From 2ab3d99967d68c79351fe2a3df22c445447e3010 Mon Sep 17 00:00:00 2001
From: Michał Cichoń <michcic@gmail.com>
Date: Tue, 15 Nov 2011 22:28:48 +0100
Subject: Initial import.

---
 pthreads/src/pthread_barrier_wait.c | 104 ++++++++++++++++++++++++++++++++++++
 1 file changed, 104 insertions(+)
 create mode 100644 pthreads/src/pthread_barrier_wait.c

(limited to 'pthreads/src/pthread_barrier_wait.c')

diff --git a/pthreads/src/pthread_barrier_wait.c b/pthreads/src/pthread_barrier_wait.c
new file mode 100644
index 0000000..e0e97e6
--- /dev/null
+++ b/pthreads/src/pthread_barrier_wait.c
@@ -0,0 +1,104 @@
+/*
+ * pthread_barrier_wait.c
+ *
+ * Description:
+ * This translation unit implements barrier primitives.
+ *
+ * --------------------------------------------------------------------------
+ *
+ *      Pthreads-win32 - POSIX Threads Library for Win32
+ *      Copyright(C) 1998 John E. Bossom
+ *      Copyright(C) 1999,2005 Pthreads-win32 contributors
+ * 
+ *      Contact Email: rpj@callisto.canberra.edu.au
+ * 
+ *      The current list of contributors is contained
+ *      in the file CONTRIBUTORS included with the source
+ *      code distribution. The list can also be seen at the
+ *      following World Wide Web location:
+ *      http://sources.redhat.com/pthreads-win32/contributors.html
+ * 
+ *      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 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 in the file COPYING.LIB;
+ *      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"
+
+
+int
+pthread_barrier_wait (pthread_barrier_t * barrier)
+{
+  int result;
+  pthread_barrier_t b;
+
+  ptw32_mcs_local_node_t node;
+
+  if (barrier == NULL || *barrier == (pthread_barrier_t) PTW32_OBJECT_INVALID)
+    {
+      return EINVAL;
+    }
+
+  ptw32_mcs_lock_acquire(&(*barrier)->lock, &node);
+
+  b = *barrier;
+  if (--b->nCurrentBarrierHeight == 0)
+    {
+      /*
+       * We are the last thread to arrive at the barrier before it releases us.
+       * Move our MCS local node to the global scope barrier handle so that the
+       * last thread out (not necessarily us) can release the lock.
+       */
+      ptw32_mcs_node_transfer(&b->proxynode, &node);
+
+      /*
+       * Any threads that have not quite entered sem_wait below when the
+       * multiple_post has completed will nevertheless continue through
+       * the semaphore (barrier).
+       */
+      result = (b->nInitialBarrierHeight > 1
+                ? sem_post_multiple (&(b->semBarrierBreeched),
+				     b->nInitialBarrierHeight - 1) : 0);
+    }
+  else
+    {
+      ptw32_mcs_lock_release(&node);
+      /*
+       * Use the non-cancelable version of sem_wait().
+       *
+       * It is possible that all nInitialBarrierHeight-1 threads are
+       * at this point when the last thread enters the barrier, resets
+       * nCurrentBarrierHeight = nInitialBarrierHeight and leaves.
+       * If pthread_barrier_destroy is called at that moment then the
+       * barrier will be destroyed along with the semas.
+       */
+      result = ptw32_semwait (&(b->semBarrierBreeched));
+    }
+
+  if ((PTW32_INTERLOCKED_LONG)PTW32_INTERLOCKED_INCREMENT_LONG((PTW32_INTERLOCKED_LONGPTR)&b->nCurrentBarrierHeight)
+		  == (PTW32_INTERLOCKED_LONG)b->nInitialBarrierHeight)
+    {
+      /*
+       * We are the last thread to cross this barrier
+       */
+      ptw32_mcs_lock_release(&b->proxynode);
+      if (0 == result)
+        {
+          result = PTHREAD_BARRIER_SERIAL_THREAD;
+        }
+    }
+
+  return (result);
+}
-- 
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