UnitName.h

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// # UnitName.h: defines a tagged unit definition
// # Copyright (C) 1994,1995,1996,1997,1998,1999,2000,2001
// # 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: casa-feedback@nrao.edu.
// #        Postal address: AIPS++ Project Office
// #                        National Radio Astronomy Observatory
// #                        520 Edgemont Road
// #                        Charlottesville, VA 22903-2475 USA
 
#ifndef CASA_UNITNAME_H
#define CASA_UNITNAME_H
 
// # Includes
#include <casacore/casa/aips.h>
#include <casacore/casa/BasicSL/String.h>
#include <casacore/casa/Quanta/Unit.h>
#include <casacore/casa/Quanta/UnitVal.h>
#include <casacore/casa/iosfwd.h>
 
namespace casacore {  // # NAMESPACE CASACORE - BEGIN
 
// <summary>
// handles physical units
// </summary>
 
// <use visibility=export>
 
// <reviewed reviewer="UNKNOWN" date="before2004/08/25" tests="tUnit">
//
// <prerequisite>
// You should have at least a preliminary understanding of these classes:
//   <li> <linkto class=Unit>Unit</linkto>
// </prerequisite>
//
// <etymology>
// The class name derives from the basic Unit and the Name giving possibilities
// of this class to a newly defined unit tag.
// </etymology>
//
// <synopsis>
// Physical units are strings consisting of one or more names of known
// basic units, separated by '.' or ' ' (for multiplication) or '/' (for
// division). Each name can optionally be preceded by a standard decimal
// prefix, and/or followed by an (optionally signed) exponent.
//
// Example:
//  km/s/(Mpc.s)2  is identical to km.s-1.Mpc-2.s-2
//
// See the <linkto class="Unit">Unit</linkto> class for more details.
//
// The UnitName class defines new basic, tagged units. If, e.g., for one
// reason or another you want, in addition to the standard defined SI and
// customary units, to define a unit with a name 'KPH' to stand for the
// composite SI unit 'km/hr', it can be done by creating a UnitName, and
// mapping it to the UnitMap lists.
// <note role=tip> The UnitMap::putUser can also be used without creating a UnitName
// first
// </note>
// <srcblock>
// UnitName myKPH( "KPH", UnitVal(3.6,"km/ks"));    // note ks = kilosecond
// UnitMap::putUser(myKPH);
// </srcblock>
//
//  <h3> Constructing a tagged unit definition </h3>
// The following constructors are available:
// <ol>
//   <li> UnitName()            create unnamed value 1.
//   <li> UnitName(const UnitName&) copy constructor
//   <li> UnitName("tag", UnitVal, "full name")
// </ol>
//
// An assignment (copy semantics) is available.
//
//
//  <h3> Obtaining information about tagged unit </h3>
// The following information can be obatined from a UnitName:
// <ol>
//   <li> UnitVal getVal() const    will return the unit definition value
//   <li> String  getName() const   will return the unit name
// </ol>
//
//
// </synopsis>
//
// <example>
// To obtain the definition of a Jy, you could:
// <srcblock>
// // Define a UnitVal unit definition
// UnitVal mydef;
// // And fill it with the appropiate definition
// mydef = (UnitMap::getUnit("Jy"))->getVal();
// </srcblock>
// </example>
//
// # // <motivation>
// # // </motivation>
 
class UnitName {
  // # friends
  //  Output the unit tag, description and its definition
  friend ostream &operator<<(ostream &os, const UnitName &name);
 
 public:
  // # Constructors
  //  Default constructor
  UnitName();
 
  // Copy constructor
  UnitName(const UnitName &other);
 
  // Construct from different parts
  // <group>
  UnitName(const String &nameTag, const UnitVal &kind, const String &fullName = String());
  UnitName(const Unit &unit, const String &fullName = String());
  // </group>
 
  // Destructor
  ~UnitName();
 
  // # Operators
  //  Assigment (copy semantics)
  UnitName &operator=(const UnitName &other);
 
  // # General member functions
  //  Get definition value of the unit
  const UnitVal &getVal() const { return basicKind; }
 
  // Get the name tag of the defined unit
  const String &getName() const { return basicTag; }
 
  // Get the full name of the defined unit
  const String &getFullName() const { return basicName; }
 
 private:
  // # Data members
  //  Value of defined unit
  UnitVal basicKind;
 
  // Name tag of unit
  String basicTag;
 
  // Full name and description of unit
  String basicName;
};
 
// # Inline Implementations
 
}  // namespace casacore
 
#endif