| /* DigestOutputStream.java --- An output stream tied to a message digest |
| Copyright (C) 1999 Free Software Foundation, Inc. |
| |
| This file is 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, 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; see the file COPYING. 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 |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| package java.security; |
| |
| import java.io.OutputStream; |
| import java.io.FilterOutputStream; |
| import java.io.IOException; |
| |
| /** |
| DigestOutputStream is a class that ties an OutputStream with a |
| MessageDigest. The Message Digest is used by the class to update it |
| self as bytes are written to the OutputStream. |
| |
| The updating to the digest depends on the on flag which is set to |
| true by default that tells the class to update the data in the |
| message digest. |
| |
| @version 0.0 |
| @author Mark Benvenuto <ivymccough@worldnet.att.net> |
| */ |
| public class DigestOutputStream extends FilterOutputStream |
| { |
| /** |
| The message digest for the DigestOutputStream |
| */ |
| protected MessageDigest digest; |
| |
| //Manages the on flag |
| private boolean state = true; |
| |
| /** |
| Constructs a new DigestOutputStream. It associates a |
| MessageDigest with the stream to compute the stream as data is |
| written. |
| |
| @param stream An OutputStream to associate this stream with |
| @param digest A MessageDigest to hash the stream with |
| */ |
| public DigestOutputStream(OutputStream stream, MessageDigest digest) |
| { |
| super(stream); |
| this.digest = digest; |
| } |
| |
| /** |
| Returns the MessageDigest associated with this DigestOutputStream |
| |
| @return The MessageDigest used to hash this stream |
| */ |
| public MessageDigest getMessageDigest() |
| { |
| return digest; |
| } |
| |
| /** |
| Sets the current MessageDigest to current parameter |
| |
| @param digest A MessageDigest to associate with this stream |
| */ |
| public void setMessageDigest(MessageDigest digest) |
| { |
| this.digest = digest; |
| } |
| |
| |
| /** |
| Updates the hash if the on flag is true and then writes a byte to |
| the underlying output stream. |
| |
| @param b A byte to write to the output stream |
| |
| @exception IOException if the underlying output stream |
| cannot write the byte, this is thrown. |
| */ |
| public void write(int b) throws IOException |
| { |
| if (state) |
| digest.update((byte) b); |
| |
| out.write(b); |
| } |
| |
| /** |
| Updates the hash if the on flag is true and then writes the bytes |
| to the underlying output stream. |
| |
| @param b Bytes to write to the output stream |
| @param off Offset to start to start at in array |
| @param len Length of data to write |
| |
| @exception IOException if the underlying output stream |
| cannot write the bytes, this is thrown. |
| */ |
| public void write(byte[]b, int off, int len) throws IOException |
| { |
| if (state) |
| digest.update(b, off, len); |
| |
| out.write(b, off, len); |
| } |
| |
| /** |
| Sets the flag specifying if this DigestOutputStream updates the |
| digest in the write() methods. The default is on; |
| |
| @param on True means it digests stream, false means it does not |
| */ |
| public void on(boolean on) |
| { |
| state = on; |
| } |
| |
| /** |
| Converts the output stream and underlying message digest to a string. |
| |
| @return A string representing the output stream and message digest. |
| */ |
| public String toString() |
| { |
| return "[Digest Output Stream] " + digest.toString(); |
| } |
| } |