#include "Timer.h"

Timer::Timer()
{
    baseTime = 0.0;
    PlatformInitialize();
}

double Timer::GetTime()
{
    return PlatformGetTime() - baseTime;
}

void Timer::Reset()
{
    baseTime = PlatformGetTime();
}

//----------------------------------------------------------------------------
// Platform-specific stuff follows:
//----------------------------------------------------------------------------
//----------------------------------------------------------------------------
#ifdef _WIN32 // Win32; use Windows QueryPerformanceFrequency API.
//----------------------------------------------------------------------------

#include <windows.h>
#include <time.h>
#include <math.h>

static bool initialized = false;
static BOOL highResolution = FALSE;
static LARGE_INTEGER hiResFrequency;

void Timer::PlatformInitialize()
{
    if(!initialized)
    {
        highResolution = QueryPerformanceFrequency(&hiResFrequency);
        initialized = true;
    }
}

double Timer::PlatformGetTime()
{
    if(highResolution)
    {
        LARGE_INTEGER time;

        if(QueryPerformanceCounter(&time))
        {
            return (double)time.QuadPart / hiResFrequency.QuadPart;
        }
        else
        {
            return NAN;
        }
    }
    else
    {
        return (double)clock() / CLOCKS_PER_SEC;
    }
}

//----------------------------------------------------------------------------
#else // Not Win32; use gettimeofday.
//----------------------------------------------------------------------------

#include <sys/time.h>

Timer::PlatformInitialize()
{
    // Nothing to initialize for gettimeofday;
}

double Timer::PlatformGetTime()
{
    timeval time;

    gettimeofday(&time, (void*)0);

    return time.tv_sec + (time.tv_usec / 1000000.0);
}

//----------------------------------------------------------------------------
#endif
//----------------------------------------------------------------------------