Chris@16: // Copyright David Abrahams 2002.
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See
Chris@16: // accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: #ifndef ITERATOR_DWA2002510_HPP
Chris@16: # define ITERATOR_DWA2002510_HPP
Chris@16: 
Chris@16: # include <boost/python/detail/prefix.hpp>
Chris@16: 
Chris@16: # include <boost/python/class.hpp>
Chris@16: # include <boost/python/return_value_policy.hpp>
Chris@16: # include <boost/python/return_by_value.hpp>
Chris@16: # include <boost/python/handle.hpp>
Chris@16: # include <boost/python/make_function.hpp>
Chris@16: 
Chris@16: # include <boost/python/object/iterator_core.hpp>
Chris@16: # include <boost/python/object/class_detail.hpp>
Chris@16: # include <boost/python/object/function_object.hpp>
Chris@16: 
Chris@16: # include <boost/mpl/vector/vector10.hpp>
Chris@16: # include <boost/mpl/if.hpp>
Chris@16: 
Chris@16: # include <boost/python/detail/raw_pyobject.hpp>
Chris@16: 
Chris@16: # include <boost/type.hpp>
Chris@16: 
Chris@16: # include <boost/type_traits/is_same.hpp>
Chris@16: # include <boost/type_traits/add_reference.hpp>
Chris@16: # include <boost/type_traits/add_const.hpp>
Chris@16: 
Chris@16: # include <boost/detail/iterator.hpp>
Chris@16: 
Chris@16: namespace boost { namespace python { namespace objects {
Chris@16: 
Chris@16: // CallPolicies for the next() method of iterators. We don't want
Chris@16: // users to have to explicitly specify that the references returned by
Chris@16: // iterators are copied, so we just replace the result_converter from
Chris@16: // the default_iterator_call_policies with a permissive one which
Chris@16: // always copies the result.
Chris@16: typedef return_value_policy<return_by_value> default_iterator_call_policies;
Chris@16: 
Chris@16: // Instantiations of these are wrapped to produce Python iterators.
Chris@16: template <class NextPolicies, class Iterator>
Chris@16: struct iterator_range
Chris@16: {
Chris@16:     iterator_range(object sequence, Iterator start, Iterator finish);
Chris@16: 
Chris@16:     typedef boost::detail::iterator_traits<Iterator> traits_t;
Chris@16: 
Chris@16:     struct next
Chris@16:     {
Chris@16:         typedef typename mpl::if_<
Chris@16:             is_reference<
Chris@16:                 typename traits_t::reference
Chris@16:             >
Chris@16:           , typename traits_t::reference
Chris@16:           , typename traits_t::value_type
Chris@16:         >::type result_type;
Chris@16:         
Chris@16:         result_type
Chris@16:         operator()(iterator_range<NextPolicies,Iterator>& self)
Chris@16:         {
Chris@16:             if (self.m_start == self.m_finish)
Chris@16:                 stop_iteration_error();
Chris@16:             return *self.m_start++;
Chris@16:         }
Chris@16: 
Chris@16: # if BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003))
Chris@16:         // CWPro8 has a codegen problem when this is an empty class
Chris@16:         int garbage;
Chris@16: # endif 
Chris@16:     };
Chris@16:     
Chris@16: # ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
Chris@16:     // for compilers which can't deduce the value_type of pointers, we
Chris@16:     // have a special implementation of next.  This takes advantage of
Chris@16:     // the fact that T* results are treated like T& results by
Chris@16:     // Boost.Python's function wrappers.
Chris@16:     struct next_ptr
Chris@16:     {
Chris@16:         typedef Iterator result_type;
Chris@16:         
Chris@16:         result_type
Chris@16:         operator()(iterator_range<NextPolicies,Iterator>& self)
Chris@16:         {
Chris@16:             if (self.m_start == self.m_finish)
Chris@16:                 stop_iteration_error();
Chris@16:             return self.m_start++;
Chris@16:         }
Chris@16:     };
Chris@16:     
Chris@16:     typedef mpl::if_<
Chris@16:         is_same<
Chris@16:             boost::detail::please_invoke_BOOST_TT_BROKEN_COMPILER_SPEC_on_cv_unqualified_pointee<Iterator>
Chris@16:           , typename traits_t::value_type
Chris@16:         >
Chris@16:       , next_ptr
Chris@16:       , next
Chris@16:     >::type next_fn;
Chris@16: # else
Chris@16:     typedef next next_fn;
Chris@16: # endif
Chris@16:     
Chris@16:     object m_sequence; // Keeps the sequence alive while iterating.
Chris@16:     Iterator m_start;
Chris@16:     Iterator m_finish;
Chris@16: };
Chris@16: 
Chris@16: namespace detail
Chris@16: {
Chris@16:   // Get a Python class which contains the given iterator and
Chris@16:   // policies, creating it if necessary. Requires: NextPolicies is
Chris@16:   // default-constructible.
Chris@16:   template <class Iterator, class NextPolicies>
Chris@16:   object demand_iterator_class(char const* name, Iterator* = 0, NextPolicies const& policies = NextPolicies())
Chris@16:   {
Chris@16:       typedef iterator_range<NextPolicies,Iterator> range_;
Chris@16: 
Chris@16:       // Check the registry. If one is already registered, return it.
