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PostGIS adds support for geographic objects to the PostgreSQL object-relational database.
/*
* BinaryParser.java
*
* PostGIS extension for PostgreSQL JDBC driver - Binary Parser
*
* (C) 2005 Markus Schaber, [email protected]
*
* (C) 2015 Phillip Ross, [email protected]
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
package org.postgis.binary;
import org.postgis.Geometry;
import org.postgis.GeometryCollection;
import org.postgis.LineString;
import org.postgis.LinearRing;
import org.postgis.MultiLineString;
import org.postgis.MultiPoint;
import org.postgis.MultiPolygon;
import org.postgis.Point;
import org.postgis.Polygon;
import org.postgis.binary.ByteGetter.BinaryByteGetter;
import org.postgis.binary.ByteGetter.StringByteGetter;
/**
* Parse binary representation of geometries.
*
* It should be easy to add char[] and CharSequence ByteGetter instances,
* although the latter one is not compatible with older jdks.
*
* I did not implement real unsigned 32-bit integers or emulate them with long,
* as both java Arrays and Strings currently can have only 2^31-1 elements
* (bytes), so we cannot even get or build Geometries with more than approx.
* 2^28 coordinates (8 bytes each).
*
* @author {@literal Markus Schaber }
*
*/
public class BinaryParser {
/**
* Get the appropriate ValueGetter for my endianness
*
* @param bytes The appropriate Byte Getter
*
* @return the ValueGetter
*/
public static ValueGetter valueGetterForEndian(ByteGetter bytes) {
if (bytes.get(0) == ValueGetter.XDR.NUMBER) { // XDR
return new ValueGetter.XDR(bytes);
} else if (bytes.get(0) == ValueGetter.NDR.NUMBER) {
return new ValueGetter.NDR(bytes);
} else {
throw new IllegalArgumentException("Unknown Endian type:" + bytes.get(0));
}
}
/**
* Parse a hex encoded geometry
*
* Is synchronized to protect offset counter. (Unfortunately, Java does not
* have neither call by reference nor multiple return values.)
*
* @param value String containing the data to be parsed
* @return resulting geometry for the parsed data
*/
public synchronized Geometry parse(String value) {
StringByteGetter bytes = new ByteGetter.StringByteGetter(value);
return parseGeometry(valueGetterForEndian(bytes));
}
/**
* Parse a binary encoded geometry.
*
* Is synchronized to protect offset counter. (Unfortunately, Java does not
* have neither call by reference nor multiple return values.)
*
* @param value byte array containing the data to be parsed
* @return resulting geometry for the parsed data
*/
public synchronized Geometry parse(byte[] value) {
BinaryByteGetter bytes = new ByteGetter.BinaryByteGetter(value);
return parseGeometry(valueGetterForEndian(bytes));
}
/**
* Parse a geometry starting at offset.
*
* @param data ValueGetter with the data to be parsed
* @return the parsed geometry
* */
protected Geometry parseGeometry(ValueGetter data) {
byte endian = data.getByte(); // skip and test endian flag
if (endian != data.endian) {
throw new IllegalArgumentException("Endian inconsistency!");
}
int typeword = data.getInt();
int realtype = typeword & 0x1FFFFFFF; // cut off high flag bits
boolean haveZ = (typeword & 0x80000000) != 0;
boolean haveM = (typeword & 0x40000000) != 0;
boolean haveS = (typeword & 0x20000000) != 0;
int srid = Geometry.UNKNOWN_SRID;
if (haveS) {
srid = Geometry.parseSRID(data.getInt());
}
Geometry result1;
switch (realtype) {
case Geometry.POINT :
result1 = parsePoint(data, haveZ, haveM);
break;
case Geometry.LINESTRING :
result1 = parseLineString(data, haveZ, haveM);
break;
case Geometry.POLYGON :
result1 = parsePolygon(data, haveZ, haveM);
break;
case Geometry.MULTIPOINT :
result1 = parseMultiPoint(data);
break;
case Geometry.MULTILINESTRING :
result1 = parseMultiLineString(data);
break;
case Geometry.MULTIPOLYGON :
result1 = parseMultiPolygon(data);
break;
case Geometry.GEOMETRYCOLLECTION :
result1 = parseCollection(data);
break;
default :
throw new IllegalArgumentException("Unknown Geometry Type: " + realtype);
}
Geometry result = result1;
if (srid != Geometry.UNKNOWN_SRID) {
result.setSrid(srid);
}
return result;
}
private Point parsePoint(ValueGetter data, boolean haveZ, boolean haveM) {
double X = data.getDouble();
double Y = data.getDouble();
Point result;
if (haveZ) {
double Z = data.getDouble();
result = new Point(X, Y, Z);
} else {
result = new Point(X, Y);
}
if (haveM) {
result.setM(data.getDouble());
}
return result;
}
/** Parse an Array of "full" Geometries */
private void parseGeometryArray(ValueGetter data, Geometry[] container) {
for (int i = 0; i < container.length; i++) {
container[i] = parseGeometry(data);
}
}
/**
* Parse an Array of "slim" Points (without endianness and type, part of
* LinearRing and Linestring, but not MultiPoint!
*
* @param haveZ
* @param haveM
*/
private Point[] parsePointArray(ValueGetter data, boolean haveZ, boolean haveM) {
int count = data.getInt();
Point[] result = new Point[count];
for (int i = 0; i < count; i++) {
result[i] = parsePoint(data, haveZ, haveM);
}
return result;
}
private MultiPoint parseMultiPoint(ValueGetter data) {
Point[] points = new Point[data.getInt()];
parseGeometryArray(data, points);
return new MultiPoint(points);
}
private LineString parseLineString(ValueGetter data, boolean haveZ, boolean haveM) {
Point[] points = parsePointArray(data, haveZ, haveM);
return new LineString(points);
}
private LinearRing parseLinearRing(ValueGetter data, boolean haveZ, boolean haveM) {
Point[] points = parsePointArray(data, haveZ, haveM);
return new LinearRing(points);
}
private Polygon parsePolygon(ValueGetter data, boolean haveZ, boolean haveM) {
int count = data.getInt();
LinearRing[] rings = new LinearRing[count];
for (int i = 0; i < count; i++) {
rings[i] = parseLinearRing(data, haveZ, haveM);
}
return new Polygon(rings);
}
private MultiLineString parseMultiLineString(ValueGetter data) {
int count = data.getInt();
LineString[] strings = new LineString[count];
parseGeometryArray(data, strings);
return new MultiLineString(strings);
}
private MultiPolygon parseMultiPolygon(ValueGetter data) {
int count = data.getInt();
Polygon[] polys = new Polygon[count];
parseGeometryArray(data, polys);
return new MultiPolygon(polys);
}
private GeometryCollection parseCollection(ValueGetter data) {
int count = data.getInt();
Geometry[] geoms = new Geometry[count];
parseGeometryArray(data, geoms);
return new GeometryCollection(geoms);
}
}