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.
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.
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}