Java tutorial
/* * MIT License * * Copyright (c) 2016 Asynchronous Game Query Library * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in all * copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NON INFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ package com.ibasco.agql.protocols.valve.source.query; import com.ibasco.agql.core.AbstractPacketBuilder; import com.ibasco.agql.core.utils.ByteUtils; import com.ibasco.agql.protocols.valve.source.query.enums.SourceGameResponse; import com.ibasco.agql.protocols.valve.source.query.packets.response.SourceChallengeResponsePacket; import com.ibasco.agql.protocols.valve.source.query.packets.response.SourceInfoResponsePacket; import com.ibasco.agql.protocols.valve.source.query.packets.response.SourcePlayerResponsePacket; import com.ibasco.agql.protocols.valve.source.query.packets.response.SourceRulesResponsePacket; import io.netty.buffer.ByteBuf; import io.netty.buffer.ByteBufAllocator; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * <p>Responsible for encoding and decoding of source packets</p> * * Created by raffy on 9/16/2016. */ public class SourcePacketBuilder extends AbstractPacketBuilder<SourceServerPacket> { private static final Logger log = LoggerFactory.getLogger(SourcePacketBuilder.class); public SourcePacketBuilder(ByteBufAllocator alloc) { super(alloc); } public static <T extends SourceServerPacket> SourceServerPacket createResponsePacketFromHeader(byte header) { SourceGameResponse res = SourceGameResponse.get(header); if (res == null) { log.debug("Did not find a matching response class for header : {}", header); return null; } switch (res) { case CHALLENGE: return new SourceChallengeResponsePacket(); case INFO: return new SourceInfoResponsePacket(); case PLAYER: return new SourcePlayerResponsePacket(); case RULES: return new SourceRulesResponsePacket(); default: break; } return null; } @Override public <T extends SourceServerPacket> T construct(ByteBuf data) { //Mark Index data.markReaderIndex(); try { //Reset the index data.readerIndex(0); //Verify size if (data.readableBytes() < 5) throw new IllegalStateException( "Cannot continue processing buffer with less than or equal to 4 bytes"); //Read protocol header int protocolHeader = data.readIntLE(); //Check if this is a split packet if (protocolHeader == 0xFFFFFFFE) throw new IllegalStateException("Cannot construct a response from a partial/split packet."); //Verify that we have a valid header if (protocolHeader != 0xFFFFFFFF) throw new IllegalStateException("Protocol header not supported."); //Read packet header byte packetHeader = data.readByte(); //Read payload byte[] payload = new byte[data.readableBytes()]; data.readBytes(payload); //Verify if packet header is valid SourceServerPacket packet = createResponsePacketFromHeader(packetHeader); //If packet is empty, means the supplied packet header is not supported if (packet == null) return null; packet.setProtocolHeader(ByteUtils.byteArrayFromInteger(protocolHeader)); packet.setHeader(packetHeader); packet.setPayload(payload); return (T) packet; } finally { data.resetReaderIndex(); } } /** * Convert a source packet instance to it's byte representation * * @param packet The {@link SourceServerPacket} to convert * * @return Returns the deconstructed packet in byte array form */ @Override public byte[] deconstruct(SourceServerPacket packet) { if (packet == null) throw new IllegalArgumentException("Invalid packet specified in the arguments."); byte[] payload = packet.getPayload(); byte[] protocolHeader = packet.getProtocolHeader(); byte[] packetHeader = packet.getPacketHeader(); int payloadSize = payload != null ? payload.length : 0; int protocolHeaderSize = protocolHeader != null ? protocolHeader.length : 0; int packetHeaderSize = packetHeader != null ? packetHeader.length : 0; int packetSize = protocolHeaderSize + packetHeaderSize + payloadSize; //Allocate our buffer final ByteBuf buf = createBuffer(packetSize); byte[] data; try { //Include Protocol Header if available if (protocolHeaderSize > 0) buf.writeBytes(protocolHeader); //Include Packet Header if (packetHeaderSize > 0) buf.writeBytes(packetHeader); //Include Payload (if available) if (payloadSize > 0) buf.writeBytes(payload); //Store the buffer into a byte array data = new byte[buf.readableBytes()]; if (data.length > 0) { buf.readBytes(data); } } finally { buf.release(); } log.debug("Constructing '{}' with total of {} bytes of data", packet.getClass().getSimpleName(), data.length); //Return the backing array representation return data; } }