From bec490817a2251dc37f727f3a755a20411761993 Mon Sep 17 00:00:00 2001
From: Anton Tananaev <anton.tananaev@gmail.com>
Date: Wed, 24 Apr 2019 21:37:47 -0700
Subject: Implement Suntech frame decoder

---
 .../org/traccar/protocol/SuntechFrameDecoder.java  | 47 ++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 src/main/java/org/traccar/protocol/SuntechFrameDecoder.java

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

diff --git a/src/main/java/org/traccar/protocol/SuntechFrameDecoder.java b/src/main/java/org/traccar/protocol/SuntechFrameDecoder.java
new file mode 100644
index 000000000..de8de17f0
--- /dev/null
+++ b/src/main/java/org/traccar/protocol/SuntechFrameDecoder.java
@@ -0,0 +1,47 @@
+/*
+ * Copyright 2019 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 io.netty.buffer.ByteBuf;
+import io.netty.channel.Channel;
+import io.netty.channel.ChannelHandlerContext;
+import org.traccar.BaseFrameDecoder;
+
+public class SuntechFrameDecoder extends BaseFrameDecoder {
+
+    private ByteBuf readFrame(ByteBuf buf, int delimiterIndex) {
+        ByteBuf frame = buf.readRetainedSlice(delimiterIndex - buf.readerIndex());
+        buf.skipBytes(1); // delimiter
+        return frame;
+    }
+
+    @Override
+    protected Object decode(
+            ChannelHandlerContext ctx, Channel channel, ByteBuf buf) throws Exception {
+
+        int delimiterIndex = buf.indexOf(buf.readerIndex(), buf.writerIndex(), (byte) '\r');
+        while (delimiterIndex > 0) {
+            if (delimiterIndex + 1 < buf.writerIndex() && buf.getByte(delimiterIndex + 1) == '\n') {
+                delimiterIndex = buf.indexOf(delimiterIndex + 1, buf.writerIndex(), (byte) '\r');
+            } else {
+                return readFrame(buf, delimiterIndex);
+            }
+        }
+
+        return null;
+    }
+
+}
-- 
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