    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.InputStream;
    021
    022import org.apache.commons.codec.CodecPolicy;
    023import org.apache.commons.codec.binary.BaseNCodecInputStream.AbstracBuilder; // NOPMD: Required by ECJ (Eclipse)
    024
    025/**
    026 * Provides Base32 decoding 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 Base32InputStream is to DECODE, whereas the default behavior of the Base32OutputStream is to ENCODE, but this behavior can be
    030 * overridden by using a different constructor.
    031 * </p>
    032 * <p>
    033 * Since this class operates directly on byte streams, and not character streams, it is hard-coded to only encode/decode character encodings which are
    034 * compatible with the lower 127 ASCII chart (ISO-8859-1, Windows-1252, UTF-8, etc).
    035 * </p>
    036 * <p>
    037 * 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
    038 * unused from the final character or entire characters. The default mode is lenient decoding.
    039 * </p>
    040 * <ul>
    041 * <li>Lenient: Any trailing bits are composed into 8-bit bytes where possible. The remainder are discarded.</li>
    042 * <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
    043 * character must be zero. Impossible counts of entire final characters are not allowed.</li>
    044 * </ul>
    045 * <p>
    046 * 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
    047 * the final character. This requires that the input bytes use the same padding and alphabet as the encoder.
    048 * </p>
    049 *
    050 * @see Base32
    051 * @see <a href="https://www.ietf.org/rfc/rfc4648.txt">RFC 4648</a>
    052 * @since 1.5
    053 */
    054public class Base32InputStream extends BaseNCodecInputStream<Base32, Base32InputStream, Base32InputStream.Builder> {
    055
    056    /**
    057     * Builds instances of Base32InputStream.
    058     *
    059     * @since 1.20.0
    060     */
    061    public static class Builder extends AbstracBuilder<Base32InputStream, Base32, Builder> {
    062
    063        /**
    064         * Constructs a new instance.
    065         */
    066        public Builder() {
    067            // empty
    068        }
    069
    070        @Override
    071        public Base32InputStream get() {
    072            return new Base32InputStream(this);
    073        }
    074
    075        @Override
    076        protected Base32 newBaseNCodec() {
    077            return new Base32();
    078        }
    079    }
    080
    081    /**
    082     * Constructs a new Builder.
    083     *
    084     * @return a new Builder.
    085     * @since 1.20.0
    086     */
    087    public static Builder builder() {
    088        return new Builder();
    089    }
    090
    091    private Base32InputStream(final Builder builder) {
    092        super(builder);
    093    }
    094
    095    /**
    096     * Constructs a Base32InputStream such that all data read is Base32-decoded from the original provided InputStream.
    097     *
    098     * @param inputStream InputStream to wrap.
    099     */
    100    public Base32InputStream(final InputStream inputStream) {
    101        super(builder().setInputStream(inputStream));
    102    }
    103
    104    /**
    105     * Constructs a Base32InputStream such that all data read is either Base32-encoded or Base32-decoded from the original provided InputStream.
    106     *
    107     * @param inputStream InputStream to wrap.
    108     * @param encode    true if we should encode all data read from us, false if we should decode.
    109     * @deprecated Use {@link #builder()} and {@link Builder}.
    110     */
    111    @Deprecated
    112    public Base32InputStream(final InputStream inputStream, final boolean encode) {
    113        super(builder().setInputStream(inputStream).setEncode(encode));
    114    }
    115
    116    /**
    117     * Constructs a Base32InputStream such that all data read is either Base32-encoded or Base32-decoded from the original provided InputStream.
    118     *
    119     * @param inputStream   InputStream to wrap.
    120     * @param encode      true if we should encode all data read from us, false if we should decode.
    121     * @param lineLength    If doEncode is true, each line of encoded data will contain lineLength characters (rounded down to the nearest multiple of 4). If
    122     *                      lineLength &lt;= 0, the encoded data is not divided into lines. If doEncode is false, lineLength is ignored.
    123     * @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,
    124     *                      the lineSeparator is not used. If doEncode is false lineSeparator is ignored.
    125     * @deprecated Use {@link #builder()} and {@link Builder}.
    126     */
    127    @Deprecated
    128    public Base32InputStream(final InputStream inputStream, final boolean encode, final int lineLength, final byte[] lineSeparator) {
    129        super(builder().setInputStream(inputStream).setEncode(encode)
    130                .setBaseNCodec(Base32.builder().setLineLength(lineLength).setLineSeparator(lineSeparator).get()));
    131    }
    132
    133    /**
    134     * Constructs a Base32InputStream such that all data read is either Base32-encoded or Base32-decoded from the original provided InputStream.
    135     *
    136     * @param inputStream    InputStream to wrap.
    137     * @param encode       true if we should encode all data read from us, false if we should decode.
    138     * @param lineLength     If doEncode is true, each line of encoded data will contain lineLength characters (rounded down to the nearest multiple of 4). If
    139     *                       lineLength &lt;= 0, the encoded data is not divided into lines. If doEncode is false, lineLength is ignored.
    140     * @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;=
    141     *                       0, the lineSeparator is not used. If doEncode is false lineSeparator is ignored.
    142     * @param decodingPolicy The decoding policy.
    143     * @since 1.15
    144     * @deprecated Use {@link #builder()} and {@link Builder}.
    145     */
    146    @Deprecated
    147    public Base32InputStream(final InputStream inputStream, final boolean encode, final int lineLength, final byte[] lineSeparator,
    148            final CodecPolicy decodingPolicy) {
    149        super(builder().setInputStream(inputStream).setEncode(encode)
    150                .setBaseNCodec(Base32.builder().setLineLength(lineLength).setLineSeparator(lineSeparator).setDecodingPolicy(decodingPolicy).get()));
    151    }
    152}