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// Copyright (C) 2018 Intel Corporation
//
// SPDX-License-Identifier: Apache-2.0
//
#ifndef UTIL_CALL_ONCE_HPP
#define UTIL_CALL_ONCE_HPP
#include <type_traits>
#include <mutex>
namespace util
{
// Special helper for thread-safe call once per graph execution
class CallOnce
{
using Storage = typename std::aligned_storage<sizeof(std::once_flag), alignof(std::once_flag)>::type;
Storage m_flagStorage;
CallOnce(const CallOnce&) = delete;
CallOnce& operator=(const CallOnce&) = delete;
CallOnce(const CallOnce&&) = delete;
CallOnce& operator=(const CallOnce&&) = delete;
public:
CallOnce() { reset(); }
template<typename F> void operator()(F&& f)
{
std::call_once(*reinterpret_cast<std::once_flag*>(&m_flagStorage), std::forward<F>(f));
}
void reset()
{
new (&m_flagStorage) std::once_flag;
}
};
} // namespace DMIP
#endif // UTIL_CALL_ONCE_HPP
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