From cf7dc0a2a6a3e21173556965d533ed041afde225 Mon Sep 17 00:00:00 2001
From: Sandro Santilli <strk@keybit.net>
Date: Fri, 1 Oct 2004 07:51:00 +0000
Subject: [PATCH] Added runtime cast functions.

git-svn-id: http://svn.osgeo.org/postgis/trunk@917 b70326c6-7e19-0410-871a-916f4a2858ee
---
 lwgeom/liblwgeom.h | 17 ++++++++++++++
 lwgeom/lwgeom.c    | 57 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 74 insertions(+)

diff --git a/lwgeom/liblwgeom.h b/lwgeom/liblwgeom.h
index bf0ba3e8c..1bc4e0d6c 100644
--- a/lwgeom/liblwgeom.h
+++ b/lwgeom/liblwgeom.h
@@ -225,6 +225,23 @@ typedef struct
 	LWGEOM **geoms;
 } LWCOLLECTION; 
 
+// Casts LWGEOM->LW* (return NULL if cast is illegal)
+LWMPOLY *lwgeom_as_lwmpoly(LWGEOM *lwgeom);
+LWMLINE *lwgeom_as_lwmline(LWGEOM *lwgeom);
+LWMPOINT *lwgeom_as_lwmpoint(LWGEOM *lwgeom);
+LWCOLLECTION *lwgeom_as_lwcollection(LWGEOM *lwgeom);
+LWPOLY *lwgeom_as_lwpoly(LWGEOM *lwgeom);
+LWLINE *lwgeom_as_lwline(LWGEOM *lwgeom);
+LWPOINT *lwgeom_as_lwpoint(LWGEOM *lwgeom);
+
+// Casts LW*->LWGEOM (always cast)
+LWGEOM *lwmpoly_as_lwgeom(LWMPOLY *obj);
+LWGEOM *lwmline_as_lwgeom(LWMLINE *obj);
+LWGEOM *lwmpoint_as_lwgeom(LWMPOINT *obj);
+LWGEOM *lwcollection_as_lwgeom(LWCOLLECTION *obj);
+LWGEOM *lwpoly_as_lwgeom(LWPOLY *obj);
+LWGEOM *lwline_as_lwgeom(LWLINE *obj);
+LWGEOM *lwpoint_as_lwgeom(LWPOINT *obj);
 //-------------------------------------------------------------
 
 // copies a point from the point array into the parameter point
diff --git a/lwgeom/lwgeom.c b/lwgeom/lwgeom.c
index 6f01ad70e..bc96c4418 100644
--- a/lwgeom/lwgeom.c
+++ b/lwgeom/lwgeom.c
@@ -185,3 +185,60 @@ lwgeom_compute_bbox(LWGEOM *lwgeom)
 	if ( lwgeom_compute_bbox_p(lwgeom, result) ) return result;
 	else return NULL;
 }
+
+LWPOINT *
+lwgeom_as_lwpoint(LWGEOM *lwgeom)
+{
+	if ( lwgeom->type == POINTTYPE ) return (LWPOINT *)lwgeom;
+	else return NULL;
+}
+
+LWLINE *
+lwgeom_as_lwline(LWGEOM *lwgeom)
+{
+	if ( lwgeom->type == LINETYPE ) return (LWLINE *)lwgeom;
+	else return NULL;
+}
+
+LWPOLY *
+lwgeom_as_lwpoly(LWGEOM *lwgeom)
+{
+	if ( lwgeom->type == POLYGONTYPE ) return (LWPOLY *)lwgeom;
+	else return NULL;
+}
+
+LWCOLLECTION *
+lwgeom_as_lwcollection(LWGEOM *lwgeom)
+{
+	if ( lwgeom->type >= MULTIPOINTTYPE ) return (LWCOLLECTION *)lwgeom;
+	else return NULL;
+}
+
+LWMPOINT *
+lwgeom_as_lwmpoint(LWGEOM *lwgeom)
+{
+	if ( lwgeom->type == MULTIPOINTTYPE ) return (LWMPOINT *)lwgeom;
+	else return NULL;
+}
+
+LWMLINE *
+lwgeom_as_lwmline(LWGEOM *lwgeom)
+{
+	if ( lwgeom->type == MULTILINETYPE ) return (LWMLINE *)lwgeom;
+	else return NULL;
+}
+
+LWMPOLY *
+lwgeom_as_lwmpoly(LWGEOM *lwgeom)
+{
+	if ( lwgeom->type == MULTIPOLYGONTYPE ) return (LWMPOLY *)lwgeom;
+	else return NULL;
+}
+
+LWGEOM *lwmpoly_as_lwgeom(LWMPOLY *obj) { return (LWGEOM *)obj; }
+LWGEOM *lwmline_as_lwgeom(LWMLINE *obj) { return (LWGEOM *)obj; }
+LWGEOM *lwmpoint_as_lwgeom(LWMPOINT *obj) { return (LWGEOM *)obj; }
+LWGEOM *lwcollection_as_lwgeom(LWCOLLECTION *obj) { return (LWGEOM *)obj; }
+LWGEOM *lwpoly_as_lwgeom(LWPOLY *obj) { return (LWGEOM *)obj; }
+LWGEOM *lwline_as_lwgeom(LWLINE *obj) { return (LWGEOM *)obj; }
+LWGEOM *lwpoint_as_lwgeom(LWPOINT *obj) { return (LWGEOM *)obj; }
-- 
2.40.0