source: other-projects/trunk/gs3-release-maker/tasks/sshtaskdef/src/mindbright/security/MessageDigest.java@ 14627

/******************************************************************************
 *
 * Copyright (c) 1998-2000 by Mindbright Technology AB, Stockholm, Sweden.
 *                 www.mindbright.se, [email protected]
 *
 * This program 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 of the License, or
 * (at your option) any later version.
 *
 * 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.
 *
 *****************************************************************************
 * $Author: mats $
 * $Date: 2000/05/16 10:30:42 $
 * $Name: rel1-2-1 $
 *****************************************************************************/
package mindbright.security;

public abstract class MessageDigest {
    public static boolean useNative = false;

    public static MessageDigest getInstance(String algorithm)
    throws InstantiationException, IllegalAccessException, ClassNotFoundException
    {
    if(useNative) {
        try {
        Class c1, c2;
        c1 = Class.forName("java.security.MessageDigest");
        c2 = Class.forName("mindbright.security.NativeHashState");
        MessageDigest md = (MessageDigest)c2.newInstance();
        md.init(algorithm);
        return md;
        } catch (Throwable t) {
        // !!! Oh well, we're not too worried, the pure java
        // versions are pretty quick, we don't need no
        // steenking native code anyway... :-)
        }
    }
    Class c;
    c = Class.forName("mindbright.security." + algorithm);
    return (MessageDigest)c.newInstance();
    }

    protected void init(String algorithm) throws Exception {
    }

    public abstract String getName();
    public abstract void reset();
    public abstract void update(byte[] buf, int offset, int length);
    public abstract byte[] digest();
    public abstract int blockSize();
    public abstract int hashSize();

    public final void update(byte[] buf) {
        update(buf, 0, buf.length);
    }

    public int digestInto(byte[] dest, int destOff) {
    byte[] dig = digest();
    System.arraycopy(dig, 0, dest, destOff, dig.length);
    return dig.length;
    }

    public Object clone() throws CloneNotSupportedException {
    if(this instanceof Cloneable) {
        return super.clone();
    } else {
        throw new CloneNotSupportedException();
    }
    }
}