copy_line
copy_line(q_data_out, p, p_out,
copy_line(page->data, strchr(page->data, '\n'), first_line, line_size);
copy_line(pos, end, last_line, line_size);
copy_line(start_pos, end_pos, first_line, line_size);
copy_line(start_pos, end_pos, last_line, line_size);