blob: 04ac09026ed35068dd01bcdc577d40547b59bae1 (
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
|
// **************************************************************************
// * This file is part of the zenXML project. It is distributed under the *
// * Boost Software License: http://www.boost.org/LICENSE_1_0.txt *
// * Copyright (C) Zenju (zenju AT gmx DOT de) - All Rights Reserved *
// **************************************************************************
#ifndef ZEN_TICK_COUNT_HEADER_3807326
#define ZEN_TICK_COUNT_HEADER_3807326
#include <cstdint>
//#include <algorithm>
#include "type_traits.h"
#include "basic_math.h"
//#include "assert_static.h"
//#include <cmath>
//template <class T> inline
//T dist(T a, T b)
//{
// return a > b ? a - b : b - a;
//}
#ifdef FFS_WIN
#include "win.h" //includes "windows.h"
#elif defined FFS_LINUX
#include <time.h> //Posix ::clock_gettime()
#endif
namespace zen
{
//a portable "GetTickCount()" using "wall time equivalent" - e.g. no jumps due to ntp time corrections
class TickVal;
std::int64_t dist(const TickVal& lhs, const TickVal& rhs); //use absolute difference for paranoid security: even QueryPerformanceCounter "wraps-around" at *some* time
std::int64_t ticksPerSec(); //return 0 on error
TickVal getTicks(); //return invalid value on error: !TickVal::isValid()
//############################ implementation ##############################
class TickVal
{
public:
#ifdef FFS_WIN
typedef LARGE_INTEGER NativeVal;
#elif defined FFS_LINUX
typedef timespec NativeVal;
#endif
TickVal() : val_() {}
explicit TickVal(const NativeVal& val) : val_(val) {}
inline friend
std::int64_t dist(const TickVal& lhs, const TickVal& rhs)
{
#ifdef FFS_WIN
return numeric::dist(lhs.val_.QuadPart, rhs.val_.QuadPart); //std::abs(a - b) can lead to overflow!
#elif defined FFS_LINUX
const auto distSec = numeric::dist(lhs.val_.tv_sec, rhs.val_.tv_sec);
const auto distNsec = numeric::dist(lhs.val_.tv_nsec, rhs.val_.tv_nsec);
if (distSec > (std::numeric_limits<std::int64_t>::max() - distNsec) / 1000000000) //truncate instead of overflow!
return std::numeric_limits<std::int64_t>::max();
return distSec * 1000000000 + distNsec;
#endif
}
inline friend
bool operator<(const TickVal& lhs, const TickVal& rhs) //evaluate directly rather than reuse operator-
{
#ifdef FFS_WIN
return lhs.val_.QuadPart < rhs.val_.QuadPart;
#elif defined FFS_LINUX
if (lhs.val_.tv_sec != rhs.val_.tv_sec)
return lhs.val_.tv_sec < rhs.val_.tv_sec;
return lhs.val_.tv_nsec < rhs.val_.tv_nsec;
#endif
}
bool isValid() const { return dist(*this, TickVal()) != 0; }
private:
NativeVal val_;
};
inline
std::int64_t ticksPerSec() //return 0 on error
{
#ifdef FFS_WIN
LARGE_INTEGER frequency = {};
if (!::QueryPerformanceFrequency(&frequency)) //MSDN promises: "The frequency cannot change while the system is running."
return 0;
static_assert(sizeof(std::int64_t) >= sizeof(frequency.QuadPart), "");
return frequency.QuadPart;
#elif defined FFS_LINUX
return 1000000000; //precision: nanoseconds
#endif
}
inline
TickVal getTicks() //return 0 on error
{
#ifdef FFS_WIN
LARGE_INTEGER now = {};
if (!::QueryPerformanceCounter(&now)) //msdn: SetThreadAffinityMask() may be required if there are bugs in BIOS or HAL"
return TickVal();
#elif defined FFS_LINUX
//gettimeofday() seems fine but is deprecated
timespec now = {};
if (::clock_gettime(CLOCK_MONOTONIC_RAW, &now) != 0) //CLOCK_MONOTONIC measures time reliably across processors!
return TickVal();
#endif
return TickVal(now);
}
}
#endif //ZEN_TICK_COUNT_HEADER_3807326
|
