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	/*
	* Copyright (c) 2001, 2003, 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 com.sun.jndi.ldap.sasl;

	import javax.security.sasl.Sasl;
	import javax.security.sasl.SaslClient;
	import javax.security.sasl.SaslException;
	import java.io.IOException;
	import java.io.EOFException;
	import java.io.InputStream;

	/**
	* This class is used by clients of Java SASL that need to create an input stream
	* that uses SaslClient's unwrap() method to decode the SASL buffers
	* sent by the SASL server.
	*
	* Extend from InputStream instead of FilterInputStream because
	* we need to override less methods in InputStream. That is, the
	* behavior of the default implementations in InputStream matches
	* more closely with the behavior we want in SaslInputStream.
	*
	* @author Rosanna Lee
	*/
	public class SaslInputStream extends InputStream {
	private static final boolean debug = false;

	private byte[] saslBuffer; // buffer for storing raw bytes
	private byte[] lenBuf = new byte[4]; // buffer for storing length

	private byte[] buf = new byte[0]; // buffer for storing processed bytes
	// Initialized to empty buffer
	private int bufPos = 0; // read position in buf
	private InputStream in; // underlying input stream
	private SaslClient sc;
	private int recvMaxBufSize = 65536;

	SaslInputStream(SaslClient sc, InputStream in) throws SaslException {
	super();
	this.in = in;
	this.sc = sc;

	String str = (String) sc.getNegotiatedProperty(Sasl.MAX_BUFFER);
	if (str != null) {
	try {
	recvMaxBufSize = Integer.parseInt(str);
	} catch (NumberFormatException e) {
	throw new SaslException(Sasl.MAX_BUFFER +
	" property must be numeric string: " + str);
	}
	}
	saslBuffer = new byte[recvMaxBufSize];
	}

	public int read() throws IOException {
	byte[] inBuf = new byte[1];
	int count = read(inBuf, 0, 1);
	if (count > 0) {
	return inBuf[0];
	} else {
	return -1;
	}
	}

	public int read(byte[] inBuf, int start, int count) throws IOException {

	if (bufPos >= buf.length) {
	int actual = fill(); // read and unwrap next SASL buffer
	while (actual == 0) { // ignore zero length content
	actual = fill();
	}
	if (actual == -1) {
	return -1; // EOF
	}
	}

	int avail = buf.length - bufPos;
	if (count > avail) {
	// Requesting more that we have stored
	// Return all that we have; next invocation of read() will
	// trigger fill()
	System.arraycopy(buf, bufPos, inBuf, start, avail);
	bufPos = buf.length;
	return avail;
	} else {
	// Requesting less than we have stored
	// Return all that was requested
	System.arraycopy(buf, bufPos, inBuf, start, count);
	bufPos += count;
	return count;
	}
	}

	/**
	* Fills the buf with more data by reading a SASL buffer, unwrapping it,
	* and leaving the bytes in buf for read() to return.
	* @return The number of unwrapped bytes available
	*/
	private int fill() throws IOException {
	// Read in length of buffer
	int actual = readFully(lenBuf, 4);
	if (actual != 4) {
	return -1;
	}
	int len = networkByteOrderToInt(lenBuf, 0, 4);

	if (len > recvMaxBufSize) {
	throw new IOException(
	len + "exceeds the negotiated receive buffer size limit:" +
	recvMaxBufSize);
	}

	if (debug) {
	System.err.println("reading " + len + " bytes from network");
	}

	// Read SASL buffer
	actual = readFully(saslBuffer, len);
	if (actual != len) {
	throw new EOFException("Expecting to read " + len +
	" bytes but got " + actual + " bytes before EOF");
	}

	// Unwrap
	buf = sc.unwrap(saslBuffer, 0, len);

	bufPos = 0;

	return buf.length;
	}

	/**
	* Read requested number of bytes before returning.
	* @return The number of bytes actually read; -1 if none read
	*/
	private int readFully(byte[] inBuf, int total) throws IOException {
	int count, pos = 0;

	if (debug) {
	System.err.println("readFully " + total + " from " + in);
	}

	while (total > 0) {
	count = in.read(inBuf, pos, total);

	if (debug) {
	System.err.println("readFully read " + count);
	}

	if (count == -1 ) {
	return (pos == 0? -1 : pos);
	}
	pos += count;
	total -= count;
	}
	return pos;
	}

	public int available() throws IOException {
	return buf.length - bufPos;
	}

	public void close() throws IOException {
	SaslException save = null;
	try {
	sc.dispose(); // Dispose of SaslClient's state
	} catch (SaslException e) {
	// Save exception for throwing after closing 'in'
	save = e;
	}

	in.close(); // Close underlying input stream

	if (save != null) {
	throw save;
	}
	}

	/**
	* Returns the integer represented by 4 bytes in network byte order.
	*/
	// Copied from com.sun.security.sasl.util.SaslImpl.
	private static int networkByteOrderToInt(byte[] buf, int start, int count) {
	if (count > 4) {
	throw new IllegalArgumentException("Cannot handle more than 4 bytes");
	}

	int answer = 0;

	for (int i = 0; i < count; i++) {
	answer <<= 8;
	answer \|= ((int)buf[start+i] & 0xff);
	}
	return answer;
	}
	}

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