Source code: gnu/javax/crypto/sasl/OutputBuffer.java
1 /* OutputBuffer.java --
2 Copyright (C) 2003, 2006 Free Software Foundation, Inc.
3
4 This file is a part of GNU Classpath.
5
6 GNU Classpath is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or (at
9 your option) any later version.
10
11 GNU Classpath is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with GNU Classpath; if not, write to the Free Software
18 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
19 USA
20
21 Linking this library statically or dynamically with other modules is
22 making a combined work based on this library. Thus, the terms and
23 conditions of the GNU General Public License cover the whole
24 combination.
25
26 As a special exception, the copyright holders of this library give you
27 permission to link this library with independent modules to produce an
28 executable, regardless of the license terms of these independent
29 modules, and to copy and distribute the resulting executable under
30 terms of your choice, provided that you also meet, for each linked
31 independent module, the terms and conditions of the license of that
32 module. An independent module is a module which is not derived from
33 or based on this library. If you modify this library, you may extend
34 this exception to your version of the library, but you are not
35 obligated to do so. If you do not wish to do so, delete this
36 exception statement from your version. */
37
38
39 package gnu.javax.crypto.sasl;
40
41 import gnu.java.security.Registry;
42 import gnu.java.security.util.Util;
43
44 import java.io.ByteArrayOutputStream;
45 import java.io.IOException;
46 import java.math.BigInteger;
47
48 /**
49 * <p>The implementation of an outgoing SASL buffer.</p>
50 *
51 * <p>The data elements this class caters for are described in [1].</p>
52 *
53 * <p>References:</p>
54 * <ol>
55 * <li><a href="http://www.ietf.org/internet-drafts/draft-burdis-cat-srp-sasl-09.txt">
56 * Secure Remote Password Authentication Mechanism</a>;<br/>
57 * draft-burdis-cat-srp-sasl-09,<br/>
58 * <a href="mailto:keith@rucus.ru.ac.za">Keith Burdis</a> and
59 * <a href="mailto:raif@forge.com.au">Raïf S. Naffah</a>.</li>
60 * </ol>
61 */
62 public class OutputBuffer
63 {
64
65 // Constants and variables
66 // -------------------------------------------------------------------------
67
68 /** The internal output stream. */
69 private ByteArrayOutputStream out;
70
71 // Constructor(s)
72 // -------------------------------------------------------------------------
73
74 public OutputBuffer()
75 {
76 super();
77
78 out = new ByteArrayOutputStream();
79 }
80
81 // Class methods
82 // -------------------------------------------------------------------------
83
84 // Instance methods
85 // -------------------------------------------------------------------------
86
87 /**
88 * <p>Encodes a SASL scalar quantity, <code>count</code>-octet long, to the
89 * current buffer.</p>
90 *
91 * @param count number of octets to encode <code>b</code> with.
92 * @param b the scalar quantity.
93 * @throws SaslEncodingException if an encoding size constraint is violated.
94 * @throws IOException if any other I/O exception occurs during the operation.
95 */
96 public void setScalar(int count, int b) throws IOException
97 {
98 if (count < 0 || count > 4)
99 {
100 throw new SaslEncodingException("Invalid SASL scalar octet count: "
101 + String.valueOf(count));
102 }
103 byte[] element = new byte[count];
104 for (int i = count; --i >= 0; b >>>= 8)
105 {
106 element[i] = (byte) b;
107 }
108 out.write(element);
109 }
110
111 /**
112 * <p>Encodes a SASL OS to the current buffer.</p>
113 *
114 * @param b the OS element.
115 * @throws SaslEncodingException if an encoding size constraint is violated.
116 * @throws IOException if any other I/O exception occurs during the operation.
117 */
118 public void setOS(byte[] b) throws IOException
119 {
120 final int length = b.length;
121 if (length > Registry.SASL_ONE_BYTE_MAX_LIMIT)
122 {
123 throw new SaslEncodingException("SASL octet-sequence too long");
124 }
125 out.write(length & 0xFF);
126 out.write(b);
127 }
128
129 /**
130 * <p>Encodes a SASL EOS to the current buffer.</p>
131 *
132 * @param b the EOS element.
133 * @throws SaslEncodingException if an encoding size constraint is violated.
134 * @throws IOException if any other I/O exception occurs during the operation.
135 */
136 public void setEOS(byte[] b) throws IOException
137 {
138 final int length = b.length;
139 if (length > Registry.SASL_TWO_BYTE_MAX_LIMIT)
140 {
141 throw new SaslEncodingException("SASL extended octet-sequence too long");
142 }
143 byte[] lengthBytes = { (byte) (length >>> 8), (byte) length };
144 out.write(lengthBytes);
145 out.write(b);
146 }
147
148 /**
149 * <p>Encodes a SASL MPI to the current buffer.</p>
150 *
151 * @param val the MPI element.
152 * @throws SaslEncodingException if an encoding size constraint is violated.
153 * @throws IOException if any other I/O exception occurs during the operation.
154 */
155 public void setMPI(BigInteger val) throws IOException
156 {
157 byte[] b = Util.trim(val);
158 final int length = b.length;
159 if (length > Registry.SASL_TWO_BYTE_MAX_LIMIT)
160 {
161 throw new SaslEncodingException("SASL multi-precision integer too long");
162 }
163 byte[] lengthBytes = { (byte) (length >>> 8), (byte) length };
164 out.write(lengthBytes);
165 out.write(b);
166 }
167
168 /**
169 * <p>Encodes a SASL Text to the current buffer.</p>
170 *
171 * @param str the Text element.
172 * @throws SaslEncodingException if an encoding size constraint is violated.
173 * @throws SaslEncodingException if the UTF-8 encoding is not supported on
174 * this platform.
175 * @throws IOException if any other I/O exception occurs during the operation.
176 */
177 public void setText(String str) throws IOException
178 {
179 byte[] b = str.getBytes("UTF8");
180 final int length = b.length;
181 if (length > Registry.SASL_TWO_BYTE_MAX_LIMIT)
182 {
183 throw new SaslEncodingException("SASL text too long");
184 }
185 byte[] lengthBytes = { (byte) (length >>> 8), (byte) length };
186 out.write(lengthBytes);
187 out.write(b);
188 }
189
190 /**
191 * <p>Returns the encoded form of the current buffer including the 4-byte
192 * length header.</p>
193 *
194 * @throws SaslEncodingException if an encoding size constraint is violated.
195 */
196 public byte[] encode() throws SaslEncodingException
197 {
198 byte[] buffer = wrap();
199 final int length = buffer.length;
200 byte[] result = new byte[length + 4];
201 result[0] = (byte) (length >>> 24);
202 result[1] = (byte) (length >>> 16);
203 result[2] = (byte) (length >>> 8);
204 result[3] = (byte) length;
205 System.arraycopy(buffer, 0, result, 4, length);
206
207 return result;
208 }
209
210 /**
211 * <p>Returns the encoded form of the current buffer excluding the 4-byte
212 * length header.</p>
213 *
214 * @throws SaslEncodingException if an encoding size constraint is violated.
215 */
216 public byte[] wrap() throws SaslEncodingException
217 {
218 final int length = out.size();
219 if (length > Registry.SASL_BUFFER_MAX_LIMIT || length < 0)
220 {
221 throw new SaslEncodingException("SASL buffer too long");
222 }
223 return out.toByteArray();
224 }
225 }