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diff --git a/java/security/MessageDigestSpi.java b/java/security/MessageDigestSpi.java
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+/* MessageDigestSpi.java --- The message digest service provider interface.

+   

+  Copyright (c) 1999 by Free Software Foundation, Inc.

+  Written by Mark Benvenuto <ivymccough@worldnet.att.net>

+

+  This program is free software; you can redistribute it and/or modify

+  it under the terms of the GNU Library General Public License as published 

+  by the Free Software Foundation, version 2. (see COPYING.LIB)

+

+  This program 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 this program; if not, write to the Free Software Foundation

+  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307 USA. */

+

+package java.security;

+

+/**

+   This is the Service Provider Interface (SPI) for MessageDigest

+   class in java.security. It provides the back end functionality

+   for the MessageDigest class so that it can compute message 

+   hashes. The default hashes are SHA-1 and MD5. A message hash

+   takes data of arbitrary length and produces a unique number

+   representing it. 

+

+   Cryptography service providers who want to implement their

+   own message digest hashes need only to subclass this class.

+

+   The implementation of a Cloneable interface is left to up to 

+   the programmer of a subclass.

+	

+   @version 0.0

+  

+   @author Mark Benvenuto <ivymccough@worldnet.att.net>

+*/

+

+public abstract class MessageDigestSpi

+{

+  /**

+     Default constructor of the MessageDigestSpi class

+  */

+  public MessageDigestSpi () {}

+

+  /**

+     Returns the length of the digest.  It may be overridden by the

+     provider to return the length of the digest.  Default is to

+     return 0.  It is concrete for backwards compatibility with JDK1.1

+     message digest classes.

+

+     @return Length of Digest in Bytes

+     

+     @since 1.2

+  */

+  protected int engineGetDigestLength ()

+  {

+    return 0;

+  }

+

+  /**

+     Updates the digest with the specified byte.

+

+     @param input the byte to update digest with

+  */

+  protected abstract void engineUpdate (byte input);

+

+

+  /**

+     Updates the digest with the specified bytes starting with the

+     offset and proceeding for the specified length.

+

+     @param input the byte array to update digest with

+     @param offset the offset of the byte to start with

+     @param len the number of the bytes to update with

+  */

+  protected abstract void engineUpdate (byte[] input, int offset, int len);

+

+  /**

+     Computes the final digest of the stored bytes and returns

+     them. It performs any necessary padding. The message digest

+     should reset sensitive data after performing the digest.

+

+     @return An array of bytes containing the digest

+  */

+  protected abstract byte[] engineDigest();

+

+  /**

+     Computes the final digest of the stored bytes and returns

+     them. It performs any necessary padding. The message digest

+     should reset sensitive data after performing the digest.  This

+     method is left concrete for backwards compatibility with JDK1.1

+     message digest classes.

+

+     @param buf An array of bytes to store the digest

+     @param offset An offset to start storing the digest at

+     @param len The length of the buffer

+     @return Returns the length of the buffer

+

+     @since 1.2

+  */

+  protected int engineDigest (byte[] buf, int offset, int len)

+    throws DigestException

+  {

+    if ( engineGetDigestLength () > len)

+      throw new DigestException ("Buffer is too small.");

+

+    byte tmp[] = engineDigest ();

+    if (tmp.length > len)

+      throw new DigestException ("Buffer is too small");

+

+    System.arraycopy (tmp, 0, buf, offset, tmp.length);

+    return tmp.length;

+  }

+

+  /**

+     Resets the digest engine. Reinitializes internal variables 

+     and clears sensitive data.

+  */

+  protected abstract void engineReset ();

+

+  /**

+     Returns a clone of this class.

+

+     If cloning is not supported, then by default the class throws a

+     CloneNotSupportedException.  The MessageDigestSpi provider

+     implementation has to overload this class in order to be

+     cloneable.

+  */

+  public Object clone () throws CloneNotSupportedException

+  {

+    if (this instanceof Cloneable)

+      return super.clone ();

+    else

+      throw new CloneNotSupportedException ();

+  }

+

+}