Compare() declared const

[u/mrichter/AliRoot.git] / MUON / AliMUONTrackHit.cxx

/**************************************************************************
 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
 *                                                                        *
 * Author: The ALICE Off-line Project.                                    *
 * Contributors are mentioned in the code where appropriate.              *
 *                                                                        *
 * Permission to use, copy, modify and distribute this software and its   *
 * documentation strictly for non-commercial purposes is hereby granted   *
 * without fee, provided that the above copyright notice appears in all   *
 * copies and that both the copyright notice and this permission notice   *
 * appear in the supporting documentation. The authors make no claims     *
 * about the suitability of this software for any purpose. It is          *
 * provided "as is" without express or implied warranty.                  *
 **************************************************************************/

/*
$Log$
Revision 1.4  2000/07/18 16:04:06  gosset
AliMUONEventReconstructor package:
* a few minor modifications and more comments
* a few corrections
  * right sign for Z of raw clusters
  * right loop over chambers inside station
  * symmetrized covariance matrix for measurements (TrackChi2MCS)
  * right sign of charge in extrapolation (ExtrapToZ)
  * right zEndAbsorber for Branson correction below 3 degrees
* use of TVirtualFitter instead of TMinuit for AliMUONTrack::Fit
* no parameter for AliMUONTrack::Fit() but more fit parameters in Track object

Revision 1.3  2000/06/25 13:06:39  hristov
Inline functions moved from *.cxx to *.h files instead of forward declarations

Revision 1.2  2000/06/15 07:58:49  morsch
Code from MUON-dev joined

Revision 1.1.2.3  2000/06/12 10:11:45  morsch
Dummy copy constructor and assignment operator added

Revision 1.1.2.2  2000/06/09 12:58:05  gosset
Removed comment beginnings in Log sections of .cxx files
Suppressed most violations of coding rules

Revision 1.1.2.1  2000/06/07 14:44:53  gosset
Addition of files for track reconstruction in C++
*/

//__________________________________________________________________________
//
// Reconstructed track hit in ALICE dimuon spectrometer
//__________________________________________________________________________

#include "AliMUONTrackHit.h" 

#include "AliMUONHitForRec.h" 

ClassImp(AliMUONTrackHit) // Class implementation in ROOT context

  //__________________________________________________________________________
AliMUONTrackHit::AliMUONTrackHit(AliMUONHitForRec* Hit)
{
  // Constructor from the HitForRec pointed to by "Hit"
  fHitForRecPtr = Hit; // pointer to HitForRec
  // links from/to HitForRec
  if (Hit->GetNTrackHits() == 0) {
    fPrevTrackHitWithSameHitForRec = NULL;
    Hit->SetFirstTrackHitPtr(this);
  }
  else {
    fPrevTrackHitWithSameHitForRec = Hit->GetLastTrackHitPtr();
    fNextTrackHitWithSameHitForRec = NULL;
  }
  Hit->SetLastTrackHitPtr(this);
  fNextTrackHitWithSameHitForRec = NULL;
  Hit->SetNTrackHits(Hit->GetNTrackHits() + 1);
}

  //__________________________________________________________________________
AliMUONTrackHit::AliMUONTrackHit (const AliMUONTrackHit& MUONTrackHit)
{
// Dummy copy constructor
}

  //__________________________________________________________________________
AliMUONTrackHit & AliMUONTrackHit::operator=(const AliMUONTrackHit& MUONTrackHit)
{
// Dummy assignment operator
    return *this;
}


  //__________________________________________________________________________
AliMUONTrackHit::~AliMUONTrackHit()
{
  // Destructor
  // Update links between HitForRec's and TrackHit's
  // connected to the current TrackHit being removed.
  AliMUONHitForRec *hit = fHitForRecPtr; // pointer to HitForRec
  // remove current TrackHit in HitForRec links
  if (this == hit->GetFirstTrackHitPtr())
    hit->SetFirstTrackHitPtr(fNextTrackHitWithSameHitForRec); // if first
  if (this == hit->GetLastTrackHitPtr())
    hit->SetLastTrackHitPtr(fPrevTrackHitWithSameHitForRec); // if last
  hit->SetNTrackHits(hit->GetNTrackHits() - 1); // decrement NTrackHits of hit
  // update link to next TrackHit of previous TrackHit
  if (fPrevTrackHitWithSameHitForRec != NULL)
    fPrevTrackHitWithSameHitForRec->
      SetNextTrackHitWithSameHitForRec(fNextTrackHitWithSameHitForRec);
  // update link to previous TrackHit of next TrackHit
  if (fNextTrackHitWithSameHitForRec)
    fNextTrackHitWithSameHitForRec->
      SetPrevTrackHitWithSameHitForRec(fPrevTrackHitWithSameHitForRec);
  // to be checked thoroughly !!!!
  // with Root counter of AliMUONTrackHit objects,
  // with loop over all these links after the update
}

  //__________________________________________________________________________
Int_t AliMUONTrackHit::Compare(TObject* TrackHit)
{
  // "Compare" function to sort with increasing Z.
  // Returns -1 (0, +1) if Z of current TrackHit
  // is smaller than (equal to, larger than) Z of TrackHit
  if (fHitForRecPtr->GetZ() <
      ((AliMUONTrackHit*)TrackHit)->fHitForRecPtr->GetZ()) return(-1);
  else if (fHitForRecPtr->GetZ() ==
	   ((AliMUONTrackHit*)TrackHit)->fHitForRecPtr->GetZ()) return( 0);
  else return(+1);
}