    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 *      https://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.OutputStream;
    021
    022import org.apache.commons.codec.CodecPolicy;
    023import org.apache.commons.codec.binary.BaseNCodecOutputStream.AbstractBuilder; // NOPMD: Required by ECJ (Eclipse)
    024
    025/**
    026 * Provides Base64 encoding in a streaming fashion (unlimited size). When encoding the default lineLength is 76 characters and the default lineEnding is CRLF,
    027 * but these can be overridden by using the appropriate constructor.
    028 * <p>
    029 * The default behavior of the Base64OutputStream is to ENCODE, whereas the default behavior of the Base64InputStream is to DECODE. But this behavior can be
    030 * overridden by using a different constructor.
    031 * </p>
    032 * <p>
    033 * This class implements section <cite>6.8. Base64 Content-Transfer-Encoding</cite> from RFC 2045 <cite>Multipurpose Internet Mail Extensions (MIME) Part One:
    034 * Format of Internet Message Bodies</cite> by Freed and Borenstein.
    035 * </p>
    036 * <p>
    037 * Since this class operates directly on byte streams, and not character streams, it is hard-coded to only encode/decode character encodings which are
    038 * compatible with the lower 127 ASCII chart (ISO-8859-1, Windows-1252, UTF-8, etc).
    039 * </p>
    040 * <p>
    041 * <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
    042 * resulting data will be incomplete/inconsistent.
    043 * </p>
    044 * <p>
    045 * 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
    046 * unused from the final character or entire characters. The default mode is lenient decoding.
    047 * </p>
    048 * <ul>
    049 * <li>Lenient: Any trailing bits are composed into 8-bit bytes where possible. The remainder are discarded.
    050 * <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
    051 * character must be zero. Impossible counts of entire final characters are not allowed.
    052 * </ul>
    053 * <p>
    054 * 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
    055 * the final character. This requires that the input bytes use the same padding and alphabet as the encoder.
    056 * </p>
    057 *
    058 * @see Base64
    059 * @see <a href="https://www.ietf.org/rfc/rfc2045.txt">RFC 2045</a>
    060 * @since 1.4
    061 */
    062public class Base64OutputStream extends BaseNCodecOutputStream<Base64, Base64OutputStream, Base64OutputStream.Builder> {
    063
    064    /**
    065     * Builds instances of Base32InputStream.
    066     *
    067     * @since 1.20.0
    068     */
    069    public static class Builder extends AbstractBuilder<Base64OutputStream, Base64, Builder> {
    070
    071        /**
    072         * Constructs a new instance.
    073         */
    074        public Builder() {
    075            setEncode(true);
    076        }
    077
    078        @Override
    079        public Base64OutputStream get() {
    080            return new Base64OutputStream(this);
    081        }
    082
    083        @Override
    084        protected Base64 newBaseNCodec() {
    085            return new Base64();
    086        }
    087    }
    088
    089    /**
    090     * Constructs a new Builder.
    091     *
    092     * @return a new Builder.
    093     */
    094    public static Builder builder() {
    095        return new Builder();
    096    }
    097
    098    private Base64OutputStream(final Builder builder) {
    099        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 &lt;= 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 &lt;= 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 &lt;= 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 &lt;=
    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}