    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 *      http://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 */
    017package org.apache.commons.io.input;
    018
    019import java.io.BufferedInputStream;
    020import java.io.BufferedReader;
    021import java.io.File;
    022import java.io.FileInputStream;
    023import java.io.IOException;
    024import java.io.InputStream;
    025import java.io.InputStreamReader;
    026import java.io.Reader;
    027import java.io.StringReader;
    028import java.net.HttpURLConnection;
    029import java.net.URL;
    030import java.net.URLConnection;
    031import java.text.MessageFormat;
    032import java.util.Locale;
    033import java.util.Objects;
    034import java.util.regex.Matcher;
    035import java.util.regex.Pattern;
    036
    037import org.apache.commons.io.ByteOrderMark;
    038import org.apache.commons.io.IOUtils;
    039
    040/**
    041 * Character stream that handles all the necessary Voodoo to figure out the
    042 * charset encoding of the XML document within the stream.
    043 * <p>
    044 * IMPORTANT: This class is not related in any way to the org.xml.sax.XMLReader.
    045 * This one IS a character stream.
    046 * </p>
    047 * <p>
    048 * All this has to be done without consuming characters from the stream, if not
    049 * the XML parser will not recognized the document as a valid XML. This is not
    050 * 100% true, but it's close enough (UTF-8 BOM is not handled by all parsers
    051 * right now, XmlStreamReader handles it and things work in all parsers).
    052 * </p>
    053 * <p>
    054 * The XmlStreamReader class handles the charset encoding of XML documents in
    055 * Files, raw streams and HTTP streams by offering a wide set of constructors.
    056 * </p>
    057 * <p>
    058 * By default the charset encoding detection is lenient, the constructor with
    059 * the lenient flag can be used for a script (following HTTP MIME and XML
    060 * specifications). All this is nicely explained by Mark Pilgrim in his blog, <a
    061 * href="http://diveintomark.org/archives/2004/02/13/xml-media-types">
    062 * Determining the character encoding of a feed</a>.
    063 * </p>
    064 * <p>
    065 * Originally developed for <a href="http://rome.dev.java.net">ROME</a> under
    066 * Apache License 2.0.
    067 * </p>
    068 *
    069 * @see org.apache.commons.io.output.XmlStreamWriter
    070 * @since 2.0
    071 */
    072public class XmlStreamReader extends Reader {
    073    private static final String UTF_8 = "UTF-8";
    074
    075    private static final String US_ASCII = "US-ASCII";
    076
    077    private static final String UTF_16BE = "UTF-16BE";
    078
    079    private static final String UTF_16LE = "UTF-16LE";
    080
    081    private static final String UTF_32BE = "UTF-32BE";
    082
    083    private static final String UTF_32LE = "UTF-32LE";
    084
    085    private static final String UTF_16 = "UTF-16";
    086
    087    private static final String UTF_32 = "UTF-32";
    088
    089    private static final String EBCDIC = "CP1047";
    090
    091    private static final ByteOrderMark[] BOMS = {
    092        ByteOrderMark.UTF_8,
    093        ByteOrderMark.UTF_16BE,
    094        ByteOrderMark.UTF_16LE,
    095        ByteOrderMark.UTF_32BE,
    096        ByteOrderMark.UTF_32LE
    097    };
    098
    099    // UTF_16LE and UTF_32LE have the same two starting BOM bytes.
    100    private static final ByteOrderMark[] XML_GUESS_BYTES = {
    101        new ByteOrderMark(UTF_8,    0x3C, 0x3F, 0x78, 0x6D),
    102        new ByteOrderMark(UTF_16BE, 0x00, 0x3C, 0x00, 0x3F),
    103        new ByteOrderMark(UTF_16LE, 0x3C, 0x00, 0x3F, 0x00),
    104        new ByteOrderMark(UTF_32BE, 0x00, 0x00, 0x00, 0x3C,
    105                0x00, 0x00, 0x00, 0x3F, 0x00, 0x00, 0x00, 0x78, 0x00, 0x00, 0x00, 0x6D),
    106        new ByteOrderMark(UTF_32LE, 0x3C, 0x00, 0x00, 0x00,
    107                0x3F, 0x00, 0x00, 0x00, 0x78, 0x00, 0x00, 0x00, 0x6D, 0x00, 0x00, 0x00),
    108        new ByteOrderMark(EBCDIC,   0x4C, 0x6F, 0xA7, 0x94)
    109    };
    110
    111    private static final Pattern CHARSET_PATTERN = Pattern
    112            .compile("charset=[\"']?([.[^; \"']]*)[\"']?");
    113
    114    /**
    115     * Pattern capturing the encoding of the "xml" processing instruction.
