lwpoint_from_wkb_state()

static LWPOINT* lwpoint_from_wkb_state ( wkb_parse_state *  s )

static

POINT Read a WKB point, starting just after the endian byte, type number and optional srid number.

Advance the parse state forward appropriately. WKB point has just a set of doubles, with the quantity depending on the dimension of the point, so this looks like a special case of the above with only one point.

Definition at line 397 of file lwin_wkb.c.

{
        static uint32_t npoints = 1;
        POINTARRAY *pa = NULL;
        size_t pa_size;
        uint32_t ndims = 2;
        const POINT2D *pt;
 
        /* Count the dimensions. */
        if( s->has_z ) ndims++;
        if( s->has_m ) ndims++;
        pa_size = ndims * WKB_DOUBLE_SIZE;
 
        /* Does the data we want to read exist? */
        wkb_parse_state_check(s, pa_size);
 
        /* If we're in a native endianness, we can just copy the data directly! */
        if( ! s->swap_bytes )
        {
                pa = ptarray_construct_copy_data(s->has_z, s->has_m, npoints, (uint8_t*)s->pos);
                s->pos += pa_size;
        }
        /* Otherwise we have to read each double, separately */
        else
        {
                uint32_t i = 0;
                double *dlist;
                pa = ptarray_construct(s->has_z, s->has_m, npoints);
                dlist = (double*)(pa->serialized_pointlist);
                for( i = 0; i < ndims; i++ )
                {
                        dlist[i] = double_from_wkb_state(s);
                }
        }
 
        /* Check for POINT(NaN NaN) ==> POINT EMPTY */
        pt = getPoint2d_cp(pa, 0);
        if ( isnan(pt->x) && isnan(pt->y) )
        {
                ptarray_free(pa);
                return lwpoint_construct_empty(s->srid, s->has_z, s->has_m);
        }
        else
        {
                return lwpoint_construct(s->srid, NULL, pa);
        }
}

References double_from_wkb_state(), getPoint2d_cp(), lwpoint_construct(), lwpoint_construct_empty(), ptarray_construct(), ptarray_construct_copy_data(), ptarray_free(), s, POINTARRAY::serialized_pointlist, WKB_DOUBLE_SIZE, wkb_parse_state_check(), POINT2D::x, and POINT2D::y.

Referenced by lwgeom_from_wkb_state().

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