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Diffstat (limited to 'src/org/traccar/protocol/xexun/XexunFrameDecoder.java')
-rw-r--r--src/org/traccar/protocol/xexun/XexunFrameDecoder.java92
1 files changed, 92 insertions, 0 deletions
diff --git a/src/org/traccar/protocol/xexun/XexunFrameDecoder.java b/src/org/traccar/protocol/xexun/XexunFrameDecoder.java
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index 000000000..839e5b3ec
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+++ b/src/org/traccar/protocol/xexun/XexunFrameDecoder.java
@@ -0,0 +1,92 @@
+/*
+ * Copyright 2010 Anton Tananaev (anton@tananaev.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 net.sourceforge.opentracking.protocol.xexun;
+
+import org.jboss.netty.handler.codec.frame.FrameDecoder;
+import org.jboss.netty.channel.Channel;
+import org.jboss.netty.channel.ChannelHandlerContext;
+import org.jboss.netty.buffer.ChannelBuffer;
+
+public class XexunFrameDecoder extends FrameDecoder {
+
+ /**
+ * Find string in network buffer
+ */
+ private static Integer find(
+ ChannelBuffer buf,
+ Integer start,
+ Integer length,
+ String subString) {
+
+ int index = start;
+ boolean match;
+
+ for (; index < length; index++) {
+ match = true;
+
+ for (int i = 0; i < subString.length(); i++) {
+ char c = (char) buf.getByte(index + i);
+ if (c != subString.charAt(i)) {
+ match = false;
+ break;
+ }
+ }
+
+ if (match) {
+ return index;
+ }
+ }
+
+ return null;
+ }
+
+ protected Object decode(
+ ChannelHandlerContext ctx,
+ Channel channel,
+ ChannelBuffer buf) throws Exception {
+
+ // Check minimum length
+ int length = buf.readableBytes();
+ if (length < 100) {
+ return null;
+ }
+
+ // Find start
+ Integer beginIndex = find(buf, 0, length, "GPRMC");
+ if (beginIndex == null) {
+ return null;
+ }
+
+ // Find identifier
+ Integer idIndex = find(buf, beginIndex, length, "imei:");
+ if (idIndex == null) {
+ return null;
+ }
+
+ // Find end
+ Integer endIndex = find(buf, idIndex, length, ",");
+ if (endIndex == null) {
+ return null;
+ }
+
+ // Read buffer
+ buf.skipBytes(beginIndex);
+ ChannelBuffer frame = buf.readBytes(endIndex - beginIndex + 1);
+
+ return frame;
+ }
+
+}