ojluni/src/main/java/java/util/zip/Deflater.java - platform/libcore.git - Git at Google

 /*
  * Copyright (c) 1996, 2010, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this
  * particular file as subject to the "Classpath" exception as provided
  * by Oracle in the LICENSE file that accompanied this code.
  *
  * This code 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
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */

 package java.util.zip;

 /**
  * This class provides support for general purpose compression using the
  * popular ZLIB compression library. The ZLIB compression library was
  * initially developed as part of the PNG graphics standard and is not
  * protected by patents. It is fully described in the specifications at
  * the <a href="package-summary.html#package_description">java.util.zip
  * package description</a>.
  *
  * <p>The following code fragment demonstrates a trivial compression
  * and decompression of a string using <tt>Deflater</tt> and
  * <tt>Inflater</tt>.
  *
  * <blockquote><pre>
  * try {
  *     // Encode a String into bytes
  *     String inputString = "blahblahblah";
  *     byte[] input = inputString.getBytes("UTF-8");
  *
  *     // Compress the bytes
  *     byte[] output = new byte[100];
  *     Deflater compresser = new Deflater();
  *     compresser.setInput(input);
  *     compresser.finish();
  *     int compressedDataLength = compresser.deflate(output);
  *     compresser.end();
  *
  *     // Decompress the bytes
  *     Inflater decompresser = new Inflater();
  *     decompresser.setInput(output, 0, compressedDataLength);
  *     byte[] result = new byte[100];
  *     int resultLength = decompresser.inflate(result);
  *     decompresser.end();
  *
  *     // Decode the bytes into a String
  *     String outputString = new String(result, 0, resultLength, "UTF-8");
  * } catch(java.io.UnsupportedEncodingException ex) {
  *     // handle
  * } catch (java.util.zip.DataFormatException ex) {
  *     // handle
  * }
  * </pre></blockquote>
  *
  * @see         Inflater
  * @author      David Connelly
  */
 public
 class Deflater {

     private final ZStreamRef zsRef;
     private byte[] buf = new byte[0];
     private int off, len;
     private int level, strategy;
     private boolean setParams;
     private boolean finish, finished;
     private long bytesRead;
     private long bytesWritten;

     /**
      * Compression method for the deflate algorithm (the only one currently
      * supported).
      */
     public static final int DEFLATED = 8;

     /**
      * Compression level for no compression.
      */
     public static final int NO_COMPRESSION = 0;

     /**
      * Compression level for fastest compression.
      */
     public static final int BEST_SPEED = 1;

     /**
      * Compression level for best compression.
      */
     public static final int BEST_COMPRESSION = 9;

     /**
      * Default compression level.
      */
     public static final int DEFAULT_COMPRESSION = -1;

     /**
      * Compression strategy best used for data consisting mostly of small
      * values with a somewhat random distribution. Forces more Huffman coding
      * and less string matching.
      */
     public static final int FILTERED = 1;

     /**
      * Compression strategy for Huffman coding only.
      */
     public static final int HUFFMAN_ONLY = 2;

     /**
      * Default compression strategy.
      */
     public static final int DEFAULT_STRATEGY = 0;

     /**
      * Compression flush mode used to achieve best compression result.
      *
      * @see Deflater#deflate(byte[], int, int, int)
      * @since 1.7
      */
     public static final int NO_FLUSH = 0;

     /**
      * Compression flush mode used to flush out all pending output; may
      * degrade compression for some compression algorithms.
      *
      * @see Deflater#deflate(byte[], int, int, int)
      * @since 1.7
      */
     public static final int SYNC_FLUSH = 2;

     /**
      * Compression flush mode used to flush out all pending output and
      * reset the deflater. Using this mode too often can seriously degrade
      * compression.
      *
      * @see Deflater#deflate(byte[], int, int, int)
      * @since 1.7
      */
     public static final int FULL_FLUSH = 3;

     static {
         /* Zip library is loaded from System.initializeSystemClass */
         initIDs();
     }

