PostGIS  2.2.7dev-r@@SVN_REVISION@@
Datum LWGEOM_x_point ( PG_FUNCTION_ARGS  )

Definition at line 563 of file lwgeom_ogc.c.

References getPoint2d_p(), gserialized_get_type(), lwgeom_as_lwpoint(), lwgeom_from_gserialized(), lwgeom_is_empty(), LWPOINT::point, POINTTYPE, and POINT2D::x.

564 {
565  GSERIALIZED *geom;
566  LWGEOM *lwgeom;
567  LWPOINT *point = NULL;
568  POINT2D p;
569 
570  geom = PG_GETARG_GSERIALIZED_P(0);
571 
572  if ( gserialized_get_type(geom) != POINTTYPE )
573  lwpgerror("Argument to ST_X() must be a point");
574 
575  lwgeom = lwgeom_from_gserialized(geom);
576  point = lwgeom_as_lwpoint(lwgeom);
577 
578  if ( lwgeom_is_empty(lwgeom) )
579  PG_RETURN_NULL();
580 
581  getPoint2d_p(point->point, 0, &p);
582 
583  PG_FREE_IF_COPY(geom, 0);
584  PG_RETURN_FLOAT8(p.x);
585 }
uint32_t gserialized_get_type(const GSERIALIZED *s)
Extract the geometry type from the serialized form (it hides in the anonymous data area...
Definition: g_serialized.c:55
LWGEOM * lwgeom_from_gserialized(const GSERIALIZED *g)
Allocate a new LWGEOM from a GSERIALIZED.
LWPOINT * lwgeom_as_lwpoint(const LWGEOM *lwgeom)
Definition: lwgeom.c:80
POINTARRAY * point
Definition: liblwgeom.h:395
double x
Definition: liblwgeom.h:312
int getPoint2d_p(const POINTARRAY *pa, int n, POINT2D *point)
Definition: lwgeom_api.c:448
#define POINTTYPE
LWTYPE numbers, used internally by PostGIS.
Definition: liblwgeom.h:70
int lwgeom_is_empty(const LWGEOM *geom)
Return true or false depending on whether a geometry is an "empty" geometry (no vertices members) ...
Definition: lwgeom.c:1297

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