Added nullptr definition

nullptr.h

@@ -0,0 +1,74 @@
+///\file
+
+/******************************************************************************
+The MIT License(MIT)
+
+Embedded Template Library.
+
+Copyright(c) 2014 jwellbelove
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files(the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions :
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+******************************************************************************/
+
+#ifndef __etl_nullptr__
+#define __etl_nullptr__
+
+///\defgroup nullptr nullptr
+/// A definition of nullptr for compilers that don't support it as standard.
+///\ingroup utilities
+
+namespace etl
+{
+  //*****************************************************************************
+  /// A null pointer type.
+  ///\ingroup nullptr
+  //*****************************************************************************
+  class nullptr_t
+  {
+  public:
+
+    // Convertible to any type of null non-member pointer.
+    template<class T>
+    inline operator T*() const
+    {
+      return 0;
+    }
+
+    // Or any type of null member pointer.
+    template<class C, class T>
+    inline operator T C::*() const
+    {
+      return 0;
+    }
+
+  private:
+
+    // Can't take address of nullptr.
+    void operator&() const;
+  };
+
+  //*****************************************************************************
+  /// A null pointer.
+  ///\ingroup nullptr
+  //*****************************************************************************
+  const nullptr_t nullptr = {};
+}
+
+#endif
+