QCanBusFrame: Easier TimeStamp creation from microseconds only

The new function fromMicroSeconds() automatically converts overflow
microseconds to seconds.

[ChangeLog][QtSerialBus][QCanBusFrame::TimeStamp]
TimeStamp::fromMicroSeconds() creates time stamps with normalized
microseconds and the overflow added to seconds.

Change-Id: I55aab33c1bcf444c50b09415e038a3c8929caeab
Reviewed-by: Denis Shienkov <denis.shienkov@gmail.com>
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>

4 files changed, 33 insertions, 2 deletions

diff --git a/src/plugins/canbus/vectorcan/vectorcanbackend.cpp b/src/plugins/canbus/vectorcan/vectorcanbackend.cpp
index c178b50..d06f124 100644
--- a/src/plugins/canbus/vectorcan/vectorcanbackend.cpp
+++ b/src/plugins/canbus/vectorcan/vectorcanbackend.cpp
@@ -324,8 +324,7 @@ void VectorCanBackendPrivate::startRead()
 
         QCanBusFrame frame(msg.id, QByteArray(reinterpret_cast<const char *>(msg.data),
                                               int(msg.dlc)));
-        const quint64 usecs = event.timeStamp / 1000;
-        frame.setTimeStamp(QCanBusFrame::TimeStamp(usecs / 1000000, usecs % 1000000));
+        frame.setTimeStamp(QCanBusFrame::TimeStamp::fromMicroSeconds(event.timeStamp / 1000));
         frame.setExtendedFrameFormat(msg.id & XL_CAN_EXT_MSG_ID);
         frame.setFrameType((msg.flags & XL_CAN_MSG_FLAG_REMOTE_FRAME)
                            ? QCanBusFrame::RemoteRequestFrame
diff --git a/src/serialbus/qcanbusframe.cpp b/src/serialbus/qcanbusframe.cpp
index da8a595..d963f51 100644
--- a/src/serialbus/qcanbusframe.cpp
+++ b/src/serialbus/qcanbusframe.cpp
@@ -243,6 +243,19 @@ QT_BEGIN_NAMESPACE
     \fn TimeStamp::TimeStamp(qint64 s, qint64 usec)
 
     Constructs a TimeStamp in seconds, \a s, and microseconds, \a usec.
+
+    \note The TimeStamp is not normalized, i.e. microseconds greater 1000000 are not
+    converted to seconds.
+*/
+
+/*!
+    \fn static TimeStamp TimeStamp::fromMicroSeconds(qint64 usec)
+    \since 5.8
+
+    Constructs a normalized TimeStamp from microseconds \a usec.
+
+    The created TimeStamp is normalized, i.e. microsconds greater 1000000 are converted
+    to seconds.
 */
 
 /*!
diff --git a/src/serialbus/qcanbusframe.h b/src/serialbus/qcanbusframe.h
index 5658f94..131236d 100644
--- a/src/serialbus/qcanbusframe.h
+++ b/src/serialbus/qcanbusframe.h
@@ -52,6 +52,10 @@ public:
     public:
         Q_DECL_CONSTEXPR TimeStamp(qint64 s = 0, qint64 usec = 0) Q_DECL_NOTHROW
             : secs(s), usecs(usec) {}
+
+        Q_DECL_CONSTEXPR static TimeStamp fromMicroSeconds(qint64 usec) Q_DECL_NOTHROW
+        { return TimeStamp(usec / 1000000, usec % 1000000); }
+
         Q_DECL_CONSTEXPR qint64 seconds() const Q_DECL_NOTHROW { return secs; }
         Q_DECL_CONSTEXPR qint64 microSeconds() const Q_DECL_NOTHROW { return usecs; }
 
diff --git a/tests/auto/qcanbusframe/tst_qcanbusframe.cpp b/tests/auto/qcanbusframe/tst_qcanbusframe.cpp
index 763d116..e647a55 100644
--- a/tests/auto/qcanbusframe/tst_qcanbusframe.cpp
+++ b/tests/auto/qcanbusframe/tst_qcanbusframe.cpp
@@ -140,6 +140,21 @@ void tst_QCanBusFrame::timeStamp()
     timeStamp.setSeconds(4);
     QCOMPARE(timeStamp.seconds(), 4);
     QCOMPARE(timeStamp.microSeconds(), 5);
+
+    // fromMicroSeconds: no microsecond overflow
+    timeStamp = QCanBusFrame::TimeStamp::fromMicroSeconds(999999);
+    QCOMPARE(timeStamp.seconds(), 0);
+    QCOMPARE(timeStamp.microSeconds(), 999999);
+
+    // fromMicroSeconds: microsecond overflow
+    timeStamp = QCanBusFrame::TimeStamp::fromMicroSeconds(1000000);
+    QCOMPARE(timeStamp.seconds(), 1);
+    QCOMPARE(timeStamp.microSeconds(), 0);
+
+    // fromMicroSeconds: microsecond overflow
+    timeStamp = QCanBusFrame::TimeStamp::fromMicroSeconds(2000001);
+    QCOMPARE(timeStamp.seconds(), 2);
+    QCOMPARE(timeStamp.microSeconds(), 1);
 }
 
 void tst_QCanBusFrame::tst_isValid_data()