Ejemplo n.º 1
0
Datum LWGEOM_from_text(PG_FUNCTION_ARGS)
{
	text *wkttext = PG_GETARG_TEXT_P(0);
	char *wkt = text2cstring(wkttext);
	LWGEOM_PARSER_RESULT lwg_parser_result;
	GSERIALIZED *geom_result = NULL;
	LWGEOM *lwgeom;

	POSTGIS_DEBUG(2, "LWGEOM_from_text");
	POSTGIS_DEBUGF(3, "wkt: [%s]", wkt);

	if (lwgeom_parse_wkt(&lwg_parser_result, wkt, LW_PARSER_CHECK_ALL) == LW_FAILURE)
		PG_PARSER_ERROR(lwg_parser_result);

	lwgeom = lwg_parser_result.geom;

	if ( lwgeom->srid != SRID_UNKNOWN )
	{
		elog(WARNING, "OGC WKT expected, EWKT provided - use GeomFromEWKT() for this");
	}

	/* read user-requested SRID if any */
	if ( PG_NARGS() > 1 ) 
		lwgeom_set_srid(lwgeom, PG_GETARG_INT32(1));

	geom_result = geometry_serialize(lwgeom);
	lwgeom_parser_result_free(&lwg_parser_result);

	PG_RETURN_POINTER(geom_result);
}
Datum line_from_encoded_polyline(PG_FUNCTION_ARGS)
{
  GSERIALIZED *geom;
  LWGEOM *lwgeom;
  text *encodedpolyline_input;
  char *encodedpolyline;
  int precision = 5;

  if (PG_ARGISNULL(0)) PG_RETURN_NULL();

  encodedpolyline_input = PG_GETARG_TEXT_P(0);
  encodedpolyline = text2cstring(encodedpolyline_input);

  if (PG_NARGS() >2 && !PG_ARGISNULL(2))
  {
    precision = PG_GETARG_INT32(2);
    if ( precision < 0 ) precision = 5;
  }

  lwgeom = lwgeom_from_encoded_polyline(encodedpolyline, precision);
  if ( ! lwgeom ) {
    /* Shouldn't get here */
    elog(ERROR, "lwgeom_from_encoded_polyline returned NULL");
    PG_RETURN_NULL();
  }
  lwgeom_set_srid(lwgeom, 4326);

  geom = geometry_serialize(lwgeom);
  lwgeom_free(lwgeom);
  PG_RETURN_POINTER(geom);
}
Ejemplo n.º 3
0
Datum point_from_geohash(PG_FUNCTION_ARGS)
{
	GBOX *box = NULL;
	LWPOINT *point = NULL;
	GSERIALIZED *result = NULL;
	text *geohash_input = NULL;
	char *geohash = NULL;
	double lon, lat;
	int precision = -1;

	if (PG_ARGISNULL(0))
	{
		PG_RETURN_NULL();
	}

	if (!PG_ARGISNULL(1))
	{
		precision = PG_GETARG_INT32(1);
	}

	geohash_input = PG_GETARG_TEXT_P(0);
	geohash = text2cstring(geohash_input);

	box = parse_geohash(geohash, precision);

	lon = box->xmin + (box->xmax - box->xmin) / 2;
	lat = box->ymin + (box->ymax - box->ymin) / 2;

	point = lwpoint_make2d(SRID_UNKNOWN, lon, lat);
	result = geometry_serialize((LWGEOM *) point);

	lwfree(box);

	PG_RETURN_POINTER(result);
}
Ejemplo n.º 4
0
Datum geography_from_text(PG_FUNCTION_ARGS)
{
	text *wkt_text = PG_GETARG_TEXT_P(0);
	/* Extract the cstring from the varlena */
	char *wkt = text2cstring(wkt_text);
	/* Pass the cstring to the input parser, and magic occurs! */
	Datum rv = DirectFunctionCall3(geography_in, PointerGetDatum(wkt), Int32GetDatum(0), Int32GetDatum(-1));
	/* Clean up and return */
	pfree(wkt);
	PG_RETURN_DATUM(rv);
}
Datum ST_RelateMatch(PG_FUNCTION_ARGS)
{
#if POSTGIS_GEOS_VERSION < 33
    lwerror("The GEOS version this postgis binary "
            "was compiled against (%d) doesn't support "
            "'ST_RelateMatch' function (3.3.0+ required)",
            POSTGIS_GEOS_VERSION);
    PG_RETURN_NULL();
#else /* POSTGIS_GEOS_VERSION >= 33 */

    char *mat, *pat;
    text *mat_text, *pat_text;
    int result;

