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 iterator_converter type;
  74
  75     template <class Container>
  76     void apply(lua_State* L, Container& container)
  77     {
  78         make_range(L, container);
  79     }
  80
  81     template <class Container>
  82     void apply(lua_State* L, Container const& container)
  83     {
  84         make_range(L, container);
  85     }
  86 };
  87
  88 struct iterator_policy : conversion_policy<0>
  89 {
  90     static void precall(lua_State*, index_map const&)
  91     {}
  92
  93     static void postcall(lua_State*, index_map const&)
  94     {}
  95
  96     template <class T, class Direction>
  97     struct apply
  98     {
  99         typedef iterator_converter type;
 100     };
 101 };
 102
 103 }} // namespace luabind::detail
 104
 105 namespace luabind { namespace {
 106
 107 LUABIND_ANONYMOUS_FIX detail::policy_cons<
 108     detail::iterator_policy, detail::null_type> return_stl_iterator;
 109
 110 }} // namespace luabind::unnamed
 111
 112 #endif // LUABIND_ITERATOR_POLICY__071111_HPP
 113