1 files changed, 139 insertions, 0 deletions
diff --git a/crypto/src/asn1/x509/Target.cs b/crypto/src/asn1/x509/Target.cs
new file mode 100644
index 000000000..309b28c95
--- /dev/null
+++ b/crypto/src/asn1/x509/Target.cs
@@ -0,0 +1,139 @@
+using System;
+
+namespace Org.BouncyCastle.Asn1.X509
+{
+	/**
+	 * Target structure used in target information extension for attribute
+	 * certificates from RFC 3281.
+	 * 
+	 * <pre>
+	 *     Target  ::= CHOICE {
+	 *       targetName          [0] GeneralName,
+	 *       targetGroup         [1] GeneralName,
+	 *       targetCert          [2] TargetCert
+	 *     }
+	 * </pre>
+	 * 
+	 * <p>
+	 * The targetCert field is currently not supported and must not be used
+	 * according to RFC 3281.</p>
+	 */
+	public class Target
+		: Asn1Encodable, IAsn1Choice
+	{
+		public enum Choice
+		{
+			Name = 0,
+			Group = 1
+		};
+
+		private readonly GeneralName targetName;
+		private readonly GeneralName targetGroup;
+
+		/**
+		* Creates an instance of a Target from the given object.
+		* <p>
+		* <code>obj</code> can be a Target or a {@link Asn1TaggedObject}</p>
+		* 
+		* @param obj The object.
+		* @return A Target instance.
+		* @throws ArgumentException if the given object cannot be
+		*             interpreted as Target.
+		*/
+		public static Target GetInstance(
+			object obj)
+		{
+			if (obj is Target)
+			{
+				return (Target) obj;
+			}
+
+			if (obj is Asn1TaggedObject)
+			{
+				return new Target((Asn1TaggedObject) obj);
+			}
+
+			throw new ArgumentException("unknown object in factory: " + obj.GetType().Name, "obj");
+		}
+
+		/**
+		 * Constructor from Asn1TaggedObject.
+		 * 
+		 * @param tagObj The tagged object.
+		 * @throws ArgumentException if the encoding is wrong.
+		 */
+		private Target(
+			Asn1TaggedObject tagObj)
+		{
+			switch ((Choice) tagObj.TagNo)
+			{
+				case Choice.Name:	// GeneralName is already a choice so explicit
+					targetName = GeneralName.GetInstance(tagObj, true);
+					break;
+				case Choice.Group:
+					targetGroup = GeneralName.GetInstance(tagObj, true);
+					break;
+				default:
+					throw new ArgumentException("unknown tag: " + tagObj.TagNo);
+			}
+		}
+
+		/**
+		 * Constructor from given details.
+		 * <p>
+		 * Exactly one of the parameters must be not <code>null</code>.</p>
+		 *
+		 * @param type the choice type to apply to the name.
+		 * @param name the general name.
+		 * @throws ArgumentException if type is invalid.
+		 */
+		public Target(
+			Choice		type,
+			GeneralName	name)
+			: this(new DerTaggedObject((int) type, name))
+		{
+		}
+
+		/**
+		 * @return Returns the targetGroup.
+		 */
+		public virtual GeneralName TargetGroup
+		{
+			get { return targetGroup; }
+		}
+
+		/**
+		 * @return Returns the targetName.
+		 */
+		public virtual GeneralName TargetName
+		{
+			get { return targetName; }
+		}
+
+		/**
+		 * Produce an object suitable for an Asn1OutputStream.
+		 * 
+		 * Returns:
+		 * 
+		 * <pre>
+		 *     Target  ::= CHOICE {
+		 *       targetName          [0] GeneralName,
+		 *       targetGroup         [1] GeneralName,
+		 *       targetCert          [2] TargetCert
+		 *     }
+		 * </pre>
+		 * 
+		 * @return an Asn1Object
+		 */
+		public override Asn1Object ToAsn1Object()
+		{
+			// GeneralName is a choice already so most be explicitly tagged
+			if (targetName != null)
+			{
+				return new DerTaggedObject(true, 0, targetName);
+			}
+
+			return new DerTaggedObject(true, 1, targetGroup);
+		}
+	}
+}