diff options
Diffstat (limited to 'Utilities/cmlibuv/src/unix/pthread-barrier.c')
-rw-r--r-- | Utilities/cmlibuv/src/unix/pthread-barrier.c | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/Utilities/cmlibuv/src/unix/pthread-barrier.c b/Utilities/cmlibuv/src/unix/pthread-barrier.c new file mode 100644 index 0000000..f57bf25 --- /dev/null +++ b/Utilities/cmlibuv/src/unix/pthread-barrier.c @@ -0,0 +1,120 @@ +/* +Copyright (c) 2016, Kari Tristan Helgason <kthelgason@gmail.com> + +Permission to use, copy, modify, and/or distribute this software for any +purpose with or without fee is hereby granted, provided that the above +copyright notice and this permission notice appear in all copies. + +THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES +WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF +MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR +ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES +WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN +ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF +OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. +*/ +#include "uv-common.h" +#include "pthread-barrier.h" + +#include <stdlib.h> +#include <assert.h> + +/* TODO: support barrier_attr */ +int pthread_barrier_init(pthread_barrier_t* barrier, + const void* barrier_attr, + unsigned count) { + int rc; + _uv_barrier* b; + + if (barrier == NULL || count == 0) + return EINVAL; + + if (barrier_attr != NULL) + return ENOTSUP; + + b = uv__malloc(sizeof(*b)); + if (b == NULL) + return ENOMEM; + + b->in = 0; + b->out = 0; + b->threshold = count; + + if ((rc = pthread_mutex_init(&b->mutex, NULL)) != 0) + goto error2; + if ((rc = pthread_cond_init(&b->cond, NULL)) != 0) + goto error; + + barrier->b = b; + return 0; + +error: + pthread_mutex_destroy(&b->mutex); +error2: + uv__free(b); + return rc; +} + +int pthread_barrier_wait(pthread_barrier_t* barrier) { + int rc; + _uv_barrier* b; + + if (barrier == NULL || barrier->b == NULL) + return EINVAL; + + b = barrier->b; + /* Lock the mutex*/ + if ((rc = pthread_mutex_lock(&b->mutex)) != 0) + return rc; + + /* Increment the count. If this is the first thread to reach the threshold, + wake up waiters, unlock the mutex, then return + PTHREAD_BARRIER_SERIAL_THREAD. */ + if (++b->in == b->threshold) { + b->in = 0; + b->out = b->threshold - 1; + assert(pthread_cond_signal(&b->cond) == 0); + + pthread_mutex_unlock(&b->mutex); + return PTHREAD_BARRIER_SERIAL_THREAD; + } + /* Otherwise, wait for other threads until in is set to 0, + then return 0 to indicate this is not the first thread. */ + do { + if ((rc = pthread_cond_wait(&b->cond, &b->mutex)) != 0) + break; + } while (b->in != 0); + + /* mark thread exit */ + b->out--; + pthread_cond_signal(&b->cond); + pthread_mutex_unlock(&b->mutex); + return rc; +} + +int pthread_barrier_destroy(pthread_barrier_t* barrier) { + int rc; + _uv_barrier* b; + + if (barrier == NULL || barrier->b == NULL) + return EINVAL; + + b = barrier->b; + + if ((rc = pthread_mutex_lock(&b->mutex)) != 0) + return rc; + + if (b->in > 0 || b->out > 0) + rc = EBUSY; + + pthread_mutex_unlock(&b->mutex); + + if (rc) + return rc; + + pthread_cond_destroy(&b->cond); + pthread_mutex_destroy(&b->mutex); + uv__free(barrier->b); + barrier->b = NULL; + return 0; +} |