ParaUtils.hpp

#pragma once
//-----------------------------------------------------------------------------
// Class:   Header only utility functions 
// Authors: LiXizhi
// Emails:  LiXizhi@yeah.net
// Company: ParaEngine Co.
// Date:    2010.4.21
// Desc: Some util functions that can be used in plugins without the need to link with the core library. 
//-----------------------------------------------------------------------------
#include "PEtypes.h"

#ifdef WIN32
#include <time.h>
#else
// linux implementation
#include <sys/time.h>
#include <unistd.h>
#endif 

namespace ParaEngine
{
    class CParaUtils
    {
    public:
        static int64 GetTimeMS()
        {
            return (GetTimeUS()/1000);
        }

        static int64 GetTimeUS()
        {
            static bool initialized=false;
            static int queryCount=0;
#ifdef WIN32
            // win32 implementation
            static DWORD g_ProcMask;
            static DWORD g_SysMask;
            static HANDLE g_Thread;
            static LARGE_INTEGER g_yo;

            // Win32
            if ( initialized == false)
            {
                initialized = true;
                // Save the current process
                HANDLE mProc = GetCurrentProcess();

                // Get the current Affinity
#if _MSC_VER >= 1400 && defined (_M_X64)
                GetProcessAffinityMask(mProc, (PDWORD_PTR)&g_ProcMask, (PDWORD_PTR)&g_SysMask);
#else
                GetProcessAffinityMask(mProc, &g_ProcMask, &g_SysMask);
#endif
                g_Thread = GetCurrentThread();

                QueryPerformanceFrequency( &g_yo );
            }

            int64 curTime;
            static int64 lastQueryVal=(int64)0;
            //  static unsigned long lastTickCountVal = GetTickCount();

            LARGE_INTEGER PerfVal;

            // Set affinity to the first core
            SetThreadAffinityMask(g_Thread, 1);

            // Docs: On a multiprocessor computer, it should not matter which processor is called.
            // However, g_you can get different results on different processors due to bugs in the basic input/output system (BIOS) or the hardware abstraction layer (HAL). To specify processor affinity for a thread, use the SetThreadAffinityMask function.
            // Query the timer
            QueryPerformanceCounter( &PerfVal );

            // Reset affinity
            SetThreadAffinityMask(g_Thread, g_ProcMask);


            int64 quotient, remainder;
            quotient=((PerfVal.QuadPart) / g_yo.QuadPart);
            remainder=((PerfVal.QuadPart) % g_yo.QuadPart);
            curTime = (int64) quotient*(int64)1000000 + (remainder*(int64)1000000 / g_yo.QuadPart);

            // 08/26/08 - With the below workaround, the time seems to jump forward regardless.
            // Just make sure the time doesn't go backwards
            if (curTime < lastQueryVal)
                return lastQueryVal;
            lastQueryVal=curTime;

            return curTime;
#else
            static timeval tp;
            static int64 initialTime;

            // Linux implementation
            if ( initialized == false)
            {
                gettimeofday( &tp, 0 );
                initialized=true;
                // I do this because otherwise RakNetTime in milliseconds won't work as it will underflow when dividing by 1000 to do the conversion
                initialTime = ( tp.tv_sec ) * (int64) 1000000 + ( tp.tv_usec );
            }

            // GCC
            int64 curTime;
            gettimeofday( &tp, 0 );

            curTime = ( tp.tv_sec ) * (int64) 1000000 + ( tp.tv_usec );
            // Subtract from initialTime so the millisecond conversion does not underflow
            return curTime - initialTime;
#endif
        }
    };
}