[base] Move container_of to own file

base/container_of.h

@@ -0,0 +1,24 @@
+#ifndef BASE_CONTAINER_OF_H
+#define BASE_CONTAINER_OF_H
+
+#include <stdlib.h>
+
+//----------------------------------------------------------------
+
+namespace base {
+	template<class P, class M>
+	size_t offsetof__(const M P::*member)
+	{
+		return (size_t) &( reinterpret_cast<P*>(0)->*member);
+	}
+
+	template<class P, class M>
+	P *container_of(M *ptr, M const P::*member)
+	{
+		return (P *)((char *)(ptr) - offsetof__(member));
+	}
+}
+
+//----------------------------------------------------------------
+
+#endif