content: package local.org.bouncycastle.asn1;
  
  import java.io.IOException;
  import java.util.Enumeration;
  import java.util.Vector;
  
  public abstract class ASN1Sequence
      extends ASN1Primitive
  {
      protected Vector seq = new Vector();
  
      /**
       * return an ASN1Sequence from the given object.
       *
       * @param obj the object we want converted.
       * @exception IllegalArgumentException if the object cannot be converted.
       */
      public static ASN1Sequence getInstance(
          Object  obj)
      {
          if (obj == null || obj instanceof ASN1Sequence)
          {
              return (ASN1Sequence)obj;
          }
          else if (obj instanceof ASN1SequenceParser)
          {
              return ASN1Sequence.getInstance(((ASN1SequenceParser)obj).toASN1Primitive());
          }
          else if (obj instanceof byte[])
          {
              try
              {
                  return ASN1Sequence.getInstance(fromByteArray((byte[])obj));
              }
              catch (IOException e)
              {
                  throw new IllegalArgumentException("failed to construct sequence from byte[]: " + e.getMessage());
              }
          }
          else if (obj instanceof ASN1Encodable)
          {
              ASN1Primitive primitive = ((ASN1Encodable)obj).toASN1Primitive();
  
              if (primitive instanceof ASN1Sequence)
              {
                  return (ASN1Sequence)primitive;
              }
          }
  
          throw new IllegalArgumentException("unknown object in getInstance: " + obj.getClass().getName());
      }
  
      /**
       * 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 explicit true if the object is meant to be explicitly tagged,
       *          false otherwise.
       * @exception IllegalArgumentException if the tagged object cannot
       *          be converted.
       */
      public static ASN1Sequence getInstance(
          ASN1TaggedObject    obj,
          boolean             explicit)
      {
          if (explicit)
          {
              if (!obj.isExplicit())
              {
                  throw new IllegalArgumentException("object implicit - explicit expected.");
              }
  
              return ASN1Sequence.getInstance(obj.getObject().toASN1Primitive());
          }
          else
          {
              //
              // 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 instanceof BERTaggedObject)
                  {
                      return new BERSequence(obj.getObject());
                  }
                  else
                  {
                      return new DLSequence(obj.getObject());
                  }
              }
              else
              {
                  if (obj.getObject() instanceof ASN1Sequence)
                  {
                      return (ASN1Sequence)obj.getObject();
                  }
              }
          }
  
          throw new IllegalArgumentException("unknown object in getInstance: " + obj.getClass().getName());
      }
  
      /**
       * create an empty sequence
       */
      protected ASN1Sequence()
      {
      }
  
      /**
       * create a sequence containing one object
       */
      protected ASN1Sequence(
          ASN1Encodable obj)
      {
          seq.addElement(obj);
      }
  
      /**
       * create a sequence containing a vector of objects.
       */
      protected ASN1Sequence(
          ASN1EncodableVector v)
      {
          for (int i = 0; i != v.size(); i++)
          {
              seq.addElement(v.get(i));
          }
      }
  
      /**
       * create a sequence containing a vector of objects.
       */
      protected ASN1Sequence(
          ASN1Encodable[]   array)
      {
          for (int i = 0; i != array.length; i++)
          {
              seq.addElement(array[i]);
          }
      }
  
      public ASN1Encodable[] toArray()
      {
          ASN1Encodable[] values = new ASN1Encodable[this.size()];
  
          for (int i = 0; i != this.size(); i++)
          {
              values[i] = this.getObjectAt(i);
          }
  
          return values;
      }
  
      public Enumeration getObjects()
      {
          return seq.elements();
      }
  
      public ASN1SequenceParser parser()
      {
          final ASN1Sequence outer = this;
  
          return new ASN1SequenceParser()
          {
              private final int max = size();
  
              private int index;
  
              public ASN1Encodable readObject() throws IOException
              {
                  if (index == max)
                  {
                      return null;
                  }
                  
                  ASN1Encodable obj = getObjectAt(index++);
                  if (obj instanceof ASN1Sequence)
                  {
                      return ((ASN1Sequence)obj).parser();
                  }
                  if (obj instanceof ASN1Set)
                  {
                      return ((ASN1Set)obj).parser();
                  }
  
                  return obj;
              }
  
              public ASN1Primitive getLoadedObject()
              {
                  return outer;
              }
              
              public ASN1Primitive toASN1Primitive()
              {
                  return outer;
              }
          };
      }
  
      /**
       * 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 ASN1Encodable getObjectAt(
          int index)
      {
          return (ASN1Encodable)seq.elementAt(index);
      }
  
      /**
       * return the number of objects in this sequence.
       *
       * @return the number of objects in this sequence.
       */
      public int size()
      {
          return seq.size();
      }
  
      public int hashCode()
      {
          Enumeration             e = this.getObjects();
          int                     hashCode = size();
  
          while (e.hasMoreElements())
          {
              Object o = getNext(e);
              hashCode *= 17;
  
              hashCode ^= o.hashCode();
          }
  
          return hashCode;
      }
  
      boolean asn1Equals(
          ASN1Primitive o)
      {
          if (!(o instanceof ASN1Sequence))
          {
              return false;
          }
          
          ASN1Sequence   other = (ASN1Sequence)o;
  
          if (this.size() != other.size())
          {
              return false;
          }
  
          Enumeration s1 = this.getObjects();
          Enumeration s2 = other.getObjects();
  
          while (s1.hasMoreElements())
          {
              ASN1Encodable obj1 = getNext(s1);
              ASN1Encodable obj2 = getNext(s2);
  
              ASN1Primitive o1 = obj1.toASN1Primitive();
              ASN1Primitive o2 = obj2.toASN1Primitive();
  
              if (o1 == o2 || o1.equals(o2))
              {
                  continue;
              }
  
              return false;
          }
  
          return true;
      }
  
      private ASN1Encodable getNext(Enumeration e)
      {
          ASN1Encodable encObj = (ASN1Encodable)e.nextElement();
  
          return encObj;
      }
  
      ASN1Primitive toDERObject()
      {
          ASN1Sequence derSeq = new DERSequence();
  
          derSeq.seq = this.seq;
  
          return derSeq;
      }
  
      ASN1Primitive toDLObject()
      {
          ASN1Sequence dlSeq = new DLSequence();
  
          dlSeq.seq = this.seq;
  
          return dlSeq;
      }
  
      boolean isConstructed()
      {
          return true;
      }
  
      abstract void encode(ASN1OutputStream out)
          throws IOException;
  
      public String toString() 
      {
          return seq.toString();
      }
  }
  