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/*
* ZeroTier One - Network Virtualization Everywhere
* Copyright (C) 2011-2016 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
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef ZT_ATOMICCOUNTER_HPP
#define ZT_ATOMICCOUNTER_HPP
#include "Constants.hpp"
#include "Mutex.hpp"
#include "NonCopyable.hpp"
#ifdef __WINDOWS__
// <atomic> will replace this whole class eventually once it's ubiquitous
#include <atomic>
#endif
namespace ZeroTier {
/**
* Simple atomic counter supporting increment and decrement
*/
class AtomicCounter : NonCopyable
{
public:
/**
* Initialize counter at zero
*/
AtomicCounter()
throw()
{
_v = 0;
}
inline operator int() const
throw()
{
#ifdef __GNUC__
return __sync_or_and_fetch(const_cast <volatile int *>(&_v),0);
#else
#ifdef __WINDOWS__
return (int)_v;
#else
_l.lock();
int v = _v;
_l.unlock();
return v;
#endif
#endif
}
inline int operator++()
throw()
{
#ifdef __GNUC__
return __sync_add_and_fetch(&_v,1);
#else
#ifdef __WINDOWS__
return ++_v;
#else
_l.lock();
int v = ++_v;
_l.unlock();
return v;
#endif
#endif
}
inline int operator--()
throw()
{
#ifdef __GNUC__
return __sync_sub_and_fetch(&_v,1);
#else
#ifdef __WINDOWS__
return --_v;
#else
_l.lock();
int v = --_v;
_l.unlock();
return v;
#endif
#endif
}
private:
#ifdef __WINDOWS__
std::atomic_int _v;
#else
int _v;
#ifndef __GNUC__
#warning Neither __WINDOWS__ nor __GNUC__ so AtomicCounter using Mutex
Mutex _l;
#endif
#endif
};
} // namespace ZeroTier
#endif
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