Initial source commit

minorGems/system/BinarySemaphore.h

@@ -0,0 +1,79 @@
+/*
+ * Modification History
+ *
+ * 2001-January-11		Jason Rohrer
+ * Created.
+ *
+ * 2001-January-27		Jason Rohrer
+ * Fixed a bug in the precompiler directives.
+ *
+ * 2003-August-26   Jason Rohrer
+ * Added support for timeouts on wait.
+ */
+
+#include "minorGems/common.h" 
+
+
+
+#ifndef BINARY_SEMAPHORE_CLASS_INCLUDED
+#define BINARY_SEMAPHORE_CLASS_INCLUDED
+
+#include "MutexLock.h"
+
+/**
+ * Binary semaphore class.  Semaphore starts out with a value of 0.
+ *
+ * Note:  Implementation for the functions defined here is provided
+ *   separately for each platform (in the mac/ linux/ and win32/ 
+ *   subdirectories).
+ *
+ * @author Jason Rohrer
+ */
+class BinarySemaphore {
+
+	public:
+		
+		/**
+		 * Constructs a binary semaphore.
+		 */
+		BinarySemaphore();
+		
+		~BinarySemaphore();
+		
+		
+		/**
+		 * Blocks on this semaphore until signal() is called by another thread.
+		 * Note that if signal() has already been called before wait() is
+		 * called, then this call will return immediately, though the semaphore
+		 * is reset to 0 by this call.
+         *
+         * @param inTimeoutInMilliseconds the maximum time to wait in
+         *   milliseconds, or -1 to wait forever.  Defaults to -1.
+         *
+         * @return 1 if the semaphore was signaled, or 0 if it timed out.
+		 */
+		int wait( int inTimeoutInMilliseconds = -1 );
+		
+		
+		/**
+		 * Signals the semaphore, allowing a waiting thread to return from
+		 * its call to wait(). (The semaphore is set to 1 by this call if
+		 * no thread is waiting on the semaphore currently.)
+		 */
+		void signal();
+
+
+	private:
+		
+		// starts at 0
+		int mSemaphoreValue;
+		
+		/**
+		 * Used by platform-specific implementations.
+		 */		
+		void *mNativeObjectPointerA;
+		void *mNativeObjectPointerB;
+	};
+
+
+#endif