// File:	MAT_TList.gxx
// Created:	Wed Jun 24 12:47:46 1992
// Author:	Gilles DEBARBOUILLE
//		<gde@phobox>


//=======================================================================
//function : MAT_TList
//purpose  : 
//=======================================================================

MAT_TList::MAT_TList()
{
  thecurrentindex  = 0;
  thenumberofitems = 0;
}

//=======================================================================
//function : First
//purpose  : 
//=======================================================================

void MAT_TList::First()
{
  thecurrentnode = thefirstnode;
  thecurrentindex = 1;
}

//=======================================================================
//function : Last
//purpose  : 
//=======================================================================

void MAT_TList::Last()
{
  thecurrentnode = thelastnode;
  thecurrentindex = thenumberofitems;
}

//=======================================================================
//function : Init
//purpose  : 
//=======================================================================

void MAT_TList::Init(const Item& anitem)
{
  First();
  while(More())
    {
      if(anitem == thecurrentnode->GetItem()) break;
      Next();
    }
}

//=======================================================================
//function : Next
//purpose  : 
//=======================================================================

void MAT_TList::Next()
{
  if(!IsEmpty())
    {
      thecurrentnode = thecurrentnode->Next();
      thecurrentindex = (thecurrentindex % thenumberofitems) + 1;
    }
}

//=======================================================================
//function : Previous
//purpose  : 
//=======================================================================

void MAT_TList::Previous()
{
  if(!IsEmpty())
    {
      thecurrentnode = thecurrentnode->Previous();
      thecurrentindex = ((thecurrentindex+thenumberofitems-2)%thenumberofitems)+1;
    }
}

//=======================================================================
//function : More
//purpose  : 
//=======================================================================

Standard_Boolean MAT_TList::More() const
{
  return (!thecurrentnode.IsNull());
}

//=======================================================================
//function : Current
//purpose  : 
//=======================================================================

Item MAT_TList::Current() const
{
  return thecurrentnode->GetItem();
}

//=======================================================================
//function : Current
//purpose  : 
//=======================================================================

void MAT_TList::Current(const Item& anitem) const
{
  thecurrentnode->SetItem(anitem);
}

//=======================================================================
//function : FirstItem
//purpose  : 
//=======================================================================

Item MAT_TList::FirstItem() const
{
  return thefirstnode->GetItem();
}

//=======================================================================
//function : LastItem
//purpose  : 
//=======================================================================

Item MAT_TList::LastItem() const
{
  return thelastnode->GetItem();
}

//=======================================================================
//function : PreviousItem
//purpose  : 
//=======================================================================

Item MAT_TList::PreviousItem() const
{
  return thecurrentnode->Previous()->GetItem();
}

//=======================================================================
//function : NextItem
//purpose  : 
//=======================================================================

Item MAT_TList::NextItem() const
{
  return thecurrentnode->Next()->GetItem();
}

//=======================================================================
//function : Brackets
//purpose  : 
//=======================================================================

Item MAT_TList::Brackets (const Standard_Integer anindex)
{
  if(thecurrentindex > anindex)
    {
      while(thecurrentindex != anindex)
	{
	  thecurrentindex--;
	  thecurrentnode = thecurrentnode->Previous();
	}
    }
  else if(thecurrentindex < anindex)
    {
      while(thecurrentindex != anindex)
	{
	  thecurrentindex++;
	  thecurrentnode = thecurrentnode->Next();
	}
    }
  return thecurrentnode->GetItem();
}

//=======================================================================
//function : Unlink
//purpose  : 
//=======================================================================

void MAT_TList::Unlink()
{
  Standard_Boolean previousisnull = thecurrentnode->Previous().IsNull();
  Standard_Boolean nextisnull = thecurrentnode->Next().IsNull();

  if(thecurrentindex)
    {
      if(!nextisnull && !previousisnull)
	{
	  thecurrentnode->Next()->Previous(thecurrentnode->Previous());
	  thecurrentnode->Previous()->Next(thecurrentnode->Next());
	}

      if(thecurrentindex == 1)
	{
	  thefirstnode = thecurrentnode->Next();
	}
      else if(thecurrentindex == thenumberofitems)
	{
	  thelastnode = thecurrentnode->Previous();
	}
    }
  thenumberofitems--;
  thecurrentindex--;
}

