//Purpose:
//  Explore differences in ways iostreams filtering is done
//  with different device types.
//Acknowledgements:
//  Original code from post:
/*
From: Ken Appleby <ken.appleby@btopenworld.com>
Newsgroups: gmane.comp.lib.boost.user
Subject: Re: [iostreams] How can I use the Stream Insertion
 operator (<<) with a filtering_streambuf?
Date: Fri, 26 Jul 2013 18:06:47 +0100
Lines: 94
*/
//ChangeLog:
//  2013-07-29.0847
//    Converted to use:
//      filtering_estream 
//    instead of:
//      filtering_streambuf
//    after reading post:
/*
From: Stephen Greenfield <StephenG@screenplay.com>
Newsgroups: gmane.comp.lib.boost.user
Subject: Re: [iostreams] How can I use the Stream Insertion
 operator (<<) with a filtering_streambuf?
Date: Mon, 29 Jul 2013 04:28:04 +0000
Lines: 167
 */
//==========================
#include <iostream>
#define USE_STRINGSTRM //use stringstream instead of fstream.
#ifdef USE_STRINGSTRM
#include <sstream>
#else
#include <fstream>
#endif

#include <boost/iostreams/filtering_stream.hpp>
#include <boost/iostreams/copy.hpp>
#define USE_FILT_COMPRESS
#ifdef USE_FILT_COMPRESS
#include <boost/iostreams/filter/gzip.hpp>
#else
#include <boost/ref.hpp>
#include <boost/iostreams/filter/counter.hpp>
#endif

int main()
{
    std::cout<<"USE_STRINGSTRM="
    #ifdef USE_STRINGSTRM
      <<"yes defined"
    #else
      <<"not defined"
    #endif
      <<"\n";
    std::cout<<"USE_FILT_COMPRESS="
    #ifdef USE_FILT_COMPRESS
      <<"yes defined"
    #else
      <<"not defined"
    #endif
      <<"\n";
    std::ios::openmode const ios_binary=
        std::ios::binary
        ;
    std::cout<<"ios_binary="<<ios_binary<<"\n";
    try
    {
      #ifdef USE_STRINGSTRM
        std::string strmValue;
      #else
        char const*filePath="hello.gz";
      #endif
        {
          std::ios::openmode const ios_mode=ios_binary | std::ios::out;
          #ifdef USE_STRINGSTRM
            std::ostringstream myOstrm( strmValue, ios_mode );
          #else
            std::ofstream      myOstrm( filePath , ios_mode );
          #endif
            boost::iostreams::filtering_ostream out;
          #ifdef USE_FILT_COMPRESS
            boost::iostreams::gzip_compressor filter;
          #else
            boost::iostreams::counter filter_val;
            boost::reference_wrapper<boost::iostreams::counter> filter(filter_val);
          #endif
            out.push( filter  );
            out.push( myOstrm );
            out << "text to be in the file...";
          #ifdef USE_STRINGSTRM
            out.flush();
            strmValue=myOstrm.str();
          #endif
          #ifdef USE_FILT_COMPRESS
          #else
            std::cout<<"characters="<<filter_val.characters()<<"\n";
          #endif
        }
      #ifdef USE_STRINGSTRM
        std::cout<<"strmValue="<<strmValue<<"\n";
      #endif
        {
          std::ios::openmode const ios_mode=ios_binary | std::ios::in;
          #ifdef USE_STRINGSTRM
            std::istringstream myIstrm( strmValue, ios_mode);
          #else
            std::ifstream      myIstrm( filePath , ios_mode);
          #endif
            boost::iostreams::filtering_istream inp;
          #ifdef USE_FILT_COMPRESS
            boost::iostreams::gzip_decompressor filter;
          #else
            boost::iostreams::counter filter_val;
            boost::reference_wrapper<boost::iostreams::counter> filter(filter_val);
          #endif
            inp.push( filter  );
            inp.push( myIstrm );
            std::string text;
            unsigned count=0;
            while ( inp.good() )
            {
                char ch = inp.get();
                int ic=ch;
                ++count;
                std::cout<<"get["<<count<<"]="<<ch<<"=(int)"<<ic<< std::endl << std::flush;
                if ( inp.good() )
                {
                    text.push_back( ch );
                }
            }
            std::cout << "count="<<count<< std::endl <<std::flush;
            std::cout << "text from file is \"" << text << "\"" << std::endl << std::flush;
          #ifdef USE_FILT_COMPRESS
          #else
            std::cout<<"characters="<<filter_val.characters()<<"\n";
          #endif
        }
    } catch ( std::exception& e )
    {
        std::cerr << e.what() << std::endl;
    }
}