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	/*
	* Copyright (c) 1996, 2013, 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;

	import java.io.FilterInputStream;
	import java.io.InputStream;
	import java.io.IOException;
	import java.io.EOFException;

	/**
	* This class implements a stream filter for uncompressing data in the
	* "deflate" compression format. It is also used as the basis for other
	* decompression filters, such as GZIPInputStream.
	*
	* @see Inflater
	* @author David Connelly
	*/
	public
	class InflaterInputStream extends FilterInputStream {
	/**
	* Decompressor for this stream.
	*/
	protected Inflater inf;

	/**
	* Input buffer for decompression.
	*/
	protected byte[] buf;

	/**
	* Length of input buffer.
	*/
	protected int len;

	private boolean closed = false;
	// this flag is set to true after EOF has reached
	private boolean reachEOF = false;

	/**
	* Check to make sure that this stream has not been closed
	*/
	private void ensureOpen() throws IOException {
	if (closed) {
	throw new IOException("Stream closed");
	}
	}


	/**
	* Creates a new input stream with the specified decompressor and
	* buffer size.
	* @param in the input stream
	* @param inf the decompressor ("inflater")
	* @param size the input buffer size
	* @exception IllegalArgumentException if {@code size <= 0}
	*/
	public InflaterInputStream(InputStream in, Inflater inf, int size) {
	super(in);
	if (in == null \|\| inf == null) {
	throw new NullPointerException();
	} else if (size <= 0) {
	throw new IllegalArgumentException("buffer size <= 0");
	}
	this.inf = inf;
	buf = new byte[size];
	}

	/**
	* Creates a new input stream with the specified decompressor and a
	* default buffer size.
	* @param in the input stream
	* @param inf the decompressor ("inflater")
	*/
	public InflaterInputStream(InputStream in, Inflater inf) {
	this(in, inf, 512);
	}

	boolean usesDefaultInflater = false;

	/**
	* Creates a new input stream with a default decompressor and buffer size.
	* @param in the input stream
	*/
	public InflaterInputStream(InputStream in) {
	this(in, new Inflater());
	usesDefaultInflater = true;
	}

	private byte[] singleByteBuf = new byte[1];

	/**
	* Reads a byte of uncompressed data. This method will block until
	* enough input is available for decompression.
	* @return the byte read, or -1 if end of compressed input is reached
	* @exception IOException if an I/O error has occurred
	*/
	public int read() throws IOException {
	ensureOpen();
	return read(singleByteBuf, 0, 1) == -1 ? -1 : Byte.toUnsignedInt(singleByteBuf[0]);
	}

	/**
	* Reads uncompressed data into an array of bytes. If <code>len</code> is not
	* zero, the method will block until some input can be decompressed; otherwise,
	* no bytes are read and <code>0</code> is returned.
	* @param b the buffer into which the data is read
	* @param off the start offset in the destination array <code>b</code>
	* @param len the maximum number of bytes read
	* @return the actual number of bytes read, or -1 if the end of the
	* compressed input is reached or a preset dictionary is needed
	* @exception NullPointerException If <code>b</code> is <code>null</code>.
	* @exception IndexOutOfBoundsException If <code>off</code> is negative,
	* <code>len</code> is negative, or <code>len</code> is greater than
	* <code>b.length - off</code>
	* @exception ZipException if a ZIP format error has occurred
	* @exception IOException if an I/O error has occurred
	*/
	public int read(byte[] b, int off, int len) throws IOException {
	ensureOpen();
	if (b == null) {
	throw new NullPointerException();
	} else if (off < 0 \|\| len < 0 \|\| len > b.length - off) {
	throw new IndexOutOfBoundsException();
	} else if (len == 0) {
	return 0;
	}
	try {
	int n;
	while ((n = inf.inflate(b, off, len)) == 0) {
	if (inf.finished() \|\| inf.needsDictionary()) {
	reachEOF = true;
	return -1;
	}
	if (inf.needsInput()) {
	fill();
	}
	}
	return n;
	} catch (DataFormatException e) {
	String s = e.getMessage();
	throw new ZipException(s != null ? s : "Invalid ZLIB data format");
	}
	}

	/**
	* Returns 0 after EOF has been reached, otherwise always return 1.
	* <p>
	* Programs should not count on this method to return the actual number
	* of bytes that could be read without blocking.
	*
	* @return 1 before EOF and 0 after EOF.
	* @exception IOException if an I/O error occurs.
	*
	*/
	public int available() throws IOException {
	ensureOpen();
	if (reachEOF) {
	return 0;
	} else {
	return 1;
	}
	}

	private byte[] b = new byte[512];

	/**
	* Skips specified number of bytes of uncompressed data.
	* @param n the number of bytes to skip
	* @return the actual number of bytes skipped.
	* @exception IOException if an I/O error has occurred
	* @exception IllegalArgumentException if {@code n < 0}
	*/
	public long skip(long n) throws IOException {
	if (n < 0) {
	throw new IllegalArgumentException("negative skip length");
	}
	ensureOpen();
	int max = (int)Math.min(n, Integer.MAX_VALUE);
	int total = 0;
	while (total < max) {
	int len = max - total;
	if (len > b.length) {
	len = b.length;
	}
	len = read(b, 0, len);
	if (len == -1) {
	reachEOF = true;
	break;
	}
	total += len;
	}
	return total;
	}

	/**
	* Closes this input stream and releases any system resources associated
	* with the stream.
	* @exception IOException if an I/O error has occurred
	*/
	public void close() throws IOException {
	if (!closed) {
	if (usesDefaultInflater)
	inf.end();
	in.close();
	closed = true;
	}
	}

	/**
	* Fills input buffer with more data to decompress.
	* @exception IOException if an I/O error has occurred
	*/
	protected void fill() throws IOException {
	ensureOpen();
	len = in.read(buf, 0, buf.length);
	if (len == -1) {
	throw new EOFException("Unexpected end of ZLIB input stream");
	}
	inf.setInput(buf, 0, len);
	}

	/**
	* Tests if this input stream supports the <code>mark</code> and
	* <code>reset</code> methods. The <code>markSupported</code>
	* method of <code>InflaterInputStream</code> returns
	* <code>false</code>.
	*
	* @return a <code>boolean</code> indicating if this stream type supports
	* the <code>mark</code> and <code>reset</code> methods.
	* @see java.io.InputStream#mark(int)
	* @see java.io.InputStream#reset()
	*/
	public boolean markSupported() {
	return false;
	}

	/**
	* Marks the current position in this input stream.
	*
	* <p> The <code>mark</code> method of <code>InflaterInputStream</code>
	* does nothing.
	*
	* @param readlimit the maximum limit of bytes that can be read before
	* the mark position becomes invalid.
	* @see java.io.InputStream#reset()
	*/
	public synchronized void mark(int readlimit) {
	}

	/**
	* Repositions this stream to the position at the time the
	* <code>mark</code> method was last called on this input stream.
	*
	* <p> The method <code>reset</code> for class
	* <code>InflaterInputStream</code> does nothing except throw an
	* <code>IOException</code>.
	*
	* @exception IOException if this method is invoked.
	* @see java.io.InputStream#mark(int)
	* @see java.io.IOException
	*/
	public synchronized void reset() throws IOException {
	throw new IOException("mark/reset not supported");
	}
	}

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