102 lines
3 KiB
C++
102 lines
3 KiB
C++
/*
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* Copyright (C) 2005 Maarten Keijzer
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of version 2 of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef _SHARED_PTR_H
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#define _SHARED_PTR_H
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template <class T> class weak_ptr;
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template <class T>
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class shared_ptr {
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private:
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T* ptr;
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unsigned* count; //
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/* special case, null pointer (nil-code) */
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static unsigned* nil() { static unsigned nil_counter(1); return &nil_counter; }
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void decref() { if (--(*count) == 0) { delete ptr; delete count; }}
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void incref() { ++(*count); }
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friend class weak_ptr<T>;
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public:
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shared_ptr() : ptr(0), count(nil()) { incref(); }
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~shared_ptr() { decref(); }
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shared_ptr(const shared_ptr<T>& o) : ptr(o.ptr), count(o.count) { incref(); }
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shared_ptr(T* p) : ptr(p), count(new unsigned(1)) {}
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explicit shared_ptr(const weak_ptr<T>& w) : ptr(w.ptr), count(w.count) { incref(); }
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shared_ptr<T>& operator=(const shared_ptr<T>& o) {
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if (ptr == o.ptr) return *this;
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decref();
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ptr = o.ptr;
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count = o.count;
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incref();
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return *this;
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}
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T* get() { return ptr; }
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T* operator->() { return ptr; }
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T& operator*() { return *ptr; }
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const T* get() const { return ptr; }
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const T* operator->() const { return ptr; }
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const T& operator*() const { return *ptr; }
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bool operator==(const shared_ptr<T>& o) const { return ptr == o.ptr; }
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bool operator!=(const shared_ptr<T>& o) const { return ptr != o.ptr; }
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bool operator<(const shared_ptr<T>& o) const { return ptr < o.ptr; }
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unsigned refcount() const { return *count; }
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};
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template <class T>
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class weak_ptr {
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T* ptr;
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unsigned* count;
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friend class shared_ptr<T>;
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public:
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weak_ptr() : ptr(0), count(shared_ptr<T>::nil()) {}
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explicit weak_ptr( const shared_ptr<T>& s) : ptr(s.ptr), count(s.count) {}
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shared_ptr<T> lock() const { return shared_ptr<T>(*this); }
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T* get() { return ptr; }
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T* operator->() { return ptr; }
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T& operator*() { return *ptr; }
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const T* get() const { return ptr; }
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const T* operator->() const { return ptr; }
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const T& operator*() const { return *ptr; }
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bool operator==(const shared_ptr<T>& o) const { return ptr == o.ptr; }
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bool operator!=(const shared_ptr<T>& o) const { return ptr != o.ptr; }
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bool operator<(const shared_ptr<T>& o) const { return ptr < o.ptr; }
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unsigned refcount() const { return *count; }
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};
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#endif
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