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-rw-r--r--lib/tv/src/tv_pg_gridfcns.erl32
1 files changed, 25 insertions, 7 deletions
diff --git a/lib/tv/src/tv_pg_gridfcns.erl b/lib/tv/src/tv_pg_gridfcns.erl
index ab88e2864f..3d23c8a69f 100644
--- a/lib/tv/src/tv_pg_gridfcns.erl
+++ b/lib/tv/src/tv_pg_gridfcns.erl
@@ -205,8 +205,8 @@ resize_grid(NewWidth, NewHeight, ProcVars) ->
check_nof_cols(ColsShown, (NofColsShown - NofCols), ColFrameIds, ColIds,
RowIds, NofRows, RowHeight, FgColor, BgColor ),
- clear_fields(lists:nthtail(NofColsShown, NewColIds),
- lists:nthtail(NofRowsShown, NewRowIds)),
+ clear_fields(safe_nthtail(NofColsShown, NewColIds),
+ safe_nthtail(NofRowsShown, NewRowIds)),
RowsToUpdate = lists:sublist(NewRowIds, NofRowsShown),
@@ -279,7 +279,7 @@ resize_grid_column(RealCol, VirtualCol, Xdiff, ProcVars) ->
% Update the ColWidths list.
TempColWidths = lists:sublist(ColWidths, VirtualCol - 1) ++
- [NewWidthOfCol | lists:nthtail(VirtualCol, ColWidths)],
+ [NewWidthOfCol | safe_nthtail(VirtualCol, ColWidths)],
% Check the other columns, whether a new column has to be created.
ColsShown = compute_cols_shown(FirstColShown, TempColWidths, GridWidth,
@@ -455,8 +455,8 @@ scroll_grid_horizontally(NewFirstColShown, ProcVars) ->
refresh_visible_rows(RowsToUpdate, NewFirstColShown, NofColsShown, RowDataList, ListAsStr),
% Clear fields currently not visible.
- clear_fields(lists:nthtail(NofColsShown, NewColIds),
- lists:nthtail(NofRowsShown, NewRowIds)),
+ clear_fields(safe_nthtail(NofColsShown, NewColIds),
+ safe_nthtail(NofRowsShown, NewRowIds)),
NewGridP = GridP#grid_params{nof_cols = NewNofCols,
@@ -1565,7 +1565,7 @@ update_col_widths(ColsShown, ColWidths, FirstColShown, DefaultColWidth) ->
if
NecessaryNofVirtualCols > NofVirtualCols ->
TailNo = NofVirtualCols - FirstColShown + 1, % Always >= 0 !!!
- NewColWidths ++ lists:nthtail(TailNo, ColsShown);
+ NewColWidths ++ safe_nthtail(TailNo, ColsShown);
true ->
NewColWidths
end.
@@ -1653,7 +1653,7 @@ compute_cols_shown(FirstColShown, ColWidths, GridWidth, _NofCols, DefaultColWidt
ColWidthsLength < FirstColShown ->
[];
true ->
- lists:nthtail(FirstColShown - 1, ColWidths)
+ safe_nthtail(FirstColShown - 1, ColWidths)
end,
compute_cols_shown(UsedColWidths, GridWidth, DefaultColWidth).
@@ -1894,3 +1894,21 @@ extract_ids_for_one_row(N, [ColIds | Tail]) ->
%%%---------------------------------------------------------------------
%%% END of functions used to create the grid.
%%%---------------------------------------------------------------------
+
+
+%%======================================================================
+%% Function:
+%%
+%% Return Value:
+%%
+%% Description:
+%%
+%% Parameters:
+%%======================================================================
+
+
+safe_nthtail(_, []) -> [];
+safe_nthtail(1, [_|T]) -> T;
+safe_nthtail(N, [_|T]) when N > 1 ->
+ safe_nthtail(N - 1, T);
+safe_nthtail(0, L) when is_list(L) -> L.