From 6a6adc4f33d38ee964494d01100eaa127adbf356 Mon Sep 17 00:00:00 2001
From: Anton Tananaev <anton.tananaev@gmail.com>
Date: Wed, 1 May 2013 23:38:28 +1200
Subject: Support intellitrac sync message (fix #227)

---
 .../traccar/protocol/IntellitracFrameDecoder.java  | 58 ++++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 src/org/traccar/protocol/IntellitracFrameDecoder.java

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

diff --git a/src/org/traccar/protocol/IntellitracFrameDecoder.java b/src/org/traccar/protocol/IntellitracFrameDecoder.java
new file mode 100644
index 000000000..461186310
--- /dev/null
+++ b/src/org/traccar/protocol/IntellitracFrameDecoder.java
@@ -0,0 +1,58 @@
+/*
+ * Copyright 2013 Anton Tananaev (anton.tananaev@gmail.com)
+ *
+ * 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.jboss.netty.buffer.ChannelBuffer;
+import org.jboss.netty.buffer.ChannelBuffers;
+import org.jboss.netty.channel.Channel;
+import org.jboss.netty.channel.ChannelHandlerContext;
+import org.jboss.netty.handler.codec.frame.DelimiterBasedFrameDecoder;
+
+public class IntellitracFrameDecoder extends DelimiterBasedFrameDecoder {
+
+    private static final int MESSAGE_MINIMUM_LENGTH = 0;
+    
+    private static final byte delimiter[] = { (byte) '\r', (byte) '\n' };
+    
+    public IntellitracFrameDecoder(int maxFrameLength) {
+        super(maxFrameLength, ChannelBuffers.wrappedBuffer(delimiter));
+    }
+    
+    // example of sync header: 0xFA 0xF8 0x1B 0x01 0x81 0x60 0x33 0x3C
+    
+    @Override
+    protected Object decode(
+            ChannelHandlerContext ctx,
+            Channel channel,
+            ChannelBuffer buf) throws Exception {
+        
+        // Check minimum length
+        if (buf.readableBytes() < MESSAGE_MINIMUM_LENGTH) {
+            return null;
+        }
+        
+        // Check for sync packet
+        if (buf.getUnsignedShort(buf.readerIndex()) == 0xFAF8) {
+            ChannelBuffer syncMessage = buf.readBytes(8);
+            if (channel != null) {
+                channel.write(syncMessage);
+            }
+        }
+
+        return super.decode(ctx, channel, buf);
+    }
+
+}
-- 
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