| /* |
| Simple DirectMedia Layer |
| Copyright (C) 1997-2021 Sam Lantinga <slouken@libsdl.org> |
| |
| This software is provided 'as-is', without any express or implied |
| warranty. In no event will the authors be held liable for any damages |
| arising from the use of this software. |
| |
| Permission is granted to anyone to use this software for any purpose, |
| including commercial applications, and to alter it and redistribute it |
| freely, subject to the following restrictions: |
| |
| 1. The origin of this software must not be misrepresented; you must not |
| claim that you wrote the original software. If you use this software |
| in a product, an acknowledgment in the product documentation would be |
| appreciated but is not required. |
| 2. Altered source versions must be plainly marked as such, and must not be |
| misrepresented as being the original software. |
| 3. This notice may not be removed or altered from any source distribution. |
| */ |
| #include "../../SDL_internal.h" |
| |
| #include <errno.h> |
| #include <pthread.h> |
| #include <semaphore.h> |
| #include <sys/time.h> |
| #include <time.h> |
| |
| #include "SDL_thread.h" |
| #include "SDL_timer.h" |
| |
| /* Wrapper around POSIX 1003.1b semaphores */ |
| |
| #if defined(__MACOSX__) || defined(__IPHONEOS__) |
| /* Mac OS X doesn't support sem_getvalue() as of version 10.4 */ |
| #include "../generic/SDL_syssem.c" |
| #else |
| |
| struct SDL_semaphore |
| { |
| sem_t sem; |
| }; |
| |
| /* Create a semaphore, initialized with value */ |
| SDL_sem * |
| SDL_CreateSemaphore(Uint32 initial_value) |
| { |
| SDL_sem *sem = (SDL_sem *) SDL_malloc(sizeof(SDL_sem)); |
| if (sem) { |
| if (sem_init(&sem->sem, 0, initial_value) < 0) { |
| SDL_SetError("sem_init() failed"); |
| SDL_free(sem); |
| sem = NULL; |
| } |
| } else { |
| SDL_OutOfMemory(); |
| } |
| return sem; |
| } |
| |
| void |
| SDL_DestroySemaphore(SDL_sem * sem) |
| { |
| if (sem) { |
| sem_destroy(&sem->sem); |
| SDL_free(sem); |
| } |
| } |
| |
| int |
| SDL_SemTryWait(SDL_sem * sem) |
| { |
| int retval; |
| |
| if (!sem) { |
| return SDL_SetError("Passed a NULL semaphore"); |
| } |
| retval = SDL_MUTEX_TIMEDOUT; |
| if (sem_trywait(&sem->sem) == 0) { |
| retval = 0; |
| } |
| return retval; |
| } |
| |
| int |
| SDL_SemWait(SDL_sem * sem) |
| { |
| int retval; |
| |
| if (!sem) { |
| return SDL_SetError("Passed a NULL semaphore"); |
| } |
| |
| do { |
| retval = sem_wait(&sem->sem); |
| } while (retval < 0 && errno == EINTR); |
| |
| if (retval < 0) { |
| retval = SDL_SetError("sem_wait() failed"); |
| } |
| return retval; |
| } |
| |
| int |
| SDL_SemWaitTimeout(SDL_sem * sem, Uint32 timeout) |
| { |
| int retval; |
| #ifdef HAVE_SEM_TIMEDWAIT |
| #ifndef HAVE_CLOCK_GETTIME |
| struct timeval now; |
| #endif |
| struct timespec ts_timeout; |
| #else |
| Uint32 end; |
| #endif |
| |
| if (!sem) { |
| return SDL_SetError("Passed a NULL semaphore"); |
| } |
| |
| /* Try the easy cases first */ |
| if (timeout == 0) { |
| return SDL_SemTryWait(sem); |
| } |
| if (timeout == SDL_MUTEX_MAXWAIT) { |
| return SDL_SemWait(sem); |
| } |
| |
| #ifdef HAVE_SEM_TIMEDWAIT |
| /* Setup the timeout. sem_timedwait doesn't wait for |
| * a lapse of time, but until we reach a certain time. |
| * This time is now plus the timeout. |
| */ |
| #ifdef HAVE_CLOCK_GETTIME |
| clock_gettime(CLOCK_REALTIME, &ts_timeout); |
| |
| /* Add our timeout to current time */ |
| ts_timeout.tv_nsec += (timeout % 1000) * 1000000; |
| ts_timeout.tv_sec += timeout / 1000; |
| #else |
| gettimeofday(&now, NULL); |
| |
| /* Add our timeout to current time */ |
| ts_timeout.tv_sec = now.tv_sec + (timeout / 1000); |
| ts_timeout.tv_nsec = (now.tv_usec + (timeout % 1000) * 1000) * 1000; |
| #endif |
| |
| /* Wrap the second if needed */ |
| if (ts_timeout.tv_nsec > 1000000000) { |
| ts_timeout.tv_sec += 1; |
| ts_timeout.tv_nsec -= 1000000000; |
| } |
| |
| /* Wait. */ |
| do { |
| retval = sem_timedwait(&sem->sem, &ts_timeout); |
| } while (retval < 0 && errno == EINTR); |
| |
| if (retval < 0) { |
| if (errno == ETIMEDOUT) { |
| retval = SDL_MUTEX_TIMEDOUT; |
| } else { |
| SDL_SetError("sem_timedwait returned an error: %s", strerror(errno)); |
| } |
| } |
| #else |
| end = SDL_GetTicks() + timeout; |
| while ((retval = SDL_SemTryWait(sem)) == SDL_MUTEX_TIMEDOUT) { |
| if (SDL_TICKS_PASSED(SDL_GetTicks(), end)) { |
| break; |
| } |
| SDL_Delay(1); |
| } |
| #endif /* HAVE_SEM_TIMEDWAIT */ |
| |
| return retval; |
| } |
| |
| Uint32 |
| SDL_SemValue(SDL_sem * sem) |
| { |
| int ret = 0; |
| if (sem) { |
| sem_getvalue(&sem->sem, &ret); |
| if (ret < 0) { |
| ret = 0; |
| } |
| } |
| return (Uint32) ret; |
| } |
| |
| int |
| SDL_SemPost(SDL_sem * sem) |
| { |
| int retval; |
| |
| if (!sem) { |
| return SDL_SetError("Passed a NULL semaphore"); |
| } |
| |
| retval = sem_post(&sem->sem); |
| if (retval < 0) { |
| SDL_SetError("sem_post() failed"); |
| } |
| return retval; |
| } |
| |
| #endif /* __MACOSX__ */ |
| /* vi: set ts=4 sw=4 expandtab: */ |