From 59416923dcb3a756eaf532cc4259f2f6625c0762 Mon Sep 17 00:00:00 2001
From: Anton Tananaev <anton.tananaev@gmail.com>
Date: Sun, 31 Mar 2019 22:35:39 -0700
Subject: Convert project to gradle

---
 .../java/org/traccar/protocol/BceFrameDecoder.java | 59 ++++++++++++++++++++++
 1 file changed, 59 insertions(+)
 create mode 100644 src/main/java/org/traccar/protocol/BceFrameDecoder.java

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

diff --git a/src/main/java/org/traccar/protocol/BceFrameDecoder.java b/src/main/java/org/traccar/protocol/BceFrameDecoder.java
new file mode 100644
index 000000000..381a97696
--- /dev/null
+++ b/src/main/java/org/traccar/protocol/BceFrameDecoder.java
@@ -0,0 +1,59 @@
+/*
+ * Copyright 2015 - 2018 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 BceFrameDecoder extends BaseFrameDecoder {
+
+    private static final int HANDSHAKE_LENGTH = 7; // "#BCE#\r\n"
+
+    private boolean header = true;
+
+    private static byte checksum(ByteBuf buf, int end) {
+        byte result = 0;
+        for (int i = 0; i < end; i++) {
+            result += buf.getByte(buf.readerIndex() + i);
+        }
+        return result;
+    }
+
+    @Override
+    protected Object decode(
+            ChannelHandlerContext ctx, Channel channel, ByteBuf buf) throws Exception {
+
+        if (header && buf.readableBytes() >= HANDSHAKE_LENGTH) {
+            buf.skipBytes(HANDSHAKE_LENGTH);
+            header = false;
+        }
+
+        int end = 8; // IMEI
+
+        while (buf.readableBytes() >= end + 2 + 1 + 1 + 1) {
+            end += buf.getUnsignedShortLE(buf.readerIndex() + end) + 2;
+
+            if (buf.readableBytes() > end && checksum(buf, end) == buf.getByte(buf.readerIndex() + end)) {
+                return buf.readRetainedSlice(end + 1);
+            }
+        }
+
+        return null;
+    }
+
+}
-- 
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