    /* Read the arguments */
    mat_text = (PG_GETARG_TEXT_P(0));
    pat_text = (PG_GETARG_TEXT_P(1));

    /* Convert from text to cstring */
    mat = text2cstring(mat_text);
    pat = text2cstring(pat_text);

    initGEOS(lwnotice, lwgeom_geos_error);

    result = GEOSRelatePatternMatch(mat, pat);
    if (result == 2)
    {
        lwfree(mat);
        lwfree(pat);
        lwerror("GEOSRelatePatternMatch: %s", lwgeom_geos_errmsg);
        PG_RETURN_NULL();
    }

    lwfree(mat);
    lwfree(pat);
    PG_RETURN_BOOL(result);

#endif /* POSTGIS_GEOS_VERSION >= 33 */

}
Ejemplo n.º 6
0
Datum sfcgal_from_ewkt(PG_FUNCTION_ARGS)
{
	GSERIALIZED* result;
	sfcgal_prepared_geometry_t* g;
	text *wkttext = PG_GETARG_TEXT_P(0);
	char *cstring = text2cstring(wkttext);

	sfcgal_postgis_init();

	g = sfcgal_io_read_ewkt( cstring, strlen(cstring) );

	result = SFCGALPreparedGeometry2POSTGIS( g, 0 );
	sfcgal_prepared_geometry_delete( g );
	PG_RETURN_POINTER(result);
}
Ejemplo n.º 7
0
Datum parse_WKT_lwgeom(PG_FUNCTION_ARGS)
{
	text *wkt_text = PG_GETARG_TEXT_P(0);
	char *wkt;
	Datum result;

	/* Unwrap the PgSQL text type into a cstring */
	wkt = text2cstring(wkt_text); 
	
	/* Now we call over to the geometry_in function */
	result = DirectFunctionCall1(LWGEOM_in, CStringGetDatum(wkt));

	/* Return null on null */
	if ( ! result ) 
		PG_RETURN_NULL();

	PG_RETURN_DATUM(result);
}
Ejemplo n.º 8
0
Datum geography_from_binary(PG_FUNCTION_ARGS)
{
	char *wkb_cstring = NULL;
	text *wkb_hex = NULL;
	char *wkb_bytea = (char*)PG_DETOAST_DATUM(PG_GETARG_DATUM(0));
	char *hexarg = palloc(4 + VARHDRSZ);

	/* Create our second argument to binary_encode */
	SET_VARSIZE(hexarg, 4 + VARHDRSZ);
	memcpy(VARDATA(hexarg), "hex", 4);

	/* Convert the bytea into a hex representation cstring */
	wkb_hex = (text*)DatumGetPointer(DirectFunctionCall2(binary_encode, PointerGetDatum(wkb_bytea), PointerGetDatum(hexarg)));
	wkb_cstring = text2cstring(wkb_hex);
	pfree(hexarg);

	/* Pass the cstring to the input parser, and magic occurs! */
	PG_RETURN_DATUM(DirectFunctionCall3(geography_in, PointerGetDatum(wkb_cstring), Int32GetDatum(0), Int32GetDatum(-1)));
}
Ejemplo n.º 9
0
Datum geom_from_geojson(PG_FUNCTION_ARGS)
{
#ifndef HAVE_LIBJSON
	elog(ERROR, "You need JSON-C for ST_GeomFromGeoJSON");
	PG_RETURN_NULL();
#else /* HAVE_LIBJSON  */

	GSERIALIZED *geom;
	LWGEOM *lwgeom;
	text *geojson_input;
	char *geojson;
	char *srs = NULL;

