ASTRefCount.hpp

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#ifndef INC_ASTRefCount_hpp__
# define INC_ASTRefCount_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/ASTRefCount.hpp#2 $
 */
 
# include <antlr/config.hpp>
 
#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
namespace antlr {
#endif
 
   class AST;
 
struct ANTLR_API ASTRef
{
   AST* const ptr;
   unsigned int count;
 
   ASTRef(AST* p);
   ~ASTRef();
   ASTRef* increment()
   {
      ++count;
      return this;
   }
   bool decrement()
   {
      return (--count==0);
   }
 
   static ASTRef* getRef(const AST* p);
private:
   ASTRef( const ASTRef& );
   ASTRef& operator=( const ASTRef& );
};
 
template<class T>
   class ANTLR_API ASTRefCount
{
private:
   ASTRef* ref;
 
public:
   ASTRefCount(const AST* p=0)
   : ref(p ? ASTRef::getRef(p) : 0)
   {
   }
   ASTRefCount(const ASTRefCount<T>& other)
   : ref(other.ref ? other.ref->increment() : 0)
   {
   }
   ~ASTRefCount()
   {
      if (ref && ref->decrement())
         delete ref;
   }
   ASTRefCount<T>& operator=(AST* other)
   {
      ASTRef* tmp = ASTRef::getRef(other);
 
      if (ref && ref->decrement())
         delete ref;
 
      ref=tmp;
 
      return *this;
   }
   ASTRefCount<T>& operator=(const ASTRefCount<T>& other)
   {
      if( other.ref != ref )
      {
         ASTRef* tmp = other.ref ? other.ref->increment() : 0;
 
         if (ref && ref->decrement())
            delete ref;
 
         ref=tmp;
      }
      return *this;
   }
 
   operator T* ()  const { return ref ? static_cast<T*>(ref->ptr) : 0; }
   T* operator->() const { return ref ? static_cast<T*>(ref->ptr) : 0; }
   T* get()        const { return ref ? static_cast<T*>(ref->ptr) : 0; }
};
 
typedef ASTRefCount<AST> RefAST;
 
#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
}
#endif
 
#endif //INC_ASTRefCount_hpp__