    116     */
    117    public static final Pattern ENCODING_PATTERN = Pattern.compile(
    118            "<\\?xml.*encoding[\\s]*=[\\s]*((?:\".[^\"]*\")|(?:'.[^']*'))",
    119            Pattern.MULTILINE);
    120
    121    private static final String RAW_EX_1 =
    122        "Invalid encoding, BOM [{0}] XML guess [{1}] XML prolog [{2}] encoding mismatch";
    123
    124    private static final String RAW_EX_2 =
    125        "Invalid encoding, BOM [{0}] XML guess [{1}] XML prolog [{2}] unknown BOM";
    126
    127    private static final String HTTP_EX_1 =
    128        "Invalid encoding, CT-MIME [{0}] CT-Enc [{1}] BOM [{2}] XML guess [{3}] XML prolog [{4}], BOM must be NULL";
    129
    130    private static final String HTTP_EX_2 =
    131        "Invalid encoding, CT-MIME [{0}] CT-Enc [{1}] BOM [{2}] XML guess [{3}] XML prolog [{4}], encoding mismatch";
    132
    133    private static final String HTTP_EX_3 =
    134        "Invalid encoding, CT-MIME [{0}] CT-Enc [{1}] BOM [{2}] XML guess [{3}] XML prolog [{4}], Invalid MIME";
    135
    136    /**
    137     * Returns charset parameter value, NULL if not present, NULL if
    138     * httpContentType is NULL.
    139     *
    140     * @param httpContentType the HTTP content type
    141     * @return The content type encoding (upcased)
    142     */
    143    static String getContentTypeEncoding(final String httpContentType) {
    144        String encoding = null;
    145        if (httpContentType != null) {
    146            final int i = httpContentType.indexOf(";");
    147            if (i > -1) {
    148                final String postMime = httpContentType.substring(i + 1);
    149                final Matcher m = CHARSET_PATTERN.matcher(postMime);
    150                encoding = m.find() ? m.group(1) : null;
    151                encoding = encoding != null ? encoding.toUpperCase(Locale.ROOT) : null;
    152            }
    153        }
    154        return encoding;
    155    }
    156
    157    /**
    158     * Returns MIME type or NULL if httpContentType is NULL.
    159     *
    160     * @param httpContentType the HTTP content type
    161     * @return The mime content type
    162     */
    163    static String getContentTypeMime(final String httpContentType) {
    164        String mime = null;
    165        if (httpContentType != null) {
    166            final int i = httpContentType.indexOf(";");
    167            if (i >= 0) {
    168                mime = httpContentType.substring(0, i);
    169            } else {
    170                mime = httpContentType;
    171            }
    172            mime = mime.trim();
    173        }
    174        return mime;
    175    }
    176
    177    /**
    178     * Returns the encoding declared in the <?xml encoding=...?>, NULL if none.
    179     *
    180     * @param inputStream InputStream to create the reader from.
    181     * @param guessedEnc guessed encoding
    182     * @return the encoding declared in the <?xml encoding=...?>
    183     * @throws IOException thrown if there is a problem reading the stream.
    184     */
    185    private static String getXmlProlog(final InputStream inputStream, final String guessedEnc)
    186            throws IOException {
    187        String encoding = null;
    188        if (guessedEnc != null) {
    189            final byte[] bytes = IOUtils.byteArray();
    190            inputStream.mark(IOUtils.DEFAULT_BUFFER_SIZE);
    191            int offset = 0;
    192            int max = IOUtils.DEFAULT_BUFFER_SIZE;
    193            int c = inputStream.read(bytes, offset, max);
    194            int firstGT = -1;
    195            String xmlProlog = ""; // avoid possible NPE warning (cannot happen; this just silences the warning)
    196            while (c != -1 && firstGT == -1 && offset < IOUtils.DEFAULT_BUFFER_SIZE) {
    197                offset += c;
    198                max -= c;
    199                c = inputStream.read(bytes, offset, max);
    200                xmlProlog = new String(bytes, 0, offset, guessedEnc);
    201                firstGT = xmlProlog.indexOf('>');
    202            }
    203            if (firstGT == -1) {
    204                if (c == -1) {
    205                    throw new IOException("Unexpected end of XML stream");
    206                }
    207                throw new IOException(
    208                        "XML prolog or ROOT element not found on first "
    209                                + offset + " bytes");
    210            }
    211            final int bytesRead = offset;
    212            if (bytesRead > 0) {
    213                inputStream.reset();
    214                final BufferedReader bReader = new BufferedReader(new StringReader(
    215                        xmlProlog.substring(0, firstGT + 1)));
    216                final StringBuffer prolog = new StringBuffer();
    217                String line;
    218                while ((line = bReader.readLine()) != null) {
    219                    prolog.append(line);
    220                }
    221                final Matcher m = ENCODING_PATTERN.matcher(prolog);
    222                if (m.find()) {
    223                    encoding = m.group(1).toUpperCase(Locale.ROOT);
    224                    encoding = encoding.substring(1, encoding.length() - 1);
    225                }
    226            }
    227        }
    228        return encoding;
    229    }
    230
    231    /**
    232     * Indicates if the MIME type belongs to the APPLICATION XML family.
