Endless loop in QuickSort

Original Reporter info from Mantis: Chuck

• Reporter name: Chuck Norris

Description:

On a customer*s PC I could see that the QuickSort implementation in Classes.pas led to an endless loop. A Delphi like implementation solved the issue.

{code}
Procedure QuickSort(aList: TJSValueDynArray; L, R : Longint;
                    const Compare: TListSortCompareFunc);
var
  I, J: Longint;
  P, T: JSValue;
begin
  if L < R then
  begin
    repeat
      if (R - L) = 1 then
      begin
        if Compare(aList[L], aList[R]) > 0 then
        begin
          T := aList[L];
          aList[L] := aList[R];
          aList[R] := T;
        end;
        break;
      end;
      I := L;
      J := R;
      P := aList[(L + R) shr 1];
      repeat
        while Compare(aList[I], P) < 0 do
          Inc(I);
        while Compare(aList[J], P) > 0 do
          Dec(J);
        if I <= J then
        begin
          if I <> J then
          begin
            T := aList[I];
            aList[I] := aList[J];
            aList[J] := T;
          end;
          Inc(I);
          Dec(J);
        end;
      until I > J;
      if (J - L) > (R - I) then
      begin
        if I < R then
          QuickSort(aList, I, R, Compare);
        R := J;
      end
      else
      begin
        if L < J then
          QuickSort(aList, L, J, Compare);
        L := I;
      end;
    until L >= R;
  end;
end;
{code}

Mantis conversion info:

• Mantis ID: 38871
• Build: 2.0
• Fixed in version: trunk
• Fixed in revision: 1185.