From ba9576e7f2b67c0311352085fa961dc8fe69f0b4 Mon Sep 17 00:00:00 2001
From: Paul Ramsey <pramsey@cleverelephant.ca>
Date: Wed, 22 Jun 2011 22:09:47 +0000
Subject: [PATCH] ST_ForceRHR POLYGON EMPTY crash (#710)

git-svn-id: http://svn.osgeo.org/postgis/trunk@7446 b70326c6-7e19-0410-871a-916f4a2858ee
---
 liblwgeom/lwpoly.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/liblwgeom/lwpoly.c b/liblwgeom/lwpoly.c
index b05db7b2d..be6063ab0 100644
--- a/liblwgeom/lwpoly.c
+++ b/liblwgeom/lwpoly.c
@@ -503,18 +503,19 @@ lwpoly_force_clockwise(LWPOLY *poly)
 {
 	int i;
 
+	/* No-op empties */
+	if ( lwpoly_is_empty(poly) )
+		return;
+
+	/* External ring */
 	if ( ptarray_isccw(poly->rings[0]) )
-	{
 		ptarray_reverse(poly->rings[0]);
-	}
 
+	/* Internal rings */
 	for (i=1; i<poly->nrings; i++)
-	{
 		if ( ! ptarray_isccw(poly->rings[i]) )
-		{
 			ptarray_reverse(poly->rings[i]);
-		}
-	}
+
 }
 
 void
-- 
2.50.1