     /**
      * Creates a new compressor using the specified compression level.
      * If 'nowrap' is true then the ZLIB header and checksum fields will
      * not be used in order to support the compression format used in
      * both GZIP and PKZIP.
      * @param level the compression level (0-9)
      * @param nowrap if true then use GZIP compatible compression
      */
     public Deflater(int level, boolean nowrap) {
         this.level = level;
         this.strategy = DEFAULT_STRATEGY;
         this.zsRef = new ZStreamRef(init(level, DEFAULT_STRATEGY, nowrap));
     }

     /**
      * Creates a new compressor using the specified compression level.
      * Compressed data will be generated in ZLIB format.
      * @param level the compression level (0-9)
      */
     public Deflater(int level) {
         this(level, false);
     }

     /**
      * Creates a new compressor with the default compression level.
      * Compressed data will be generated in ZLIB format.
      */
     public Deflater() {
         this(DEFAULT_COMPRESSION, false);
     }

     /**
      * Sets input data for compression. This should be called whenever
      * needsInput() returns true indicating that more input data is required.
      * @param b the input data bytes
      * @param off the start offset of the data
      * @param len the length of the data
      * @see Deflater#needsInput
      */
     public void setInput(byte[] b, int off, int len) {
         if (b== null) {
             throw new NullPointerException();
         }
         if (off < 0 || len < 0 || off > b.length - len) {
             throw new ArrayIndexOutOfBoundsException();
         }
         synchronized (zsRef) {
             this.buf = b;
             this.off = off;
             this.len = len;
         }
     }

     /**
      * Sets input data for compression. This should be called whenever
      * needsInput() returns true indicating that more input data is required.
      * @param b the input data bytes
      * @see Deflater#needsInput
      */
     public void setInput(byte[] b) {
         setInput(b, 0, b.length);
     }

     /**
      * Sets preset dictionary for compression. A preset dictionary is used
      * when the history buffer can be predetermined. When the data is later
      * uncompressed with Inflater.inflate(), Inflater.getAdler() can be called
      * in order to get the Adler-32 value of the dictionary required for
      * decompression.
      * @param b the dictionary data bytes
      * @param off the start offset of the data
      * @param len the length of the data
      * @see Inflater#inflate
      * @see Inflater#getAdler
      */
     public void setDictionary(byte[] b, int off, int len) {
         if (b == null) {
             throw new NullPointerException();
         }
         if (off < 0 || len < 0 || off > b.length - len) {
             throw new ArrayIndexOutOfBoundsException();
         }
         synchronized (zsRef) {
             ensureOpen();
             setDictionary(zsRef.address(), b, off, len);
         }
     }

     /**
      * Sets preset dictionary for compression. A preset dictionary is used
      * when the history buffer can be predetermined. When the data is later
      * uncompressed with Inflater.inflate(), Inflater.getAdler() can be called
      * in order to get the Adler-32 value of the dictionary required for
      * decompression.
      * @param b the dictionary data bytes
      * @see Inflater#inflate
      * @see Inflater#getAdler
      */
     public void setDictionary(byte[] b) {
         setDictionary(b, 0, b.length);
     }

     /**
      * Sets the compression strategy to the specified value.
      * @param strategy the new compression strategy
      * @exception IllegalArgumentException if the compression strategy is
      *                                     invalid
      */
     public void setStrategy(int strategy) {
         switch (strategy) {
           case DEFAULT_STRATEGY:
           case FILTERED:
           case HUFFMAN_ONLY:
             break;
           default:
             throw new IllegalArgumentException();
         }
         synchronized (zsRef) {
             if (this.strategy != strategy) {
                 this.strategy = strategy;
                 setParams = true;
             }
         }
     }

     /**
      * Sets the current compression level to the specified value.
      * @param level the new compression level (0-9)
      * @exception IllegalArgumentException if the compression level is invalid
      */
     public void setLevel(int level) {
         if ((level < 0 || level > 9) && level != DEFAULT_COMPRESSION) {
             throw new IllegalArgumentException("invalid compression level");
         }
         synchronized (zsRef) {
             if (this.level != level) {
                 this.level = level;
                 setParams = true;
             }
         }
     }

