//*CMZ :  2.23/07 27/10/99  10.47.27  by  Fons Rademakers
//*CMZ :  2.20/00 12/11/98  17.11.54  by  Fons Rademakers
//*CMZ :  2.00/13 20/10/98  12.33.43  by  Fons Rademakers
//*CMZ :  2.00/11 17/08/98  15.18.35  by  Rene Brun
//*CMZ :  1.03/04 29/09/97  19.08.23  by  Fons Rademakers
//*-- Author :    Fons Rademakers   10/08/95

//*KEEP,CopyRight,T=C.
/*************************************************************************
 * Copyright(c) 1995-1999, The ROOT System, All rights reserved.         *
 * Authors: Rene Brun and Fons Rademakers.                               *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/AA_LICENSE.                      *
 * For the list of contributors see $ROOTSYS/AA_CREDITS.                 *
 *************************************************************************/
//*KEND.

//////////////////////////////////////////////////////////////////////////
//                                                                      //
// THashList                                                            //
//                                                                      //
// THashList implements a hybrid collection class consisting of a       //
// hash table and a list to store TObject's. The hash table is used for //
// quick access and lookup of objects while the list allows the objects //
// to be ordered. The hash value is calculated using the value returned //
// by the TObject's Hash() function. Each class inheriting from TObject //
// can override Hash() as it sees fit.                                  //
//
/*

*/
//
//                                                                      //
//////////////////////////////////////////////////////////////////////////

//*KEEP,THashList.
#include "THashList.h"
//*KEEP,THashTable.
#include "THashTable.h"
//*KEND.


ClassImp(THashList)

//______________________________________________________________________________
 THashList::THashList(Int_t capacity, Int_t rehash)
{
   // Create a THashList object. Capacity is the initial hashtable capacity
   // (i.e. number of slots), by default kInitHashTableCapacity = 17, and
   // rehash is the value at which a rehash will be triggered. I.e. when the
   // average size of the linked lists at a slot becomes longer than rehash
   // then the hashtable will be resized and refilled to reduce the collision
   // rate to about 1. The higher the collision rate, i.e. the longer the
   // linked lists, the longer lookup will take. If rehash=0 the table will
   // NOT automatically be rehashed. Use Rehash() for manual rehashing.

   fTable = new THashTable(capacity, rehash);
}

//______________________________________________________________________________
 THashList::THashList(TObject *parent, Int_t capacity, Int_t rehash)
           : TList(parent)
{
   // Create a THashList object. Capacity is the initial hashtable capacity
   // (i.e. number of slots), by default kInitHashTableCapacity = 17, and
   // rehash is the value at which a rehash will be triggered. I.e. when the
   // average size of the linked lists at a slot becomes longer than rehash
   // then the hashtable will be resized and refilled to reduce the collision
   // rate to about 1. The higher the collision rate, i.e. the longer the
   // linked lists, the longer lookup will take. If rehash=0 the table will
   // NOT automatically be rehashed. Use Rehash() for manual rehashing.

   fTable = new THashTable(capacity, rehash);
}

//______________________________________________________________________________
 THashList::~THashList()
{
   // Delete a hashlist. All objects will be removed from the list before the
   // list will be deleted.

   Clear();
   SafeDelete(fTable);
}

//______________________________________________________________________________
 void THashList::AddFirst(TObject *obj)
{
   // Add object at the beginning of the list.

   TList::AddFirst(obj);
   fTable->Add(obj);
}

//______________________________________________________________________________
 void THashList::AddFirst(TObject *obj, Option_t *opt)
{
   // Add object at the beginning of the list and also store option.
   // Storing an option is useful when one wants to change the behaviour
   // of an object a little without having to create a complete new
   // copy of the object. This feature is used, for example, by the Draw()
   // method. It allows the same object to be drawn in different ways.

   TList::AddFirst(obj, opt);
   fTable->Add(obj);
}

//______________________________________________________________________________
 void THashList::AddLast(TObject *obj)
{
   // Add object at the end of the list.

