// RefCount.hh for FbTk - Fluxbox Toolkit // Copyright (c) 2002 Henrik Kinnunen (fluxgen at users.sourceforge.net) // // Permission is hereby granted, free of charge, to any person obtaining a // copy of this software and associated documentation files (the "Software"), // to deal in the Software without restriction, including without limitation // the rights to use, copy, modify, merge, publish, distribute, sublicense, // and/or sell copies of the Software, and to permit persons to whom the // Software is furnished to do so, subject to the following conditions: // // The above copyright notice and this permission notice shall be included in // all copies or substantial portions of the Software. // // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL // THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER // DEALINGS IN THE SOFTWARE. #ifndef FBTK_REFCOUNT_HH #define FBTK_REFCOUNT_HH namespace FbTk { /// holds a pointer with reference counting, similar to std:auto_ptr template <typename Pointer> class RefCount { public: RefCount(); explicit RefCount(Pointer *p); explicit RefCount(RefCount<Pointer> ©); RefCount(const RefCount<Pointer> ©); ~RefCount(); RefCount<Pointer> &operator = (const RefCount<Pointer> ©); RefCount<Pointer> &operator = (Pointer *p); Pointer *operator * () const { return get(); } Pointer *operator -> () const { return get(); } Pointer *get() const { return m_data; } /// @return number of referenses unsigned int usedBy() const { return (m_refcount != 0 ? *m_refcount : 0); } private: /// increase referense count void incRefCount(); /// decrease referense count void decRefCount(); Pointer *m_data; ///< data holder mutable unsigned int *m_refcount; ///< holds reference counting }; // implementation template <typename Pointer> RefCount<Pointer>::RefCount():m_data(0), m_refcount(new unsigned int(0)) { } template <typename Pointer> RefCount<Pointer>::RefCount(RefCount<Pointer> ©): m_data(copy.m_data), m_refcount(copy.m_refcount) { incRefCount(); } template <typename Pointer> RefCount<Pointer>::RefCount(Pointer *p):m_data(p), m_refcount(new unsigned int(0)) { incRefCount(); } template <typename Pointer> RefCount<Pointer>::RefCount(const RefCount<Pointer> ©): m_data(copy.m_data), m_refcount(copy.m_refcount) { incRefCount(); } template <typename Pointer> RefCount<Pointer>::~RefCount() { decRefCount(); } template <typename Pointer> RefCount<Pointer> &RefCount<Pointer>::operator = (const RefCount<Pointer> ©) { decRefCount(); // dec current ref count m_refcount = copy.m_refcount; // set new ref count m_data = copy.m_data; // set new data pointer incRefCount(); // inc new ref count return *this; } template <typename Pointer> RefCount<Pointer> &RefCount<Pointer>::operator = (Pointer *p) { decRefCount(); m_data = p; // set data pointer m_refcount = new unsigned int(0); // create new counter incRefCount(); return *this; } template <typename Pointer> void RefCount<Pointer>::decRefCount() { if (m_refcount == 0) return; if (*m_refcount == 0) { // already zero, then delete refcount delete m_refcount; m_refcount = 0; return; } (*m_refcount)--; if (*m_refcount == 0) { // destroy m_data and m_refcount if nobody else is using this if (m_data != 0) delete m_data; m_data = 0; delete m_refcount; m_refcount = 0; } } template <typename Pointer> void RefCount<Pointer>::incRefCount() { if (m_refcount == 0) return; (*m_refcount)++; } } // end namespace FbTk #endif // FBTK_REFCOUNT_HH