     /**
      * Returns true if the input data buffer is empty and setInput()
      * should be called in order to provide more input.
      * @return true if the input data buffer is empty and setInput()
      * should be called in order to provide more input
      */
     public boolean needsInput() {
         return len <= 0;
     }

     /**
      * When called, indicates that compression should end with the current
      * contents of the input buffer.
      */
     public void finish() {
         synchronized (zsRef) {
             finish = true;
         }
     }

     /**
      * Returns true if the end of the compressed data output stream has
      * been reached.
      * @return true if the end of the compressed data output stream has
      * been reached
      */
     public boolean finished() {
         synchronized (zsRef) {
             return finished;
         }
     }

     /**
      * Compresses the input data and fills specified buffer with compressed
      * data. Returns actual number of bytes of compressed data. A return value
      * of 0 indicates that {@link #needsInput() needsInput} should be called
      * in order to determine if more input data is required.
      *
      * <p>This method uses {@link #NO_FLUSH} as its compression flush mode.
      * An invocation of this method of the form {@code deflater.deflate(b, off, len)}
      * yields the same result as the invocation of
      * {@code deflater.deflate(b, off, len, Deflater.NO_FLUSH)}.
      *
      * @param b the buffer for the compressed data
      * @param off the start offset of the data
      * @param len the maximum number of bytes of compressed data
      * @return the actual number of bytes of compressed data written to the
      *         output buffer
      */
     public int deflate(byte[] b, int off, int len) {
         return deflate(b, off, len, NO_FLUSH);
     }

     /**
      * Compresses the input data and fills specified buffer with compressed
      * data. Returns actual number of bytes of compressed data. A return value
      * of 0 indicates that {@link #needsInput() needsInput} should be called
      * in order to determine if more input data is required.
      *
      * <p>This method uses {@link #NO_FLUSH} as its compression flush mode.
      * An invocation of this method of the form {@code deflater.deflate(b)}
      * yields the same result as the invocation of
      * {@code deflater.deflate(b, 0, b.length, Deflater.NO_FLUSH)}.
      *
      * @param b the buffer for the compressed data
      * @return the actual number of bytes of compressed data written to the
      *         output buffer
      */
     public int deflate(byte[] b) {
         return deflate(b, 0, b.length, NO_FLUSH);
     }

     /**
      * Compresses the input data and fills the specified buffer with compressed
      * data. Returns actual number of bytes of data compressed.
      *
      * <p>Compression flush mode is one of the following three modes:
      *
      * <ul>
      * <li>{@link #NO_FLUSH}: allows the deflater to decide how much data
      * to accumulate, before producing output, in order to achieve the best
      * compression (should be used in normal use scenario). A return value
      * of 0 in this flush mode indicates that {@link #needsInput()} should
      * be called in order to determine if more input data is required.
      *
      * <li>{@link #SYNC_FLUSH}: all pending output in the deflater is flushed,
      * to the specified output buffer, so that an inflater that works on
      * compressed data can get all input data available so far (In particular
      * the {@link #needsInput()} returns {@code true} after this invocation
      * if enough output space is provided). Flushing with {@link #SYNC_FLUSH}
      * may degrade compression for some compression algorithms and so it
      * should be used only when necessary.
      *
      * <li>{@link #FULL_FLUSH}: all pending output is flushed out as with
      * {@link #SYNC_FLUSH}. The compression state is reset so that the inflater
      * that works on the compressed output data can restart from this point
      * if previous compressed data has been damaged or if random access is
      * desired. Using {@link #FULL_FLUSH} too often can seriously degrade
      * compression.
      * </ul>
      *
      * <p>In the case of {@link #FULL_FLUSH} or {@link #SYNC_FLUSH}, if
      * the return value is {@code len}, the space available in output
      * buffer {@code b}, this method should be invoked again with the same
      * {@code flush} parameter and more output space.
      *
      * @param b the buffer for the compressed data
      * @param off the start offset of the data
      * @param len the maximum number of bytes of compressed data
      * @param flush the compression flush mode
      * @return the actual number of bytes of compressed data written to
      *         the output buffer
      *
      * @throws IllegalArgumentException if the flush mode is invalid
      * @since 1.7
      */
     public int deflate(byte[] b, int off, int len, int flush) {
         if (b == null) {
             throw new NullPointerException();
         }
         if (off < 0 || len < 0 || off > b.length - len) {
             throw new ArrayIndexOutOfBoundsException();
         }
         synchronized (zsRef) {
             ensureOpen();
             if (flush == NO_FLUSH || flush == SYNC_FLUSH ||
                 flush == FULL_FLUSH) {
                 int thisLen = this.len;
                 int n = deflateBytes(zsRef.address(), b, off, len, flush);
                 bytesWritten += n;
                 bytesRead += (thisLen - this.len);
                 return n;
             }
             throw new IllegalArgumentException();
         }
     }