	/* Get the geojson stream */
	if (PG_ARGISNULL(0)) 
		PG_RETURN_NULL();
	
	geojson_input = PG_GETARG_TEXT_P(0);
	geojson = text2cstring(geojson_input);

	lwgeom = lwgeom_from_geojson(geojson, &srs);
	if ( ! lwgeom ) 
	{
		/* Shouldn't get here */
		elog(ERROR, "lwgeom_from_geojson returned NULL");
		PG_RETURN_NULL();
	}

	if ( srs ) 
	{
		lwgeom_set_srid(lwgeom, getSRIDbySRS(srs));
		lwfree(srs);
	}

	geom = geometry_serialize(lwgeom);
	lwgeom_free(lwgeom);

	PG_RETURN_POINTER(geom);
#endif
}
Ejemplo n.º 10
0
Datum geography_from_text(PG_FUNCTION_ARGS)
{
	LWGEOM_PARSER_RESULT lwg_parser_result;
	GSERIALIZED *g_ser = NULL;
	text *wkt_text = PG_GETARG_TEXT_P(0);
	
	/* Extract the cstring from the varlena */
	char *wkt = text2cstring(wkt_text);

	/* Pass the cstring to the input parser, and magic occurs! */	
	if ( lwgeom_parse_wkt(&lwg_parser_result, wkt, LW_PARSER_CHECK_ALL) == LW_FAILURE )
		PG_PARSER_ERROR(lwg_parser_result);

	/* Clean up string */
	pfree(wkt);
	g_ser = gserialized_geography_from_lwgeom(lwg_parser_result.geom, -1);

	/* Clean up temporary object */
	lwgeom_free(lwg_parser_result.geom);

	PG_RETURN_POINTER(g_ser);
}
Ejemplo n.º 11
0
Datum box2d_from_geohash(PG_FUNCTION_ARGS)
{
	GBOX *box = NULL;
	text *geohash_input = NULL;
	char *geohash = NULL;
	int precision = -1;

	if (PG_ARGISNULL(0))
	{
		PG_RETURN_NULL();
	}

	if (!PG_ARGISNULL(1))
	{
		precision = PG_GETARG_INT32(1);
	}

	geohash_input = PG_GETARG_TEXT_P(0);
	geohash = text2cstring(geohash_input);

	box = parse_geohash(geohash, precision);

	PG_RETURN_POINTER(box);
}
Ejemplo n.º 12
0
Datum geom_from_geojson(PG_FUNCTION_ARGS)
{
#ifndef HAVE_LIBJSON
	elog(ERROR, "You need JSON-C for ST_GeomFromGeoJSON");
	PG_RETURN_NULL();
#else /* HAVE_LIBJSON  */

	GSERIALIZED *geom;
	LWGEOM *lwgeom;
	text *geojson_input;
	int geojson_size;
	char *geojson;
	int root_srid=0;
	bool hasz=true;
	json_tokener* jstok = NULL;
	json_object* poObj = NULL;
	json_object* poObjSrs = NULL;

	/* Get the geojson stream */
	if (PG_ARGISNULL(0)) PG_RETURN_NULL();
	geojson_input = PG_GETARG_TEXT_P(0);
	geojson = text2cstring(geojson_input);
	geojson_size = VARSIZE(geojson_input) - VARHDRSZ;

	/* Begin to Parse json */
	jstok = json_tokener_new();
	poObj = json_tokener_parse_ex(jstok, geojson, -1);
	if( jstok->err != json_tokener_success)
	{
		char err[256];
		snprintf(err, 256, "%s (at offset %d)", json_tokener_errors[jstok->err], jstok->char_offset);
		json_tokener_free(jstok);
		geojson_lwerror(err, 1);
	}
	json_tokener_free(jstok);

	poObjSrs = findMemberByName( poObj, "crs" );
	if (poObjSrs != NULL)
	{
		json_object* poObjSrsType = findMemberByName( poObjSrs, "type" );
		if (poObjSrsType != NULL)
		{
			json_object* poObjSrsProps = findMemberByName( poObjSrs, "properties" );
			json_object* poNameURL = findMemberByName( poObjSrsProps, "name" );
			const char* pszName = json_object_get_string( poNameURL );
			root_srid = getSRIDbySRS(pszName);
			POSTGIS_DEBUGF(3, "getSRIDbySRS returned root_srid = %d.", root_srid );
		}
	}

	lwgeom = parse_geojson(poObj, &hasz, &root_srid);

	lwgeom_add_bbox(lwgeom);
	if (root_srid && lwgeom->srid == -1) lwgeom->srid = root_srid;

	if (!hasz)
	{
		LWGEOM *tmp = lwgeom_force_2d(lwgeom);
		lwgeom_free(lwgeom);
		lwgeom = tmp;

