Current File : //usr/include/mysql/server/private/my_counter.h
#ifndef MY_COUNTER_H_INCLUDED
#define MY_COUNTER_H_INCLUDED
/*
Copyright (C) 2018 MariaDB Foundation
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; version 2 of the License.
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, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <atomic>
template <typename Type> class Atomic_counter
{
std::atomic<Type> m_counter;
Type add(Type i) { return m_counter.fetch_add(i, std::memory_order_relaxed); }
Type sub(Type i) { return m_counter.fetch_sub(i, std::memory_order_relaxed); }
public:
Atomic_counter(const Atomic_counter<Type> &rhs)
{ m_counter.store(rhs, std::memory_order_relaxed); }
Atomic_counter(Type val): m_counter(val) {}
Atomic_counter() = default;
Type operator++(int) { return add(1); }
Type operator--(int) { return sub(1); }
Type operator++() { return add(1) + 1; }
Type operator--() { return sub(1) - 1; }
Type operator+=(const Type i) { return add(i) + i; }
Type operator-=(const Type i) { return sub(i) - i; }
operator Type() const { return m_counter.load(std::memory_order_relaxed); }
Type operator=(const Type val)
{ m_counter.store(val, std::memory_order_relaxed); return val; }
};
#endif /* MY_COUNTER_H_INCLUDED */
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