radar-wp/vendor/phayes/geophp/lib/adapters/WKB.class.php
2015-02-24 16:25:12 +01:00

250 lines
6.4 KiB
PHP

<?php
/*
* (c) Patrick Hayes
*
* This code is open-source and licenced under the Modified BSD License.
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
/**
* PHP Geometry/WKB encoder/decoder
*
*/
class WKB extends GeoAdapter
{
private $dimension = 2;
private $z = FALSE;
private $m = FALSE;
/**
* Read WKB into geometry objects
*
* @param string $wkb
* Well-known-binary string
* @param bool $is_hex_string
* If this is a hexedecimal string that is in need of packing
*
* @return Geometry
*/
public function read($wkb, $is_hex_string = FALSE) {
if ($is_hex_string) {
$wkb = pack('H*',$wkb);
}
if (empty($wkb)) {
throw new Exception('Cannot read empty WKB geometry. Found ' . gettype($wkb));
}
$mem = fopen('php://memory', 'r+');
fwrite($mem, $wkb);
fseek($mem, 0);
$geometry = $this->getGeometry($mem);
fclose($mem);
return $geometry;
}
function getGeometry(&$mem) {
$base_info = unpack("corder/ctype/cz/cm/cs", fread($mem, 5));
if ($base_info['order'] !== 1) {
throw new Exception('Only NDR (little endian) SKB format is supported at the moment');
}
if ($base_info['z']) {
$this->dimension++;
$this->z = TRUE;
}
if ($base_info['m']) {
$this->dimension++;
$this->m = TRUE;
}
// If there is SRID information, ignore it - use EWKB Adapter to get SRID support
if ($base_info['s']) {
fread($mem, 4);
}
switch ($base_info['type']) {
case 1:
return $this->getPoint($mem);
case 2:
return $this->getLinstring($mem);
case 3:
return $this->getPolygon($mem);
case 4:
return $this->getMulti($mem,'point');
case 5:
return $this->getMulti($mem,'line');
case 6:
return $this->getMulti($mem,'polygon');
case 7:
return $this->getMulti($mem,'geometry');
}
}
function getPoint(&$mem) {
$point_coords = unpack("d*", fread($mem,$this->dimension*8));
if (!empty($point_coords)) {
return new Point($point_coords[1],$point_coords[2]);
}
else {
return new Point(); // EMPTY point
}
}
function getLinstring(&$mem) {
// Get the number of points expected in this string out of the first 4 bytes
$line_length = unpack('L',fread($mem,4));
// Return an empty linestring if there is no line-length
if (!$line_length[1]) return new LineString();
// Read the nubmer of points x2 (each point is two coords) into decimal-floats
$line_coords = unpack('d*', fread($mem,$line_length[1]*$this->dimension*8));
// We have our coords, build up the linestring
$components = array();
$i = 1;
$num_coords = count($line_coords);
while ($i <= $num_coords) {
$components[] = new Point($line_coords[$i],$line_coords[$i+1]);
$i += 2;
}
return new LineString($components);
}
function getPolygon(&$mem) {
// Get the number of linestring expected in this poly out of the first 4 bytes
$poly_length = unpack('L',fread($mem,4));
$components = array();
$i = 1;
while ($i <= $poly_length[1]) {
$components[] = $this->getLinstring($mem);
$i++;
}
return new Polygon($components);
}
function getMulti(&$mem, $type) {
// Get the number of items expected in this multi out of the first 4 bytes
$multi_length = unpack('L',fread($mem,4));
$components = array();
$i = 1;
while ($i <= $multi_length[1]) {
$components[] = $this->getGeometry($mem);
$i++;
}
switch ($type) {
case 'point':
return new MultiPoint($components);
case 'line':
return new MultiLineString($components);
case 'polygon':
return new MultiPolygon($components);
case 'geometry':
return new GeometryCollection($components);
}
}
/**
* Serialize geometries into WKB string.
*
* @param Geometry $geometry
*
* @return string The WKB string representation of the input geometries
*/
public function write(Geometry $geometry, $write_as_hex = FALSE) {
// We always write into NDR (little endian)
$wkb = pack('c',1);
switch ($geometry->getGeomType()) {
case 'Point';
$wkb .= pack('L',1);
$wkb .= $this->writePoint($geometry);
break;
case 'LineString';
$wkb .= pack('L',2);
$wkb .= $this->writeLineString($geometry);
break;
case 'Polygon';
$wkb .= pack('L',3);
$wkb .= $this->writePolygon($geometry);
break;
case 'MultiPoint';
$wkb .= pack('L',4);
$wkb .= $this->writeMulti($geometry);
break;
case 'MultiLineString';
$wkb .= pack('L',5);
$wkb .= $this->writeMulti($geometry);
break;
case 'MultiPolygon';
$wkb .= pack('L',6);
$wkb .= $this->writeMulti($geometry);
break;
case 'GeometryCollection';
$wkb .= pack('L',7);
$wkb .= $this->writeMulti($geometry);
break;
}
if ($write_as_hex) {
$unpacked = unpack('H*',$wkb);
return $unpacked[1];
}
else {
return $wkb;
}
}
function writePoint($point) {
// Set the coords
if (!$point->isEmpty()) {
$wkb = pack('dd',$point->x(), $point->y());
return $wkb;
} else {
return '';
}
}
function writeLineString($line) {
// Set the number of points in this line
$wkb = pack('L',$line->numPoints());
// Set the coords
foreach ($line->getComponents() as $point) {
$wkb .= pack('dd',$point->x(), $point->y());
}
return $wkb;
}
function writePolygon($poly) {
// Set the number of lines in this poly
$wkb = pack('L',$poly->numGeometries());
// Write the lines
foreach ($poly->getComponents() as $line) {
$wkb .= $this->writeLineString($line);
}
return $wkb;
}
function writeMulti($geometry) {
// Set the number of components
$wkb = pack('L',$geometry->numGeometries());
// Write the components
foreach ($geometry->getComponents() as $component) {
$wkb .= $this->write($component);
}
return $wkb;
}
}