByteBuf result = Unpooled.buffer(index + 1 - buf.readerIndex());
+
+                while (buf.readerIndex() <= index) {
+                    int b = buf.readUnsignedByte();
+                    if (b == 0xF7) {
+                        int ext = buf.readUnsignedByte();
+                        if (ext == 0x00) {
+                            result.writeByte(0xF7);
+                        } else if (ext == 0x0F) {
+                            result.writeByte(0xF8);
+                        }
+                    } else {
+                        result.writeByte(b);
+                    }
+                }
+
+                return result;
+            }
+
+        } else {
+
+            int index = buf.indexOf(buf.readerIndex(), buf.writerIndex(), (byte) '#');
+            if (index != -1) {
+                return buf.readRetainedSlice(index + 1 - buf.readerIndex());
+            }
+
+        }
+
+        return null;
+    }
+
+}