Added lwpoly_from_lwlines()

git-svn-id: http://svn.osgeo.org/postgis/trunk@1232 b70326c6-7e19-0410-871a-916f4a2858ee

diff --git a/lwgeom/lwpoly.c b/lwgeom/lwpoly.c
index 6622cfdcbb2289e3372f6012c4138f4e558c27d7..32d61a9e6b7cd329787cbdc4212dc6866f8c537b 100644 (file)
--- a/lwgeom/lwpoly.c
+++ b/lwgeom/lwpoly.c
@@ -540,3 +540,44 @@ lwpoly_same(const LWPOLY *p1, const LWPOLY *p2)
        }
        return 1;
 }
+
+/*
+ * Construct a polygon from a LWLINE being
+ * the shell and an array of LWLINE (possibly NULL) being holes.
+ * Pointarrays from intput geoms are cloned.
+ * SRID must be the same for each input line.
+ * Input lines must have at least 4 points, and be closed.
+ */
+LWPOLY *
+lwpoly_from_lwlines(const LWLINE *shell,
+       unsigned int nholes, const LWLINE **holes)
+{
+       unsigned int nrings;
+       POINTARRAY **rings = lwalloc((nholes+1)*sizeof(POINTARRAY *));
+       int SRID = shell->SRID;
+       LWPOLY *ret;
+
+       if ( shell->points->npoints < 4 )
+               lwerror("lwpoly_from_lwlines: shell must have at least 4 points");
+       if ( ! ptarray_isclosed2d(shell->points) )
+               lwerror("lwpoly_from_lwlines: shell must be closed");
+       rings[0] = ptarray_clone(shell->points);
+
+       for (nrings=1; nrings<=nholes; nrings++)
+       {
+               const LWLINE *hole = holes[nrings-1];
+
+               if ( hole->SRID != SRID )
+                       lwerror("lwpoly_from_lwlines: mixed SRIDs in input lines");
+
+               if ( hole->points->npoints < 4 )
+                       lwerror("lwpoly_from_lwlines: holes must have at least 4 points");
+               if ( ! ptarray_isclosed2d(hole->points) )
+                       lwerror("lwpoly_from_lwlines: holes must be closed");
+
+               rings[nrings] = ptarray_clone(hole->points);
+       }
+
+       ret = lwpoly_construct(SRID, NULL, nrings, rings);
+       return ret;
+}