ULONG
CdShortNameDirentOffset(
  IN  PIRP_CONTEXT IrpContext,
  IN  PUNICODE_STRING Name
  );

Routine Description:

    This routine is called to examine a name to see if the dirent offset string is contained.
    This consists of a tilde character followed by the offset represented as a hexadecimal
    characters.  We don't do any other checks to see if this is a short name.  We
    catch that later outside this routine.

Arguments:

    Name - This is the CdName to examine.

Return Value:

    ULONG - MAXULONG if there is no valid dirent offset string embedded, otherwise the
        convert the value to numeric form.