nuclear@0: /************************************************************************************
nuclear@0: 
nuclear@0: PublicHeader:   OVR_Kernel.h
nuclear@0: Filename    :   OVR_Nullptr.h
nuclear@0: Content     :   Implements C++11 nullptr for the case that the compiler doesn't.
nuclear@0: Created     :   June 19, 2014
nuclear@0: Notes       : 
nuclear@0: 
nuclear@0: Copyright   :   Copyright 2014 Oculus VR, LLC All Rights reserved.
nuclear@0: 
nuclear@0: Licensed under the Oculus VR Rift SDK License Version 3.2 (the "License"); 
nuclear@0: you may not use the Oculus VR Rift SDK except in compliance with the License, 
nuclear@0: which is provided at the time of installation or download, or which 
nuclear@0: otherwise accompanies this software in either electronic or hard copy form.
nuclear@0: 
nuclear@0: You may obtain a copy of the License at
nuclear@0: 
nuclear@0: http://www.oculusvr.com/licenses/LICENSE-3.2 
nuclear@0: 
nuclear@0: Unless required by applicable law or agreed to in writing, the Oculus VR SDK 
nuclear@0: distributed under the License is distributed on an "AS IS" BASIS,
nuclear@0: WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
nuclear@0: See the License for the specific language governing permissions and
nuclear@0: limitations under the License.
nuclear@0: 
nuclear@0: ************************************************************************************/
nuclear@0: 
nuclear@0: #ifndef OVR_Nullptr_h
nuclear@0: #define OVR_Nullptr_h
nuclear@0: 
nuclear@0: #pragma once
nuclear@0: 
nuclear@0: #include "OVR_Types.h"
nuclear@0: 
nuclear@0: 
nuclear@0: //-----------------------------------------------------------------------------------
nuclear@0: // ***** OVR_HAVE_std_nullptr_t
nuclear@0: //
nuclear@0: // Identifies if <cstddef.h> includes std::nullptr_t. 
nuclear@0: //
nuclear@0: #if !defined(OVR_HAVE_std_nullptr_t) && defined(OVR_CPP11_ENABLED)
nuclear@0:     #if defined(OVR_STDLIB_LIBCPP)
nuclear@0:         #define OVR_HAVE_std_nullptr_t 1
nuclear@0:     #elif defined(OVR_STDLIB_LIBSTDCPP)
nuclear@0:         #if (__GLIBCXX__ >= 20110325) && (__GLIBCXX__ != 20110428) && (__GLIBCXX__ != 20120702)
nuclear@0:             #define OVR_HAVE_std_nullptr_t 1
nuclear@0:         #endif
nuclear@0:     #elif defined(_MSC_VER) && (_MSC_VER >= 1600) // VS2010+
nuclear@0:         #define OVR_HAVE_std_nullptr_t 1
nuclear@0:     #elif defined(__clang__)
nuclear@0:         #define OVR_HAVE_std_nullptr_t 1
nuclear@0:     #elif defined(OVR_CPP_GNUC) && (OVR_CC_VERSION >= 406) // GCC 4.6+
nuclear@0:         #define OVR_HAVE_std_nullptr_t 1
nuclear@0:     #endif
nuclear@0: #endif
nuclear@0: 
nuclear@0: 
nuclear@0: //-----------------------------------------------------------------------------------
nuclear@0: // ***** nullptr / std::nullptr_t
nuclear@0: //
nuclear@0: // Declares and defines nullptr and related types.
nuclear@0: //
nuclear@0: #if defined(OVR_CPP_NO_NULLPTR)
nuclear@0:     namespace std
nuclear@0:     {
nuclear@0:         class nullptr_t
nuclear@0:         {
nuclear@0:         public:
nuclear@0:             template <typename T>
nuclear@0:             operator T*() const
nuclear@0:                 { return 0; }
nuclear@0:          
nuclear@0:             template <typename C, typename T>
nuclear@0:             operator T C::*() const
nuclear@0:                 { return 0; }
nuclear@0: 
nuclear@0:             #if OVR_CPP_NO_EXPLICIT_CONVERSION_OPERATORS
nuclear@0:                 typedef void* (nullptr_t::*bool_)() const;  // 4.12,p1. We can't portably use operator bool(){ return false; } because bool 
nuclear@0:                 operator bool_() const                      // is convertable to int which breaks other required functionality.
nuclear@0:                     { return false; }
nuclear@0:             #else
nuclear@0:                 operator bool() const
nuclear@0:                     { return false; }
nuclear@0:             #endif
nuclear@0: 
nuclear@0:         private:
nuclear@0:             void operator&() const; // 5.2.10,p9
nuclear@0:         };
nuclear@0: 
nuclear@0:         inline nullptr_t nullptr_get()
nuclear@0:         {
nuclear@0:             nullptr_t n = { };
nuclear@0:             return n;
nuclear@0:         }
nuclear@0: 
nuclear@0:         #if !defined(nullptr)
nuclear@0:             #define nullptr nullptr_get()
nuclear@0:         #endif
nuclear@0: 
nuclear@0:     } // namespace std
nuclear@0: 
nuclear@0: 
nuclear@0:     // 5.9,p2 p4
nuclear@0:     // 13.6, p13
nuclear@0:     template <typename T>
nuclear@0:     inline bool operator==(T* pT, const std::nullptr_t)
nuclear@0:         { return pT == 0; }
nuclear@0: 
nuclear@0:     template <typename T>
nuclear@0:     inline bool operator==(const std::nullptr_t, T* pT)
nuclear@0:         { return pT == 0; }
nuclear@0: 
nuclear@0:     template <typename T, typename U>
nuclear@0:     inline bool operator==(const std::nullptr_t, T U::* pU)
nuclear@0:         { return pU == 0; }
nuclear@0: 
nuclear@0:     template <typename T, typename U>
nuclear@0:     inline bool operator==(T U::* pTU, const std::nullptr_t)
nuclear@0:         { return pTU == 0; }
nuclear@0: 
nuclear@0:     inline bool operator==(const std::nullptr_t, const std::nullptr_t)
nuclear@0:         { return true; }
nuclear@0: 
nuclear@0:     inline bool operator!=(const std::nullptr_t, const std::nullptr_t)
nuclear@0:         { return false; }
nuclear@0: 
nuclear@0:     inline bool operator<(const std::nullptr_t, const std::nullptr_t)
nuclear@0:         { return false; }
nuclear@0: 
nuclear@0:     inline bool operator<=(const std::nullptr_t, const std::nullptr_t)
nuclear@0:         { return true; }
nuclear@0: 
nuclear@0:     inline bool operator>(const std::nullptr_t, const std::nullptr_t)
nuclear@0:         { return false; }
nuclear@0: 
nuclear@0:     inline bool operator>=(const std::nullptr_t, const std::nullptr_t)
nuclear@0:         { return true; }
nuclear@0: 
nuclear@0:     using std::nullptr_t;
nuclear@0:     using std::nullptr_get;
nuclear@0: 
nuclear@0: // Some compilers natively support C++11 nullptr but the standard library being used 
nuclear@0: // doesn't declare std::nullptr_t, in which case we provide one ourselves.
nuclear@0: #elif !defined(OVR_HAVE_std_nullptr_t) && !defined(OVR_CPP_NO_DECLTYPE)
nuclear@0:     namespace std { typedef decltype(nullptr) nullptr_t; }
nuclear@0: #endif
nuclear@0: 
nuclear@0: 
nuclear@0: #endif
nuclear@0: