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 * https://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
18 package org.apache.commons.codec.binary;
19
20 import java.io.InputStream;
21
22 import org.apache.commons.codec.CodecPolicy;
23 import org.apache.commons.codec.binary.BaseNCodecInputStream.AbstracBuilder; // NOPMD: Required by ECJ (Eclipse)
24
25 /**
26 * Provides Base32 decoding in a streaming fashion (unlimited size). When encoding the default lineLength is 76 characters and the default lineEnding is CRLF,
27 * but these can be overridden by using the appropriate constructor.
28 * <p>
29 * The default behavior of the Base32InputStream is to DECODE, whereas the default behavior of the Base32OutputStream is to ENCODE, but this behavior can be
30 * overridden by using a different constructor.
31 * </p>
32 * <p>
33 * Since this class operates directly on byte streams, and not character streams, it is hard-coded to only encode/decode character encodings which are
34 * compatible with the lower 127 ASCII chart (ISO-8859-1, Windows-1252, UTF-8, etc).
35 * </p>
36 * <p>
37 * You can set the decoding behavior when the input bytes contain leftover trailing bits that cannot be created by a valid encoding. These can be bits that are
38 * unused from the final character or entire characters. The default mode is lenient decoding.
39 * </p>
40 * <ul>
41 * <li>Lenient: Any trailing bits are composed into 8-bit bytes where possible. The remainder are discarded.
42 * <li>Strict: The decoding will raise an {@link IllegalArgumentException} if trailing bits are not part of a valid encoding. Any unused bits from the final
43 * character must be zero. Impossible counts of entire final characters are not allowed.
44 * </ul>
45 * <p>
46 * When strict decoding is enabled it is expected that the decoded bytes will be re-encoded to a byte array that matches the original, i.e. no changes occur on
47 * the final character. This requires that the input bytes use the same padding and alphabet as the encoder.
48 * </p>
49 *
50 * @see Base32
51 * @see <a href="https://www.ietf.org/rfc/rfc4648.txt">RFC 4648</a>
52 * @since 1.5
53 */
54 public class Base32InputStream extends BaseNCodecInputStream<Base32, Base32InputStream, Base32InputStream.Builder> {
55
56 /**
57 * Builds instances of Base32InputStream.
58 *
59 * @since 1.20.0
60 */
61 public static class Builder extends AbstracBuilder<Base32InputStream, Base32, Builder> {
62
63 /**
64 * Constructs a new instance.
65 */
66 public Builder() {
67 // empty
68 }
69
70 @Override
71 public Base32InputStream get() {
72 return new Base32InputStream(this);
73 }
74
75 @Override
76 protected Base32 newBaseNCodec() {
77 return new Base32();
78 }
79 }
80
81 /**
82 * Constructs a new Builder.
83 *
84 * @return a new Builder.
85 * @since 1.20.0
86 */
87 public static Builder builder() {
88 return new Builder();
89 }
90
91 private Base32InputStream(final Builder builder) {
92 super(builder);
93 }
94
95 /**
96 * Constructs a Base32InputStream such that all data read is Base32-decoded from the original provided InputStream.
97 *
98 * @param inputStream InputStream to wrap.
99 */
100 public Base32InputStream(final InputStream inputStream) {
101 super(builder().setInputStream(inputStream));
102 }
103
104 /**
105 * Constructs a Base32InputStream such that all data read is either Base32-encoded or Base32-decoded from the original provided InputStream.
106 *
107 * @param inputStream InputStream to wrap.
108 * @param encode true if we should encode all data read from us, false if we should decode.
109 * @deprecated Use {@link #builder()} and {@link Builder}.
110 */
111 @Deprecated
112 public Base32InputStream(final InputStream inputStream, final boolean encode) {
113 super(builder().setInputStream(inputStream).setEncode(encode));
114 }
115
116 /**
117 * Constructs a Base32InputStream such that all data read is either Base32-encoded or Base32-decoded from the original provided InputStream.
118 *
119 * @param inputStream InputStream to wrap.
120 * @param encode true if we should encode all data read from us, false if we should decode.
121 * @param lineLength If doEncode is true, each line of encoded data will contain lineLength characters (rounded down to the nearest multiple of 4). If
122 * lineLength <= 0, the encoded data is not divided into lines. If doEncode is false, lineLength is ignored.
123 * @param lineSeparator If doEncode is true, each line of encoded data will be terminated with this byte sequence (for example \r\n). If lineLength <= 0,
124 * the lineSeparator is not used. If doEncode is false lineSeparator is ignored.
125 * @deprecated Use {@link #builder()} and {@link Builder}.
126 */
127 @Deprecated
128 public Base32InputStream(final InputStream inputStream, final boolean encode, final int lineLength, final byte[] lineSeparator) {
129 super(builder().setInputStream(inputStream).setEncode(encode)
130 .setBaseNCodec(Base32.builder().setLineLength(lineLength).setLineSeparator(lineSeparator).get()));
131 }
132
133 /**
134 * Constructs a Base32InputStream such that all data read is either Base32-encoded or Base32-decoded from the original provided InputStream.
135 *
136 * @param inputStream InputStream to wrap.
137 * @param encode true if we should encode all data read from us, false if we should decode.
138 * @param lineLength If doEncode is true, each line of encoded data will contain lineLength characters (rounded down to the nearest multiple of 4). If
139 * lineLength <= 0, the encoded data is not divided into lines. If doEncode is false, lineLength is ignored.
140 * @param lineSeparator If doEncode is true, each line of encoded data will be terminated with this byte sequence (for example \r\n). If lineLength <=
141 * 0, the lineSeparator is not used. If doEncode is false lineSeparator is ignored.
142 * @param decodingPolicy The decoding policy.
143 * @since 1.15
144 * @deprecated Use {@link #builder()} and {@link Builder}.
145 */
146 @Deprecated
147 public Base32InputStream(final InputStream inputStream, final boolean encode, final int lineLength, final byte[] lineSeparator,
148 final CodecPolicy decodingPolicy) {
149 super(builder().setInputStream(inputStream).setEncode(encode)
150 .setBaseNCodec(Base32.builder().setLineLength(lineLength).setLineSeparator(lineSeparator).setDecodingPolicy(decodingPolicy).get()));
151 }
152 }