cube__number_of_flagged_bits Function

   pure function cube__number_of_flagged_bits(self) result(ret)
      implicit none
      class(cube_t), intent(in) :: self
      integer :: ret

      integer :: i
      integer :: partial_sum(0:BMP_SIZE-1)

      if (.not. self%is_switched_to_bmp) then
         ret = popcnt(self%ascii%a(0)) + popcnt(self%ascii%a(1))
         return
      end if

      ret = 0
      do concurrent (i = 0:BMP_SIZE-1)
         partial_sum(i) = popcnt(self%bmp%b(i))
      end do

      ret = sum(partial_sum)

      if (allocated(self%sps)) then
         do i = 1, size(self%sps)
            ret = ret + width_of_segment(self%sps(i))
         end do
      end if

   end function cube__number_of_flagged_bits