Separate GEOS part of 'buildarea' function from POSTGIS part of it (might eventually...

git-svn-id: http://svn.osgeo.org/postgis/trunk@5229 b70326c6-7e19-0410-871a-916f4a2858ee

diff --git a/postgis/lwgeom_geos.c b/postgis/lwgeom_geos.c
index 07151fa2ac253a669c2307a7dcb2766316a92a71..95384ebe8672996d3aba0ab431a9e3b90271a9db 100644 (file)
--- a/postgis/lwgeom_geos.c
+++ b/postgis/lwgeom_geos.c
@@ -102,6 +102,111 @@ errorlogger(const char *fmt, ...)
 }
 
 
+/*
+ * This function would better be moved to the GEOS C-API,
+ * but isn't available up to 3.2.0
+ */
+GEOSGeometry* LWGEOM_GEOS_buildArea(const GEOSGeometry* geom_in);
+GEOSGeometry*
+LWGEOM_GEOS_buildArea(const GEOSGeometry* geom_in)
+{
+       GEOSGeometry *tmp;
+       GEOSGeometry *geos_result, *shp;
+       GEOSGeometry const *vgeoms[1];
+       unsigned int i, ngeoms;
+
+       vgeoms[0] = geom_in;
+       geos_result = GEOSPolygonize(vgeoms, 1);
+
+       POSTGIS_DEBUGF(3, "GEOSpolygonize returned @ %p", geos_result);
+
+       /* Null return from GEOSpolygonize (an exception) */
+       if ( ! geos_result ) return 0;
+
+       /*
+        * We should now have a collection
+        */
+#if PARANOIA_LEVEL > 0
+       if ( GEOSGeometryTypeId(geos_result) != COLLECTIONTYPE )
+       {
+               GEOSGeom_destroy(geos_result);
+               lwerror("Unexpected return from GEOSpolygonize");
+               return 0;
+       }
+#endif
+
+       ngeoms = GEOSGetNumGeometries(geos_result);
+
+       POSTGIS_DEBUGF(3, "GEOSpolygonize: ngeoms in polygonize output: %d", ngeoms);
+
+       /*
+        * No geometries in collection, early out
+        */
+       if ( ngeoms == 0 )
+       {
+               return geos_result;
+       }
+
+       /*
+        * Return first geometry if we only have one in collection,
+        * to avoid the unnecessary Geometry clone below.
+        */
+       if ( ngeoms == 1 )
+       {
+               tmp = (GEOSGeometry *)GEOSGetGeometryN(geos_result, 0);
+               if ( ! tmp ) return 0; /* exception */
+               shp = GEOSGeom_clone(tmp);
+               GEOSGeom_destroy(geos_result); /* only safe after the clone above */
+               return shp;
+       }
+
+       /*
+        * Iteratively invoke symdifference on outer rings
+        * as suggested by Carl Anderson:
+        * postgis-devel/2005-December/001805.html
+        */
+       shp = NULL;
+       for (i=0; i<ngeoms; ++i)
+       {
+               GEOSGeom extring;
+               GEOSCoordSeq sq;
+
+               /*
+                * Construct a Polygon from geometry i exterior ring
+                * We don't use GEOSGeom_clone on the ExteriorRing
+                * due to a bug in CAPI contained in GEOS 2.2 branch
+                * failing to properly return a LinearRing from
+                * a LinearRing clone.
+                */
+               sq=GEOSCoordSeq_clone(GEOSGeom_getCoordSeq(
+                                         GEOSGetExteriorRing(GEOSGetGeometryN( geos_result, i))
+                                     ));
+               extring = GEOSGeom_createPolygon(
+                             GEOSGeom_createLinearRing(sq),
+                             NULL, 0
+                         );
+
+               if ( extring == NULL ) /* exception */
+               {
+                       lwerror("GEOSCreatePolygon threw an exception");
+                       return 0;
+               }
+
+               if ( shp == NULL )
+               {
+                       shp = extring;
+               }
+               else
+               {
+                       tmp = GEOSSymDifference(shp, extring);
+                       GEOSGeom_destroy(shp);
+                       GEOSGeom_destroy(extring);
+                       shp = tmp;
+               }
+       }
+
+       return shp;
+}
 
 PG_FUNCTION_INFO_V1(postgis_geos_version);
 Datum postgis_geos_version(PG_FUNCTION_ARGS)
@@ -3158,10 +3263,10 @@ LWGEOM2GEOS(LWGEOM *lwgeom)
        return g;
 }
 
-const GEOSGeometry *
+GEOSGeometry *
 POSTGIS2GEOS(PG_LWGEOM *pglwgeom)
 {
-       const GEOSGeometry *ret;
+       GEOSGeometry *ret;
        LWGEOM *lwgeom = lwgeom_deserialize(SERIALIZED_FORM(pglwgeom));
        if ( ! lwgeom )
        {
@@ -3371,11 +3476,9 @@ PG_FUNCTION_INFO_V1(LWGEOM_buildarea);
 Datum LWGEOM_buildarea(PG_FUNCTION_ARGS)
 {
        int is3d = 0;
-       unsigned int i, ngeoms;
        PG_LWGEOM *result;
-       LWGEOM *lwg;
-       GEOSGeometry *geos_result, *shp;
-       GEOSGeometry const *vgeoms[1];
+       GEOSGeometry* geos_in;
+       GEOSGeometry* geos_out;
        int SRID=-1;
 #if POSTGIS_DEBUG_LEVEL >= 3
        static int call=1;
@@ -3395,105 +3498,25 @@ Datum LWGEOM_buildarea(PG_FUNCTION_ARGS)
 
        initGEOS(lwnotice, lwerror);
 
