RefCount.hpp

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#ifndef INC_RefCount_hpp__
#define INC_RefCount_hpp__
/* ANTLR Translator Generator
 * Project led by Terence Parr at http://www.jGuru.com
 * Software rights: http://www.antlr.org/license.html
 *
 * $Id: //depot/code/org.antlr/release/antlr-2.7.7/lib/cpp/antlr/RefCount.hpp#2 $
 */
 
#include <antlr/config.hpp>
 
#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
namespace antlr {
#endif
 
template<class T>
class ANTLR_API RefCount {
private:
   struct Ref {
      T* const ptr;
      unsigned int count;
 
      Ref(T* p) : ptr(p), count(1) {}
      ~Ref() {delete ptr;}
      Ref* increment() {++count;return this;}
      bool decrement() {return (--count==0);}
   private:
      Ref(const Ref&);
      Ref& operator=(const Ref&);
   }* ref;
 
public:
   explicit RefCount(T* p = 0)
   : ref(p ? new Ref(p) : 0)
   {
   }
   RefCount(const RefCount<T>& other)
   : ref(other.ref ? other.ref->increment() : 0)
   {
   }
   ~RefCount()
   {
      if (ref && ref->decrement())
         delete ref;
   }
   RefCount<T>& operator=(const RefCount<T>& other)
   {
      Ref* tmp = other.ref ? other.ref->increment() : 0;
      if (ref && ref->decrement())
         delete ref;
      ref = tmp;
      return *this;
   }
 
   operator T* () const
   {
      return ref ? ref->ptr : 0;
   }
 
   T* operator->() const
   {
      return ref ? ref->ptr : 0;
   }
 
   T* get() const
   {
      return ref ? ref->ptr : 0;
   }
 
   template<class newType> operator RefCount<newType>()
   {
      return RefCount<newType>(ref);
   }
};
 
#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
}
#endif
 
#endif //INC_RefCount_hpp__