Refactor QLocationUtils NMEA support

Introduced an enum with currently supported NMEA sentences.
NMEA sentence detection factored out in a separate function.

Change-Id: Ib63f7bbedad51844c12b532f8d80988227e2f121
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>

2 files changed, 67 insertions, 32 deletions

diff --git a/src/positioning/qlocationutils.cpp b/src/positioning/qlocationutils.cpp
index 5304392b..f5062eb6 100644
--- a/src/positioning/qlocationutils.cpp
+++ b/src/positioning/qlocationutils.cpp
@@ -258,6 +258,32 @@ static void qlocationutils_readZda(const char *data, int size, QGeoPositionInfo
     info->setTimestamp(QDateTime(date, time, Qt::UTC));
 }
 
+QLocationUtils::NmeaSentence QLocationUtils::getNmeaSentenceType(const char *data, int size)
+{
+    if (size < 6 || data[0] != '$' || !hasValidNmeaChecksum(data, size))
+        return NmeaSentenceInvalid;
+
+    if (data[3] == 'G' && data[4] == 'G' && data[5] == 'A')
+        return NmeaSentenceGGA;
+
+    if (data[3] == 'G' && data[4] == 'S' && data[5] == 'A')
+        return NmeaSentenceGSA;
+
+    if (data[3] == 'G' && data[4] == 'L' && data[5] == 'L')
+        return NmeaSentenceGLL;
+
+    if (data[3] == 'R' && data[4] == 'M' && data[5] == 'C')
+        return NmeaSentenceRMC;
+
+    if (data[3] == 'V' && data[4] == 'T' && data[5] == 'G')
+        return NmeaSentenceVTG;
+
+    if (data[3] == 'Z' && data[4] == 'D' && data[5] == 'A')
+        return NmeaSentenceZDA;
+
+    return NmeaSentenceInvalid;
+}
+
 bool QLocationUtils::getPosInfoFromNmea(const char *data, int size, QGeoPositionInfo *info,
                                         double uere, bool *hasFix)
 {
@@ -266,7 +292,9 @@ bool QLocationUtils::getPosInfoFromNmea(const char *data, int size, QGeoPosition
 
     if (hasFix)
         *hasFix = false;
-    if (size < 6 || data[0] != '$' || !hasValidNmeaChecksum(data, size))
+
+    NmeaSentence nmeaType = getNmeaSentenceType(data, size);
+    if (nmeaType == NmeaSentenceInvalid)
         return false;
 
     // Adjust size so that * and following characters are not parsed by the following functions.
@@ -277,43 +305,28 @@ bool QLocationUtils::getPosInfoFromNmea(const char *data, int size, QGeoPosition
         }
     }
 
-    if (data[3] == 'G' && data[4] == 'G' && data[5] == 'A') {
-        // "$--GGA" sentence.
+    switch (nmeaType) {
+    case NmeaSentenceGGA:
         qlocationutils_readGga(data, size, info, uere, hasFix);
         return true;
-    }
-
-    if (data[3] == 'G' && data[4] == 'S' && data[5] == 'A') {
-        // "$--GSA" sentence.
+    case NmeaSentenceGSA:
         qlocationutils_readGsa(data, size, info, uere, hasFix);
         return true;
-    }
-
-    if (data[3] == 'G' && data[4] == 'L' && data[5] == 'L') {
-        // "$--GLL" sentence.
+    case NmeaSentenceGLL:
         qlocationutils_readGll(data, size, info, hasFix);
         return true;
-    }
-
-    if (data[3] == 'R' && data[4] == 'M' && data[5] == 'C') {
-        // "$--RMC" sentence.
+    case NmeaSentenceRMC:
         qlocationutils_readRmc(data, size, info, hasFix);
         return true;
-    }
-
-    if (data[3] == 'V' && data[4] == 'T' && data[5] == 'G') {
-        // "$--VTG" sentence.
+    case NmeaSentenceVTG:
         qlocationutils_readVtg(data, size, info, hasFix);
         return true;
-    }
-
-    if (data[3] == 'Z' && data[4] == 'D' && data[5] == 'A') {
-        // "$--ZDA" sentence.
+    case NmeaSentenceZDA:
         qlocationutils_readZda(data, size, info, hasFix);
         return true;
+    default:
+        return false;
     }
-
-    return false;
 }
 
 bool QLocationUtils::hasValidNmeaChecksum(const char *data, int size)
diff --git a/src/positioning/qlocationutils_p.h b/src/positioning/qlocationutils_p.h
index 69cf0fee..d9e6524a 100644
--- a/src/positioning/qlocationutils_p.h
+++ b/src/positioning/qlocationutils_p.h
@@ -54,6 +54,7 @@
 #include <math.h> // needed for non-std:: versions of functions
 #include <qmath.h>
 #include <QtPositioning/QGeoCoordinate>
+#include <QtPositioning/private/qpositioningglobal_p.h>
 
 static const double offsetEpsilon = 1e-12; // = 0.000000000001
 static const double leftOffset = -180.0 + offsetEpsilon;
@@ -64,7 +65,7 @@ class QTime;
 class QByteArray;
 
 class QGeoPositionInfo;
-class QLocationUtils
+class Q_POSITIONING_PRIVATE_EXPORT QLocationUtils
 {
 public:
     enum CardinalDirection {
@@ -86,6 +87,16 @@ public:
         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
+    };
+
     inline static bool isValidLat(double lat) {
         return lat >= -90.0 && lat <= 90.0;
     }
@@ -246,6 +257,11 @@ public:
     }
 
     /*
+        returns the NMEA sentence type.
+    */
+    static NmeaSentence getNmeaSentenceType(const char *data, int size);
+
+    /*
         Creates a QGeoPositionInfo from a GGA, GLL, RMC, VTG or ZDA sentence.
 
         Note:
@@ -254,25 +270,31 @@ public:
         - RMC reports date with a two-digit year so in this case the year
           is assumed to be after the year 2000.
     */
-    Q_AUTOTEST_EXPORT static bool getPosInfoFromNmea(const char *data, int size,
-                                                     QGeoPositionInfo *info, double uere,
-                                                     bool *hasFix = 0);
+    static bool getPosInfoFromNmea(const char *data,
+                                   int size,
+                                   QGeoPositionInfo *info, double uere,
+                                   bool *hasFix = nullptr);
 
     /*
         Returns true if the given NMEA sentence has a valid checksum.
     */
-    Q_AUTOTEST_EXPORT static bool hasValidNmeaChecksum(const char *data, int size);
+    static bool hasValidNmeaChecksum(const char *data, int size);
 
     /*
         Returns time from a string in hhmmss or hhmmss.z+ format.
     */
-    Q_AUTOTEST_EXPORT static bool getNmeaTime(const QByteArray &bytes, QTime *time);
+    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().
     */
-    Q_AUTOTEST_EXPORT static bool getNmeaLatLong(const QByteArray &latString, char latDirection, const QByteArray &lngString, char lngDirection, double *lat, double *lon);
+    static bool getNmeaLatLong(const QByteArray &latString,
+                               char latDirection,
+                               const QByteArray &lngString,
+                               char lngDirection,
+                               double *lat,
+                               double *lon);
 };
 
 QT_END_NAMESPACE