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105 lines
2.5 KiB
C++
105 lines
2.5 KiB
C++
/**
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* \file libconcur/element.h
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* \author mutouyun (orz@orzz.org)
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* \brief Define concurrent queue element abstraction.
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* \date 2022-11-19
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*/
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#pragma once
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#include <atomic>
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#include <utility>
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#include <cstdint>
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#include <exception>
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#include "libimp/detect_plat.h"
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#include "libimp/log.h"
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#include "libimp/byte.h"
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#include "libimp/generic.h"
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#include "libconcur/def.h"
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LIBCONCUR_NAMESPACE_BEG_
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namespace state {
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/// \typedef The state flag type for the queue element.
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using flag_t = std::uint64_t;
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enum : flag_t {
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invalid_value = ~flag_t(0),
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enqueue_mask = invalid_value << 32,
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commit_mask = ~flag_t(1) << 32,
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};
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} // namespace state
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/// \brief Define the padding type.
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template <typename T>
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using padding = std::array<::LIBIMP::byte, (cache_line_size - sizeof(T))>;
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/**
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* \class template <typename T> element
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* \brief User-defined type element wrapper.
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* Wrapper for wrapping user-defined types as elements.
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*
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* @tparam T - User-defined type.
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*/
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template <typename T>
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class element {
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template <typename E>
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friend auto get(E &&elem) noexcept;
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/// \brief Committed flag.
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std::atomic<state::flag_t> f_ct_;
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padding<decltype(f_ct_)> ___;
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/// \brief The user data segment.
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T data_;
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/// \brief Disable copy & move.
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element(element const &) = delete;
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element &operator=(element const &) = delete;
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public:
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using value_type = T;
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template <typename... A>
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element(A &&... args)
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noexcept(noexcept(T{std::forward<A>(args)...}))
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: f_ct_{state::invalid_value}
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, data_{std::forward<A>(args)...} {}
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template <typename U>
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void set_data(U &&src) noexcept {
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LIBIMP_LOG_();
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LIBIMP_TRY {
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data_ = std::forward<U>(src);
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} LIBIMP_CATCH(std::exception const &e) {
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log.error("failed: `data = std::forward<U>(src)`. error = ", e.what());
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} LIBIMP_CATCH(...) {
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log.error("failed: `data = std::forward<U>(src)`. error = unknown");
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}
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}
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void set_flag(state::flag_t flag,
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std::memory_order const order = std::memory_order_release) noexcept {
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f_ct_.store(flag, order);
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}
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bool cas_flag(state::flag_t &expected, state::flag_t flag,
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std::memory_order const order = std::memory_order_acq_rel) noexcept {
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return f_ct_.compare_exchange_weak(expected, flag, order);
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}
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state::flag_t get_flag() const noexcept {
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return f_ct_.load(std::memory_order_acquire);
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}
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};
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template <typename E>
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auto get(E &&elem) noexcept {
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return static_cast<imp::copy_cvref_t<E, typename std::decay<E>::type::value_type>>(elem.data_);
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}
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LIBCONCUR_NAMESPACE_END_
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