7 files changed, 64 insertions, 19 deletions
diff --git a/src/corelib/tools/qelapsedtimer.h b/src/corelib/tools/qelapsedtimer.h
index b996f6a..4118389 100644
--- a/src/corelib/tools/qelapsedtimer.h
+++ b/src/corelib/tools/qelapsedtimer.h
@@ -68,6 +68,7 @@ public:
     void invalidate();
     bool isValid() const;
 
+    qint64 nsecsElapsed() const;
     qint64 elapsed() const;
     bool hasExpired(qint64 timeout) const;
 
diff --git a/src/corelib/tools/qelapsedtimer_generic.cpp b/src/corelib/tools/qelapsedtimer_generic.cpp
index 85986e6..740f496 100644
--- a/src/corelib/tools/qelapsedtimer_generic.cpp
+++ b/src/corelib/tools/qelapsedtimer_generic.cpp
@@ -103,6 +103,22 @@ qint64 QElapsedTimer::restart()
     return t1 - old;
 }
 
+/*! \since 4.8
+
+    Returns the number of nanoseconds since this QElapsedTimer was last
+    started. Calling this function in a QElapsedTimer that was invalidated
+    will result in undefined results.
+
+    On platforms that do not provide nanosecond resolution, the value returned
+    will be the best estimate available.
+
+    \sa start(), restart(), hasExpired(), invalidate()
+*/
+qint64 QElapsedTimer::nsecsElapsed() const
+{
+    return elapsed() * 1000000;
+}
+
 /*!
     Returns the number of milliseconds since this QElapsedTimer was last
     started. Calling this function in a QElapsedTimer that was invalidated
diff --git a/src/corelib/tools/qelapsedtimer_mac.cpp b/src/corelib/tools/qelapsedtimer_mac.cpp
index 8fceb49..e51f8b3 100644
--- a/src/corelib/tools/qelapsedtimer_mac.cpp
+++ b/src/corelib/tools/qelapsedtimer_mac.cpp
@@ -97,6 +97,12 @@ qint64 QElapsedTimer::restart()
     return absoluteToMSecs(t1 - old);
 }
 
+qint64 QElapsedTimer::nsecsElapsed() const
+{
+    uint64_t cpu_time = mach_absolute_time();
+    return absoluteToNSecs(cpu_time - t1);
+}
+
 qint64 QElapsedTimer::elapsed() const
 {
     uint64_t cpu_time = mach_absolute_time();
diff --git a/src/corelib/tools/qelapsedtimer_symbian.cpp b/src/corelib/tools/qelapsedtimer_symbian.cpp
index 038b102..7cd5f1e 100644
--- a/src/corelib/tools/qelapsedtimer_symbian.cpp
+++ b/src/corelib/tools/qelapsedtimer_symbian.cpp
@@ -64,11 +64,6 @@ static quint64 getMicrosecondFromTick()
     return nanokernel_tick_period * (val | (quint64(highdword) << 32));
 }
 
-static quint64 getMillisecondFromTick()
-{
-    return getMicrosecondFromTick() / 1000;
-}
-
 timeval qt_gettime()
 {
     timeval tv;
@@ -91,36 +86,41 @@ bool QElapsedTimer::isMonotonic()
 
 void QElapsedTimer::start()
 {
-    t1 = getMillisecondFromTick();
+    t1 = getMicrosecondFromTick();
     t2 = 0;
 }
 
 qint64 QElapsedTimer::restart()
 {
     qint64 oldt1 = t1;
-    t1 = getMillisecondFromTick();
+    t1 = getMicrosecondFromTick();
     t2 = 0;
     return t1 - oldt1;
 }
 
+qint64 QElapsedTimer::nsecsElapsed() const
+{
+    return (getMicrosecondFromTick() - t1) * 1000;
+}
+
 qint64 QElapsedTimer::elapsed() const
 {
-    return getMillisecondFromTick() - t1;
+    return (getMicrosecondFromTick() - t1) / 1000;
 }
 
 qint64 QElapsedTimer::msecsSinceReference() const
 {
-    return t1;
+    return t1 / 1000;
 }
 
 qint64 QElapsedTimer::msecsTo(const QElapsedTimer &other) const
 {
-    return other.t1 - t1;
+    return (other.t1 - t1) / 1000;
 }
 
 qint64 QElapsedTimer::secsTo(const QElapsedTimer &other) const
 {
-    return msecsTo(other) / 1000;
+    return msecsTo(other) / 1000000;
 }
 
 bool operator<(const QElapsedTimer &v1, const QElapsedTimer &v2)
diff --git a/src/corelib/tools/qelapsedtimer_unix.cpp b/src/corelib/tools/qelapsedtimer_unix.cpp
index 633fa00..7407e1b 100644
--- a/src/corelib/tools/qelapsedtimer_unix.cpp
+++ b/src/corelib/tools/qelapsedtimer_unix.cpp
@@ -167,6 +167,17 @@ qint64 QElapsedTimer::restart()
     return elapsedAndRestart(t1, t2, &t1, &t2);
 }
 
