* according to the XML 1.0 specification. Valid characters include:
     * - Tab (0x9)
     * - Line feed (0xA)
     * - Carriage return (0xD)
     * - Any character between 0x20 and 0xD7FF
     * - Any character between 0xE000 and 0xFFFD
     * - Any character between 0x10000 and 0x10FFFF
     *
     * @param in the input string to be processed

         <match value="0x00" type="string" mask="0xF8" offset="5"/>
         <match value="0x08" type="string" mask="0xF8" offset="5"/>
         <match value="0x10" type="string" mask="0xF8" offset="5"/>
         <match value="0x18" type="string" mask="0xF8" offset="5"/>
         <match value="0x20" type="string" mask="0xF8" offset="5"/>
         <match value="0x28" type="string" mask="0xF8" offset="5"/>

    /**
     * UTF-7 Byte Order Mark definition.
     */
    protected static final ByteOrderMark BOM_UTF_7 = new ByteOrderMark("UTF-7", 0x2B, 0x2F, 0x76);

    /**
     * HTML4 unescape translator.
     */
    protected static final CharSequenceTranslator UNESCAPE_HTML4 = new AggregateTranslator(