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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.commons.fileupload.util.mime;
18  
19  import static org.junit.Assert.assertArrayEquals;
20  import static org.junit.Assert.assertTrue;
21  import static org.junit.Assert.fail;
22  
23  import java.io.ByteArrayOutputStream;
24  import java.io.IOException;
25  import java.io.UnsupportedEncodingException;
26  
27  import org.junit.Test;
28  
29  /**
30   * @since 1.3
31   */
32  public final class Base64DecoderTestCase {
33  
34      private static final String US_ASCII_CHARSET = "US-ASCII";
35  
36      /**
37       * Tests RFC 4648 section 10 test vectors.
38       * <ul>
39       * <li>BASE64("") = ""</li>
40       * <li>BASE64("f") = "Zg=="</li>
41       * <li>BASE64("fo") = "Zm8="</li>
42       * <li>BASE64("foo") = "Zm9v"</li>
43       * <li>BASE64("foob") = "Zm9vYg=="</li>
44       * <li>BASE64("fooba") = "Zm9vYmE="</li>
45       * <li>BASE64("foobar") = "Zm9vYmFy"</li>
46       * </ul>
47       *
48       * @see <a href="http://tools.ietf.org/html/rfc4648">http://tools.ietf.org/html/rfc4648</a>
49       */
50      @Test
51      public void rfc4648Section10Decode() throws Exception {
52          assertEncoded("", "");
53          assertEncoded("f", "Zg==");
54          assertEncoded("fo", "Zm8=");
55          assertEncoded("foo", "Zm9v");
56          assertEncoded("foob", "Zm9vYg==");
57          assertEncoded("fooba", "Zm9vYmE=");
58          assertEncoded("foobar", "Zm9vYmFy");
59      }
60  
61      /**
62       * Test our decode with pad character in the middle.
63       * Continues provided that the padding is in the correct place,
64       * i.e. concatenated valid strings decode OK.
65       */
66      @Test
67      public void decodeWithInnerPad() throws Exception {
68          assertEncoded("Hello WorldHello World", "SGVsbG8gV29ybGQ=SGVsbG8gV29ybGQ=");
69      }
70  
71      /**
72       * Ignores non-BASE64 bytes.
73       */
74      @Test
75      public void nonBase64Bytes() throws Exception {
76          assertEncoded("Hello World", "S?G!V%sbG 8g\rV\t\n29ybGQ*=");
77      }
78  
79      @Test(expected = IOException.class)
80      public void truncatedString() throws Exception {
81          final byte[] x = new byte[]{'n'};
82          Base64Decoder.decode(x, new ByteArrayOutputStream());
83      }
84  
85      @Test
86      public void decodeTrailingJunk() throws Exception {
87          assertEncoded("foobar", "Zm9vYmFy!!!");
88      }
89  
90      // If there are valid trailing Base64 chars, complain
91      @Test
92      public void decodeTrailing1() throws Exception {
93          assertIOException("truncated", "Zm9vYmFy1");
94      }
95  
96      // If there are valid trailing Base64 chars, complain
97      @Test
98      public void decodeTrailing2() throws Exception {
99          assertIOException("truncated", "Zm9vYmFy12");
100     }
101 
102     // If there are valid trailing Base64 chars, complain
103     @Test
104     public void decodeTrailing3() throws Exception {
105         assertIOException("truncated", "Zm9vYmFy123");
106     }
107 
108     @Test
109     public void badPadding() throws Exception {
110         assertIOException("incorrect padding, 4th byte", "Zg=a");
111     }
112 
113     @Test
114     public void badPaddingLeading1() throws Exception {
115         assertIOException("incorrect padding, first two bytes cannot be padding", "=A==");
116     }
117 
118     @Test
119     public void badPaddingLeading2() throws Exception {
120         assertIOException("incorrect padding, first two bytes cannot be padding", "====");
121     }
122 
123     // This input causes java.lang.ArrayIndexOutOfBoundsException: 1
124     // in the Java 6 method DatatypeConverter.parseBase64Binary(String)
125     // currently reported as truncated (the last chunk consists just of '=')
126     @Test
127     public void badLength() throws Exception {
128         assertIOException("truncated", "Zm8==");
129     }
130 
131     // These inputs cause java.lang.ArrayIndexOutOfBoundsException
132     // in the Java 6 method DatatypeConverter.parseBase64Binary(String)
133     // The non-ASCII characters should just be ignored
134     @Test
135     public void nonASCIIcharacter() throws Exception {
136         assertEncoded("f","Zg=À="); // A-grave
137         assertEncoded("f","Zg=\u0100=");
138     }
139 
140     private static void assertEncoded(String clearText, String encoded) throws Exception {
141         byte[] expected = clearText.getBytes(US_ASCII_CHARSET);
142 
143         ByteArrayOutputStream out = new ByteArrayOutputStream(encoded.length());
144         byte[] encodedData = encoded.getBytes(US_ASCII_CHARSET);
145         Base64Decoder.decode(encodedData, out);
146         byte[] actual = out.toByteArray();
147 
148         assertArrayEquals(expected, actual);
149     }
150 
151     private static void assertIOException(String messageText, String encoded) throws UnsupportedEncodingException {
152         ByteArrayOutputStream out = new ByteArrayOutputStream(encoded.length());
153         byte[] encodedData = encoded.getBytes(US_ASCII_CHARSET);
154         try {
155             Base64Decoder.decode(encodedData, out);
156             fail("Expected IOException");
157         } catch (IOException e) {
158             String em = e.getMessage();
159             assertTrue("Expected to find " + messageText + " in '" + em + "'",em.contains(messageText));
160         }
161     }
162 
163 }