    233     *
    234     * @param mime The mime type
    235     * @return true if the mime type belongs to the APPLICATION XML family,
    236     * otherwise false
    237     */
    238    static boolean isAppXml(final String mime) {
    239        return mime != null &&
    240               (mime.equals("application/xml") ||
    241                mime.equals("application/xml-dtd") ||
    242                mime.equals("application/xml-external-parsed-entity") ||
    243               mime.startsWith("application/") && mime.endsWith("+xml"));
    244    }
    245
    246    /**
    247     * Indicates if the MIME type belongs to the TEXT XML family.
    248     *
    249     * @param mime The mime type
    250     * @return true if the mime type belongs to the TEXT XML family,
    251     * otherwise false
    252     */
    253    static boolean isTextXml(final String mime) {
    254        return mime != null &&
    255              (mime.equals("text/xml") ||
    256               mime.equals("text/xml-external-parsed-entity") ||
    257              mime.startsWith("text/") && mime.endsWith("+xml"));
    258    }
    259
    260    private final Reader reader;
    261
    262    private final String encoding;
    263
    264    private final String defaultEncoding;
    265
    266    /**
    267     * Creates a Reader for a File.
    268     * <p>
    269     * It looks for the UTF-8 BOM first, if none sniffs the XML prolog charset,
    270     * if this is also missing defaults to UTF-8.
    271     * <p>
    272     * It does a lenient charset encoding detection, check the constructor with
    273     * the lenient parameter for details.
    274     *
    275     * @param file File to create a Reader from.
    276     * @throws IOException thrown if there is a problem reading the file.
    277     */
    278    @SuppressWarnings("resource") // FileInputStream is managed through another reader in this instance.
    279    public XmlStreamReader(final File file) throws IOException {
    280        this(new FileInputStream(Objects.requireNonNull(file, "file")));
    281    }
    282
    283    /**
    284     * Creates a Reader for a raw InputStream.
    285     * <p>
    286     * It follows the same logic used for files.
    287     * <p>
    288     * It does a lenient charset encoding detection, check the constructor with
    289     * the lenient parameter for details.
    290     *
    291     * @param inputStream InputStream to create a Reader from.
    292     * @throws IOException thrown if there is a problem reading the stream.
    293     */
    294    public XmlStreamReader(final InputStream inputStream) throws IOException {
    295        this(inputStream, true);
    296    }
    297
    298    /**
    299     * Creates a Reader for a raw InputStream.
    300     * <p>
    301     * It follows the same logic used for files.
    302     * <p>
    303     * If lenient detection is indicated and the detection above fails as per
    304     * specifications it then attempts the following:
    305     * <p>
    306     * If the content type was 'text/html' it replaces it with 'text/xml' and
    307     * tries the detection again.
    308     * <p>
    309     * Else if the XML prolog had a charset encoding that encoding is used.
    310     * <p>
    311     * Else if the content type had a charset encoding that encoding is used.
    312     * <p>
    313     * Else 'UTF-8' is used.
    314     * <p>
    315     * If lenient detection is indicated an XmlStreamReaderException is never
    316     * thrown.
    317     *
    318     * @param inputStream InputStream to create a Reader from.
    319     * @param lenient indicates if the charset encoding detection should be
    320     *        relaxed.
    321     * @throws IOException thrown if there is a problem reading the stream.
    322     * @throws XmlStreamReaderException thrown if the charset encoding could not
    323     *         be determined according to the specs.
    324     */
    325    public XmlStreamReader(final InputStream inputStream, final boolean lenient) throws IOException {
    326        this(inputStream, lenient, null);
    327    }
    328
    329    /**
    330     * Creates a Reader for a raw InputStream.
