| /* |
| SDL - Simple DirectMedia Layer |
| Copyright (C) 1997-2006 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_thread.h" |
| #include "SDL_systhread_c.h" |
| |
| |
| struct SDL_semaphore |
| { |
| struct SignalSemaphore Sem; |
| }; |
| |
| #undef D |
| |
| #define D(x) |
| |
| SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) |
| { |
| SDL_sem *sem; |
| |
| sem = (SDL_sem *)SDL_malloc(sizeof(*sem)); |
| |
| if ( ! sem ) { |
| SDL_OutOfMemory(); |
| return(0); |
| } |
| |
| D(bug("Creating semaphore %lx...\n",sem)); |
| |
| SDL_memset(sem,0,sizeof(*sem)); |
| |
| InitSemaphore(&sem->Sem); |
| |
| return(sem); |
| } |
| |
| void SDL_DestroySemaphore(SDL_sem *sem) |
| { |
| D(bug("Destroying semaphore %lx...\n",sem)); |
| |
| if ( sem ) { |
| // Condizioni per liberare i task in attesa? |
| SDL_free(sem); |
| } |
| } |
| |
| int SDL_SemTryWait(SDL_sem *sem) |
| { |
| if ( ! sem ) { |
| SDL_SetError("Passed a NULL semaphore"); |
| return -1; |
| } |
| |
| D(bug("TryWait semaphore...%lx\n",sem)); |
| |
| ObtainSemaphore(&sem->Sem); |
| // ReleaseSemaphore(&sem->Sem); |
| |
| return 1; |
| } |
| |
| int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout) |
| { |
| int retval; |
| |
| |
| if ( ! sem ) { |
| SDL_SetError("Passed a NULL semaphore"); |
| return -1; |
| } |
| |
| D(bug("WaitTimeout (%ld) semaphore...%lx\n",timeout,sem)); |
| |
| /* A timeout of 0 is an easy case */ |
| if ( timeout == 0 ) { |
| ObtainSemaphore(&sem->Sem); |
| return 1; |
| } |
| if(!(retval=AttemptSemaphore(&sem->Sem))) |
| { |
| SDL_Delay(timeout); |
| retval=AttemptSemaphore(&sem->Sem); |
| } |
| |
| if(retval==TRUE) |
| { |
| // ReleaseSemaphore(&sem->Sem); |
| retval=1; |
| } |
| |
| return retval; |
| } |
| |
| int SDL_SemWait(SDL_sem *sem) |
| { |
| ObtainSemaphore(&sem->Sem); |
| return 0; |
| } |
| |
| Uint32 SDL_SemValue(SDL_sem *sem) |
| { |
| Uint32 value; |
| |
| value = 0; |
| if ( sem ) { |
| #ifdef STORMC4_WOS |
| value = sem->Sem.ssppc_SS.ss_NestCount; |
| #else |
| value = sem->Sem.ss_NestCount; |
| #endif |
| } |
| return value; |
| } |
| |
| int SDL_SemPost(SDL_sem *sem) |
| { |
| if ( ! sem ) { |
| SDL_SetError("Passed a NULL semaphore"); |
| return -1; |
| } |
| D(bug("SemPost semaphore...%lx\n",sem)); |
| |
| ReleaseSemaphore(&sem->Sem); |
| return 0; |
| } |
| |