BOX2D_combine()

Datum BOX2D_combine

(

PG_FUNCTION_ARGS

)

Definition at line 417 of file lwgeom_box.c.

{
        Pointer box2d_ptr = PG_GETARG_POINTER(0);
        Pointer geom_ptr = PG_GETARG_POINTER(1);
        GBOX *a,*b;
        GSERIALIZED *lwgeom;
        GBOX box, *result;
 
        if  ( (box2d_ptr == NULL) && (geom_ptr == NULL) )
        {
                PG_RETURN_NULL(); /* combine_box2d(null,null) => null */
        }
 
        result = (GBOX *)palloc(sizeof(GBOX));
 
        if (box2d_ptr == NULL)
        {
                lwgeom = PG_GETARG_GSERIALIZED_P(1);
                /* empty geom would make getbox2d_p return NULL */
                if ( ! gserialized_get_gbox_p(lwgeom, &box) ) PG_RETURN_NULL();
                memcpy(result, &box, sizeof(GBOX));
                PG_RETURN_POINTER(result);
        }
 
        /* combine_bbox(BOX3D, null) => BOX3D */
        if (geom_ptr == NULL)
        {
                memcpy(result, (char *)PG_GETARG_DATUM(0), sizeof(GBOX));
                PG_RETURN_POINTER(result);
        }
 
        /*combine_bbox(BOX3D, geometry) => union(BOX3D, geometry->bvol) */
 
        lwgeom = PG_GETARG_GSERIALIZED_P(1);
        if ( ! gserialized_get_gbox_p(lwgeom, &box) )
        {
                /* must be the empty geom */
                memcpy(result, (char *)PG_GETARG_DATUM(0), sizeof(GBOX));
                PG_RETURN_POINTER(result);
        }
 
        a = (GBOX *)PG_GETARG_DATUM(0);
        b = &box;
 
        result->xmax = Max(a->xmax, b->xmax);
        result->ymax = Max(a->ymax, b->ymax);
        result->xmin = Min(a->xmin, b->xmin);
        result->ymin = Min(a->ymin, b->ymin);
 
        PG_RETURN_POINTER(result);
}

References gserialized_get_gbox_p(), GBOX::xmax, GBOX::xmin, GBOX::ymax, and GBOX::ymin.

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