lwline_from_lwgeom_array()

LWLINE * lwline_from_lwgeom_array ( int32_t  srid, uint32_t  ngeoms, LWGEOM **  geoms  )

extern

Definition at line 151 of file lwline.c.

{
        uint32_t i;
        int hasz = LW_FALSE;
        int hasm = LW_FALSE;
        POINTARRAY *pa;
        LWLINE *line;
        POINT4D pt;
        LWPOINTITERATOR* it;
 
        /*
         * Find output dimensions, check integrity
         */
        for (i=0; i<ngeoms; i++)
        {
                if ( FLAGS_GET_Z(geoms[i]->flags) ) hasz = LW_TRUE;
                if ( FLAGS_GET_M(geoms[i]->flags) ) hasm = LW_TRUE;
                if ( hasz && hasm ) break; /* Nothing more to learn! */
        }
 
        /*
         * ngeoms should be a guess about how many points we have in input.
         * It's an underestimate for lines and multipoints */
        pa = ptarray_construct_empty(hasz, hasm, ngeoms);
 
        for ( i=0; i < ngeoms; i++ )
        {
                LWGEOM *g = geoms[i];
 
                if ( lwgeom_is_empty(g) ) continue;
 
                if ( g->type == POINTTYPE )
                {
                        lwpoint_getPoint4d_p((LWPOINT*)g, &pt);
                        ptarray_append_point(pa, &pt, LW_TRUE);
                }
                else if ( g->type == LINETYPE )
                {
                        /*
                         * Append the new line points, de-duplicating against the previous points.
                         * Duplicated points internal to the linestring are untouched.
                         */
                        ptarray_append_ptarray(pa, ((LWLINE*)g)->points, -1);
                }
                else if ( g->type == MULTIPOINTTYPE )
                {
                        it = lwpointiterator_create(g);
                        while(lwpointiterator_next(it, &pt))
                        {
                                ptarray_append_point(pa, &pt, LW_TRUE);
                        }
                        lwpointiterator_destroy(it);
                }
                else
                {
                        ptarray_free(pa);
                        lwerror("lwline_from_ptarray: invalid input type: %s", lwtype_name(g->type));
                        return NULL;
                }
        }
 
        if ( pa->npoints > 0 )
                line = lwline_construct(srid, NULL, pa);
        else  {
                /* Is this really any different from the above ? */
                ptarray_free(pa);
                line = lwline_construct_empty(srid, hasz, hasm);
        }
 
        return line;
}

References FLAGS_GET_M, FLAGS_GET_Z, LINETYPE, LW_FALSE, LW_TRUE, lwerror(), lwgeom_is_empty(), lwline_construct(), lwline_construct_empty(), lwpoint_getPoint4d_p(), lwpointiterator_create(), lwpointiterator_destroy(), lwpointiterator_next(), lwtype_name(), MULTIPOINTTYPE, POINTARRAY::npoints, POINTTYPE, ptarray_append_point(), ptarray_append_ptarray(), ptarray_construct_empty(), ptarray_free(), and LWGEOM::type.

Referenced by geography_tree_shortestline(), LWGEOM_makeline(), and LWGEOM_makeline_garray().

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