ScaColData.h

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// # ScaColData.h: Access to a table column containing scalars
// # Copyright (C) 1994,1995,1996,1998,1999
// # 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
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#ifndef TABLES_SCACOLDATA_H
#define TABLES_SCACOLDATA_H
 
// # Includes
#include <casacore/casa/aips.h>
#include <casacore/casa/Arrays/ArrayFwd.h>
#include <casacore/tables/Tables/PlainColumn.h>
 
namespace casacore {  // # NAMESPACE CASACORE - BEGIN
 
// # Forward Declarations
class ColumnSet;
template <class T>
class ScalarColumnDesc;
class AipsIO;
 
// <summary>
// Access to a table column containing scalars
// </summary>
 
// <use visibility=local>
 
// <reviewed reviewer="Gareth Hunt" date="94Nov17" tests="">
// </reviewed>
 
// <prerequisite>
// # Classes you should understand before using this one.
//   <li> PlainColumn
//   <li> ScalarColumnDesc
//   <li> Table
// </prerequisite>
 
// <etymology>
// ScalarColumnData represents a table column containing scalars.
// </etymology>
 
// <synopsis>
// The class ScalarColumnData is derived from PlainColumn.
// It implements the virtual functions accessing a table column
// containing scalars with an arbitrary data type.
//
// It is possible to access an scalar an individual cell (i.e. table row)
// or in the entire column.
//
// The main task of this class is to communicate with the data manager
// column object. This consists of:
// <ul>
//  <li> Binding itself to a data manager.
//  <li> Letting the data manager create its column object.
//  <li> Closing the data manager column object (in putFileDerived).
//  <li> Reconstructing the data manager object for an existing table
//         (in getFileDerived).
//  <li> Transferring get/put calls to the data manager column object.
// </ul>
//
// The class is hidden from the user by the envelope class ScalarColumn.
// It used directly, it should be done with care. It assumes that the
// arrays in the various get and put functions have the correct length.
// ScalarColumn does that check.
// </synopsis>
 
// <todo asof="$DATE:$">
// # A List of bugs, limitations, extensions or planned refinements.
// </todo>
 
template <class T>
class ScalarColumnData : public PlainColumn {
 public:
  // Construct a scalar column object from the given description
  // in the given column set.
  // This constructor is used by ScalarColumnDesc::makeColumn.
  ScalarColumnData(const ScalarColumnDesc<T>*, ColumnSet*);
 
  ~ScalarColumnData();
 
  // Initialize the rows from startRownr till endRownr (inclusive)
  // with the default value defined in the column description.
  virtual void initialize(rownr_t startRownr, rownr_t endRownr);
 
  // Test if the given cell contains a defined value.
  virtual Bool isDefined(rownr_t rownr) const;
 
  // Get the value from a particular cell.
  virtual void get(rownr_t rownr, void*) const;
 
  // Get the array of all values in the column.
  // The length of the buffer pointed to by dataPtr must match
  // the actual length. This is checked by ScalarColumn.
  virtual void getScalarColumn(ArrayBase& dataPtr) const;
 
  // Get the array of some values in the column (on behalf of RefColumn).
  // The length of the buffer pointed to by dataPtr must match
  // the actual length. This is checked by ScalarColumn.
  virtual void getScalarColumnCells(const RefRows& rownrs, ArrayBase& dataPtr) const;
 
  // Put the value in a particular cell.
  // The length of the buffer pointed to by dataPtr must match
  // the actual length. This is checked by ScalarColumn.
  virtual void put(rownr_t rownr, const void* dataPtr);
 
  // Put the array of all values in the column.
  // The length of the buffer pointed to by dataPtr must match
  // the actual length. This is checked by ScalarColumn.
  virtual void putScalarColumn(const ArrayBase& dataPtr);
 
  // Put the array of some values in the column (on behalf on RefColumn).
  // The length of the buffer pointed to by dataPtr must match
  // the actual length. This is checked by ScalarColumn.
  virtual void putScalarColumnCells(const RefRows& rownrs, const ArrayBase& dataPtr);
 
  // Add the sort key to the Sort object on behalf of the Table sort function.
  // <group>
  virtual void makeSortKey(Sort&, std::shared_ptr<BaseCompare>& cmpFunc, Int order,
                           std::shared_ptr<ArrayBase>& dataSave);
  // Do it only for the given row numbers.
  void makeRefSortKey(Sort&, std::shared_ptr<BaseCompare>& cmpFunc, Int order,
                      const Vector<rownr_t>& rownrs, std::shared_ptr<ArrayBase>& dataSave);
  // </group>
 
  // Allocate value buffers for the table iterator.
  // Also get a comparison object if undefined.
  // The function freeIterBuf must be called to free the buffers.
  void allocIterBuf(void*& lastVal, void*& curVal, std::shared_ptr<BaseCompare>& cmpObj);
 
  // Free the value buffers allocated by allocIterBuf.
  void freeIterBuf(void*& lastVal, void*& curVal);
 
  // Create a data manager column object for this column.
  void createDataManagerColumn();
 
 private:
  // Pointer to column description.
  const ScalarColumnDesc<T>* scaDescPtr_p;
  // Undefined value can exist?
  Bool undefFlag_p;
  // Undefined value.
  T undefVal_p;
 
  // Copy constructor cannot be used.
  ScalarColumnData(const ScalarColumnData<T>&);
 
  // Assignment cannot be used.
  ScalarColumnData<T>& operator=(const ScalarColumnData<T>&);
 
  // Write the column data.
  // The control information is written into the given AipsIO object,
  // while the data is written/flushed by the data manager.
  void putFileDerived(AipsIO&);
 
  // Read the column data back.
  // The control information is read from the given AipsIO object.
  // This is used to bind the column to the appropriate data manager.
  // Thereafter the data manager gets opened.
  void getFileDerived(AipsIO&, const ColumnSet&);
 
  // Fill in the sort key on behalf of the Table sort function.
  // The pointer to the data (which can be allocated on the heap)
  // is stored in dataPtr. This is used by freeSortKey to release it.
  // It checks if a compare function is given when needed.
  // <thrown>
  //   <li> TableInvSort
  // </thrown>
  void fillSortKey(const Vector<T>* dataPtr, Sort&, std::shared_ptr<BaseCompare>& cmpObj,
                   Int order);
};
 
}  // namespace casacore
 
#ifndef CASACORE_NO_AUTO_TEMPLATES
#include <casacore/tables/Tables/ScaColData.tcc>
#endif  // # CASACORE_NO_AUTO_TEMPLATES
#endif