derdecoder.java

JAVA的加密库之一

	}

	// ASN1InputStream abstract methods implementation
	// ........................................................................

	/**
	 * Initialises this instance to decode from the designated input stream.
	 *
	 * @param is the designated input stream to decode.
	 * @exception IllegalStateException if this instance is already initialised
	 * with an input stream. Caller should close the previous stream before
	 * invoking this method again on a new input stream.
	 */
	public void open(InputStream is) {
		if (in != null)
      		throw new IllegalStateException();

		this.in = is instanceof BufferedInputStream
      		? (BufferedInputStream) is
            : new BufferedInputStream(is, 10240);
	}

	/**
	 * Decodes an ANY from the input stream.
	 *
	 * @param name the optional user-defined ASN.1 type name.
	 * @return the concrete object decoded from the underlying input stream.
	 * @exception DerObjectTooLargeException if the DER value of the length part
	 * exceeds 32-bit.
	 * @exception EOFException if the end-of-stream was encountered while
	 * decoding the element.
	 * @exception IOException if any other I/O related exception has occured.
	 */
	public IType decodeAny(String name) throws IOException {
		cat.debug("==> decodeAny("+name+")");

		Tag tag = null;
		try {
			tag = readTag();
		} catch (EOFException x) {
			throw new ElementNotFoundException("???");
		}

		int length = readLength();
		byte[] buffer = new byte[length];
		int actualLength = read(buffer);
		if (actualLength == -1)
			throw new EOFException();

		if (actualLength != length)
			throw new DerLengthMismatchException(actualLength, length);

		IType result = null;
		ArrayList values;
		DerDecoder local;
		if (tag.getClazz() == Tag.UNIVERSAL)
			switch (tag.getValue()) {
			case Tag.BOOLEAN:
				result = new ASNBoolean(name, tag, toBoolean(buffer));
				break;
			case Tag.INTEGER:
				result = new ASNInteger(name, tag, new BigInteger(1, buffer));
				break;
			case Tag.BIT_STRING:
				result = new BitString(name, tag, buffer);
				break;
			case Tag.OCTET_STRING:
				result = new OctetString(name, tag, buffer);
				break;
			case Tag.NULL:
				toNull(buffer); // throws an exception if malformed
				result = new Null(name, tag, new Object());
				break;
			case Tag.OBJECT_IDENTIFIER:
				result = new ObjectIdentifier(name, tag, toOID(buffer));
				break;
			case Tag.NUMERIC_STRING:
				result = new NumericString(name, tag, new String(buffer, "ASCII"));
				break;
			case Tag.PRINTABLE_STRING:
				result = new PrintableString(name, tag, new String(buffer, "ASCII"));
				break;
			case Tag.T61_STRING:
				result = new TeletexString(name, tag, new String(buffer, "ASCII"));
				break;
			case Tag.VIDEOTEX_STRING:
				result = new VideotexString(name, tag, new String(buffer, "ASCII"));
				break;
			case Tag.IA5_STRING:
				result = new IA5String(name, tag, new String(buffer, "ASCII"));
				break;
			case Tag.GRAPHIC_STRING:
				result = new GraphicString(name, tag, new String(buffer, "UTF8"));
				break;
			case Tag.ISO646_STRING:
				result = new VisibleString(name, tag, new String(buffer, "UTF8"));
				break;
			case Tag.GENERAL_STRING:
				result = new GeneralString(name, tag, new String(buffer, "UTF8"));
				break;
			case Tag.UNIVERSAL_STRING:
				result = new UniversalString(name, tag, new String(buffer, "UTF8"));
				break;
			case Tag.BMP_STRING:
				result = new BMPString(name, tag, new String(buffer, "UTF8"));
				break;
			case Tag.UTC_TIME:
				result = new UTCTime(name, tag, toDate(buffer));
				break;
			case Tag.GENERALIZED_TIME:
				result = new GeneralizedTime(name, tag, toFullDate(buffer));
				break;
			case Tag.SEQUENCE:
//			case Tag.SEQUENCE_OF:
			case Tag.SET:
//			case Tag.SET_OF:
				values = new ArrayList();
				local = new DerDecoder(buffer);
				try {
					while (true)
						values.add(local.decodeAny("seq"));
				} catch (IOException ignored) {
				}

