From 46025a47a12eb450a3cb96c16c53f42b77d0e9cf Mon Sep 17 00:00:00 2001
From: Sandro Santilli <strk@keybit.net>
Date: Mon, 29 Jun 2015 15:28:37 +0000
Subject: [PATCH] Add lwgeom_is_simple method in liblwgeom, use from postgis
 module

git-svn-id: http://svn.osgeo.org/postgis/trunk@13740 b70326c6-7e19-0410-871a-916f4a2858ee
---
 NEWS                     |  4 +++-
 liblwgeom/liblwgeom.h.in |  8 ++++++++
 liblwgeom/lwgeom_geos.c  | 32 ++++++++++++++++++++++++++++++++
 postgis/lwgeom_geos.c    | 22 ++++++----------------
 4 files changed, 49 insertions(+), 17 deletions(-)

diff --git a/NEWS b/NEWS
index fdf642a48..bab64e533 100644
--- a/NEWS
+++ b/NEWS
@@ -31,7 +31,9 @@ PostGIS 2.2.0
 
  * New Features *
 
-  - #3117, Add SFCGAL 1.1 support: add ST_3DDifference, ST_3DUnion, ST_Volume, ST_MakeSolid, ST_IsSolid (Vincent Mora / Oslandia)
+  - New lwgeom_is_simple method in liblwgeom
+  - #3117, Add SFCGAL 1.1 support: add ST_3DDifference, ST_3DUnion,
+           ST_Volume, ST_MakeSolid, ST_IsSolid (Vincent Mora / Oslandia)
   - #3169, ST_ApproximateMedialAxis (Sandro Santilli)
   - ST_CPAWithin (Sandro Santilli / Boundless)
   - Add |=| operator with CPA semantic and KNN support with PgSQL 9.5+
diff --git a/liblwgeom/liblwgeom.h.in b/liblwgeom/liblwgeom.h.in
index 1e381e4b2..c56107ef3 100644
--- a/liblwgeom/liblwgeom.h.in
+++ b/liblwgeom/liblwgeom.h.in
@@ -2064,6 +2064,14 @@ LWGEOM* lwgeom_sharedpaths(const LWGEOM* geom1, const LWGEOM* geom2);
  */
 LWGEOM* lwgeom_offsetcurve(const LWLINE *lwline, double size, int quadsegs, int joinStyle, double mitreLimit);
 
+/*
+ * Return true if the input geometry is "simple" as per OGC defn.
+ *
+ * @return 1 if simple, 0 if non-simple, -1 on exception (lwerror is called
+ *         in that case)
+ */
+int lwgeom_is_simple(const LWGEOM *lwgeom);
+
 
 /*******************************************************************************
  * PROJ4-dependent extra functions on LWGEOM
diff --git a/liblwgeom/lwgeom_geos.c b/liblwgeom/lwgeom_geos.c
index 893c8d32c..9fd8827ca 100644
--- a/liblwgeom/lwgeom_geos.c
+++ b/liblwgeom/lwgeom_geos.c
@@ -1195,6 +1195,38 @@ lwgeom_buildarea(const LWGEOM *geom)
 	return geom_out;
 }
 
+int
+lwgeom_is_simple(const LWGEOM *geom)
+{
+	GEOSGeometry* geos_in;
+	int simple;
+
+	/* Empty is always simple */
+	if ( lwgeom_is_empty(geom) )
+	{
+		return 1;
+	}
+
+	initGEOS(lwnotice, lwgeom_geos_error);
+
+	geos_in = LWGEOM2GEOS(geom, 0);
+	if ( 0 == geos_in )   /* exception thrown at construction */
+	{
+		lwerror("First argument geometry could not be converted to GEOS: %s", lwgeom_geos_errmsg);
+		return -1;
+	}
+	simple = GEOSisSimple(geos_in);
+	GEOSGeom_destroy(geos_in);
+
+	if ( simple == 2 ) /* exception thrown */
+	{
+		lwerror("lwgeom_is_simple: %s", lwgeom_geos_errmsg);
+		return -1;
+	}
+
+	return simple ? 1 : 0;
+}
+
 /* ------------ end of BuildArea stuff ---------------------------------------------------------------------} */
 
 LWGEOM*
diff --git a/postgis/lwgeom_geos.c b/postgis/lwgeom_geos.c
index 789030b28..c3d1e9003 100644
--- a/postgis/lwgeom_geos.c
+++ b/postgis/lwgeom_geos.c
@@ -3132,7 +3132,7 @@ PG_FUNCTION_INFO_V1(issimple);
 Datum issimple(PG_FUNCTION_ARGS)
 {
 	GSERIALIZED *geom;
-	GEOSGeometry *g1;
+	LWGEOM *lwgeom_in;
 	int result;
 
 	POSTGIS_DEBUG(2, "issimple called");
@@ -3142,25 +3142,15 @@ Datum issimple(PG_FUNCTION_ARGS)
 	if ( gserialized_is_empty(geom) )
 		PG_RETURN_BOOL(TRUE);
 
-	initGEOS(lwpgnotice, lwgeom_geos_error);
-
-	g1 = (GEOSGeometry *)POSTGIS2GEOS(geom);
-	if ( 0 == g1 )   /* exception thrown at construction */
-	{
-		HANDLE_GEOS_ERROR("First argument geometry could not be converted to GEOS");
-		PG_RETURN_NULL();
-	}
-	result = GEOSisSimple(g1);
-	GEOSGeom_destroy(g1);
+	lwgeom_in = lwgeom_from_gserialized(geom);
+	result = lwgeom_is_simple(lwgeom_in);
+	lwgeom_free(lwgeom_in) ;
+	PG_FREE_IF_COPY(geom, 0);
 
-	if (result == 2)
-	{
-		HANDLE_GEOS_ERROR("GEOSisSimple");
+	if (result == -1) {
 		PG_RETURN_NULL(); /*never get here */
 	}
 
-	PG_FREE_IF_COPY(geom, 0);
-
 	PG_RETURN_BOOL(result);
 }
 
-- 
2.40.0