/* 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 #include "SDL_config.h" /* RISC OS semiphores based on linux code */ #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 #include /* For getpid() */ #include #include struct SDL_semaphore { sem_t *sem; sem_t sem_data; }; /* 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_data, 0, initial_value) < 0 ) { SDL_SetError("sem_init() failed"); SDL_free(sem); sem = NULL; } else { sem->sem = &sem->sem_data; } } 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 ) { SDL_SetError("Passed a NULL semaphore"); return -1; } retval = SDL_MUTEX_TIMEDOUT; if ( sem_trywait(sem->sem) == 0 ) { retval = 0; } return retval; } int SDL_SemWait(SDL_sem *sem) { int retval; if ( ! sem ) { SDL_SetError("Passed a NULL semaphore"); return -1; } while ( ((retval = sem_wait(sem->sem)) == -1) && (errno == EINTR) ) {} if ( retval < 0 ) { SDL_SetError("sem_wait() failed"); } return retval; } int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout) { int retval; if ( ! sem ) { SDL_SetError("Passed a NULL semaphore"); return -1; } /* Try the easy cases first */ if ( timeout == 0 ) { return SDL_SemTryWait(sem); } if ( timeout == SDL_MUTEX_MAXWAIT ) { return SDL_SemWait(sem); } /* Ack! We have to busy wait... */ timeout += SDL_GetTicks(); do { retval = SDL_SemTryWait(sem); if ( retval == 0 ) { break; } SDL_Delay(1); } while ( SDL_GetTicks() < timeout ); 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 ) { SDL_SetError("Passed a NULL semaphore"); return -1; } retval = sem_post(sem->sem); if ( retval < 0 ) { SDL_SetError("sem_post() failed"); } return retval; } #endif /* !SDL_THREADS_DISABLED */