package com.example.agvcontroller.protocol;
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import io.netty.buffer.ByteBuf;
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import io.netty.channel.ChannelHandlerContext;
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import io.netty.handler.codec.ByteToMessageDecoder;
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import io.netty.util.ReferenceCountUtil;
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import com.example.agvcontroller.socket.RadixTools;
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import java.net.InetSocketAddress;
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import java.util.List;
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/**
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* Created by vincent on 2019-04-10
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*/
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public class ProtocolDecoder extends ByteToMessageDecoder {
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private final int maxFrameLength;
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public ProtocolDecoder(int maxFrameLength){
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this.maxFrameLength = maxFrameLength;
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}
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@Override
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protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
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String ip = ((InetSocketAddress) ctx.channel().remoteAddress()).getAddress().getHostAddress();
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// log.info("ip:{} ===>> {}", ip, ByteBufUtil.hexDump(in).toUpperCase());
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int startMark = indexOfStartMark(in);
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if (startMark == -1){
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in.skipBytes(in.readableBytes());
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return;
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}
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if (in.readableBytes() > maxFrameLength) {
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in.skipBytes(in.readableBytes());
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return;
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}
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// 去除无用前缀报文
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if (startMark != 0){
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in.readerIndex(startMark);
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in.discardReadBytes();
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}
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// 粘包处理
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in.markReaderIndex();
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in.readerIndex(PackagePart.CONTENT_LENGTH.getStartIndex());
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int pacTotalLen = PackagePart.START_SYMBOL.getLen()
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+ PackagePart.CONTENT_LENGTH.getLen()
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+ in.readShortLE()
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+ PackagePart.VALIDE_CODE.getLen()
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;
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in.resetReaderIndex();
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ByteBuf byteBuf = in.readSlice(pacTotalLen);
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// 生成和初始化消息包装类
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AgvPackage pac = AgvPackage.valueOfEmpty();
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pac.setSourceBuff(byteBuf);
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// 解析
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out.add(analyzeProtocol(pac));
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// byteBuf.resetReaderIndex(); // tip: 如果 ridx == widx，则 refCnt = 0
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in.resetReaderIndex();
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in.skipBytes(pacTotalLen); // tip: This method will be called till either the input has nothing to read，无语！
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ReferenceCountUtil.retain(in); // 解码器自动释放 refCnt - 1
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}
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public AgvPackage analyzeProtocol(AgvPackage pac){
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ByteBuf byteBuf = pac.getSourceBuff();
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PacHeader pacHeader = pac.getHeader();
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// 唯一标识码
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byteBuf.readerIndex(PackagePart.UNIQUENO.getStartIndex());
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byte[] bytes = new byte[PackagePart.UNIQUENO.getLen()];
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byteBuf.readBytes(bytes);
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Utils.reverse(bytes);
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String uniqueno = String.valueOf(RadixTools.bytesToInt(bytes));
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if (!Cools.isEmpty(uniqueno)) {
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pacHeader.setUniqueNo(uniqueno);
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byteBuf.resetReaderIndex();
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} else {
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return pac.setErrorPac(Boolean.TRUE).setPacErrorType(PacErrorType.PAC_ANALYZE_ERROR);
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}
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// 获取标识符
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byte startSymbol = byteBuf.readByte();
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DirectionType direction = null;
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if ((0xEE&0xFF) == (startSymbol&0xFF)) {
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pacHeader.setStartSymbol(startSymbol);
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direction = DirectionType.DOWN;
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} else if ((0xAA&0xFF) == (startSymbol&0xFF)) {
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pacHeader.setStartSymbol(startSymbol);
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direction = DirectionType.UP;
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} else {
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return pac.setErrorPac(Boolean.TRUE).setPacErrorType(PacErrorType.PAC_ANALYZE_ERROR);
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}
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// 获取协议体长度
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int contentLength = byteBuf.readShortLE();
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if (contentLength >= 0) {
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pacHeader.setContentLength(contentLength);
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} else {
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return pac.setErrorPac(Boolean.TRUE).setPacErrorType(PacErrorType.PAC_ANALYZE_ERROR);
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}
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// skip uniqueNo
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byteBuf.readerIndex(byteBuf.readerIndex() + PackagePart.UNIQUENO.getLen());
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// 获取时间戳
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byteBuf.readerIndex(PackagePart.TIMESTAMP.getStartIndex());
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int timestamp = byteBuf.readIntLE();
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if (timestamp > 0) {
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pacHeader.setTimestamp(timestamp);
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} else {
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return pac.setErrorPac(Boolean.TRUE).setPacErrorType(PacErrorType.PAC_ANALYZE_ERROR);
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}
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// 获取命令标识
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int commandByte = byteBuf.readByte() & 0xFF;
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ProtocolType protocolType = ProtocolType.getByCode(commandByte, direction);
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if (null != protocolType) {
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pacHeader.setProtocolType(protocolType);
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} else {
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return pac.setErrorPac(Boolean.TRUE).setPacErrorType(PacErrorType.PAC_ANALYZE_ERROR);
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}
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// 获取协议体
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if (contentLength > 0) {
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ByteBuf body = byteBuf.readSlice(pac.getHeader().getContentLength() - (
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+ PackagePart.UNIQUENO.getLen()
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+ PackagePart.TIMESTAMP.getLen()
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+ PackagePart.COMMAND_MARK.getLen()
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));
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if (null != body && body.readableBytes() >= 0) {
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pac.getBody().setContent(body);
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} else {
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return pac.setErrorPac(Boolean.TRUE).setPacErrorType(PacErrorType.PAC_ANALYZE_ERROR);
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}
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}
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// 校验码
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if(byteBuf.readableBytes() == 2) {
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pac.setValidCode(byteBuf.readUnsignedShortLE());
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} else {
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return pac.setErrorPac(Boolean.TRUE).setPacErrorType(PacErrorType.PAC_ANALYZE_ERROR);
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}
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return pac;
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}
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// 获取标识位下标
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private int indexOfStartMark(ByteBuf inputBuffer){
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int length = inputBuffer.writerIndex();
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// 报文长度至少大于2
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if (length < 2) {
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return -1;
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}
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int readerIndex = inputBuffer.readerIndex();
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for(int i = readerIndex; i < length - 1; i ++) {
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byte b1 = inputBuffer.getByte(i);
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if ((0xEE&0xFF) == (b1&0xFF) || (0xAA&0xFF) == (b1&0xFF)) {
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return i;
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}
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}
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return -1;
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}
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}
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