HDF5File.h

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// # HDF5File.h: An class representing an HDF5 file
// # Copyright (C) 2008
// # Associated Universities, Inc. Washington DC, USA.
// #
// # This library is free software; you can redistribute it and/or modify it
// # under the terms of the GNU Library General Public License as published by
// # the Free Software Foundation; either version 2 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 Library General Public
// # License for more details.
// #
// # You should have received a copy of the GNU Library General Public License
// # along with this library; if not, write to the Free Software Foundation,
// # Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
// #
// # Correspondence concerning AIPS++ should be addressed as follows:
// #        Internet email: casa-feedback@nrao.edu.
// #        Postal address: AIPS++ Project Office
// #                        National Radio Astronomy Observatory
// #                        520 Edgemont Road
// #                        Charlottesville, VA 22903-2475 USA
 
#ifndef CASA_HDF5FILE_H
#define CASA_HDF5FILE_H
 
// # Includes
#include <casacore/casa/aips.h>
#include <casacore/casa/HDF5/HDF5Object.h>
#include <casacore/casa/BasicSL/String.h>
#include <casacore/casa/IO/ByteIO.h>
 
namespace casacore {  // # NAMESPACE CASACORE - BEGIN
 
// <summary>
// A class representing an HDF5 file.
// </summary>
 
// <use visibility=export>
 
// <reviewed reviewer="" date="" tests="tHDF5File.cc">
// </reviewed>
 
// <prerequisite>
//   <li> <a href="http://hdf.ncsa.uiuc.edu">HDF5 system</a>
// </prerequisite>
 
// <synopsis>
// This class wraps the HDF5 functions to open, create, or close an
// HDF5 file.
// If the file is opened as readonly, it is possible to reopen it for
// read/write (provided the user has the correct privileges).
// It is also possible to temporarily close the file and reopen it later.
// <note> It is ensured that the class and the static function <tt>isHDF5</tt>
// are also defined if HDF5 is not compiled in. </note>
// </synopsis>
 
// <motivation>
// It was overkill to use the HDF5 C++ interface. Instead little wrappers
// have been written. HDF5File can be embedded in a shared pointer making
// it possible to share an HDF5 file amongst various HDF5Array objects.
// </motivation>
 
class HDF5File : public HDF5Object {
 public:
  // Create an HDF5 file object with the given file name (possible tilde
  // or environment variables in it will be expanded).
  // The ByteIO option determines if the file will be created,
  // opened for input and/or output, or possibly deleted by the destructor.
  explicit HDF5File(const String& name, ByteIO::OpenOption = ByteIO::Old);
 
  // The destructor closes the file and deletes it when it was opened
  // using ByteIO::Scratch or ByteIO::Delete.
  ~HDF5File();
 
  // Test if the file with the given name is an HDF5 file.
  static Bool isHDF5(const String& name);
 
  // Reopen the underlying file for read/write access.
  // Nothing will be done if the stream is writable already.
  // Otherwise it will be reopened and an exception will be thrown
  // if it is not possible to reopen it for read/write access.
  void reopenRW();
 
  // Is the file writable?
  Bool isWritable() const { return itsOption == ByteIO::Update; }
 
  // Is the file opened for delete?
  Bool isOpenedForDelete() const { return itsDelete; }
 
  // Is the file temporarily closed?
  Bool isClosed() const { return getHid() < 0; }
 
  // Close the file (temporarily).
  // Note it will not delete the file; that is only done by the destructor.
  virtual void close();
 
  // Reopen the file if closed (which may change the HID).
  void reopen();
 
  // Flush the data to disk.
  void flush();
 
  // Get or set the chunk cache size (in bytes).
  // Note that all data sets in a file share the cache.
  // <group>
  size_t getChunkCacheSize() const;
  void setChunkCacheSize(size_t nbytes);
  // </group>
 
 private:
  // Open or create the file.
  void doOpen();
 
  // # Data members
  ByteIO::OpenOption itsOption;
  String itsName;
  Bool itsDelete;
 
 private:
  // Copy constructor cannot be used.
  HDF5File(const HDF5File& that);
 
  // Assignment cannot be used.
  HDF5File& operator=(const HDF5File& that);
};
 
}  // namespace casacore
 
#endif