src/timer/SDL_timer.c
author Sam Lantinga <slouken@libsdl.org>
Thu, 06 May 2004 15:55:06 +0000
changeset 886 05c551e5bc64
parent 252 e8157fcb3114
child 1023 e719ee25439d
permissions -rw-r--r--
Date: Sat, 24 Apr 2004 15:13:32 +0300 From: "Mike Gorchak" Subject: SDL updates for the QNX6 1. Updated the README.QNX 2. Updated libtool scripts, which are shipped with SDL for QNX6 support. 3. Added some code to support the new QNX 6.3.0, which is in beta now. 4. Added code to detect the hw features, which driver supports. 5. Added hw alpha blits code. 6. Fixed bug when application switches to fullscreen more the 2 times. (afte\ r that window becames always stay on top). 7. Updated a bit README for the tests. 8. Added information about acceleration show in the testalpha.c test. 9. Added small fixes to the testoverlay2.c test. 10. Added alpha and cc+alpha blits benchmarks to the testvidinfo.c test.

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997, 1998  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
    5635-34 Springhouse Dr.
    Pleasanton, CA 94588 (USA)
    slouken@libsdl.org
*/

#ifdef SAVE_RCSID
static char rcsid =
 "@(#) $Id$";
#endif

#include <stdlib.h>
#include <stdio.h>			/* For the definition of NULL */

#include "SDL_error.h"
#include "SDL_timer.h"
#include "SDL_timer_c.h"
#include "SDL_mutex.h"
#include "SDL_systimer.h"

/* #define DEBUG_TIMERS */

int SDL_timer_started = 0;
int SDL_timer_running = 0;

/* Data to handle a single periodic alarm */
Uint32 SDL_alarm_interval = 0;
SDL_TimerCallback SDL_alarm_callback;

static SDL_bool list_changed = SDL_FALSE;

/* Data used for a thread-based timer */
static int SDL_timer_threaded = 0;

struct _SDL_TimerID {
	Uint32 interval;
	SDL_NewTimerCallback cb;
	void *param;
	Uint32 last_alarm;
	struct _SDL_TimerID *next;
};

static SDL_TimerID SDL_timers = NULL;
static Uint32 num_timers = 0;
static SDL_mutex *SDL_timer_mutex;

/* Set whether or not the timer should use a thread.
   This should not be called while the timer subsystem is running.
*/
int SDL_SetTimerThreaded(int value)
{
	int retval;

	if ( SDL_timer_started ) {
		SDL_SetError("Timer already initialized");
		retval = -1;
	} else {
		retval = 0;
		SDL_timer_threaded = value;
	}
	return retval;
}

int SDL_TimerInit(void)
{
	int retval;

	SDL_timer_running = 0;
	SDL_SetTimer(0, NULL);
	retval = 0;
	if ( ! SDL_timer_threaded ) {
		retval = SDL_SYS_TimerInit();
	}
	if ( SDL_timer_threaded ) {
		SDL_timer_mutex = SDL_CreateMutex();
	}
	SDL_timer_started = 1;
	return(retval);
}

void SDL_TimerQuit(void)
{
	SDL_SetTimer(0, NULL);
	if ( SDL_timer_threaded < 2 ) {
		SDL_SYS_TimerQuit();
	}
	if ( SDL_timer_threaded ) {
		SDL_DestroyMutex(SDL_timer_mutex);
	}
	SDL_timer_started = 0;
	SDL_timer_threaded = 0;
}

void SDL_ThreadedTimerCheck(void)
{
	Uint32 now, ms;
	SDL_TimerID t, prev, next;
	int removed;

	now = SDL_GetTicks();

	SDL_mutexP(SDL_timer_mutex);
	for ( prev = NULL, t = SDL_timers; t; t = next ) {
		removed = 0;
		ms = t->interval - SDL_TIMESLICE;
		next = t->next;
		if ( (t->last_alarm < now) && ((now - t->last_alarm) > ms) ) {
			if ( (now - t->last_alarm) < t->interval ) {
				t->last_alarm += t->interval;
			} else {
				t->last_alarm = now;
			}
			list_changed = SDL_FALSE;
#ifdef DEBUG_TIMERS
			printf("Executing timer %p (thread = %d)\n",
						t, SDL_ThreadID());
#endif
			SDL_mutexV(SDL_timer_mutex);
			ms = t->cb(t->interval, t->param);
			SDL_mutexP(SDL_timer_mutex);
			if ( list_changed ) {
				/* Abort, list of timers has been modified */
				break;
			}
			if ( ms != t->interval ) {
				if ( ms ) {
					t->interval = ROUND_RESOLUTION(ms);
				} else { /* Remove the timer from the linked list */
#ifdef DEBUG_TIMERS
					printf("SDL: Removing timer %p\n", t);
#endif
					if ( prev ) {
						prev->next = next;
					} else {
						SDL_timers = next;
					}
					free(t);
					-- num_timers;
					removed = 1;
				}
			}
		}
		/* Don't update prev if the timer has disappeared */
		if ( ! removed ) {
			prev = t;
		}
	}
	SDL_mutexV(SDL_timer_mutex);
}