   TList::AddLast(obj);
   fTable->Add(obj);
}

//______________________________________________________________________________
 void THashList::AddLast(TObject *obj, Option_t *opt)
{
   // Add object at the end of the list and also store option.
   // Storing an option is useful when one wants to change the behaviour
   // of an object a little without having to create a complete new
   // copy of the object. This feature is used, for example, by the Draw()
   // method. It allows the same object to be drawn in different ways.

   TList::AddLast(obj, opt);
   fTable->Add(obj);
}

//______________________________________________________________________________
 void THashList::AddBefore(TObject *before, TObject *obj)
{
   // Insert object before object before in the list.

   TList::AddBefore(before, obj);
   fTable->Add(obj);
}

//______________________________________________________________________________
 void THashList::AddBefore(TObjLink *before, TObject *obj)
{
   // Insert object before object before in the list.

   TList::AddBefore(before, obj);
   fTable->Add(obj);
}

//______________________________________________________________________________
 void THashList::AddAfter(TObject *after, TObject *obj)
{
   // Insert object after object after in the list.

   TList::AddAfter(after, obj);
   fTable->Add(obj);
}

//______________________________________________________________________________
 void THashList::AddAfter(TObjLink *after, TObject *obj)
{
   // Insert object after object after in the list.

   TList::AddAfter(after, obj);
   fTable->Add(obj);
}

//______________________________________________________________________________
 void THashList::AddAt(TObject *obj, Int_t idx)
{
   // Insert object at location idx in the list.

   TList::AddAt(obj, idx);
   fTable->Add(obj);
}

//______________________________________________________________________________
 Float_t THashList::AverageCollisions() const
{
   // Return the average collision rate. The higher the number the longer
   // the linked lists in the hashtable, the slower the lookup. If the number
   // is high, or lookup noticeably too slow, perfrom a Rehash().

   return fTable->AverageCollisions();
}

//______________________________________________________________________________
 void THashList::Clear(Option_t *option)
{
   // Remove all objects from the list. Does not delete the objects.

   TList::Clear(option);
   fTable->Clear("nodelete");  // any kCanDelete objects have already been deleted
}

//______________________________________________________________________________
 void THashList::Delete(Option_t *option)
{
   // Remove all objects from the list AND delete all heap based objects.

   TList::Delete(option);      // this deletes the objects
   fTable->Clear("nodelete");  // all objects have already been deleted
}

//______________________________________________________________________________
 TObject *THashList::FindObject(const Text_t *name) const
{
   // Find object using its name. Uses the hash value returned by the
   // TString::Hash() after converting name to a TString.

   return fTable->FindObject(name);
}

//______________________________________________________________________________
 TObject *THashList::FindObject(TObject *obj) const
{
   // Find object using its hash value (returned by its Hash() member).

   return fTable->FindObject(obj);
}

//______________________________________________________________________________
 void THashList::Rehash(Int_t newCapacity)
{
   // Rehash the hashlist. If the collision rate becomes too high (i.e.
   // the average size of the linked lists become too long) then lookup
   // efficiency decreases since relatively long lists have to be searched
   // every time. To improve performance rehash the hashtable. This resizes
   // the table to newCapacity slots and refills the table. Use
   // AverageCollisions() to check if you need to rehash.

   fTable->Rehash(newCapacity);
}

//______________________________________________________________________________
 TObject *THashList::Remove(TObject *obj)
{
   // Remove object from the list.

   if (!obj || !fTable->FindObject(obj)) return 0;

   TList::Remove(obj);
   return fTable->Remove(obj);
}

//______________________________________________________________________________
 TObject *THashList::Remove(TObjLink *lnk)
{
   // Remove object via its objlink from the list.

   if (!lnk) return 0;

   TObject *obj = lnk->GetObject();

   TList::Remove(lnk);
   return fTable->Remove(obj);
}