Cross Platform Development SDK Game

00001 
00002 // 
00003 // File..............: sgSingleton.h
00004 // Author............: Luis Sempe
00005 // Created on........: Sunday, July 13, 2003
00006 // 
00007 // Sphere Games Copyright (C) 2003
00008 // All rights reserved.
00009 // 
00010 //                C O N F I D E N T I A L                  
00011 // 
00013 
00014 #ifndef SGSINGLETON_H_
00015 #define SGSINGLETON_H_
00016 
00017 #include <cassert>
00018 
00019 /*
00020 Example usage:
00021 
00022 class StateManager : public Singleton <StateManager>
00023 {
00024 // ...
00025 State* GetState() { return &State; }
00026 }
00027 
00028 State = StateManager::Get()->GetState();
00029 
00030 Also, it's possible to do:
00031 
00032 #define STATEMANAGER (StateManager::Get())
00033 
00034 and then reference the statemanager like this:
00035 
00036 STATEMANAGER->GetState();
00037 
00038 Finally, do not forget to create the StateManager as a static global or with new. Either way
00039 you do it, it has to be done before using StateManager::Get() otherwise, bad things occur.
00040 */
00041 #ifdef _WIN32
00042 #pragma warning( push )
00043 #pragma warning( disable:4311 ) // 'variable' : pointer truncation from 'type' to 'type'
00044 #pragma warning( disable:4312 ) // 'variable' : conversion from 'type' to 'type' of greater size
00045 #endif
00046 
00047 template <typename T>
00048 class Singleton
00049 {
00050         static T*       m_pInstance;    
00051 public:
00052 
00053         Singleton() 
00054         {
00055                 assert( !m_pInstance );
00056                 int offset = reinterpret_cast<int>( reinterpret_cast<T*>( 0x1 ) ) -  reinterpret_cast<int>( reinterpret_cast< Singleton<T>* >( reinterpret_cast<T*>( 0x1 ) ) );
00057                 m_pInstance = reinterpret_cast<T*>(reinterpret_cast<int>(this) + offset);               
00058         }
00059 
00060         virtual ~Singleton()
00061         {
00062                 assert(m_pInstance);
00063                 m_pInstance = 0;                
00064         }
00065 
00066         static T& Get() { assert(m_pInstance); return *m_pInstance; }
00067         static T* GetPtr() { assert(m_pInstance); return m_pInstance; }
00068 
00069 private:
00070 
00071         Singleton(const Singleton&) {}
00072 //      Singleton& operator = (const Singleton&) { return }
00073 
00074 };
00075 
00076 template <typename T> T* Singleton <T>::m_pInstance = 0;
00077 
00078 #ifdef _WIN32
00079 #pragma warning(pop)
00080 #endif
00081 
00082 
00083 #endif
lua_Singleton.h
