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// Build don't link:
// GROUPS passed old-abort
const int TRUE = 1;
const int FALSE = 0;
class Rep {
protected:
Rep(): count(0)
{ }
Rep(const Rep& other): count(0)
{ }
Rep& operator=(const Rep& other)
{ /* DO NOT copy over other.count */
return *this; }
public: // TODO - for now
// Because it is to hard to restrict these operations to the descendants
// of Rep<REP> that we haven't named yet. So we just make them public.
void inc()
{ count++; }
void dec()
{ if (0 == --count) delete this; }
private:
unsigned count;
};
template<class REP>
class Ref {
public:
Ref(): rep(0)
{ }
Ref(const Ref<REP>& other): rep(other.rep)
{ if (rep) rep->inc(); }
~Ref()
{ if (rep) rep->dec();
rep = 0; }
Ref<REP>& operator=(const Ref<REP>& other)
{ if (rep != other.rep) {
if (rep) rep->dec();
rep = other.rep;
if (rep) rep->inc(); }
return *this; }
bool null() const
{ return 0 == rep ? TRUE: FALSE; }
bool valid() const
{ return 0 != rep ? TRUE: FALSE; }
REP* operator->() const // should be a valid() reference
{ return rep; }
operator REP*() const; // should be a valid() reference
protected:
REP *rep;
Ref(REP *r): rep(r)
{ if (rep) rep->inc(); }
Ref<REP>& operator=(REP *r)
{ if (rep != r) {
if (rep) rep->dec();
rep = r;
if (rep) rep->inc(); }
return *this; }
};
template<class REP>
Ref<REP>::operator REP*() const // should be a valid() reference
{ return rep; }
template<class REP>
inline int
operator==(const Ref<REP>& a, const Ref<REP>& b)
{ return (REP *) a == (REP *) b; }
template<class REP>
inline int
operator!=(const Ref<REP>& a, const Ref<REP>& b)
{ return (REP *) a != (REP *) b; }
class XRep: public Rep {
public:
int i;
};
main()
{
Ref<XRep> y;
return y != y;
}
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