Add emper::Semaphore

emper/CMakeLists.txt

@@ -11,6 +11,7 @@ add_files(EMPER_SOURCE Debug.cpp)
 add_files(EMPER_SOURCE ContextManager.cpp)
 add_files(EMPER_SOURCE BinaryPrivateSemaphore.cpp)
 add_files(EMPER_SOURCE CountingPrivateSemaphore.cpp)
+add_files(EMPER_SOURCE Semaphore.cpp)
 
 add_files(EMPER_INCLUDE ".")
 add_files(EMPER_INCLUDE "include")

emper/Semaphore.cpp

+#include "Semaphore.hpp"
+
+using namespace emper;
+
+void Semaphore::print() {
+	unsigned int count = this->count;
+	unsigned int waiterListSize;
+	{
+		const std::lock_guard<std::mutex> lock(mutex);
+		waiterListSize = waiterList.size();
+	}
+
+	std::cout << "Semaphore"
+			  << " count=" << count
+			  << " waiterListSize=" << waiterListSize
+			  << std::endl;
+}

emper/Semaphore.hpp

+#pragma once
+
+#include <queue>
+#include <mutex>
+
+#include "BinaryPrivateSemaphore.hpp"
+
+namespace emper {
+
+class Semaphore {
+private:
+
+	std::queue<BinaryPrivateSemaphore*> waiterList;
+	unsigned int count;
+	std::mutex mutex;
+
+public:
+	bool acquire() {
+		bool blocked;
+		mutex.lock();
+		if (count > 0) {
+			count--;
+			mutex.unlock();
+			blocked = false;
+		} else {
+			BinaryPrivateSemaphore semaphore;
+			waiterList.push(&semaphore);
+			mutex.unlock();
+			semaphore.wait();
+			blocked = true;
+		}
+		return blocked;
+	}
+
+	bool release() {
+		mutex.lock();
+		bool waiterListEmpty = waiterList.empty();
+		if (waiterListEmpty) {
+			count++;
+			mutex.unlock();
+		} else {
+			BinaryPrivateSemaphore* semaphore = waiterList.front();
+			waiterList.pop();
+			mutex.unlock();
+			semaphore->signal();
+		}
+		return waiterListEmpty;
+	}
+
+	void print();
+};
+
+}