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/*
* JtsBinaryParser.java
*
* Binary Parser for JTS - relies on org.postgis V1.0.0+ package.
*
* (C) 2005 Markus Schaber, [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.
*
* 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.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA or visit the web at
* http://www.gnu.org.
*
* $Id: ShapeBinaryParser.java 2077 2005-11-25 17:22:34Z mschaber $
*/
package org.postgis.java2d;
import java.awt.geom.GeneralPath;
import org.postgis.binary.ByteGetter;
import org.postgis.binary.ValueGetter;
import org.postgis.binary.ByteGetter.BinaryByteGetter;
import org.postgis.binary.ByteGetter.StringByteGetter;
/**
* Parse binary representation of geometries. Currently, only text rep (hexed)
* implementation is tested.
*
* 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 Markus Schaber, [email protected]
*
*/
public class ShapeBinaryParser {
/**
* 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.)
*
* @returns a potential SRID or -1 if not present
*/
public synchronized int parse(String value, GeneralPath path) {
StringByteGetter bytes = new ByteGetter.StringByteGetter(value);
return parseGeometry(valueGetterForEndian(bytes), path);
}
/**
* Parse a binary encoded geometry.
*
* Is synchronized to protect offset counter. (Unfortunately, Java does not
* have neither call by reference nor multiple return values.)
*
* @returns a potential SRID or -1 if not present
*/
public synchronized int parse(byte[] value, GeneralPath path) {
BinaryByteGetter bytes = new ByteGetter.BinaryByteGetter(value);
return parseGeometry(valueGetterForEndian(bytes), path);
}
/**
* Parse a geometry starting at offset.
*
* @param path
*/
protected int parseGeometry(ValueGetter data, GeneralPath path) {
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 = -1;
if (haveS) {
srid = data.getInt();
}
switch (realtype) {
case org.postgis.Geometry.POINT :
parsePoint(data, haveZ, haveM, path);
break;
case org.postgis.Geometry.LINESTRING :
parseLineString(data, haveZ, haveM, path);
break;
case org.postgis.Geometry.POLYGON :
parsePolygon(data, haveZ, haveM, path);
break;
case org.postgis.Geometry.MULTIPOINT :
parseMultiPoint(data, path);
break;
case org.postgis.Geometry.MULTILINESTRING :
parseMultiLineString(data, path);
break;
case org.postgis.Geometry.MULTIPOLYGON :
parseMultiPolygon(data, path);
break;
case org.postgis.Geometry.GEOMETRYCOLLECTION :
parseCollection(data, path);
break;
default :
throw new IllegalArgumentException("Unknown Geometry Type!");
}
return srid;
}
private void parsePoint(ValueGetter data, boolean haveZ, boolean haveM, GeneralPath path) {
path.moveTo((float) data.getDouble(), (float) data.getDouble());
path.closePath();
skipZM(data, haveZ, haveM);
}
private void skipZM(ValueGetter data, boolean haveZ, boolean haveM) {
if (haveZ) { // skip Z value
data.getDouble();
}
if (haveM) { // skip M value
data.getDouble();
}
}
/** Parse an Array of "full" Geometries */
private void parseGeometryArray(ValueGetter data, int count, GeneralPath path) {
for (int i = 0; i < count; i++) {
parseGeometry(data, path);
}
}
/**
* Parse an Array of "slim" Points (without endianness and type, part of
* LinearRing and Linestring, but not MultiPoint!
*
* @param haveZ
* @param haveM
*/
private void parseCS(ValueGetter data, boolean haveZ, boolean haveM, GeneralPath path) {
int count = data.getInt();
if (count > 0) {
path.moveTo((float) data.getDouble(), (float) data.getDouble());
skipZM(data, haveZ, haveM);
for (int i = 1; i < count; i++) {
path.lineTo((float) data.getDouble(), (float) data.getDouble());
skipZM(data, haveZ, haveM);
}
}
}
private void parseMultiPoint(ValueGetter data, GeneralPath path) {
parseGeometryArray(data, data.getInt(), path);
}
private void parseLineString(ValueGetter data, boolean haveZ, boolean haveM, GeneralPath path) {
parseCS(data, haveZ, haveM, path);
}
private void parseLinearRing(ValueGetter data, boolean haveZ, boolean haveM, GeneralPath path) {
parseCS(data, haveZ, haveM, path);
path.closePath();
}
private void parsePolygon(ValueGetter data, boolean haveZ, boolean haveM, GeneralPath path) {
int holecount = data.getInt() - 1;
// parse shell
parseLinearRing(data, haveZ, haveM, path);
// parse inner rings
for (int i = 0; i < holecount; i++) {
parseLinearRing(data, haveZ, haveM, path);
}
}
private void parseMultiLineString(ValueGetter data, GeneralPath path) {
int count = data.getInt();
parseGeometryArray(data, count, path);
}
private void parseMultiPolygon(ValueGetter data, GeneralPath path) {
int count = data.getInt();
parseGeometryArray(data, count, path);
}
private void parseCollection(ValueGetter data, GeneralPath path) {
int count = data.getInt();
parseGeometryArray(data, count, path);
}
}
