ST_RemoveSmallParts()

Datum ST_RemoveSmallParts

(

PG_FUNCTION_ARGS

)

Definition at line 77 of file lwgeom_remove_small_parts.c.

                                            {
 
        double mindx = 0, mindy = 0;
        unsigned int i, j, iw, jw;
 
        GSERIALIZED *serialized_in;
        GSERIALIZED *serialized_out;
 
        LWGEOM *geom;
 
        // geom input check
        if (PG_GETARG_POINTER(0) == NULL) {
                PG_RETURN_NULL();
        }
 
        serialized_in = (GSERIALIZED *)PG_DETOAST_DATUM_COPY(PG_GETARG_DATUM(0));
 
        if (PG_NARGS() == 3) {
 
                if (PG_ARGISNULL(1) || PG_ARGISNULL(2)) {
                        // no valid args given, leave untouched
                        PG_RETURN_POINTER(serialized_in);
                }
 
                mindx = PG_GETARG_FLOAT8(1);
                mindy = PG_GETARG_FLOAT8(2);
                if (mindx <= 0 && mindy <= 0) {
                        // nothing to do
                        PG_RETURN_POINTER(serialized_in);
                }
 
                // type check (only polygon and line types are supported yet)
                if (gserialized_get_type(serialized_in) != POLYGONTYPE &&
                        gserialized_get_type(serialized_in) != MULTIPOLYGONTYPE &&
                        gserialized_get_type(serialized_in) != LINETYPE &&
                        gserialized_get_type(serialized_in) != MULTILINETYPE) {
 
                        // no (multi)polygon or (multi)linetype, leave untouched
                        PG_RETURN_POINTER(serialized_in);
                }
 
        }
 
        else {
                // unknown params, leave untouched
                PG_RETURN_POINTER(serialized_in);
        }
 
        // deserialize geom and copy coordinates (no clone_deep)
        geom = lwgeom_from_gserialized(serialized_in);
 
        if (geom->type == LINETYPE) {
 
                LWLINE* line = (LWLINE*)geom;
                ptarray_remove_dim_helper(line->points, mindx, mindy);
        }
 
        if (geom->type == MULTILINETYPE) {
 
                LWMLINE* mline = (LWMLINE*)geom;
                iw = 0;
                for (i=0; i<mline->ngeoms; i++) {
                        LWLINE* line = mline->geoms[i];
                        ptarray_remove_dim_helper(line->points, mindx, mindy);
 
                        if (line->points->npoints) {
                                // keep (reduced) line
                                mline->geoms[iw++] = line;
                        }
                        else {
                                // discard current line
                                lwfree(line);
                        }
                }
                mline->ngeoms = iw;
        }
 
        if (geom->type == POLYGONTYPE) {
 
                LWPOLY* polygon = (LWPOLY*)geom;
                iw = 0;
                for (i=0; i<polygon->nrings; i++) {
                        ptarray_remove_dim_helper(polygon->rings[i], mindx, mindy);
 
                        if (polygon->rings[i]->npoints) {
                                // keep (reduced) ring
                                polygon->rings[iw++] = polygon->rings[i];
                        }
                        else {
                                if (!i) {
                                        // exterior ring too small, free and skip all rings
                                        unsigned int k;
                                        for (k=0; k<polygon->nrings; k++) {
                                                lwfree(polygon->rings[k]);
                                        }
                                        break;
                                }
                                else {
                                        // free and remove current interior ring
                                        lwfree(polygon->rings[i]);
                                }
                        }
                }
                polygon->nrings = iw;
        }
 
        if (geom->type == MULTIPOLYGONTYPE) {
 
                LWMPOLY* mpolygon = (LWMPOLY*)geom;
                jw = 0;
                for (j=0; j<mpolygon->ngeoms; j++) {
 
                        LWPOLY* polygon = mpolygon->geoms[j];
                        iw = 0;
                        for (i=0; i<polygon->nrings; i++) {
                                ptarray_remove_dim_helper(polygon->rings[i], mindx, mindy);
 
                                if (polygon->rings[i]->npoints) {
                                        // keep (reduced) ring
                                        polygon->rings[iw++] = polygon->rings[i];
                                }
                                else {
                                        if (!i) {
                                                // exterior ring too small, free and skip all rings
                                                unsigned int k;
                                                for (k=0; k<polygon->nrings; k++) {
                                                        lwfree(polygon->rings[k]);
                                                }
                                                break;
                                        }
                                        else {
                                                // free and remove current interior ring
                                                lwfree(polygon->rings[i]);
                                        }
                                }
                        }
                        polygon->nrings = iw;
 
                        if (iw) {
                                mpolygon->geoms[jw++] = polygon;
                        }
                        else {
                                // free and remove polygon from multipolygon
                                lwfree(polygon);
                        }
                }
                mpolygon->ngeoms = jw;
        }
 
        // recompute bbox if computed previously (may result in NULL)
        lwgeom_drop_bbox(geom);
        lwgeom_add_bbox(geom);
 
        serialized_out = gserialized_from_lwgeom(geom, 0);
        lwgeom_free(geom);
 
        PG_FREE_IF_COPY(serialized_in, 0);
        PG_RETURN_POINTER(serialized_out);
}

References LWMLINE::geoms, LWMPOLY::geoms, gserialized_from_lwgeom(), gserialized_get_type(), LINETYPE, lwfree(), lwgeom_add_bbox(), lwgeom_drop_bbox(), lwgeom_free(), lwgeom_from_gserialized(), MULTILINETYPE, MULTIPOLYGONTYPE, LWMLINE::ngeoms, LWMPOLY::ngeoms, POINTARRAY::npoints, LWPOLY::nrings, LWLINE::points, POLYGONTYPE, ptarray_remove_dim_helper(), LWPOLY::rings, and LWGEOM::type.

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