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/*
* Copyright 2017 Valerii Vyshniak (val@val.one)
* Copyright 2017 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 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 Tk103FrameDecoder extends FrameDecoder {
@Override
protected Object decode(
ChannelHandlerContext ctx,
Channel channel,
ChannelBuffer buf) throws Exception {
if (buf.readableBytes() < 2) {
return null;
}
int frameStartIndex = buf.indexOf(buf.readerIndex(), buf.writerIndex(), (byte) '(');
if (frameStartIndex == -1) {
buf.clear();
return null;
}
frameStartIndex++;
int frameEndIndex, freeTextSymbolCounter;
for (frameEndIndex = frameStartIndex, freeTextSymbolCounter = 0;; frameEndIndex++) {
int freeTextIndex = frameEndIndex;
frameEndIndex = buf.indexOf(frameEndIndex, buf.writerIndex(), (byte) ')');
if (frameEndIndex == -1) {
break;
}
for (;; freeTextIndex++, freeTextSymbolCounter++) {
freeTextIndex = buf.indexOf(freeTextIndex, frameEndIndex, (byte) '$');
if (freeTextIndex == -1 || freeTextIndex >= frameEndIndex) {
break;
}
}
if (freeTextSymbolCounter % 2 == 0) {
break;
}
}
if (frameEndIndex == -1) {
while (buf.readableBytes() > 1024) {
int discardUntilIndex = buf.indexOf(buf.readerIndex() + 1, buf.writerIndex(), (byte) '(');
if (discardUntilIndex == -1) {
buf.clear();
} else {
buf.readerIndex(discardUntilIndex);
}
}
return null;
}
buf.readerIndex(frameStartIndex);
ChannelBuffer result = buf.readBytes(frameEndIndex - frameStartIndex);
buf.readerIndex(buf.readerIndex() + 1);
return result;
}
}
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