TVec.h

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// # TVec.h: Templated base class for table vectors
// # Copyright (C) 1994,1995,1999
// # 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
// #                        520 Edgemont Road
// #                        Charlottesville, VA 22903-2475 USA
 
#ifndef TABLES_TVEC_H
#define TABLES_TVEC_H
 
// # Includes
#include <casacore/casa/aips.h>
#include <casacore/casa/Arrays/Vector.h>
 
namespace casacore {  // # NAMESPACE CASACORE - BEGIN
 
// <summary>
// Enumeration of possible table vectors
// </summary>
// <reviewed reviewer="UNKNOWN" date="before2004/08/25" tests="">
// </reviewed>
// <use visibility=local>
// <synopsis>
// Define the type of table vectors.
// Alas, this enum has to be defined outside the class, because
// some compilers do not support an enum in a templated class.
// </synopsis>
// <group name=enum>
enum TabVecTag {
  // Table Vector is a scalar column
  TagScaCol = 1,
  // Table Vector is a temporary vector (i.e. a regular vector).
  TagTemp = 2
};
// </group>
 
// <summary>
// Templated base class for table vectors
// </summary>
 
// <use visibility=local>
 
// <reviewed reviewer="UNKNOWN" date="before2004/08/25" tests="">
// </reviewed>
 
// <prerequisite>
// # Classes you should understand before using this one.
//   <li> TableVector
// </prerequisite>
 
// <etymology>
// TabVecRep is the representation of a table vector.
// </etymology>
 
// <synopsis>
// TabVecRep is the counted referenced letter class for the envelope
// class TableVector. It is an abstract base class for the actual
// table vector classes TabVecScaCol and TabVecTemp.
//
// All operations defined for TableVector are immediately passed to
// the corresponding virtual TabVecRep function.
// The header files TVecMath.h and TVecLogic.h declare all the
// mathematical and logical functions for TabVecRep.
// </synopsis>
 
// <motivation>
// A virtual function call only works when used with an object
//  pointer or reference. To allow the use of virtual functions
// in value objects, an extra level of indirection is used.
// This is called the letter/envelope idiom and is described in
// "Advanced C++" by J. Coplien.
// Class TableVector is the envelope to the letters TabVecRep and
// its derivations.
// </motivation>
 
// <todo asof="$DATE:$">
// # A List of bugs, limitations, extensions or planned refinements.
//   <li> put the TabVecTag enum inside the class definition
//   <li> support array columns
// </todo>
 
template <class T>
class TabVecRep {
 public:
  // Create empty table vector.
  // TabVecRep cannot be contructed by the user, because it is an
  // abstract base class (it contains pure virtual functions).
  TabVecRep();
 
  // Destruct the object.
  virtual ~TabVecRep();
 
  // Get nr of dimensions.
  inline uInt ndim() const;
 
  // Get nr of elements (ie. vector length).
  inline rownr_t nelements() const;
 
  // Test if vector shape conforms another table vector.
  inline Bool conform(const TabVecRep<T>&) const;
 
  // Test if vector shape conforms another vector.
  inline Bool conform(const Vector<T>&) const;
 
  // Check internal consistency.
  Bool ok() const;
 
  // Increments the reference count.
  inline TabVecRep<T>* link();
 
  // Decrements the reference count and returns the resulting count.
  inline uInt unlink();
 
  // Get the tag (the type of vector).
  inline TabVecTag getTag() const;
 
  // Get a value.
  virtual T value(rownr_t index) const = 0;
 
  // Get a value.
  virtual void getVal(rownr_t index, T&) const = 0;
 
  // Put a value.
  virtual void putVal(rownr_t index, const T&) = 0;
 
  // Set entire vector to a value.
  virtual void set(const T&) = 0;
 
  // Set to another table vector.
  virtual void assign(const TabVecRep<T>&);
 
 protected:
  uInt count_p;  // # reference count
  TabVecTag tag_p;
  Int64 nrel_p;  // # #elements (<0 = ask derived class)
 
  // Get nr of elements.
  virtual rownr_t nelem() const;
 
 public:
  // Check if vectors are comformant.
  void validateConformance(rownr_t) const;
 
  // Create a new temporary vector (for result of math operations).
  // TabVecTemp<T>& cannot be used, because the template instantiation
  // mechanism instantiates TabVecTemp, which depends on TabVecRep and
  // therefore gives errors.
  void* newVec() const;
};
 
template <class T>
inline uInt TabVecRep<T>::ndim() const {
  return 1;
}
 
template <class T>
inline rownr_t TabVecRep<T>::nelements() const {
  return (nrel_p < 0 ? nelem() : nrel_p);
}
 
// # Check if 2 table vectors are conformant.
template <class T>
inline Bool TabVecRep<T>::conform(const TabVecRep<T>& vec) const {
  return (nelements() == vec.nelements() ? True : False);
}
template <class T>
inline Bool TabVecRep<T>::conform(const Vector<T>& vec) const {
  return (nelements() == vec.nelements() ? True : False);
}
 
// # Maintain reference count.
template <class T>
inline TabVecRep<T>* TabVecRep<T>::link() {
  count_p++;
  return this;
}
template <class T>
inline uInt TabVecRep<T>::unlink() {
  return --count_p;
}
 
// # Return the tag.
template <class T>
inline TabVecTag TabVecRep<T>::getTag() const {
  return tag_p;
}
 
}  // namespace casacore
 
#ifndef CASACORE_NO_AUTO_TEMPLATES
#include <casacore/tables/Tables/TVec.tcc>
#endif  // # CASACORE_NO_AUTO_TEMPLATES
#endif