整理

2026-03-23 20:54:41 +08:00
commit e13b3650e9
4596 changed files with 1015768 additions and 0 deletions
--- a/include/boost/atomic/detail/chrono.hpp
+++ b/include/boost/atomic/detail/chrono.hpp
@@ -0,0 +1,93 @@
+/*
+ * Distributed under the Boost Software License, Version 1.0.
+ * (See accompanying file LICENSE_1_0.txt or copy at
+ * http://www.boost.org/LICENSE_1_0.txt)
+ *
+ * Copyright (c) 2025 Andrey Semashev
+ */
+/*!
+ * \file   atomic/detail/chrono.hpp
+ *
+ * This header contains \c std::chrono utilities.
+ */
+
+#ifndef BOOST_ATOMIC_DETAIL_CHRONO_HPP_INCLUDED_
+#define BOOST_ATOMIC_DETAIL_CHRONO_HPP_INCLUDED_
+
+#include <time.h>
+#include <chrono>
+#if !defined(__cpp_lib_chrono) || (__cpp_lib_chrono < 201510l)
+#include <ratio>
+#include <type_traits>
+#endif // !defined(__cpp_lib_chrono) || (__cpp_lib_chrono < 201510l)
+#if defined(CLOCK_REALTIME)
+#include <boost/atomic/posix_clock_traits_fwd.hpp>
+#endif // defined(CLOCK_REALTIME)
+#include <boost/atomic/detail/config.hpp>
+#include <boost/atomic/detail/header.hpp>
+
+#ifdef BOOST_HAS_PRAGMA_ONCE
+#pragma once
+#endif
+
+namespace boost {
+namespace atomics {
+namespace detail {
+namespace chrono {
+
+#if defined(__cpp_lib_chrono) && (__cpp_lib_chrono >= 201510l)
+
+using std::chrono::ceil;
+
+#else // defined(__cpp_lib_chrono) && (__cpp_lib_chrono >= 201510l)
+
+template< typename To, typename Rep, typename Period >
+inline constexpr To ceil(std::chrono::duration< Rep, Period > from) noexcept
+{
+    using conv_ratio = std::ratio_divide< Period, typename To::period >;
+    using common_rep = typename std::common_type< Rep, typename To::rep, decltype(conv_ratio::num) >::type;
+    return To(static_cast< typename To::rep >((static_cast< common_rep >(from.count()) * conv_ratio::num) / conv_ratio::den +
+        static_cast< common_rep >(((static_cast< common_rep >(from.count()) * conv_ratio::num) % conv_ratio::den) != static_cast< common_rep >(0))));
+}
+
+#endif // defined(__cpp_lib_chrono) && (__cpp_lib_chrono >= 201510l)
+
+} // namespace chrono
+} // namespace detail
+
+#if defined(CLOCK_REALTIME)
+
+//! Integrate `std::chrono::system_clock` with POSIX clocks
+template< >
+struct posix_clock_traits< std::chrono::system_clock >
+{
+    //! POSIX clock identifier
+    static constexpr clockid_t clock_id = CLOCK_REALTIME;
+
+    //! Function that converts a time point to a timespec structure
+    static timespec to_timespec(std::chrono::system_clock::time_point time_point) noexcept
+    {
+        timespec ts{};
+        std::chrono::nanoseconds::rep time_ns = std::chrono::duration_cast< std::chrono::nanoseconds >(time_point.time_since_epoch()).count();
+        // Note: The standard doesn't require that std::chrono::system_clock epoch matches the POSIX CLOCK_REALTIME epoch. Also, std::chrono::system_clock::to_time_t
+        //       is allowed to round or truncate the time point when converting to time_t resolution, which means to_time_t may return a time before or after time_point.
+        ts.tv_sec = std::chrono::system_clock::to_time_t(std::chrono::system_clock::time_point()) + static_cast< decltype(ts.tv_sec) >(time_ns / 1000000000);
+        time_ns %= 1000000000;
+        if (BOOST_UNLIKELY(time_ns < 0))
+        {
+            --ts.tv_sec;
+            time_ns += 1000000000;
+        }
+        ts.tv_nsec = static_cast< decltype(ts.tv_nsec) >(time_ns);
+        return ts;
+    }
+};
+
+#endif // defined(CLOCK_REALTIME)
+
+} // namespace atomics
+} // namespace boost
+
+#include <boost/atomic/detail/footer.hpp>
+
+#endif // BOOST_ATOMIC_DETAIL_CHRONO_HPP_INCLUDED_