		POSTGIS_DEBUG(2, "geom_from_geojson called.");
	}

	geom = geometry_serialize(lwgeom);
	lwgeom_free(lwgeom);

	PG_RETURN_POINTER(geom);
#endif
}
Ejemplo n.º 13
0
Datum geom_from_kml(PG_FUNCTION_ARGS)
{
	GSERIALIZED *geom;
	LWGEOM *lwgeom, *hlwgeom;
	xmlDocPtr xmldoc;
	text *xml_input;
	int xml_size;
	char *xml;
	bool hasz=true;
	xmlNodePtr xmlroot=NULL;


	/* Get the KML stream */
	if (PG_ARGISNULL(0)) PG_RETURN_NULL();
	xml_input = PG_GETARG_TEXT_P(0);
	xml = text2cstring(xml_input);
	xml_size = VARSIZE(xml_input) - VARHDRSZ;

	/* Begin to Parse XML doc */
	xmlInitParser();
	xmldoc = xmlParseMemory(xml, xml_size);
	if (!xmldoc || (xmlroot = xmlDocGetRootElement(xmldoc)) == NULL)
	{
		xmlFreeDoc(xmldoc);
		xmlCleanupParser();
		lwerror("invalid KML representation");
	}

	lwgeom = parse_kml(xmlroot, &hasz);

	/* Homogenize geometry result if needed */
	if (lwgeom->type == COLLECTIONTYPE)
	{
		hlwgeom = lwgeom_homogenize(lwgeom);
		lwgeom_release(lwgeom);
		lwgeom = hlwgeom;
	}

	lwgeom_add_bbox(lwgeom);

	/* KML geometries could be either 2 or 3D
	 *
	 * So we deal with 3D in all structures allocation, and flag hasz
	 * to false if we met once a missing Z dimension
	 * In this case, we force recursive 2D.
	 */
	if (!hasz)
	{
		LWGEOM *tmp = lwgeom_force_2d(lwgeom);
		lwgeom_free(lwgeom);
		lwgeom = tmp;
	}

	geom = geometry_serialize(lwgeom);
	lwgeom_free(lwgeom);

	xmlFreeDoc(xmldoc);
	xmlCleanupParser();

	PG_RETURN_POINTER(geom);
}
Ejemplo n.º 14
0
Datum LWGEOM_to_latlon(PG_FUNCTION_ARGS)
{
	/* Get the parameters */
	GSERIALIZED *pg_lwgeom = (GSERIALIZED *) PG_DETOAST_DATUM(PG_GETARG_DATUM(0));
	text *format_text = PG_GETARG_TEXT_P(1);

	LWGEOM *lwgeom;
	char *format_str = NULL;

	char * formatted_str;
	text * formatted_text;
	char * tmp;

	/* Only supports points. */
	uint8_t geom_type = gserialized_get_type(pg_lwgeom);
	if (POINTTYPE != geom_type)
	{
		lwerror("Only points are supported, you tried type %s.", lwtype_name(geom_type));
	}
	/* Convert to LWGEOM type */
	lwgeom = lwgeom_from_gserialized(pg_lwgeom);

  if (format_text == NULL) {
    lwerror("ST_AsLatLonText: invalid format string (null");
    PG_RETURN_NULL();
  }

	format_str = text2cstring(format_text);
  assert(format_str != NULL);

  /* The input string supposedly will be in the database encoding,
     so convert to UTF-8. */
  tmp = (char *)pg_do_encoding_conversion(
    (uint8_t *)format_str, strlen(format_str), GetDatabaseEncoding(), PG_UTF8);
  assert(tmp != NULL);
  if ( tmp != format_str ) {
    pfree(format_str);
    format_str = tmp;
  }

