/*

    SDL - Simple DirectMedia Layer

    Copyright (C) 1997-2006 Sam Lantinga

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

    modify it under the terms of the GNU Lesser General Public

    License as published by the Free Software Foundation; either

    version 2.1 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

    Lesser General Public License for more details.

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

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

    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga

    slouken@libsdl.org

*/

#include "SDL_config.h"

#include <stdio.h>

#include <sys/time.h>

#include <signal.h>

#include <unistd.h>

#include <string.h>

#include <errno.h>

#include "SDL_timer.h"

#include "../SDL_timer_c.h"

/* The clock_gettime provides monotonous time, so we should use it if

   it's available. The clock_gettime function is behind ifdef

   for __USE_POSIX199309

   Tommi Kyntola (tommi.kyntola@ray.fi) 27/09/2005

*/

#include <time.h>

#endif

#if SDL_THREAD_PTH

#include <pth.h>

#endif

#if SDL_THREADS_DISABLED

#define USE_ITIMER

#endif

/* The first ticks value of the application */

#ifdef HAVE_CLOCK_GETTIME

static struct timespec start;

#else

static struct timeval start;

#endif /* HAVE_CLOCK_GETTIME */

void SDL_StartTicks(void)

{

	/* Set first ticks value */

#if HAVE_CLOCK_GETTIME

	clock_gettime(CLOCK_MONOTONIC,&start);

#else

	gettimeofday(&start, NULL);

#endif

}

Uint32 SDL_GetTicks (void)

{

#if HAVE_CLOCK_GETTIME

	Uint32 ticks;

	struct timespec now;

	clock_gettime(CLOCK_MONOTONIC,&now);

	ticks=(now.tv_sec-start.tv_sec)*1000+(now.tv_nsec-start.tv_nsec)/1000000;

	return(ticks);

#else

	Uint32 ticks;

	struct timeval now;

	gettimeofday(&now, NULL);

	ticks=(now.tv_sec-start.tv_sec)*1000+(now.tv_usec-start.tv_usec)/1000;

	return(ticks);

#endif

}

void SDL_Delay (Uint32 ms)

{

#if SDL_THREAD_PTH

	pth_time_t tv;

	tv.tv_sec  =  ms/1000;

	tv.tv_usec = (ms%1000)*1000;

	pth_nap(tv);

#else

	int was_error;

#if HAVE_NANOSLEEP

	struct timespec elapsed, tv;

#else

	struct timeval tv;

	Uint32 then, now, elapsed;

#endif

	/* Set the timeout interval */

#if HAVE_NANOSLEEP

	elapsed.tv_sec = ms/1000;

	elapsed.tv_nsec = (ms%1000)*1000000;

#else

	then = SDL_GetTicks();

#endif

	do {

		errno = 0;

#if HAVE_NANOSLEEP

		tv.tv_sec = elapsed.tv_sec;

		tv.tv_nsec = elapsed.tv_nsec;

		was_error = nanosleep(&tv, &elapsed);

#else

		/* Calculate the time interval left (in case of interrupt) */

		now = SDL_GetTicks();

		elapsed = (now-then);

		then = now;

		if ( elapsed >= ms ) {

			break;

		}

		ms -= elapsed;

		tv.tv_sec = ms/1000;

		tv.tv_usec = (ms%1000)*1000;

		was_error = select(0, NULL, NULL, NULL, &tv);

#endif /* HAVE_NANOSLEEP */

	} while ( was_error && (errno == EINTR) );

#endif /* SDL_THREAD_PTH */

}

#ifdef USE_ITIMER

static void HandleAlarm(int sig)

{

	Uint32 ms;

	if ( SDL_alarm_callback ) {

		ms = (*SDL_alarm_callback)(SDL_alarm_interval);

		if ( ms != SDL_alarm_interval ) {

			SDL_SetTimer(ms, SDL_alarm_callback);

		}

	}

}

int SDL_SYS_TimerInit(void)

{

	struct sigaction action;

	/* Set the alarm handler (Linux specific) */

	SDL_memset(&action, 0, sizeof(action));

	action.sa_handler = HandleAlarm;

	action.sa_flags = SA_RESTART;

	sigemptyset(&action.sa_mask);

	sigaction(SIGALRM, &action, NULL);

	return(0);

}

void SDL_SYS_TimerQuit(void)

{

	SDL_SetTimer(0, NULL);

}

int SDL_SYS_StartTimer(void)

{

	struct itimerval timer;

	timer.it_value.tv_sec = (SDL_alarm_interval/1000);

	timer.it_value.tv_usec = (SDL_alarm_interval%1000)*1000;

	timer.it_interval.tv_sec = (SDL_alarm_interval/1000);

	timer.it_interval.tv_usec = (SDL_alarm_interval%1000)*1000;

	setitimer(ITIMER_REAL, &timer, NULL);

	return(0);

}

void SDL_SYS_StopTimer(void)

{

	struct itimerval timer;

	SDL_memset(&timer, 0, (sizeof timer));

	setitimer(ITIMER_REAL, &timer, NULL);

}

#else /* USE_ITIMER */

#include "SDL_thread.h"

/* Data to handle a single periodic alarm */

static int timer_alive = 0;

static SDL_Thread *timer = NULL;

static int RunTimer(void *unused)

{

	while ( timer_alive ) {

		if ( SDL_timer_running ) {

			SDL_ThreadedTimerCheck();

		}

		SDL_Delay(1);

	}

	return(0);

}

/* This is only called if the event thread is not running */

int SDL_SYS_TimerInit(void)

{

	timer_alive = 1;

	timer = SDL_CreateThread(RunTimer, NULL);

	if ( timer == NULL )

		return(-1);

	return(SDL_SetTimerThreaded(1));

}

void SDL_SYS_TimerQuit(void)

{

	timer_alive = 0;

	if ( timer ) {

		SDL_WaitThread(timer, NULL);

		timer = NULL;

	}

}

int SDL_SYS_StartTimer(void)

{

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

	return(-1);

}

void SDL_SYS_StopTimer(void)

{

	return;

}

#endif /* USE_ITIMER */