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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 io.netty.handler.codec.http.websocketx;
17  
18  import io.netty.buffer.ByteBuf;
19  import io.netty.buffer.Unpooled;
20  import io.netty.handler.codec.base64.Base64;
21  import io.netty.util.CharsetUtil;
22  import io.netty.util.concurrent.FastThreadLocal;
23  
24  import java.security.MessageDigest;
25  import java.security.NoSuchAlgorithmException;
26  
27  /**
28   * A utility class mainly for use by web sockets
29   */
30  final class WebSocketUtil {
31  
32      private static final FastThreadLocal<MessageDigest> MD5 = new FastThreadLocal<MessageDigest>() {
33          @Override
34          protected MessageDigest initialValue() throws Exception {
35              try {
36                  //Try to get a MessageDigest that uses MD5
37                  return MessageDigest.getInstance("MD5");
38              } catch (NoSuchAlgorithmException e) {
39                  //This shouldn't happen! How old is the computer?
40                  throw new InternalError("MD5 not supported on this platform - Outdated?");
41              }
42          }
43      };
44  
45      private static final FastThreadLocal<MessageDigest> SHA1 = new FastThreadLocal<MessageDigest>() {
46          @Override
47          protected MessageDigest initialValue() throws Exception {
48              try {
49                  //Try to get a MessageDigest that uses SHA1
50                  return MessageDigest.getInstance("SHA1");
51              } catch (NoSuchAlgorithmException e) {
52                  //This shouldn't happen! How old is the computer?
53                  throw new InternalError("SHA-1 not supported on this platform - Outdated?");
54              }
55          }
56      };
57  
58      /**
59       * Performs a MD5 hash on the specified data
60       *
61       * @param data The data to hash
62       * @return The hashed data
63       */
64      static byte[] md5(byte[] data) {
65          // TODO(normanmaurer): Create md5 method that not need MessageDigest.
66          return digest(MD5, data);
67      }
68  
69      /**
70       * Performs a SHA-1 hash on the specified data
71       *
72       * @param data The data to hash
73       * @return The hashed data
74       */
75      static byte[] sha1(byte[] data) {
76          // TODO(normanmaurer): Create sha1 method that not need MessageDigest.
77          return digest(SHA1, data);
78      }
79  
80      private static byte[] digest(FastThreadLocal<MessageDigest> digestFastThreadLocal, byte[] data) {
81          MessageDigest digest = digestFastThreadLocal.get();
82          digest.reset();
83          return digest.digest(data);
84      }
85  
86      /**
87       * Performs base64 encoding on the specified data
88       *
89       * @param data The data to encode
90       * @return An encoded string containing the data
91       */
92      static String base64(byte[] data) {
93          ByteBuf encodedData = Unpooled.wrappedBuffer(data);
94          ByteBuf encoded = Base64.encode(encodedData);
95          String encodedString = encoded.toString(CharsetUtil.UTF_8);
96          encoded.release();
97          return encodedString;
98      }
99  
100     /**
101      * Creates an arbitrary number of random bytes
102      *
103      * @param size the number of random bytes to create
104      * @return An array of random bytes
105      */
106     static byte[] randomBytes(int size) {
107         byte[] bytes = new byte[size];
108 
109         for (int index = 0; index < size; index++) {
110             bytes[index] = (byte) randomNumber(0, 255);
111         }
112 
113         return bytes;
114     }
115 
116     /**
117      * Generates a pseudo-random number
118      *
119      * @param minimum The minimum allowable value
120      * @param maximum The maximum allowable value
121      * @return A pseudo-random number
122      */
123     static int randomNumber(int minimum, int maximum) {
124         return (int) (Math.random() * maximum + minimum);
125     }
126 
127     /**
128      * A private constructor to ensure that instances of this class cannot be made
129      */
130     private WebSocketUtil() {
131         // Unused
132     }
133 }