[PATCH 2/2] comctl32/edit: Avoid division by zero in EDIT_EM_LineScroll_internal.

[Roman Pišl]

Signed-off-by: Roman Pišl <rpisl at seznam.cz>
---
 dlls/comctl32/edit.c       | 8 ++++++--
 dlls/comctl32/tests/edit.c | 4 ++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/dlls/comctl32/edit.c b/dlls/comctl32/edit.c
index b0c32445b0..4861fd7a9c 100644
--- a/dlls/comctl32/edit.c
+++ b/dlls/comctl32/edit.c
@@ -1579,8 +1579,12 @@ static BOOL EDIT_EM_LineScroll_internal(EDITSTATE *es, INT dx, INT dy)
 {
 	INT nyoff;
 	INT x_offset_in_pixels;
-	INT lines_per_page = (es->format_rect.bottom - es->format_rect.top) /
-			      es->line_height;
+	INT lines_per_page;
+
+	if (!es->line_height || !es->char_width)
+		return TRUE;
+
+	lines_per_page = (es->format_rect.bottom - es->format_rect.top) / es->line_height;
 
 	if (es->style & ES_MULTILINE)
 	{
diff --git a/dlls/comctl32/tests/edit.c b/dlls/comctl32/tests/edit.c
index 763ade4831..e3b2f40804 100644
--- a/dlls/comctl32/tests/edit.c
+++ b/dlls/comctl32/tests/edit.c
@@ -1790,6 +1790,8 @@ static LRESULT CALLBACK test_class_proc(HWND hwnd, UINT message, WPARAM wParam,
             ok(r == 1, "Returned %ld, expected 1.\n", r);
             r = SendMessageA(hwnd, WM_SIZE, 0, 0x00100010);
             todo_wine ok(r == 1, "Returned %ld, expected 1.\n", r);
+            r = SendMessageA(hwnd, EM_LINESCROLL, 1, 1);
+            ok(r == 1, "Returned %ld, expected 1.\n", r);
 
             return result;
 
@@ -1800,6 +1802,8 @@ static LRESULT CALLBACK test_class_proc(HWND hwnd, UINT message, WPARAM wParam,
             ok(r == 1, "Returned %ld, expected 1.\n", r);
             r = SendMessageA(hwnd, WM_SIZE, 0, 0x00100010);
             todo_wine ok(r == 1, "Returned %ld, expected 1.\n", r);
+            r = SendMessageA(hwnd, EM_LINESCROLL, 1, 1);
+            ok(r == 1, "Returned %ld, expected 1.\n", r);
 
             break;
     }
-- 
2.20.1