    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.net;
    019
    020import java.io.UnsupportedEncodingException;
    021import java.nio.charset.Charset;
    022import java.nio.charset.StandardCharsets;
    023import java.nio.charset.UnsupportedCharsetException;
    024import java.util.BitSet;
    025
    026import org.apache.commons.codec.DecoderException;
    027import org.apache.commons.codec.EncoderException;
    028import org.apache.commons.codec.StringDecoder;
    029import org.apache.commons.codec.StringEncoder;
    030
    031/**
    032 * Similar to the Quoted-Printable content-transfer-encoding defined in
    033 * <a href="https://www.ietf.org/rfc/rfc1521.txt">RFC 1521</a> and designed to allow text containing mostly ASCII
    034 * characters to be decipherable on an ASCII terminal without decoding.
    035 * <p>
    036 * <a href="https://www.ietf.org/rfc/rfc1522.txt">RFC 1522</a> describes techniques to allow the encoding of non-ASCII
    037 * text in various portions of a RFC 822 [2] message header, in a manner which is unlikely to confuse existing message
    038 * handling software.
    039 * </p>
    040 * <p>
    041 * This class is conditionally thread-safe.
    042 * The instance field for encoding blanks is mutable {@link #setEncodeBlanks(boolean)}
    043 * but is not volatile, and accesses are not synchronized.
    044 * If an instance of the class is shared between threads, the caller needs to ensure that suitable synchronization
    045 * is used to ensure safe publication of the value between threads, and must not invoke
    046 * {@link #setEncodeBlanks(boolean)} after initial setup.
    047 * </p>
    048 *
    049 * @see <a href="https://www.ietf.org/rfc/rfc1522.txt">MIME (Multipurpose Internet Mail Extensions) Part Two: Message
    050 *          Header Extensions for Non-ASCII Text</a>
    051 *
    052 * @since 1.3
    053 */
    054public class QCodec extends RFC1522Codec implements StringEncoder, StringDecoder {
    055
    056    /**
    057     * BitSet of printable characters as defined in RFC 1522.
    058     */
    059    private static final BitSet PRINTABLE_CHARS = new BitSet(256);
    060
    061    // Static initializer for printable chars collection
    062    static {
    063        // alpha characters
    064        PRINTABLE_CHARS.set(' ');
    065        PRINTABLE_CHARS.set('!');
    066        PRINTABLE_CHARS.set('"');
    067        PRINTABLE_CHARS.set('#');
    068        PRINTABLE_CHARS.set('$');
    069        PRINTABLE_CHARS.set('%');
    070        PRINTABLE_CHARS.set('&');
    071        PRINTABLE_CHARS.set('\'');
    072        PRINTABLE_CHARS.set('(');
    073        PRINTABLE_CHARS.set(')');
    074        PRINTABLE_CHARS.set('*');
    075        PRINTABLE_CHARS.set('+');
    076        PRINTABLE_CHARS.set(',');
    077        PRINTABLE_CHARS.set('-');
    078        PRINTABLE_CHARS.set('.');
    079        PRINTABLE_CHARS.set('/');
    080        for (int i = '0'; i <= '9'; i++) {
    081            PRINTABLE_CHARS.set(i);
    082        }
    083        PRINTABLE_CHARS.set(':');
    084        PRINTABLE_CHARS.set(';');
    085        PRINTABLE_CHARS.set('<');
    086        PRINTABLE_CHARS.set('>');
    087        PRINTABLE_CHARS.set('@');
    088        for (int i = 'A'; i <= 'Z'; i++) {
    089            PRINTABLE_CHARS.set(i);
    090        }
    091        PRINTABLE_CHARS.set('[');
    092        PRINTABLE_CHARS.set('\\');
    093        PRINTABLE_CHARS.set(']');
    094        PRINTABLE_CHARS.set('^');
    095        PRINTABLE_CHARS.set('`');
    096        for (int i = 'a'; i <= 'z'; i++) {
    097            PRINTABLE_CHARS.set(i);
    098        }
    099        PRINTABLE_CHARS.set('{');
    100        PRINTABLE_CHARS.set('|');
    101        PRINTABLE_CHARS.set('}');
    102        PRINTABLE_CHARS.set('~');
    103    }
    104    private static final byte SPACE = 32;
    105
    106    private static final byte UNDERSCORE = 95;
    107
    108    private boolean encodeBlanks;
    109
    110    /**
    111     * Default constructor.
    112     */
    113    public QCodec() {
    114        this(StandardCharsets.UTF_8);
    115    }
    116
    117    /**
    118     * Constructor which allows for the selection of a default Charset.
    119     *
    120     * @param charset
    121     *            the default string Charset to use.
    122     *
    123     * @see Charset
    124     * @since 1.7
    125     */
    126    public QCodec(final Charset charset) {
    127        super(charset);
    128    }
    129
    130    /**
    131     * Constructor which allows for the selection of a default Charset.
    132     *
    133     * @param charsetName
    134     *            the Charset to use.
    135     * @throws java.nio.charset.UnsupportedCharsetException
    136     *             If the named Charset is unavailable.
    137     * @since 1.7 throws UnsupportedCharsetException if the named Charset is unavailable
    138     * @see Charset
    139     */
    140    public QCodec(final String charsetName) {
    141        this(Charset.forName(charsetName));
    142    }
    143
    144    /**
    145     * Decodes a quoted-printable object into its original form. Escaped characters are converted back to their original
    146     * representation.
    147     *
    148     * @param obj
    149     *            quoted-printable object to convert into its original form.
    150     * @return original object.
    151     * @throws DecoderException
    152     *             Thrown if the argument is not a {@code String}. Thrown if a failure condition is encountered
    153     *             during the decode process.
