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Diffstat (limited to 'libjava/classpath/java/security/DigestOutputStream.java')
-rw-r--r-- | libjava/classpath/java/security/DigestOutputStream.java | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/libjava/classpath/java/security/DigestOutputStream.java b/libjava/classpath/java/security/DigestOutputStream.java new file mode 100644 index 0000000..037b39e --- /dev/null +++ b/libjava/classpath/java/security/DigestOutputStream.java @@ -0,0 +1,158 @@ +/* DigestOutputStream.java --- An output stream tied to a message digest + Copyright (C) 1999, 2004, 2005 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., 51 Franklin Street, 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 java.security; + +import java.io.FilterOutputStream; +import java.io.IOException; +import java.io.OutputStream; + +/** + * 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(); + } +} |