/* 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" /* Semaphore functions using the OS/2 API */ #define INCL_DOS #define INCL_DOSERRORS #define INCL_DOSSEMAPHORES #include #include "SDL_thread.h" #include "SDL_timer.h" struct SDL_semaphore { HMTX id; HEV changed; Uint32 value; }; /* Create a semaphore */ DECLSPEC SDL_sem * SDLCALL SDL_CreateSemaphore(Uint32 initial_value) { SDL_sem *sem; ULONG ulrc; /* Allocate sem memory */ sem = (SDL_sem *)SDL_malloc(sizeof(*sem)); if ( sem ) { /* Create the mutex semaphore */ ulrc = DosCreateMutexSem(NULL,&(sem->id),0,TRUE); if ( ulrc ) { SDL_SetError("Couldn't create semaphore"); SDL_free(sem); sem = NULL; } else { DosCreateEventSem(NULL, &(sem->changed), 0, FALSE); sem->value = initial_value; DosReleaseMutexSem(sem->id); } } else { SDL_OutOfMemory(); } return(sem); } /* Free the semaphore */ DECLSPEC void SDLCALL SDL_DestroySemaphore(SDL_sem *sem) { if ( sem ) { if ( sem->id ) { DosCloseEventSem(sem->changed); DosCloseMutexSem(sem->id); sem->id = 0; } SDL_free(sem); } } DECLSPEC int SDLCALL SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout) { ULONG ulrc; if ( ! sem ) { SDL_SetError("Passed a NULL sem"); return -1; } if ( timeout == SDL_MUTEX_MAXWAIT ) { while (1) { ulrc = DosRequestMutexSem(sem->id, SEM_INDEFINITE_WAIT); if (ulrc) { /* if error waiting mutex */ SDL_SetError("DosRequestMutexSem() failed"); return -1; } else if (sem->value) { sem->value--; DosReleaseMutexSem(sem->id); return 0; } else { ULONG ulPostCount; DosResetEventSem(sem->changed, &ulPostCount); DosReleaseMutexSem(sem->id); /* continue waiting until somebody posts the semaphore */ DosWaitEventSem(sem->changed, SEM_INDEFINITE_WAIT); } } } else if ( timeout == 0 ) { ulrc = DosRequestMutexSem(sem->id, SEM_INDEFINITE_WAIT); if (ulrc==NO_ERROR) { if (sem->value) { sem->value--; DosReleaseMutexSem(sem->id); return 0; } else { DosReleaseMutexSem(sem->id); return SDL_MUTEX_TIMEDOUT; } } else { SDL_SetError("DosRequestMutexSem() failed"); return -1; } } else { ulrc = DosRequestMutexSem(sem->id, SEM_INDEFINITE_WAIT); if (ulrc) { /* if error waiting mutex */ SDL_SetError("DosRequestMutexSem() failed"); return -1; } else if (sem->value) { sem->value--; DosReleaseMutexSem(sem->id); return 0; } else { ULONG ulPostCount; DosResetEventSem(sem->changed, &ulPostCount); DosReleaseMutexSem(sem->id); /* continue waiting until somebody posts the semaphore */ ulrc = DosWaitEventSem(sem->changed, timeout); if (ulrc==NO_ERROR) return 0; else return SDL_MUTEX_TIMEDOUT; } } /* never reached */ return -1; } DECLSPEC int SDLCALL SDL_SemTryWait(SDL_sem *sem) { return SDL_SemWaitTimeout(sem, 0); } DECLSPEC int SDLCALL SDL_SemWait(SDL_sem *sem) { return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT); } /* Returns the current count of the semaphore */ DECLSPEC Uint32 SDLCALL SDL_SemValue(SDL_sem *sem) { if ( ! sem ) { SDL_SetError("Passed a NULL sem"); return 0; } return sem->value; } DECLSPEC int SDLCALL SDL_SemPost(SDL_sem *sem) { if ( ! sem ) { SDL_SetError("Passed a NULL sem"); return -1; } if ( DosRequestMutexSem(sem->id,SEM_INDEFINITE_WAIT) ) { SDL_SetError("DosRequestMutexSem() failed"); return -1; } sem->value++; DosPostEventSem(sem->changed); DosReleaseMutexSem(sem->id); return 0; }