| 1 | /* |
| 2 | SDL - Simple DirectMedia Layer |
| 3 | Copyright (C) 1997-2009 Sam Lantinga |
| 4 | |
| 5 | This library is free software; you can redistribute it and/or |
| 6 | modify it under the terms of the GNU Lesser General Public |
| 7 | License as published by the Free Software Foundation; either |
| 8 | version 2.1 of the License, or (at your option) any later version. |
| 9 | |
| 10 | This library is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | Lesser General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU Lesser General Public |
| 16 | License along with this library; if not, write to the Free Software |
| 17 | Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| 18 | |
| 19 | Sam Lantinga |
| 20 | slouken@libsdl.org |
| 21 | */ |
| 22 | #include "SDL_config.h" |
| 23 | |
| 24 | #include "SDL_timer.h" |
| 25 | #include "SDL_timer_c.h" |
| 26 | #include "SDL_mutex.h" |
| 27 | #include "SDL_systimer.h" |
| 28 | |
| 29 | /* #define DEBUG_TIMERS */ |
| 30 | |
| 31 | int SDL_timer_started = 0; |
| 32 | int SDL_timer_running = 0; |
| 33 | |
| 34 | /* Data to handle a single periodic alarm */ |
| 35 | Uint32 SDL_alarm_interval = 0; |
| 36 | SDL_TimerCallback SDL_alarm_callback; |
| 37 | |
| 38 | /* Data used for a thread-based timer */ |
| 39 | static int SDL_timer_threaded = 0; |
| 40 | |
| 41 | struct _SDL_TimerID { |
| 42 | Uint32 interval; |
| 43 | SDL_NewTimerCallback cb; |
| 44 | void *param; |
| 45 | Uint32 last_alarm; |
| 46 | struct _SDL_TimerID *next; |
| 47 | }; |
| 48 | |
| 49 | static SDL_TimerID SDL_timers = NULL; |
| 50 | static SDL_mutex *SDL_timer_mutex; |
| 51 | static volatile SDL_bool list_changed = SDL_FALSE; |
| 52 | |
| 53 | /* Set whether or not the timer should use a thread. |
| 54 | This should not be called while the timer subsystem is running. |
| 55 | */ |
| 56 | int SDL_SetTimerThreaded(int value) |
| 57 | { |
| 58 | int retval; |
| 59 | |
| 60 | if ( SDL_timer_started ) { |
| 61 | SDL_SetError("Timer already initialized"); |
| 62 | retval = -1; |
| 63 | } else { |
| 64 | retval = 0; |
| 65 | SDL_timer_threaded = value; |
| 66 | } |
| 67 | return retval; |
| 68 | } |
| 69 | |
| 70 | int SDL_TimerInit(void) |
| 71 | { |
| 72 | int retval; |
| 73 | |
| 74 | retval = 0; |
| 75 | if ( SDL_timer_started ) { |
| 76 | SDL_TimerQuit(); |
| 77 | } |
| 78 | if ( ! SDL_timer_threaded ) { |
| 79 | retval = SDL_SYS_TimerInit(); |
| 80 | } |
| 81 | if ( SDL_timer_threaded ) { |
| 82 | SDL_timer_mutex = SDL_CreateMutex(); |
| 83 | } |
| 84 | if ( retval == 0 ) { |
| 85 | SDL_timer_started = 1; |
| 86 | } |
| 87 | return(retval); |
| 88 | } |
| 89 | |
| 90 | void SDL_TimerQuit(void) |
| 91 | { |
| 92 | SDL_SetTimer(0, NULL); |
| 93 | if ( SDL_timer_threaded < 2 ) { |
| 94 | SDL_SYS_TimerQuit(); |
| 95 | } |
| 96 | if ( SDL_timer_threaded ) { |
| 97 | SDL_DestroyMutex(SDL_timer_mutex); |
| 98 | SDL_timer_mutex = NULL; |
