summaryrefslogtreecommitdiffstats
path: root/src/corelib/tools/qelapsedtimer_win.cpp
blob: 8171a27ea336b292f5deb298fa0a1cfa46e13dc0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
/****************************************************************************
**
** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** GNU Lesser General Public License Usage
** 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.
**
** 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.
**
** Other Usage
** Alternatively, this file may be used in accordance with the terms and
** conditions contained in a signed written agreement between you and Nokia.
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qelapsedtimer.h"
#include <qt_windows.h>

typedef ULONGLONG (WINAPI *PtrGetTickCount64)(void);
static PtrGetTickCount64 ptrGetTickCount64 = 0;

QT_BEGIN_NAMESPACE

// Result of QueryPerformanceFrequency, 0 indicates that the high resolution timer is unavailable
static quint64 counterFrequency = 0;

static void resolveLibs()
{
    static bool done = false;
    if (done)
        return;

    // try to get GetTickCount64 from the system
    HMODULE kernel32 = GetModuleHandleW(L"kernel32");
    if (!kernel32)
        return;

#if defined(Q_OS_WINCE)
    // does this function exist on WinCE, or will ever exist?
    ptrGetTickCount64 = (PtrGetTickCount64)GetProcAddress(kernel32, L"GetTickCount64");
#else
    ptrGetTickCount64 = (PtrGetTickCount64)GetProcAddress(kernel32, "GetTickCount64");
#endif

    // Retrieve the number of high-resolution performance counter ticks per second
    LARGE_INTEGER frequency;
    if (!QueryPerformanceFrequency(&frequency)) {
        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()
{
    resolveLibs();

    // This avoids a division by zero and disables the high performance counter if it's not available
    if (counterFrequency > 0) {
        LARGE_INTEGER counter;

        if (QueryPerformanceCounter(&counter)) {
            return counter.QuadPart;
        } else {
            qWarning("QueryPerformanceCounter failed, although QueryPerformanceFrequency succeeded.");
            return 0;
        }
    }

    if (ptrGetTickCount64)
        return ptrGetTickCount64();

    static quint32 highdword = 0;
    static quint32 lastval = 0;
    quint32 val = GetTickCount();
    if (val < lastval)
        ++highdword;
    lastval = val;
    return val | (quint64(highdword) << 32);
}

QElapsedTimer::ClockType QElapsedTimer::clockType()
{
    resolveLibs();

    if (counterFrequency > 0)
        return PerformanceCounter;
    else
        return TickCounter;
}

bool QElapsedTimer::isMonotonic()
{
    return true;
}

void QElapsedTimer::start()
{
    t1 = getTickCount();
    t2 = 0;
}

qint64 QElapsedTimer::restart()
{
    qint64 oldt1 = t1;
    t1 = getTickCount();
    t2 = 0;
    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 ticksToNanoseconds(elapsed) / 1000000;
}

qint64 QElapsedTimer::msecsSinceReference() const
{
    return ticksToNanoseconds(t1) / 1000000;
}

qint64 QElapsedTimer::msecsTo(const QElapsedTimer &other) const
{
    qint64 difference = other.t1 - t1;
    return ticksToNanoseconds(difference) / 1000000;
}

qint64 QElapsedTimer::secsTo(const QElapsedTimer &other) const
{
    return msecsTo(other) / 1000;
}

bool operator<(const QElapsedTimer &v1, const QElapsedTimer &v2)
{
    return (v1.t1 - v2.t1) < 0;
}

QT_END_NAMESPACE