76 lines
2.5 KiB
Plaintext
76 lines
2.5 KiB
Plaintext
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// Copyright (C) 2003, 2008 Fernando Luis Cacciola Carballal.
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// Copyright (C) 2016 Andrzej Krzemienski.
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//
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// Use, modification, and distribution is subject to the Boost Software
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// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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//
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// See http://www.boost.org/libs/optional for documentation.
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//
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// You are welcome to contact the author at:
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// fernando_cacciola@hotmail.com
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// akrzemi1@gmail.com
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#ifndef BOOST_OPTIONAL_OPTIONAL_DETAIL_OPTIONAL_ALIGNED_STORAGE_AJK_12FEB2016_HPP
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#define BOOST_OPTIONAL_OPTIONAL_DETAIL_OPTIONAL_ALIGNED_STORAGE_AJK_12FEB2016_HPP
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namespace boost {
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namespace optional_detail {
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// This local class is used instead of that in "aligned_storage.hpp"
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// because I've found the 'official' class to ICE BCB5.5
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// when some types are used with optional<>
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// (due to sizeof() passed down as a non-type template parameter)
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template <class T>
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class aligned_storage
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{
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// Borland ICEs if unnamed unions are used for this!
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union
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// This works around GCC warnings about breaking strict aliasing rules when casting storage address to T*
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#if defined(BOOST_OPTIONAL_DETAIL_USE_ATTRIBUTE_MAY_ALIAS)
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__attribute__((__may_alias__))
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#endif
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dummy_u
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{
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char data[ sizeof(T) ];
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BOOST_DEDUCED_TYPENAME type_with_alignment<
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::boost::alignment_of<T>::value >::type aligner_;
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} dummy_ ;
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public:
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#if defined(BOOST_OPTIONAL_DETAIL_USE_ATTRIBUTE_MAY_ALIAS)
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void const* address() const { return &dummy_; }
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void * address() { return &dummy_; }
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#else
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void const* address() const { return dummy_.data; }
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void * address() { return dummy_.data; }
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#endif
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#if defined(BOOST_OPTIONAL_DETAIL_USE_ATTRIBUTE_MAY_ALIAS)
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// This workaround is supposed to silence GCC warnings about broken strict aliasing rules
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T const* ptr_ref() const
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{
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union { void const* ap_pvoid; T const* as_ptype; } caster = { address() };
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return caster.as_ptype;
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}
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T * ptr_ref()
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{
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union { void* ap_pvoid; T* as_ptype; } caster = { address() };
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return caster.as_ptype;
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}
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#else
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T const* ptr_ref() const { return static_cast<T const*>(address()); }
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T * ptr_ref() { return static_cast<T *> (address()); }
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#endif
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T const& ref() const { return *ptr_ref(); }
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T & ref() { return *ptr_ref(); }
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} ;
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} // namespace optional_detail
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} // namespace boost
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#endif // header guard
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