    331     * <p>
    332     * It follows the same logic used for files.
    333     * <p>
    334     * If lenient detection is indicated and the detection above fails as per
    335     * specifications it then attempts the following:
    336     * <p>
    337     * If the content type was 'text/html' it replaces it with 'text/xml' and
    338     * tries the detection again.
    339     * <p>
    340     * Else if the XML prolog had a charset encoding that encoding is used.
    341     * <p>
    342     * Else if the content type had a charset encoding that encoding is used.
    343     * <p>
    344     * Else 'UTF-8' is used.
    345     * <p>
    346     * If lenient detection is indicated an XmlStreamReaderException is never
    347     * thrown.
    348     *
    349     * @param inputStream InputStream to create a Reader from.
    350     * @param lenient indicates if the charset encoding detection should be
    351     *        relaxed.
    352     * @param defaultEncoding The default encoding
    353     * @throws IOException thrown if there is a problem reading the stream.
    354     * @throws XmlStreamReaderException thrown if the charset encoding could not
    355     *         be determined according to the specs.
    356     */
    357    @SuppressWarnings("resource") // InputStream is managed through a InputStreamReader in this instance.
    358    public XmlStreamReader(final InputStream inputStream, final boolean lenient, final String defaultEncoding)
    359            throws IOException {
    360        Objects.requireNonNull(inputStream, "inputStream");
    361        this.defaultEncoding = defaultEncoding;
    362        final BOMInputStream bom = new BOMInputStream(new BufferedInputStream(inputStream, IOUtils.DEFAULT_BUFFER_SIZE), false, BOMS);
    363        final BOMInputStream pis = new BOMInputStream(bom, true, XML_GUESS_BYTES);
    364        this.encoding = doRawStream(bom, pis, lenient);
    365        this.reader = new InputStreamReader(pis, encoding);
    366    }
    367
    368    /**
    369     * Creates a Reader using an InputStream and the associated content-type
    370     * header.
    371     * <p>
    372     * First it checks if the stream has BOM. If there is not BOM checks the
    373     * content-type encoding. If there is not content-type encoding checks the
    374     * XML prolog encoding. If there is not XML prolog encoding uses the default
    375     * encoding mandated by the content-type MIME type.
    376     * <p>
    377     * It does a lenient charset encoding detection, check the constructor with
    378     * the lenient parameter for details.
    379     *
    380     * @param inputStream InputStream to create the reader from.
    381     * @param httpContentType content-type header to use for the resolution of
    382     *        the charset encoding.
    383     * @throws IOException thrown if there is a problem reading the file.
    384     */
    385    public XmlStreamReader(final InputStream inputStream, final String httpContentType)
    386            throws IOException {
    387        this(inputStream, httpContentType, true);
    388    }
    389
    390
    391    /**
    392     * Creates a Reader using an InputStream and the associated content-type
    393     * header. This constructor is lenient regarding the encoding detection.
    394     * <p>
    395     * First it checks if the stream has BOM. If there is not BOM checks the
    396     * content-type encoding. If there is not content-type encoding checks the
    397     * XML prolog encoding. If there is not XML prolog encoding uses the default
    398     * encoding mandated by the content-type MIME type.
    399     * <p>
    400     * If lenient detection is indicated and the detection above fails as per
    401     * specifications it then attempts the following:
    402     * <p>
    403     * If the content type was 'text/html' it replaces it with 'text/xml' and
    404     * tries the detection again.
    405     * <p>
    406     * Else if the XML prolog had a charset encoding that encoding is used.
    407     * <p>
    408     * Else if the content type had a charset encoding that encoding is used.
    409     * <p>
    410     * Else 'UTF-8' is used.
    411     * <p>
    412     * If lenient detection is indicated an XmlStreamReaderException is never
    413     * thrown.
    414     *
    415     * @param inputStream InputStream to create the reader from.
    416     * @param httpContentType content-type header to use for the resolution of
    417     *        the charset encoding.
    418     * @param lenient indicates if the charset encoding detection should be
    419     *        relaxed.
    420     * @throws IOException thrown if there is a problem reading the file.
    421     * @throws XmlStreamReaderException thrown if the charset encoding could not
    422     *         be determined according to the specs.
