SSMIndColumn.h

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//# SSMIndColumn.h: A column in Standard storage manager for indirect arrays
//# Copyright (C) 2000
//# 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: aips2-request@nrao.edu.
//#        Postal address: AIPS++ Project Office
//#                        National Radio Astronomy Observatory
//#                        520 Edgemont Road
//#                        Charlottesville, VA 22903-2475 USA
//#
//# $Id$
 
#ifndef TABLES_SSMINDCOLUMN_H
#define TABLES_SSMINDCOLUMN_H
 
 
//# Includes
#include <casacore/casa/aips.h>
#include <casacore/tables/DataMan/SSMColumn.h>
#include <casacore/tables/DataMan/StIndArray.h>
#include <casacore/casa/Arrays/IPosition.h>
 
namespace casacore { //# NAMESPACE CASACORE - BEGIN
 
//# Forward Declarations
class StManArrayFile;
class AipsIO;
 
 
// <summary>
// A column of Standard storage manager for indirect arrays.
// </summary>
 
// <use visibility=local>
 
// <reviewed reviewer="UNKNOWN" date="before2004/08/25" tests="tStandardStMan.cc">
// </reviewed>
 
// <prerequisite>
//# Classes you should understand before using this one.
//   <li> <linkto class=SSMColumn>SSMColumn</linkto>
//   <li> <linkto class=StIndArray>StIndArray</linkto>
// </prerequisite>
 
// <etymology>
// SSMIndColumn represents a Column in the Standard Storage Manager
// containing Indirect arrays.
// </etymology>
 
// <synopsis> 
// SSMIndColumn is the implementation of an
// <linkto class=SSMColumn>SSMColumn</linkto> class
// to handle indirect arrays. The arrays (shape and data) are stored in
// a separate file using class <linkto class=StIndArray>StIndArray</linkto>.
// The file offset of the beginning of the array in stored in the
// appropriate data bucket using the standard SSMColumn functions.
// <p>
// Note that an indirect array can have a fixed shape. In that case
// adding a row results in reserving space for the array in the StIndArray
// file, so for each row an array is present.
// On the other hand adding a row does nothing for variable shaped arrays.
// So when no data is put or shape is set, a row may contain no array at all.
// In that case the function <src>isShapeDefined</src> returns False for
// that row.
// <p>
// Indirect arrays containing strings are not handled by this class, but
// by <linkto class=SSMIndStringColumn>SSMIndStringColumn</linkto>.
// That class stores those string arrays in the special string buckets
// instead of using StIndArray. The reason is that the string buckets
// are more disk space efficient when string arrays are frequently updated.
// </synopsis> 
 
//# <todo asof="$DATE:$">
//# A List of bugs, limitations, extensions or planned refinements.
//# </todo>
 
 
class SSMIndColumn : public SSMColumn
{
public:
  // Create a column of the given data type.
  // It keeps the pointer to its parent (but does not own it).
  SSMIndColumn (SSMBase* aParent, int aDataType, uInt aColNr);
  
  // Frees up the storage.
  ~SSMIndColumn();
  
  // An array of 'fixed length' strings is not handled specially,
  // thus this function is ignored.
  // It is needed to override the bahviour of the base class.
  virtual void setMaxLength (uInt maxLength);
 
  // Add (newNrrow-oldNrrow) rows to the column.
  virtual void addRow (rownr_t aNewNrRows, rownr_t anOldNrRows, Bool doInit);
  
  // Set the (fixed) shape of the arrays in the entire column.
  virtual void setShapeColumn (const IPosition& aShape);
  
  // Get the dimensionality of the item in the given row.
  virtual uInt ndim (rownr_t aRowNr);
  
  // Set the shape of the array in the given row and allocate the array
  // in the file.
  void setShape (rownr_t aRowNr, const IPosition& aShape);
  
  // Is the shape defined (i.e. is there an array) in this row?
  virtual Bool isShapeDefined (rownr_t aRowNr);
  
  // Get the shape of the array in the given row.
  virtual IPosition shape (rownr_t aRowNr);
  
  // This storage manager can handle changing array shapes.
  Bool canChangeShape() const;
  
  // Get an array value in the given row.
  // The buffer pointed to by dataPtr has to have the correct length
  // (which is guaranteed by the ArrayColumn get function).
  virtual void getArrayV (rownr_t aRowNr, ArrayBase& aDataPtr);
  
  // Put an array value into the given row.
  // The buffer pointed to by dataPtr has to have the correct length
  // (which is guaranteed by the ArrayColumn put function).
  virtual void putArrayV (rownr_t aRowNr, const ArrayBase& aDataPtr);
  
  // Get a section of the array in the given row.
  // The buffer pointed to by dataPtr has to have the correct length
  // (which is guaranteed by the ArrayColumn getSlice function).
  virtual void getSliceV (rownr_t aRowNr, const Slicer&,
                          ArrayBase& aDataPtr);
  
  // Put into a section of the array in the given row.
  // The buffer pointed to by aDataPtr has to have the correct length
  // (which is guaranteed by the ArrayColumn putSlice function).
  virtual void putSliceV (rownr_t aRowNr, const Slicer&,
                          const ArrayBase& aDataPtr);
  
  // Let the column object create its array file.
  virtual void doCreate (rownr_t aNrRows);
 
  // Open an existing file.
  virtual void getFile (rownr_t aNrRows);
 
  // Remove the given row from the data bucket and possibly string bucket.
  virtual void deleteRow(rownr_t aRowNr);
 
 
private:
  // Forbid copy constructor.
  SSMIndColumn (const SSMIndColumn&);
  
  // Forbid assignment.
  SSMIndColumn& operator= (const SSMIndColumn&);
  
  // Initialize part of the object and open/create the file.
  // It is used by doCreate and getFile.
  void init();
  
  // Read the shape at the given row.
  // This will cache the information in the StIndArray
  // object for that row.
  StIndArray* getShape (rownr_t aRowNr);
  
  // Return a pointer to the array in the given row (for a get).
  StIndArray* getArrayPtr (rownr_t aRowNr);
 
  
  //# The shape off all arrays in case it is fixed
  IPosition       itsFixedShape;
  //# Switch indicating if the shape is fixed.
  Bool            isShapeFixed;
  //# The file containing the arrays.
  StManArrayFile* itsIosFile;
  //# The indirect array object.
  StIndArray      itsIndArray;
};
 
 
 
} //# NAMESPACE CASACORE - END
 
#endif