/*

  Simple DirectMedia Layer

  Copyright (C) 1997-2014 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied

  warranty.  In no event will the authors be held liable for any damages

  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,

  including commercial applications, and to alter it and redistribute it

  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not

     claim that you wrote the original software. If you use this software

     in a product, an acknowledgment in the product documentation would be

     appreciated but is not required.

  2. Altered source versions must be plainly marked as such, and must not be

     misrepresented as being the original software.

  3. This notice may not be removed or altered from any source distribution.

*/

#include "../../SDL_internal.h"

#ifdef SDL_TIMER_WINDOWS

#include "../../core/windows/SDL_windows.h"

#include <mmsystem.h>

#include "SDL_timer.h"

#include "SDL_hints.h"

/* The first (low-resolution) ticks value of the application */

static DWORD start;

static BOOL ticks_started = FALSE; 

#ifndef USE_GETTICKCOUNT

/* Store if a high-resolution performance counter exists on the system */

static BOOL hires_timer_available;

/* The first high-resolution ticks value of the application */

static LARGE_INTEGER hires_start_ticks;

/* The number of ticks per second of the high-resolution performance counter */

static LARGE_INTEGER hires_ticks_per_second;

#ifndef __WINRT__

static void

timeSetPeriod(UINT uPeriod)

{

    static UINT timer_period = 0;

    if (uPeriod != timer_period) {

        if (timer_period) {

            timeEndPeriod(timer_period);

        }

        timer_period = uPeriod;

        if (timer_period) {

            timeBeginPeriod(timer_period);

        }

    }

}

static void

SDL_TimerResolutionChanged(void *userdata, const char *name, const char *oldValue, const char *hint)

{

    UINT uPeriod;

    /* Unless the hint says otherwise, let's have good sleep precision */

    if (hint && *hint) {

        uPeriod = SDL_atoi(hint);

    } else {

        uPeriod = 1;

    }

    if (uPeriod || oldValue != hint) {

        timeSetPeriod(uPeriod);

    }

}

#endif /* ifndef __WINRT__ */

#endif /* !USE_GETTICKCOUNT */

void

SDL_TicksInit(void)

{

    if (ticks_started) {

        return;

    }

    ticks_started = SDL_TRUE;

    /* Set first ticks value */

#ifdef USE_GETTICKCOUNT

    start = GetTickCount();

#else

    /* QueryPerformanceCounter has had problems in the past, but lots of games

       use it, so we'll rely on it here.

     */

    if (QueryPerformanceFrequency(&hires_ticks_per_second) == TRUE) {

        hires_timer_available = TRUE;

        QueryPerformanceCounter(&hires_start_ticks);

    } else {

        hires_timer_available = FALSE;

#ifdef __WINRT__

        start = 0;            /* the timer failed to start! */

#else

        timeSetPeriod(1);     /* use 1 ms timer precision */

        start = timeGetTime();

        SDL_AddHintCallback(SDL_HINT_TIMER_RESOLUTION,

                            SDL_TimerResolutionChanged, NULL);

#endif /* __WINRT__ */

    }

#endif /* USE_GETTICKCOUNT */

}

void

SDL_TicksQuit(void)

{

#ifndef USE_GETTICKCOUNT

    if (!hires_timer_available) {

#ifndef __WINRT__

        SDL_DelHintCallback(SDL_HINT_TIMER_RESOLUTION,

                            SDL_TimerResolutionChanged, NULL);

        timeSetPeriod(0);

#endif /* __WINRT__ */

    }

#endif /* USE_GETTICKCOUNT */

    ticks_started = SDL_FALSE;

}

Uint32

SDL_GetTicks(void)

{

    DWORD now;

#ifndef USE_GETTICKCOUNT

    LARGE_INTEGER hires_now;

#endif

    if (!ticks_started) {

        SDL_TicksInit();

    }

#ifdef USE_GETTICKCOUNT

    now = GetTickCount();

#else

    if (hires_timer_available) {

        QueryPerformanceCounter(&hires_now);

        hires_now.QuadPart -= hires_start_ticks.QuadPart;

        hires_now.QuadPart *= 1000;

        hires_now.QuadPart /= hires_ticks_per_second.QuadPart;

        return (DWORD) hires_now.QuadPart;

    } else {

#ifdef __WINRT__

        now = 0;

#else

        now = timeGetTime();

#endif /* __WINRT__ */

    }

#endif

    return (now - start);

}

Uint64

SDL_GetPerformanceCounter(void)

{

    LARGE_INTEGER counter;

    if (!QueryPerformanceCounter(&counter)) {

        return SDL_GetTicks();

    }

    return counter.QuadPart;

}

Uint64

SDL_GetPerformanceFrequency(void)

{

    LARGE_INTEGER frequency;

    if (!QueryPerformanceFrequency(&frequency)) {

        return 1000;

    }

    return frequency.QuadPart;

}

static void

Sleep(DWORD timeout)

{

    static HANDLE mutex = 0;

    if ( ! mutex )

    {

        mutex = CreateEventEx(0, 0, 0, EVENT_ALL_ACCESS);

    }

    WaitForSingleObjectEx(mutex, timeout, FALSE);

}

#endif

void

SDL_Delay(Uint32 ms)

{

    Sleep(ms);

}

#endif /* SDL_TIMER_WINDOWS */

/* vi: set ts=4 sw=4 expandtab: */