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    • io.netty.handler.codec.compression.JZlibDecoder Maven / Gradle / Ivy

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    This artifact provides a single jar that contains all classes required to use remote Jakarta Enterprise Beans and Jakarta Messaging, including all dependencies. It is intended for use by those not using maven, maven users should just import the Jakarta Enterprise Beans and Jakarta Messaging BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

    There is a newer version: 35.0.0.Beta1
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    /*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project licenses this file to you 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 io.netty.handler.codec.compression;

import com.jcraft.jzlib.Inflater;
import com.jcraft.jzlib.JZlib;
import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;

import java.util.List;

public class JZlibDecoder extends ZlibDecoder {

    private final Inflater z = new Inflater();
    private byte[] dictionary;
    private volatile boolean finished;

    /**
     * Creates a new instance with the default wrapper ({@link ZlibWrapper#ZLIB}).
     *
     * @throws DecompressionException if failed to initialize zlib
     */
    public JZlibDecoder() {
        this(ZlibWrapper.ZLIB);
    }

    /**
     * Creates a new instance with the specified wrapper.
     *
     * @throws DecompressionException if failed to initialize zlib
     */
    public JZlibDecoder(ZlibWrapper wrapper) {
        if (wrapper == null) {
            throw new NullPointerException("wrapper");
        }

        int resultCode = z.init(ZlibUtil.convertWrapperType(wrapper));
        if (resultCode != JZlib.Z_OK) {
            ZlibUtil.fail(z, "initialization failure", resultCode);
        }
    }

    /**
     * Creates a new instance with the specified preset dictionary. The wrapper
     * is always {@link ZlibWrapper#ZLIB} because it is the only format that
     * supports the preset dictionary.
     *
     * @throws DecompressionException if failed to initialize zlib
     */
    public JZlibDecoder(byte[] dictionary) {
        if (dictionary == null) {
            throw new NullPointerException("dictionary");
        }
        this.dictionary = dictionary;

        int resultCode;
        resultCode = z.inflateInit(JZlib.W_ZLIB);
        if (resultCode != JZlib.Z_OK) {
            ZlibUtil.fail(z, "initialization failure", resultCode);
        }
    }

    /**
     * Returns {@code true} if and only if the end of the compressed stream
     * has been reached.
     */
    @Override
    public boolean isClosed() {
        return finished;
    }

    @Override
    protected void decode(ChannelHandlerContext ctx, ByteBuf in, List out) throws Exception {
        if (finished) {
            // Skip data received after finished.
            in.skipBytes(in.readableBytes());
            return;
        }

        final int inputLength = in.readableBytes();
        if (inputLength == 0) {
            return;
        }

        try {
            // Configure input.
            z.avail_in = inputLength;
            if (in.hasArray()) {
                z.next_in = in.array();
                z.next_in_index = in.arrayOffset() + in.readerIndex();
            } else {
                byte[] array = new byte[inputLength];
                in.getBytes(in.readerIndex(), array);
                z.next_in = array;
                z.next_in_index = 0;
            }
            int oldNextInIndex = z.next_in_index;

            // Configure output.
            int maxOutputLength = inputLength << 1;
            ByteBuf decompressed = ctx.alloc().heapBuffer(maxOutputLength);

            try {
                loop: for (;;) {
                    z.avail_out = maxOutputLength;
                    decompressed.ensureWritable(maxOutputLength);
                    z.next_out = decompressed.array();
                    z.next_out_index = decompressed.arrayOffset() + decompressed.writerIndex();
                    int oldNextOutIndex = z.next_out_index;

                    // Decompress 'in' into 'out'
                    int resultCode = z.inflate(JZlib.Z_SYNC_FLUSH);
                    int outputLength = z.next_out_index - oldNextOutIndex;
                    if (outputLength > 0) {
                        decompressed.writerIndex(decompressed.writerIndex() + outputLength);
                    }

                    switch (resultCode) {
                    case JZlib.Z_NEED_DICT:
                        if (dictionary == null) {
                            ZlibUtil.fail(z, "decompression failure", resultCode);
                        } else {
                            resultCode = z.inflateSetDictionary(dictionary, dictionary.length);
                            if (resultCode != JZlib.Z_OK) {
                                ZlibUtil.fail(z, "failed to set the dictionary", resultCode);
                            }
                        }
                        break;
                    case JZlib.Z_STREAM_END:
                        finished = true; // Do not decode anymore.
                        z.inflateEnd();
                        break loop;
                    case JZlib.Z_OK:
                        break;
                    case JZlib.Z_BUF_ERROR:
                        if (z.avail_in <= 0) {
                            break loop;
                        }
                        break;
                    default:
                        ZlibUtil.fail(z, "decompression failure", resultCode);
                    }
                }
            } finally {
                in.skipBytes(z.next_in_index - oldNextInIndex);
                if (decompressed.isReadable()) {
                    out.add(decompressed);
                } else {
                    decompressed.release();
                }
            }
        } finally {
            // Deference the external references explicitly to tell the VM that
            // the allocated byte arrays are temporary so that the call stack
            // can be utilized.
            // I'm not sure if the modern VMs do this optimization though.
            z.next_in = null;
            z.next_out = null;
        }
    }
}
    
    
    
    

    




    
    
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