From ce4f3efd78c110c015c54eab05f201d1caac5f8d Mon Sep 17 00:00:00 2001 From: Guenter Bartsch Date: Sun, 20 Apr 2003 16:42:06 +0000 Subject: importing win32 contrib sources and msvc build environment CVS patchset: 4641 CVS date: 2003/04/20 16:42:06 --- win32/contrib/pthreads/barrier.c | 421 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 421 insertions(+) create mode 100644 win32/contrib/pthreads/barrier.c (limited to 'win32/contrib/pthreads/barrier.c') diff --git a/win32/contrib/pthreads/barrier.c b/win32/contrib/pthreads/barrier.c new file mode 100644 index 000000000..eb4542b51 --- /dev/null +++ b/win32/contrib/pthreads/barrier.c @@ -0,0 +1,421 @@ +/* + * barrier.c + * + * Description: + * This translation unit implements barrier primitives. + * + * Pthreads-win32 - POSIX Threads Library for Win32 + * Copyright (C) 1998 + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Library General Public + * License as published by the Free Software Foundation; either + * version 2 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 + * Library General Public License for more details. + * + * You should have received a copy of the GNU Library General Public + * License along with this library; if not, write to the Free + * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, + * MA 02111-1307, USA + */ + +#include "pthread.h" +#include "implement.h" + + +#ifdef __MINGW32__ +#define _LONG long +#define _LPLONG long* +#else +#define _LONG PVOID +#define _LPLONG PVOID* +#endif + +int +pthread_barrier_init(pthread_barrier_t * barrier, + const pthread_barrierattr_t * attr, + unsigned int count) +{ + pthread_barrier_t b; + + if (barrier == NULL || count == 0) + { + return EINVAL; + } + + if (NULL != (b = (pthread_barrier_t) calloc(1, sizeof(*b)))) + { + b->pshared = (attr != NULL && *attr != NULL + ? (*attr)->pshared + : PTHREAD_PROCESS_PRIVATE); + + b->nCurrentBarrierHeight = b->nInitialBarrierHeight = count; + b->iStep = 0; + + /* + * Two semaphores are used in the same way as two stepping + * stones might be used in crossing a stream. Once all + * threads are safely on one stone, the other stone can + * be moved ahead, and the threads can start moving to it. + * If some threads decide to eat their lunch before moving + * then the other threads have to wait. + */ + if (0 == sem_init(&(b->semBarrierBreeched[0]), b->pshared, 0)) + { + if (0 == sem_init(&(b->semBarrierBreeched[1]), b->pshared, 0)) + { + *barrier = b; + return 0; + } + (void) sem_destroy(&(b->semBarrierBreeched[0])); + } + (void) free(b); + } + + return ENOMEM; +} + +int +pthread_barrier_destroy(pthread_barrier_t *barrier) +{ + int result = 0; + pthread_barrier_t b; + + if (barrier == NULL || *barrier == (pthread_barrier_t) PTW32_OBJECT_INVALID) + { + return EINVAL; + } + + b = *barrier; + *barrier = NULL; + + if (0 == (result = sem_destroy(&(b->semBarrierBreeched[0])))) + { + if (0 == (result = sem_destroy(&(b->semBarrierBreeched[1])))) + { + (void) free(b); + return 0; + } + (void) sem_init(&(b->semBarrierBreeched[0]), + b->pshared, + 0); + } + + *barrier = b; + return(result); +} + + +int +pthread_barrier_wait(pthread_barrier_t *barrier) +{ + int result; + int step; + pthread_barrier_t b; + + if (barrier == NULL || *barrier == (pthread_barrier_t) PTW32_OBJECT_INVALID) + { + return EINVAL; + } + + b = *barrier; + step = b->iStep; + + if (0 == InterlockedDecrement((long *) &(b->nCurrentBarrierHeight))) + { + /* Must be done before posting the semaphore. */ + b->nCurrentBarrierHeight = b->nInitialBarrierHeight; + + /* + * There is no race condition between the semaphore wait and post + * because we are using two alternating semas and all threads have + * entered barrier_wait and checked nCurrentBarrierHeight before this + * barrier's sema can be posted. Any threads that have not quite + * entered sem_wait below when the multiple_post has completed + * will nevertheless continue through the semaphore (barrier) + * and will not be left stranded. + */ + result = (b->nInitialBarrierHeight > 1 + ? sem_post_multiple(&(b->semBarrierBreeched[step]), + b->nInitialBarrierHeight - 1) + : 0); + } + else + { + BOOL switchCancelState; + int oldCancelState; + pthread_t self = pthread_self(); + + /* + * This routine is not a cancelation point, so temporarily + * prevent sem_wait() from being one. + * PTHREAD_CANCEL_ASYNCHRONOUS threads can still be canceled. + */ + switchCancelState = (self->cancelType == PTHREAD_CANCEL_DEFERRED && + 0 == pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, + &oldCancelState)); + + result = sem_wait(&(b->semBarrierBreeched[step])); + + if (switchCancelState) + { + (void) pthread_setcancelstate(oldCancelState, NULL); + } + } + + /* + * The first thread across will be the PTHREAD_BARRIER_SERIAL_THREAD. + * It also sets up the alternate semaphore as the next barrier. + */ + if (0 == result) + { + result = ((_LONG) step == + InterlockedCompareExchange((_LPLONG) &(b->iStep), + (_LONG) (1L - step), + (_LONG) step) + ? PTHREAD_BARRIER_SERIAL_THREAD + : 0); + } + + return(result); +} + + +int +pthread_barrierattr_init (pthread_barrierattr_t * attr) + /* + * ------------------------------------------------------ + * DOCPUBLIC + * Initializes a barrier attributes object with default + * attributes. + * + * PARAMETERS + * attr + * pointer to an instance of pthread_barrierattr_t + * + * + * DESCRIPTION + * Initializes a barrier attributes object with default + * attributes. + * + * NOTES: + * 1) Used to define barrier types + * + * RESULTS + * 0 successfully initialized attr, + * ENOMEM insufficient memory for attr. + * + * ------------------------------------------------------ + */ +{ + pthread_barrierattr_t ba; + int result = 0; + + ba = (pthread_barrierattr_t) calloc (1, sizeof (*ba)); + + if (ba == NULL) + { + result = ENOMEM; + } + + ba->pshared = PTHREAD_PROCESS_PRIVATE; + + *attr = ba; + + return (result); + +} /* pthread_barrierattr_init */ + + +int +pthread_barrierattr_destroy (pthread_barrierattr_t * attr) + /* + * ------------------------------------------------------ + * DOCPUBLIC + * Destroys a barrier attributes object. The object can + * no longer be used. + * + * PARAMETERS + * attr + * pointer to an instance of pthread_barrierattr_t + * + * + * DESCRIPTION + * Destroys a barrier attributes object. The object can + * no longer be used. + * + * NOTES: + * 1) Does not affect barrieres created using 'attr' + * + * RESULTS + * 0 successfully released attr, + * EINVAL 'attr' is invalid. + * + * ------------------------------------------------------ + */ +{ + int result = 0; + + if (attr == NULL || *attr == NULL) + { + result = EINVAL; + } + else + { + pthread_barrierattr_t ba = *attr; + + *attr = NULL; + free (ba); + + result = 0; + } + + return (result); + +} /* pthread_barrierattr_destroy */ + + +int +pthread_barrierattr_getpshared (const pthread_barrierattr_t * attr, + int *pshared) + /* + * ------------------------------------------------------ + * DOCPUBLIC + * Determine whether barriers created with 'attr' can be + * shared between processes. + * + * PARAMETERS + * attr + * pointer to an instance of pthread_barrierattr_t + * + * pshared + * will be set to one of: + * + * PTHREAD_PROCESS_SHARED + * May be shared if in shared memory + * + * PTHREAD_PROCESS_PRIVATE + * Cannot be shared. + * + * + * DESCRIPTION + * Mutexes creatd with 'attr' can be shared between + * processes if pthread_barrier_t variable is allocated + * in memory shared by these processes. + * NOTES: + * 1) pshared barriers MUST be allocated in shared + * memory. + * 2) The following macro is defined if shared barriers + * are supported: + * _POSIX_THREAD_PROCESS_SHARED + * + * RESULTS + * 0 successfully retrieved attribute, + * EINVAL 'attr' is invalid, + * + * ------------------------------------------------------ + */ +{ + int result; + + if ((attr != NULL && *attr != NULL) && + (pshared != NULL)) + { + *pshared = (*attr)->pshared; + result = 0; + } + else + { + *pshared = PTHREAD_PROCESS_PRIVATE; + result = EINVAL; + } + + return (result); + +} /* pthread_barrierattr_getpshared */ + + +int +pthread_barrierattr_setpshared (pthread_barrierattr_t * attr, + int pshared) + /* + * ------------------------------------------------------ + * DOCPUBLIC + * Barriers created with 'attr' can be shared between + * processes if pthread_barrier_t variable is allocated + * in memory shared by these processes. + * + * PARAMETERS + * attr + * pointer to an instance of pthread_barrierattr_t + * + * pshared + * must be one of: + * + * PTHREAD_PROCESS_SHARED + * May be shared if in shared memory + * + * PTHREAD_PROCESS_PRIVATE + * Cannot be shared. + * + * DESCRIPTION + * Mutexes creatd with 'attr' can be shared between + * processes if pthread_barrier_t variable is allocated + * in memory shared by these processes. + * + * NOTES: + * 1) pshared barriers MUST be allocated in shared + * memory. + * + * 2) The following macro is defined if shared barriers + * are supported: + * _POSIX_THREAD_PROCESS_SHARED + * + * RESULTS + * 0 successfully set attribute, + * EINVAL 'attr' or pshared is invalid, + * ENOSYS PTHREAD_PROCESS_SHARED not supported, + * + * ------------------------------------------------------ + */ +{ + int result; + + if ((attr != NULL && *attr != NULL) && + ((pshared == PTHREAD_PROCESS_SHARED) || + (pshared == PTHREAD_PROCESS_PRIVATE))) + { + if (pshared == PTHREAD_PROCESS_SHARED) + { + +#if !defined( _POSIX_THREAD_PROCESS_SHARED ) + + result = ENOSYS; + pshared = PTHREAD_PROCESS_PRIVATE; + +#else + + result = 0; + +#endif /* _POSIX_THREAD_PROCESS_SHARED */ + + } + else + { + result = 0; + } + + (*attr)->pshared = pshared; + } + else + { + result = EINVAL; + } + + return (result); + +} /* pthread_barrierattr_setpshared */ -- cgit v1.2.3