//=======================================================================
//function : LinkBefore
//purpose  : 
//=======================================================================

void MAT_TList::LinkBefore(const Item& anitem)
{
  thenumberofitems++;
  if(thecurrentindex)thecurrentindex++;

  Handle(MAT_TListNode) previous;

  Handle(MAT_TListNode) node = new MAT_TListNode(anitem);

  if(!(thecurrentnode->Previous()).IsNull())
    {
      previous = thecurrentnode->Previous();
      previous->Next(node);
      node->Previous(previous);
    }

  if(thecurrentindex == 2)
    {
      thefirstnode = node;
    }

  thecurrentnode->Previous(node);
  node->Next(thecurrentnode);
}

//=======================================================================
//function : LinkAfter
//purpose  : 
//=======================================================================

void MAT_TList::LinkAfter(const Item& anitem)
{
  thenumberofitems++;
  Handle(MAT_TListNode) next;

  Handle(MAT_TListNode) node = new MAT_TListNode(anitem);

  if(!(thecurrentnode->Next()).IsNull())
    {
      next = thecurrentnode->Next();
      next->Previous(node);
      node->Next(next);
    }

  if(thecurrentindex+1 ==thenumberofitems)
    {
      thelastnode = node;
    }

  thecurrentnode->Next(node);
  node->Previous(thecurrentnode);
}

//=======================================================================
//function : FrontAdd
//purpose  : 
//=======================================================================

void MAT_TList::FrontAdd(const Item& anitem)
{
  thenumberofitems++;
  if(thecurrentindex)thecurrentindex++;

  Handle(MAT_TListNode) node = new MAT_TListNode(anitem);

  if(!thefirstnode.IsNull())
    {
      thefirstnode->Previous(node);
      node->Next(thefirstnode);
    }
  else
    {
      thelastnode = node;
    }

  thefirstnode = node;
}

//=======================================================================
//function : BackAdd
//purpose  : 
//=======================================================================

void MAT_TList::BackAdd(const Item& anitem)
{
  thenumberofitems++;
  Handle(MAT_TListNode) node = new MAT_TListNode(anitem);

  if(!thelastnode.IsNull())
    {
      thelastnode->Next(node);
      node->Previous(thelastnode);
    }
  else
    {
      thefirstnode = node;
    }

  thelastnode = node;
}

//=======================================================================
//function : Permute
//purpose  : 
//=======================================================================

void MAT_TList::Permute()
{
  Handle(MAT_TListNode) previous = thecurrentnode->Previous();
  Handle(MAT_TListNode) current  = thecurrentnode;
  Handle(MAT_TListNode) next     = thecurrentnode->Next();
  Handle(MAT_TListNode) nextnext = next->Next();
  Handle(MAT_TListNode) null;

  if(!previous.IsNull())
    {
      previous->Next(next);
      next->Previous(previous);
    }
  else
    {
      next->Previous(null);
    }
  next->Next(current);
  current->Previous(next);
  if(!nextnext.IsNull())
    {
      current->Next(nextnext);
      nextnext->Previous(current);
    }
  else
    {
      current->Next(null);
    }
  if(thefirstnode == current) thefirstnode = next;
  if(thelastnode  == next) thelastnode = current;
  thecurrentindex++;
}

//=======================================================================
//function : Loop
//purpose  : 
//=======================================================================

void MAT_TList::Loop() const
{
  thelastnode->Next(thefirstnode);
  thefirstnode->Previous(thelastnode);
}

//=======================================================================
//function : Dump
//purpose  : 
//=======================================================================

void MAT_TList::Dump(const Standard_Integer ashift,
		     const Standard_Integer alevel)
{
  for(First(); More(); Next()) Current()->Dump(ashift,alevel);
}