From 5635299b47e4742cc2ddb070147397a476ee1c9f Mon Sep 17 00:00:00 2001
From: Paul Ramsey <pramsey@cleverelephant.ca>
Date: Thu, 17 Sep 2009 02:33:49 +0000
Subject: [PATCH] Add lwgeom_is_empty() test

git-svn-id: http://svn.osgeo.org/postgis/trunk@4507 b70326c6-7e19-0410-871a-916f4a2858ee
---
 liblwgeom/liblwgeom.h |  6 ++++
 liblwgeom/lwgeom.c    | 69 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 75 insertions(+)

diff --git a/liblwgeom/liblwgeom.h b/liblwgeom/liblwgeom.h
index 356135a84..1c9f84a03 100644
--- a/liblwgeom/liblwgeom.h
+++ b/liblwgeom/liblwgeom.h
@@ -1260,6 +1260,12 @@ extern int lwgeom_needs_bbox(LWGEOM *geom);
 extern int lwgeom_count_vertices(LWGEOM *geom);
 extern int32 lwgeom_npoints(uchar *serialized);
 
+/**
+* Return true of false depending on whether a geometry is an "empty" 
+* geometry (no vertices members)
+*/
+extern int lwgeom_is_empty(LWGEOM *geom);
+
 /* Is lwgeom1 geometrically equal to lwgeom2 ? */
 char lwgeom_same(const LWGEOM *lwgeom1, const LWGEOM *lwgeom2);
 char ptarray_same(const POINTARRAY *pa1, const POINTARRAY *pa2);
diff --git a/liblwgeom/lwgeom.c b/liblwgeom/lwgeom.c
index eb830cc60..879be127e 100644
--- a/liblwgeom/lwgeom.c
+++ b/liblwgeom/lwgeom.c
@@ -1063,3 +1063,72 @@ int lwgeom_count_vertices(LWGEOM *geom)
 	LWDEBUGF(3, "counted %d vertices", result);
 	return result;
 }
+
+static int lwpoint_is_empty(LWPOINT *point)
+{
+	if( ! point->point || point->point->npoints == 0 )
+		return LW_TRUE;
+	return LW_FALSE;
+}
+
+static int lwline_is_empty(LWLINE *line)
+{
+	if( !line->points || line->points->npoints == 0 )
+		return LW_TRUE;
+	return LW_FALSE;
+}
+
+static int lwpoly_is_empty(LWPOLY *poly)
+{
+	if( !poly->rings || poly->nrings == 0 )
+		return LW_TRUE;
+	return LW_FALSE;
+}
+
+static int lwcircstring_is_empty(LWCIRCSTRING *circ)
+{
+	if( !circ->points || circ->points->npoints == 0 )
+		return LW_TRUE;
+	return LW_FALSE;
+}
+
+static int lwcollection_is_empty(LWCOLLECTION *col)
+{
+	if( !col->geoms || col->ngeoms == 0 )
+		return LW_TRUE;
+	return LW_FALSE;
+}
+
+int lwgeom_is_empty(LWGEOM *geom)
+{
+	int result = LW_FALSE;
+	LWDEBUGF(4, "got type %d", TYPE_GETTYPE(geom->type));
+	switch (TYPE_GETTYPE(geom->type))
+	{
+		case POINTTYPE:
+			return lwpoint_is_empty((LWPOINT*)geom);
+			break;
+		case LINETYPE:
+			return lwline_is_empty((LWLINE*)geom);
+			break;
+		case CIRCSTRINGTYPE:
+			return lwcircstring_is_empty((LWCIRCSTRING*)geom);
+			break;
+		case POLYGONTYPE:
+			return lwpoly_is_empty((LWPOLY*)geom);
+			break;
+		case MULTIPOINTTYPE:
+		case MULTILINETYPE:
+		case MULTIPOLYGONTYPE:
+		case COMPOUNDTYPE:
+		case MULTICURVETYPE:
+		case MULTISURFACETYPE:
+		case COLLECTIONTYPE:
+			return lwcollection_is_empty((LWCOLLECTION *)geom);
+			break;
+		default:
+			lwerror("unsupported input geometry type: %d", TYPE_GETTYPE(geom->type));
+			break;
+	}
+	return result;
+}
\ No newline at end of file
-- 
2.49.0