/*
This file is part of RouteConverter.
RouteConverter is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
RouteConverter 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with RouteConverter; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
Copyright (C) 2010 Christian Pesch. All Rights Reserved.
*/
package slash.navigation.simple;
import slash.navigation.base.*;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.util.ArrayList;
import java.util.List;
import static java.lang.System.currentTimeMillis;
import static slash.common.type.CompactCalendar.createDateFormat;
import static slash.navigation.base.RouteCharacteristics.Track;
/**
* Reads garbled Navilink (.sbp) files.
*
* @author Malte Neumann
*/
public class GarbleNavilinkFormat extends NavilinkFormat implements GarbleNavigationFormat {
private static final long MINIMUM_TIME_MILLISECONDS = 949427965809L; // 01.01.2000
public String getName() {
return "Navilink Garble (*" + getExtension() + ")";
}
protected boolean isTrackStart(ByteBuffer buffer) {
short bitFlags = buffer.get(30);
short reserved = buffer.get(31);
return ((bitFlags & 0x01) == 1) && (reserved == 0x14);
}
private int readOneByteFromInput(InputStream source, byte[] record) throws IOException {
System.arraycopy(record, 1, record, 0, record.length - 1);
return source.read(record, SBP_RECORD_LENGTH - 1, 1);
}
private boolean isValidPosition(Wgs84Position position, Wgs84Position previous) {
boolean valid = (position.getHdop() >= 0.0 &&
position.getHdop() < 10.0);
valid = valid && (position.getLatitude() >= -90.0 &&
position.getLatitude() <= 90.0);
valid = valid && (position.getLongitude() >= -180.0 &&
position.getLatitude() <= 180.0);
valid = valid && (position.getElevation() > -100.0 &&
position.getElevation() < 14000.0);
valid = valid && (position.getSpeed() >= 0.0 &&
position.getSpeed() < 1200.0);
valid = valid && (position.getHeading() >= 0.0 &&
position.getHeading() <= 360.0);
valid = valid && (position.getTime().getTimeInMillis() > MINIMUM_TIME_MILLISECONDS &&
position.getTime().getTimeInMillis() < currentTimeMillis());
if (previous != null) {
// valid = valid && (position.getTime().getTimeInMillis() > previous.getTime().getTimeInMillis());
// would ignore too much points, thus I've build an after read check function
Double speed = position.calculateSpeed(previous);
if (speed != null)
valid = valid && (speed < 1200.0);
}
return valid;
}
private void deleteLogicalWrongPositionsInList(List<Wgs84Position> positions) {
int i = 1;
while (i < positions.size() - 1) {
Wgs84Position prev = positions.get(i - 1);
Wgs84Position actual = positions.get(i);
Wgs84Position next = positions.get(i + 1);
if (prev.getTime().getTimeInMillis() < actual.getTime().getTimeInMillis() &&
actual.getTime().getTimeInMillis() < next.getTime().getTimeInMillis())
i++;
else
positions.remove(i);
}
}
private void deleteLogicalWrongPositions(List<Wgs84Route> routeList) {
for (Wgs84Route route : routeList) {
deleteLogicalWrongPositionsInList(route.getPositions());
}
}
public void read(InputStream source, ParserContext<Wgs84Route> context) throws Exception {
byte[] record = new byte[SBP_RECORD_LENGTH];
ByteBuffer sbpRecordByteBuffer = ByteBuffer.wrap(record);
sbpRecordByteBuffer.order(ByteOrder.LITTLE_ENDIAN);
List<Wgs84Route> result = new ArrayList<>();
Wgs84Route activeRoute = null;
Wgs84Position position;
Wgs84Position previousPosition = null;
int readBytes = 0, pointCount = 0;
while (source.read(record) == SBP_RECORD_LENGTH) {
readBytes += SBP_RECORD_LENGTH;
do {
sbpRecordByteBuffer.position(0);
position = decodePosition(sbpRecordByteBuffer);
if (!isValidPosition(position, previousPosition)) {
position = null;
int count = readOneByteFromInput(source, record);
readBytes += count;
if (count != 1) {
break;
}
// the first position must inside the first 40 bytes
if (pointCount == 0 && readBytes > 40)
break;
}
} while (position == null);
// at least three positions in the first 100 bytes
if (readBytes > 100 && pointCount < 3)
return;
if ((activeRoute == null || isTrackStart(sbpRecordByteBuffer)) && position != null) {
activeRoute = createRoute(Track,
createDateFormat(TRACK_NAME_DATE_FORMAT).format(position.getTime().getTime()),
new ArrayList<BaseNavigationPosition>());
result.add(activeRoute);
}
if (position != null && activeRoute != null)
activeRoute.getPositions().add(position);
else {
context.appendRoutes(result);
return;
}
pointCount++;
previousPosition = position;
}
deleteLogicalWrongPositions(result);
// it must be 95% of the file valid
int minCorrectPositions = (int) (readBytes / (double) SBP_RECORD_LENGTH * 0.95);
if (pointCount < minCorrectPositions)
return;
context.appendRoutes(result);
}
}