/** * Constructs an instance of Checksum from an ASN.1 encoded representation. * * @param encoding a single DER-encoded value. * @exception Asn1Exception if an error occurs while decoding an ASN1 encoded data. * @exception IOException if an I/O error occurs while reading encoded data. */ private Checksum(DerValue encoding) throws Asn1Exception, IOException { DerValue der; if (encoding.getTag() != DerValue.tag_Sequence) { throw new Asn1Exception(Krb5.ASN1_BAD_ID); } der = encoding.getData().getDerValue(); if ((der.getTag() & (byte) 0x1F) == (byte) 0x00) { cksumType = der.getData().getBigInteger().intValue(); } else throw new Asn1Exception(Krb5.ASN1_BAD_ID); der = encoding.getData().getDerValue(); if ((der.getTag() & (byte) 0x1F) == (byte) 0x01) { checksum = der.getData().getOctetString(); } else throw new Asn1Exception(Krb5.ASN1_BAD_ID); if (encoding.getData().available() > 0) { throw new Asn1Exception(Krb5.ASN1_BAD_ID); } }
/** * Parse (unmarshal) a checksum object from a DER input stream. This form parsing might be used * when expanding a value which is part of a constructed sequence and uses explicitly tagged type. * * @exception Asn1Exception if an error occurs while decoding an ASN1 encoded data. * @exception IOException if an I/O error occurs while reading encoded data. * @param data the Der input stream value, which contains one or more marshaled value. * @param explicitTag tag number. * @param optional indicates if this data field is optional * @return an instance of Checksum. */ public static Checksum parse(DerInputStream data, byte explicitTag, boolean optional) throws Asn1Exception, IOException { if ((optional) && (((byte) data.peekByte() & (byte) 0x1F) != explicitTag)) { return null; } DerValue der = data.getDerValue(); if (explicitTag != (der.getTag() & (byte) 0x1F)) { throw new Asn1Exception(Krb5.ASN1_BAD_ID); } else { DerValue subDer = der.getData().getDerValue(); return new Checksum(subDer); } }