xmlwriter.h

//
// xmlwriter.h: interface & implementation for the XmlStream class.
// 
// Author: Oboltus, December 2003
// see: http://www.codeproject.com/vcpp/stl/simple_xmlwriter.asp
//
// This code is provided "as is", with absolutely no warranty expressed
// or implied. Any use is at your own risk.
//
// some code added by Bernd Speiser, 2005-2007 (see BS below)
//

#ifndef __XMLWRITER_H_2CC1D410_9DE8_4452_B8F0_F987EF152E06
#define __XMLWRITER_H_2CC1D410_9DE8_4452_B8F0_F987EF152E06

// disable terrible MSVC warnings which are issued when using STL
#ifdef  _MSC_VER
#pragma warning( disable : 4786 ) 
#pragma warning( disable : 4514 )
#endif

#include        <stack>
#include        <string>
#include        <sstream>
// added by BS to allow use of ofstream
#include        <fstream>

namespace BSUtilities {
namespace xmlw {

class XmlStream {
public:

        // XML version constants
        enum {versionMajor = 1, versionMinor = 0};

        // Internal helper class
        struct Controller {
                typedef enum {whatProlog, whatTag, whatTagEnd, whatAttribute, whatCharData}     what_type;

                what_type       what;
                std::string str;

                inline Controller(const Controller& c) : what(c.what), str(c.str) {}
                inline Controller(const what_type _what) : what(_what){}
                
                // use template constructor because string field <str> may be initialized 
                // from different sources: char*, std::string etc
                template<class t>
                inline Controller(const what_type _what, const t& _str) : what(_what), str(_str) {}
        };

        // XmlStream refers std::ostream object to perform actual output operations
        inline XmlStream(std::ostream&  _s) : s(_s), state(stateNone), prologWritten(false) {}

        // Before destroying check whether all the open tags are closed
        ~XmlStream() {
                if (stateTagName == state) {
                        s << "/>";
                        state = stateNone;
                }
                while (tags.size())
                        endTag(tags.top());
        }

        // default behaviour - delegate object output to std::stream
        template<class t>
        XmlStream& operator<<(const t& value) {
                if (stateTagName == state)
                        tagName << value;
                s << value;
                return *this;
        }

        // this is the main working horse
        // and it's long a little
        XmlStream& operator<<(const Controller& controller) {

                switch (controller.what) {
                case Controller::whatProlog:
                        if (!prologWritten && stateNone == state) {
                                s << "<?xml version=\"" << versionMajor << '.' << versionMinor << "\"?>\n";
                                prologWritten = true;
                        }
                        break;  //      Controller::whatProlog

                case Controller::whatTag:
                        closeTagStart();
                        s << '<';
                        if (controller.str.empty()) {
                                clearTagName();
                                state = stateTagName;
                        }
                        else {
                                s << controller.str;
                                tags.push(controller.str);
                                state = stateTag;
                        }
                        break;  //      Controller::whatTag

                case Controller::whatTagEnd:
                        endTag(controller.str);
                        break;  //      Controller::whatTagEnd

                case Controller::whatAttribute:
                        switch (state) {
                        case stateTagName:
                                tags.push(tagName.str());
                                break;

                        case stateAttribute:
                                s << '\"';
// added default switch, BS
                        default:
                          ;
                        }

                        if (stateNone != state) {
                                s << ' ' << controller.str << "=\"";
                                state = stateAttribute;
                        }
                        // else throw some error - unexpected attribute (out of any tag)

                        break;  //      Controller::whatAttribute

                case Controller::whatCharData:
                        closeTagStart();
                        state = stateNone;
                        break;  //      Controller::whatCharData
                }

                return  *this;
        }

private:
        // state of the stream 
        typedef enum {stateNone, stateTag, stateAttribute, stateTagName}        state_type;

        // tag name stack
        typedef std::stack<std::string> tag_stack_type;

        tag_stack_type  tags;
// exchanged the two following lines, BS
// to avoid warning from gcc about initialization order
        std::ostream&   s;
        state_type      state;
        bool    prologWritten;
        std::ostringstream      tagName;

        // I don't know any way easier (legal) to clear std::stringstream...
        inline void clearTagName() {
                const std::string       empty_str;
                tagName.rdbuf()->str(empty_str);
        }

        // Close current tag
        void closeTagStart(bool self_closed = false) {
                if (stateTagName == state)
                        tags.push(tagName.str());

                // note: absence of 'break's is not an error
                switch (state) {
                case stateAttribute:
                        s << '\"';

                case stateTagName:
                case stateTag:
                        if (self_closed)
                                s << '/';
// added newline, BS
                        s << ">\n";
// added default switch, BS
                default:
                     ;
                }
        }

        // Close tag (may be with closing all of its children)
        void endTag(const std::string& tag) {
                bool    brk = false;

                while (tags.size() > 0 && !brk) {
                        if (stateNone == state)
// added newline, BS
                                s << "</" << tags.top() << ">\n";
                        else {
                                closeTagStart(true);
                                state = stateNone;
                        }
                        brk = tag.empty() || tag == tags.top();
                        tags.pop();
                }
        }
};      //      class XmlStream

// Helper functions, they may be simply overwritten
// E.g. you may use std::string instead of const char*

inline const XmlStream::Controller prolog() {
return XmlStream::Controller(XmlStream::Controller::whatProlog);
}

inline const XmlStream::Controller tag() {
return XmlStream::Controller(XmlStream::Controller::whatTag);
}

inline const XmlStream::Controller tag(const char* const tag_name) {
 return XmlStream::Controller(XmlStream::Controller::whatTag, tag_name);
}

//BS, 08.11.2005
inline const XmlStream::Controller tag(const std::string tag_name) {
 return XmlStream::Controller(XmlStream::Controller::whatTag, 
                                                      tag_name.c_str());
}

inline const XmlStream::Controller endtag() {
        return XmlStream::Controller(XmlStream::Controller::whatTagEnd);
}

inline const XmlStream::Controller endtag(const char* const tag_name) {
 return 
     XmlStream::Controller(XmlStream::Controller::whatTagEnd, tag_name);
}

//BS, 08.11.2005
inline const XmlStream::Controller endtag(const std::string tag_name) {
 return XmlStream::Controller(XmlStream::Controller::whatTagEnd, 
                                                      tag_name.c_str());
}

inline const XmlStream::Controller attr(const char* const attr_name) {
 return XmlStream::Controller(XmlStream::Controller::whatAttribute, 
                                                             attr_name);
}

//BS, 08.11.2005
inline const XmlStream::Controller attr(const std::string attr_name) {
 return XmlStream::Controller(XmlStream::Controller::whatAttribute, 
                                                     attr_name.c_str());
}

inline const XmlStream::Controller chardata() {
      return XmlStream::Controller(XmlStream::Controller::whatCharData);
}


template<class X>
  void save (const std::string &filename, const X obj)
  {
    std::ofstream save_file (filename.c_str());
    if (save_file)
    {
      xmlw::XmlStream stream (save_file);
      stream << xmlw::prolog ();
      
      obj.save (stream);

      save_file.close ();
    }
  }

}       // end namespace xmlw
}       // end namespace BSUtilities

#endif  //  __XMLWRITER_H_2CC1D410_9DE8_4452_B8F0_F987EF152E06

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