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/*
* SaslInputStream.java
* Copyright (C) 2002 The Free Software Foundation
*
* This file is part of GNU inetlib, a library.
*
* GNU inetlib is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* GNU inetlib 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 for more details.
*
* You should have received a copy of the GNU General Public License
* along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Linking this library statically or dynamically with other modules is
* making a combined work based on this library. Thus, the terms and
* conditions of the GNU General Public License cover the whole
* combination.
*
* As a special exception, the copyright holders of this library give you
* permission to link this library with independent modules to produce an
* executable, regardless of the license terms of these independent
* modules, and to copy and distribute the resulting executable under
* terms of your choice, provided that you also meet, for each linked
* independent module, the terms and conditions of the license of that
* module. An independent module is a module which is not derived from
* or based on this library. If you modify this library, you may extend
* this exception to your version of the library, but you are not
* obliged to do so. If you do not wish to do so, delete this
* exception statement from your version.
*/
package gnu.inet.util;
import java.io.FilterInputStream;
import java.io.InputStream;
import java.io.IOException;
import javax.security.sasl.SaslClient;
/**
* A filter input stream that decodes all its received input using a SASL
* client.
*
* @author <a href="mailto:dog@gnu.org">Chris Burdess</a>
*/
public class SaslInputStream
extends FilterInputStream
{
/*
* The SASL client.
*/
private final SaslClient sasl;
/*
* Overflow buffer.
*/
private byte[] buf;
/*
* Offset in overflow buffer.
*/
private int pos;
/**
* Constructor.
* @param sasl the SASL client
* @param in the underlying input stream
*/
public SaslInputStream(SaslClient sasl, InputStream in)
{
super(in);
this.sasl = sasl;
}
/**
* Reads a single character.
*/
public int read()
throws IOException
{
if (buf != null)
{
// Return next characer in buffer
int c = (int) buf[pos++];
if (pos == buf.length)
{
buf = null;
}
return c;
}
int c = super.read();
if (c == -1)
{
return c;
}
byte[] bytes = new byte[1];
byte[] unwrapped = sasl.unwrap(bytes, 0, 1);
// FIXME if we get 0 bytes, we have a problem
c = (int) unwrapped[0];
if (unwrapped.length > 1)
{
// Store in overflow buffer
int l = unwrapped.length - 1;
buf = new byte[l];
System.arraycopy(unwrapped, 1, buf, 0, l);
pos = 0;
}
return c;
}
public int read(byte[] bytes)
throws IOException
{
return read(bytes, 0, bytes.length);
}
/**
* Block read.
*/
public int read(byte[] bytes, int off, int len)
throws IOException
{
if (buf != null)
{
// Return bytes from buffer
int l = buf.length;
if (l - pos <= len)
{
System.arraycopy(buf, pos, bytes, off, l);
buf = null;
return l;
}
else
{
System.arraycopy(buf, pos, bytes, off, len);
pos += len;
return len;
}
}
int l = super.read(bytes, off, len);
if (l == -1)
{
return l;
}
byte[] unwrapped = sasl.unwrap(bytes, off, l);
int l2 = unwrapped.length;
if (l2 > len)
{
// Store excess bytes in buffer
int d = l2 - len;
buf = new byte[d];
System.arraycopy(unwrapped, 0, bytes, off, len);
System.arraycopy(unwrapped, len, buf, 0, d);
pos = 0;
return len;
}
else
{
System.arraycopy(unwrapped, 0, bytes, off, l2);
// Zero bytes from l2..l to ensure none of the original
// bytes received can be read by the caller
for (int i = l2; i < l; i++)
{
bytes[off + l2] = 0;
}
return l2;
}
}
}
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