/* $Id: OutputFilterNormalizeLinebreaks.h 403 2008-07-30 18:22:01Z rbock $ */

#ifndef UTILITY_INPUT_FILTER_NORMALIZE_LINEBREAKS_H
#define UTILITY_INPUT_FILTER_NORMALIZE_LINEBREAKS_H

// Binaries includes
#include <boost/iostreams/categories.hpp> // output_filter_tag
#include <boost/iostreams/operations.hpp> // put

namespace Utility
{

/** OutputFilterNormalizeLinebreaks
 *
 * Input filter for boost::iostreams::filtering_ostream
 *
 * Used for normalization of different linebreaks:
 *
 * \n     (unix)
 * \r\n   (dos/windows)
 * \r     (mac)
 * \r\r\n (result of binary upload and ascii download of dos encoded data via a dos/windows ftp server)
 *
 * Everything is normalized to 
 *
 * \n
 *
 * Usage like this:
 *
 * boost::iostreams::filtering_ostream correctedOutputStream;
 * correctedOutputStream.push(OutputFilterNormalizeLinebreaks());
 * correctedOutputStream.push(originalOutputStream);
 *                                     
 */
class OutputFilterNormalizeLinebreaks {
public:
   typedef char char_type;
   typedef boost::iostreams::output_filter_tag category;

   OutputFilterNormalizeLinebreaks()
      : hasCarriageReturn_(false) 
   { }

   template<typename Sink>
   bool put(Sink& sink, const char c)
   {
      if (c == '\r' || c == '\n')
      {
         if (hasCarriageReturn_ == false)
         {
            hasCarriageReturn_ = true;
            boost::iostreams::flush(sink);
            return boost::iostreams::put(sink, '\n');
         }
         return true;
      }

      hasCarriageReturn_ = false;

      return boost::iostreams::put(sink, c);
   }

   template<typename Sink>
   void close(Sink&);
private:
   bool hasCarriageReturn_;
};

} // namespace

#endif