Source code
Description: source: package: org.apache.commons.codec.net, class: QCodec

    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 UNDERSCORE = 95;
    105
    106    private boolean encodeBlanks;
    107
    108    /**
    109     * Constructs a new instance.
    110     */
    111    public QCodec() {
    112        this(StandardCharsets.UTF_8);
    113    }
    114
    115    /**
    116     * Constructs a new instance for the selection of a default Charset.
    117     *
    118     * @param charset
    119     *            the default string Charset to use.
    120     *
    121     * @see Charset
    122     * @since 1.7
    123     */
    124    public QCodec(final Charset charset) {
    125        super(charset);
    126    }
    127
    128    /**
    129     * Constructs a new instance for the selection of a default Charset.
    130     *
    131     * @param charsetName
    132     *            the Charset to use.
    133     * @throws java.nio.charset.UnsupportedCharsetException
    134     *             If the named Charset is unavailable.
    135     * @since 1.7 throws UnsupportedCharsetException if the named Charset is unavailable
    136     * @see Charset
    137     */
    138    public QCodec(final String charsetName) {
    139        this(Charset.forName(charsetName));
    140    }
    141
    142    /**
    143     * Decodes a quoted-printable object into its original form. Escaped characters are converted back to their original
    144     * representation.
    145     *
    146     * @param obj
    147     *            quoted-printable object to convert into its original form.
    148     * @return original object.
    149     * @throws DecoderException
    150     *             Thrown if the argument is not a {@code String}. Thrown if a failure condition is encountered
    151     *             during the decode process.
    152     */
    153    @Override
    154    public Object decode(final Object obj) throws DecoderException {
    155        if (obj == null) {
    156            return null;
    157        }
    158        if (obj instanceof String) {
    159            return decode((String) obj);
    160        }
    161        throw new DecoderException("Objects of type " + obj.getClass().getName() + " cannot be decoded using Q codec");
    162    }
    163
    164    /**
    165     * Decodes a quoted-printable string into its original form. Escaped characters are converted back to their original
    166     * representation.
    167     *
    168     * @param str
    169     *            quoted-printable string to convert into its original form.
    170     * @return original string.
    171     * @throws DecoderException
    172     *             A decoder exception is thrown if a failure condition is encountered during the decode process.
    173     */
    174    @Override
    175    public String decode(final String str) throws DecoderException {
    176        try {
    177            return decodeText(str);
    178        } catch (final UnsupportedEncodingException e) {
    179            throw new DecoderException(e.getMessage(), e);
    180        }
    181    }
    182
    183    @Override
    184    protected byte[] doDecoding(final byte[] bytes) throws DecoderException {
    185        if (bytes == null) {
    186            return null;
    187        }
    188        boolean hasUnderscores = false;
    189        for (final byte b : bytes) {
    190            if (b == UNDERSCORE) {
    191                hasUnderscores = true;
    192                break;
    193            }
    194        }
    195        if (hasUnderscores) {
    196            final byte[] tmp = new byte[bytes.length];
    197            for (int i = 0; i < bytes.length; i++) {
    198                final byte b = bytes[i];
    199                if (b != UNDERSCORE) {
    200                    tmp[i] = b;
    201                } else {
    202                    tmp[i] = Utils.SPACE;
    203                }
    204            }
    205            return QuotedPrintableCodec.decodeQuotedPrintable(tmp);
    206        }
    207        return QuotedPrintableCodec.decodeQuotedPrintable(bytes);
    208    }
    209
    210    @Override
    211    protected byte[] doEncoding(final byte[] bytes) {
    212        if (bytes == null) {
    213            return null;
    214        }
    215        final byte[] data = QuotedPrintableCodec.encodeQuotedPrintable(PRINTABLE_CHARS, bytes);
    216        if (this.encodeBlanks) {
    217            for (int i = 0; i < data.length; i++) {
    218                if (data[i] == Utils.SPACE) {
    219                    data[i] = UNDERSCORE;
    220                }
    221            }
    222        }
    223        return data;
    224    }
    225
    226    /**
    227     * Encodes an object into its quoted-printable form using the default Charset. Unsafe characters are escaped.
    228     *
    229     * @param obj
    230     *            object to convert to quoted-printable form.
    231     * @return quoted-printable object.
    232     * @throws EncoderException
    233     *             thrown if a failure condition is encountered during the encoding process.
    234     */
    235    @Override
    236    public Object encode(final Object obj) throws EncoderException {
    237        if (obj == null) {
    238            return null;
    239        }
    240        if (obj instanceof String) {
    241            return encode((String) obj);
    242        }
    243        throw new EncoderException("Objects of type " + obj.getClass().getName() + " cannot be encoded using Q codec");
    244    }
    245
    246    /**
    247     * Encodes a string into its quoted-printable form using the default Charset. Unsafe characters are escaped.
    248     *
    249     * @param sourceStr
    250     *            string to convert to quoted-printable form.
    251     * @return quoted-printable string.
    252     * @throws EncoderException
    253     *             thrown if a failure condition is encountered during the encoding process.
    254     */
    255    @Override
    256    public String encode(final String sourceStr) throws EncoderException {
    257        return encode(sourceStr, getCharset());
    258    }
    259
    260    /**
    261     * Encodes a string into its quoted-printable form using the specified Charset. Unsafe characters are escaped.
    262     *
    263     * @param sourceStr
    264     *            string to convert to quoted-printable form.
    265     * @param sourceCharset
    266     *            the Charset for sourceStr.
    267     * @return quoted-printable string.
    268     * @throws EncoderException
    269     *             thrown if a failure condition is encountered during the encoding process.
    270     * @since 1.7
    271     */
    272    public String encode(final String sourceStr, final Charset sourceCharset) throws EncoderException {
    273        return encodeText(sourceStr, sourceCharset);
    274    }
    275
    276    /**
    277     * Encodes a string into its quoted-printable form using the specified Charset. Unsafe characters are escaped.
    278     *
    279     * @param sourceStr
    280     *            string to convert to quoted-printable form.
    281     * @param sourceCharset
    282     *            the Charset for sourceStr.
    283     * @return quoted-printable string.
    284     * @throws EncoderException
    285     *             thrown if a failure condition is encountered during the encoding process.
    286     */
    287    public String encode(final String sourceStr, final String sourceCharset) throws EncoderException {
    288        try {
    289            return encodeText(sourceStr, sourceCharset);
    290        } catch (final UnsupportedCharsetException e) {
    291            throw new EncoderException(e.getMessage(), e);
    292        }
    293    }
    294
    295    @Override
    296    protected String getEncoding() {
    297        return "Q";
    298    }
    299
    300    /**
    301     * Tests if optional transformation of SPACE characters is to be used
    302     *
    303     * @return {@code true} if SPACE characters are to be transformed, {@code false} otherwise.
    304     */
    305    public boolean isEncodeBlanks() {
    306        return this.encodeBlanks;
    307    }
    308
    309    /**
    310     * Defines whether optional transformation of SPACE characters is to be used
    311     *
    312     * @param b
    313     *            {@code true} if SPACE characters are to be transformed, {@code false} otherwise.
    314     */
    315    public void setEncodeBlanks(final boolean b) {
    316        this.encodeBlanks = b;
    317    }
    318}