1 files changed, 65 insertions, 0 deletions
diff --git a/src/org/traccar/protocol/GranitFrameDecoder.java b/src/org/traccar/protocol/GranitFrameDecoder.java
new file mode 100644
index 000000000..b0581c96c
--- /dev/null
+++ b/src/org/traccar/protocol/GranitFrameDecoder.java
@@ -0,0 +1,65 @@
+/*
+ * Copyright 2016 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 java.nio.charset.StandardCharsets;
+
+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;
+import org.traccar.helper.StringFinder;
+
+public class GranitFrameDecoder extends FrameDecoder {
+
+    private static final int HEADER_LENGTH = 6;
+    private static final int CHECKSUM_LENGTH = 3;
+    private static final int SHORT_LENGTH = 2;
+
+    @Override
+    protected Object decode(
+            ChannelHandlerContext ctx, Channel channel, ChannelBuffer buf) throws Exception {
+
+        if (buf.readableBytes() > HEADER_LENGTH + SHORT_LENGTH) {
+            ChannelBuffer frame = ChannelBuffers.dynamicBuffer();
+            buf.getBytes(buf.readerIndex(), frame, HEADER_LENGTH);
+            String headerString = frame.toString(StandardCharsets.US_ASCII);
+            if (headerString.equals("+RRCB~") || headerString.equals("+DDAT~")) {
+                int length = buf.getUnsignedShort(buf.readerIndex() + HEADER_LENGTH);
+                if (buf.readableBytes() >= HEADER_LENGTH + SHORT_LENGTH + length + CHECKSUM_LENGTH) {
+                    frame = buf.readBytes(HEADER_LENGTH + SHORT_LENGTH + length + CHECKSUM_LENGTH);
+                    if (buf.readableBytes() > 2) {
+                        buf.skipBytes(2); //skip \r\n
+                    }
+                    return frame;
+                } else {
+                    return null; //damaged packet
+                }
+            }
+        }
+
+        int index = buf.indexOf(buf.readerIndex(), buf.writerIndex(), new StringFinder("\r\n"));
+        if (index != -1) {
+            ChannelBuffer frame = buf.readBytes(index - buf.readerIndex());
+            buf.skipBytes(2);
+            return frame;
+        }
+
+        return null;
+    }
+
+}