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Java > Open Source Codes > com > lowagie > bc > asn1 > DERTaggedObject


1 package com.lowagie.bc.asn1;
2
3 import java.io.ByteArrayOutputStream;
4 import java.io.IOException;
5
6 /**
7  * DER TaggedObject - in ASN.1 nottation this is any object proceeded by
8  * a [n] where n is some number - these are assume to follow the construction
9  * rules (as with sequences).
10  */
11 public class DERTaggedObject
12     extends ASN1TaggedObject
13 {
14     /**
15      * @param tagNo the tag number for this object.
16      * @param obj the tagged object.
17      */
18     public DERTaggedObject(
19         int tagNo,
20         DEREncodable obj)
21     {
22         super(tagNo, obj);
23     }
24
25     /**
26      * @param explicit true if an explicitly tagged object.
27      * @param tagNo the tag number for this object.
28      * @param obj the tagged object.
29      */
30     public DERTaggedObject(
31         boolean explicit,
32         int tagNo,
33         DEREncodable obj)
34     {
35         super(explicit, tagNo, obj);
36     }
37
38     /**
39      * create an implicitly tagged object that contains a zero
40      * length sequence.
41      */
42     public DERTaggedObject(
43         int tagNo)
44     {
45         super(false, tagNo, new DERSequence());
46     }
47
48     void encode(
49         DEROutputStream out)
50         throws IOException
51     {
52         if (!empty)
53         {
54             ByteArrayOutputStream bOut = new ByteArrayOutputStream();
55             DEROutputStream dOut = new DEROutputStream(bOut);
56
57             dOut.writeObject(obj);
58             dOut.close();
59
60             byte[] bytes = bOut.toByteArray();
61
62             if (explicit)
63             {
64                 out.writeEncoded(CONSTRUCTED | TAGGED | tagNo, bytes);
65             }
66             else
67             {
68                 //
69 // need to mark constructed types...
70 //
71 if ((bytes[0] & CONSTRUCTED) != 0)
72                 {
73                     bytes[0] = (byte)(CONSTRUCTED | TAGGED | tagNo);
74                 }
75                 else
76                 {
77                     bytes[0] = (byte)(TAGGED | tagNo);
78                 }
79
80                 out.write(bytes);
81             }
82         }
83         else
84         {
85             out.writeEncoded(CONSTRUCTED | TAGGED | tagNo, new byte[0]);
86         }
87     }
88 }
89
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