ceph/src/boost/libs/serialization/include/boost/serialization/void_cast.hpp

   1 #ifndef  BOOST_SERIALIZATION_VOID_CAST_HPP
   2 #define BOOST_SERIALIZATION_VOID_CAST_HPP
   3
   4 // MS compatible compilers support #pragma once
   5 #if defined(_MSC_VER)
   6 # pragma once
   7 #endif
   8
   9 /////////1/////////2/////////3/////////4/////////5/////////6/////////7/////////8
  10 // void_cast.hpp:   interface for run-time casting of void pointers.
  11
  12 // (C) Copyright 2002-2009 Robert Ramey - http://www.rrsd.com .
  13 // Use, modification and distribution is subject to the Boost Software
  14 // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
  15 // http://www.boost.org/LICENSE_1_0.txt)
  16 // gennadiy.rozental@tfn.com
  17
  18 //  See http://www.boost.org for updates, documentation, and revision history.
  19
  20 #include <cstddef> // for ptrdiff_t
  21 #include <boost/config.hpp>
  22 #include <boost/noncopyable.hpp>
  23
  24 #include <boost/serialization/smart_cast.hpp>
  25 #include <boost/serialization/singleton.hpp>
  26 #include <boost/serialization/force_include.hpp>
  27 #include <boost/serialization/type_info_implementation.hpp>
  28 #include <boost/serialization/extended_type_info.hpp>
  29 #include <boost/type_traits/is_virtual_base_of.hpp>
  30 #include <boost/serialization/void_cast_fwd.hpp>
  31
  32 #include <boost/serialization/config.hpp>
  33 #include <boost/config/abi_prefix.hpp> // must be the last header
  34
  35 #ifdef BOOST_MSVC
  36 #  pragma warning(push)
  37 #  pragma warning(disable : 4251 4231 4660 4275)
  38 #endif
  39
  40 namespace boost {
  41 namespace serialization {
  42
  43 class extended_type_info;
  44
  45 // Given a void *, assume that it really points to an instance of one type
  46 // and alter it so that it would point to an instance of a related type.
  47 // Return the altered pointer. If there exists no sequence of casts that
  48 // can transform from_type to to_type, return a NULL.
  49
  50 BOOST_SERIALIZATION_DECL void const *
  51 void_upcast(
  52     extended_type_info const & derived,
  53     extended_type_info const & base,
  54     void const * const t
  55 );
  56
  57 inline void *
  58 void_upcast(
  59     extended_type_info const & derived,
  60     extended_type_info const & base,
  61     void * const t
  62 ){
  63     return const_cast<void*>(void_upcast(
  64         derived,
  65         base,
  66         const_cast<void const *>(t)
  67     ));
  68 }
  69
  70 BOOST_SERIALIZATION_DECL void const *
  71 void_downcast(
  72     extended_type_info const & derived,
  73     extended_type_info const & base,
  74     void const * const t
  75 );
  76
  77 inline void *
  78 void_downcast(
  79     extended_type_info const & derived,
  80     extended_type_info const & base,
  81     void * const t
  82 ){
  83     return const_cast<void*>(void_downcast(
  84         derived,
  85         base,
  86         const_cast<void const *>(t)
  87     ));
  88 }
  89
  90 namespace void_cast_detail {
  91
  92 class BOOST_SYMBOL_VISIBLE void_caster :
  93     private boost::noncopyable
  94 {
  95     friend
  96     BOOST_SERIALIZATION_DECL void const *
  97     boost::serialization::void_upcast(
  98         extended_type_info const & derived,
  99         extended_type_info const & base,
 100         void const * const
 101     );
 102     friend
 103     BOOST_SERIALIZATION_DECL void const *
 104     boost::serialization::void_downcast(
 105         extended_type_info const & derived,
 106         extended_type_info const & base,
 107         void const * const
 108     );
 109 protected:
 110     BOOST_SERIALIZATION_DECL void recursive_register(bool includes_virtual_base = false) const;
 111     BOOST_SERIALIZATION_DECL void recursive_unregister() const;
 112     virtual bool has_virtual_base() const = 0;
 113 public:
 114     // Data members
 115     const extended_type_info * m_derived;
 116     const extended_type_info * m_base;
 117     /*const*/ std::ptrdiff_t m_difference;
 118     void_caster const * const m_parent;
 119
 120     // note that void_casters are keyed on value of
 121     // member extended type info records - NOT their
 122     // addresses.  This is necessary in order for the
 123     // void cast operations to work across dll and exe
 124     // module boundries.
