| /* 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. |
| |
| As a special exception, if you link this library with other files to |
| produce an executable, this library does not by itself cause the |
| resulting executable to be covered by the GNU General Public License. |
| This exception does not however invalidate any other reasons why the |
| executable file might be covered by the GNU General Public License. */ |
| |
| |
| 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); |
| |
| super.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); |
| |
| super.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(); |
| } |
| } |