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/****************************************************************************
**
** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** 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 Digia. For licensing terms and
** conditions see http://qt.digia.com/licensing. For further information
** use the contact form at http://qt.digia.com/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 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, Digia gives you certain additional
** rights. These rights are described in the Digia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qelapsedtimer.h"
#include <sys/time.h>
#include <time.h>
#include <unistd.h>
#if defined(QT_NO_CLOCK_MONOTONIC) || defined(QT_BOOTSTRAPPED)
// turn off the monotonic clock
# ifdef _POSIX_MONOTONIC_CLOCK
# undef _POSIX_MONOTONIC_CLOCK
# endif
# define _POSIX_MONOTONIC_CLOCK -1
#endif
QT_BEGIN_NAMESPACE
#if (_POSIX_MONOTONIC_CLOCK-0 != 0)
static const bool monotonicClockChecked = true;
static const bool monotonicClockAvailable = _POSIX_MONOTONIC_CLOCK > 0;
#else
static int monotonicClockChecked = false;
static int monotonicClockAvailable = false;
#endif
#ifdef Q_CC_GNU
# define is_likely(x) __builtin_expect((x), 1)
#else
# define is_likely(x) (x)
#endif
#define load_acquire(x) ((volatile const int&)(x))
#define store_release(x,v) ((volatile int&)(x) = (v))
static void unixCheckClockType()
{
#if (_POSIX_MONOTONIC_CLOCK-0 == 0)
if (is_likely(load_acquire(monotonicClockChecked)))
return;
# if defined(_SC_MONOTONIC_CLOCK)
// detect if the system support monotonic timers
long x = sysconf(_SC_MONOTONIC_CLOCK);
store_release(monotonicClockAvailable, x >= 200112L);
# endif
store_release(monotonicClockChecked, true);
#endif
}
static inline qint64 fractionAdjustment()
{
// disabled, but otherwise indicates bad usage of QElapsedTimer
//Q_ASSERT(monotonicClockChecked);
if (monotonicClockAvailable) {
// the monotonic timer is measured in nanoseconds
// 1 ms = 1000000 ns
return 1000*1000ull;
} else {
// gettimeofday is measured in microseconds
// 1 ms = 1000 us
return 1000;
}
}
bool QElapsedTimer::isMonotonic()
{
unixCheckClockType();
return monotonicClockAvailable;
}
QElapsedTimer::ClockType QElapsedTimer::clockType()
{
unixCheckClockType();
return monotonicClockAvailable ? MonotonicClock : SystemTime;
}
static inline void do_gettime(qint64 *sec, qint64 *frac)
{
#if (_POSIX_MONOTONIC_CLOCK-0 >= 0)
unixCheckClockType();
if (is_likely(monotonicClockAvailable)) {
timespec ts;
clock_gettime(CLOCK_MONOTONIC, &ts);
*sec = ts.tv_sec;
*frac = ts.tv_nsec;
return;
}
#endif
// use gettimeofday
struct timeval tv;
::gettimeofday(&tv, 0);
*sec = tv.tv_sec;
*frac = tv.tv_usec;
}
// used in qcore_unix.cpp and qeventdispatcher_unix.cpp
timeval qt_gettime()
{
qint64 sec, frac;
do_gettime(&sec, &frac);
timeval tv;
tv.tv_sec = sec;
tv.tv_usec = frac;
if (monotonicClockAvailable)
tv.tv_usec /= 1000;
return tv;
}
static qint64 elapsedAndRestart(qint64 sec, qint64 frac,
qint64 *nowsec, qint64 *nowfrac)
{
do_gettime(nowsec, nowfrac);
sec = *nowsec - sec;
frac = *nowfrac - frac;
return sec * Q_INT64_C(1000) + frac / fractionAdjustment();
}
void QElapsedTimer::start()
{
do_gettime(&t1, &t2);
}
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;
return elapsedAndRestart(t1, t2, &sec, &frac);
}
qint64 QElapsedTimer::msecsSinceReference() const
{
return t1 * Q_INT64_C(1000) + t2 / fractionAdjustment();
}
qint64 QElapsedTimer::msecsTo(const QElapsedTimer &other) const
{
qint64 secs = other.t1 - t1;
qint64 fraction = other.t2 - t2;
return secs * Q_INT64_C(1000) + fraction / fractionAdjustment();
}
qint64 QElapsedTimer::secsTo(const QElapsedTimer &other) const
{
return other.t1 - t1;
}
bool operator<(const QElapsedTimer &v1, const QElapsedTimer &v2)
{
return v1.t1 < v2.t1 || (v1.t1 == v2.t1 && v1.t2 < v2.t2);
}
QT_END_NAMESPACE
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