From a64a475ede0a0114cff313acaa9e63a8fb180cfd Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ond=C5=99ej=20Majerech?= Date: Tue, 19 Aug 2014 15:59:45 +0200 Subject: [PATCH] Don't underrun the vertex array of empty polygons MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Reviewed-by: Pekka Paalanen --- src/vertex-clipping.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/src/vertex-clipping.c b/src/vertex-clipping.c index db527e14..2bb8c0ab 100644 --- a/src/vertex-clipping.c +++ b/src/vertex-clipping.c @@ -206,6 +206,9 @@ clip_polygon_left(struct clip_context *ctx, const struct polygon8 *src, 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 @@ clip_polygon_right(struct clip_context *ctx, const struct polygon8 *src, 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 @@ clip_polygon_top(struct clip_context *ctx, const struct polygon8 *src, 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 @@ clip_polygon_bottom(struct clip_context *ctx, const struct polygon8 *src, 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]);