 125     bool operator<(const void_caster & rhs) const;
 126
 127     const void_caster & operator*(){
 128         return *this;
 129     }
 130     // each derived class must re-implement these;
 131     virtual void const * upcast(void const * const t) const = 0;
 132     virtual void const * downcast(void const * const t) const = 0;
 133     // Constructor
 134     void_caster(
 135         extended_type_info const * derived,
 136         extended_type_info const * base,
 137         std::ptrdiff_t difference = 0,
 138         void_caster const * const parent = 0
 139     ) :
 140         m_derived(derived),
 141         m_base(base),
 142         m_difference(difference),
 143         m_parent(parent)
 144     {}
 145     virtual ~void_caster(){}
 146 };
 147
 148 #ifdef BOOST_MSVC
 149 #  pragma warning(push)
 150 #  pragma warning(disable : 4251 4231 4660 4275 4511 4512)
 151 #endif
 152
 153 template <class Derived, class Base>
 154 class BOOST_SYMBOL_VISIBLE void_caster_primitive :
 155     public void_caster
 156 {
 157     virtual void const * downcast(void const * const t) const {
 158         const Derived * d =
 159             boost::serialization::smart_cast<const Derived *, const Base *>(
 160                 static_cast<const Base *>(t)
 161             );
 162         return d;
 163     }
 164     virtual void const * upcast(void const * const t) const {
 165         const Base * b =
 166             boost::serialization::smart_cast<const Base *, const Derived *>(
 167                 static_cast<const Derived *>(t)
 168             );
 169         return b;
 170     }
 171     virtual bool has_virtual_base() const {
 172         return false;
 173     }
 174 public:
 175     void_caster_primitive();
 176     virtual ~void_caster_primitive();
 177 };
 178
 179 template <class Derived, class Base>
 180 void_caster_primitive<Derived, Base>::void_caster_primitive() :
 181     void_caster(
 182         & type_info_implementation<Derived>::type::get_const_instance(),
 183         & type_info_implementation<Base>::type::get_const_instance(),
 184         // note:I wanted to displace from 0 here, but at least one compiler
 185         // treated 0 by not shifting it at all.
 186         reinterpret_cast<std::ptrdiff_t>(
 187             static_cast<Derived *>(
 188                 reinterpret_cast<Base *>(8)
 189             )
 190         ) - 8
 191     )
 192 {
 193     recursive_register();
 194 }
 195
 196 template <class Derived, class Base>
 197 void_caster_primitive<Derived, Base>::~void_caster_primitive(){
 198     recursive_unregister();
 199 }
 200
 201 template <class Derived, class Base>
 202 class BOOST_SYMBOL_VISIBLE void_caster_virtual_base :
 203     public void_caster
 204 {
 205     virtual bool has_virtual_base() const {
 206         return true;
 207     }
 208 public:
 209     virtual void const * downcast(void const * const t) const {
 210         const Derived * d =
 211             dynamic_cast<const Derived *>(
 212                 static_cast<const Base *>(t)
 213             );
 214         return d;
 215     }
 216     virtual void const * upcast(void const * const t) const {
 217         const Base * b =
 218             dynamic_cast<const Base *>(
 219                 static_cast<const Derived *>(t)
 220             );
 221         return b;
 222     }
 223     void_caster_virtual_base();
 224     virtual ~void_caster_virtual_base();
 225 };
 226
 227 #ifdef BOOST_MSVC
 228 #pragma warning(pop)
 229 #endif
 230
 231 template <class Derived, class Base>
 232 void_caster_virtual_base<Derived,Base>::void_caster_virtual_base() :
 233     void_caster(
 234         & (type_info_implementation<Derived>::type::get_const_instance()),
 235         & (type_info_implementation<Base>::type::get_const_instance())
 236     )
 237 {
 238     recursive_register(true);
 239 }
 240
 241 template <class Derived, class Base>
 242 void_caster_virtual_base<Derived,Base>::~void_caster_virtual_base(){
 243     recursive_unregister();
 244 }
 245
 246 template <class Derived, class Base>
 247 struct BOOST_SYMBOL_VISIBLE void_caster_base :
 248     public void_caster
 249 {
 250     typedef
 251         typename mpl::eval_if<boost::is_virtual_base_of<Base,Derived>,
 252             mpl::identity<
 253                 void_cast_detail::void_caster_virtual_base<Derived, Base>
 254             >
 255         ,// else
 256             mpl::identity<
 257                 void_cast_detail::void_caster_primitive<Derived, Base>
 258             >
 259         >::type type;
 260 };
 261
 262 } // void_cast_detail
 263
 264 template<class Derived, class Base>
 265 BOOST_DLLEXPORT
 266 inline const void_cast_detail::void_caster & void_cast_register(
 267     Derived const * /* dnull = NULL */,
 268     Base const * /* bnull = NULL */
 269 ){
 270     typedef
 271         typename mpl::eval_if<boost::is_virtual_base_of<Base,Derived>,
 272             mpl::identity<
 273                 void_cast_detail::void_caster_virtual_base<Derived, Base>
 274             >
 275         ,// else
 276             mpl::identity<
 277                 void_cast_detail::void_caster_primitive<Derived, Base>
 278             >
 279         >::type typex;
 280     return singleton<typex>::get_const_instance();
 281 }
 282
 283 template<class Derived, class Base>
 284 class BOOST_SYMBOL_VISIBLE void_caster :
 285     public void_cast_detail::void_caster_base<Derived, Base>::type
 286 {
 287 };
 288
 289 } // namespace serialization
 290 } // namespace boost
 291
 292 #ifdef BOOST_MSVC
 293 #  pragma warning(pop)
 294 #endif
 295
 296 #include <boost/config/abi_suffix.hpp> // pops abi_suffix.hpp pragmas
 297
 298 #endif // BOOST_SERIALIZATION_VOID_CAST_HPP