path: root/src/positioning/qlocationutils_p.h

// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#ifndef QLOCATIONUTILS_P_H
#define QLOCATIONUTILS_P_H

//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists purely as an
// implementation detail.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//

#include <QtCore/QtGlobal>
#include <math.h> // needed for non-std:: versions of functions
#include <qmath.h>
#include <QtPositioning/QGeoCoordinate>
#include <QtPositioning/QNmeaSatelliteInfoSource>
#include <QtPositioning/private/qpositioningglobal_p.h>

static const double offsetEpsilon = 1e-12; // = 0.000000000001
static const double leftOffset = -180.0 + offsetEpsilon;
static const double rightOffset = 180.0 - offsetEpsilon;

QT_BEGIN_NAMESPACE
class QTime;
class QByteArray;

class QGeoPositionInfo;
class QGeoSatelliteInfo;
class Q_POSITIONING_EXPORT QLocationUtils
{
public:
    enum CardinalDirection {
        CardinalN,
        CardinalE,
        CardinalS,
        CardinalW,
        CardinalNE,
        CardinalSE,
        CardinalSW,
        CardinalNW,
        CardinalNNE,
        CardinalENE,
        CardinalESE,
        CardinalSSE,
        CardinalSSW,
        CardinalWSW,
        CardinalWNW,
        CardinalNNW
    };

    enum NmeaSentence {
        NmeaSentenceInvalid,
        NmeaSentenceGGA, // Fix information
        NmeaSentenceGSA, // Overall Satellite data, such as HDOP and VDOP
        NmeaSentenceGLL, // Lat/Lon data
        NmeaSentenceRMC, // Recommended minimum data for gps
        NmeaSentenceVTG, // Vector track an Speed over the Ground
        NmeaSentenceZDA, // Date and Time
        NmeaSentenceGSV  // Per-Satellite Info
    };

    inline static bool isValidLat(double lat) {
        return lat >= -90.0 && lat <= 90.0;
    }
    inline static bool isValidLong(double lng) {
        return lng >= -180.0 && lng <= 180.0;
    }

    inline static double clipLat(double lat, double clipValue = 90.0) {
        if (lat > clipValue)
            lat = clipValue;
        else if (lat < -clipValue)
            lat = -clipValue;
        return lat;
    }

    inline static double wrapLong(double lng) {
        if (lng > 180.0)
            lng -= 360.0;
        else if (lng < -180.0)
            lng += 360.0;
        return lng;
    }

    inline static CardinalDirection azimuthToCardinalDirection4(double azimuth)
    {
        azimuth = fmod(azimuth, 360.0);
        if (azimuth < 45.0 || azimuth > 315.0 )
            return CardinalN;
        else if (azimuth < 135.0)
            return CardinalE;
        else if (azimuth < 225.0)
            return CardinalS;
        else
            return CardinalW;
    }

    inline static CardinalDirection azimuthToCardinalDirection8(double azimuth)
    {
        azimuth = fmod(azimuth, 360.0);
        if (azimuth < 22.5 || azimuth > 337.5 )
            return CardinalN;
        else if (azimuth < 67.5)
            return CardinalNE;
        else if (azimuth < 112.5)
            return CardinalE;
        else if (azimuth < 157.5)
            return CardinalSE;
        else if (azimuth < 202.5)
            return CardinalS;

        else if (azimuth < 247.5)
            return CardinalSW;
        else if (azimuth < 292.5)
            return CardinalW;
        else
            return CardinalNW;
    }

    inline static CardinalDirection azimuthToCardinalDirection16(double azimuth)
    {
        azimuth = fmod(azimuth, 360.0);
        if (azimuth < 11.5 || azimuth > 348.75 )
            return CardinalN;
        else if (azimuth < 33.75)
            return CardinalNNE;
        else if (azimuth < 56.25)
            return CardinalNE;
        else if (azimuth < 78.75)
            return CardinalENE;
        else if (azimuth < 101.25)
            return CardinalE;
        else if (azimuth < 123.75)
            return CardinalESE;
        else if (azimuth < 146.25)
            return CardinalSE;
        else if (azimuth < 168.75)
            return CardinalSSE;
        else if (azimuth < 191.25)
            return CardinalS;

        else if (azimuth < 213.75)
            return CardinalSSW;
        else if (azimuth < 236.25)
            return CardinalSW;
        else if (azimuth < 258.75)
            return CardinalWSW;
        else if (azimuth < 281.25)
            return CardinalW;
        else if (azimuth < 303.75)
            return CardinalWNW;
        else if (azimuth < 326.25)
            return CardinalNW;
        else
            return CardinalNNW;
    }

    // For values exceeding +- 720.0
    inline static double wrapLongExt(double lng) {
        double remainder = fmod(lng + 180.0, 360.0);
        return fmod(remainder + 360.0, 360.0) - 180.0;
    }

