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*>(lua_touserdata(L, 1));
  38         self->~iterator();
  39         return 0;
  40     }
  41
  42     iterator(Iterator first, Iterator last)
  43       : first(first)
  44       , last(last)
  45     {}
  46
  47     Iterator first;
  48     Iterator last;
  49 };
  50
  51 template <class Iterator>
  52 int make_range(lua_State* L, Iterator first, Iterator last)
  53 {
  54     void* storage = lua_newuserdata(L, sizeof(iterator<Iterator>));
  55     lua_newtable(L);
  56     lua_pushcclosure(L, iterator<Iterator>::destroy, 0);
  57     lua_setfield(L, -2, "__gc");
  58     lua_setmetatable(L, -2);
  59     lua_pushcclosure(L, iterator<Iterator>::next, 1);
  60     new (storage) iterator<Iterator>(first, last);
  61     return 1;
  62 }
  63
  64 template <class Container>
  65 int make_range(lua_State* L, Container& container)
  66 {
  67     return make_range(L, container.begin(), container.end());
  68 }
  69
  70 struct iterator_converter
  71 {
  72     typedef iterator_converter type;
  73
  74     template <class Container>
  75     void apply(lua_State* L, Container& container)
  76     {
  77         make_range(L, container);
  78     }
  79
  80     template <class Container>
  81     void apply(lua_State* L, Container const& container)
  82     {
  83         make_range(L, container);
  84     }
  85 };
  86
  87 struct iterator_policy : conversion_policy<0>
  88 {
  89     static void precall(lua_State*, index_map const&)
  90     {}
  91
  92     static void postcall(lua_State*, index_map const&)
  93     {}
  94
  95     template <class T, class Direction>
  96     struct apply
  97     {
  98         typedef iterator_converter type;
  99     };
 100 };
 101
 102 }} // namespace luabind::detail
 103
 104 namespace luabind { namespace {
 105
 106 LUABIND_ANONYMOUS_FIX detail::policy_cons<
 107     detail::iterator_policy, detail::null_type> return_stl_iterator;
 108
 109 }} // namespace luabind::unnamed
 110
 111 #endif // LUABIND_ITERATOR_POLICY__071111_HPP
 112