GetUserSizeInKBFromBuffer

function TATABufferInterpreter.GetUserSizeInKBFromBuffer: UInt64;
const
  UserSizeStart = 100;
  UserSizeEnd = 103;
var
  CurrentWord: Integer;
begin
  result := 0;
  for CurrentWord := UserSizeStart to UserSizeEnd do
  begin
    result :=
      result +
      BufferInterpreting[CurrentWord * 2] shl
        (((CurrentWord - UserSizeStart) * 2) * 8) +
      BufferInterpreting[CurrentWord * 2 + 1]  shl
        ((((CurrentWord - UserSizeStart) * 2) + 1) * 8);
  end;
  result := result div 2;
end;