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144 lines
3.5 KiB
144 lines
3.5 KiB
/* |
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* ZeroTier One - Global Peer to Peer Ethernet |
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* Copyright (C) 2011-2014 ZeroTier Networks LLC |
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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 the GNU General Public License as published by |
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* the Free Software Foundation, either version 3 of the License, or |
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* (at your option) any later version. |
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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, see <http://www.gnu.org/licenses/>. |
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* |
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* -- |
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* |
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* ZeroTier may be used and distributed under the terms of the GPLv3, which |
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* are available at: http://www.gnu.org/licenses/gpl-3.0.html |
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* |
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* If you would like to embed ZeroTier into a commercial application or |
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* redistribute it in a modified binary form, please contact ZeroTier Networks |
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* LLC. Start here: http://www.zerotier.com/ |
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*/ |
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#ifndef ZT_SHAREDPTR_HPP |
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#define ZT_SHAREDPTR_HPP |
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#include "Mutex.hpp" |
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#include "AtomicCounter.hpp" |
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namespace ZeroTier { |
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/** |
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* Simple reference counted pointer |
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* |
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* This is an introspective shared pointer. Classes that need to be reference |
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* counted must list this as a 'friend' and must have a private instance of |
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* AtomicCounter called __refCount. They should also have private destructors, |
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* since only this class should delete them. |
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* |
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* Because this is introspective, it is safe to apply to a naked pointer |
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* multiple times provided there is always at least one holding SharedPtr. |
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* |
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* Once C++11 is ubiquitous, this and a few other things like Thread might get |
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* torn out for their standard equivalents. |
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*/ |
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template<typename T> |
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class SharedPtr |
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{ |
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public: |
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SharedPtr() |
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throw() : |
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_ptr((T *)0) |
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{ |
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} |
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SharedPtr(T *obj) |
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throw() : |
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_ptr(obj) |
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{ |
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++obj->__refCount; |
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} |
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SharedPtr(const SharedPtr &sp) |
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throw() : |
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_ptr(sp._getAndInc()) |
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{ |
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} |
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~SharedPtr() |
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{ |
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if (_ptr) { |
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if (--_ptr->__refCount <= 0) |
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delete _ptr; |
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} |
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} |
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inline SharedPtr &operator=(const SharedPtr &sp) |
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{ |
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if (_ptr != sp._ptr) { |
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T *p = sp._getAndInc(); |
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if (_ptr) { |
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if (--_ptr->__refCount <= 0) |
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delete _ptr; |
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} |
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_ptr = p; |
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} |
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return *this; |
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} |
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inline void swap(SharedPtr &with) |
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throw() |
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{ |
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T *tmp = _ptr; |
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_ptr = with._ptr; |
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with._ptr = tmp; |
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} |
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inline operator bool() const throw() { return (_ptr != (T *)0); } |
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inline T &operator*() const throw() { return *_ptr; } |
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inline T *operator->() const throw() { return _ptr; } |
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/** |
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* @return Raw pointer to held object |
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*/ |
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inline T *ptr() const throw() { return _ptr; } |
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/** |
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* Set this pointer to null |
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*/ |
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inline void zero() |
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{ |
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if (_ptr) { |
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if (--_ptr->__refCount <= 0) |
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delete _ptr; |
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} |
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_ptr = (T *)0; |
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} |
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inline bool operator==(const SharedPtr &sp) const throw() { return (_ptr == sp._ptr); } |
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inline bool operator!=(const SharedPtr &sp) const throw() { return (_ptr != sp._ptr); } |
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inline bool operator>(const SharedPtr &sp) const throw() { return (_ptr > sp._ptr); } |
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inline bool operator<(const SharedPtr &sp) const throw() { return (_ptr < sp._ptr); } |
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inline bool operator>=(const SharedPtr &sp) const throw() { return (_ptr >= sp._ptr); } |
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inline bool operator<=(const SharedPtr &sp) const throw() { return (_ptr <= sp._ptr); } |
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private: |
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inline T *_getAndInc() const |
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throw() |
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{ |
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if (_ptr) |
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++_ptr->__refCount; |
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return _ptr; |
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} |
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T *_ptr; |
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}; |
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} // namespace ZeroTier |
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#endif
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