From: Sandro Santilli <strk@keybit.net>
Date: Thu, 29 Nov 2012 18:30:48 +0000 (+0000)
Subject: Ensure ST_Line_Interpolate_Point always returns POINT (#2108)
X-Git-Tag: 2.1.0beta2~347
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=a1df0584c32b0e608d490ca2ef3154ced67baf34;p=postgis

Ensure ST_Line_Interpolate_Point always returns POINT (#2108)

git-svn-id: http://svn.osgeo.org/postgis/trunk@10757 b70326c6-7e19-0410-871a-916f4a2858ee
---

diff --git a/postgis/lwgeom_functions_analytic.c b/postgis/lwgeom_functions_analytic.c
index 94a76e180..868dc2cea 100644
--- a/postgis/lwgeom_functions_analytic.c
+++ b/postgis/lwgeom_functions_analytic.c
@@ -80,6 +80,7 @@ PG_FUNCTION_INFO_V1(LWGEOM_line_interpolate_point);
 Datum LWGEOM_line_interpolate_point(PG_FUNCTION_ARGS)
 {
 	GSERIALIZED *gser = (GSERIALIZED *)PG_DETOAST_DATUM(PG_GETARG_DATUM(0));
+	GSERIALIZED *result;
 	double distance = PG_GETARG_FLOAT8(1);
 	LWLINE *line;
 	LWGEOM *geom;
@@ -101,6 +102,15 @@ Datum LWGEOM_line_interpolate_point(PG_FUNCTION_ARGS)
 		PG_RETURN_NULL();
 	}
 
+	/* Empty.InterpolatePoint == Point Empty */
+	if ( gserialized_is_empty(gser) )
+	{
+		geom = lwpoint_construct_empty(gserialized_get_srid(gser), gserialized_has_z(gser), gserialized_has_m(gser));
+		result = geometry_serialize(lwpoint_as_lwgeom(geom));
+		lwgeom_free(geom);
+		PG_RETURN_POINTER(result);
+	}
+
 	geom = lwgeom_from_gserialized(gser);
 	line = lwgeom_as_lwline(geom);
 	ipa = line->points;
diff --git a/regress/tickets.sql b/regress/tickets.sql
index d19f58302..bb050b03f 100644
--- a/regress/tickets.sql
+++ b/regress/tickets.sql
@@ -788,6 +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 '#2108', ST_AsEWKT(ST_Line_Interpolate_Point('SRID=3395;LINESTRING M EMPTY'::geometry, 0.5));
 SELECT '#2117', ST_AsEWKT(ST_PointOnSurface('SRID=3395;MULTIPOLYGON M EMPTY'::geometry));
 
 -- Clean up
diff --git a/regress/tickets_expected b/regress/tickets_expected
index d999778bb..e0f691fa2 100644
--- a/regress/tickets_expected
+++ b/regress/tickets_expected
@@ -240,4 +240,5 @@ 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)
+#2108|SRID=3395;POINTM EMPTY
 #2117|SRID=3395;POINTM EMPTY