ascii__add_character_range Subroutine

   pure subroutine ascii__add_character_range(self, min_cp, max_cp)
      implicit none
      class(ascii_t), intent(inout) :: self 
      integer(int32), intent(in) :: min_cp, max_cp

      integer :: ib, ie
      integer :: pb, pe
      integer :: i
      integer(int64) :: c1, c2

      if (min_cp > max_cp) return
      if (min_cp > ASCII_SIZE_BIT) return
      if (min_cp == max_cp) then
         call ascii__add_character_codepoint(self, min_cp)
         return
      end if

      ib = min_cp / bits_64
      ie = min(max_cp/bits_64, ASCII_SIZE-1)

      pb = mod(min_cp, bits_64)
      if (max_cp > ASCII_SIZE_BIT) then
         pe = 64
      else
         pe = mod(max_cp, bits_64)
      end if

      if (ib > ASCII_SIZE-1) return

      c1 = self%a(ib)
      c2 = self%a(ie)
      if (ib == ie) then
         self%a(ib) = ior(c1, shiftl( (ishft(1_8, pe-pb+1) -1), pb))
      else
         self%a(ib) = ior(c1, shiftl(-1_int64, pb))
         self%a(ie) = ior(c2, (ishft(1_int64, pe+1)-1))
      end if

   end subroutine ascii__add_character_range