     /**
      * Returns the ADLER-32 value of the uncompressed data.
      * @return the ADLER-32 value of the uncompressed data
      */
     public int getAdler() {
         synchronized (zsRef) {
             ensureOpen();
             return getAdler(zsRef.address());
         }
     }

     /**
      * Returns the total number of uncompressed bytes input so far.
      *
      * <p>Since the number of bytes may be greater than
      * Integer.MAX_VALUE, the {@link #getBytesRead()} method is now
      * the preferred means of obtaining this information.</p>
      *
      * @return the total number of uncompressed bytes input so far
      */
     public int getTotalIn() {
         return (int) getBytesRead();
     }

     /**
      * Returns the total number of uncompressed bytes input so far.</p>
      *
      * @return the total (non-negative) number of uncompressed bytes input so far
      * @since 1.5
      */
     public long getBytesRead() {
         synchronized (zsRef) {
             ensureOpen();
             return bytesRead;
         }
     }

     /**
      * Returns the total number of compressed bytes output so far.
      *
      * <p>Since the number of bytes may be greater than
      * Integer.MAX_VALUE, the {@link #getBytesWritten()} method is now
      * the preferred means of obtaining this information.</p>
      *
      * @return the total number of compressed bytes output so far
      */
     public int getTotalOut() {
         return (int) getBytesWritten();
     }

     /**
      * Returns the total number of compressed bytes output so far.</p>
      *
      * @return the total (non-negative) number of compressed bytes output so far
      * @since 1.5
      */
     public long getBytesWritten() {
         synchronized (zsRef) {
             ensureOpen();
             return bytesWritten;
         }
     }

     /**
      * Resets deflater so that a new set of input data can be processed.
      * Keeps current compression level and strategy settings.
      */
     public void reset() {
         synchronized (zsRef) {
             ensureOpen();
             reset(zsRef.address());
             finish = false;
             finished = false;
             off = len = 0;
             bytesRead = bytesWritten = 0;
         }
     }

     /**
      * Closes the compressor and discards any unprocessed input.
      * This method should be called when the compressor is no longer
      * being used, but will also be called automatically by the
      * finalize() method. Once this method is called, the behavior
      * of the Deflater object is undefined.
      */
     public void end() {
         synchronized (zsRef) {
             long addr = zsRef.address();
             zsRef.clear();
             if (addr != 0) {
                 end(addr);
                 buf = null;
             }
         }
     }

     /**
      * Closes the compressor when garbage is collected.
      */
     protected void finalize() {
         end();
     }

     private void ensureOpen() {
         assert Thread.holdsLock(zsRef);
         if (zsRef.address() == 0)
             throw new NullPointerException("Deflater has been closed");
     }

     private static native void initIDs();
     private native static long init(int level, int strategy, boolean nowrap);
     private native static void setDictionary(long addr, byte[] b, int off, int len);
     private native int deflateBytes(long addr, byte[] b, int off, int len,
                                     int flush);
     private native static int getAdler(long addr);
     private native static void reset(long addr);
     private native static void end(long addr);
 }
	/*
	* Copyright (c) 1996, 2010, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code 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
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package java.util.zip;