    // Mirrors the azimuth against the X axis. Azimuth assumed to be in [0,360[
    inline static double mirrorAzimuthX(double azimuth) {
        if (azimuth <= 90.0)
             return 180.0 - azimuth;
         else
             return 180.0 + (360.0 - azimuth);
    }

    // Mirrors the azimuth against the Y axis. Azimuth assumed to be in [0,360[
    inline static double mirrorAzimuthY(double azimuth) {
        if (azimuth == 0.0)
            return 0.0;
        return 360.0 - azimuth;
    }

    inline static double radians(double degrees)
    {
        return qDegreesToRadians(degrees);
    }

    inline static double degrees(double radians)
    {
        return qRadiansToDegrees(radians);
    }

    inline static double earthMeanRadius()
    {
        return 6371007.2;
    }

    inline static double earthMeanCircumference()
    {
        return earthMeanRadius() * 2.0 * M_PI;
    }

    inline static double mercatorMaxLatitude()
    {
        return 85.05113;
    }

    inline static QGeoCoordinate antipodalPoint(const QGeoCoordinate &p)
    {
        return QGeoCoordinate(-p.latitude(), wrapLong(p.longitude() + 180.0));
    }

    // Leftmost longitude before wrapping kicks in
    inline static double mapLeftLongitude(double centerLongitude)
    {
        return wrapLong(centerLongitude + leftOffset);
    }

    // Rightmost longitude before wrapping kicks in
    inline static double  mapRightLongitude(double centerLongitude)
    {
        return wrapLong(centerLongitude - leftOffset);
    }

    inline static void split_double(double input, float *hipart, float *lopart)
    {
        *hipart = (float) input;
        double delta = input - ((double) *hipart);
        *lopart = (float) delta;
    }

    static qreal metersPerPixel(qreal zoomLevel, const QGeoCoordinate &coordinate)
    {
        const qreal metersPerTile = earthMeanCircumference() * std::cos(radians(coordinate.latitude())) / std::pow(2, zoomLevel);
        return metersPerTile / 256.0;
    }

    /*
        returns the NMEA sentence type.
    */
    static NmeaSentence getNmeaSentenceType(QByteArrayView bv);

    /*
        Returns the satellite system type based on the message type.
        See https://gpsd.gitlab.io/gpsd/NMEA.html#_talker_ids for reference
    */
    static QGeoSatelliteInfo::SatelliteSystem getSatelliteSystem(QByteArrayView bv);

    /*
        Returns the satellite system type based on the satellite id.
        See https://gpsd.gitlab.io/gpsd/NMEA.html#_satellite_ids for reference
    */
    static QGeoSatelliteInfo::SatelliteSystem getSatelliteSystemBySatelliteId(int satId);

    /*
        Creates a QGeoPositionInfo from a GGA, GLL, RMC, VTG or ZDA sentence.

        Note:
        - GGA and GLL sentences have time but not date so the update's
          QDateTime object will have an invalid date.
        - RMC reports date with a two-digit year so in this case the year
          is assumed to be after the year 2000.
    */
    static bool getPosInfoFromNmea(QByteArrayView bv,
                                   QGeoPositionInfo *info, double uere,
                                   bool *hasFix = nullptr);

    /*
        Retruns a list of QGeoSatelliteInfo in the view.

        Note: this function has to be called repeatedly until it returns
        QNmeaSatelliteInfoSource::FullyParsed.
        Reason being that GSV sentences can be split into multiple samples, so
        getting the full data requires parsing multiple sentences.
     */
    static QNmeaSatelliteInfoSource::SatelliteInfoParseStatus
    getSatInfoFromNmea(QByteArrayView bv, QList<QGeoSatelliteInfo> &infos, QGeoSatelliteInfo::SatelliteSystem &system);

    /*
        Parses GSA for satellites in use.

        Returns satellite system type or QGeoSatelliteInfo::Undefined if parsing
        failed
     */
    static QGeoSatelliteInfo::SatelliteSystem getSatInUseFromNmea(QByteArrayView bv,
                                                                  QList<int> &pnrsInUse);

    /*
        Returns true if the given NMEA sentence has a valid checksum.
    */
    static bool hasValidNmeaChecksum(QByteArrayView bv);

    /*
        Returns time from a string in hhmmss or hhmmss.z+ format.
    */
    static bool getNmeaTime(const QByteArray &bytes, QTime *time);

    /*
        Accepts for example ("2734.7964", 'S', "15306.0124", 'E') and returns the
        lat-long values. Fails if lat or long fail isValidLat() or isValidLong().
    */
    static bool getNmeaLatLong(const QByteArray &latString,
                               char latDirection,
                               const QByteArray &lngString,
                               char lngDirection,
                               double *lat,
                               double *lon);
};

QT_END_NAMESPACE

#endif