AttValPoiTol.h

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//# AttValPoiTol.h: template for tolerant and aliased AttributeValues
//# Copyright (C) 1996,1997,1999,2000,2001
//# 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
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//#
//# $Id$

#ifndef TRIALDISPLAY_ATTVALPOITOL_H
#define TRIALDISPLAY_ATTVALPOITOL_H

#include <casa/aips.h>
#include <display/Display/AttValTol.h>

namespace casa { //# NAMESPACE CASA - BEGIN

// <summary> 
// Templated class for aliased, tolerant AttributeValues.
// </summary>

// <use visibility=local>
 
// <reviewed reviewer="" date="yyyy/mm/dd" tests="tAttribute" demos="">
// </reviewed>

// <prerequisite>
// <li> <linkto class="AttributeValue">AttributeValue</linkto>
// <li> <linkto class="AttributeValuePoi">AttributeValuePoi</linkto>
// <li> <linkto class="AttributeValueTol">AttributeValueTol</linkto>
// </prerequisite>

// <etymology> 
// "AttributeValuePoiTol" is a contraction of "Attribute Value", 
// "Pointer" and "Tolerance", and stores an Attribute by aliasing
// it with a pointer and associating it with some tolerance.
// </etymology>

// <synopsis>
// An AttributeValuePoiTol combines the aliasing (via a pointer)
// provided by the <linkto class="AttributeValuePoi">
// AttributeValuePoi </linkto> class, and the tolerance provided by
// the <linkto class="AttributeValueTol"> AttributeValueTol </linkto>
// class.  See these classes for examples.
// </synopsis>

// <motivation> 
// The motivation for this class is to be able to provide in-built
// tolerance and aliasing for AttributeValues.
// </motivation>

// <todo asof="2000/01/17">
// </todo>

template <class T> class AttributeValuePoiTol : public AttributeValueTol<T> {

 public:

  // Constructor for a pointer to a scalar, and a tolerance.
  AttributeValuePoiTol(T* value, const T &tolerance, const Bool strict);

  // Constructor for a pointer to a <src>Vector</src>, and a scalar
  // tolerance.
  AttributeValuePoiTol(Vector<T>* value, const T &tolerance, 
                       const Bool strict);
  
  // Copy constructor.
  AttributeValuePoiTol(const AttributeValuePoiTol<T> &other);

  // Destructor.
  virtual ~AttributeValuePoiTol();

  // Assignment operator.
  const AttributeValuePoiTol<T>& operator=(const AttributeValuePoiTol<T> &other);

  // Return a new copy of the AttributeValuePoiTol (virtual constructor).
  virtual AttributeValueBase *clone() const;

  // Add <src>other</src> to <src>*this</src>.  Needs to over-ride
  // base class definition because the pointers need to be 
  // dereferenced prior to addition.
  virtual void operator+=(const AttributeValueBase &other);


  // Change the value of the AttributeValue.
  // <group>
  virtual void setValue(const T& value);
  virtual void setValue(const Vector<T>& value);
  // </group>

  // Get the DataType of the aliased variable.
  virtual DataType getPointerType() const;

  // Return class name
  virtual String className() const {return String("AttributeValuePoiTol");};

 private:

  // Update the variable that is aliased to the AttributeValuePoiTol.
  void updatePointerValue() const;
  
  // Pointer to the aliased variable. Only one is ever active depending
  // upon how the object was constructed.  The memory allocated to these pointers
  // does not belong to this object.
  // <group>
  Vector<T>* itsVectorPointerPtr;
  T* itsScalarPointerPtr;
  // </group>

  // The pointer DataType
  DataType itsPointerType;   

  // Cast from Base class
  const AttributeValuePoiTol<T>& myCast (const AttributeValueBase& other) const;

  // Default constructor  
  AttributeValuePoiTol();
  

  //# Make parent members known.
public:
  using AttributeValueTol<T>::getType;
  using AttributeValueTol<T>::getValue;
  using AttributeValueTol<T>::getStrictness;
};


} //# NAMESPACE CASA - END
#ifndef AIPS_NO_TEMPLATE_SRC
#include <display/Display/AttValPoiTol.tcc>
#endif
#endif