    423     */
    424    public XmlStreamReader(final InputStream inputStream, final String httpContentType,
    425            final boolean lenient) throws IOException {
    426        this(inputStream, httpContentType, lenient, null);
    427    }
    428
    429    /**
    430     * Creates a Reader using an InputStream and the associated content-type
    431     * header. This constructor is lenient regarding the encoding detection.
    432     * <p>
    433     * First it checks if the stream has BOM. If there is not BOM checks the
    434     * content-type encoding. If there is not content-type encoding checks the
    435     * XML prolog encoding. If there is not XML prolog encoding uses the default
    436     * encoding mandated by the content-type MIME type.
    437     * <p>
    438     * If lenient detection is indicated and the detection above fails as per
    439     * specifications it then attempts the following:
    440     * <p>
    441     * If the content type was 'text/html' it replaces it with 'text/xml' and
    442     * tries the detection again.
    443     * <p>
    444     * Else if the XML prolog had a charset encoding that encoding is used.
    445     * <p>
    446     * Else if the content type had a charset encoding that encoding is used.
    447     * <p>
    448     * Else 'UTF-8' is used.
    449     * <p>
    450     * If lenient detection is indicated an XmlStreamReaderException is never
    451     * thrown.
    452     *
    453     * @param inputStream InputStream to create the reader from.
    454     * @param httpContentType content-type header to use for the resolution of
    455     *        the charset encoding.
    456     * @param lenient indicates if the charset encoding detection should be
    457     *        relaxed.
    458     * @param defaultEncoding The default encoding
    459     * @throws IOException thrown if there is a problem reading the file.
    460     * @throws XmlStreamReaderException thrown if the charset encoding could not
    461     *         be determined according to the specs.
    462     */
    463    @SuppressWarnings("resource") // InputStream is managed through a InputStreamReader in this instance.
    464    public XmlStreamReader(final InputStream inputStream, final String httpContentType,
    465            final boolean lenient, final String defaultEncoding) throws IOException {
    466        Objects.requireNonNull(inputStream, "inputStream");
    467        this.defaultEncoding = defaultEncoding;
    468        final BOMInputStream bom = new BOMInputStream(new BufferedInputStream(inputStream, IOUtils.DEFAULT_BUFFER_SIZE), false, BOMS);
    469        final BOMInputStream pis = new BOMInputStream(bom, true, XML_GUESS_BYTES);
    470        this.encoding = processHttpStream(bom, pis, httpContentType, lenient);
    471        this.reader = new InputStreamReader(pis, encoding);
    472    }
    473
    474    /**
    475     * Creates a Reader using the InputStream of a URL.
    476     * <p>
    477     * If the URL is not of type HTTP and there is not 'content-type' header in
    478     * the fetched data it uses the same logic used for Files.
    479     * <p>
    480     * If the URL is a HTTP Url or there is a 'content-type' header in the
    481     * fetched data it uses the same logic used for an InputStream with
    482     * content-type.
    483     * <p>
    484     * It does a lenient charset encoding detection, check the constructor with
    485     * the lenient parameter for details.
    486     *
    487     * @param url URL to create a Reader from.
    488     * @throws IOException thrown if there is a problem reading the stream of
    489     *         the URL.
    490     */
    491    public XmlStreamReader(final URL url) throws IOException {
    492        this(Objects.requireNonNull(url, "url").openConnection(), null);
    493    }
    494
    495    /**
    496     * Creates a Reader using the InputStream of a URLConnection.
    497     * <p>
    498     * If the URLConnection is not of type HttpURLConnection and there is not
    499     * 'content-type' header in the fetched data it uses the same logic used for
    500     * files.
    501     * <p>
    502     * If the URLConnection is a HTTP Url or there is a 'content-type' header in
    503     * the fetched data it uses the same logic used for an InputStream with
    504     * content-type.
    505     * <p>
    506     * It does a lenient charset encoding detection, check the constructor with
    507     * the lenient parameter for details.
    508     *
    509     * @param conn URLConnection to create a Reader from.
    510     * @param defaultEncoding The default encoding
    511     * @throws IOException thrown if there is a problem reading the stream of
    512     *         the URLConnection.
