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
18 package org.apache.commons.codec.binary;
19
20 import java.io.OutputStream;
21
22 /**
23 * Provides Base64 encoding and decoding in a streaming fashion (unlimited size). When encoding the default lineLength
24 * is 76 characters and the default lineEnding is CRLF, but these can be overridden by using the appropriate
25 * constructor.
26 * <p>
27 * The default behaviour of the Base64OutputStream is to ENCODE, whereas the default behaviour of the Base64InputStream
28 * is to DECODE. But this behaviour can be overridden by using a different constructor.
29 * </p>
30 * <p>
31 * This class implements section <cite>6.8. Base64 Content-Transfer-Encoding</cite> from RFC 2045 <cite>Multipurpose
32 * Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies</cite> by Freed and Borenstein.
33 * </p>
34 * <p>
35 * Since this class operates directly on byte streams, and not character streams, it is hard-coded to only encode/decode
36 * character encodings which are compatible with the lower 127 ASCII chart (ISO-8859-1, Windows-1252, UTF-8, etc).
37 * </p>
38 * <p>
39 * <b>Note:</b> It is mandatory to close the stream after the last byte has been written to it, otherwise the
40 * final padding will be omitted and the resulting data will be incomplete/inconsistent.
41 * </p>
42 *
43 * @version $Id: Base64OutputStream.java 1635952 2014-11-01 14:19:04Z tn $
44 * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>
45 * @since 1.4
46 */
47 public class Base64OutputStream extends BaseNCodecOutputStream {
48
49 /**
50 * Creates a Base64OutputStream such that all data written is Base64-encoded to the original provided OutputStream.
51 *
52 * @param out
53 * OutputStream to wrap.
54 */
55 public Base64OutputStream(final OutputStream out) {
56 this(out, true);
57 }
58
59 /**
60 * Creates a Base64OutputStream such that all data written is either Base64-encoded or Base64-decoded to the
61 * original provided OutputStream.
62 *
63 * @param out
64 * OutputStream to wrap.
65 * @param doEncode
66 * true if we should encode all data written to us, false if we should decode.
67 */
68 public Base64OutputStream(final OutputStream out, final boolean doEncode) {
69 super(out,new Base64(false), doEncode);
70 }
71
72 /**
73 * Creates a Base64OutputStream such that all data written is either Base64-encoded or Base64-decoded to the
74 * original provided OutputStream.
75 *
76 * @param out
77 * OutputStream to wrap.
78 * @param doEncode
79 * true if we should encode all data written to us, false if we should decode.
80 * @param lineLength
81 * If doEncode is true, each line of encoded data will contain lineLength characters (rounded down to
82 * nearest multiple of 4). If lineLength <= 0, the encoded data is not divided into lines. If doEncode
83 * is false, lineLength is ignored.
84 * @param lineSeparator
85 * If doEncode is true, each line of encoded data will be terminated with this byte sequence (e.g. \r\n).
86 * If lineLength <= 0, the lineSeparator is not used. If doEncode is false lineSeparator is ignored.
87 */
88 public Base64OutputStream(final OutputStream out, final boolean doEncode,
89 final int lineLength, final byte[] lineSeparator) {
90 super(out, new Base64(lineLength, lineSeparator), doEncode);
91 }
92 }