summaryrefslogtreecommitdiffstats
path: root/Utilities/cmlibuv/src/unix/pthread-barrier.c
diff options
context:
space:
mode:
Diffstat (limited to 'Utilities/cmlibuv/src/unix/pthread-barrier.c')
-rw-r--r--Utilities/cmlibuv/src/unix/pthread-barrier.c120
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;
+}