content: /*
   * Copyright (c) 2019-2020 5zig Reborn
   * Copyright (c) 2015-2019 5zig
   *
   * This file is part of The 5zig Mod
   * The 5zig Mod is free software: you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation, either version 3 of the License, or
   * (at your option) any later version.
   *
   * The 5zig Mod is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with The 5zig Mod.  If not, see <http://www.gnu.org/licenses/>.
   */
  
  package eu.the5zig.mod.chat.network;
  
  import eu.the5zig.mod.chat.network.packets.PacketBuffer;
  import io.netty.buffer.ByteBuf;
  import io.netty.channel.ChannelHandlerContext;
  import io.netty.handler.codec.MessageToByteEncoder;
  
  import java.util.zip.Deflater;
  
  public class NetworkCompressionEncoder extends MessageToByteEncoder<ByteBuf> {
  
  	private final byte[] buffer = new byte[8192];
  	private final Deflater deflater;
  	private int threshold;
  
  	public NetworkCompressionEncoder(int threshold) {
  		this.threshold = threshold;
  		this.deflater = new Deflater();
  	}
  
  	@Override
  	public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
  		this.deflater.end();
  	}
  
  	protected void encode(ChannelHandlerContext ctx, ByteBuf in, ByteBuf out) {
  		int length = in.readableBytes();
  
  		if (length < this.threshold) {
  			PacketBuffer.writeVarIntToBuffer(out, 0);
  			out.writeBytes(in);
  		} else {
  			byte[] uncompressedData = new byte[length];
  			in.readBytes(uncompressedData);
  			PacketBuffer.writeVarIntToBuffer(out, uncompressedData.length);
  			this.deflater.setInput(uncompressedData, 0, length);
  			this.deflater.finish();
  
  			while (!this.deflater.finished()) {
  				int compressedLength = this.deflater.deflate(this.buffer);
  				out.writeBytes(this.buffer, 0, compressedLength);
  			}
  
  			this.deflater.reset();
  		}
  	}
  
  	public void setCompressionTreshold(int treshold) {
  		this.threshold = treshold;
  	}
  
  }