	/**
	* This class provides support for general purpose compression using the
	* popular ZLIB compression library. The ZLIB compression library was
	* initially developed as part of the PNG graphics standard and is not
	* protected by patents. It is fully described in the specifications at
	* the <a href="package-summary.html#package_description">java.util.zip
	* package description</a>.
	*
	* <p>The following code fragment demonstrates a trivial compression
	* and decompression of a string using <tt>Deflater</tt> and
	* <tt>Inflater</tt>.
	*
	* <blockquote><pre>
	* try {
	* // Encode a String into bytes
	* String inputString = "blahblahblah";
	* byte[] input = inputString.getBytes("UTF-8");
	*
	* // Compress the bytes
	* byte[] output = new byte[100];
	* Deflater compresser = new Deflater();
	* compresser.setInput(input);
	* compresser.finish();
	* int compressedDataLength = compresser.deflate(output);
	* compresser.end();
	*
	* // Decompress the bytes
	* Inflater decompresser = new Inflater();
	* decompresser.setInput(output, 0, compressedDataLength);
	* byte[] result = new byte[100];
	* int resultLength = decompresser.inflate(result);
	* decompresser.end();
	*
	* // Decode the bytes into a String
	* String outputString = new String(result, 0, resultLength, "UTF-8");
	* } catch(java.io.UnsupportedEncodingException ex) {
	* // handle
	* } catch (java.util.zip.DataFormatException ex) {
	* // handle
	* }
	* </pre></blockquote>
	*
	* @see Inflater
	* @author David Connelly
	*/
	public
	class Deflater {

	private final ZStreamRef zsRef;
	private byte[] buf = new byte[0];
	private int off, len;
	private int level, strategy;
	private boolean setParams;
	private boolean finish, finished;
	private long bytesRead;
	private long bytesWritten;

	/**
	* Compression method for the deflate algorithm (the only one currently
	* supported).
	*/
	public static final int DEFLATED = 8;

	/**
	* Compression level for no compression.
	*/
	public static final int NO_COMPRESSION = 0;

	/**
	* Compression level for fastest compression.
	*/
	public static final int BEST_SPEED = 1;

	/**
	* Compression level for best compression.
	*/
	public static final int BEST_COMPRESSION = 9;

	/**
	* Default compression level.
	*/
	public static final int DEFAULT_COMPRESSION = -1;

	/**
	* Compression strategy best used for data consisting mostly of small
	* values with a somewhat random distribution. Forces more Huffman coding
	* and less string matching.
	*/
	public static final int FILTERED = 1;

	/**
	* Compression strategy for Huffman coding only.
	*/
	public static final int HUFFMAN_ONLY = 2;

	/**
	* Default compression strategy.
	*/
	public static final int DEFAULT_STRATEGY = 0;

	/**
	* Compression flush mode used to achieve best compression result.
	*
	* @see Deflater#deflate(byte[], int, int, int)
	* @since 1.7
	*/
	public static final int NO_FLUSH = 0;

	/**
	* Compression flush mode used to flush out all pending output; may
	* degrade compression for some compression algorithms.
	*
	* @see Deflater#deflate(byte[], int, int, int)
	* @since 1.7
	*/
	public static final int SYNC_FLUSH = 2;

	/**
	* Compression flush mode used to flush out all pending output and
	* reset the deflater. Using this mode too often can seriously degrade
	* compression.
	*
	* @see Deflater#deflate(byte[], int, int, int)
	* @since 1.7
	*/
	public static final int FULL_FLUSH = 3;

	static {
	/* Zip library is loaded from System.initializeSystemClass */
	initIDs();
	}

