1 files changed, 164 insertions, 0 deletions
diff --git a/src/corelib/kernel/qelapsedtimer_win.cpp b/src/corelib/kernel/qelapsedtimer_win.cpp
new file mode 100644
index 0000000000..520126d262
--- /dev/null
+++ b/src/corelib/kernel/qelapsedtimer_win.cpp
@@ -0,0 +1,164 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qelapsedtimer.h"
+#include <qt_windows.h>
+
+QT_BEGIN_NAMESPACE
+
+// Result of QueryPerformanceFrequency, 0 indicates that the high resolution timer is unavailable
+static quint64 counterFrequency = 0;
+
+static void resolveCounterFrequency()
+{
+    static bool done = false;
+    if (done)
+        return;
+
+    // Retrieve the number of high-resolution performance counter ticks per second
+    LARGE_INTEGER frequency;
+    if (!QueryPerformanceFrequency(&frequency)) {
+        qFatal("QueryPerformanceFrequency failed, even though Microsoft documentation promises it wouldn't.");
+        counterFrequency = 0;
+    } else {
+        counterFrequency = frequency.QuadPart;
+    }
+
+    done = true;
+}
+
+static inline qint64 ticksToNanoseconds(qint64 ticks)
+{
+    if (counterFrequency > 0) {
+        // QueryPerformanceCounter uses an arbitrary frequency
+        qint64 seconds = ticks / counterFrequency;
+        qint64 nanoSeconds = (ticks - seconds * counterFrequency) * 1000000000 / counterFrequency;
+        return seconds * 1000000000 + nanoSeconds;
+    } else {
+        // GetTickCount(64) return milliseconds
+        return ticks * 1000000;
+    }
+}
+
+static quint64 getTickCount()
+{
+    resolveCounterFrequency();
+
+    // This avoids a division by zero and disables the high performance counter if it's not available
+    if (counterFrequency > 0) {
+        LARGE_INTEGER counter;
+
+        bool ok = QueryPerformanceCounter(&counter);
+        Q_ASSERT_X(ok, "QElapsedTimer::start()",
+                   "QueryPerformanceCounter failed, although QueryPerformanceFrequency succeeded.");
+        Q_UNUSED(ok);
+        return counter.QuadPart;
+    }
+
+    return GetTickCount64();
+}
+
+quint64 qt_msectime()
+{
+    return ticksToNanoseconds(getTickCount()) / 1000000;
+}
+
+QElapsedTimer::ClockType QElapsedTimer::clockType() Q_DECL_NOTHROW
+{
+    resolveCounterFrequency();
+
+    if (counterFrequency > 0)
+        return PerformanceCounter;
+    else
+        return TickCounter;
+}
+
+bool QElapsedTimer::isMonotonic() Q_DECL_NOTHROW
+{
+    return true;
+}
+
+void QElapsedTimer::start() Q_DECL_NOTHROW
+{
+    t1 = getTickCount();
+    t2 = 0;
+}
+
+qint64 QElapsedTimer::restart() Q_DECL_NOTHROW
+{
+    qint64 oldt1 = t1;
+    t1 = getTickCount();
+    t2 = 0;
+    return ticksToNanoseconds(t1 - oldt1) / 1000000;
+}
+
+qint64 QElapsedTimer::nsecsElapsed() const Q_DECL_NOTHROW
+{
+    qint64 elapsed = getTickCount() - t1;
+    return ticksToNanoseconds(elapsed);
+}
+
+qint64 QElapsedTimer::elapsed() const Q_DECL_NOTHROW
+{
+    qint64 elapsed = getTickCount() - t1;
+    return ticksToNanoseconds(elapsed) / 1000000;
+}
+
+qint64 QElapsedTimer::msecsSinceReference() const Q_DECL_NOTHROW
+{
+    return ticksToNanoseconds(t1) / 1000000;
+}
+
+qint64 QElapsedTimer::msecsTo(const QElapsedTimer &other) const Q_DECL_NOTHROW
+{
+    qint64 difference = other.t1 - t1;
+    return ticksToNanoseconds(difference) / 1000000;
+}
+
+qint64 QElapsedTimer::secsTo(const QElapsedTimer &other) const Q_DECL_NOTHROW
+{
+    return msecsTo(other) / 1000;
+}
+
+bool operator<(const QElapsedTimer &v1, const QElapsedTimer &v2) Q_DECL_NOTHROW
+{
+    return (v1.t1 - v2.t1) < 0;
+}
+
+QT_END_NAMESPACE