package gnu.crypto.hash;
// ----------------------------------------------------------------------------
// $Id: HashFactory.java,v 1.14 2005/10/06 04:24:14 rsdio Exp $
//
// Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc.
//
// This file is part of GNU Crypto.
//
// GNU Crypto 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 Crypto 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; 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.
// ----------------------------------------------------------------------------
import gnu.crypto.Registry;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;
/**
* <p>A <i>Factory</i> to instantiate message digest algorithm instances.</p>
*
* @version $Revision: 1.14 $
*/
public class HashFactory {
// Constants and variables
// -------------------------------------------------------------------------
// Constructor(s)
// -------------------------------------------------------------------------
/** Trivial constructor to enforce <i>Singleton</i> pattern. */
private HashFactory() {
super();
}
// Class methods
// -------------------------------------------------------------------------
/**
* <p>Return an instance of a hash algorithm given its name.</p>
*
* @param name the name of the hash algorithm.
* @return an instance of the hash algorithm, or null if none found.
* @exception InternalError if the implementation does not pass its self-
* test.
*/
public static IMessageDigest getInstance(String name) {
if (name == null) {
return null;
}
name = name.trim();
IMessageDigest result = null;
if (name.equalsIgnoreCase(Registry.WHIRLPOOL_HASH)) {
result = new Whirlpool();
} else if (name.equalsIgnoreCase(Registry.RIPEMD128_HASH)
|| name.equalsIgnoreCase(Registry.RIPEMD_128_HASH)) {
result = new RipeMD128();
} else if (name.equalsIgnoreCase(Registry.RIPEMD160_HASH)
|| name.equalsIgnoreCase(Registry.RIPEMD_160_HASH)) {
result = new RipeMD160();
} else if (name.equalsIgnoreCase(Registry.SHA160_HASH)
|| name.equalsIgnoreCase(Registry.SHA_1_HASH)
|| name.equalsIgnoreCase(Registry.SHA1_HASH)
|| name.equalsIgnoreCase(Registry.SHA_HASH)) {
result = new Sha160();
} else if (name.equalsIgnoreCase(Registry.SHA256_HASH)) {
result = new Sha256();
} else if (name.equalsIgnoreCase(Registry.SHA384_HASH)) {
result = new Sha384();
} else if (name.equalsIgnoreCase(Registry.SHA512_HASH)) {
result = new Sha512();
} else if (name.equalsIgnoreCase(Registry.TIGER_HASH)) {
result = new Tiger();
} else if (name.equalsIgnoreCase(Registry.HAVAL_HASH)) {
result = new Haval();
} else if (name.equalsIgnoreCase(Registry.MD5_HASH)) {
result = new MD5();
} else if (name.equalsIgnoreCase(Registry.MD4_HASH)) {
result = new MD4();
} else if (name.equalsIgnoreCase(Registry.MD2_HASH)) {
result = new MD2();
} else if (name.equalsIgnoreCase(Registry.HAVAL_HASH)) {
result = new Haval();
}
if (result != null && !result.selfTest()) {
throw new InternalError(result.name());
}
return result;
}
/**
* <p>Returns a {@link Set} of names of hash algorithms supported by this
* <i>Factory</i>.</p>
*
* @return a {@link Set} of hash names (Strings).
*/
public static final Set getNames() {
HashSet hs = new HashSet();
hs.add(Registry.WHIRLPOOL_HASH);
hs.add(Registry.RIPEMD128_HASH);
hs.add(Registry.RIPEMD160_HASH);
hs.add(Registry.SHA160_HASH);
hs.add(Registry.SHA256_HASH);
hs.add(Registry.SHA384_HASH);
hs.add(Registry.SHA512_HASH);
hs.add(Registry.TIGER_HASH);
hs.add(Registry.HAVAL_HASH);
hs.add(Registry.MD5_HASH);
hs.add(Registry.MD4_HASH);
hs.add(Registry.MD2_HASH);
return Collections.unmodifiableSet(hs);
}
// Instance methods
// -------------------------------------------------------------------------
}