	/**
	* Creates a new compressor using the specified compression level.
	* If 'nowrap' is true then the ZLIB header and checksum fields will
	* not be used in order to support the compression format used in
	* both GZIP and PKZIP.
	* @param level the compression level (0-9)
	* @param nowrap if true then use GZIP compatible compression
	*/
	public Deflater(int level, boolean nowrap) {
	this.level = level;
	this.strategy = DEFAULT_STRATEGY;
	this.zsRef = new ZStreamRef(init(level, DEFAULT_STRATEGY, nowrap));
	}

	/**
	* Creates a new compressor using the specified compression level.
	* Compressed data will be generated in ZLIB format.
	* @param level the compression level (0-9)
	*/
	public Deflater(int level) {
	this(level, false);
	}

	/**
	* Creates a new compressor with the default compression level.
	* Compressed data will be generated in ZLIB format.
	*/
	public Deflater() {
	this(DEFAULT_COMPRESSION, false);
	}

	/**
	* Sets input data for compression. This should be called whenever
	* needsInput() returns true indicating that more input data is required.
	* @param b the input data bytes
	* @param off the start offset of the data
	* @param len the length of the data
	* @see Deflater#needsInput
	*/
	public void setInput(byte[] b, int off, int len) {
	if (b== null) {
	throw new NullPointerException();
	}
	if (off < 0 \|\| len < 0 \|\| off > b.length - len) {
	throw new ArrayIndexOutOfBoundsException();
	}
	synchronized (zsRef) {
	this.buf = b;
	this.off = off;
	this.len = len;
	}
	}

	/**
	* Sets input data for compression. This should be called whenever
	* needsInput() returns true indicating that more input data is required.
	* @param b the input data bytes
	* @see Deflater#needsInput
	*/
	public void setInput(byte[] b) {
	setInput(b, 0, b.length);
	}

	/**
	* Sets preset dictionary for compression. A preset dictionary is used
	* when the history buffer can be predetermined. When the data is later
	* uncompressed with Inflater.inflate(), Inflater.getAdler() can be called
	* in order to get the Adler-32 value of the dictionary required for
	* decompression.
	* @param b the dictionary data bytes
	* @param off the start offset of the data
	* @param len the length of the data
	* @see Inflater#inflate
	* @see Inflater#getAdler
	*/
	public void setDictionary(byte[] b, int off, int len) {
	if (b == null) {
	throw new NullPointerException();
	}
	if (off < 0 \|\| len < 0 \|\| off > b.length - len) {
	throw new ArrayIndexOutOfBoundsException();
	}
	synchronized (zsRef) {
	ensureOpen();
	setDictionary(zsRef.address(), b, off, len);
	}
	}

	/**
	* Sets preset dictionary for compression. A preset dictionary is used
	* when the history buffer can be predetermined. When the data is later
	* uncompressed with Inflater.inflate(), Inflater.getAdler() can be called
	* in order to get the Adler-32 value of the dictionary required for
	* decompression.
	* @param b the dictionary data bytes
	* @see Inflater#inflate
	* @see Inflater#getAdler
	*/
	public void setDictionary(byte[] b) {
	setDictionary(b, 0, b.length);
	}

	/**
	* Sets the compression strategy to the specified value.
	* @param strategy the new compression strategy
	* @exception IllegalArgumentException if the compression strategy is
	* invalid
	*/
	public void setStrategy(int strategy) {
	switch (strategy) {
	case DEFAULT_STRATEGY:
	case FILTERED:
	case HUFFMAN_ONLY:
	break;
	default:
	throw new IllegalArgumentException();
	}
	synchronized (zsRef) {
	if (this.strategy != strategy) {
	this.strategy = strategy;
	setParams = true;
	}
	}
	}

	/**
	* Sets the current compression level to the specified value.
	* @param level the new compression level (0-9)
	* @exception IllegalArgumentException if the compression level is invalid
	*/
	public void setLevel(int level) {
	if ((level < 0 \|\| level > 9) && level != DEFAULT_COMPRESSION) {
	throw new IllegalArgumentException("invalid compression level");
	}
	synchronized (zsRef) {
	if (this.level != level) {
	this.level = level;
	setParams = true;
	}
	}
	}