				result = new Any(name, tag, values);
				break;
			default:
			   cat.warn("Unable to parse an ANY; tag="+String.valueOf(tag));
				result = new Any(name, tag, buffer);
			}
		else if (tag.getClazz() == Tag.CONTEXT) {
		   if (tag.isExplicit()) {
		      // buffer contains a DER triplet (TLV)
      		DerDecoder embedded = new DerDecoder(buffer);
      		result = new Any(name, tag, embedded.decodeAny("xxx"));
//      		result = new Any(name, tag, embedded.decodeAny("xxx").getValue());
		   } else {
		      // buffer contains a DER value as a byte[]
		      result = new Any(name, tag, buffer);
		   }
		} else
			result = new Any(name, tag, buffer);

		cat.debug("<== decodeAny() --> "+result);
		return result;
	}

	/**
	 * Decodes an OBJECT IDENTIFIER from the input stream.
	 *
	 * @param obj the element to decode.
	 * @return a String representation of the OID decoded from the stream.
	 * @exception TagMismatchException if the element in the stream has a
	 * different tag to the designated one.
	 * @exception DerObjectTooLargeException if the DER value of the length part
	 * exceeds 32-bit.
	 * @exception EOFException if the end-of-stream was encountered while
	 * decoding the element.
	 * @exception IOException if any other I/O related exception has occured.
	 */
	public String decodeObjectIdentifier(IType obj) throws IOException {
		cat.debug("==> decodeObjectIdentifier()");

		Tag tag = obj.tag();
		byte[] buffer = readRaw(tag, Tag.OBJECT_IDENTIFIER);
		String result = toOID(buffer);

		cat.debug("<== decodeObjectIdentifier() --> "+result);
		return result;
	}

	/**
	 * Decodes a NULL from the input stream.
	 *
	 * @param obj the element to decode.
	 * @exception TagMismatchException if the element in the stream has a
	 * different tag to the designated one.
	 * @exception DerObjectTooLargeException if the DER value of the length part
	 * exceeds 32-bit.
	 * @exception DerInvalidLengthException if a mismatch between the expected
	 * and parsed size of the element's encoding is detected.
	 * @exception EOFException if the end-of-stream was encountered while
	 * decoding the element.
	 * @exception IOException if any other I/O related exception has occured.
	 */
	public void decodeNull(IType obj) throws IOException {
		cat.debug("==> decodeNull()");

		Tag tag = obj.tag();
		byte[] buffer = readRaw(tag, Tag.NULL);
		toNull(buffer);

		cat.debug("<== decodeNull()");
	}

	/**
	 * Decodes a BOOLEAN from the input stream.
	 *
	 * @param obj the element to decode.
	 * @return the concrete value of this ASN.1 type.
	 * @exception TagMismatchException if the element in the stream has a
	 * different tag to the designated one.
	 * @exception DerObjectTooLargeException if the DER value of the length part
	 * exceeds 32-bit.
	 * @exception DerInvalidLengthException if a mismatch between the expected
	 * and parsed size of the element's encoding is detected.
	 * @exception EOFException if the end-of-stream was encountered while
	 * decoding the element.
	 * @exception IOException if any other I/O related exception has occured.
	 */
	public Boolean decodeBoolean(IType obj) throws IOException {
		cat.debug("==> decodeBoolean()");