	/* Produce the formatted string. */
	formatted_str = lwpoint_to_latlon((LWPOINT *)lwgeom, format_str);
  assert(formatted_str != NULL);
  pfree(format_str);

  /* Convert the formatted string from UTF-8 back to database encoding. */
  tmp = (char *)pg_do_encoding_conversion(
    (uint8_t *)formatted_str, strlen(formatted_str),
    PG_UTF8, GetDatabaseEncoding());
  assert(tmp != NULL);
  if ( tmp != formatted_str) {
    pfree(formatted_str);
    formatted_str = tmp;
  }

	/* Convert to the postgres output string type. */
	formatted_text = cstring2text(formatted_str);
  pfree(formatted_str);

	PG_RETURN_POINTER(formatted_text);
}
Ejemplo n.º 15
0
Datum transform_geom(PG_FUNCTION_ARGS)
{
	GSERIALIZED *geom;
	GSERIALIZED *result=NULL;
	LWGEOM *lwgeom;
	projPJ input_pj, output_pj;
	char *input_proj4, *output_proj4;
	text *input_proj4_text;
	text *output_proj4_text;
	int32 result_srid ;
	char *pj_errstr;



	result_srid = PG_GETARG_INT32(3);
	if (result_srid == SRID_UNKNOWN)
	{
		elog(ERROR,"tranform: destination SRID = %d",SRID_UNKNOWN);
		PG_RETURN_NULL();
	}

	geom = (GSERIALIZED *)PG_DETOAST_DATUM_COPY(PG_GETARG_DATUM(0));
	if (gserialized_get_srid(geom) == SRID_UNKNOWN)
	{
		pfree(geom);
		elog(ERROR,"transform_geom: source SRID = %d",SRID_UNKNOWN);
		PG_RETURN_NULL();
	}

	/* Set the search path if we haven't already */
	SetPROJ4LibPath();

	/* Read the arguments */
	input_proj4_text  = (PG_GETARG_TEXT_P(1));
	output_proj4_text = (PG_GETARG_TEXT_P(2));

	/* Convert from text to cstring for libproj */
	input_proj4 = text2cstring(input_proj4_text);
	output_proj4 = text2cstring(output_proj4_text);

	/* make input and output projection objects */
	input_pj = lwproj_from_string(input_proj4);
	if ( input_pj == NULL )
	{
		pj_errstr = pj_strerrno(*pj_get_errno_ref());
		if ( ! pj_errstr ) pj_errstr = "";

		/* we need this for error reporting */
		/* pfree(input_proj4); */
		pfree(output_proj4);
		pfree(geom);
		
		elog(ERROR,
		    "transform_geom: could not parse proj4 string '%s' %s",
		    input_proj4, pj_errstr);
		PG_RETURN_NULL();
	}
	pfree(input_proj4);

	output_pj = lwproj_from_string(output_proj4);

	if ( output_pj == NULL )
	{
		pj_errstr = pj_strerrno(*pj_get_errno_ref());
		if ( ! pj_errstr ) pj_errstr = "";

		/* we need this for error reporting */
		/* pfree(output_proj4); */
		pj_free(input_pj);
		pfree(geom);

		elog(ERROR,
			"transform_geom: couldn't parse proj4 output string: '%s': %s",
			output_proj4, pj_errstr);
		PG_RETURN_NULL();
	}
	pfree(output_proj4);

	/* now we have a geometry, and input/output PJ structs. */
	lwgeom = lwgeom_from_gserialized(geom);
	lwgeom_transform(lwgeom, input_pj, output_pj);
	lwgeom->srid = result_srid;

	/* clean up */
	pj_free(input_pj);
	pj_free(output_pj);

	/* Re-compute bbox if input had one (COMPUTE_BBOX TAINTING) */
	if ( lwgeom->bbox )
	{
		lwgeom_drop_bbox(lwgeom);
		lwgeom_add_bbox(lwgeom);
	}

	result = geometry_serialize(lwgeom);

	lwgeom_free(lwgeom);
	PG_FREE_IF_COPY(geom, 0);

