1 files changed, 74 insertions, 0 deletions
diff --git a/src/org/traccar/protocol/Arnavi4FrameDecoder.java b/src/org/traccar/protocol/Arnavi4FrameDecoder.java
new file mode 100644
index 000000000..b13f3fd7d
--- /dev/null
+++ b/src/org/traccar/protocol/Arnavi4FrameDecoder.java
@@ -0,0 +1,74 @@
+/*
+ * Copyright 2017 Ivan Muratov (binakot@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.channel.Channel;
+import org.jboss.netty.channel.ChannelHandlerContext;
+import org.jboss.netty.handler.codec.frame.FrameDecoder;
+
+public class Arnavi4FrameDecoder extends FrameDecoder {
+
+    private static final int MIN_LENGTH = 4;
+    private static final int HEADER_LENGTH = 10;
+    private static final int PACKET_WRAPPER_LENGTH = 8;
+    private static final int COMMAND_ANSWER_PACKET_LENGTH = 4;
+    private static final int COMMAND_ANSWER_PARCEL_NUMBER = 0xfd;
+    private static final byte PACKAGE_END_SIGN = 0x5d;
+
+    private boolean firstPacket = true;
+
+    @Override
+    protected Object decode(
+            ChannelHandlerContext ctx, Channel channel, ChannelBuffer buf) throws Exception {
+
+        if (buf.readableBytes() < MIN_LENGTH) {
+            return null;
+        }
+
+        int length;
+        if (firstPacket) {
+            firstPacket = false;
+            length = HEADER_LENGTH;
+        } else {
+            int index = buf.getUnsignedByte(1); // parcel number
+            if (index == COMMAND_ANSWER_PARCEL_NUMBER) {
+                length = COMMAND_ANSWER_PACKET_LENGTH;
+            } else {
+                int pos = 2; // start sign + parcel number
+                while (pos + PACKET_WRAPPER_LENGTH < buf.readableBytes()
+                        && buf.getByte(pos) != PACKAGE_END_SIGN) {
+
+                    int dataLength = buf.getUnsignedShort(pos + 1);
+                    pos += PACKET_WRAPPER_LENGTH + dataLength; // packet type + data length + unixtime + data + crc
+                }
+
+                if (buf.getByte(pos) != PACKAGE_END_SIGN) { // end sign
+                    return null;
+                }
+
+                length = pos + 1;
+            }
+        }
+
+        if (buf.readableBytes() >= length) {
+            return buf.readBytes(length);
+        }
+
+        return null;
+    }
+
+}