Tools: Introduce semaphore

fairmq/tools/Semaphore.h

@@ -0,0 +1,44 @@
+/********************************************************************************
+ *    Copyright (C) 2019 GSI Helmholtzzentrum fuer Schwerionenforschung GmbH    *
+ *                                                                              *
+ *              This software is distributed under the terms of the             *
+ *              GNU Lesser General Public Licence (LGPL) version 3,             *
+ *                  copied verbatim in the file "LICENSE"                       *
+ ********************************************************************************/
+
+#ifndef FAIR_MQ_TOOLS_SEMAPHORE_H
+#define FAIR_MQ_TOOLS_SEMAPHORE_H
+
+#include <condition_variable>
+#include <cstdint>
+#include <functional>
+#include <mutex>
+
+namespace fair {
+namespace mq {
+namespace tools {
+
+/**
+ * @struct Semaphore Semaphore.h <fairmq/tools/Semaphore.h>
+ * @brief A simple blocking semaphore.
+ */
+struct Semaphore
+{
+  explicit Semaphore();
+  explicit Semaphore(std::size_t initial_count);
+
+  auto Wait() -> void;
+  auto Signal() -> void;
+  auto GetCount() -> std::size_t;
+
+private:
+  std::size_t fCount;
+  std::mutex fMutex;
+  std::condition_variable fCv;
+};
+
+} /* namespace tools */
+} /* namespace mq */
+} /* namespace fair */
+
+#endif /* FAIR_MQ_TOOLS_SEMAPHORE_H */