// Copyright (c) 1998-1999 Matra Datavision
// Copyright (c) 1999-2014 OPEN CASCADE SAS
//
// This file is part of Open CASCADE Technology software library.
//
// This library is free software; you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License version 2.1 as published
// by the Free Software Foundation, with special exception defined in the file
// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
// distribution for complete text of the license and disclaimer of any warranty.
//
// Alternatively, this file may be used under the terms of Open CASCADE
// commercial license or contractual agreement.

// SortTools_ShellSort.gxx
// cree le 04/11/91 par ASI
// Reference : Software Conponents with ADA, Grady Booch.

void SortTools_ShellSort::Sort(Array& TheArray, 
				      const Comparator& Comp) 
{

  Item    TempItem;
  Standard_Integer Outer;
  Standard_Integer Inner;
  Standard_Integer Inc = 1;

  for(;;) {
    if((9 * Inc) + 4 >= TheArray.Upper() - TheArray.Lower() + 1) break;
    Inc = (Inc * 3) + 1;
  }
  for(;;) {
    Outer = TheArray.Lower() + Inc;
    for(;;) {
      TempItem = TheArray(Outer);
      Inner = Outer;
      while (Comp.IsLower(TempItem, TheArray(Inner - Inc))) {
	TheArray(Inner) = TheArray(Inner - Inc);
	Inner = Inner - Inc;
	if(Inner - Inc < TheArray.Lower()) break;
      }
      TheArray(Inner) = TempItem;
      if(Outer + Inc > TheArray.Upper()) break;
      Outer = Outer + Inc;
    }
    if(Inc == 1) break;
    Inc = (Inc - 1) / 3;
  }
}