	/**
	* Returns true if the input data buffer is empty and setInput()
	* should be called in order to provide more input.
	* @return true if the input data buffer is empty and setInput()
	* should be called in order to provide more input
	*/
	public boolean needsInput() {
	return len <= 0;
	}

	/**
	* When called, indicates that compression should end with the current
	* contents of the input buffer.
	*/
	public void finish() {
	synchronized (zsRef) {
	finish = true;
	}
	}

	/**
	* Returns true if the end of the compressed data output stream has
	* been reached.
	* @return true if the end of the compressed data output stream has
	* been reached
	*/
	public boolean finished() {
	synchronized (zsRef) {
	return finished;
	}
	}

	/**
	* Compresses the input data and fills specified buffer with compressed
	* data. Returns actual number of bytes of compressed data. A return value
	* of 0 indicates that {@link #needsInput() needsInput} should be called
	* in order to determine if more input data is required.
	*
	* <p>This method uses {@link #NO_FLUSH} as its compression flush mode.
	* An invocation of this method of the form {@code deflater.deflate(b, off, len)}
	* yields the same result as the invocation of
	* {@code deflater.deflate(b, off, len, Deflater.NO_FLUSH)}.
	*
	* @param b the buffer for the compressed data
	* @param off the start offset of the data
	* @param len the maximum number of bytes of compressed data
	* @return the actual number of bytes of compressed data written to the
	* output buffer
	*/
	public int deflate(byte[] b, int off, int len) {
	return deflate(b, off, len, NO_FLUSH);
	}

	/**
	* Compresses the input data and fills specified buffer with compressed
	* data. Returns actual number of bytes of compressed data. A return value
	* of 0 indicates that {@link #needsInput() needsInput} should be called
	* in order to determine if more input data is required.
	*
	* <p>This method uses {@link #NO_FLUSH} as its compression flush mode.
	* An invocation of this method of the form {@code deflater.deflate(b)}
	* yields the same result as the invocation of
	* {@code deflater.deflate(b, 0, b.length, Deflater.NO_FLUSH)}.
	*
	* @param b the buffer for the compressed data
	* @return the actual number of bytes of compressed data written to the
	* output buffer
	*/
	public int deflate(byte[] b) {
	return deflate(b, 0, b.length, NO_FLUSH);
	}

	/**
	* Compresses the input data and fills the specified buffer with compressed
	* data. Returns actual number of bytes of data compressed.
	*
	* <p>Compression flush mode is one of the following three modes:
	*
	* <ul>
	* <li>{@link #NO_FLUSH}: allows the deflater to decide how much data
	* to accumulate, before producing output, in order to achieve the best
	* compression (should be used in normal use scenario). A return value
	* of 0 in this flush mode indicates that {@link #needsInput()} should
	* be called in order to determine if more input data is required.
	*
	* <li>{@link #SYNC_FLUSH}: all pending output in the deflater is flushed,
	* to the specified output buffer, so that an inflater that works on
	* compressed data can get all input data available so far (In particular
	* the {@link #needsInput()} returns {@code true} after this invocation
	* if enough output space is provided). Flushing with {@link #SYNC_FLUSH}
	* may degrade compression for some compression algorithms and so it
	* should be used only when necessary.
	*
	* <li>{@link #FULL_FLUSH}: all pending output is flushed out as with
	* {@link #SYNC_FLUSH}. The compression state is reset so that the inflater
	* that works on the compressed output data can restart from this point
	* if previous compressed data has been damaged or if random access is
	* desired. Using {@link #FULL_FLUSH} too often can seriously degrade
	* compression.
	* </ul>
	*
	* <p>In the case of {@link #FULL_FLUSH} or {@link #SYNC_FLUSH}, if
	* the return value is {@code len}, the space available in output
	* buffer {@code b}, this method should be invoked again with the same
	* {@code flush} parameter and more output space.
	*
	* @param b the buffer for the compressed data
	* @param off the start offset of the data
	* @param len the maximum number of bytes of compressed data
	* @param flush the compression flush mode
	* @return the actual number of bytes of compressed data written to
	* the output buffer
	*
	* @throws IllegalArgumentException if the flush mode is invalid
	* @since 1.7
	*/
	public int deflate(byte[] b, int off, int len, int flush) {
	if (b == null) {
	throw new NullPointerException();
	}
	if (off < 0 \|\| len < 0 \|\| off > b.length - len) {
	throw new ArrayIndexOutOfBoundsException();
	}
	synchronized (zsRef) {
	ensureOpen();
	if (flush == NO_FLUSH \|\| flush == SYNC_FLUSH \|\|
	flush == FULL_FLUSH) {
	int thisLen = this.len;
	int n = deflateBytes(zsRef.address(), b, off, len, flush);
	bytesWritten += n;
	bytesRead += (thisLen - this.len);
	return n;
	}
	throw new IllegalArgumentException();
	}
	}

