HfstOutputStream.h

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// Copyright (c) 2016 University of Helsinki                          
//                                                                    
// This library is free software; you can redistribute it and/or      
// modify it under the terms of the GNU Lesser General Public         
// License as published by the Free Software Foundation; either       
// version 3 of the License, or (at your option) any later version.
// See the file COPYING included with this distribution for more      
// information.

#ifndef _HFST_OUTPUTSTREAM_H_
#define _HFST_OUTPUTSTREAM_H_

#if HAVE_CONFIG_H
#  include <config.h>
#endif

#include "HfstDataTypes.h"

#include "hfstdll.h"

namespace hfst
{

  namespace implementations {
#if HAVE_OPENFST
#if HAVE_OPENFST_LOG
    class LogWeightOutputStream;
#endif
    class TropicalWeightOutputStream;
#endif
#if HAVE_SFST
    class SfstOutputStream;
#endif
#if HAVE_FOMA
    class FomaOutputStream;
#endif    
#if HAVE_XFSM
    class XfsmOutputStream;
#endif    
#if HAVE_MY_TRANSDUCER_LIBRARY
    class MyTransducerLibraryOutputStream;
#endif
    class HfstOlOutputStream;
  }


  class HfstOutputStream
  {
  protected:
    union StreamImplementation
    {
#if HAVE_OPENFST
#if HAVE_OPENFST_LOG
      hfst::implementations::LogWeightOutputStream * log_ofst;
#endif
      hfst::implementations::TropicalWeightOutputStream * tropical_ofst;
#endif
#if HAVE_SFST
      hfst::implementations::SfstOutputStream * sfst;
#endif
#if HAVE_FOMA
      hfst::implementations::FomaOutputStream * foma;
#endif
#if HAVE_XFSM
      hfst::implementations::XfsmOutputStream * xfsm;
#endif

#if HAVE_MY_TRANSDUCER_LIBRARY
      hfst::implementations::MyTransducerLibraryOutputStream * 
        my_transducer_library;
#endif

      hfst::implementations::HfstOlOutputStream * hfst_ol;
    };
    ImplementationType type; // type of the stream implementation
    // whether an hfst header is written before every transducer
    bool hfst_format;  
    StreamImplementation implementation; // backend implementation

    // write data to stream
    void write(const std::string &s);
    void write(const std::vector<char> &s);
    void write(const char &c);

    // if file is open
    bool is_open;

    // append string s to vector str and a '\0'
    static void append(std::vector<char> &str, const std::string &s);

    // append obligatory HFST header data to \a header
    void append_hfst_header_data(std::vector<char> &header);
    /* append implementation-specific header data collected from 
       \a transducer to \a header */
    void append_implementation_specific_header_data
      (std::vector<char> &header, HfstTransducer &transducer);


  public:

    HFSTDLL HfstOutputStream(ImplementationType type, bool hfst_format=true);

    HFSTDLL HfstOutputStream(const std::string &filename, ImplementationType type, bool hfst_format=true);

    HFSTDLL ~HfstOutputStream(void);  

    HFSTDLL HfstOutputStream &flush();

    HFSTDLL HfstOutputStream &operator<< (HfstTransducer &transducer);

    HFSTDLL HfstOutputStream& redirect (HfstTransducer &transducer);

    HFSTDLL void close(void);
  };




}



#endif