Add hash function for QGeoCoordinate

[ChangeLog][QtPositioning][General] Added qHash(QGeoCoordinate()).

Task-number: QTBUG-51404
Change-Id: I02c6dc0a5399ebf3181b34ffa58a82a2119118a0
Reviewed-by: Paolo Angelelli <paolo.angelelli@theqtcompany.com>
Reviewed-by: Michal Klocek <michal.klocek@theqtcompany.com>

3 files changed, 59 insertions, 0 deletions

diff --git a/src/positioning/qgeocoordinate.cpp b/src/positioning/qgeocoordinate.cpp
index c71422ca..f28e1865 100644
--- a/src/positioning/qgeocoordinate.cpp
+++ b/src/positioning/qgeocoordinate.cpp
@@ -762,4 +762,21 @@ QDataStream &operator>>(QDataStream &stream, QGeoCoordinate &coordinate)
 }
 #endif
 
+/*! \fn uint qHash(const QGeoCoordinate &coordinate, uint seed = 0)
+    \relates QHash
+    \since Qt 5.7
+
+    Returns a hash value for \a coordinate, using \a seed to seed the calculation.
+*/
+uint qHash(const QGeoCoordinate &coordinate, uint seed)
+{
+    QtPrivate::QHashCombine hash;
+    // north and south pole are geographically equivalent (no matter the longitude)
+    if (coordinate.latitude() != 90.0 && coordinate.latitude() != -90.0)
+        seed = hash(seed, coordinate.longitude());
+    seed = hash(seed, coordinate.latitude());
+    seed = hash(seed, coordinate.altitude());
+    return seed;
+}
+
 QT_END_NAMESPACE
diff --git a/src/positioning/qgeocoordinate.h b/src/positioning/qgeocoordinate.h
index 7b7a4c1f..ddb6274e 100644
--- a/src/positioning/qgeocoordinate.h
+++ b/src/positioning/qgeocoordinate.h
@@ -122,6 +122,8 @@ Q_DECLARE_TYPEINFO(QGeoCoordinate, Q_MOVABLE_TYPE);
 Q_POSITIONING_EXPORT QDebug operator<<(QDebug, const QGeoCoordinate &);
 #endif
 
+Q_POSITIONING_EXPORT uint qHash(const QGeoCoordinate &coordinate, uint seed = 0);
+
 #ifndef QT_NO_DATASTREAM
 Q_POSITIONING_EXPORT QDataStream &operator<<(QDataStream &stream, const QGeoCoordinate &coordinate);
 Q_POSITIONING_EXPORT QDataStream &operator>>(QDataStream &stream, QGeoCoordinate &coordinate);
diff --git a/tests/auto/qgeocoordinate/tst_qgeocoordinate.cpp b/tests/auto/qgeocoordinate/tst_qgeocoordinate.cpp
index 388bf65a..413fa071 100644
--- a/tests/auto/qgeocoordinate/tst_qgeocoordinate.cpp
+++ b/tests/auto/qgeocoordinate/tst_qgeocoordinate.cpp
@@ -900,6 +900,46 @@ private slots:
         QTest::newRow("initialized with altitude") << QGeoCoordinate(1,2,3) << 45
                 << QByteArray("QGeoCoordinate(1, 2, 3) 45");
     }
+
+    void hash()
+    {
+        uint s1 = qHash(QGeoCoordinate(1, 1, 2));
+        uint s2 = qHash(QGeoCoordinate(2, 1, 1));
+        uint s3 = qHash(QGeoCoordinate(1, 2, 1));
+        uint s10 = qHash(QGeoCoordinate(0, 0, 2));
+        uint s20 = qHash(QGeoCoordinate(2, 0, 0));
+        uint s30 = qHash(QGeoCoordinate(0, 2, 0));
+        uint s30NoAlt = qHash(QGeoCoordinate(0, 2));
+        uint s30WithSeed = qHash(QGeoCoordinate(0, 2, 0), 1);
+        uint nullCoordinate = qHash(QGeoCoordinate());
+
+        uint north1 = qHash(QGeoCoordinate(90.0, 34.7, 0));
+        uint north2 = qHash(QGeoCoordinate(90.0, 180, 0));
+
+        uint south1 = qHash(QGeoCoordinate(90.0, 67.7, 34.0));
+        uint south2 = qHash(QGeoCoordinate(90.0, 111, 34.0));
+
+        QVERIFY(s1 != s2);
+        QVERIFY(s2 != s3);
+        QVERIFY(s1 != s3);
+        QVERIFY(s10 != s20);
+        QVERIFY(s20 != s30);
+        QVERIFY(s10 != s30);
+        QVERIFY(s30NoAlt != s30);
+        QVERIFY(s30WithSeed != s30);
+
+        QVERIFY(nullCoordinate != s1);
+        QVERIFY(nullCoordinate != s2);
+        QVERIFY(nullCoordinate != s3);
+        QVERIFY(nullCoordinate != s10);
+        QVERIFY(nullCoordinate != s20);
+        QVERIFY(nullCoordinate != s30);
+        QVERIFY(nullCoordinate != s30NoAlt);
+        QVERIFY(nullCoordinate != s30WithSeed);
+
+        QVERIFY(north1 == north2);
+        QVERIFY(south1 == south2);
+    }
 };
 
 QTEST_GUILESS_MAIN(tst_QGeoCoordinate)