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// G4LineSection
//
// Class description:
//
// A utility class that calculates the distance of a point from a 
// line section.

// Author: John Apostolakis (CERN), 1999
// --------------------------------------------------------------------

#ifndef G4LineSection_hh
#define G4LineSection_hh

#include "G4Types.hh" 
#include "G4ThreeVector.hh"

/**
 * @brief G4LineSection is a utility class that calculates the distance
 * of a point from a line section.
 */

class G4LineSection
{
  public:

    /**
     * Constructor for G4LineSection.
     *  @param[in] PntA Coordinates of point A defining the line.
     *  @param[in] PntB Coordinates of point B defining the line.
     */
    G4LineSection( const G4ThreeVector& PntA,
                   const G4ThreeVector& PntB );

    /**
     * Default Destructor.
     */
    ~G4LineSection() = default;

    /**
     * Returns the distance of point 'OtherPnt' from the line.
     */
    G4double Dist( const G4ThreeVector& OtherPnt ) const;

    /**
     * Returns the distance squared.
     */
    inline G4double GetABdistanceSq() const;

    /**
     * Defines line and returns the distance of point 'OtherPnt' from it.
     */
    inline static G4double Distline( const G4ThreeVector& OtherPnt, 
                                     const G4ThreeVector& LinePntA, 
                                     const G4ThreeVector& LinePntB );
  private:

    G4ThreeVector EndpointA;
    G4ThreeVector VecAtoB;
    G4double fABdistanceSq = 0.0;
};

// Inline methods implementations

inline
G4double G4LineSection::GetABdistanceSq() const
{
  return fABdistanceSq;
}

inline
G4double G4LineSection::Distline( const G4ThreeVector& OtherPnt, 
                                  const G4ThreeVector& LinePntA, 
                                  const G4ThreeVector& LinePntB )
{
  G4LineSection LineAB( LinePntA, LinePntB );  // Line from A to B
  return LineAB.Dist( OtherPnt );
}

#endif