001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements. See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership. The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License. You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied. See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 *
019 */
020 package org.apache.directory.server.kerberos.shared.io.decoder;
021
022
023 import java.util.Enumeration;
024
025 import org.apache.directory.server.kerberos.shared.crypto.checksum.ChecksumType;
026 import org.apache.directory.server.kerberos.shared.messages.value.Checksum;
027 import org.apache.directory.shared.asn1.der.DEREncodable;
028 import org.apache.directory.shared.asn1.der.DERInteger;
029 import org.apache.directory.shared.asn1.der.DEROctetString;
030 import org.apache.directory.shared.asn1.der.DERSequence;
031 import org.apache.directory.shared.asn1.der.DERTaggedObject;
032
033
034 /**
035 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
036 * @version $Rev: 588239 $, $Date: 2007-10-25 17:24:28 +0300 (Thu, 25 Oct 2007) $
037 */
038 public class ChecksumDecoder
039 {
040 /**
041 * Checksum ::= SEQUENCE {
042 * cksumtype[0] INTEGER,
043 * checksum[1] OCTET STRING
044 * }
045 * @param sequence
046 * @return The {@link Checksum}.
047 */
048 public static Checksum decode( DERSequence sequence )
049 {
050 ChecksumType type = ChecksumType.NULL;
051 byte[] data = null;
052
053 for ( Enumeration<DEREncodable> e = sequence.getObjects(); e.hasMoreElements(); )
054 {
055 DERTaggedObject object = ( DERTaggedObject ) e.nextElement();
056 int tag = object.getTagNo();
057 DEREncodable derObject = object.getObject();
058
059 switch ( tag )
060 {
061 case 0:
062 DERInteger tag0 = ( DERInteger ) derObject;
063 type = ChecksumType.getTypeByOrdinal( tag0.intValue() );
064 break;
065
066 case 1:
067 DEROctetString tag1 = ( DEROctetString ) derObject;
068 data = tag1.getOctets();
069 break;
070 }
071 }
072
073 return new Checksum( type, data );
074 }
075 }