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The file system driver family for TAR and related archive file types. Add the JAR artifact of this module to the run time class path to make its file system drivers available for service location in the client API modules.

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/*
 * Copyright (C) 2005-2013 Schlichtherle IT Services.
 * All rights reserved. Use is subject to license terms.
 */
package de.schlichtherle.truezip.fs.archive.tar;

import de.schlichtherle.truezip.entry.Entry;
import de.schlichtherle.truezip.fs.FsController;
import de.schlichtherle.truezip.fs.FsEntryName;
import de.schlichtherle.truezip.fs.FsModel;
import de.schlichtherle.truezip.fs.FsOutputOption;
import static de.schlichtherle.truezip.fs.FsOutputOption.STORE;
import de.schlichtherle.truezip.io.Streams;
import de.schlichtherle.truezip.socket.IOPoolProvider;
import de.schlichtherle.truezip.socket.OutputSocket;
import de.schlichtherle.truezip.util.BitField;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.zip.Deflater;
import java.util.zip.GZIPInputStream;
import javax.annotation.CheckForNull;
import javax.annotation.concurrent.Immutable;

/**
 * An archive driver for GZIP compressed TAR files (TAR.GZIP).
 * 
 * Subclasses must be thread-safe and should be immutable!
 * 
 * @author Christian Schlichtherle
 */
@Immutable
public class TarGZipDriver extends TarDriver {

    public TarGZipDriver(IOPoolProvider provider) {
        super(provider);
    }

    /**
     * The buffer size used for reading and writing.
     * Optimized for performance.
     */
    public static final int BUFFER_SIZE = Streams.BUFFER_SIZE;

    /**
     * Returns the size of the I/O buffer.
     * 

     * The implementation in the class {@link TarGZipDriver} returns
     * {@link #BUFFER_SIZE}.
     *
     * @return The size of the I/O buffer.
     */
    public int getBufferSize() {
        return BUFFER_SIZE;
    }

    /**
     * Returns the compression level to use when writing a GZIP output stream.
     * 
     * The implementation in the class {@link TarBZip2Driver} returns
     * {@link Deflater#BEST_COMPRESSION}.
     * 
     * @return The compression level to use when writing a GZIP output stream.
     */
    public int getLevel() {
        return Deflater.BEST_COMPRESSION;
    }

    /**
     * Sets {@link FsOutputOption#STORE} in {@code options} before
     * forwarding the call to {@code controller}.
     */
    @Override
    public OutputSocket getOutputSocket( FsController controller,
                                            FsEntryName name,
                                            BitField options,
                                            @CheckForNull Entry template) {
        return controller.getOutputSocket(name, options.set(STORE), template);
    }

    @Override
    protected TarInputShop newTarInputShop(FsModel model, InputStream in)
    throws IOException {
        return super.newTarInputShop(model,
                new GZIPInputStream(in, getBufferSize()));
    }

    @Override
    protected TarOutputShop newTarOutputShop(
            final FsModel model,
            final OutputStream out,
            final TarInputShop source)
    throws IOException {
        return super.newTarOutputShop(model,
                new GZIPOutputStream(out, getBufferSize(), getLevel()),
                source);
    }

    /** Extends its super class to set the deflater level. */
    private static final class GZIPOutputStream
    extends java.util.zip.GZIPOutputStream {
        GZIPOutputStream(OutputStream out, int size, int level)
        throws IOException {
            super(out, size);
            def.setLevel(level);
        }
    } // GZIPOutputStream
}