/*

    SDL - Simple DirectMedia Layer

    Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002  Sam Lantinga

    This library is free software; you can redistribute it and/or

    modify it under the terms of the GNU Library General Public

    License as published by the Free Software Foundation; either

    version 2 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,

    but WITHOUT ANY WARRANTY; without even the implied warranty of

    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public

    License along with this library; if not, write to the Free

    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    Sam Lantinga

    slouken@libsdl.org

*/

#ifdef SAVE_RCSID

static char rcsid =

 "@(#) $Id$";

#endif

#include <windows.h>

#include <mmsystem.h>

#include "SDL_timer.h"

#include "SDL_timer_c.h"

#include "SDL_error.h"

#ifdef _WIN32_WCE

#define USE_GETTICKCOUNT

#define USE_SETTIMER

#endif

#define TIME_WRAP_VALUE	(~(DWORD)0)

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

static DWORD start;

#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;

#endif

void SDL_StartTicks(void)

{

	/* Set first ticks value */

#ifdef USE_GETTICKCOUNT

	start = GetTickCount();

#else

	if (QueryPerformanceFrequency(&hires_ticks_per_second) == TRUE)

	{

		hires_timer_available = TRUE;

		QueryPerformanceCounter(&hires_start_ticks);

	}

	else

	{

		hires_timer_available = FALSE;

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

		start = timeGetTime();

	}

#endif

}

Uint32 SDL_GetTicks(void)

{

	DWORD now, ticks;

#ifndef USE_GETTICKCOUNT

	LARGE_INTEGER hires_now;

#endif

#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

	{

		now = timeGetTime();

	}

#endif

	if ( now < start ) {

		ticks = (TIME_WRAP_VALUE-start) + now;

	} else {

		ticks = (now - start);

	}

	return(ticks);

}

void SDL_Delay(Uint32 ms)

{

	Sleep(ms);

}

#ifdef USE_SETTIMER

static UINT WIN_timer;

int SDL_SYS_TimerInit(void)

{

	return(0);

}

void SDL_SYS_TimerQuit(void)

{

	return;

}

/* Forward declaration because this is called by the timer callback */

int SDL_SYS_StartTimer(void);

static VOID CALLBACK TimerCallbackProc(HWND hwnd, UINT uMsg, UINT idEvent, DWORD dwTime)

{

	Uint32 ms;

	ms = SDL_alarm_callback(SDL_alarm_interval);

	if ( ms != SDL_alarm_interval ) {

		KillTimer(NULL, idEvent);

		if ( ms ) {

			SDL_alarm_interval = ROUND_RESOLUTION(ms);

			SDL_SYS_StartTimer();

		} else {

			SDL_alarm_interval = 0;

		}

	}

}

int SDL_SYS_StartTimer(void)

{

	int retval;

	WIN_timer = SetTimer(NULL, 0, SDL_alarm_interval, TimerCallbackProc);

	if ( WIN_timer ) {

		retval = 0;

	} else {

		retval = -1;

	}

	return retval;

}

void SDL_SYS_StopTimer(void)

{

	if ( WIN_timer ) {

		KillTimer(NULL, WIN_timer);

		WIN_timer = 0;

	}

}

#else /* !USE_SETTIMER */

/* Data to handle a single periodic alarm */

static UINT timerID = 0;

static void CALLBACK HandleAlarm(UINT uID,  UINT uMsg, DWORD dwUser,

						DWORD dw1, DWORD dw2)

{

	SDL_ThreadedTimerCheck();

}

int SDL_SYS_TimerInit(void)

{

	MMRESULT result;

	/* Set timer resolution */

	result = timeBeginPeriod(TIMER_RESOLUTION);

	if ( result != TIMERR_NOERROR ) {

		SDL_SetError("Warning: Can't set %d ms timer resolution",

							TIMER_RESOLUTION);

	}

	/* Allow 10 ms of drift so we don't chew on CPU */

	timerID = timeSetEvent(TIMER_RESOLUTION,1,HandleAlarm,0,TIME_PERIODIC);

	if ( ! timerID ) {

		SDL_SetError("timeSetEvent() failed");

		return(-1);

	}

	return(SDL_SetTimerThreaded(1));

}

void SDL_SYS_TimerQuit(void)

{

	if ( timerID ) {

		timeKillEvent(timerID);

	}

	timeEndPeriod(TIMER_RESOLUTION);

}

int SDL_SYS_StartTimer(void)

{

	SDL_SetError("Internal logic error: Win32 uses threaded timer");

	return(-1);

}

void SDL_SYS_StopTimer(void)

{

	return;

}

#endif /* USE_SETTIMER */