diff options
Diffstat (limited to 'distrib/sdl-1.2.15/src/thread/generic/SDL_syssem.c')
| -rw-r--r-- | distrib/sdl-1.2.15/src/thread/generic/SDL_syssem.c | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/distrib/sdl-1.2.15/src/thread/generic/SDL_syssem.c b/distrib/sdl-1.2.15/src/thread/generic/SDL_syssem.c new file mode 100644 index 0000000..1d289c0 --- /dev/null +++ b/distrib/sdl-1.2.15/src/thread/generic/SDL_syssem.c @@ -0,0 +1,211 @@ +/* + 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" + +/* An implementation of semaphores using mutexes and condition variables */ + +#include "SDL_timer.h" +#include "SDL_thread.h" +#include "SDL_systhread_c.h" + + +#if SDL_THREADS_DISABLED + +SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) +{ + SDL_SetError("SDL not configured with thread support"); + return (SDL_sem *)0; +} + +void SDL_DestroySemaphore(SDL_sem *sem) +{ + return; +} + +int SDL_SemTryWait(SDL_sem *sem) +{ + SDL_SetError("SDL not configured with thread support"); + return -1; +} + +int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout) +{ + SDL_SetError("SDL not configured with thread support"); + return -1; +} + +int SDL_SemWait(SDL_sem *sem) +{ + SDL_SetError("SDL not configured with thread support"); + return -1; +} + +Uint32 SDL_SemValue(SDL_sem *sem) +{ + return 0; +} + +int SDL_SemPost(SDL_sem *sem) +{ + SDL_SetError("SDL not configured with thread support"); + return -1; +} + +#else + +struct SDL_semaphore +{ + Uint32 count; + Uint32 waiters_count; + SDL_mutex *count_lock; + SDL_cond *count_nonzero; +}; + +SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) +{ + SDL_sem *sem; + + sem = (SDL_sem *)SDL_malloc(sizeof(*sem)); + if ( ! sem ) { + SDL_OutOfMemory(); + return NULL; + } + sem->count = initial_value; + sem->waiters_count = 0; + + sem->count_lock = SDL_CreateMutex(); + sem->count_nonzero = SDL_CreateCond(); + if ( ! sem->count_lock || ! sem->count_nonzero ) { + SDL_DestroySemaphore(sem); + return NULL; + } + + return sem; +} + +/* WARNING: + You cannot call this function when another thread is using the semaphore. +*/ +void SDL_DestroySemaphore(SDL_sem *sem) +{ + if ( sem ) { + sem->count = 0xFFFFFFFF; + while ( sem->waiters_count > 0) { + SDL_CondSignal(sem->count_nonzero); + SDL_Delay(10); + } + SDL_DestroyCond(sem->count_nonzero); + if ( sem->count_lock ) { + SDL_mutexP(sem->count_lock); + SDL_mutexV(sem->count_lock); + SDL_DestroyMutex(sem->count_lock); + } + SDL_free(sem); + } +} + +int SDL_SemTryWait(SDL_sem *sem) +{ + int retval; + + if ( ! sem ) { + SDL_SetError("Passed a NULL semaphore"); + return -1; + } + + retval = SDL_MUTEX_TIMEDOUT; + SDL_LockMutex(sem->count_lock); + if ( sem->count > 0 ) { + --sem->count; + retval = 0; + } + SDL_UnlockMutex(sem->count_lock); + + return retval; +} + +int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout) +{ + int retval; + + if ( ! sem ) { + SDL_SetError("Passed a NULL semaphore"); + return -1; + } + + /* A timeout of 0 is an easy case */ + if ( timeout == 0 ) { + return SDL_SemTryWait(sem); + } + + SDL_LockMutex(sem->count_lock); + ++sem->waiters_count; + retval = 0; + while ( (sem->count == 0) && (retval != SDL_MUTEX_TIMEDOUT) ) { + retval = SDL_CondWaitTimeout(sem->count_nonzero, + sem->count_lock, timeout); + } + --sem->waiters_count; + if (retval == 0) { + --sem->count; + } + SDL_UnlockMutex(sem->count_lock); + + return retval; +} + +int SDL_SemWait(SDL_sem *sem) +{ + return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT); +} + +Uint32 SDL_SemValue(SDL_sem *sem) +{ + Uint32 value; + + value = 0; + if ( sem ) { + SDL_LockMutex(sem->count_lock); + value = sem->count; + SDL_UnlockMutex(sem->count_lock); + } + return value; +} + +int SDL_SemPost(SDL_sem *sem) +{ + if ( ! sem ) { + SDL_SetError("Passed a NULL semaphore"); + return -1; + } + + SDL_LockMutex(sem->count_lock); + if ( sem->waiters_count > 0 ) { + SDL_CondSignal(sem->count_nonzero); + } + ++sem->count; + SDL_UnlockMutex(sem->count_lock); + + return 0; +} + +#endif /* SDL_THREADS_DISABLED */ |