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/*
* 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;
import org.traccar.helper.BufferUtil;
import java.nio.charset.StandardCharsets;
public class MegastekFrameDecoder extends BaseFrameDecoder {
@Override
protected Object decode(
ChannelHandlerContext ctx, Channel channel, ByteBuf buf) throws Exception {
if (buf.readableBytes() < 10) {
return null;
}
if (Character.isDigit(buf.getByte(buf.readerIndex()))) {
int length = 4 + Integer.parseInt(buf.toString(buf.readerIndex(), 4, StandardCharsets.US_ASCII));
if (buf.readableBytes() >= length) {
return buf.readRetainedSlice(length);
}
} else {
while (buf.getByte(buf.readerIndex()) == '\r' || buf.getByte(buf.readerIndex()) == '\n') {
buf.skipBytes(1);
}
int delimiter = BufferUtil.indexOf("\r\n", buf);
if (delimiter == -1) {
delimiter = buf.indexOf(buf.readerIndex(), buf.writerIndex(), (byte) '!');
}
if (delimiter == -1) {
delimiter = buf.indexOf(buf.readerIndex(), buf.writerIndex(), (byte) '\n');
}
if (delimiter != -1) {
ByteBuf result = buf.readRetainedSlice(delimiter - buf.readerIndex());
buf.skipBytes(1);
return result;
}
}
return null;
}
}
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