| /* DigestInputStream.java --- An Input stream tied to a message digest |
| Copyright (C) 1999, 2003, 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., 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.FilterInputStream; |
| import java.io.IOException; |
| import java.io.InputStream; |
| |
| /** |
| * DigestInputStream is a class that ties an InputStream with a |
| * MessageDigest. The Message Digest is used by the class to |
| * update it self as bytes are read from the InputStream. |
| * |
| * The updating to the digest depends on the on flag which is set |
| * to true by default to tell the class to update the data |
| * in the message digest. |
| * |
| * @version 0.0 |
| * @author Mark Benvenuto (ivymccough@worldnet.att.net) |
| */ |
| public class DigestInputStream extends FilterInputStream |
| { |
| /** |
| * The message digest for the DigestInputStream |
| */ |
| protected MessageDigest digest; |
| |
| //Manages the on flag |
| private boolean state = true; |
| |
| /** |
| * Constructs a new DigestInputStream. |
| * It associates a MessageDigest with the stream to |
| * compute the stream as data is written. |
| * |
| * @param stream An InputStream to associate this stream with |
| * @param digest A MessageDigest to hash the stream with |
| */ |
| public DigestInputStream(InputStream stream, MessageDigest digest) |
| { |
| super(stream); |
| //this.in = stream; |
| this.digest = digest; |
| } |
| |
| /** |
| * Returns the MessageDigest associated with this DigestInputStream |
| * |
| * @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; |
| } |
| |
| /** |
| * Reads a byte from the input stream and updates the digest. |
| * This method reads the underlying input stream and if the |
| * on flag is true then updates the message digest. |
| * |
| * @return Returns a byte from the input stream, -1 is returned to indicate that |
| * the end of stream was reached before this read call |
| * |
| * @throws IOException if an IO error occurs in the underlying input stream, |
| * this error is thrown |
| */ |
| public int read() throws IOException |
| { |
| int temp = in.read(); |
| |
| if (state == true && temp != -1) |
| digest.update((byte) temp); |
| |
| return temp; |
| } |
| |
| /** |
| * Reads bytes from the input stream and updates the digest. |
| * This method reads the underlying input stream and if the |
| * on flag is true then updates the message digest. |
| * |
| * @param b a byte array to store the data from the input stream |
| * @param off an offset to start at in the array |
| * @param len length of data to read |
| * @return Returns count of bytes read, -1 is returned to indicate that |
| * the end of stream was reached before this read call |
| * |
| * @throws IOException if an IO error occurs in the underlying input stream, |
| * this error is thrown |
| */ |
| public int read(byte[]b, int off, int len) throws IOException |
| { |
| int temp = in.read(b, off, len); |
| |
| if (state == true && temp != -1) |
| digest.update(b, off, temp); |
| |
| return temp; |
| } |
| |
| /** |
| * Sets the flag specifing if this DigestInputStream 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 input stream and underlying message digest to a string. |
| * |
| * @return A string representing the input stream and message digest. |
| */ |
| public String toString() |
| { |
| return "[Digest Input Stream] " + digest.toString(); |
| } |
| } |