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Diffstat (limited to 'src/corelib/tools/qelapsedtimer_generic.cpp')
-rw-r--r-- | src/corelib/tools/qelapsedtimer_generic.cpp | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/src/corelib/tools/qelapsedtimer_generic.cpp b/src/corelib/tools/qelapsedtimer_generic.cpp new file mode 100644 index 0000000000..508c94fb1d --- /dev/null +++ b/src/corelib/tools/qelapsedtimer_generic.cpp @@ -0,0 +1,194 @@ +/**************************************************************************** +** +** 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 |