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DSS Model contains the data model representation for DSS
There is a newer version: 6.0.d4j.2
package port.org.bouncycastle.asn1;

import java.io.IOException;
import java.math.BigInteger;

import port.org.bouncycastle.util.Arrays;

/**
 * Class representing the ASN.1 INTEGER type.
 */
public class ASN1Integer extends ASN1Primitive {

	byte[] bytes;

	/**
	 * return an integer from the passed in object
	 *
	 * @param obj
	 *            an ASN1Integer or an object that can be converted into one.
	 * @throws IllegalArgumentException
	 *             if the object cannot be converted.
	 * @return an ASN1Integer instance.
	 */
	public static ASN1Integer getInstance(Object obj) {
		if ((obj == null) || (obj instanceof ASN1Integer)) {
			return (ASN1Integer) obj;
		}

		if (obj instanceof byte[]) {
			try {
				return (ASN1Integer) fromByteArray((byte[]) obj);
			} catch (Exception e) {
				throw new IllegalArgumentException("encoding error in getInstance: " + e.toString());
			}
		}

		throw new IllegalArgumentException("illegal object in getInstance: " + obj.getClass().getName());
	}

	/**
	 * return an Integer from a tagged object.
	 *
	 * @param obj
	 *            the tagged object holding the object we want
	 * @param explicit
	 *            true if the object is meant to be explicitly
	 *            tagged false otherwise.
	 * @throws IllegalArgumentException
	 *             if the tagged object cannot
	 *             be converted.
	 * @return an ASN1Integer instance.
	 */
	public static ASN1Integer getInstance(ASN1TaggedObject obj, boolean explicit) {
		ASN1Primitive o = obj.getObject();

		if (explicit || (o instanceof ASN1Integer)) {
			return getInstance(o);
		} else {
			return new ASN1Integer(ASN1OctetString.getInstance(obj.getObject()).getOctets());
		}
	}

	public ASN1Integer(long value) {
		bytes = BigInteger.valueOf(value).toByteArray();
	}

	public ASN1Integer(BigInteger value) {
		bytes = value.toByteArray();
	}

	public ASN1Integer(byte[] bytes) {
		this(bytes, true);
	}

	ASN1Integer(byte[] bytes, boolean clone) {
		this.bytes = (clone) ? Arrays.clone(bytes) : bytes;
	}

	public BigInteger getValue() {
		return new BigInteger(bytes);
	}

	/**
	 * in some cases positive values get crammed into a space,
	 * that's not quite big enough...
	 *
	 * @return the BigInteger that results from treating this ASN.1 INTEGER as unsigned.
	 */
	public BigInteger getPositiveValue() {
		return new BigInteger(1, bytes);
	}

	@Override
	boolean isConstructed() {
		return false;
	}

	@Override
	int encodedLength() {
		return 1 + StreamUtil.calculateBodyLength(bytes.length) + bytes.length;
	}

	@Override
	void encode(ASN1OutputStream out) throws IOException {
		out.writeEncoded(BERTags.INTEGER, bytes);
	}

	@Override
	public int hashCode() {
		int value = 0;

		for (int i = 0; i != bytes.length; i++) {
			value ^= (bytes[i] & 0xff) << (i % 4);
		}

		return value;
	}

	@Override
	boolean asn1Equals(ASN1Primitive o) {
		if (!(o instanceof ASN1Integer)) {
			return false;
		}

		ASN1Integer other = (ASN1Integer) o;

		return Arrays.areEqual(bytes, other.bytes);
	}

	@Override
	public String toString() {
		return getValue().toString();
	}

}