QTimeZone: Convert fractional timezones properly.

[ChangeLog][QtCore][QTimeZone] Fixed a wrong timezone conversion when
the POSIX timezone rule contains a fractional timezone (e.g. VET4:30).

Task-number: QTBUG-47037
Change-Id: I5d9052929bbcde174614ccf07c329264603e6431
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

2 files changed, 31 insertions, 6 deletions

diff --git a/src/corelib/tools/qtimezoneprivate_tz.cpp b/src/corelib/tools/qtimezoneprivate_tz.cpp
index 29f0e17012..35380b882a 100644
--- a/src/corelib/tools/qtimezoneprivate_tz.cpp
+++ b/src/corelib/tools/qtimezoneprivate_tz.cpp
@@ -389,12 +389,19 @@ static int parsePosixOffset(const QByteArray &timeRule)
     // Format "[+|-]hh[:mm[:ss]]"
     QList<QByteArray> parts = timeRule.split(':');
     int count = parts.count();
-    if (count == 3)
-        return (parts.at(0).toInt() * -60 * 60) + (parts.at(1).toInt() * 60) + parts.at(2).toInt();
-    else if (count == 2)
-        return (parts.at(0).toInt() * -60 * 60) + (parts.at(1).toInt() * 60);
-    else if (count == 1)
-        return (parts.at(0).toInt() * -60 * 60);
+    if (count == 3) {
+        int hour = parts.at(0).toInt();
+        int sign = hour >= 0 ? -1 : 1;
+        return sign * ((qAbs(hour) * 60 * 60) + (parts.at(1).toInt() * 60) + parts.at(2).toInt());
+    } else if (count == 2) {
+        int hour = parts.at(0).toInt();
+        int sign = hour >= 0 ? -1 : 1;
+        return sign * ((qAbs(hour) * 60 * 60) + (parts.at(1).toInt() * 60));
+    } else if (count == 1) {
+        int hour = parts.at(0).toInt();
+        int sign = hour >= 0 ? -1 : 1;
+        return sign * (qAbs(hour) * 60 * 60);
+    }
     return 0;
 }
 
diff --git a/tests/auto/corelib/tools/qtimezone/tst_qtimezone.cpp b/tests/auto/corelib/tools/qtimezone/tst_qtimezone.cpp
index 2af37eb86e..b511abf670 100644
--- a/tests/auto/corelib/tools/qtimezone/tst_qtimezone.cpp
+++ b/tests/auto/corelib/tools/qtimezone/tst_qtimezone.cpp
@@ -823,6 +823,24 @@ void tst_QTimeZone::tzTest()
     QCOMPARE(dat.offsetFromUtc, 3600);
     QCOMPARE(dat.standardTimeOffset, 3600);
     QCOMPARE(dat.daylightTimeOffset, 0);
+
+    // Test TZ timezone vs UTC timezone for fractionary negative offset
+    QTzTimeZonePrivate  tztz1("America/Caracas");
+    QUtcTimeZonePrivate tzutc1("UTC-04:30");
+    QVERIFY(tztz1.isValid());
+    QVERIFY(tzutc1.isValid());
+    QTzTimeZonePrivate::Data datatz1 = tztz1.data(std);
+    QTzTimeZonePrivate::Data datautc1 = tzutc1.data(std);
+    QCOMPARE(datatz1.offsetFromUtc, datautc1.offsetFromUtc);
+
+    // Test TZ timezone vs UTC timezone for fractionary positive offset
+    QTzTimeZonePrivate  tztz2("Asia/Calcutta");
+    QUtcTimeZonePrivate tzutc2("UTC+05:30");
+    QVERIFY(tztz2.isValid());
+    QVERIFY(tzutc2.isValid());
+    QTzTimeZonePrivate::Data datatz2 = tztz2.data(std);
+    QTzTimeZonePrivate::Data datautc2 = tzutc2.data(std);
+    QCOMPARE(datatz2.offsetFromUtc, datautc2.offsetFromUtc);
 #endif // Q_OS_UNIX
 }