view src/timer/SDL_timer.c @ 1621:f12379c41042

Fixes bug #195: The proper name of Apple's operating system is "Mac OS X" not "MacOS X", as can bee seen in many places, for example http://www.apple.com/macosx/). This contrasts the naming of the old operating system, which was called "MacOS" and today is often refered to as "MacOS Classic". The attached patches fixes the misuse of the name "MacOS X" in both the SDL12 and sdlweb CVS modules.
author Sam Lantinga <slouken@libsdl.org>
date Thu, 13 Apr 2006 13:08:26 +0000
parents d910939febfa
children 14717b52abc0
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/*
    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 "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;

/* 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 SDL_mutex *SDL_timer_mutex;
static volatile SDL_bool list_changed = SDL_FALSE;

/* 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;

	retval = 0;
	if ( SDL_timer_started ) {
		SDL_TimerQuit();
	}
	if ( ! SDL_timer_threaded ) {
		retval = SDL_SYS_TimerInit();
	}
	if ( SDL_timer_threaded ) {
		SDL_timer_mutex = SDL_CreateMutex();
	}
	if ( retval == 0 ) {
		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;
	SDL_bool removed;

	SDL_mutexP(SDL_timer_mutex);
	list_changed = SDL_FALSE;
	now = SDL_GetTicks();
	for ( prev = NULL, t = SDL_timers; t; t = next ) {
		removed = SDL_FALSE;
		ms = t->interval - SDL_TIMESLICE;
		next = t->next;
		if ( (int)(now - t->last_alarm) > (int)ms ) {
			struct _SDL_TimerID timer;

			if ( (now - t->last_alarm) < t->interval ) {
				t->last_alarm += t->interval;
			} else {
				t->last_alarm = now;
			}
#ifdef DEBUG_TIMERS
			printf("Executing timer %p (thread = %d)\n",
				t, SDL_ThreadID());
#endif
			timer = *t;
			SDL_mutexV(SDL_timer_mutex);
			ms = timer.cb(timer.interval, timer.param);
			SDL_mutexP(SDL_timer_mutex);
			if ( list_changed ) {
				/* Abort, list of timers modified */
				/* FIXME: what if ms was changed? */
				break;
			}
			if ( ms != t->interval ) {
				if ( ms ) {
					t->interval = ROUND_RESOLUTION(ms);
				} else {
					/* Remove timer from the list */
#ifdef DEBUG_TIMERS
					printf("SDL: Removing timer %p\n", t);
#endif
					if ( prev ) {
						prev->next = next;
					} else {
						SDL_timers = next;
					}
					SDL_free(t);
					--SDL_timer_running;
					removed = SDL_TRUE;
				}
			}
		}
		/* Don't update prev if the timer has disappeared */
		if ( ! removed ) {
			prev = t;
		}
	}
	SDL_mutexV(SDL_timer_mutex);
}

static SDL_TimerID SDL_AddTimerInternal(Uint32 interval, SDL_NewTimerCallback callback, void *param)
{
	SDL_TimerID t;
	t = (SDL_TimerID) SDL_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;
		++SDL_timer_running;
		list_changed = SDL_TRUE;
	}
#ifdef DEBUG_TIMERS
	printf("SDL_AddTimer(%d) = %08x num_timers = %d\n", interval, (Uint32)t, SDL_timer_running);
#endif
	return t;
}

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_AddTimerInternal(interval, callback, param);
	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;
			}
			SDL_free(t);
			--SDL_timer_running;
			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, SDL_timer_running, SDL_ThreadID());
#endif
	SDL_mutexV(SDL_timer_mutex);
	return removed;
}

/* Old style callback functions are wrapped through this */
static Uint32 SDLCALL 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_threaded ) {
		SDL_mutexP(SDL_timer_mutex);
	}
	if ( SDL_timer_running ) {	/* Stop any currently running timer */
		if ( SDL_timer_threaded ) {
			while ( SDL_timers ) {
				SDL_TimerID freeme = SDL_timers;
				SDL_timers = SDL_timers->next;
				SDL_free(freeme);
			}
			SDL_timer_running = 0;
			list_changed = SDL_TRUE;
		} else {
			SDL_SYS_StopTimer();
			SDL_timer_running = 0;
		}
	}
	if ( ms ) {
		if ( SDL_timer_threaded ) {
			if ( SDL_AddTimerInternal(ms, callback_wrapper, (void *)callback) == NULL ) {
				retval = -1;
			}
		} else {
			SDL_timer_running = 1;
			SDL_alarm_interval = ms;
			SDL_alarm_callback = callback;
			retval = SDL_SYS_StartTimer();
		}
	}
	if ( SDL_timer_threaded ) {
		SDL_mutexV(SDL_timer_mutex);
	}

	return retval;
}