    513     */
    514    public XmlStreamReader(final URLConnection conn, final String defaultEncoding) throws IOException {
    515        Objects.requireNonNull(conn, "conn");
    516        this.defaultEncoding = defaultEncoding;
    517        final boolean lenient = true;
    518        final String contentType = conn.getContentType();
    519        final InputStream inputStream = conn.getInputStream();
    520        @SuppressWarnings("resource") // managed by the InputStreamReader tracked by this instance
    521        final BOMInputStream bom = new BOMInputStream(new BufferedInputStream(inputStream, IOUtils.DEFAULT_BUFFER_SIZE), false, BOMS);
    522        final BOMInputStream pis = new BOMInputStream(bom, true, XML_GUESS_BYTES);
    523        if (conn instanceof HttpURLConnection || contentType != null) {
    524            this.encoding = processHttpStream(bom, pis, contentType, lenient);
    525        } else {
    526            this.encoding = doRawStream(bom, pis, lenient);
    527        }
    528        this.reader = new InputStreamReader(pis, encoding);
    529    }
    530
    531    /**
    532     * Calculate the HTTP encoding.
    533     *
    534     * @param httpContentType The HTTP content type
    535     * @param bomEnc BOM encoding
    536     * @param xmlGuessEnc XML Guess encoding
    537     * @param xmlEnc XML encoding
    538     * @param lenient indicates if the charset encoding detection should be
    539     *        relaxed.
    540     * @return the HTTP encoding
    541     * @throws IOException thrown if there is a problem reading the stream.
    542     */
    543    String calculateHttpEncoding(final String httpContentType,
    544            final String bomEnc, final String xmlGuessEnc, final String xmlEnc,
    545            final boolean lenient) throws IOException {
    546
    547        // Lenient and has XML encoding
    548        if (lenient && xmlEnc != null) {
    549            return xmlEnc;
    550        }
    551
    552        // Determine mime/encoding content types from HTTP Content Type
    553        final String cTMime = getContentTypeMime(httpContentType);
    554        final String cTEnc  = getContentTypeEncoding(httpContentType);
    555        final boolean appXml  = isAppXml(cTMime);
    556        final boolean textXml = isTextXml(cTMime);
    557
    558        // Mime type NOT "application/xml" or "text/xml"
    559        if (!appXml && !textXml) {
    560            final String msg = MessageFormat.format(HTTP_EX_3, cTMime, cTEnc, bomEnc, xmlGuessEnc, xmlEnc);
    561            throw new XmlStreamReaderException(msg, cTMime, cTEnc, bomEnc, xmlGuessEnc, xmlEnc);
    562        }
    563
    564        // No content type encoding
    565        if (cTEnc == null) {
    566            if (appXml) {
    567                return calculateRawEncoding(bomEnc, xmlGuessEnc, xmlEnc);
    568            }
    569            return defaultEncoding == null ? US_ASCII : defaultEncoding;
    570        }
    571
    572        // UTF-16BE or UTF-16LE content type encoding
    573        if (cTEnc.equals(UTF_16BE) || cTEnc.equals(UTF_16LE)) {
    574            if (bomEnc != null) {
    575                final String msg = MessageFormat.format(HTTP_EX_1, cTMime, cTEnc, bomEnc, xmlGuessEnc, xmlEnc);
    576                throw new XmlStreamReaderException(msg, cTMime, cTEnc, bomEnc, xmlGuessEnc, xmlEnc);
    577            }
    578            return cTEnc;
    579        }
    580
    581        // UTF-16 content type encoding
    582        if (cTEnc.equals(UTF_16)) {
    583            if (bomEnc != null && bomEnc.startsWith(UTF_16)) {
    584                return bomEnc;
    585            }
    586            final String msg = MessageFormat.format(HTTP_EX_2, cTMime, cTEnc, bomEnc, xmlGuessEnc, xmlEnc);
    587            throw new XmlStreamReaderException(msg, cTMime, cTEnc, bomEnc, xmlGuessEnc, xmlEnc);
    588        }
    589
    590        // UTF-32BE or UTF-132E content type encoding
    591        if (cTEnc.equals(UTF_32BE) || cTEnc.equals(UTF_32LE)) {
    592            if (bomEnc != null) {
    593                final String msg = MessageFormat.format(HTTP_EX_1, cTMime, cTEnc, bomEnc, xmlGuessEnc, xmlEnc);
    594                throw new XmlStreamReaderException(msg, cTMime, cTEnc, bomEnc, xmlGuessEnc, xmlEnc);
    595            }
    596            return cTEnc;
    597        }
    598
    599        // UTF-32 content type encoding
    600        if (cTEnc.equals(UTF_32)) {
    601            if (bomEnc != null && bomEnc.startsWith(UTF_32)) {
    602                return bomEnc;
    603            }
    604            final String msg = MessageFormat.format(HTTP_EX_2, cTMime, cTEnc, bomEnc, xmlGuessEnc, xmlEnc);
    605            throw new XmlStreamReaderException(msg, cTMime, cTEnc, bomEnc, xmlGuessEnc, xmlEnc);
    606        }
    607
    608        return cTEnc;
    609    }
    610
    611    /**
    612     * Calculate the raw encoding.
