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      1 package org.bouncycastle.asn1;
      2 
      3 import java.io.IOException;
      4 import java.util.Enumeration;
      5 
      6 /**
      7  * The DLSequence encodes a SEQUENCE using definite length form.
      8  */
      9 public class DLSequence
     10     extends ASN1Sequence
     11 {
     12     private int bodyLength = -1;
     13 
     14     /**
     15      * Create an empty sequence
     16      */
     17     public DLSequence()
     18     {
     19     }
     20 
     21     /**
     22      * create a sequence containing one object
     23      * @param obj the object to go in the sequence.
     24      */
     25     public DLSequence(
     26         ASN1Encodable obj)
     27     {
     28         super(obj);
     29     }
     30 
     31     /**
     32      * create a sequence containing a vector of objects.
     33      * @param v the vector of objects to make up the sequence.
     34      */
     35     public DLSequence(
     36         ASN1EncodableVector v)
     37     {
     38         super(v);
     39     }
     40 
     41     /**
     42      * create a sequence containing an array of objects.
     43      * @param array the array of objects to make up the sequence.
     44      */
     45     public DLSequence(
     46         ASN1Encodable[] array)
     47     {
     48         super(array);
     49     }
     50 
     51     private int getBodyLength()
     52         throws IOException
     53     {
     54         if (bodyLength < 0)
     55         {
     56             int length = 0;
     57 
     58             for (Enumeration e = this.getObjects(); e.hasMoreElements();)
     59             {
     60                 Object obj = e.nextElement();
     61 
     62                 length += ((ASN1Encodable)obj).toASN1Primitive().toDLObject().encodedLength();
     63             }
     64 
     65             bodyLength = length;
     66         }
     67 
     68         return bodyLength;
     69     }
     70 
     71     int encodedLength()
     72         throws IOException
     73     {
     74         int length = getBodyLength();
     75 
     76         return 1 + StreamUtil.calculateBodyLength(length) + length;
     77     }
     78 
     79     /**
     80      * A note on the implementation:
     81      * <p>
     82      * As DL requires the constructed, definite-length model to
     83      * be used for structured types, this varies slightly from the
     84      * ASN.1 descriptions given. Rather than just outputting SEQUENCE,
     85      * we also have to specify CONSTRUCTED, and the objects length.
     86      */
     87     void encode(
     88         ASN1OutputStream out)
     89         throws IOException
     90     {
     91         ASN1OutputStream dOut = out.getDLSubStream();
     92         int length = getBodyLength();
     93 
     94         out.write(BERTags.SEQUENCE | BERTags.CONSTRUCTED);
     95         out.writeLength(length);
     96 
     97         for (Enumeration e = this.getObjects(); e.hasMoreElements();)
     98         {
     99             Object obj = e.nextElement();
    100 
    101             dOut.writeObject((ASN1Encodable)obj);
    102         }
    103     }
    104 }