    154     */
    155    @Override
    156    public Object decode(final Object obj) throws DecoderException {
    157        if (obj == null) {
    158            return null;
    159        }
    160        if (obj instanceof String) {
    161            return decode((String) obj);
    162        }
    163        throw new DecoderException("Objects of type " + obj.getClass().getName() + " cannot be decoded using Q codec");
    164    }
    165
    166    /**
    167     * Decodes a quoted-printable string into its original form. Escaped characters are converted back to their original
    168     * representation.
    169     *
    170     * @param str
    171     *            quoted-printable string to convert into its original form.
    172     * @return original string.
    173     * @throws DecoderException
    174     *             A decoder exception is thrown if a failure condition is encountered during the decode process.
    175     */
    176    @Override
    177    public String decode(final String str) throws DecoderException {
    178        try {
    179            return decodeText(str);
    180        } catch (final UnsupportedEncodingException e) {
    181            throw new DecoderException(e.getMessage(), e);
    182        }
    183    }
    184
    185    @Override
    186    protected byte[] doDecoding(final byte[] bytes) throws DecoderException {
    187        if (bytes == null) {
    188            return null;
    189        }
    190        boolean hasUnderscores = false;
    191        for (final byte b : bytes) {
    192            if (b == UNDERSCORE) {
    193                hasUnderscores = true;
    194                break;
    195            }
    196        }
    197        if (hasUnderscores) {
    198            final byte[] tmp = new byte[bytes.length];
    199            for (int i = 0; i < bytes.length; i++) {
    200                final byte b = bytes[i];
    201                if (b != UNDERSCORE) {
    202                    tmp[i] = b;
    203                } else {
    204                    tmp[i] = SPACE;
    205                }
    206            }
    207            return QuotedPrintableCodec.decodeQuotedPrintable(tmp);
    208        }
    209        return QuotedPrintableCodec.decodeQuotedPrintable(bytes);
    210    }
    211
    212    @Override
    213    protected byte[] doEncoding(final byte[] bytes) {
    214        if (bytes == null) {
    215            return null;
    216        }
    217        final byte[] data = QuotedPrintableCodec.encodeQuotedPrintable(PRINTABLE_CHARS, bytes);
    218        if (this.encodeBlanks) {
    219            for (int i = 0; i < data.length; i++) {
    220                if (data[i] == SPACE) {
    221                    data[i] = UNDERSCORE;
    222                }
    223            }
    224        }
    225        return data;
    226    }
    227
    228    /**
    229     * Encodes an object into its quoted-printable form using the default Charset. Unsafe characters are escaped.
    230     *
    231     * @param obj
    232     *            object to convert to quoted-printable form.
    233     * @return quoted-printable object.
    234     * @throws EncoderException
    235     *             thrown if a failure condition is encountered during the encoding process.
    236     */
    237    @Override
    238    public Object encode(final Object obj) throws EncoderException {
    239        if (obj == null) {
    240            return null;
    241        }
    242        if (obj instanceof String) {
    243            return encode((String) obj);
    244        }
    245        throw new EncoderException("Objects of type " + obj.getClass().getName() + " cannot be encoded using Q codec");
    246    }
    247
    248    /**
    249     * Encodes a string into its quoted-printable form using the default Charset. Unsafe characters are escaped.
    250     *
    251     * @param sourceStr
    252     *            string to convert to quoted-printable form.
    253     * @return quoted-printable string.
    254     * @throws EncoderException
    255     *             thrown if a failure condition is encountered during the encoding process.
    256     */
    257    @Override
    258    public String encode(final String sourceStr) throws EncoderException {
    259        return encode(sourceStr, getCharset());
    260    }
    261
    262    /**
    263     * Encodes a string into its quoted-printable form using the specified Charset. Unsafe characters are escaped.
    264     *
    265     * @param sourceStr
    266     *            string to convert to quoted-printable form.
    267     * @param sourceCharset
    268     *            the Charset for sourceStr.
    269     * @return quoted-printable string.
    270     * @throws EncoderException
    271     *             thrown if a failure condition is encountered during the encoding process.
    272     * @since 1.7
    273     */
    274    public String encode(final String sourceStr, final Charset sourceCharset) throws EncoderException {
    275        return encodeText(sourceStr, sourceCharset);
    276    }
    277
    278    /**
    279     * Encodes a string into its quoted-printable form using the specified Charset. Unsafe characters are escaped.
    280     *
    281     * @param sourceStr
    282     *            string to convert to quoted-printable form.
    283     * @param sourceCharset
    284     *            the Charset for sourceStr.
    285     * @return quoted-printable string.
    286     * @throws EncoderException
    287     *             thrown if a failure condition is encountered during the encoding process.
    288     */
    289    public String encode(final String sourceStr, final String sourceCharset) throws EncoderException {
    290        try {
    291            return encodeText(sourceStr, sourceCharset);
    292        } catch (final UnsupportedCharsetException e) {
    293            throw new EncoderException(e.getMessage(), e);
    294        }
    295    }
    296
    297    @Override
    298    protected String getEncoding() {
    299        return "Q";
    300    }
    301
    302    /**
    303     * Tests if optional transformation of SPACE characters is to be used
    304     *
    305     * @return {@code true} if SPACE characters are to be transformed, {@code false} otherwise.
    306     */
    307    public boolean isEncodeBlanks() {
    308        return this.encodeBlanks;
    309    }
    310
    311    /**
    312     * Defines whether optional transformation of SPACE characters is to be used
    313     *
    314     * @param b
    315     *            {@code true} if SPACE characters are to be transformed, {@code false} otherwise.
    316     */
    317    public void setEncodeBlanks(final boolean b) {
    318        this.encodeBlanks = b;
    319    }
    320}