count_ptr.h

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/* This file is part of Cloudy and is copyright (C)1978-2013 by Gary J. Ferland and
 * others.  For conditions of distribution and use see copyright notice in license.txt */
#ifndef COUNT_PTR_H_
#define COUNT_PTR_H_
 
#include <algorithm>
 
// Temporary stand-in for shared_ptr<> until we can rely on it being
// available as standard
template <class T>
class count_ptr {
private:
        T* m_ptr;
        long *m_count;
public:
        // Constructors
        explicit count_ptr(T* ptr = 0)
                : m_ptr(ptr), m_count(new long(1))
                {       }
        count_ptr(const count_ptr<T> &p)
                : m_ptr(p.m_ptr), m_count(p.m_count)
                {
                        ++*m_count;
                }
        ~count_ptr() throw ()
                {
                        cancel();
                }
        // Modifiers
        count_ptr<T>& operator=(count_ptr<T> temp)
                {
                        swap(temp);
                        return *this;
                }
        // Don't implement arithmetic -- would corrupt the owned pointer
        // Accessors
        T& operator*() const
                {
                        return *m_ptr;
                }
        T* operator->() const throw()
                {
                        return m_ptr;
                }
        int equiv(const count_ptr<T>& p) const throw()
                {
                        return m_ptr == p.m_ptr;
                }
        T* get_ptr() const throw()
                {
                        return m_ptr;
                }
        long count() const
                {
                        return *m_count;
                }
        void swap (count_ptr<T> &a) throw()
                {
                        std::swap(m_ptr,a.m_ptr);
                        std::swap(m_count,a.m_count);
                }
        int compare (const count_ptr<T> &a) const
                {
                        if (m_ptr < a.m_ptr)
                                return -1;
                        else if (m_ptr > a.m_ptr)
                                return 1;
                        return 0;
                }
private:
        void cancel () 
                {
                        if (0 == --*m_count)
                        {
                                delete m_count;
                                delete m_ptr;
                        }
                }
};
 
template <class T>
inline void swap (count_ptr<T> &a, count_ptr<T> &b)
{
        a.swap(b);
}
 
template <class T>
inline bool operator< (const count_ptr<T> &a, const count_ptr<T> &b)
{
        return a.compare(b) < 0;
}
template <class T>
inline bool operator> (const count_ptr<T> &a, const count_ptr<T> &b)
{
        return a.compare(b) > 0;
}
template <class T>
inline bool operator<= (const count_ptr<T> &a, const count_ptr<T> &b)
{
        return a.compare(b) <= 0;
}
template <class T>
inline bool operator>= (const count_ptr<T> &a, const count_ptr<T> &b)
{
        return a.compare(b) >= 0;
}
template <class T>
inline bool operator== (const count_ptr<T> &a, const count_ptr<T> &b)
{
        return a.compare(b) == 0;
}
template <class T>
inline bool operator!= (const count_ptr<T> &a, const count_ptr<T> &b)
{
        return !(a == b);
}
 
#endif /* COUNT_PTR_H_ */