VT200 custom frame decoder

2 files changed, 52 insertions, 2 deletions

diff --git a/src/org/traccar/protocol/Vt200FrameDecoder.java b/src/org/traccar/protocol/Vt200FrameDecoder.java
new file mode 100644
index 000000000..adde12118
--- /dev/null
+++ b/src/org/traccar/protocol/Vt200FrameDecoder.java
@@ -0,0 +1,51 @@
+/*
+ * Copyright 2017 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.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.FrameDecoder;
+
+public class Vt200FrameDecoder extends FrameDecoder {
+
+    @Override
+    protected Object decode(
+            ChannelHandlerContext ctx, Channel channel, ChannelBuffer buf) throws Exception {
+
+        int endIndex = buf.indexOf(buf.readerIndex(), buf.writerIndex(), (byte) ')') + 1;
+        if (endIndex > 0) {
+
+            ChannelBuffer frame = ChannelBuffers.dynamicBuffer();
+
+            while (buf.readerIndex() < endIndex) {
+                int b = buf.readByte();
+                if (b == '=') {
+                    frame.writeByte(buf.readByte() ^ '=');
+                } else {
+                    frame.writeByte(b);
+                }
+            }
+
+            return frame;
+
+        }
+
+        return null;
+    }
+
+}
diff --git a/src/org/traccar/protocol/Vt200Protocol.java b/src/org/traccar/protocol/Vt200Protocol.java
index 4a8587b21..59c61cb61 100644
--- a/src/org/traccar/protocol/Vt200Protocol.java
+++ b/src/org/traccar/protocol/Vt200Protocol.java
@@ -17,7 +17,6 @@ package org.traccar.protocol;
 
 import org.jboss.netty.bootstrap.ServerBootstrap;
 import org.jboss.netty.channel.ChannelPipeline;
-import org.jboss.netty.handler.codec.frame.LengthFieldBasedFrameDecoder;
 import org.traccar.BaseProtocol;
 import org.traccar.TrackerServer;
 
@@ -34,7 +33,7 @@ public class Vt200Protocol extends BaseProtocol {
         serverList.add(new TrackerServer(new ServerBootstrap(), getName()) {
             @Override
             protected void addSpecificHandlers(ChannelPipeline pipeline) {
-                pipeline.addLast("frameDecoder", new LengthFieldBasedFrameDecoder(1024, 1 + 6 + 2, 2, 2, 0));
+                pipeline.addLast("frameDecoder", new Vt200FrameDecoder());
                 pipeline.addLast("objectDecoder", new Vt200ProtocolDecoder(Vt200Protocol.this));
             }
         });