    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 $Id$
    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
    079     *            is 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}