Line data    Source code

       1             : // Copyright (C) 2003, 2008 Fernando Luis Cacciola Carballal.
       2             : // Copyright (C) 2016 Andrzej Krzemienski.
       3             : //
       4             : // Use, modification, and distribution is subject to the Boost Software
       5             : // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
       6             : // http://www.boost.org/LICENSE_1_0.txt)
       7             : //
       8             : // See http://www.boost.org/libs/optional for documentation.
       9             : //
      10             : // You are welcome to contact the author at:
      11             : //  fernando_cacciola@hotmail.com
      12             : //  akrzemi1@gmail.com
      13             : 
      14             : #ifndef BOOST_OPTIONAL_OPTIONAL_DETAIL_OPTIONAL_ALIGNED_STORAGE_AJK_12FEB2016_HPP
      15             : #define BOOST_OPTIONAL_OPTIONAL_DETAIL_OPTIONAL_ALIGNED_STORAGE_AJK_12FEB2016_HPP
      16             : 
      17             : namespace boost {
      18             : 
      19             : namespace optional_detail {
      20             : // This local class is used instead of that in "aligned_storage.hpp"
      21             : // because I've found the 'official' class to ICE BCB5.5
      22             : // when some types are used with optional<>
      23             : // (due to sizeof() passed down as a non-type template parameter)
      24             : template <class T>
      25             : class aligned_storage
      26             : {
      27             :     // Borland ICEs if unnamed unions are used for this!
      28             :     // BOOST_MAY_ALIAS works around GCC warnings about breaking strict aliasing rules when casting storage address to T*
      29             :     union BOOST_MAY_ALIAS dummy_u
      30             :     {
      31             :         char data[ sizeof(T) ];
      32             :         BOOST_DEDUCED_TYPENAME type_with_alignment<
      33             :           ::boost::alignment_of<T>::value >::type aligner_;
      34             :     } dummy_ ;
      35             : 
      36             :   public:
      37             : 
      38             : #if defined(BOOST_OPTIONAL_DETAIL_USE_ATTRIBUTE_MAY_ALIAS)
      39           0 :     void const* address() const { return &dummy_; }
      40           0 :     void      * address()       { return &dummy_; }
      41             : #else
      42             :     void const* address() const { return dummy_.data; }
      43             :     void      * address()       { return dummy_.data; }
      44             : #endif
      45             : 
      46             : #if defined(BOOST_OPTIONAL_DETAIL_USE_ATTRIBUTE_MAY_ALIAS)
      47             :     // This workaround is supposed to silence GCC warnings about broken strict aliasing rules
      48           0 :     T const* ptr_ref() const
      49             :     {
      50           0 :         union { void const* ap_pvoid; T const* as_ptype; } caster = { address() };
      51             :         return caster.as_ptype;
      52             :     }
      53           0 :     T *      ptr_ref()
      54             :     {
      55           0 :         union { void* ap_pvoid; T* as_ptype; } caster = { address() };
      56             :         return caster.as_ptype;
      57             :     }
      58             : #else
      59             :     T const* ptr_ref() const { return static_cast<T const*>(address()); }
      60             :     T *      ptr_ref()       { return static_cast<T *>     (address()); }
      61             : #endif
      62             : 
      63           0 :     T const& ref() const { return *ptr_ref(); }
      64           0 :     T &      ref()       { return *ptr_ref(); }
      65             :   
      66             : } ;
      67             : 
      68             : } // namespace optional_detail
      69             : } // namespace boost
      70             : 
      71             : #endif // header guard