Inno Setup script sample part 3

compare.pas

function GetNumber(var temp: String): Integer;
var
  part: String;
  pos1: Integer;
begin
  if Length(temp) = 0 then
  begin
    Result := -1;
    Exit;
  end;
    pos1 := Pos('.', temp);
    if (pos1 = 0) then
    begin
      Result := StrToInt(temp);
    temp := '';
    end
    else
    begin
    part := Copy(temp, 1, pos1 - 1);
      temp := Copy(temp, pos1 + 1, Length(temp));
      Result := StrToInt(part);
    end;
end;
 
function CompareInner(var temp1, temp2: String): Integer;
var
  num1, num2: Integer;
begin
    num1 := GetNumber(temp1);
  num2 := GetNumber(temp2);
  if (num1 = -1) or (num2 = -1) then
  begin
    Result := 0;
    Exit;
  end;
      if (num1 > num2) then
      begin
        Result := 1;
      end
      else if (num1 < num2) then
      begin
        Result := -1;
      end
      else
      begin
        Result := CompareInner(temp1, temp2);
      end;
end;
 
function CompareVersion(str1, str2: String): Integer;
var
  temp1, temp2: String;
begin
    temp1 := str1;
    temp2 := str2;
    Result := CompareInner(temp1, temp2);
end;