Fix jt600 frame decoder (fix #290)

2 files changed, 16 insertions, 28 deletions

diff --git a/src/org/traccar/protocol/Jt600FrameDecoder.java b/src/org/traccar/protocol/Jt600FrameDecoder.java
index 2e2fd228b..d2fbc4ca8 100644
--- a/src/org/traccar/protocol/Jt600FrameDecoder.java
+++ b/src/org/traccar/protocol/Jt600FrameDecoder.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012 Anton Tananaev (anton.tananaev@gmail.com)
+ * Copyright 2012 - 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.
@@ -24,25 +24,30 @@ import org.traccar.helper.ChannelBufferTools;
 
 public class Jt600FrameDecoder extends FrameDecoder {
 
-    private static int MESSAGE_LENGTH = 37;
-
+    @Override
     protected Object decode(
             ChannelHandlerContext ctx,
             Channel channel,
             ChannelBuffer buf) throws Exception {
 
+        // Check minimum length
+        int available = buf.readableBytes();
+        if (available < 10) {
+            return null;
+        }
+        
         // Message identifier
-        char first = (char) buf.getByte(0);
-        int length = buf.readableBytes();
+        char first = (char) buf.getByte(buf.readerIndex());
         
         if (first == '$') {
             // Check length
-            if (length >= MESSAGE_LENGTH) {
-                return buf.readBytes(MESSAGE_LENGTH);
+            int length = buf.getUnsignedShort(buf.readerIndex() + 7) + 10;
+            if (length >= available) {
+                return buf.readBytes(length);
             }
         } else if (first == '(') {
             // Find ending
-            Integer endIndex = ChannelBufferTools.find(buf, 0, length, ")");
+            Integer endIndex = ChannelBufferTools.find(buf, buf.readerIndex(), available, ")");
             if (endIndex != null) {
                 return buf.readBytes(endIndex + 1);
             }
diff --git a/src/org/traccar/protocol/Jt600ProtocolDecoder.java b/src/org/traccar/protocol/Jt600ProtocolDecoder.java
index 6a8f9da52..86711a644 100644
--- a/src/org/traccar/protocol/Jt600ProtocolDecoder.java
+++ b/src/org/traccar/protocol/Jt600ProtocolDecoder.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012 Anton Tananaev (anton.tananaev@gmail.com)
+ * Copyright 2012 - 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.
@@ -29,21 +29,12 @@ import org.traccar.helper.ChannelBufferTools;
 import org.traccar.helper.Log;
 import org.traccar.model.Position;
 
-/**
- * JT600 protocol decoder
- */
 public class Jt600ProtocolDecoder extends BaseProtocolDecoder {
 
-    /**
-     * Initialize
-     */
     public Jt600ProtocolDecoder(ServerManager serverManager) {
         super(serverManager);
     }
 
-    /**
-     * Decode regular message
-     */
     private Position decodeNormalMessage(ChannelBuffer buf) throws Exception {
 
         Position position = new Position();
@@ -56,7 +47,7 @@ public class Jt600ProtocolDecoder extends BaseProtocolDecoder {
             position.setDeviceId(getDataManager().getDeviceByImei(id).getId());
         } catch(Exception error) {
             Log.warning("Unknown device - " + id);
-            return null;
+            //return null;
         }
 
         buf.readByte(); // protocol version + data type
@@ -122,9 +113,6 @@ public class Jt600ProtocolDecoder extends BaseProtocolDecoder {
         return position;
     }
 
-    /**
-     * Alert message pattern
-     */
     static private Pattern pattern = Pattern.compile(
             "\\(" +
             "([\\d]+)," +                // Id
@@ -144,9 +132,6 @@ public class Jt600ProtocolDecoder extends BaseProtocolDecoder {
             "(\\d+)," +                  // Alert Type
             ".*\\)");
 
-    /**
-     * Decode alert message
-     */
     private Position decodeAlertMessage(ChannelBuffer buf) throws Exception {
 
         String message = buf.toString(Charset.defaultCharset());
@@ -208,9 +193,7 @@ public class Jt600ProtocolDecoder extends BaseProtocolDecoder {
         return position;
     }
 
-    /**
-     * Decode message
-     */
+    @Override
     protected Object decode(
             ChannelHandlerContext ctx, Channel channel, Object msg)
             throws Exception {