aboutsummaryrefslogtreecommitdiffstats
path: root/distrib/sdl-1.2.15/src/timer/SDL_timer.c
blob: 8d137e1a70ab947e660acf6847fe64ff9bc7a1cf (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2012 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_mutex = NULL;
	}
	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;
}