+qint64 QElapsedTimer::nsecsElapsed() const
+{
+    qint64 sec, frac;
+    do_gettime(&sec, &frac);
+    sec = sec - t1;
+    frac = frac - t2;
+    if (!monotonicClockAvailable)
+        frac *= 1000;
+    return sec * Q_INT64_C(1000000000) + frac;
+}
+
 qint64 QElapsedTimer::elapsed() const
 {
     qint64 sec, frac;
diff --git a/src/corelib/tools/qelapsedtimer_win.cpp b/src/corelib/tools/qelapsedtimer_win.cpp
index c77acaa..3f4acc1 100644
--- a/src/corelib/tools/qelapsedtimer_win.cpp
+++ b/src/corelib/tools/qelapsedtimer_win.cpp
@@ -79,14 +79,14 @@ static void resolveLibs()
     done = true;
 }
 
-static inline qint64 ticksToMilliseconds(qint64 ticks)
+static inline qint64 ticksToNanoseconds(qint64 ticks)
 {
     if (counterFrequency > 0) {
         // QueryPerformanceCounter uses an arbitrary frequency
-        return ticks * 1000 / counterFrequency;
+        return ticks * 1000000000 / counterFrequency;
     } else {
         // GetTickCount(64) return milliseconds
-        return ticks;
+        return ticks * 1000000;
     }
 }
 
@@ -144,24 +144,30 @@ qint64 QElapsedTimer::restart()
     qint64 oldt1 = t1;
     t1 = getTickCount();
     t2 = 0;
-    return ticksToMilliseconds(t1 - oldt1);
+    return ticksToNanoseconds(t1 - oldt1) / 1000000;
+}
+
+qint64 QElapsedTimer::nsecsElapsed() const
+{
+    qint64 elapsed = getTickCount() - t1;
+    return ticksToNanoseconds(elapsed);
 }
 
 qint64 QElapsedTimer::elapsed() const
 {
     qint64 elapsed = getTickCount() - t1;
-    return ticksToMilliseconds(elapsed);
+    return ticksToNanoseconds(elapsed) / 1000000;
 }
 
 qint64 QElapsedTimer::msecsSinceReference() const
 {
-    return ticksToMilliseconds(t1);
+    return ticksToNanoseconds(t1) / 1000000;
 }
 
 qint64 QElapsedTimer::msecsTo(const QElapsedTimer &other) const
 {
     qint64 difference = other.t1 - t1;
-    return ticksToMilliseconds(difference);
+    return ticksToNanoseconds(difference) / 1000000;
 }
 
 qint64 QElapsedTimer::secsTo(const QElapsedTimer &other) const
diff --git a/tests/auto/qelapsedtimer/tst_qelapsedtimer.cpp b/tests/auto/qelapsedtimer/tst_qelapsedtimer.cpp
index 87df57d..bc61f52 100644
--- a/tests/auto/qelapsedtimer/tst_qelapsedtimer.cpp
+++ b/tests/auto/qelapsedtimer/tst_qelapsedtimer.cpp
@@ -122,11 +122,13 @@ void tst_QElapsedTimer::basics()
 
     quint64 value1 = t1.msecsSinceReference();
     qDebug() << value1 << t1;
+    qint64 nsecs = t1.nsecsElapsed();
     qint64 elapsed = t1.restart();
     QVERIFY(elapsed < minResolution);
+    QVERIFY(nsecs / 1000000 < minResolution);
 
     quint64 value2 = t1.msecsSinceReference();
-    qDebug() << value2 << t1 << elapsed;
+    qDebug() << value2 << t1 << elapsed << nsecs;
     // in theory, elapsed == value2 - value1
 
     // However, since QElapsedTimer keeps internally the full resolution,
@@ -150,7 +152,10 @@ void tst_QElapsedTimer::elapsed()
     // don't check: t1.secsTo(t2)
 //    QVERIFY(t1 - t2 < 0);
 
+    QVERIFY(t1.nsecsElapsed() > 0);
     QVERIFY(t1.elapsed() > 0);
+    // the number of elapsed nanoseconds and milliseconds should match
+    QVERIFY(t1.nsecsElapsed() - t1.elapsed() * 1000000 < 1000000);
     QVERIFY(t1.hasExpired(minResolution));
     QVERIFY(!t1.hasExpired(8*minResolution));
     QVERIFY(!t2.hasExpired(minResolution));