// 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;
  }
}