BOX2D_combine()

Datum BOX2D_combine

(

PG_FUNCTION_ARGS

)

Definition at line 418 of file lwgeom_box.c.

{
        static const uint32_t box2d_idx = 0;
        static const uint32_t geom_idx = 1;
        GBOX *a,*b;
        GBOX box, *result;
 
        if (PG_ARGISNULL(box2d_idx) && PG_ARGISNULL(geom_idx))
        {
                PG_RETURN_NULL(); /* combine_box2d(null,null) => null */
        }
 
        result = (GBOX *)palloc(sizeof(GBOX));
 
        if (PG_ARGISNULL(box2d_idx))
        {
                /* empty geom would make getbox2d_p return NULL */
                if (!gserialized_datum_get_gbox_p(PG_GETARG_DATUM(geom_idx), &box))
                        PG_RETURN_NULL();
                memcpy(result, &box, sizeof(GBOX));
                PG_RETURN_POINTER(result);
        }
 
        /* combine_bbox(BOX3D, null) => BOX3D */
        if (PG_ARGISNULL(geom_idx))
        {
                memcpy(result, (char *)PG_GETARG_DATUM(box2d_idx), sizeof(GBOX));
                PG_RETURN_POINTER(result);
        }
 
        /*combine_bbox(BOX3D, geometry) => union(BOX3D, geometry->bvol) */
 
        if (!gserialized_datum_get_gbox_p(PG_GETARG_DATUM(geom_idx), &box))
        {
                /* must be the empty geom */
                memcpy(result, (char *)PG_GETARG_DATUM(box2d_idx), sizeof(GBOX));
                PG_RETURN_POINTER(result);
        }
 
        a = (GBOX *)PG_GETARG_DATUM(box2d_idx);
        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_datum_get_gbox_p(), result, GBOX::xmax, GBOX::xmin, GBOX::ymax, and GBOX::ymin.

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