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/*
* Copyright 2012 - 2013 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 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;
import org.traccar.helper.ChannelBufferTools;
public class XexunFrameDecoder extends FrameDecoder {
@Override
protected Object decode(
ChannelHandlerContext ctx,
Channel channel,
ChannelBuffer buf) throws Exception {
// Check minimum length
int length = buf.readableBytes();
if (length < 80) {
return null;
}
// Find start
Integer beginIndex = ChannelBufferTools.find(buf, 0, length, "GPRMC");
if (beginIndex == null) {
beginIndex = ChannelBufferTools.find(buf, 0, length, "GNRMC");
if (beginIndex == null) {
return null;
}
}
// Find identifier
Integer idIndex = ChannelBufferTools.find(buf, beginIndex, length, "imei:");
if (idIndex == null) {
return null;
}
// Find end
Integer endIndex = ChannelBufferTools.find(buf, idIndex, length, ",");
if (endIndex == null) {
return null;
}
// Read buffer
buf.skipBytes(beginIndex);
ChannelBuffer frame = buf.readBytes(endIndex - beginIndex + 1);
return frame;
}
}
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