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halflife-sdk-steam/game_shared/perf_counter.h

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//========= Copyright <20> 1996-2002, Valve LLC, All rights reserved. ============
//
// Purpose:
//
// $NoKeywords: $
//=============================================================================
// Extracted from dbg.c (Michael S. Booth)
#ifndef _PERF_COUNTER_H_
#define _PERF_COUNTER_H_
#ifdef _WIN32
#include <windows.h> // Currently needed for IsBadReadPtr and IsBadWritePtr
#include <io.h>
#include <direct.h>
#else
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#ifdef OSX
#include <limits.h>
#else
#include <linux/limits.h>
#endif
#define MAX_PATH PATH_MAX
#include <sys/time.h>
#endif
#include <assert.h>
//#include <malloc.h>
#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include <stdlib.h>
#include <math.h>
//-----------------------------------------------------------------------------
// Purpose: quick hacky timer class
//-----------------------------------------------------------------------------
class CPerformanceCounter
{
public:
CPerformanceCounter();
void InitializePerformanceCounter();
double GetCurTime();
private:
int m_iLowShift;
double m_flPerfCounterFreq;
double m_flCurrentTime;
double m_flLastCurrentTime;
};
//-----------------------------------------------------------------------------
// Purpose: Constructor
//-----------------------------------------------------------------------------
inline CPerformanceCounter::CPerformanceCounter()
{
InitializePerformanceCounter();
}
//-----------------------------------------------------------------------------
// Purpose:
//-----------------------------------------------------------------------------
inline void CPerformanceCounter::InitializePerformanceCounter()
{
#ifdef _WIN32
LARGE_INTEGER performanceFreq;
QueryPerformanceFrequency(&performanceFreq);
// get 32 out of the 64 time bits such that we have around
// 1 microsecond resolution
unsigned int lowpart, highpart;
lowpart = (unsigned int)performanceFreq.LowPart;
highpart = (unsigned int)performanceFreq.HighPart;
m_iLowShift = 0;
while (highpart || (lowpart > 2000000.0))
{
m_iLowShift++;
lowpart >>= 1;
lowpart |= (highpart & 1) << 31;
highpart >>= 1;
}
m_flPerfCounterFreq = 1.0 / (double)lowpart;
#endif
}
//-----------------------------------------------------------------------------
// Purpose: returns the current time
//-----------------------------------------------------------------------------
inline double CPerformanceCounter::GetCurTime()
{
#ifdef _WIN32
static int sametimecount;
static unsigned int oldtime;
static int first = 1;
LARGE_INTEGER PerformanceCount;
unsigned int temp, t2;
double time;
QueryPerformanceCounter(&PerformanceCount);
if (m_iLowShift == 0)
{
temp = (unsigned int)PerformanceCount.LowPart;
}
else
{
temp = ((unsigned int)PerformanceCount.LowPart >> m_iLowShift) |
((unsigned int)PerformanceCount.HighPart << (32 - m_iLowShift));
}
if (first)
{
oldtime = temp;
first = 0;
}
else
{
// check for turnover or backward time
if ((temp <= oldtime) && ((oldtime - temp) < 0x10000000))
{
oldtime = temp; // so we can't get stuck
}
else
{
t2 = temp - oldtime;
time = (double)t2 * m_flPerfCounterFreq;
oldtime = temp;
m_flCurrentTime += time;
if (m_flCurrentTime == m_flLastCurrentTime)
{
sametimecount++;
if (sametimecount > 100000)
{
m_flCurrentTime += 1.0;
sametimecount = 0;
}
}
else
{
sametimecount = 0;
}
m_flLastCurrentTime = m_flCurrentTime;
}
}
return m_flCurrentTime;
#else
struct timeval tp;
static int secbase = 0;
gettimeofday( &tp, NULL );
if ( !secbase )
{
secbase = tp.tv_sec;
return ( tp.tv_usec / 1000000.0 );
}
return ( ( tp.tv_sec - secbase ) + tp.tv_usec / 1000000.0 );
#endif /* _WIN32 */
}
#endif // _PERF_COUNTER_H_