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	/*
	* Copyright (c) 1995, 2018, 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.net;

	import java.io.FileDescriptor;
	import java.io.FileInputStream;
	import java.io.IOException;
	import java.nio.channels.FileChannel;

	import sun.net.ConnectionResetException;

	/**
	* This stream extends FileInputStream to implement a
	* SocketInputStream. Note that this class should <b>NOT</b> be
	* public.
	*
	* @author Jonathan Payne
	* @author Arthur van Hoff
	*/
	class SocketInputStream extends FileInputStream {
	static {
	init();
	}

	private boolean eof;
	private AbstractPlainSocketImpl impl = null;
	private byte temp[];
	private Socket socket = null;

	/**
	* Creates a new SocketInputStream. Can only be called
	* by a Socket. This method needs to hang on to the owner Socket so
	* that the fd will not be closed.
	* @param impl the implemented socket input stream
	*/
	SocketInputStream(AbstractPlainSocketImpl impl) throws IOException {
	super(impl.getFileDescriptor());
	this.impl = impl;
	socket = impl.getSocket();
	}

	/**
	* Returns the unique {@link java.nio.channels.FileChannel FileChannel}
	* object associated with this file input stream.</p>
	*
	* The {@code getChannel} method of {@code SocketInputStream}
	* returns {@code null} since it is a socket based stream.</p>
	*
	* @return the file channel associated with this file input stream
	*
	* @since 1.4
	* @spec JSR-51
	*/
	public final FileChannel getChannel() {
	return null;
	}

	/**
	* Reads into an array of bytes at the specified offset using
	* the received socket primitive.
	* @param fd the FileDescriptor
	* @param b the buffer into which the data is read
	* @param off the start offset of the data
	* @param len the maximum number of bytes read
	* @param timeout the read timeout in ms
	* @return the actual number of bytes read, -1 is
	* returned when the end of the stream is reached.
	* @exception IOException If an I/O error has occurred.
	*/
	private native int socketRead0(FileDescriptor fd,
	byte b[], int off, int len,
	int timeout)
	throws IOException;

	// wrap native call to allow instrumentation
	/**
	* Reads into an array of bytes at the specified offset using
	* the received socket primitive.
	* @param fd the FileDescriptor
	* @param b the buffer into which the data is read
	* @param off the start offset of the data
	* @param len the maximum number of bytes read
	* @param timeout the read timeout in ms
	* @return the actual number of bytes read, -1 is
	* returned when the end of the stream is reached.
	* @exception IOException If an I/O error has occurred.
	*/
	private int socketRead(FileDescriptor fd,
	byte b[], int off, int len,
	int timeout)
	throws IOException {
	return socketRead0(fd, b, off, len, timeout);
	}

	/**
	* Reads into a byte array data from the socket.
	* @param b the buffer into which the data is read
	* @return the actual number of bytes read, -1 is
	* returned when the end of the stream is reached.
	* @exception IOException If an I/O error has occurred.
	*/
	public int read(byte b[]) throws IOException {
	return read(b, 0, b.length);
	}

	/**
	* Reads into a byte array <i>b</i> at offset <i>off</i>,
	* <i>length</i> bytes of data.
	* @param b the buffer into which the data is read
	* @param off the start offset of the data
	* @param length the maximum number of bytes read
	* @return the actual number of bytes read, -1 is
	* returned when the end of the stream is reached.
	* @exception IOException If an I/O error has occurred.
	*/
	public int read(byte b[], int off, int length) throws IOException {
	return read(b, off, length, impl.getTimeout());
	}

	int read(byte b[], int off, int length, int timeout) throws IOException {
	int n;

	// EOF already encountered
	if (eof) {
	return -1;
	}

	// connection reset
	if (impl.isConnectionReset()) {
	throw new SocketException("Connection reset");
	}

	// bounds check
	if (length <= 0 \|\| off < 0 \|\| length > b.length - off) {
	if (length == 0) {
	return 0;
	}
	throw new ArrayIndexOutOfBoundsException("length == " + length
	+ " off == " + off + " buffer length == " + b.length);
	}

	// acquire file descriptor and do the read
	FileDescriptor fd = impl.acquireFD();
	try {
	n = socketRead(fd, b, off, length, timeout);
	if (n > 0) {
	return n;
	}
	} catch (ConnectionResetException rstExc) {
	impl.setConnectionReset();
	} finally {
	impl.releaseFD();
	}

	/*
	* If we get here we are at EOF, the socket has been closed,
	* or the connection has been reset.
	*/
	if (impl.isClosedOrPending()) {
	throw new SocketException("Socket closed");
	}
	if (impl.isConnectionReset()) {
	throw new SocketException("Connection reset");
	}
	eof = true;
	return -1;
	}

	/**
	* Reads a single byte from the socket.
	*/
	public int read() throws IOException {
	if (eof) {
	return -1;
	}
	temp = new byte[1];
	int n = read(temp, 0, 1);
	if (n <= 0) {
	return -1;
	}
	return temp[0] & 0xff;
	}

	/**
	* Skips n bytes of input.
	* @param numbytes the number of bytes to skip
	* @return the actual number of bytes skipped.
	* @exception IOException If an I/O error has occurred.
	*/
	public long skip(long numbytes) throws IOException {
	if (numbytes <= 0) {
	return 0;
	}
	long n = numbytes;
	int buflen = (int) Math.min(1024, n);
	byte data[] = new byte[buflen];
	while (n > 0) {
	int r = read(data, 0, (int) Math.min((long) buflen, n));
	if (r < 0) {
	break;
	}
	n -= r;
	}
	return numbytes - n;
	}

	/**
	* Returns the number of bytes that can be read without blocking.
	* @return the number of immediately available bytes
	*/
	public int available() throws IOException {
	return impl.available();
	}

	/**
	* Closes the stream.
	*/
	private boolean closing = false;
	public void close() throws IOException {
	// Prevent recursion. See BugId 4484411
	if (closing)
	return;
	closing = true;
	if (socket != null) {
	if (!socket.isClosed())
	socket.close();
	} else
	impl.close();
	closing = false;
	}

	void setEOF(boolean eof) {
	this.eof = eof;
	}

	/**
	* Overrides finalize, the fd is closed by the Socket.
	*/
	@SuppressWarnings({"deprecation", "removal"})
	protected void finalize() {}

	/**
	* Perform class load-time initializations.
	*/
	private static native void init();
	}

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