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// **************************************************************************
// * 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 "type_traits.h"
#include "basic_math.h"
#ifdef FFS_WIN
#include "win.h" //includes "windows.h"
#elif defined FFS_LINUX
#include <time.h> //Posix ::clock_gettime()
#elif defined FFS_MAC
#include <mach/mach_time.h>
#endif
//#include <algorithm>
//#include "assert_static.h"
//#include <cmath>
//template <class T> inline
//T dist(T a, T b)
//{
// return a > b ? a - b : b - a;
//}
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;
#elif defined FFS_MAC
typedef uint64_t 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;
#elif defined FFS_MAC
return numeric::dist(lhs.val_, rhs.val_);
#endif
}
inline friend
bool operator<(const TickVal& lhs, const TickVal& rhs)
{
#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;
#elif defined FFS_MAC
return lhs.val_ < rhs.val_;
#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
#elif defined FFS_MAC
mach_timebase_info_data_t tbi = {};
if (::mach_timebase_info(&tbi) != KERN_SUCCESS)
return 0;
return 1000000000 * tbi.denom / tbi.numer;
#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();
#elif defined FFS_MAC
uint64_t now = ::mach_absolute_time(); //can this call fail???
#endif
return TickVal(now);
}
}
#endif //ZEN_TICK_COUNT_HEADER_3807326
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