| 99 | } |
| 100 | SDL_timer_started = 0; |
| 101 | SDL_timer_threaded = 0; |
| 102 | } |
| 103 | |
| 104 | void SDL_ThreadedTimerCheck(void) |
| 105 | { |
| 106 | Uint32 now, ms; |
| 107 | SDL_TimerID t, prev, next; |
| 108 | SDL_bool removed; |
| 109 | |
| 110 | SDL_mutexP(SDL_timer_mutex); |
| 111 | list_changed = SDL_FALSE; |
| 112 | now = SDL_GetTicks(); |
| 113 | for ( prev = NULL, t = SDL_timers; t; t = next ) { |
| 114 | removed = SDL_FALSE; |
| 115 | ms = t->interval - SDL_TIMESLICE; |
| 116 | next = t->next; |
| 117 | if ( (int)(now - t->last_alarm) > (int)ms ) { |
| 118 | struct _SDL_TimerID timer; |
| 119 | |
| 120 | if ( (now - t->last_alarm) < t->interval ) { |
| 121 | t->last_alarm += t->interval; |
| 122 | } else { |
| 123 | t->last_alarm = now; |
| 124 | } |
| 125 | #ifdef DEBUG_TIMERS |
| 126 | printf("Executing timer %p (thread = %d)\n", |
| 127 | t, SDL_ThreadID()); |
| 128 | #endif |
| 129 | timer = *t; |
| 130 | SDL_mutexV(SDL_timer_mutex); |
| 131 | ms = timer.cb(timer.interval, timer.param); |
| 132 | SDL_mutexP(SDL_timer_mutex); |
| 133 | if ( list_changed ) { |
| 134 | /* Abort, list of timers modified */ |
| 135 | /* FIXME: what if ms was changed? */ |
| 136 | break; |
| 137 | } |
| 138 | if ( ms != t->interval ) { |
| 139 | if ( ms ) { |
| 140 | t->interval = ROUND_RESOLUTION(ms); |
| 141 | } else { |
| 142 | /* Remove timer from the list */ |
| 143 | #ifdef DEBUG_TIMERS |
| 144 | printf("SDL: Removing timer %p\n", t); |
| 145 | #endif |
| 146 | if ( prev ) { |
| 147 | prev->next = next; |
| 148 | } else { |
| 149 | SDL_timers = next; |
| 150 | } |
| 151 | SDL_free(t); |
| 152 | --SDL_timer_running; |
| 153 | removed = SDL_TRUE; |
| 154 | } |
| 155 | } |
| 156 | } |
| 157 | /* Don't update prev if the timer has disappeared */ |
| 158 | if ( ! removed ) { |
| 159 | prev = t; |
| 160 | } |
| 161 | } |
| 162 | SDL_mutexV(SDL_timer_mutex); |
| 163 | } |
| 164 | |
| 165 | static SDL_TimerID SDL_AddTimerInternal(Uint32 interval, SDL_NewTimerCallback callback, void *param) |
| 166 | { |
| 167 | SDL_TimerID t; |
| 168 | t = (SDL_TimerID) SDL_malloc(sizeof(struct _SDL_TimerID)); |
| 169 | if ( t ) { |
| 170 | t->interval = ROUND_RESOLUTION(interval); |
| 171 | t->cb = callback; |
| 172 | t->param = param; |
| 173 | t->last_alarm = SDL_GetTicks(); |
| 174 | t->next = SDL_timers; |
| 175 | SDL_timers = t; |
| 176 | ++SDL_timer_running; |
| 177 | list_changed = SDL_TRUE; |
| 178 | } |
| 179 | #ifdef DEBUG_TIMERS |
| 180 | printf("SDL_AddTimer(%d) = %08x num_timers = %d\n", interval, (Uint32)t, SDL_timer_running); |
| 181 | #endif |
| 182 | return t; |
| 183 | } |
| 184 | |
| 185 | SDL_TimerID SDL_AddTimer(Uint32 interval, SDL_NewTimerCallback callback, void *param) |
| 186 | { |
| 187 | SDL_TimerID t; |
| 188 | if ( ! SDL_timer_mutex ) { |
| 189 | if ( SDL_timer_started ) { |
| 190 | SDL_SetError("This platform doesn't support multiple timers"); |
