001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.commons.codec.binary;
019
020import java.io.InputStream;
021
022/**
023 * Provides Base64 encoding and decoding in a streaming fashion (unlimited size). When encoding the default lineLength
024 * is 76 characters and the default lineEnding is CRLF, but these can be overridden by using the appropriate
025 * constructor.
026 * <p>
027 * The default behaviour of the Base64InputStream is to DECODE, whereas the default behaviour of the Base64OutputStream
028 * is to ENCODE, but this behaviour can be overridden by using a different constructor.
029 * </p>
030 * <p>
031 * This class implements section <cite>6.8. Base64 Content-Transfer-Encoding</cite> from RFC 2045 <cite>Multipurpose
032 * Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies</cite> by Freed and Borenstein.
033 * </p>
034 * <p>
035 * Since this class operates directly on byte streams, and not character streams, it is hard-coded to only encode/decode
036 * character encodings which are compatible with the lower 127 ASCII chart (ISO-8859-1, Windows-1252, UTF-8, etc).
037 * </p>
038 *
039 * @version $Id: Base64InputStream.java 1563226 2014-01-31 19:38:06Z ggregory $
040 * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>
041 * @since 1.4
042 */
043public class Base64InputStream extends BaseNCodecInputStream {
044
045    /**
046     * Creates a Base64InputStream such that all data read is Base64-decoded from the original provided InputStream.
047     *
048     * @param in
049     *            InputStream to wrap.
050     */
051    public Base64InputStream(final InputStream in) {
052        this(in, false);
053    }
054
055    /**
056     * Creates a Base64InputStream such that all data read is either Base64-encoded or Base64-decoded from the original
057     * provided InputStream.
058     *
059     * @param in
060     *            InputStream to wrap.
061     * @param doEncode
062     *            true if we should encode all data read from us, false if we should decode.
063     */
064    public Base64InputStream(final InputStream in, final boolean doEncode) {
065        super(in, new Base64(false), doEncode);
066    }
067
068    /**
069     * Creates a Base64InputStream such that all data read is either Base64-encoded or Base64-decoded from the original
070     * provided InputStream.
071     *
072     * @param in
073     *            InputStream to wrap.
074     * @param doEncode
075     *            true if we should encode all data read from us, false if we should decode.
076     * @param lineLength
077     *            If doEncode is true, each line of encoded data will contain lineLength characters (rounded down to
078     *            nearest multiple of 4). If lineLength &lt;= 0, the encoded data is not divided into lines. If doEncode is
079     *            false, lineLength is ignored.
080     * @param lineSeparator
081     *            If doEncode is true, each line of encoded data will be terminated with this byte sequence (e.g. \r\n).
082     *            If lineLength &lt;= 0, the lineSeparator is not used. If doEncode is false lineSeparator is ignored.
083     */
084    public Base64InputStream(final InputStream in, final boolean doEncode,
085                             final int lineLength, final byte[] lineSeparator) {
086        super(in, new Base64(lineLength, lineSeparator), doEncode);
087    }
088}