ZeroTierOne/node/AtomicCounter.hpp

/*
 * Copyright (c)2019 ZeroTier, Inc.
 *
 * Use of this software is governed by the Business Source License included
 * in the LICENSE.TXT file in the project's root directory.
 *
 * Change Date: 2026-01-01
 *
 * On the date above, in accordance with the Business Source License, use
 * of this software will be governed by version 2.0 of the Apache License.
 */
/****/

#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
 */
class AtomicCounter {
  public:
	AtomicCounter()
	{
		_v = 0;
	}

	inline int load() const
	{
#ifdef __GNUC__
		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:
	AtomicCounter(const AtomicCounter&)
	{
	}
	const AtomicCounter& operator=(const AtomicCounter&)
	{
		return *this;
	}

#ifdef __GNUC__
	int _v;
#else
	std::atomic_int _v;
#endif
};

}	// namespace ZeroTier

#endif