antlr/include/antlr/TokenRefCount.hpp

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#ifndef INC_TokenRefCount_hpp__
# define INC_TokenRefCount_hpp__

/* ANTLR Translator Generator
 * Project led by Terence Parr at http://www.jGuru.com
 * Software rights: http://www.antlr.org/license.html
 *
 * $Id:$
 */

# include <antlr/config.hpp>

#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
namespace antlr {
#endif

class Token;

struct ANTLR_API TokenRef
{
        Token* const ptr;
        unsigned int count;

        TokenRef(Token* p);
        ~TokenRef();
        TokenRef* increment()
        {
                ++count;
                return this;
        }
        bool decrement()
        {
                return (--count==0);
        }

        static TokenRef* getRef(const Token* p);
private:
        TokenRef( const TokenRef& );
        TokenRef& operator=( const TokenRef& );
};

template<class T>
        class ANTLR_API TokenRefCount
{
private:
        TokenRef* ref;

public:
        TokenRefCount(const Token* p=0)
        : ref(p ? TokenRef::getRef(p) : 0)
        {
        }
        TokenRefCount(const TokenRefCount<T>& other)
        : ref(other.ref ? other.ref->increment() : 0)
        {
        }
        ~TokenRefCount()
        {
                if (ref && ref->decrement())
                        delete ref;
        }
        TokenRefCount<T>& operator=(Token* other)
        {
                TokenRef* tmp = TokenRef::getRef(other);

                if (ref && ref->decrement())
                        delete ref;

                ref=tmp;

                return *this;
        }
        TokenRefCount<T>& operator=(const TokenRefCount<T>& other)
        {
                if( other.ref != ref )
                {
                        TokenRef* 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 TokenRefCount<Token> RefToken;

#ifdef ANTLR_CXX_SUPPORTS_NAMESPACE
}
#endif

#endif //INC_TokenRefCount_hpp__

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