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1   /*
2    * Copyright 2012 The Netty Project
3    *
4    * The Netty Project licenses this file to you under the Apache License,
5    * version 2.0 (the "License"); you may not use this file except in compliance
6    * with the License. You may obtain a copy of the License at:
7    *
8    *   http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13   * License for the specific language governing permissions and limitations
14   * under the License.
15   */
16  package org.jboss.netty.handler.codec.http.websocketx;
17  
18  import java.security.MessageDigest;
19  import java.security.NoSuchAlgorithmException;
20  
21  import org.jboss.netty.buffer.ChannelBuffer;
22  import org.jboss.netty.buffer.ChannelBuffers;
23  import org.jboss.netty.handler.codec.base64.Base64;
24  import org.jboss.netty.util.CharsetUtil;
25  
26  /**
27   * TODO Document me.
28   */
29  final class WebSocketUtil {
30  
31      /**
32       * Performs an MD5 hash
33       *
34       * @param buffer
35       *            buffer to hash
36       * @return Hashed data
37       */
38      static ChannelBuffer md5(ChannelBuffer buffer) {
39          try {
40              MessageDigest md = MessageDigest.getInstance("MD5");
41              if (buffer.hasArray()) {
42                  int offset = buffer.arrayOffset() + buffer.readerIndex();
43                  int length = buffer.readableBytes();
44                  md.update(buffer.array(), offset, length);
45              } else {
46                  md.update(buffer.toByteBuffer());
47              }
48              return ChannelBuffers.wrappedBuffer(md.digest());
49          } catch (NoSuchAlgorithmException e) {
50              throw new InternalError("MD5 not supported on this platform");
51          }
52      }
53  
54      /**
55       * Performs an SHA-1 hash
56       *
57       * @param buffer
58       *            buffer to hash
59       * @return Hashed data
60       */
61      static ChannelBuffer sha1(ChannelBuffer buffer) {
62          try {
63              MessageDigest md = MessageDigest.getInstance("SHA1");
64              if (buffer.hasArray()) {
65                  int offset = buffer.arrayOffset() + buffer.readerIndex();
66                  int length = buffer.readableBytes();
67                  md.update(buffer.array(), offset, length);
68              } else {
69                  md.update(buffer.toByteBuffer());
70              }
71              return ChannelBuffers.wrappedBuffer(md.digest());
72          } catch (NoSuchAlgorithmException e) {
73              throw new InternalError("SHA-1 not supported on this platform");
74          }
75      }
76  
77      /**
78       * Base 64 encoding
79       *
80       * @param buffer
81       *            Bytes to encode
82       * @return encoded string
83       */
84      static String base64(ChannelBuffer buffer) {
85          return Base64.encode(buffer).toString(CharsetUtil.UTF_8);
86      }
87  
88      /**
89       * Creates some random bytes
90       *
91       * @param size
92       *            Number of random bytes to create
93       * @return random bytes
94       */
95      static byte[] randomBytes(int size) {
96          byte[] bytes = new byte[size];
97  
98          for (int i = 0; i < size; i++) {
99              bytes[i] = (byte) randomNumber(0, 255);
100         }
101 
102         return bytes;
103     }
104 
105     /**
106      * Generates a random number
107      *
108      * @param min
109      *            Minimum value
110      * @param max
111      *            Maximum value
112      * @return Random number
113      */
114     static int randomNumber(int min, int max) {
115         return (int) (Math.random() * max + min);
116     }
117 
118     private WebSocketUtil() {
119         // Unused
120     }
121 }