From: Sandro Santilli <strk@keybit.net>
Date: Thu, 29 Nov 2012 18:13:47 +0000 (+0000)
Subject: Ensure ST_PointOnSurface always returns POINT (#2117)
X-Git-Tag: 2.1.0beta2~348
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=58a11eb5af1580e37c52c37a59f57d0882c7a604;p=postgis

Ensure ST_PointOnSurface always returns POINT (#2117)

git-svn-id: http://svn.osgeo.org/postgis/trunk@10755 b70326c6-7e19-0410-871a-916f4a2858ee
---

diff --git a/postgis/lwgeom_geos.c b/postgis/lwgeom_geos.c
index 758e9c4ab..c1d5236a2 100644
--- a/postgis/lwgeom_geos.c
+++ b/postgis/lwgeom_geos.c
@@ -1494,19 +1494,25 @@ Datum difference(PG_FUNCTION_ARGS)
 PG_FUNCTION_INFO_V1(pointonsurface);
 Datum pointonsurface(PG_FUNCTION_ARGS)
 {
-	GSERIALIZED *geom1;
+	LWGEOM *lwg;
+	GSERIALIZED *geom;
 	GEOSGeometry *g1, *g3;
 	GSERIALIZED *result;
 
-	geom1 = (GSERIALIZED *)PG_DETOAST_DATUM(PG_GETARG_DATUM(0));
+	geom = (GSERIALIZED *)PG_DETOAST_DATUM(PG_GETARG_DATUM(0));
 
-	/* Empty.PointOnSurface == Empty */
-	if ( gserialized_is_empty(geom1) )
-		PG_RETURN_POINTER(geom1);
+	/* Empty.PointOnSurface == Point Empty */
+	if ( gserialized_is_empty(geom) )
+	{
+		lwg = lwpoint_construct_empty(gserialized_get_srid(geom), gserialized_has_z(geom), gserialized_has_m(geom));
+		result = geometry_serialize(lwpoint_as_lwgeom(lwg));
+		lwgeom_free(lwg);
+		PG_RETURN_POINTER(result);
+	}
 
 	initGEOS(lwnotice, lwgeom_geos_error);
 
-	g1 = (GEOSGeometry *)POSTGIS2GEOS(geom1);
+	g1 = (GEOSGeometry *)POSTGIS2GEOS(geom);
 
 	if ( 0 == g1 )   /* exception thrown at construction */
 	{
@@ -1525,9 +1531,9 @@ Datum pointonsurface(PG_FUNCTION_ARGS)
 
 	POSTGIS_DEBUGF(3, "result: %s", GEOSGeomToWKT(g3) ) ;
 
-	GEOSSetSRID(g3, gserialized_get_srid(geom1));
+	GEOSSetSRID(g3, gserialized_get_srid(geom));
 
-	result = GEOS2POSTGIS(g3, gserialized_has_z(geom1));
+	result = GEOS2POSTGIS(g3, gserialized_has_z(geom));
 
 	if (result == NULL)
 	{
@@ -1540,7 +1546,7 @@ Datum pointonsurface(PG_FUNCTION_ARGS)
 	GEOSGeom_destroy(g1);
 	GEOSGeom_destroy(g3);
 
-	PG_FREE_IF_COPY(geom1, 0);
+	PG_FREE_IF_COPY(geom, 0);
 
 	PG_RETURN_POINTER(result);
 }
diff --git a/regress/tickets.sql b/regress/tickets.sql
index 9c2d112d5..d19f58302 100644
--- a/regress/tickets.sql
+++ b/regress/tickets.sql
@@ -788,5 +788,7 @@ FROM (SELECT 'POLYGON((1 1 1, 5 1 1,5 5 1, 1 5 1,1 1 1))'::geometry as a, 'LINES
      ) as foo;
 -- 2112 -- End
 
+SELECT '#2117', ST_AsEWKT(ST_PointOnSurface('SRID=3395;MULTIPOLYGON M EMPTY'::geometry));
+
 -- Clean up
 DELETE FROM spatial_ref_sys;
diff --git a/regress/tickets_expected b/regress/tickets_expected
index b798bcb03..d999778bb 100644
--- a/regress/tickets_expected
+++ b/regress/tickets_expected
@@ -240,3 +240,4 @@ ERROR:  invalid GML representation
 #2048|3|f|f
 #2112a|0|LINESTRING(2.5 2.5 1,2.5 2.5 1)
 #2112b|1|LINESTRING(1 1 1,1 0 1)
+#2117|SRID=3395;POINTM EMPTY