	PG_RETURN_POINTER(result); /* new geometry */
}
Ejemplo n.º 16
0
Datum geometry_estimated_extent(PG_FUNCTION_ARGS)
{
	text *txnsp = NULL;
	text *txtbl = NULL;
	text *txcol = NULL;
	char *nsp = NULL;
	char *tbl = NULL;
	char *col = NULL;
	char *query;
	ArrayType *array = NULL;
	int SPIcode;
	SPITupleTable *tuptable;
	TupleDesc tupdesc ;
	HeapTuple tuple ;
	bool isnull;
	GBOX *box;
	size_t querysize;
	GEOM_STATS geomstats;
	float reltuples;
	Datum binval;

	if ( PG_NARGS() == 3 )
	{
		txnsp = PG_GETARG_TEXT_P(0);
		txtbl = PG_GETARG_TEXT_P(1);
		txcol = PG_GETARG_TEXT_P(2);
	}
	else if ( PG_NARGS() == 2 )
	{
		txtbl = PG_GETARG_TEXT_P(0);
		txcol = PG_GETARG_TEXT_P(1);
	}
	else
	{
		elog(ERROR, "estimated_extent() called with wrong number of arguments");
		PG_RETURN_NULL();
	}

	POSTGIS_DEBUG(2, "geomtery_estimated_extent called");

	/* Connect to SPI manager */
	SPIcode = SPI_connect();
	if (SPIcode != SPI_OK_CONNECT)
	{
		elog(ERROR, "geometry_estimated_extent: couldnt open a connection to SPI");
		PG_RETURN_NULL() ;
	}

	querysize = VARSIZE(txtbl)+VARSIZE(txcol)+516;

	if ( txnsp )
	{
		nsp = text2cstring(txnsp);
		querysize += VARSIZE(txnsp);
	}
	else
	{
		querysize += 32; /* current_schema() */
	}

	tbl = text2cstring(txtbl);
	col = text2cstring(txcol);

#if POSTGIS_DEBUG_LEVEL > 0
	if ( txnsp )
	{
		POSTGIS_DEBUGF(3, " schema:%s table:%s column:%s", nsp, tbl, col);
	}
	else
	{
		POSTGIS_DEBUGF(3, " schema:current_schema() table:%s column:%s",
		               tbl, col);
	}
#endif

	query = palloc(querysize);


	/* Security check: because we access information in the pg_statistic table, we must run as the database
	superuser (by marking the function as SECURITY DEFINER) and check permissions ourselves */
	if ( txnsp )
	{
		sprintf(query, "SELECT has_table_privilege((SELECT usesysid FROM pg_user WHERE usename = session_user), '\"%s\".\"%s\"', 'select')", nsp, tbl);
	}
	else
	{
		sprintf(query, "SELECT has_table_privilege((SELECT usesysid FROM pg_user WHERE usename = session_user), '\"%s\"', 'select')", tbl);
	}

	POSTGIS_DEBUGF(4, "permission check sql query is: %s", query);

	SPIcode = SPI_exec(query, 1);
	if (SPIcode != SPI_OK_SELECT)
	{
		elog(ERROR, "geometry_estimated_extent: couldn't execute permission check sql via SPI");
		SPI_finish();
		PG_RETURN_NULL();
	}

	tuptable = SPI_tuptable;
	tupdesc = SPI_tuptable->tupdesc;
	tuple = tuptable->vals[0];

	if (!DatumGetBool(SPI_getbinval(tuple, tupdesc, 1, &isnull)))
	{
		elog(ERROR, "geometry_estimated_extent: permission denied for relation %s", tbl);
		SPI_finish();
		PG_RETURN_NULL();
	}


