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/*
* Copyright 2017 - 2020 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 AtrackFrameDecoder extends BaseFrameDecoder {
private static final int KEEPALIVE_LENGTH = 12;
@Override
protected Object decode(
ChannelHandlerContext ctx, Channel channel, ByteBuf buf) throws Exception {
if (buf.readableBytes() >= 2) {
if (buf.getUnsignedShort(buf.readerIndex()) == 0xfe02) {
if (buf.readableBytes() >= KEEPALIVE_LENGTH) {
return buf.readRetainedSlice(KEEPALIVE_LENGTH);
}
} else if (buf.getUnsignedByte(buf.readerIndex()) == 0x40 && buf.getByte(buf.readerIndex() + 2) != ',') {
if (buf.readableBytes() > 6) {
int length = buf.getUnsignedShort(buf.readerIndex() + 4) + 4 + 2;
if (buf.readableBytes() >= length) {
return buf.readRetainedSlice(length);
}
}
} else {
int lengthStart = buf.indexOf(buf.readerIndex() + 3, buf.writerIndex(), (byte) ',') + 1;
if (lengthStart > 0) {
int lengthEnd = buf.indexOf(lengthStart, buf.writerIndex(), (byte) ',');
if (lengthEnd > 0) {
int length = lengthEnd + Integer.parseInt(buf.toString(
lengthStart, lengthEnd - lengthStart, StandardCharsets.US_ASCII));
if (buf.readableBytes() > length && buf.getByte(buf.readerIndex() + length) == '\n') {
length += 1;
}
if (buf.readableBytes() >= length) {
return buf.readRetainedSlice(length);
}
}
} else {
int endIndex = BufferUtil.indexOf("\r\n", buf);
if (endIndex > 0) {
return buf.readRetainedSlice(endIndex - buf.readerIndex() + 2);
}
}
}
}
return null;
}
}
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