text: // $Id: InputFileStream.h 2939 2010-02-24 11:15:44Z jfouet $
  
  /***********************************************************************
   Moses - factored phrase-based language decoder
   Copyright (C) 2006 University of Edinburgh
  
   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 2.1 of the License, or (at your option) any later version.
  
   This library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.
  
   You should have received a copy of the GNU Lesser General Public
   License along with this library; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
   ***********************************************************************/
  
  #pragma once
  
  #include <cstdlib>
  #include <fstream>
  #include <string>
  #include <iostream>
  #include <boost/iostreams/filtering_stream.hpp>
  
  namespace Moses
  {
  
  /** Version of std::ostream with transparent compression.
   *
   * Transparently compresses output when writing to a file whose name ends in
   * ".gz".  Or, writes to stdout instead of a file when given a filename
   * consisting of just a dash ("-").
   */
  class OutputFileStream : public boost::iostreams::filtering_ostream
  {
  private:
    /** File that needs flushing & closing when we close this stream.
     *
     * Is NULL when no file is opened, e.g. when writing to standard output.
     */
    std::ofstream *m_outFile;
  
    /// Is this stream open?
    bool m_open;
  
  public:
    /** Create an unopened OutputFileStream.
     *
     * Until it's been opened, nothing can be done with this stream.
     */
    OutputFileStream();
  
    /// Create an OutputFileStream, and open it by calling Open().
    OutputFileStream(const std::string &filePath);
    virtual ~OutputFileStream();
  
    // TODO: Can we please just always throw an exception when this fails?
    /** Open stream.
     *
     * If filePath is "-" (just a dash), this opens the stream for writing to
     * standard output.  Otherwise, it opens the given file.  If the filename
     * has the ".gz" suffix, output will be transparently compressed.
     *
     * Call Close() to close the file.
     *
     * Returns whether opening the file was successful.  It may also throw an
     * exception on failure.
     */
    bool Open(const std::string &filePath);
  
    /// Flush and close stream.  After this, the stream can be opened again.
    void Close();
  };
  
  }
  
  