/**
 * Creates a SVG Document instance.
 * This method supports gzipped sources.
 * @param uri The document URI.
 * @exception IOException if an error occured while reading the document.
 */
public Document createDocument(String uri) throws IOException {
    ParsedURL purl = new ParsedURL(uri);

    InputStream is = purl.openStream
       (MimeTypeConstants.MIME_TYPES_SVG_LIST.iterator());
    uri = purl.getPostConnectionURL();

    InputSource isrc = new InputSource(is);

    // now looking for a charset encoding in the content type such
    // as "image/svg+xml; charset=iso8859-1" this is not official
    // for image/svg+xml yet! only for text/xml and maybe
    // for application/xml
    String contentType = purl.getContentType();
    int cindex = -1;
    if (contentType != null) {
        contentType = contentType.toLowerCase();
        cindex = contentType.indexOf(HTTP_CHARSET);
    }

    String charset = null;
    if (cindex != -1) {
        int i                 = cindex + HTTP_CHARSET.length();
        int eqIdx = contentType.indexOf('=', i);
        if (eqIdx != -1) {
            eqIdx++; // no one is interested in the equals sign...

            // The patch had ',' as the terminator but I suspect
            // that is the delimiter between possible charsets,
            // but if another 'attribute' were in the accept header
            // charset would be terminated by a ';'.  So I look
            // for both and take to closer of the two.
            int idx     = contentType.indexOf(',', eqIdx);
            int semiIdx = contentType.indexOf(';', eqIdx);
            if ((semiIdx != -1) && ((semiIdx < idx) || (idx == -1)))
                idx = semiIdx;
            if (idx != -1)
                charset = contentType.substring(eqIdx, idx);
            else
                charset = contentType.substring(eqIdx);
            charset = charset.trim();
            isrc.setEncoding(charset);
        }
    }

    isrc.setSystemId(uri);

    SVGOMDocument doc = (SVGOMDocument) super.createDocument
        (SVGDOMImplementation.SVG_NAMESPACE_URI, "svg", uri, isrc);
    doc.setParsedURL(new ParsedURL(uri));
    doc.setDocumentInputEncoding(charset);
    doc.setXmlStandalone(isStandalone);
    doc.setXmlVersion(xmlVersion);

    return doc;
}

/**
 * Creates a Document.
 * @param is  The document input source.
 * @exception IOException if an error occured while reading the document.
 */
protected Document createDocument(InputSource is)
    throws IOException {
    try {
        if (parserClassName != null) {
            parser = XMLReaderFactory.createXMLReader(parserClassName);
        } else {
            SAXParser saxParser;
            try {
                saxParser = saxFactory.newSAXParser();
            } catch (ParserConfigurationException pce) {
                throw new IOException("Could not create SAXParser: "
                        + pce.getMessage());
            }
            parser = saxParser.getXMLReader();
        }

        parser.setContentHandler(this);
        parser.setDTDHandler(this);
        parser.setEntityResolver(this);
        parser.setErrorHandler((errorHandler == null) ?
                               this : errorHandler);

        parser.setFeature("http://xml.org/sax/features/namespaces",
                          true);
        parser.setFeature("http://xml.org/sax/features/namespace-prefixes",
                          true);
        parser.setFeature("http://xml.org/sax/features/validation",
                          isValidating);
        parser.setProperty("http://xml.org/sax/properties/lexical-handler",
                           this);
        parser.parse(is);
    } catch (SAXException e) {
        Exception ex = e.getException();
        if (ex != null && ex instanceof InterruptedIOException) {
            throw (InterruptedIOException)ex;
        }
        throw new SAXIOException(e);
    }

    currentNode  = null;
    Document ret = document;
    document     = null;
    doctype      = null;
    locator      = null;
    parser       = null;
    return ret;
}