luabind/iterator_policy.hpp

   1 // Copyright Daniel Wallin 2007. 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_ITERATOR_POLICY__071111_HPP
   6 # define LUABIND_ITERATOR_POLICY__071111_HPP
   7
   8 # include <luabind/config.hpp>
   9 # include <luabind/detail/policy.hpp>
  10 # include <luabind/detail/convert_to_lua.hpp>
  11
  12 namespace luabind { namespace detail {
  13
  14 template <class Iterator>
  15 struct iterator
  16 {
  17     static int next(lua_State* L)
  18     {
  19         iterator* self = static_cast<iterator*>(
  20             lua_touserdata(L, lua_upvalueindex(1)));
  21
  22         if (self->first != self->last)
  23         {
  24             convert_to_lua(L, *self->first);
  25             ++self->first;
  26         }
  27         else
  28         {
  29             lua_pushnil(L);
  30         }
  31
  32         return 1;
  33     }
  34
  35     static int destroy(lua_State* L)
  36     {
  37         iterator* self = static_cast<iterator*>(
  38             lua_touserdata(L, lua_upvalueindex(1)));
  39         self->~iterator();
  40         return 0;
  41     }
  42
  43     iterator(Iterator first, Iterator last)
  44       : first(first)
  45       , last(last)
  46     {}
  47
  48     Iterator first;
  49     Iterator last;
  50 };
  51
  52 template <class Iterator>
  53 int make_range(lua_State* L, Iterator first, Iterator last)
  54 {
  55     void* storage = lua_newuserdata(L, sizeof(iterator<Iterator>));
  56     lua_newtable(L);
  57     lua_pushcclosure(L, iterator<Iterator>::destroy, 0);
  58     lua_setfield(L, -2, "__gc");
  59     lua_setmetatable(L, -2);
  60     lua_pushcclosure(L, iterator<Iterator>::next, 1);
  61     new (storage) iterator<Iterator>(first, last);
  62     return 1;
  63 }
  64
  65 template <class Container>
  66 int make_range(lua_State* L, Container& container)
  67 {
  68     return make_range(L, container.begin(), container.end());
  69 }
  70
  71 struct iterator_converter
  72 {
  73     typedef boost::mpl::bool_<false> is_value_converter;
  74     typedef iterator_converter type;
  75
  76     template <class Container>
  77     void apply(lua_State* L, Container& container)
  78     {
  79         make_range(L, container);
  80     }
  81
  82     template <class Container>
  83     void apply(lua_State* L, Container const& container)
  84     {
  85         make_range(L, container);
  86     }
  87 };
  88
  89 struct iterator_policy : conversion_policy<0>
  90 {
  91     static void precall(lua_State*, index_map const&)
  92     {}
  93
  94     static void postcall(lua_State*, index_map const&)
  95     {}
  96
  97     template <class T, class Direction>
  98     struct apply
  99     {
 100         typedef iterator_converter type;
 101     };
 102 };
 103
 104 }} // namespace luabind::detail
 105
 106 namespace luabind { namespace {
 107
 108 LUABIND_ANONYMOUS_FIX detail::policy_cons<
 109     detail::iterator_policy, detail::null_type> return_stl_iterator;
 110
 111 }} // namespace luabind::unnamed
 112
 113 #endif // LUABIND_ITERATOR_POLICY__071111_HPP
 114