Imported Upstream version 1.67.0upstream/1.67.0

1 files changed, 86 insertions, 0 deletions

diff --git a/boost/atomic/detail/bitwise_fp_cast.hpp b/boost/atomic/detail/bitwise_fp_cast.hpp
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+++ b/boost/atomic/detail/bitwise_fp_cast.hpp
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+/*
+ * 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) 2018 Andrey Semashev
+ */
+/*!
+ * \file   atomic/detail/bitwise_fp_cast.hpp
+ *
+ * This header defines \c bitwise_fp_cast used to convert between storage and floating point value types
+ */
+
+#ifndef BOOST_ATOMIC_DETAIL_BITWISE_FP_CAST_HPP_INCLUDED_
+#define BOOST_ATOMIC_DETAIL_BITWISE_FP_CAST_HPP_INCLUDED_
+
+#include <cstddef>
+#include <boost/atomic/detail/config.hpp>
+#include <boost/atomic/detail/float_sizes.hpp>
+#include <boost/atomic/detail/bitwise_cast.hpp>
+
+#ifdef BOOST_HAS_PRAGMA_ONCE
+#pragma once
+#endif
+
+namespace boost {
+namespace atomics {
+namespace detail {
+
+/*!
+ * \brief The type trait returns the size of the value of the specified floating point type
+ *
+ * This size may be less than <tt>sizeof(T)</tt> if the implementation uses padding bytes for a particular FP type. This is
+ * often the case with 80-bit extended double, which is stored in 12 or 16 bytes with padding filled with garbage.
+ */
+template< typename T >
+struct value_sizeof
+{
+    static BOOST_CONSTEXPR_OR_CONST std::size_t value = sizeof(T);
+};
+
+#if defined(BOOST_ATOMIC_DETAIL_SIZEOF_FLOAT_VALUE)
+template< >
+struct value_sizeof< float >
+{
+    static BOOST_CONSTEXPR_OR_CONST std::size_t value = BOOST_ATOMIC_DETAIL_SIZEOF_FLOAT_VALUE;
+};
+#endif
+
+#if defined(BOOST_ATOMIC_DETAIL_SIZEOF_DOUBLE_VALUE)
+template< >
+struct value_sizeof< double >
+{
+    static BOOST_CONSTEXPR_OR_CONST std::size_t value = BOOST_ATOMIC_DETAIL_SIZEOF_DOUBLE_VALUE;
+};
+#endif
+
+#if defined(BOOST_ATOMIC_DETAIL_SIZEOF_LONG_DOUBLE_VALUE)
+template< >
+struct value_sizeof< long double >
+{
+    static BOOST_CONSTEXPR_OR_CONST std::size_t value = BOOST_ATOMIC_DETAIL_SIZEOF_LONG_DOUBLE_VALUE;
+};
+#endif
+
+template< typename T >
+struct value_sizeof< const T > : value_sizeof< T > {};
+
+template< typename T >
+struct value_sizeof< volatile T > : value_sizeof< T > {};
+
+template< typename T >
+struct value_sizeof< const volatile T > : value_sizeof< T > {};
+
+
+template< typename To, typename From >
+BOOST_FORCEINLINE To bitwise_fp_cast(From const& from) BOOST_NOEXCEPT
+{
+    return atomics::detail::bitwise_cast< To, atomics::detail::value_sizeof< From >::value >(from);
+}
+
+} // namespace detail
+} // namespace atomics
+} // namespace boost
+
+#endif // BOOST_ATOMIC_DETAIL_BITWISE_FP_CAST_HPP_INCLUDED_