Asn1Sequence.cs :  » PDF » iTextSharp » Org » BouncyCastle » Asn1 » C# / CSharp Open Source

using System;
using System.Collections;

using Org.BouncyCastle.Utilities.Collections;

namespace Org.BouncyCastle.Asn1{
    public abstract class Asn1Sequence
    : Asn1Object, IEnumerable
    {
        private readonly ArrayList seq;

    /**
         * return an Asn1Sequence from the given object.
         *
         * @param obj the object we want converted.
         * @exception ArgumentException if the object cannot be converted.
         */
        public static Asn1Sequence GetInstance(
            object obj)
        {
            if (obj == null || obj is Asn1Sequence)
            {
                return (Asn1Sequence)obj;
            }

      throw new ArgumentException("Unknown object in GetInstance: " + obj.GetType().FullName, "obj");
    }

    /**
         * Return an ASN1 sequence from a tagged object. There is a special
         * case here, if an object appears to have been explicitly tagged on
         * reading but we were expecting it to be implicitly tagged in the
         * normal course of events it indicates that we lost the surrounding
         * sequence - so we need to add it back (this will happen if the tagged
         * object is a sequence that contains other sequences). If you are
         * dealing with implicitly tagged sequences you really <b>should</b>
         * be using this method.
         *
         * @param obj the tagged object.
         * @param explicitly true if the object is meant to be explicitly tagged,
         *          false otherwise.
         * @exception ArgumentException if the tagged object cannot
         *          be converted.
         */
        public static Asn1Sequence GetInstance(
            Asn1TaggedObject  obj,
            bool        explicitly)
        {
      Asn1Object inner = obj.GetObject();

      if (explicitly)
            {
                if (!obj.IsExplicit())
                    throw new ArgumentException("object implicit - explicit expected.");

        return (Asn1Sequence) inner;
            }

      //
            // constructed object which appears to be explicitly tagged
            // when it should be implicit means we have to add the
            // surrounding sequence.
            //
            if (obj.IsExplicit())
            {
                if (obj is BerTaggedObject)
                {
                    return new BerSequence(inner);
                }

        return new DerSequence(inner);
            }

      if (inner is Asn1Sequence)
            {
                return (Asn1Sequence) inner;
            }

      throw new ArgumentException("Unknown object in GetInstance: " + obj.GetType().FullName, "obj");
    }

    protected internal Asn1Sequence(
      int capacity)
    {
      seq = new ArrayList(capacity);
    }

    public virtual IEnumerator GetEnumerator()
    {
      return seq.GetEnumerator();
    }

    [Obsolete("Use GetEnumerator() instead")]
    public IEnumerator GetObjects()
        {
            return GetEnumerator();
        }

    private class Asn1SequenceParserImpl
      : Asn1SequenceParser
    {
      private readonly Asn1Sequence outer;
      private readonly int max;
      private int index;

      public Asn1SequenceParserImpl(
        Asn1Sequence outer)
      {
        this.outer = outer;
        this.max = outer.Count;
      }

      public IAsn1Convertible ReadObject()
      {
        if (index == max)
          return null;

        Asn1Encodable obj = outer[index++];

        if (obj is Asn1Sequence)
          return ((Asn1Sequence)obj).Parser;

        if (obj is Asn1Set)
          return ((Asn1Set)obj).Parser;

        // NB: Asn1OctetString implements Asn1OctetStringParser directly
//        if (obj is Asn1OctetString)
//          return ((Asn1OctetString)obj).Parser;

        return obj;
      }

      public Asn1Object ToAsn1Object()
      {
        return outer;
      }
    }

    public virtual Asn1SequenceParser Parser
    {
      get { return new Asn1SequenceParserImpl(this); }
    }

        /**
         * return the object at the sequence position indicated by index.
         *
         * @param index the sequence number (starting at zero) of the object
         * @return the object at the sequence position indicated by index.
         */
    public virtual Asn1Encodable this[int index]
    {
      get { return (Asn1Encodable) seq[index]; }
    }

    [Obsolete("Use 'object[index]' syntax instead")]
        public Asn1Encodable GetObjectAt(
            int index)
        {
             return this[index];
        }

    [Obsolete("Use 'Count' property instead")]
    public int Size
        {
      get { return Count; }
        }

    public virtual int Count
    {
      get { return seq.Count; }
    }

    protected override int Asn1GetHashCode()
    {
      int hc = Count;

      foreach (object o in this)
      {
        hc *= 17;
        if (o != null)
                {
          hc ^= o.GetHashCode();
                }
            }

      return hc;
        }

    protected override bool Asn1Equals(
      Asn1Object asn1Object)
    {
      Asn1Sequence other = asn1Object as Asn1Sequence;

      if (other == null)
                return false;

      if (Count != other.Count)
            {
                return false;
            }

            IEnumerator s1 = GetEnumerator();
            IEnumerator s2 = other.GetEnumerator();

      while (s1.MoveNext() && s2.MoveNext())
      {
//        if (!Platform.Equals(s1.Current, s2.Current))
        Asn1Object o1 = ((Asn1Encodable) s1.Current).ToAsn1Object();

        if (!o1.Equals(s2.Current))
        {
          return false;
        }
      }

      return true;
        }

    protected internal void AddObject(
            Asn1Encodable obj)
        {
            seq.Add(obj);
        }

    public override string ToString()
    {
      return CollectionUtilities.ToString(seq);
    }
    }
}