Don't underrun the vertex array of empty polygons
This silences the following warning:
src/vertex-clipping.c:196:22: warning: array subscript is below array
bounds [-Warray-bounds]
ctx->prev.x = src->x[src->n - 1];
[Pekka Paalanen: the src->n < 2 comparison comes from the fact that a
polygon with 0 or 1 points is not a polygon. A polygon with 2 points is
still degenerate, but at least it has two edges that can be clipped.]
Signed-off-by: Ondřej Majerech <oxyd.oxyd@gmail.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
diff --git a/src/vertex-clipping.c b/src/vertex-clipping.c
index db527e1..2bb8c0a 100644
--- a/src/vertex-clipping.c
+++ b/src/vertex-clipping.c
@@ -206,6 +206,9 @@
enum path_transition trans;
int i;
+ if (src->n < 2)
+ return 0;
+
clip_context_prepare(ctx, src, dst_x, dst_y);
for (i = 0; i < src->n; i++) {
trans = path_transition_left_edge(ctx, src->x[i], src->y[i]);
@@ -222,6 +225,9 @@
enum path_transition trans;
int i;
+ if (src->n < 2)
+ return 0;
+
clip_context_prepare(ctx, src, dst_x, dst_y);
for (i = 0; i < src->n; i++) {
trans = path_transition_right_edge(ctx, src->x[i], src->y[i]);
@@ -238,6 +244,9 @@
enum path_transition trans;
int i;
+ if (src->n < 2)
+ return 0;
+
clip_context_prepare(ctx, src, dst_x, dst_y);
for (i = 0; i < src->n; i++) {
trans = path_transition_top_edge(ctx, src->x[i], src->y[i]);
@@ -254,6 +263,9 @@
enum path_transition trans;
int i;
+ if (src->n < 2)
+ return 0;
+
clip_context_prepare(ctx, src, dst_x, dst_y);
for (i = 0; i < src->n; i++) {
trans = path_transition_bottom_edge(ctx, src->x[i], src->y[i]);