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	/*
	* Copyright (c) 1996, 2011, 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.io;


	/**
	* A buffered character-input stream that keeps track of line numbers. This
	* class defines methods {@link #setLineNumber(int)} and {@link
	* #getLineNumber()} for setting and getting the current line number
	* respectively.
	*
	* <p> By default, line numbering begins at 0. This number increments at every
	* <a href="#lt">line terminator</a> as the data is read, and can be changed
	* with a call to {@code setLineNumber(int)}. Note however, that
	* {@code setLineNumber(int)} does not actually change the current position in
	* the stream; it only changes the value that will be returned by
	* {@code getLineNumber()}.
	*
	* <p> A line is considered to be <a id="lt">terminated</a> by any one of a
	* line feed ('\n'), a carriage return ('\r'), or a carriage return followed
	* immediately by a linefeed.
	*
	* @author Mark Reinhold
	* @since 1.1
	*/

	public class LineNumberReader extends BufferedReader {

	/** The current line number */
	private int lineNumber = 0;

	/** The line number of the mark, if any */
	private int markedLineNumber; // Defaults to 0

	/** If the next character is a line feed, skip it */
	private boolean skipLF;

	/** The skipLF flag when the mark was set */
	private boolean markedSkipLF;

	/**
	* Create a new line-numbering reader, using the default input-buffer
	* size.
	*
	* @param in
	* A Reader object to provide the underlying stream
	*/
	public LineNumberReader(Reader in) {
	super(in);
	}

	/**
	* Create a new line-numbering reader, reading characters into a buffer of
	* the given size.
	*
	* @param in
	* A Reader object to provide the underlying stream
	*
	* @param sz
	* An int specifying the size of the buffer
	*/
	public LineNumberReader(Reader in, int sz) {
	super(in, sz);
	}

	/**
	* Set the current line number.
	*
	* @param lineNumber
	* An int specifying the line number
	*
	* @see #getLineNumber
	*/
	public void setLineNumber(int lineNumber) {
	this.lineNumber = lineNumber;
	}

	/**
	* Get the current line number.
	*
	* @return The current line number
	*
	* @see #setLineNumber
	*/
	public int getLineNumber() {
	return lineNumber;
	}

	/**
	* Read a single character. <a href="#lt">Line terminators</a> are
	* compressed into single newline ('\n') characters. Whenever a line
	* terminator is read the current line number is incremented.
	*
	* @return The character read, or -1 if the end of the stream has been
	* reached
	*
	* @throws IOException
	* If an I/O error occurs
	*/
	@SuppressWarnings("fallthrough")
	public int read() throws IOException {
	synchronized (lock) {
	int c = super.read();
	if (skipLF) {
	if (c == '\n')
	c = super.read();
	skipLF = false;
	}
	switch (c) {
	case '\r':
	skipLF = true;
	case '\n': /* Fall through */
	lineNumber++;
	return '\n';
	}
	return c;
	}
	}

	/**
	* Read characters into a portion of an array. Whenever a <a
	* href="#lt">line terminator</a> is read the current line number is
	* incremented.
	*
	* @param cbuf
	* Destination buffer
	*
	* @param off
	* Offset at which to start storing characters
	*
	* @param len
	* Maximum number of characters to read
	*
	* @return The number of bytes read, or -1 if the end of the stream has
	* already been reached
	*
	* @throws IOException
	* If an I/O error occurs
	*
	* @throws IndexOutOfBoundsException {@inheritDoc}
	*/
	@SuppressWarnings("fallthrough")
	public int read(char cbuf[], int off, int len) throws IOException {
	synchronized (lock) {
	int n = super.read(cbuf, off, len);

	for (int i = off; i < off + n; i++) {
	int c = cbuf[i];
	if (skipLF) {
	skipLF = false;
	if (c == '\n')
	continue;
	}
	switch (c) {
	case '\r':
	skipLF = true;
	case '\n': /* Fall through */
	lineNumber++;
	break;
	}
	}

	return n;
	}
	}

	/**
	* Read a line of text. Whenever a <a href="#lt">line terminator</a> is
	* read the current line number is incremented.
	*
	* @return A String containing the contents of the line, not including
	* any <a href="#lt">line termination characters</a>, or
	* {@code null} if the end of the stream has been reached
	*
	* @throws IOException
	* If an I/O error occurs
	*/
	public String readLine() throws IOException {
	synchronized (lock) {
	String l = super.readLine(skipLF);
	skipLF = false;
	if (l != null)
	lineNumber++;
	return l;
	}
	}

	/** Maximum skip-buffer size */
	private static final int maxSkipBufferSize = 8192;

	/** Skip buffer, null until allocated */
	private char skipBuffer[] = null;

	/**
	* Skip characters.
	*
	* @param n
	* The number of characters to skip
	*
	* @return The number of characters actually skipped
	*
	* @throws IOException
	* If an I/O error occurs
	*
	* @throws IllegalArgumentException
	* If {@code n} is negative
	*/
	public long skip(long n) throws IOException {
	if (n < 0)
	throw new IllegalArgumentException("skip() value is negative");
	int nn = (int) Math.min(n, maxSkipBufferSize);
	synchronized (lock) {
	if ((skipBuffer == null) \|\| (skipBuffer.length < nn))
	skipBuffer = new char[nn];
	long r = n;
	while (r > 0) {
	int nc = read(skipBuffer, 0, (int) Math.min(r, nn));
	if (nc == -1)
	break;
	r -= nc;
	}
	return n - r;
	}
	}

	/**
	* Mark the present position in the stream. Subsequent calls to reset()
	* will attempt to reposition the stream to this point, and will also reset
	* the line number appropriately.
	*
	* @param readAheadLimit
	* Limit on the number of characters that may be read while still
	* preserving the mark. After reading this many characters,
	* attempting to reset the stream may fail.
	*
	* @throws IOException
	* If an I/O error occurs
	*/
	public void mark(int readAheadLimit) throws IOException {
	synchronized (lock) {
	super.mark(readAheadLimit);
	markedLineNumber = lineNumber;
	markedSkipLF = skipLF;
	}
	}

	/**
	* Reset the stream to the most recent mark.
	*
	* @throws IOException
	* If the stream has not been marked, or if the mark has been
	* invalidated
	*/
	public void reset() throws IOException {
	synchronized (lock) {
	super.reset();
	lineNumber = markedLineNumber;
	skipLF = markedSkipLF;
	}
	}

	}

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