		Tag tag = obj.tag();
		byte[] buffer = readRaw(tag, Tag.BOOLEAN);
		Boolean result = toBoolean(buffer);

		cat.debug("<== decodeBoolean() --> "+result);
		return result;
	}

	/**
	 * Decodes an INTEGER from the input stream.
	 *
	 * @param obj the element to decode.
	 * @return the concrete value of this ASN.1 type.
	 * @exception TagMismatchException if the element in the stream has a
	 * different tag to the designated one.
	 * @exception DerObjectTooLargeException if the DER value of the length part
	 * exceeds 32-bit.
	 * @exception DerInvalidLengthException if a mismatch between the expected
	 * and parsed size of the element's encoding is detected.
	 * @exception EOFException if the end-of-stream was encountered while
	 * decoding the element.
	 * @exception IOException if any other I/O related exception has occured.
	 */
	public BigInteger decodeInteger(IType obj) throws IOException {
		cat.debug("==> decodeInteger()");

		Tag tag = obj.tag();
		byte[] buffer = readRaw(tag, Tag.INTEGER);
		BigInteger result = new BigInteger(1, buffer);

		cat.debug("<== decodeInteger() --> "+result);
		return result;
	}

	/**
	 * Decodes a PrintableString from the input stream.
	 *
	 * @param tagValue the value of a Tag constant to differentiate between
	 * the different types of strings.
	 * @param obj the element to decode.
	 * @return the concrete value of this ASN.1 type.
	 * @exception TagMismatchException if the element in the stream has a
	 * different tag to the designated one.
	 * @exception DerObjectTooLargeException if the DER value of the length part
	 * exceeds 32-bit.
	 * @exception DerInvalidLengthException if a mismatch between the expected
	 * and parsed size of the element's encoding is detected.
	 * @exception EOFException if the end-of-stream was encountered while
	 * decoding the element.
	 * @exception IOException if any other I/O related exception has occured.
	 */
	public String decodeString(int tagValue, IType obj) throws IOException {
		cat.debug("==> decodeString("+tagValue+")");

		Tag tag = obj.tag();
		byte[] buffer = readRaw(tag, tagValue);
		String result = new String(buffer, "UTF8");

		cat.debug("<== decodeString() --> \""+result+"\"");
		return result;
	}

	/**
	 * Decodes a BIT STRING from the input stream.
	 *
	 * @param obj the element to decode.
	 * @return the concrete value of this ASN.1 type.
	 * @exception TagMismatchException if the element in the stream has a
	 * different tag to the designated one.
	 * @exception DerObjectTooLargeException if the DER value of the length part
	 * exceeds 32-bit.
	 * @exception DerInvalidLengthException if a mismatch between the expected
	 * and parsed size of the element's encoding is detected.
	 * @exception EOFException if the end-of-stream was encountered while
	 * decoding the element.
	 * @exception IOException if any other I/O related exception has occured.
	 */
	public byte[] decodeBitString(IType obj) throws IOException {
		cat.debug("==> decodeBitString()");

		Tag tag = obj.tag();
		byte[] tmp = readRaw(tag, Tag.BIT_STRING);
		cat.warn("Truncating "+String.valueOf(tmp[0])+" unused leftmost bit(s) from a BIT STRING");
		byte[] result = new byte[tmp.length-1];
		System.arraycopy(tmp, 1, result, 0, result.length);

		cat.debug("<== decodeBitString() --> 0x"+(new BigInteger(1, result).toString(16)));
		return result;
	}

	/**
	 * Decodes an OCTET STRING from the input stream.
	 *
	 * @param obj the element to decode.
	 * @return the concrete value of this ASN.1 type.
	 * @exception TagMismatchException if the element in the stream has a
	 * different tag to the designated one.
	 * @exception DerObjectTooLargeException if the DER value of the length part
	 * exceeds 32-bit.
	 * @exception DerInvalidLengthException if a mismatch between the expected
	 * and parsed size of the element's encoding is detected.
	 * @exception EOFException if the end-of-stream was encountered while
	 * decoding the element.
	 * @exception IOException if any other I/O related exception has occured.
	 */
	public byte[] decodeOctetString(IType obj) throws IOException {
		cat.debug("==> decodeOctetString()");

		Tag tag = obj.tag();
		byte[] result = readRaw(tag, Tag.OCTET_STRING);

		cat.debug("<== decodeOctetString() --> 0x"+(new BigInteger(1, result).toString(16)));
		return result;
	}