first commit

include/platform/memory/nshared_ptr.h

@@ -0,0 +1,150 @@
+/* -----------------------------------------------------------------------------
+	GSFramework
+	Copyright 2001-2013 Emmanuel Julien. All Rights Reserved.
+----------------------------------------------------------------------------- */
+
+
+#ifndef	__NSHARED_PTR__
+#define __NSHARED_PTR__
+
+
+		#include "thread/atomic_value.h"
+
+
+namespace GS {
+
+/// Weak reference to a shared object.
+class	WeakRef
+{
+		friend class SharedObject;
+
+		bool		is_valid;
+		Threading::Atomic32 refc;
+
+		WeakRef() : is_valid(true) {}
+
+public:
+
+		bool		IsValid() const { return is_valid; }
+
+		int			GetRefCount() const { return refc.Get(); }
+
+		void		AddRef() { refc.Inc(); }
+		void		RemoveRef()
+		{
+			if	((refc.Dec() == 0) && !is_valid)
+				delete this;
+		}
+};
+
+/*!
+	@short	Reference counted object.
+	@author	Emmanuel Julien (ejulien@gsworks.fr)
+*/
+class	SharedObject
+{
+		Threading::Atomic32 refc;
+		WeakRef		*weak_ref;
+
+protected:
+
+virtual	~SharedObject()
+		{
+			if	(weak_ref)
+			{
+				if	(weak_ref->refc.Get() == 0)
+					delete weak_ref;
+				else
+					weak_ref->is_valid = false;
+			}
+		}
+
+public:
+
+		WeakRef		*GetWeakRef()
+		{
+			if	(!weak_ref)
+				weak_ref = new WeakRef;		// TODO have a specialized, fixed pool allocator for these.
+			return weak_ref;
+		}
+
+		int			GetRefCount() const { return refc.Get(); }
+
+		void		AddRef() { refc.Inc(); }
+		void		RemoveRef()
+		{
+			if	(refc.Dec() == 0)
+			{
+				if	(weak_ref)
+					weak_ref->is_valid = false;
+				delete this;
+			}
+		}
+
+		SharedObject() : weak_ref(0) {}
+};
+
+/*!
+	@short	Strong smart pointer to a reference counted object.
+	@author	Emmanuel Julien (ejulien@gsworks.fr)
+*/
+template <class T> class SharedPtr
+{
+		T			*rc_o;
+
+public:
+
+inline	operator T	*() const { return rc_o; }
+inline	T			*c_ptr() const { return rc_o; }
+
+inline	bool		IsNull() const { return rc_o ? false : true; }
+inline	bool		IsValid() const { return rc_o ? true : false; }
+
+		void		Init()
+		{
+			if	(rc_o)
+				rc_o->AddRef();
+		}
+
+inline	bool		operator == (const T *p) const { return rc_o == p; }
+inline	bool		operator != (const T *p) const { return rc_o != p; }
+inline	bool		operator == (T *p) const { return rc_o == p; }
+inline	bool		operator != (T *p) const { return rc_o != p; }
+
+inline	bool		operator == (const SharedPtr &p) const { return rc_o == p.rc_o; }
+inline	bool		operator != (const SharedPtr &p) const { return rc_o != p.rc_o; }
+
+		T			*operator = (T *p)
+		{
+			if	(rc_o != p)
+			{
+				if	(rc_o)
+					rc_o->RemoveRef();
+				rc_o = p;
+				Init();
+			}
+			return p;
+		}
+		SharedPtr <T> &operator = (const SharedPtr &p)
+		{
+			*this = p.c_ptr();
+			return *this;
+		}
+inline	T			*operator -> () const { return rc_o; }
+inline	T			&operator * () const { return *rc_o; }
+
+		explicit SharedPtr(T *p) : rc_o(p) { Init(); }
+		SharedPtr(const SharedPtr &p) : rc_o(p.rc_o) { Init(); }
+		SharedPtr() : rc_o(0) {}
+
+		~SharedPtr()
+		{
+			if	(rc_o)
+				rc_o->RemoveRef();
+		}
+};
+
+} // GS
+
+
+#endif	// __NSHARED_PTR__