1 files changed, 79 insertions, 0 deletions
diff --git a/qpid/cpp/src/qpid/sys/Semaphore.h b/qpid/cpp/src/qpid/sys/Semaphore.h
new file mode 100644
index 0000000000..9d70f89aeb
--- /dev/null
+++ b/qpid/cpp/src/qpid/sys/Semaphore.h
@@ -0,0 +1,79 @@
+#ifndef _sys_Semaphore_h
+#define _sys_Semaphore_h
+
+/*
+ *
+ * Copyright (c) 2006 The Apache Software Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include "qpid/sys/Monitor.h"
+
+namespace qpid {
+namespace sys {
+
+class Semaphore
+{
+public:
+    Semaphore(uint c = 1) : count(c) {}
+
+    void lock() { acquire(); }
+    void unlock() { release(); }
+    bool trylock() { return tryAcquire(); }
+
+    bool tryAcquire() 
+    {
+        Monitor::ScopedLock l(monitor);
+        if (count) {
+            count--;
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    void acquire() 
+    {
+        Monitor::ScopedLock l(monitor);
+        while (count == 0) monitor.wait();
+        count--;
+    }
+
+    void release(uint n)
+    {
+        Monitor::ScopedLock l(monitor);
+        if (count==0) monitor.notifyAll();
+        count+=n;
+    }
+
+    void release()
+    {
+        release(1);
+    }
+
+    void forceLock()
+    {
+        Monitor::ScopedLock l(monitor);
+        count = 0;
+    }
+
+private:
+    Monitor monitor;
+    uint count;
+};
+
+}}
+
+#endif  /*!_sys_Semaphore_h*/