parse_gml_curve()

static LWGEOM* parse_gml_curve ( xmlNodePtr  xnode, bool *  hasz, int *  root_srid  )

static

Parse GML Curve (3.1.1)

Definition at line 1135 of file lwgeom_in_gml.c.

{
        xmlNodePtr xa;
        size_t lss;
        bool found=false;
        gmlSrs srs;
        LWGEOM *geom=NULL;
        POINTARRAY *pa=NULL;
        POINTARRAY **ppa=NULL;
        uint32 npoints=0;
        xmlChar *interpolation=NULL;
 
        if (is_xlink(xnode)) xnode = get_xlink_node(xnode);
        if (xnode == NULL)
                gml_lwpgerror("invalid GML representation", 30);
 
        /* Looking for gml:segments */
        for (xa = xnode->children ; xa != NULL ; xa = xa->next)
        {
                if (xa->type != XML_ELEMENT_NODE) continue;
                if (!is_gml_namespace(xa, false)) continue;
                if (is_gml_element(xa, "segments"))
                {
                        found = true;
                        break;
                }
        }
        if (!found) gml_lwpgerror("invalid GML representation", 37);
 
        ppa = (POINTARRAY**) lwalloc(sizeof(POINTARRAY*));
 
        /* Processing each gml:LineStringSegment */
        for (xa = xa->children, lss=0; xa != NULL ; xa = xa->next)
        {
                if (xa->type != XML_ELEMENT_NODE) continue;
                if (!is_gml_namespace(xa, false)) continue;
 
                if (!is_gml_element(xa, "LineStringSegment")) continue;
 
                /* GML SF is restricted to linear interpolation  */
                interpolation = gmlGetProp(xa, "interpolation");
                if (interpolation != NULL)
                {
                        if (strcmp((char *) interpolation, "linear"))
                                gml_lwpgerror("invalid GML representation", 38);
                        xmlFree(interpolation);
                }
 
                if (lss > 0) ppa = (POINTARRAY**) lwrealloc((POINTARRAY *) ppa,
                                           sizeof(POINTARRAY*) * (lss + 1));
 
                ppa[lss] = parse_gml_data(xa->children, hasz, root_srid);
                npoints += ppa[lss]->npoints;
                if (ppa[lss]->npoints < 2)
                        gml_lwpgerror("invalid GML representation", 39);
                lss++;
        }
        if (lss == 0) gml_lwpgerror("invalid GML representation", 40);
 
        /* Most common case, a single segment */
        if (lss == 1) pa = ppa[0];
 
        if (lss > 1)
        {
                /*
                 * "The curve segments are connected to one another, with the end point
                 *  of each segment except the last being the start point of the next
                 *  segment"  from  ISO 19107:2003 -> 6.3.16.1 (p43)
                 *
                 * So we must aggregate all the segments into a single one and avoid
                 * to copy the redundant points
                 */
                size_t cp_point_size = sizeof(POINT3D); /* All internals are done with 3D */
                size_t final_point_size = *hasz ? sizeof(POINT3D) : sizeof(POINT2D);
                pa = ptarray_construct(1, 0, npoints - lss + 1);
 
                /* Copy the first linestring fully */
                memcpy(getPoint_internal(pa, 0), getPoint_internal(ppa[0], 0), cp_point_size * (ppa[0]->npoints));
                npoints = ppa[0]->npoints;
                lwfree(ppa[0]);
 
                /* For the rest of linestrings, ensure the first point matches the
                 * last point of the previous one, and copy all points except the
                 * first one (since it'd be repeated)
                 */
                for (size_t i = 1; i < lss; i++)
                {
                        if (memcmp(getPoint_internal(pa, npoints - 1), getPoint_internal(ppa[i], 0), final_point_size))
                                gml_lwpgerror("invalid GML representation", 41);
 
                        memcpy(getPoint_internal(pa, npoints),
                               getPoint_internal(ppa[i], 1),
                               cp_point_size * (ppa[i]->npoints - 1));
 
                        npoints += ppa[i]->npoints - 1;
                        lwfree(ppa[i]);
                }
        }
 
        lwfree(ppa);
 
        parse_gml_srs(xnode, &srs);
        if (srs.reverse_axis) pa = ptarray_flip_coordinates(pa);
        if (srs.srid != *root_srid && *root_srid != SRID_UNKNOWN)
                gml_reproject_pa(pa, srs.srid, *root_srid);
        geom = (LWGEOM *) lwline_construct(*root_srid, NULL, pa);
 
        return geom;
}

References get_xlink_node(), getPoint_internal(), gml_lwpgerror(), gml_reproject_pa(), gmlGetProp(), is_gml_element(), is_gml_namespace(), is_xlink(), lwalloc(), lwfree(), lwline_construct(), lwrealloc(), POINTARRAY::npoints, parse_gml_data(), parse_gml_srs(), ptarray_construct(), ptarray_flip_coordinates(), struct_gmlSrs::reverse_axis, struct_gmlSrs::srid, and SRID_UNKNOWN.

Referenced by parse_gml().

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