	/**
	* Returns the ADLER-32 value of the uncompressed data.
	* @return the ADLER-32 value of the uncompressed data
	*/
	public int getAdler() {
	synchronized (zsRef) {
	ensureOpen();
	return getAdler(zsRef.address());
	}
	}

	/**
	* Returns the total number of uncompressed bytes input so far.
	*
	* <p>Since the number of bytes may be greater than
	* Integer.MAX_VALUE, the {@link #getBytesRead()} method is now
	* the preferred means of obtaining this information.</p>
	*
	* @return the total number of uncompressed bytes input so far
	*/
	public int getTotalIn() {
	return (int) getBytesRead();
	}

	/**
	* Returns the total number of uncompressed bytes input so far.</p>
	*
	* @return the total (non-negative) number of uncompressed bytes input so far
	* @since 1.5
	*/
	public long getBytesRead() {
	synchronized (zsRef) {
	ensureOpen();
	return bytesRead;
	}
	}

	/**
	* Returns the total number of compressed bytes output so far.
	*
	* <p>Since the number of bytes may be greater than
	* Integer.MAX_VALUE, the {@link #getBytesWritten()} method is now
	* the preferred means of obtaining this information.</p>
	*
	* @return the total number of compressed bytes output so far
	*/
	public int getTotalOut() {
	return (int) getBytesWritten();
	}

	/**
	* Returns the total number of compressed bytes output so far.</p>
	*
	* @return the total (non-negative) number of compressed bytes output so far
	* @since 1.5
	*/
	public long getBytesWritten() {
	synchronized (zsRef) {
	ensureOpen();
	return bytesWritten;
	}
	}

	/**
	* Resets deflater so that a new set of input data can be processed.
	* Keeps current compression level and strategy settings.
	*/
	public void reset() {
	synchronized (zsRef) {
	ensureOpen();
	reset(zsRef.address());
	finish = false;
	finished = false;
	off = len = 0;
	bytesRead = bytesWritten = 0;
	}
	}

	/**
	* Closes the compressor and discards any unprocessed input.
	* This method should be called when the compressor is no longer
	* being used, but will also be called automatically by the
	* finalize() method. Once this method is called, the behavior
	* of the Deflater object is undefined.
	*/
	public void end() {
	synchronized (zsRef) {
	long addr = zsRef.address();
	zsRef.clear();
	if (addr != 0) {
	end(addr);
	buf = null;
	}
	}
	}

	/**
	* Closes the compressor when garbage is collected.
	*/
	protected void finalize() {
	end();
	}

	private void ensureOpen() {
	assert Thread.holdsLock(zsRef);
	if (zsRef.address() == 0)
	throw new NullPointerException("Deflater has been closed");
	}

	private static native void initIDs();
	private native static long init(int level, int strategy, boolean nowrap);
	private native static void setDictionary(long addr, byte[] b, int off, int len);
	private native int deflateBytes(long addr, byte[] b, int off, int len,
	int flush);
	private native static int getAdler(long addr);
	private native static void reset(long addr);
	private native static void end(long addr);
	}