/* * Copyright 2022 Stefan Clark (stefan@stefanclark.co.uk) * * 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.ChannelHandlerContext; import io.netty.handler.codec.MessageToByteEncoder; public class Xexun2FrameEncoder extends MessageToByteEncoder<ByteBuf> { @Override protected void encode(ChannelHandlerContext ctx, ByteBuf msg, ByteBuf out) { out.writeBytes(msg.readBytes(2)); while (msg.readableBytes() > 2) { int b = msg.readUnsignedByte(); if (b == 0xfa && msg.isReadable() && msg.getUnsignedByte(msg.readerIndex()) == 0xaf) { msg.readUnsignedByte(); out.writeByte(0xfb); out.writeByte(0xbf); out.writeByte(0x01); } else if (b == 0xfb && msg.isReadable() && msg.getUnsignedByte(msg.readerIndex()) == 0xbf) { msg.readUnsignedByte(); out.writeByte(0xfb); out.writeByte(0xbf); out.writeByte(0x02); } else { out.writeByte(b); } } out.writeBytes(msg.readBytes(2)); } }