AbstractFile.H

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/*---------------------------------------------------------------------+
 | Library QgarLib, graphics analysis and recognition                  |
 | Copyright (C) 2002  Qgar Project, LORIA                             |
 |                                                                     |
 | This library is free software; you can redistribute it and/or       |
 | modify it under the terms of the GNU Lesser General Public          |
 | License version 2.1, as published by the Free Software Foundation.  |
 |                                                                     |
 | 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.         |
 |                                                                     |
 | The GNU Lesser General Public License is included in the file       |
 | LICENSE.LGPL, in the root directory of the Qgar packaging. See      |
 | http://www.gnu.org/licenses/lgpl.html for the terms of the licence. |
 | To receive a paper copy, write to the Free Software Foundation,     |
 | Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.       |
 |                                                                     |
 | Contact Project Qgar for any information:                           |
 |   LORIA - équipe Qgar                                               |
 |   B.P. 239, 54506 Vandoeuvre-lès-Nancy Cedex, France                |
 |   email: qgar-contact@loria.fr                                      |
 |   http://www.qgar.org/                                              |
 *---------------------------------------------------------------------*/


#ifndef __ABSTRACTFILE_H_INCLUDED__
#define __ABSTRACTFILE_H_INCLUDED__


/**
 * @file   AbstractFile.H
 * @brief  Header file of class qgar::AbstractFile.
 *
 * @author <a href="mailto:qgar-develop@loria.fr?subject=Qgar fwd Gérald Masini">Gérald Masini</a>
 * @date   Jul 02, 2001  17:13
 * @since  Qgar 1.0
 */


// For RCS/CVS use: Do not delete
/* $Id: AbstractFile.H,v 1.15 2005/07/13 16:29:00 masini Exp $ */



// STL
#include <fstream>
// QGAR
#include <qgarlib/QgarErrorIO.H>
#include <qgarlib/QgarErrorInvalidArg.H>
#include <qgarlib/QgarErrorUser.H>



namespace qgar
{


// -------------------------------------------------------------------
// T Y P E S   R E L A T E D   T O   F I L E S
// -------------------------------------------------------------------

/**
 * @name Types related to files
 * @ingroup IO_FILE
 */

/**
 * @brief File status.
 */
enum QGEfileStatus
{
QGE_FILE_STATUS_CLOSED,
QGE_FILE_STATUS_READ_ONLY,
QGE_FILE_STATUS_WRITE_ONLY,
QGE_FILE_STATUS_APPEND,
QGE_FILE_STATUS_READ_WRITE,
QGE_FILE_STATUS_READ_APPEND
};

//@}

// -------------------------------------------------------------------
// E N D   O F   T Y P E S   R E L A T E D   T O   F I L E S
// -------------------------------------------------------------------




/**
 * @class AbstractFile AbstractFile.H "qgarlib/AbstractFile.H"
 * @ingroup IO_FILE
 * @brief Base class implementing common tools to conveniently
 *        define and use files in the Qgar way.
 * 
 * @warning
 * This is an abstract class.
 * Pure virtual functions:
 * - qgar::AbstractFile::readHeader
 * - qgar::AbstractFile::writeHeader
 * - qgar::AbstractFile::writeFooter
 *
 * @author   <a href="mailto:qgar-develop@loria.fr?subject=Qgar fwd Gérald Masini">Gérald Masini</a>
 * @date     Jul 02, 2001  17:13
 * @since    Qgar 1.0
 */
class AbstractFile
{
// -------------------------------------------------------------------
// P U B L I C    M E M B E R S
// -------------------------------------------------------------------
public:

  /** @name Destructor */
  //        ==========
  //@{

  /**
   * @brief Virtual destructor.
   *
   * Free space allocated to character string representing
   * the name of the file
   */
  virtual ~AbstractFile();

  //@}


  /** @name Access to file characteristics */
  //        ==============================
  //@{

  /**
   * @brief Get file stream.
   *
   * When saving the stream, usual I/O operations apply to the
   * associated file, depending on the opening mode.
   */
  inline std::fstream& fileStream();

  /**
   * @brief Get file name.
   */
  inline const char* const fileName() const;

  /**
   * @brief Get current file status.
   */
  inline QGEfileStatus fileStatus() const;

  //@}


  /** @name Opening */
  //        =======
  //@{

  /**
   * @brief Open in <b>read-only</b> mode.
   *
   * The file pointer is set to the first character after the header.
   *
   * @warning The file header is read using function
   * qgar::AbstractFile::readHeader.
   *
   * @exception qgar::QgarErrorIO (file cannot be opened)
   */
  virtual void openRONLY() throw(QgarErrorIO);

  /**
   * @brief Open in <b>write-only</b> mode.
   *
   * @warning The file is new and a header is written into the
   * file using function qgar::AbstractFile::writeHeader.
   * If a file with given name already exists, its content is lost.
   *
   * @exception qgar::QgarErrorIO (file cannot be opened)
   */
  virtual void openWONLY() throw(QgarErrorIO);

