MCEpoch.h

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// # MCEpoch.h: MEpoch conversion routines
// # Copyright (C) 1995,1996,1997,1998,1999,2002
// # 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 MEASURES_MCEPOCH_H
#define MEASURES_MCEPOCH_H
 
// # Includes
#include <casacore/casa/aips.h>
#include <casacore/measures/Measures/MeasBase.h>
#include <casacore/measures/Measures/MeasRef.h>
#include <casacore/measures/Measures/MCBase.h>
#include <casacore/measures/Measures/MConvertBase.h>
#include <casacore/measures/Measures/MEpoch.h>
 
namespace casacore {  // # NAMESPACE CASACORE - BEGIN
 
// # Forward Declarations
class MCEpoch;
class Nutation;
class String;
 
// # Typedefs
 
// <summary> MEpoch conversion routines </summary>
 
// <use visibility=local>
 
// <reviewed reviewer="UNKNOWN" date="before2004/08/25" tests="tMeasure" demos="">
// </reviewed>
 
// <prerequisite>
//   <li> <linkto class=Measure>Measure</linkto> class
//   <li> <linkto class=MCBase>MCBase</linkto> base class
//   <li> <linkto class=MConvertBase>overall conversion</linkto>  class
// </prerequisite>
//
// <etymology>
// Measure, Convert and Epoch
// </etymology>
//
// <synopsis>
// Contains state machinery and caching for actual conversions
// </synopsis>
//
// <example>
// Convert (with all steps explicit) a UTC to an IAT time.
// <srcblock>
//  #include <casacore/measures/Measures.h>
//  #include <casacore/measures/Measures/MEpoch.h>
//  #include <casacore/measures/Measures/MCEpoch.h>
//  cout << "TAI for UTC = MJD(50237.29): " <<
//      MEpoch::Convert(MEpoch(MVEpoch(Quantity(50237.29, "d")),
//                         MEpoch::Ref(MEpoch::UTC)),
//                      MEpoch::Ref(MEpoch::TAI))() <<
//      endl;
// </srcblock>
// </example>
//
// <motivation>
// </motivation>
//
// <todo asof="1998/09/21">
//  <li> Nothing I know
// </todo>
 
class MCEpoch : public MCBase {
 public:
  // # Friends
  friend class MeasConvert<MEpoch>;
 
  // # Constructors
  //  Default constructor
  MCEpoch();
 
  // # Destructor
  ~MCEpoch();
 
  // # Member functions
  //  Show the state of the conversion engine (mainly for debugging purposes)
  static String showState();
 
 private:
  // # Enumerations
  //  The list of actual routines provided.
  //  <note role=warning> Each <src>AA_BB</src> in the list points to routine
  //  that can be used in the FromTo list in the getConvert routine.
  //  In addition the type to which each is converted should be in the
  //  ToRef array, again in the proper order. </note>
  enum Routes {
    LAST_GAST,
    GAST_LAST,
    LMST_GMST1,
    GMST1_LMST,
    GMST1_UT1,
    UT1_GMST1,
    GAST_UT1,
    UT1_GAST,
    UT1_UTC,
    UTC_UT1,
    UT1_UT2,
    UT2_UT1,
    UTC_TAI,
    TAI_UTC,
    TAI_TDT,
    TDT_TAI,
    TDT_TDB,
    TDB_TDT,
    TDT_TCG,
    TCG_TDT,
    TDB_TCB,
    TCB_TDB,
    N_Routes,
    RAZING
  };
 
  // # Typedefs
 
  // # Operators
 
  // # General Member Functions
 
  // # Enumerations
 
  // # Cached Data
  Nutation *NUTATFROM;
  Nutation *NUTATTO;
 
  // # State machine data
  //  Transition list
  static uInt ToRef_p[N_Routes][3];
  // Transition matrix
  static uInt FromTo_p[MEpoch::N_Types][MEpoch::N_Types];
  // Object to ensure safe multi-threaded lazy single initialization
  static std::once_flag theirInitOnceFlag;
 
  // # Constructors
  //  Copy constructor (not implemented)
  MCEpoch(const MCEpoch &other);
  // Assignment (not implemented)
  MCEpoch &operator=(const MCEpoch &other);
 
  // # Member functions
 
  // Create conversion function pointer
  virtual void getConvert(MConvertBase &mc, const MRBase &inref, const MRBase &outref);
 
  // Create help structures for Measure conversion routines
  virtual void initConvert(uInt which, MConvertBase &mc);
 
  // Delete the pointers used in the MeasConvert help structure cache
  virtual void clearConvert();
 
  // Routine to convert time from one reference frame to another
  virtual void doConvert(MeasValue &in, MRBase &inref, MRBase &outref, const MConvertBase &mc);
  // Conversion routine to cater for inheritance question
  void doConvert(MVEpoch &in, MRBase &inref, MRBase &outref, const MConvertBase &mc);
 
 private:
  // Fill the global state. Called using theirInitOnce.
  static void doFillState();
};
 
}  // namespace casacore
 
#endif