| 191 | } else { |
| 192 | SDL_SetError("You must call SDL_Init(SDL_INIT_TIMER) first"); |
| 193 | } |
| 194 | return NULL; |
| 195 | } |
| 196 | if ( ! SDL_timer_threaded ) { |
| 197 | SDL_SetError("Multiple timers require threaded events!"); |
| 198 | return NULL; |
| 199 | } |
| 200 | SDL_mutexP(SDL_timer_mutex); |
| 201 | t = SDL_AddTimerInternal(interval, callback, param); |
| 202 | SDL_mutexV(SDL_timer_mutex); |
| 203 | return t; |
| 204 | } |
| 205 | |
| 206 | SDL_bool SDL_RemoveTimer(SDL_TimerID id) |
| 207 | { |
| 208 | SDL_TimerID t, prev = NULL; |
| 209 | SDL_bool removed; |
| 210 | |
| 211 | removed = SDL_FALSE; |
| 212 | SDL_mutexP(SDL_timer_mutex); |
| 213 | /* Look for id in the linked list of timers */ |
| 214 | for (t = SDL_timers; t; prev=t, t = t->next ) { |
| 215 | if ( t == id ) { |
| 216 | if(prev) { |
| 217 | prev->next = t->next; |
| 218 | } else { |
| 219 | SDL_timers = t->next; |
| 220 | } |
| 221 | SDL_free(t); |
| 222 | --SDL_timer_running; |
| 223 | removed = SDL_TRUE; |
| 224 | list_changed = SDL_TRUE; |
| 225 | break; |
| 226 | } |
| 227 | } |
| 228 | #ifdef DEBUG_TIMERS |
| 229 | printf("SDL_RemoveTimer(%08x) = %d num_timers = %d thread = %d\n", (Uint32)id, removed, SDL_timer_running, SDL_ThreadID()); |
| 230 | #endif |
| 231 | SDL_mutexV(SDL_timer_mutex); |
| 232 | return removed; |
| 233 | } |
| 234 | |
| 235 | /* Old style callback functions are wrapped through this */ |
| 236 | static Uint32 SDLCALL callback_wrapper(Uint32 ms, void *param) |
| 237 | { |
| 238 | SDL_TimerCallback func = (SDL_TimerCallback) param; |
| 239 | return (*func)(ms); |
| 240 | } |
| 241 | |
| 242 | int SDL_SetTimer(Uint32 ms, SDL_TimerCallback callback) |
| 243 | { |
| 244 | int retval; |
| 245 | |
| 246 | #ifdef DEBUG_TIMERS |
| 247 | printf("SDL_SetTimer(%d)\n", ms); |
| 248 | #endif |
| 249 | retval = 0; |
| 250 | |
| 251 | if ( SDL_timer_threaded ) { |
| 252 | SDL_mutexP(SDL_timer_mutex); |
| 253 | } |
| 254 | if ( SDL_timer_running ) { /* Stop any currently running timer */ |
| 255 | if ( SDL_timer_threaded ) { |
| 256 | while ( SDL_timers ) { |
| 257 | SDL_TimerID freeme = SDL_timers; |
| 258 | SDL_timers = SDL_timers->next; |
| 259 | SDL_free(freeme); |
| 260 | } |
| 261 | SDL_timer_running = 0; |
| 262 | list_changed = SDL_TRUE; |
| 263 | } else { |
| 264 | SDL_SYS_StopTimer(); |
| 265 | SDL_timer_running = 0; |
| 266 | } |
| 267 | } |
| 268 | if ( ms ) { |
| 269 | if ( SDL_timer_threaded ) { |
| 270 | if ( SDL_AddTimerInternal(ms, callback_wrapper, (void *)callback) == NULL ) { |
| 271 | retval = -1; |
| 272 | } |
| 273 | } else { |
| 274 | SDL_timer_running = 1; |
| 275 | SDL_alarm_interval = ms; |
| 276 | SDL_alarm_callback = callback; |
| 277 | retval = SDL_SYS_StartTimer(); |
| 278 | } |
| 279 | } |
| 280 | if ( SDL_timer_threaded ) { |
| 281 | SDL_mutexV(SDL_timer_mutex); |
| 282 | } |
| 283 | |
| 284 | return retval; |
| 285 | } |