    613     *
    614     * @param bomEnc BOM encoding
    615     * @param xmlGuessEnc XML Guess encoding
    616     * @param xmlEnc XML encoding
    617     * @return the raw encoding
    618     * @throws IOException thrown if there is a problem reading the stream.
    619     */
    620    String calculateRawEncoding(final String bomEnc, final String xmlGuessEnc,
    621            final String xmlEnc) throws IOException {
    622
    623        // BOM is Null
    624        if (bomEnc == null) {
    625            if (xmlGuessEnc == null || xmlEnc == null) {
    626                return defaultEncoding == null ? UTF_8 : defaultEncoding;
    627            }
    628            if (xmlEnc.equals(UTF_16) &&
    629               (xmlGuessEnc.equals(UTF_16BE) || xmlGuessEnc.equals(UTF_16LE))) {
    630                return xmlGuessEnc;
    631            }
    632            return xmlEnc;
    633        }
    634
    635        // BOM is UTF-8
    636        if (bomEnc.equals(UTF_8)) {
    637            if (xmlGuessEnc != null && !xmlGuessEnc.equals(UTF_8)) {
    638                final String msg = MessageFormat.format(RAW_EX_1, bomEnc, xmlGuessEnc, xmlEnc);
    639                throw new XmlStreamReaderException(msg, bomEnc, xmlGuessEnc, xmlEnc);
    640            }
    641            if (xmlEnc != null && !xmlEnc.equals(UTF_8)) {
    642                final String msg = MessageFormat.format(RAW_EX_1, bomEnc, xmlGuessEnc, xmlEnc);
    643                throw new XmlStreamReaderException(msg, bomEnc, xmlGuessEnc, xmlEnc);
    644            }
    645            return bomEnc;
    646        }
    647
    648        // BOM is UTF-16BE or UTF-16LE
    649        if (bomEnc.equals(UTF_16BE) || bomEnc.equals(UTF_16LE)) {
    650            if (xmlGuessEnc != null && !xmlGuessEnc.equals(bomEnc)) {
    651                final String msg = MessageFormat.format(RAW_EX_1, bomEnc, xmlGuessEnc, xmlEnc);
    652                throw new XmlStreamReaderException(msg, bomEnc, xmlGuessEnc, xmlEnc);
    653            }
    654            if (xmlEnc != null && !xmlEnc.equals(UTF_16) && !xmlEnc.equals(bomEnc)) {
    655                final String msg = MessageFormat.format(RAW_EX_1, bomEnc, xmlGuessEnc, xmlEnc);
    656                throw new XmlStreamReaderException(msg, bomEnc, xmlGuessEnc, xmlEnc);
    657            }
    658            return bomEnc;
    659        }
    660
    661        // BOM is UTF-32BE or UTF-32LE
    662        if (bomEnc.equals(UTF_32BE) || bomEnc.equals(UTF_32LE)) {
    663            if (xmlGuessEnc != null && !xmlGuessEnc.equals(bomEnc)) {
    664                final String msg = MessageFormat.format(RAW_EX_1, bomEnc, xmlGuessEnc, xmlEnc);
    665                throw new XmlStreamReaderException(msg, bomEnc, xmlGuessEnc, xmlEnc);
    666            }
    667            if (xmlEnc != null && !xmlEnc.equals(UTF_32) && !xmlEnc.equals(bomEnc)) {
    668                final String msg = MessageFormat.format(RAW_EX_1, bomEnc, xmlGuessEnc, xmlEnc);
    669                throw new XmlStreamReaderException(msg, bomEnc, xmlGuessEnc, xmlEnc);
    670            }
    671            return bomEnc;
    672        }
    673
    674        // BOM is something else
    675        final String msg = MessageFormat.format(RAW_EX_2, bomEnc, xmlGuessEnc, xmlEnc);
    676        throw new XmlStreamReaderException(msg, bomEnc, xmlGuessEnc, xmlEnc);
    677    }
    678
    679    /**
    680     * Closes the XmlStreamReader stream.
    681     *
    682     * @throws IOException thrown if there was a problem closing the stream.
    683     */
    684    @Override
    685    public void close() throws IOException {
    686        reader.close();
    687    }
    688
    689    /**
    690     * Do lenient detection.
