Direction.h

// -*- C++ -*-
//
// Direction.h is a part of ThePEG - Toolkit for HEP Event Generation
// Copyright (C) 1999-2019 Leif Lonnblad
//
// ThePEG is licenced under version 3 of the GPL, see COPYING for details.
// Please respect the MCnet academic guidelines, see GUIDELINES for details.
//
#ifndef ThePEG_Direction_H
#define ThePEG_Direction_H
// This is the declaration of the Direction class.
 
#include "ThePEG/Config/ThePEG.h"
#include "Direction.xh"
 
namespace ThePEG {
 
template <int I>
class Direction {
 
public:
 
  enum Dir { Neg = -1, 
             Negative = -1, 
             Undefined = 0, 
             Pos = 1, 
             Positive = 1 
  };
 
public:
 
  Direction(Dir newDirection)
    
  {
    if ( theDirection != Undefined ) throw MultipleDirectionException(I);
    if ( newDirection == Positive ) theDirection = Positive;
    else if ( newDirection == Negative ) theDirection = Negative;
    else throw UndefinedDirectionException(I);
  }
 
  Direction(double rnd)
  {
    if ( theDirection != Undefined ) throw MultipleDirectionException(I);
    theDirection = rnd > 0 ? Positive : Negative;
  }
 
  Direction(bool p)
  {
    if ( theDirection != Undefined ) throw MultipleDirectionException(I);
    theDirection = p ? Positive : Negative;
  }
 
  ~Direction() { theDirection = Undefined; }
 
public:
 
  static void set(Dir newDirection) {
    if ( newDirection == Positive ) theDirection = Positive;
    else if ( newDirection == Negative ) theDirection = Negative;
    else throw UndefinedDirectionException(I);
  }
 
  static void reverse() {
    theDirection = pos() ? Negative : Positive;
  }
 
  static bool pos() {
    return dir() == Positive;
  }
 
  static bool neg() {
    return dir() == Negative;
  }
 
  static Dir dir() {
    if ( theDirection == Undefined ) throw UndefinedDirectionException(I);
    return theDirection;
  }
 
private:
 
  static Dir theDirection;
 
private:
 
  Direction();
  Direction(const Direction &);
  Direction & operator=(const Direction &) = delete;
 
};
 
template<int I>
typename Direction<I>::Dir Direction<I>::theDirection = Direction<I>::Undefined;
 
}
 
#endif /* ThePEG_Direction_H */