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//
// immer: immutable data structures for C++
// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
//
// This software is distributed under the Boost Software License, Version 1.0.
// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
//
#pragma once
#include <atomic>
namespace immer {
namespace detail {
template <typename Deriv>
struct ref_count_base
{
mutable std::atomic<int> ref_count{0};
friend void intrusive_ptr_add_ref(const Deriv* x)
{
x->ref_count.fetch_add(1, std::memory_order_relaxed);
}
friend void intrusive_ptr_release(const Deriv* x)
{
if (x->ref_count.fetch_sub(1, std::memory_order_release) == 1) {
std::atomic_thread_fence(std::memory_order_acquire);
delete x;
}
}
};
} /* namespace detail */
} /* namespace immer */
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