luabind/detail/inheritance.hpp

   1 // Copyright Daniel Wallin 2009. Use, modification and distribution is
   2 // subject to the Boost Software License, Version 1.0. (See accompanying
   3 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   4
   5 #ifndef LUABIND_INHERITANCE_090217_HPP
   6 # define LUABIND_INHERITANCE_090217_HPP
   7
   8 # include <cassert>
   9 # include <limits>
  10 # include <map>
  11 # include <memory>
  12 # include <vector>
  13 # include <luabind/typeid.hpp>
  14
  15 namespace luabind { namespace detail {
  16
  17 typedef void*(*cast_function)(void*);
  18 typedef std::size_t class_id;
  19
  20 class_id const unknown_class = std::numeric_limits<class_id>::max();
  21
  22 class class_rep;
  23
  24 class LUABIND_API cast_graph
  25 {
  26 public:
  27     cast_graph();
  28     ~cast_graph();
  29
  30     // `src` and `p` here describe the *most derived* object. This means that
  31     // for a polymorphic type, the pointer must be cast with
  32     // dynamic_cast<void*> before being passed in here, and `src` has to
  33     // match typeid(*p).
  34     std::pair<void*, std::size_t> cast(
  35         void* p, class_id src, class_id target
  36       , class_id dynamic_id, void const* dynamic_ptr) const;
  37     void insert(class_id src, class_id target, cast_function cast);
  38
  39 private:
  40     class impl;
  41     std::auto_ptr<impl> m_impl;
  42 };
  43
  44 // Maps a type_id to a class_id. Note that this..
  45 class class_id_map
  46 {
  47 public:
  48     class_id get(type_id const& type) const;
  49     class_id get_local(type_id const& type);
  50     void put(class_id id, type_id const& type);
  51
  52 private:
  53     typedef std::map<type_id, class_id> map_type;
  54     map_type m_classes;
  55 };
  56
  57 inline class_id class_id_map::get(type_id const& type) const
  58 {
  59     map_type::const_iterator i = m_classes.find(type);
  60     if (i == m_classes.end() || i->second > unknown_class / 2)
  61         return unknown_class;
  62     return i->second;
  63 }
  64
  65 inline class_id class_id_map::get_local(type_id const& type)
  66 {
  67     std::pair<map_type::iterator, bool> result = m_classes.insert(
  68         std::make_pair(type, 0));
  69
  70     if (result.second)
  71         result.first->second = unknown_class - m_classes.size();
  72
  73     return result.first->second;
  74 }
  75
  76 inline void class_id_map::put(class_id id, type_id const& type)
  77 {
  78     std::pair<map_type::iterator, bool> result = m_classes.insert(
  79         std::make_pair(type, id));
  80     assert(result.second || result.first->second == id);
  81     (void)result;
  82 }
  83
  84 class class_map
  85 {
  86 public:
  87     class_rep* get(class_id id) const;
  88     void put(class_id id, class_rep* cls);
  89
  90 private:
  91     std::vector<class_rep*> m_classes;
  92 };
  93
  94 inline class_rep* class_map::get(class_id id) const
  95 {
  96     if (id >= m_classes.size())
  97         return 0;
  98     return m_classes[id];
  99 }
 100
 101 inline void class_map::put(class_id id, class_rep* cls)
 102 {
 103     if (id >= m_classes.size())
 104         m_classes.resize(id + 1);
 105     m_classes[id] = cls;
 106 }
 107
 108 template <class S, class T>
 109 struct static_cast_
 110 {
 111     static void* execute(void* p)
 112     {
 113         return static_cast<T*>(static_cast<S*>(p));
 114     }
 115 };
 116
 117 template <class S, class T>
 118 struct dynamic_cast_
 119 {
 120     static void* execute(void* p)
 121     {
 122         return dynamic_cast<T*>(static_cast<S*>(p));
 123     }
 124 };
 125
 126 // Thread safe class_id allocation.
 127 LUABIND_API class_id allocate_class_id();
 128
 129 template <class T>
 130 struct registered_class
 131 {
 132     static class_id const id;
 133 };
 134
 135 template <class T>
 136 class_id const registered_class<T>::id = allocate_class_id();
 137
 138 template <class T>
 139 struct registered_class<T const>
 140   : registered_class<T>
 141 {};
 142
 143 }} // namespace luabind::detail
 144
 145 #endif // LUABIND_INHERITANCE_090217_HPP