ref: 1f055ccfe86822e48f83b32340c0a41caed01b3b
dir: /external/SDL2/src/thread/pthread/SDL_syssem.c/
/* Simple DirectMedia Layer Copyright (C) 1997-2018 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: */