extend_unique_string Subroutine

  subroutine extend_unique_string(nonunique, unique)
    ! Add entries from nonunique to the next blank of unique unless already present
    character(len=*), dimension(:), intent(in) :: nonunique
    character(len=*), dimension(:), intent(inout) :: unique
    logical add
    integer i, ii, iv
    iv = 1
    ! Shift iv counter to allow for already present unique entries
    do ii = 1, size(unique)
      if (trim(unique(ii)) == "") then
        exit
      end if
      iv = iv + 1
    end do
    ! Add nonunique to unique unless already in unique
    do i = 1, size(nonunique)
      add = .True.
      do ii = 1, size(unique)
        if (trim(nonunique(i)) == trim(unique(ii))) then
          add = .False.
          exit
        else if (trim(unique(ii)) == "") then
          exit
        end if
      end do
      if (add) then
        if (iv > size(unique)) then
          call log_error('extend_unique_string', &
            "Trying to extend unique array autside size.", i1=iv, int=size(unique))
        end if
        unique(iv) = nonunique(i)
        iv = iv + 1
      end if
    end do
  end subroutine extend_unique_string