ZeroTierOne/node/AtomicCounter.hpp

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/*
* ZeroTier One - Network Virtualization Everywhere
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* Copyright (C) 2011-2019 ZeroTier, Inc. https://www.zerotier.com/
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* 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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*
* --
*
* You can be released from the requirements of the license by purchasing
* a commercial license. Buying such a license is mandatory as soon as you
* develop commercial closed-source software that incorporates or links
* directly against ZeroTier software without disclosing the source code
* of your own application.
*/
#ifndef ZT_ATOMICCOUNTER_HPP
#define ZT_ATOMICCOUNTER_HPP
#include "Constants.hpp"
#ifndef __GNUC__
#include <atomic>
#endif
namespace ZeroTier {
/**
* Simple atomic counter supporting increment and decrement
*/
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class AtomicCounter
{
public:
inline AtomicCounter() { _v = 0; }
inline int load() const
{
#ifdef __GNUC__
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return __sync_or_and_fetch(const_cast<int *>(&_v),0);
#else
return _v.load();
#endif
}
inline int operator++()
{
#ifdef __GNUC__
return __sync_add_and_fetch(&_v,1);
#else
return ++_v;
#endif
}
inline int operator--()
{
#ifdef __GNUC__
return __sync_sub_and_fetch(&_v,1);
#else
return --_v;
#endif
}
private:
inline AtomicCounter(const AtomicCounter &) {}
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const AtomicCounter &operator=(const AtomicCounter &) { return *this; }
#ifdef __GNUC__
int _v;
#else
std::atomic_int _v;
#endif
};
} // namespace ZeroTier
#endif