Target.cs :  » PDF » iTextSharp » Org » BouncyCastle » Asn1 » X509 » C# / CSharp Open Source

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);
    }
  }
}