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1
19
20 package com.maverick.crypto.asn1;
21
22 import java.io.ByteArrayOutputStream  ;
23 import java.io.EOFException ;
24 import java.io.IOException ;
25 import java.io.InputStream ;
26 import java.util.Vector ;
27
28 public class BERInputStream
29 extends DERInputStream
30 {
31 private DERObject END_OF_STREAM = new DERObject() {
32 void encode(
33 DEROutputStream out)
34 throws IOException
35 {
36 throw new IOException ("Eeek!");
37 }
38
39 };
40 public BERInputStream(
41 InputStream is)
42 {
43 super(is);
44 }
45
46
49 private byte[] readIndefiniteLengthFully()
50 throws IOException
51 {
52 ByteArrayOutputStream bOut = new ByteArrayOutputStream ();
53 int b, b1;
54
55 b1 = read();
56
57 while ((b = read()) >= 0)
58 {
59 if (b1 == 0 && b == 0)
60 {
61 break;
62 }
63
64 bOut.write(b1);
65 b1 = b;
66 }
67
68 return bOut.toByteArray();
69 }
70
71 private BERConstructedOctetString buildConstructedOctetString()
72 throws IOException
73 {
74 Vector octs = new Vector ();
75
76 for (;;)
77 {
78 DERObject o = readObject();
79
80 if (o == END_OF_STREAM)
81 {
82 break;
83 }
84
85 octs.addElement(o);
86 }
87
88 return new BERConstructedOctetString(octs);
89 }
90
91 public DERObject readObject()
92 throws IOException
93 {
94 int tag = read();
95 if (tag == -1)
96 {
97 throw new EOFException ();
98 }
99
100 int length = readLength();
101
102 if (length < 0) {
104 switch (tag)
105 {
106 case NULL:
107 return null;
108 case SEQUENCE | CONSTRUCTED:
109 BERConstructedSequence seq = new BERConstructedSequence();
110
111 for (;;)
112 {
113 DERObject obj = readObject();
114
115 if (obj == END_OF_STREAM)
116 {
117 break;
118 }
119
120 seq.addObject(obj);
121 }
122 return seq;
123 case OCTET_STRING | CONSTRUCTED:
124 return buildConstructedOctetString();
125 case SET | CONSTRUCTED:
126 ASN1EncodableVector v = new ASN1EncodableVector();
127
128 for (;;)
129 {
130 DERObject obj = readObject();
131
132 if (obj == END_OF_STREAM)
133 {
134 break;
135 }
136
137 v.add(obj);
138 }
139 return new BERSet(v);
140 default:
141 if ((tag & TAGGED) != 0)
145 {
146 if ((tag & 0x1f) == 0x1f)
147 {
148 throw new IOException ("unsupported high tag encountered");
149 }
150
151 if ((tag & CONSTRUCTED) == 0)
155 {
156 byte[] bytes = readIndefiniteLengthFully();
157
158 return new BERTaggedObject(false, tag & 0x1f, new DEROctetString(bytes));
159 }
160
161 DERObject dObj = readObject();
165
166 if (dObj == END_OF_STREAM) {
168 return new DERTaggedObject(tag & 0x1f);
169 }
170
171 DERObject next = readObject();
172
173 if (next == END_OF_STREAM)
178 {
179 return new BERTaggedObject(tag & 0x1f, dObj);
180 }
181
182 seq = new BERConstructedSequence();
186
187 seq.addObject(dObj);
188
189 do
190 {
191 seq.addObject(next);
192 next = readObject();
193 }
194 while (next != END_OF_STREAM);
195
196 return new BERTaggedObject(false, tag & 0x1f, seq);
197 }
198
199 throw new IOException ("unknown BER object encountered");
200 }
201 }
202 else
203 {
204 if (tag == 0 && length == 0) {
206 return END_OF_STREAM;
207 }
208
209 byte[] bytes = new byte[length];
210
211 readFully(bytes);
212
213 return buildObject(tag, bytes);
214 }
215 }
216 }
217 |
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