  /**
   * @brief Open in <b>append</b> mode.
   *
   * The eventual content of the file is preserved and the file pointer
   * is set to the end of the file.
   *
   * @warning The file header is read using function
   * qgar::AbstractFile::readHeader.
   *
   * @exception qgar::QgarErrorIO (file cannot be opened)
   */
  virtual void openAPPEND() throw(QgarErrorIO);

  /**
   * @brief Open in <b>read-write</b> mode.
   *
   * @warning The file is new and a header is written into the
   * file using function qgar::AbstractFile::writeHeader.
   * If a file with given name already exists, its content is lost.
   *
   * @exception qgar::QgarErrorIO (file cannot be opened)
   */
  virtual void openRW() throw(QgarErrorIO);

  /**
   * @brief Open in <b>read-append</b> mode.
   *
   * The file pointer is set to the end of the file.
   *
   * @warning The file header is read using function
   * qgar::AbstractFile::readHeader.
   *
   * @exception qgar::QgarErrorIO (file cannot be opened)
   */
  virtual void openRA() throw(QgarErrorIO);

  //@}


  /** @name Closing */
  //        =======
  //@{

  /**
   * @brief Close the file.
   *
   * No effect is the file is already closed.
   *
   * @warning If the file is currently open in <b>write-only</b>
   * or <b>read-write</b> modes, a footer is written into the file
   * using function qgar::AbstractFile::writeFooter.
   */
  virtual void close();

  //@}


  /** @name Checking status */
  //        ===============
  //@{

  /**
   * @brief Abort if the file is not open
   *   in a mode allowing reading.
   *
   * @exception qgar::QgarErrorUser (file not open in read mode)
   */
  virtual void isOpenR() throw(QgarErrorUser);
 
 /**
   * @brief Abort if the file is not open
   *   in a mode allowing writing.
   *
   * @exception qgar::QgarErrorUser (file not open in write mode)
   */
  virtual void isOpenW() throw(QgarErrorUser);

  /**
   * @brief Abort if the file is not open
   *  in a mode allowing appending.
   *
   * @exception qgar::QgarErrorUser (file not open in append mode)
   */
  virtual void isOpenA() throw(QgarErrorUser);

  /**
   * @brief Abort if the file is not open
   *   in <b>read-write</b> mode.
   *
   * @exception qgar::QgarErrorUser (file not open in read/write mode)
   */
  virtual void isOpenRW() throw(QgarErrorUser);

  /**
   * @brief Abort if the file is not open
   *   in <b>readi-append</b> mode.
   *
   * @exception qgar::QgarErrorUser (file not open in read/append mode)
   */
  virtual void isOpenRA() throw(QgarErrorUser);

  //@}


// -------------------------------------------------------------------
// P R O T E C T E D    M E M B E R S
// -------------------------------------------------------------------
protected:

  //  ============================================
  /** @name Constructors
      Constructors belong to the protected section
      so that the class cannot be instantiated.
   */
  //  ============================================
  //@{

  /**
   * @brief Create a file of given name.
   * @param aFileName name of the file
   *
   * @warning The file is closed and must be opened to be used.
   *
   * @exception qgar::QgarErrorInvalidArg (incorrect file name)
   */
  AbstractFile(const char* aFileName) throw(QgarErrorInvalidArg);

  //@}


  /** @name Headers & footers */
  //        =================
  //@{

  /**
   * @brief Read header of the file (pure virtual function).
   *
   * Automatically performed when the file is opened for reading,
   * appending or reading/appending.
   */
  virtual void readHeader() = 0;

  /**
   * @brief Write header of the file (pure virtual function).
   *
   * Automatically performed when the file is opened for writing only
   * or reading/writing.
   */
  virtual void writeHeader() = 0;

  /**
   * @brief Write footer of the file (pure virtual function).
   *
   * Automatically performed when the file is closed.
   */
  virtual void writeFooter() = 0;

  //@}


  /** @name Representation of a file */
  //        ========================
  //@{

  /**
   * @brief File name.
   */
  char* _fileName;

  /**
   * @brief File status.
   */
  QGEfileStatus _fileStatus;

  /**
   * @brief Associated file stream.
   */
  std::fstream _fileStream;

  //@}


// -------------------------------------------------------------------

}; // class AbstractFile




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// ==============================
// ACCESS TO FILE CHARACTERISTICS
// ==============================


// GET FILE STREAM

inline std::fstream&
AbstractFile::fileStream()
{
  return _fileStream;
}


// GET FILE NAME

inline const char* const
AbstractFile::fileName() const
{
  return _fileName;
}


// GET CURRENT FILE STATUS

inline QGEfileStatus
AbstractFile::fileStatus() const
{
  return _fileStatus;
}


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} // namespace qgar 


#endif /* __ABSTRACTFILE_H_INCLUDED__ */