src: added ReaderWriterLock, helpers and Semaphore

src/lib/utility/synchronization/ReaderWriterLock.cpp

@@ -0,0 +1,54 @@
+#include "utility/synchronization/ReaderWriterLock.h"
+
+ReaderWriterLock::ReaderWriterLock()
+	: m_readerCount(0)
+	, m_allowedWriters(1)
+	, m_allowedReaders(1)
+{
+}
+
+ReaderWriterLock::ReaderWriterLock(const ReaderWriterLock &lock)
+	: m_readerCount(0)
+	, m_allowedWriters(1)
+	, m_allowedReaders(1)
+{
+}
+
+ReaderWriterLock::~ReaderWriterLock()
+{
+}
+
+void ReaderWriterLock::readerLock()
+{
+	m_allowedReaders.wait();
+	m_allowedReaders.post();
+
+	std::lock_guard<std::mutex> lock(m_readerCountMutex);
+	m_readerCount++;
+	if (m_readerCount == 1)
+	{
+		m_allowedWriters.wait();
+	}
+}
+
+void ReaderWriterLock::readerUnlock()
+{
+	std::lock_guard<std::mutex> lock(m_readerCountMutex);
+	m_readerCount--;
+	if (m_readerCount == 0)
+	{
+		m_allowedWriters.post();
+	}
+}
+
+void ReaderWriterLock::writerLock()
+{
+	m_allowedReaders.wait();
+	m_allowedWriters.wait();
+}
+
+void ReaderWriterLock::writerUnlock()
+{
+	m_allowedWriters.post();
+	m_allowedReaders.post();
+}