00001 00002 #ifndef _REF_COUNTER_H_ 00003 #define _REF_COUNTER_H_ 00004 00005 00006 #pragma warning(disable:4786) 00007 00008 00009 class RefCounter { 00010 00011 public: 00012 00014 // // 00015 // Exported Type Handles // 00016 // // 00018 00019 typedef unsigned int refCounterType; 00020 00022 // // 00023 // Constructors // 00024 // // 00026 00027 RefCounter( ) : xrefs(0) { } 00028 // a new reference counter is initialised 00029 // with a ref count of 1 (ie 0 extra refs) 00030 00031 RefCounter( const RefCounter& rc ) : xrefs(0) { } 00032 // for derived representation classes whose copy constructor is generated 00033 // by the compiler: a new (copied) representation also has an initial 00034 // extra ref count of 0 00035 00036 // Destructor provided by compiler 00037 00039 // // 00040 // Reference Count Handles // 00041 // // 00043 00044 bool lastRef( ) const { return xrefs == 0; } 00045 00046 bool sharedRef( ) const { return xrefs != 0; } 00047 00048 void addRef( ) const { ++((RefCounter*)this)->xrefs; } 00049 // addRef is logically const 00050 00051 void delRef( ) const { --((RefCounter*)this)->xrefs; } 00052 // delRef is logically const 00053 00054 #ifdef DEBUG 00055 refCounterType nxrefs( ) const { return xrefs; } 00056 #endif 00057 00058 private: 00059 00061 // // 00062 // Data Members // 00063 // // 00065 00066 refCounterType xrefs; // extra references (ie 0 means one ref) 00067 00069 // // 00070 // Hidden Members // 00071 // // 00073 00074 RefCounter& operator = ( const RefCounter& ); 00075 // disable assignment: normally representations are never assigned 00076 00077 }; 00078 00079 #endif 00080
1.6.1
