io.gomint.proxprox.network.tcp.PacketDecompressor.java Source code

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Here is the source code for io.gomint.proxprox.network.tcp.PacketDecompressor.java

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/*
 * Copyright (c) 2018, GoMint, BlackyPaw and geNAZt
 *
 * This code is licensed under the BSD license found in the
 * LICENSE file in the root directory of this source tree.
 */

package io.gomint.proxprox.network.tcp;

import com.google.common.base.Preconditions;
import io.gomint.server.jni.NativeCode;
import io.gomint.server.jni.zlib.JavaZLib;
import io.gomint.server.jni.zlib.NativeZLib;
import io.gomint.server.jni.zlib.ZLib;
import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.MessageToMessageDecoder;

import java.util.List;

/**
 * @author geNAZt
 * @version 1.0
 */
public class PacketDecompressor extends MessageToMessageDecoder<ByteBuf> {

    private static final NativeCode<ZLib> ZLIB_NATIVE = new NativeCode<>("zlib", JavaZLib.class, NativeZLib.class);

    static {
        ZLIB_NATIVE.load();
    }

    private final ZLib zlib = ZLIB_NATIVE.newInstance();

    @Override
    public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
        zlib.init(false, true, 0);
    }

    @Override
    public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
        zlib.free();
    }

    @Override
    protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
        int size = in.readInt();
        if (size == 0) {
            out.add(in.slice().retain());
            in.skipBytes(in.readableBytes());
        } else {
            ByteBuf decompressed = ctx.alloc().directBuffer();

            try {
                zlib.process(in, decompressed);
                Preconditions.checkState(decompressed.readableBytes() == size, "Decompressed packet size mismatch");

                out.add(decompressed);
                decompressed = null;
            } finally {
                if (decompressed != null) {
                    decompressed.release();
                }
            }
        }
    }

}