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+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qelapsedtimer.h"
+#include "qdatetime.h"
+
+QT_BEGIN_NAMESPACE
+
+/*!
+ Returns the clock type that this QElapsedTimer implementation uses.
+
+ \sa isMonotonic()
+*/
+QElapsedTimer::ClockType QElapsedTimer::clockType()
+{
+ return SystemTime;
+}
+
+/*!
+ Returns true if this is a monotonic clock, false otherwise. See the
+ information on the different clock types to understand which ones are
+ monotonic.
+
+ \sa clockType(), QElapsedTimer::ClockType
+*/
+bool QElapsedTimer::isMonotonic()
+{
+ return false;
+}
+
+/*!
+ Starts this timer. Once started, a timer value can be checked with elapsed() or msecsSinceReference().
+
+ Normally, a timer is started just before a lengthy operation, such as:
+ \snippet doc/src/snippets/qelapsedtimer/main.cpp 0
+
+ Also, starting a timer makes it valid again.
+
+ \sa restart(), invalidate(), elapsed()
+*/
+void QElapsedTimer::start()
+{
+ restart();
+}
+
+/*!
+ Restarts the timer and returns the time elapsed since the previous start.
+ This function is equivalent to obtaining the elapsed time with elapsed()
+ and then starting the timer again with restart(), but it does so in one
+ single operation, avoiding the need to obtain the clock value twice.
+
+ The following example illustrates how to use this function to calibrate a
+ parameter to a slow operation (for example, an iteration count) so that
+ this operation takes at least 250 milliseconds:
+
+ \snippet doc/src/snippets/qelapsedtimer/main.cpp 3
+
+ \sa start(), invalidate(), elapsed()
+*/
+qint64 QElapsedTimer::restart()
+{
+ qint64 old = t1;
+ t1 = QDateTime::currentMSecsSinceEpoch();
+ t2 = 0;
+ 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
+ will result in undefined results.
+
+ \sa start(), restart(), hasExpired(), invalidate()
+*/
+qint64 QElapsedTimer::elapsed() const
+{
+ return QDateTime::currentMSecsSinceEpoch() - t1;
+}
+
+/*!
+ Returns the number of milliseconds between last time this QElapsedTimer
+ object was started and its reference clock's start.
+
+ This number is usually arbitrary for all clocks except the
+ QElapsedTimer::SystemTime clock. For that clock type, this number is the
+ number of milliseconds since January 1st, 1970 at 0:00 UTC (that is, it
+ is the Unix time expressed in milliseconds).
+
+ \sa clockType(), elapsed()
+*/
+qint64 QElapsedTimer::msecsSinceReference() const
+{
+ return t1;
+}
+
+/*!
+ Returns the number of milliseconds between this QElapsedTimer and \a
+ other. If \a other was started before this object, the returned value
+ will be positive. If it was started later, the returned value will be
+ negative.
+
+ The return value is undefined if this object or \a other were invalidated.
+
+ \sa secsTo(), elapsed()
+*/
+qint64 QElapsedTimer::msecsTo(const QElapsedTimer &other) const
+{
+ qint64 diff = other.t1 - t1;
+ return diff;
+}
+
+/*!
+ Returns the number of seconds between this QElapsedTimer and \a other. If
+ \a other was started before this object, the returned value will be
+ positive. If it was started later, the returned value will be negative.
+
+ The return value is undefined if this object or \a other were invalidated.
+
+ \sa msecsTo(), elapsed()
+*/
+qint64 QElapsedTimer::secsTo(const QElapsedTimer &other) const
+{
+ return msecsTo(other) / 1000;
+}
+
+/*!
+ \relates QElapsedTimer
+
+ Returns true if \a v1 was started before \a v2, false otherwise.
+
+ The returned value is undefined if one of the two parameters is invalid
+ and the other isn't. However, two invalid timers are equal and thus this
+ function will return false.
+*/
+bool operator<(const QElapsedTimer &v1, const QElapsedTimer &v2)
+{
+ return v1.t1 < v2.t1;
+}
+
+QT_END_NAMESPACE