SDL_TimerID SDL_AddTimer(Uint32 interval, SDL_NewTimerCallback callback, void *param)
{
	SDL_TimerID t;
	if ( ! SDL_timer_mutex ) {
		if ( SDL_timer_started ) {
			SDL_SetError("This platform doesn't support multiple timers");
		} else {
			SDL_SetError("You must call SDL_Init(SDL_INIT_TIMER) first");
		}
		return NULL;
	}
	if ( ! SDL_timer_threaded ) {
		SDL_SetError("Multiple timers require threaded events!");
		return NULL;
	}
	SDL_mutexP(SDL_timer_mutex);
	t = (SDL_TimerID) malloc(sizeof(struct _SDL_TimerID));
	if ( t ) {
		t->interval = ROUND_RESOLUTION(interval);
		t->cb = callback;
		t->param = param;
		t->last_alarm = SDL_GetTicks();
		t->next = SDL_timers;
		SDL_timers = t;
		++ num_timers;
		list_changed = SDL_TRUE;
		SDL_timer_running = 1;
	}
#ifdef DEBUG_TIMERS
	printf("SDL_AddTimer(%d) = %08x num_timers = %d\n", interval, (Uint32)t, num_timers);
#endif
	SDL_mutexV(SDL_timer_mutex);
	return t;
}

SDL_bool SDL_RemoveTimer(SDL_TimerID id)
{
	SDL_TimerID t, prev = NULL;
	SDL_bool removed;

	removed = SDL_FALSE;
	SDL_mutexP(SDL_timer_mutex);
	/* Look for id in the linked list of timers */
	for (t = SDL_timers; t; prev=t, t = t->next ) {
		if ( t == id ) {
			if(prev) {
				prev->next = t->next;
			} else {
				SDL_timers = t->next;
			}
			free(t);
			-- num_timers;
			removed = SDL_TRUE;
			list_changed = SDL_TRUE;
			break;
		}
	}
#ifdef DEBUG_TIMERS
	printf("SDL_RemoveTimer(%08x) = %d num_timers = %d thread = %d\n", (Uint32)id, removed, num_timers, SDL_ThreadID());
#endif
	SDL_mutexV(SDL_timer_mutex);
	return removed;
}

static void SDL_RemoveAllTimers(SDL_TimerID t)
{
	SDL_TimerID freeme;

	/* Changed to non-recursive implementation.
	   The recursive implementation is elegant, but subject to 
	   stack overflow if there are lots and lots of timers.
	 */
	while ( t ) {
		freeme = t;
		t = t->next;
		free(freeme);
	}
}

/* Old style callback functions are wrapped through this */
static Uint32 callback_wrapper(Uint32 ms, void *param)
{
	SDL_TimerCallback func = (SDL_TimerCallback) param;
	return (*func)(ms);
}

int SDL_SetTimer(Uint32 ms, SDL_TimerCallback callback)
{
	int retval;

#ifdef DEBUG_TIMERS
	printf("SDL_SetTimer(%d)\n", ms);
#endif
	retval = 0;
	if ( SDL_timer_running ) {	/* Stop any currently running timer */
		SDL_timer_running = 0;
		if ( SDL_timer_threaded ) {
			SDL_mutexP(SDL_timer_mutex);
			SDL_RemoveAllTimers(SDL_timers);
			SDL_timers = NULL;
			SDL_mutexV(SDL_timer_mutex);
		} else {
			SDL_SYS_StopTimer();
		}
	}
	if ( ms ) {
		if ( SDL_timer_threaded ) {
			retval = (SDL_AddTimer(ms, callback_wrapper,
					       (void *)callback) != NULL);
		} else {
			SDL_timer_running = 1;
			SDL_alarm_interval = ms;
			SDL_alarm_callback = callback;
			retval = SDL_SYS_StartTimer();
		}
	}
	return retval;
}