100 lines
2.1 KiB
C++
100 lines
2.1 KiB
C++
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#ifndef REFPTR_H
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#define REFPTR_H REFPTR_H
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/* Author: Josh Holtrop
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* Purpose: Provide a reference-counting pointer-like first order
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* C++ object that will free the object it is pointing to when
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* all references to it have been destroyed.
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* This implementation does not solve the circular reference problem.
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* I was not concerned with that when developing this class.
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*/
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#include <stdlib.h> /* NULL */
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template <typename T>
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class refptr
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{
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public:
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refptr<T>();
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refptr<T>(T * ptr);
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refptr<T>(const refptr<T> & orig);
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refptr<T> & operator=(const refptr<T> & orig);
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refptr<T> & operator=(T * ptr);
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~refptr<T>();
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T & operator*() const { return *m_ptr; }
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T * operator->() const { return m_ptr; }
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bool isNull() const { return m_ptr == NULL; }
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private:
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void cloneFrom(const refptr<T> & orig);
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void destroy();
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T * m_ptr;
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int * m_refCount;
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};
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template <typename T> refptr<T>::refptr()
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{
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m_ptr = NULL;
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m_refCount = NULL;
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}
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template <typename T> refptr<T>::refptr(T * ptr)
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{
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m_ptr = ptr;
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m_refCount = new int;
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*m_refCount = 1;
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}
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template <typename T> refptr<T>::refptr(const refptr<T> & orig)
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{
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cloneFrom(orig);
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}
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template <typename T> refptr<T> & refptr<T>::operator=(const refptr<T> & orig)
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{
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destroy();
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cloneFrom(orig);
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return *this;
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}
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template <typename T> refptr<T> & refptr<T>::operator=(T * ptr)
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{
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destroy();
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m_ptr = ptr;
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m_refCount = new int;
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*m_refCount = 1;
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return *this;
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}
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template <typename T> void refptr<T>::cloneFrom(const refptr<T> & orig)
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{
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this->m_ptr = orig.m_ptr;
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this->m_refCount = orig.m_refCount;
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if (m_refCount != NULL)
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(*m_refCount)++;
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}
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template <typename T> refptr<T>::~refptr()
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{
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destroy();
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}
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template <typename T> void refptr<T>::destroy()
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{
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if (m_refCount != NULL)
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{
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if (*m_refCount <= 1)
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{
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delete m_ptr;
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delete m_refCount;
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}
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else
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{
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(*m_refCount)--;
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}
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}
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}
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#endif
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