-       vgeoms[0] = (const GEOSGeometry *)POSTGIS2GEOS(geom);
-       geos_result = GEOSPolygonize(vgeoms, 1);
-       GEOSGeom_destroy((GEOSGeometry *)vgeoms[0]);
-
-       POSTGIS_DEBUGF(3, "GEOSpolygonize returned @ %p", geos_result);
-
-       /* Null return from GEOSpolygonize */
-       if ( ! geos_result ) PG_RETURN_NULL();
+       geos_in = POSTGIS2GEOS(geom);
+       geos_out = LWGEOM_GEOS_buildArea(geos_in);
+       GEOSGeom_destroy(geos_in);
 
-       /*
-        * We should now have a collection
-        */
-#if PARANOIA_LEVEL > 0
-       if ( GEOSGeometryTypeId(geos_result) != COLLECTIONTYPE )
+       if ( ! geos_out ) /* exception thrown.. */
        {
-               GEOSGeom_destroy(geos_result);
-               lwerror("Unexpected return from GEOSpolygonize");
                PG_RETURN_NULL();
        }
-#endif
-
-       ngeoms = GEOSGetNumGeometries(geos_result);
 
-       POSTGIS_DEBUGF(3, "GEOSpolygonize: ngeoms in polygonize output: %d", ngeoms);
-
-       /*
-        * No geometries in collection, return NULL
-        */
-       if ( ngeoms == 0 )
+       /* If no geometries are in result collection, return NULL */
+       if ( GEOSGetNumGeometries(geos_out) == 0 )
        {
-               GEOSGeom_destroy(geos_result);
+               GEOSGeom_destroy(geos_out);
                PG_RETURN_NULL();
        }
 
-       /*
-        * Return first geometry if we only have one in collection,
-        * to avoid the unnecessary Geometry clone below.
-        */
-       if ( ngeoms == 1 )
-       {
-               shp = (GEOSGeometry *)GEOSGetGeometryN(geos_result, 0);
-               lwg = GEOS2LWGEOM(shp, is3d);
-               lwg->SRID = SRID;
-               result = pglwgeom_serialize(lwg);
-               lwgeom_release(lwg);
-               GEOSGeom_destroy(geos_result);
-               PG_RETURN_POINTER(result);
-       }
-
-       /*
-        * Iteratively invoke symdifference on outer rings
-        * as suggested by Carl Anderson:
-        * postgis-devel/2005-December/001805.html
-        */
-       shp = NULL;
-       for (i=0; i<ngeoms; ++i)
-       {
-               GEOSGeom extring, tmp;
-               GEOSCoordSeq sq;
-
-               /*
-                * Construct a Polygon from geometry i exterior ring
-                * We don't use GEOSGeom_clone on the ExteriorRing
-                * due to a bug in CAPI contained in GEOS 2.2 branch
-                * failing to properly return a LinearRing from
-                * a LinearRing clone.
-                */
-               sq=GEOSCoordSeq_clone(GEOSGeom_getCoordSeq(
-                                         GEOSGetExteriorRing(GEOSGetGeometryN( geos_result, i))
-                                     ));
-               extring = GEOSGeom_createPolygon(
-                             GEOSGeom_createLinearRing(sq),
-                             NULL, 0
-                         );
-
-               if ( extring == NULL ) /* exception */
-               {
-                       lwerror("GEOSCreatePolygon threw an exception");
-                       PG_RETURN_NULL();
-               }
-
-               if ( shp == NULL )
-               {
-                       shp = extring;
-               }
-               else
-               {
-                       tmp = GEOSSymDifference(shp, extring);
-                       GEOSGeom_destroy(shp);
-                       GEOSGeom_destroy(extring);
-                       shp = tmp;
-               }
-       }
-
-       GEOSGeom_destroy(geos_result);
-
-       GEOSSetSRID(shp, SRID);
-       result = GEOS2POSTGIS(shp, is3d);
-       GEOSGeom_destroy(shp);
+       GEOSSetSRID(geos_out, SRID);
+       result = GEOS2POSTGIS(geos_out, is3d);
+       GEOSGeom_destroy(geos_out);
 
 #if PARANOIA_LEVEL > 0
        if ( result == NULL )

diff --git a/postgis/lwgeom_geos.h b/postgis/lwgeom_geos.h
index 5e3377621902f18bd8739a565fd049006ed13fa3..deb559336854b4fe34d602d9caa26c39c48e9c69 100644 (file)
--- a/postgis/lwgeom_geos.h
+++ b/postgis/lwgeom_geos.h
@@ -43,7 +43,7 @@
 */
 
 PG_LWGEOM *GEOS2POSTGIS(GEOSGeom geom, char want3d);
-const GEOSGeometry * POSTGIS2GEOS(PG_LWGEOM *g);
+GEOSGeometry * POSTGIS2GEOS(PG_LWGEOM *g);
 
 LWGEOM *GEOS2LWGEOM(const GEOSGeometry *geom, char want3d);
 GEOSGeometry * LWGEOM2GEOS(LWGEOM *g);