RefCountedPtr.H

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#ifndef _REFCOUNTEDPTR_H_
#define _REFCOUNTEDPTR_H_

#include "MayDay.H"


template <class T>
class RefCountedPtr {
public:
  //
  inline RefCountedPtr(T* ptr = 0);
  //
  inline RefCountedPtr(const RefCountedPtr<T>& other);
  //
  inline ~RefCountedPtr();

  inline const RefCountedPtr<T>& operator =(const RefCountedPtr<T>& rhs);
  inline T* operator ->();
  inline const T* operator ->() const;
  //
  inline bool isNull() const;
  //
  inline T& operator *();
  inline const T& operator *() const;
  //
  inline operator const T* () const;

  inline bool isNonUnique() const;

  inline int refCount() const;

  inline void swap(RefCountedPtr<T>& b);

protected:
  T* ptr_;
  int* refCount_;
private:
};

template <class T> inline
RefCountedPtr<T>::RefCountedPtr(T* ptr)
  : ptr_(ptr),
    refCount_(0)
{
  if (ptr_)
    {
      refCount_ = new int;
      if (refCount_ == 0)
        MayDay::Error("RefCountedPtr::RefCountedPtr(T* ptr) out of memory");
      *refCount_ = 1;
    }
}

template <class T> inline
RefCountedPtr<T>::RefCountedPtr(const RefCountedPtr<T>& other)
  : ptr_(other.ptr_),
    refCount_(other.refCount_)
{
  if (refCount_ != 0)
    ++(*refCount_);
}

template <class T> inline
RefCountedPtr<T>::~RefCountedPtr() {
  if (refCount_ != 0 && --(*refCount_) == 0)
    {
      delete ptr_;
      ptr_ = 0;
      delete refCount_;
      refCount_ = 0;
    }
}

template <class T> inline
const RefCountedPtr<T>& RefCountedPtr<T>::operator =(const RefCountedPtr<T>& rhs) {
  if (ptr_ != rhs.ptr_)
    {
      if (refCount_ != 0 && --(*refCount_) == 0)
        {
          delete ptr_;
          delete refCount_;
        }
      ptr_ = rhs.ptr_;
      refCount_ = rhs.refCount_;
      if (refCount_ != 0)
        ++(*refCount_);
    }
  return *this;
}

template <class T> inline
bool RefCountedPtr<T>::isNull() const {
  return (ptr_ == 0);
}

template <class T> inline
T* RefCountedPtr<T>::operator ->() {
  if (ptr_ == 0)
    MayDay::Error("RefCountedPtr<T>::operator ->() on null pointer");
  return ptr_;
}

template <class T> inline
const T* RefCountedPtr<T>::operator ->() const {
  if (ptr_ == 0)
    MayDay::Error("RefCountedPtr<T>::operator ->() on null pointer");
  return ptr_;
}

template <class T> inline
T& RefCountedPtr<T>::operator *() {
  if (ptr_ == 0)
    MayDay::Error("RefCountedPtr<T>::operator *() on null pointer");
  return *ptr_;
}

template <class T> inline
const T& RefCountedPtr<T>::operator *() const {
  if (ptr_ == 0)
    MayDay::Error("RefCountedPtr<T>::operator *() on null pointer");
  return *ptr_;
}

template <class T> inline
RefCountedPtr<T>::operator const T* () const {
  return ptr_;
}

template <class T> inline
bool RefCountedPtr<T>::isNonUnique() const {
  return refCount_ == 0 ? false : *refCount_ != 1;
}

template <class T> inline
int RefCountedPtr<T>::refCount() const {
  return refCount_ == 0 ? 0 : *refCount_;
}

template <class T> inline
void RefCountedPtr<T>::swap(RefCountedPtr<T>& b)
{
  T* s = ptr_;
  ptr_ = b.ptr_;
  b.ptr_ = s;

  int* r = refCount_;
  refCount_ = b.refCount_;
  b.refCount_ = r;
}
#endif

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