void write_xml_text(std::basic_ostream<Ch> &stream,
                     const std::basic_string<Ch> &s, 
                     int indent, 
                     bool separate_line)
 {
     typedef typename std::basic_string<Ch> Str;
     if (separate_line)    
         stream << Str(4 * indent, Ch(' '));
     stream << encode_char_entities(s);
     if (separate_line)    
         stream << Ch('\n');
 }
 void write_xml_text(std::basic_ostream<Ch> &stream,
                     const std::basic_string<Ch> &s, 
                     int indent, 
                     bool separate_line,
                     const xml_writer_settings<Ch> & settings
                     )
 {
     if (separate_line)    
         write_xml_indent(stream,indent,settings);
     stream << encode_char_entities(s);
     if (separate_line)
         stream << Ch('\n');
 }
	void write_xml_text(std::basic_ostream<typename Str::value_type> &stream,
                        const Str &s,
                        int indent,
                        bool separate_line,
                        const xml_writer_settings<Str> & settings
                        )
    {
        if (separate_line)
            write_xml_indent(stream,indent,settings);
        stream << encode_char_entities(s);
        if (separate_line)
            stream << typename Str::value_type('\n');
    }
    void write_xml_element(std::basic_ostream<typename Ptree::key_type::value_type> &stream, 
                           const std::basic_string<typename Ptree::key_type::value_type> &key,
                           const Ptree &pt, 
                           int indent,
                           const xml_writer_settings<typename Ptree::key_type::value_type> & settings)
    {

        typedef typename Ptree::key_type::value_type Ch;
        typedef typename Ptree::const_iterator It;

        bool want_pretty = settings.indent_count > 0;
        // Find if elements present
        bool has_elements = false;
        bool has_attrs_only = pt.data().empty();
        for (It it = pt.begin(), end = pt.end(); it != end; ++it)
        {
            if (it->first != xmlattr<Ch>() )
            {
                has_attrs_only = false;
                if (it->first != xmltext<Ch>())
                {
                    has_elements = true;
                    break;
                }
            }
        }
        
        // Write element
        if (pt.data().empty() && pt.empty())    // Empty key
        {
            if (indent >= 0)
            {
                write_xml_indent(stream,indent,settings);
                stream << Ch('<') << key << 
                          Ch('/') << Ch('>');
                if (want_pretty)
                    stream << Ch('\n');
            }
        }
        else    // Nonempty key
        {
        
            // Write opening tag, attributes and data
            if (indent >= 0)
            {
            
                // Write opening brace and key
                write_xml_indent(stream,indent,settings);
                stream << Ch('<') << key;

                // Write attributes
                if (optional<const Ptree &> attribs = pt.get_child_optional(xmlattr<Ch>()))
                    for (It it = attribs.get().begin(); it != attribs.get().end(); ++it)
                        stream << Ch(' ') << it->first << Ch('=')
                               << Ch('"')
                               << encode_char_entities(
                                    it->second.template get_value<std::basic_string<Ch> >())
                               << Ch('"');

                if ( has_attrs_only )
                {
                    // Write closing brace
                    stream << Ch('/') << Ch('>');
                    if (want_pretty)
                        stream << Ch('\n');
                }
                else
                {
                    // Write closing brace
                    stream << Ch('>');

                    // Break line if needed and if we want pretty-printing
                    if (has_elements && want_pretty)
                        stream << Ch('\n');
                }
            }

            // Write data text, if present
            if (!pt.data().empty())
                write_xml_text(stream,
                    pt.template get_value<std::basic_string<Ch> >(),
                    indent + 1, has_elements && want_pretty, settings);

            // Write elements, comments and texts
            for (It it = pt.begin(); it != pt.end(); ++it)
            {
                if (it->first == xmlattr<Ch>())
                    continue;
                else if (it->first == xmlcomment<Ch>())
                    write_xml_comment(stream,
                        it->second.template get_value<std::basic_string<Ch> >(),
                        indent + 1, want_pretty, settings);
                else if (it->first == xmltext<Ch>())
                    write_xml_text(stream,
                        it->second.template get_value<std::basic_string<Ch> >(),
                        indent + 1, has_elements && want_pretty, settings);
                else
                    write_xml_element(stream, it->first, it->second,
                        indent + 1, settings);
            }
            
            // Write closing tag
            if (indent >= 0 && !has_attrs_only)
            {
                if (has_elements)
                    write_xml_indent(stream,indent,settings);
                stream << Ch('<') << Ch('/') << key << Ch('>');
                if (want_pretty)
                    stream << Ch('\n');
            }

        }
    }