	/* Return the stats data */
	if ( txnsp )
	{
	  sprintf(query, 
	    "SELECT s.stanumbers1[5:8], c.reltuples FROM pg_class c"
	    " LEFT OUTER JOIN pg_namespace n ON (n.oid = c.relnamespace)"
	    " LEFT OUTER JOIN pg_attribute a ON (a.attrelid = c.oid )"
	    " LEFT OUTER JOIN pg_statistic s ON (s.starelid = c.oid AND "
	                                        "s.staattnum = a.attnum )"
	    " WHERE c.relname = '%s' AND a.attname = '%s' "
	    " AND n.nspname = '%s';",
	    tbl, col, nsp);
	}
	else
	{
	  sprintf(query, 
	    "SELECT s.stanumbers1[5:8], c.reltuples FROM pg_class c"
	    " LEFT OUTER JOIN pg_namespace n ON (n.oid = c.relnamespace)"
	    " LEFT OUTER JOIN pg_attribute a ON (a.attrelid = c.oid )"
	    " LEFT OUTER JOIN pg_statistic s ON (s.starelid = c.oid AND "
	                                        "s.staattnum = a.attnum )"
	    " WHERE c.relname = '%s' AND a.attname = '%s' "
	    " AND n.nspname = current_schema();",
	    tbl, col);
	}

	POSTGIS_DEBUGF(4, " query: %s", query);

	SPIcode = SPI_exec(query, 1);
	if (SPIcode != SPI_OK_SELECT )
	{
		elog(ERROR,"geometry_estimated_extent: couldnt execute sql via SPI");
		SPI_finish();
		PG_RETURN_NULL();
	}
	if (SPI_processed != 1)
	{

		POSTGIS_DEBUGF(3, " %d stat rows", SPI_processed);

		elog(ERROR, "Unexistent field \"%s\".\"%s\".\"%s\"",
			( nsp ? nsp : "<current>" ), tbl, col);

		SPI_finish();
		PG_RETURN_NULL() ;
	}

	tuptable = SPI_tuptable;
	tupdesc = SPI_tuptable->tupdesc;
	tuple = tuptable->vals[0];

	/* Check if the table has zero rows first */
	binval = SPI_getbinval(tuple, tupdesc, 2, &isnull);
	if (isnull)
	{

		POSTGIS_DEBUG(3, " reltuples is NULL");

		elog(ERROR, "geometry_estimated_extent: null reltuples for table");

		SPI_finish();
		PG_RETURN_NULL();
	}
	reltuples = DatumGetFloat4(binval);
	if ( ! reltuples )
	{
		POSTGIS_DEBUG(3, "table has estimated zero rows");

		/* 
		 * TODO: distinguish between empty and not analyzed ?
		 */
		elog(NOTICE, "\"%s\".\"%s\".\"%s\" is empty or not analyzed",
			( nsp ? nsp : "<current>" ), tbl, col);

		SPI_finish();
		PG_RETURN_NULL();
	}

	binval = SPI_getbinval(tuple, tupdesc, 1, &isnull);
	if (isnull)
	{

		POSTGIS_DEBUG(3, " stats are NULL");

		elog(ERROR, "geometry_estimated_extent: null statistics for table");

		SPI_finish();
		PG_RETURN_NULL();
	}
	array = DatumGetArrayTypeP(binval);
	if ( ArrayGetNItems(ARR_NDIM(array), ARR_DIMS(array)) != 4 )
	{
		elog(ERROR, " corrupted histogram");
		PG_RETURN_NULL();
	}

	POSTGIS_DEBUGF(3, " stats array has %d elems", ArrayGetNItems(ARR_NDIM(array), ARR_DIMS(array)));

	/*
	 * Construct GBOX.
	 * Must allocate this in upper executor context
	 * to keep it alive after SPI_finish().
	 */
	box = SPI_palloc(sizeof(GBOX));
	FLAGS_SET_GEODETIC(box->flags, 0);
	FLAGS_SET_Z(box->flags, 0);
	FLAGS_SET_M(box->flags, 0);

	/* Construct the box */
	memcpy(&(geomstats.xmin), ARR_DATA_PTR(array), sizeof(float)*4);
	box->xmin = geomstats.xmin;
	box->xmax = geomstats.xmax;
	box->ymin = geomstats.ymin;
	box->ymax = geomstats.ymax;

	POSTGIS_DEBUGF(3, " histogram extent = %g %g, %g %g", box->xmin,
	               box->ymin, box->xmax, box->ymax);

	SPIcode = SPI_finish();
	if (SPIcode != SPI_OK_FINISH )
	{
		elog(ERROR, "geometry_estimated_extent: couldn't disconnect from SPI");
	}

	/* TODO: enlarge the box by some factor */

	PG_RETURN_POINTER(box);
}