    691     *
    692     * @param httpContentType content-type header to use for the resolution of
    693     *        the charset encoding.
    694     * @param ex The thrown exception
    695     * @return the encoding
    696     * @throws IOException thrown if there is a problem reading the stream.
    697     */
    698    private String doLenientDetection(String httpContentType,
    699            XmlStreamReaderException ex) throws IOException {
    700        if (httpContentType != null && httpContentType.startsWith("text/html")) {
    701            httpContentType = httpContentType.substring("text/html".length());
    702            httpContentType = "text/xml" + httpContentType;
    703            try {
    704                return calculateHttpEncoding(httpContentType, ex.getBomEncoding(),
    705                        ex.getXmlGuessEncoding(), ex.getXmlEncoding(), true);
    706            } catch (final XmlStreamReaderException ex2) {
    707                ex = ex2;
    708            }
    709        }
    710        String encoding = ex.getXmlEncoding();
    711        if (encoding == null) {
    712            encoding = ex.getContentTypeEncoding();
    713        }
    714        if (encoding == null) {
    715            encoding = defaultEncoding == null ? UTF_8 : defaultEncoding;
    716        }
    717        return encoding;
    718    }
    719
    720    /**
    721     * Process the raw stream.
    722     *
    723     * @param bom BOMInputStream to detect byte order marks
    724     * @param pis BOMInputStream to guess XML encoding
    725     * @param lenient indicates if the charset encoding detection should be
    726     *        relaxed.
    727     * @return the encoding to be used
    728     * @throws IOException thrown if there is a problem reading the stream.
    729     */
    730    private String doRawStream(final BOMInputStream bom, final BOMInputStream pis, final boolean lenient)
    731            throws IOException {
    732        final String bomEnc      = bom.getBOMCharsetName();
    733        final String xmlGuessEnc = pis.getBOMCharsetName();
    734        final String xmlEnc = getXmlProlog(pis, xmlGuessEnc);
    735        try {
    736            return calculateRawEncoding(bomEnc, xmlGuessEnc, xmlEnc);
    737        } catch (final XmlStreamReaderException ex) {
    738            if (lenient) {
    739                return doLenientDetection(null, ex);
    740            }
    741            throw ex;
    742        }
    743    }
    744
    745    /**
    746     * Returns the default encoding to use if none is set in HTTP content-type,
    747     * XML prolog and the rules based on content-type are not adequate.
    748     * <p>
    749     * If it is NULL the content-type based rules are used.
    750     *
    751     * @return the default encoding to use.
    752     */
    753    public String getDefaultEncoding() {
    754        return defaultEncoding;
    755    }
    756
    757    /**
    758     * Returns the charset encoding of the XmlStreamReader.
    759     *
    760     * @return charset encoding.
    761     */
    762    public String getEncoding() {
    763        return encoding;
    764    }
    765
    766    /**
    767     * Process a HTTP stream.
    768     *
    769     * @param bom BOMInputStream to detect byte order marks
    770     * @param pis BOMInputStream to guess XML encoding
    771     * @param httpContentType The HTTP content type
    772     * @param lenient indicates if the charset encoding detection should be
    773     *        relaxed.
    774     * @return the encoding to be used
    775     * @throws IOException thrown if there is a problem reading the stream.
    776     */
    777    private String processHttpStream(final BOMInputStream bom, final BOMInputStream pis, final String httpContentType,
    778        final boolean lenient) throws IOException {
    779        final String bomEnc = bom.getBOMCharsetName();
    780        final String xmlGuessEnc = pis.getBOMCharsetName();
    781        final String xmlEnc = getXmlProlog(pis, xmlGuessEnc);
    782        try {
    783            return calculateHttpEncoding(httpContentType, bomEnc, xmlGuessEnc, xmlEnc, lenient);
    784        } catch (final XmlStreamReaderException ex) {
    785            if (lenient) {
    786                return doLenientDetection(httpContentType, ex);
    787            }
    788            throw ex;
    789        }
    790    }
    791
    792    /**
    793     * Invokes the underlying reader's {@code read(char[], int, int)} method.
    794     * @param buf the buffer to read the characters into
    795     * @param offset The start offset
    796     * @param len The number of bytes to read
    797     * @return the number of characters read or -1 if the end of stream
    798     * @throws IOException if an I/O error occurs.
    799     */
    800    @Override
    801    public int read(final char[] buf, final int offset, final int len) throws IOException {
    802        return reader.read(buf, offset, len);
    803    }
    804
    805}