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	/*
	* Copyright (c) 1994, 2004, 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 sun.net.www;

	import java.net.URL;
	import java.util.*;
	import java.io.*;
	import sun.net.ProgressSource;
	import sun.net.www.http.ChunkedInputStream;


	public class MeteredStream extends FilterInputStream {

	// Instance variables.
	/* if expected != -1, after we've read >= expected, we're "closed" and return -1
	* from subsequest read() 's
	*/
	protected boolean closed = false;
	protected long expected;
	protected long count = 0;
	protected long markedCount = 0;
	protected int markLimit = -1;
	protected ProgressSource pi;

	public MeteredStream(InputStream is, ProgressSource pi, long expected)
	{
	super(is);

	this.pi = pi;
	this.expected = expected;

	if (pi != null) {
	pi.updateProgress(0, expected);
	}
	}

	private final void justRead(long n) throws IOException {
	if (n == -1) {

	/*
	* don't close automatically when mark is set and is valid;
	* cannot reset() after close()
	*/
	if (!isMarked()) {
	close();
	}
	return;
	}

	count += n;

	/**
	* If read beyond the markLimit, invalidate the mark
	*/
	if (count - markedCount > markLimit) {
	markLimit = -1;
	}

	if (pi != null)
	pi.updateProgress(count, expected);

	if (isMarked()) {
	return;
	}

	// if expected length is known, we could determine if
	// read overrun.
	if (expected > 0) {
	if (count >= expected) {
	close();
	}
	}
	}

	/**
	* Returns true if the mark is valid, false otherwise
	*/
	private boolean isMarked() {

	if (markLimit < 0) {
	return false;
	}

	// mark is set, but is not valid anymore
	if (count - markedCount > markLimit) {
	return false;
	}

	// mark still holds
	return true;
	}

	public synchronized int read() throws java.io.IOException {
	if (closed) {
	return -1;
	}
	int c = in.read();
	if (c != -1) {
	justRead(1);
	} else {
	justRead(c);
	}
	return c;
	}

	public synchronized int read(byte b[], int off, int len)
	throws java.io.IOException {
	if (closed) {
	return -1;
	}
	int n = in.read(b, off, len);
	justRead(n);
	return n;
	}

	public synchronized long skip(long n) throws IOException {

	// REMIND: what does skip do on EOF????
	if (closed) {
	return 0;
	}

	if (in instanceof ChunkedInputStream) {
	n = in.skip(n);
	}
	else {
	// just skip min(n, num_bytes_left)
	long min = (n > expected - count) ? expected - count: n;
	n = in.skip(min);
	}
	justRead(n);
	return n;
	}

	public void close() throws IOException {
	if (closed) {
	return;
	}
	if (pi != null)
	pi.finishTracking();

	closed = true;
	in.close();
	}

	public synchronized int available() throws IOException {
	return closed ? 0: in.available();
	}

	public synchronized void mark(int readLimit) {
	if (closed) {
	return;
	}
	super.mark(readLimit);

	/*
	* mark the count to restore upon reset
	*/
	markedCount = count;
	markLimit = readLimit;
	}

	public synchronized void reset() throws IOException {
	if (closed) {
	return;
	}

	if (!isMarked()) {
	throw new IOException ("Resetting to an invalid mark");
	}

	count = markedCount;
	super.reset();
	}

	public boolean markSupported() {
	if (closed) {
	return false;
	}
	return super.markSupported();
	}

	protected void finalize() throws Throwable {
	try {
	close();
	if (pi != null)
	pi.close();
	}
	finally {
	// Call super class
	super.finalize();
	}
	}
	}

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