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.OutputStream;
21
22 import org.apache.commons.codec.CodecPolicy;
23 import org.apache.commons.codec.binary.BaseNCodecOutputStream.AbstractBuilder; // NOPMD: Required by ECJ (Eclipse)
24
25 /**
26 * Provides Base64 encoding 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 Base64OutputStream is to ENCODE, whereas the default behavior of the Base64InputStream is to DECODE. But this behavior can be
30 * overridden by using a different constructor.
31 * </p>
32 * <p>
33 * This class implements section <cite>6.8. Base64 Content-Transfer-Encoding</cite> from RFC 2045 <cite>Multipurpose Internet Mail Extensions (MIME) Part One:
34 * Format of Internet Message Bodies</cite> by Freed and Borenstein.
35 * </p>
36 * <p>
37 * Since this class operates directly on byte streams, and not character streams, it is hard-coded to only encode/decode character encodings which are
38 * compatible with the lower 127 ASCII chart (ISO-8859-1, Windows-1252, UTF-8, etc).
39 * </p>
40 * <p>
41 * <strong>Note:</strong> It is mandatory to close the stream after the last byte has been written to it, otherwise the final padding will be omitted and the
42 * resulting data will be incomplete/inconsistent.
43 * </p>
44 * <p>
45 * 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
46 * unused from the final character or entire characters. The default mode is lenient decoding.
47 * </p>
48 * <ul>
49 * <li>Lenient: Any trailing bits are composed into 8-bit bytes where possible. The remainder are discarded.
50 * <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
51 * character must be zero. Impossible counts of entire final characters are not allowed.
52 * </ul>
53 * <p>
54 * 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
55 * the final character. This requires that the input bytes use the same padding and alphabet as the encoder.
56 * </p>
57 *
58 * @see Base64
59 * @see <a href="https://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>
60 * @since 1.4
61 */
62 public class Base64OutputStream extends BaseNCodecOutputStream<Base64, Base64OutputStream, Base64OutputStream.Builder> {
63
64 /**
65 * Builds instances of Base32InputStream.
66 *
67 * @since 1.20.0
68 */
69 public static class Builder extends AbstractBuilder<Base64OutputStream, Base64, Builder> {
70
71 /**
72 * Constructs a new instance.
73 */
74 public Builder() {
75 setEncode(true);
76 }
77
78 @Override
79 public Base64OutputStream get() {
80 return new Base64OutputStream(this);
81 }
82
83 @Override
84 protected Base64 newBaseNCodec() {
85 return new Base64();
86 }
87 }
88
89 /**
90 * Constructs a new Builder.
91 *
92 * @return a new Builder.
93 */
94 public static Builder builder() {
95 return new Builder();
96 }
97
98 private Base64OutputStream(final Builder builder) {
99 super(builder);
100 }
101
102 /**
103 * Constructs a Base64OutputStream such that all data written is Base64-encoded to the original provided OutputStream.
104 *
105 * @param outputStream OutputStream to wrap.
106 */
107 public Base64OutputStream(final OutputStream outputStream) {
108 this(builder().setOutputStream(outputStream));
109 }
110
111 /**
112 * Constructs a Base64OutputStream such that all data written is either Base64-encoded or Base64-decoded to the original provided OutputStream.
113 *
114 * @param outputStream OutputStream to wrap.
115 * @param encode true if we should encode all data written to us, false if we should decode.
116 * @deprecated Use {@link #builder()} and {@link Builder}.
117 */
118 @Deprecated
119 public Base64OutputStream(final OutputStream outputStream, final boolean encode) {
120 super(builder().setOutputStream(outputStream).setEncode(encode));
121 }
122
123 /**
124 * Constructs a Base64OutputStream such that all data written is either Base64-encoded or Base64-decoded to the original provided OutputStream.
125 *
126 * @param outputStream OutputStream to wrap.
127 * @param encode true if we should encode all data written to us, false if we should decode.
128 * @param lineLength If doEncode is true, each line of encoded data will contain lineLength characters (rounded down to the nearest multiple of 4). If
129 * lineLength <= 0, the encoded data is not divided into lines. If doEncode is false, lineLength is ignored.
130 * @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,
131 * the lineSeparator is not used. If doEncode is false lineSeparator is ignored.
132 * @deprecated Use {@link #builder()} and {@link Builder}.
133 */
134 @Deprecated
135 public Base64OutputStream(final OutputStream outputStream, final boolean encode, final int lineLength, final byte[] lineSeparator) {
136 super(builder().setOutputStream(outputStream).setEncode(encode)
137 .setBaseNCodec(Base64.builder().setLineLength(lineLength).setLineSeparator(lineSeparator).get()));
138 }
139
140 /**
141 * Constructs a Base64OutputStream such that all data written is either Base64-encoded or Base64-decoded to the original provided OutputStream.
142 *
143 * @param outputStream OutputStream to wrap.
144 * @param encode true if we should encode all data written to us, false if we should decode.
145 * @param lineLength If doEncode is true, each line of encoded data will contain lineLength characters (rounded down to the nearest multiple of 4). If
146 * lineLength <= 0, the encoded data is not divided into lines. If doEncode is false, lineLength is ignored.
147 * @param lineSeparator If doEncode is true, each line of encoded data will be terminated with this byte sequence (for example \r\n). If lineLength <=
148 * 0, the lineSeparator is not used. If doEncode is false lineSeparator is ignored.
149 * @param decodingPolicy The decoding policy.
150 * @since 1.15
151 * @deprecated Use {@link #builder()} and {@link Builder}.
152 */
153 @Deprecated
154 public Base64OutputStream(final OutputStream outputStream, final boolean encode, final int lineLength, final byte[] lineSeparator,
155 final CodecPolicy decodingPolicy) {
156 super(builder().setOutputStream(outputStream).setEncode(encode)
157 .setBaseNCodec(Base64.builder().setLineLength(lineLength).setLineSeparator(lineSeparator).setDecodingPolicy(decodingPolicy).get()));
158 }
159 }