| /* MacOutputStream.java -- |
| Copyright (C) 2003, 2006 Free Software Foundation, Inc. |
| |
| This file is a part of GNU Classpath. |
| |
| GNU Classpath 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 Classpath 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 GNU Classpath; if not, write to the Free Software |
| Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 |
| 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 |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package gnu.javax.crypto.mac; |
| |
| import java.io.FilterOutputStream; |
| import java.io.IOException; |
| import java.io.OutputStream; |
| |
| /** |
| * A filtering output stream that computes a MAC (message authentication code) |
| * over all data written to the stream. |
| */ |
| public class MacOutputStream |
| extends FilterOutputStream |
| { |
| /** The digesting state. The MAC is updated only if this flag is true. */ |
| private boolean digesting; |
| /** The MAC being updated. */ |
| private IMac mac; |
| |
| /** |
| * Creates a new <code>MacOutputStream</code>. The stream is initially set |
| * to digest data written, the <code>mac</code> argument must have already |
| * been initialized, and the <code>mac</code> argument is <b>not</b> |
| * cloned. |
| * |
| * @param out The underlying output stream. |
| * @param mac The mac instance to use. |
| */ |
| public MacOutputStream(OutputStream out, IMac mac) |
| { |
| super(out); |
| if (mac == null) |
| throw new NullPointerException(); |
| this.mac = mac; |
| digesting = true; |
| } |
| |
| /** |
| * Returns the MAC this stream is updating. |
| * |
| * @return The MAC. |
| */ |
| public IMac getMac() |
| { |
| return mac; |
| } |
| |
| /** |
| * Sets the MAC this stream is updating, which must have already been |
| * initialized. The argument is not cloned by this method. |
| * |
| * @param mac The non-null new MAC. |
| * @throws NullPointerException If the argument is null. |
| */ |
| public void setMac(IMac mac) |
| { |
| if (mac == null) |
| throw new NullPointerException(); |
| this.mac = mac; |
| } |
| |
| /** |
| * Turns the digesting state on or off. When off, the MAC will not be updated |
| * when data is written to the stream. |
| * |
| * @param flag The new digesting state. |
| */ |
| public void on(boolean flag) |
| { |
| digesting = flag; |
| } |
| |
| public void write(int b) throws IOException |
| { |
| if (digesting) |
| mac.update((byte) b); |
| out.write(b); |
| } |
| |
| public void write(byte[] buf, int off, int len) throws IOException |
| { |
| if (digesting) |
| mac.update(buf, off, len); |
| out.write(buf, off, len); |
| } |
| } |