//  SMESH SMDS : implementaion of Salome mesh data structure
//
//  Copyright (C) 2003  OPEN CASCADE, EADS/CCR, LIP6, CEA/DEN,
//  CEDRAT, EDF R&D, LEG, PRINCIPIA R&D, BUREAU VERITAS 
// 
//  This library is free software; you can redistribute it and/or 
//  modify it under the terms of the GNU Lesser General Public 
//  License as published by the Free Software Foundation; either 
//  version 2.1 of the License. 
// 
//  This library is distributed in the hope that it will be useful, 
//  but WITHOUT ANY WARRANTY; without even the implied warranty of 
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU 
//  Lesser General Public License for more details. 
// 
//  You should have received a copy of the GNU Lesser General Public 
//  License along with this library; if not, write to the Free Software 
//  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA 
// 
// See http://www.salome-platform.org/ or email : webmaster.salome@opencascade.com
//
//
//
//  File   : SMDS_MeshIDFactory.cxx
//  Author : Jean-Michel BOULCOURT
//  Module : SMESH


#include "SMDS_MeshIDFactory.hxx"

using namespace std;

//=======================================================================
//function : SMDS_MeshIDFactory
//purpose  : 
//=======================================================================

SMDS_MeshIDFactory::SMDS_MeshIDFactory():myMaxID(0)
{
}

int SMDS_MeshIDFactory::GetFreeID()
{
	if (myPoolOfID.empty()) return ++myMaxID;
	else
	{
                set<int>::iterator i = myPoolOfID.begin();
		int ID = *i;//myPoolOfID.top();
		myPoolOfID.erase( i );//myPoolOfID.pop();
		return ID;
	}
}

//=======================================================================
//function : ReleaseID
//purpose  : 
//=======================================================================
void SMDS_MeshIDFactory::ReleaseID(const int ID)
{
  if ( ID > 0 )
  {
    if ( ID < myMaxID )
    {
      myPoolOfID.insert(ID);
    }
    else if ( ID == myMaxID )
    {
      --myMaxID;
      if ( !myPoolOfID.empty() ) // assure that myMaxID is not in myPoolOfID
      {
        set<int>::iterator i = --myPoolOfID.end();
        while ( i != myPoolOfID.begin() && myMaxID == *i ) {
          --myMaxID; --i;
        }
        if ( myMaxID == *i )
          --myMaxID; // begin of myPoolOfID reached
        else
          ++i;
        myPoolOfID.erase( i, myPoolOfID.end() );
      }
    }
  }
}

void SMDS_MeshIDFactory::Clear()
{
  myMaxID = 0;
  myPoolOfID.clear();
}
