Mercurial > sdl-ios-xcode
view src/timer/SDL_timer.c @ 3550:6b69c5def097
Minor documentation fix
author | Sam Lantinga <slouken@libsdl.org> |
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date | Sat, 12 Dec 2009 20:30:25 +0000 |
parents | 99210400e8b9 |
children | 0d1b16ee0bca |
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/* SDL - Simple DirectMedia Layer Copyright (C) 1997-2009 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; } /* vi: set ts=4 sw=4 expandtab: */