[PATCH] cliptest: Don't underrun the vertex array of empty polygons.

[Ondřej Majerech]

This silences the following warning:

  clients/cliptest.c:277:22: warning: array subscript is below array
  bounds [-Warray-bounds]
    ctx->prev.x = src->x[src->n - 1];

Signed-off-by: Ondřej Majerech <oxyd.oxyd at gmail.com>
---
 clients/cliptest.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/clients/cliptest.c b/clients/cliptest.c
index 907c5d4..20b3776 100644
--- a/clients/cliptest.c
+++ b/clients/cliptest.c
@@ -287,6 +287,9 @@ clip_polygon_left(struct clip_context *ctx, const struct polygon8 *src,
 	enum path_transition trans;
 	int i;
 
+	if (src->n == 0)
+		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]);
@@ -303,6 +306,9 @@ clip_polygon_right(struct clip_context *ctx, const struct polygon8 *src,
 	enum path_transition trans;
 	int i;
 
+	if (src->n == 0)
+		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]);
@@ -319,6 +325,9 @@ clip_polygon_top(struct clip_context *ctx, const struct polygon8 *src,
 	enum path_transition trans;
 	int i;
 
+	if (src->n == 0)
+		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]);
@@ -335,6 +344,9 @@ clip_polygon_bottom(struct clip_context *ctx, const struct polygon8 *src,
 	enum path_transition trans;
 	int i;
 
+	if (src->n == 0)
+		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]);
-- 
2.0.4