Chris@16:       handle<> class_obj(
Chris@16:           objects::registered_class_object(python::type_id<range_>()));
Chris@16:         
Chris@16:       if (class_obj.get() != 0)
Chris@16:           return object(class_obj);
Chris@16: 
Chris@16:       typedef typename range_::next_fn next_fn;
Chris@16:       typedef typename next_fn::result_type result_type;
Chris@16:       
Chris@16:       return class_<range_>(name, no_init)
Chris@16:           .def("__iter__", identity_function())
Chris@16:           .def(
Chris@16: #if PY_VERSION_HEX >= 0x03000000
Chris@16:               "__next__"
Chris@16: #else
Chris@16:               "next"
Chris@16: #endif
Chris@16:             , make_function(
Chris@16:                 next_fn()
Chris@16:               , policies
Chris@16:               , mpl::vector2<result_type,range_&>()
Chris@16:             ));
Chris@16:   }
Chris@16: 
Chris@16:   // A function object which builds an iterator_range.
Chris@16:   template <
Chris@16:       class Target
Chris@16:     , class Iterator
Chris@16:     , class Accessor1
Chris@16:     , class Accessor2
Chris@16:     , class NextPolicies
Chris@16:   >
Chris@16:   struct py_iter_
Chris@16:   {
Chris@16:       py_iter_(Accessor1 const& get_start, Accessor2 const& get_finish)
Chris@16:         : m_get_start(get_start)
Chris@16:         , m_get_finish(get_finish)
Chris@16:       {}
Chris@16:       
Chris@16:       // Extract an object x of the Target type from the first Python
Chris@16:       // argument, and invoke get_start(x)/get_finish(x) to produce
Chris@16:       // iterators, which are used to construct a new iterator_range<>
Chris@16:       // object that gets wrapped into a Python iterator.
Chris@16:       iterator_range<NextPolicies,Iterator>
Chris@16:       operator()(back_reference<Target&> x) const
Chris@16:       {
Chris@16:           // Make sure the Python class is instantiated.
Chris@16:           detail::demand_iterator_class("iterator", (Iterator*)0, NextPolicies());
Chris@16:           
Chris@16:           return iterator_range<NextPolicies,Iterator>(
Chris@16:               x.source()
Chris@16:             , m_get_start(x.get())
Chris@16:             , m_get_finish(x.get())
Chris@16:           );
Chris@16:       }
Chris@16:    private:
Chris@16:       Accessor1 m_get_start;
Chris@16:       Accessor2 m_get_finish;
Chris@16:   };
Chris@16: 
Chris@16:   template <class Target, class Iterator, class NextPolicies, class Accessor1, class Accessor2>
Chris@16:   inline object make_iterator_function(
Chris@16:       Accessor1 const& get_start
Chris@16:     , Accessor2 const& get_finish
Chris@16:     , NextPolicies const& /*next_policies*/
Chris@16:     , Iterator const& (*)()
Chris@16:     , boost::type<Target>*
Chris@16:     , int
Chris@16:   )
Chris@16:   {
Chris@16:       return make_function(
Chris@16:           py_iter_<Target,Iterator,Accessor1,Accessor2,NextPolicies>(get_start, get_finish)
Chris@16:         , default_call_policies()
Chris@16:         , mpl::vector2<iterator_range<NextPolicies,Iterator>, back_reference<Target&> >()
Chris@16:       );
Chris@16:   }
Chris@16: 
Chris@16:   template <class Target, class Iterator, class NextPolicies, class Accessor1, class Accessor2>
Chris@16:   inline object make_iterator_function(
Chris@16:       Accessor1 const& get_start
Chris@16:     , Accessor2 const& get_finish
Chris@16:     , NextPolicies const& next_policies
Chris@16:     , Iterator& (*)()
Chris@16:     , boost::type<Target>*
Chris@16:     , ...)
Chris@16:   {
Chris@16:       return make_iterator_function(
Chris@16:           get_start
Chris@16:         , get_finish
Chris@16:         , next_policies
Chris@16:         , (Iterator const&(*)())0
Chris@16:         , (boost::type<Target>*)0
Chris@16:         , 0
Chris@16:       );
Chris@16:   }
Chris@16: 
Chris@16: }
Chris@16: 
Chris@16: // Create a Python callable object which accepts a single argument
Chris@16: // convertible to the C++ Target type and returns a Python
Chris@16: // iterator. The Python iterator uses get_start(x) and get_finish(x)
Chris@16: // (where x is an instance of Target) to produce begin and end
Chris@16: // iterators for the range, and an instance of NextPolicies is used as
Chris@16: // CallPolicies for the Python iterator's next() function. 
Chris@16: template <class Target, class NextPolicies, class Accessor1, class Accessor2>
Chris@16: inline object make_iterator_function(
Chris@16:     Accessor1 const& get_start
Chris@16:   , Accessor2 const& get_finish
Chris@16:   , NextPolicies const& next_policies
Chris@16:   , boost::type<Target>* = 0
Chris@16: )
Chris@16: {
Chris@16:     typedef typename Accessor1::result_type iterator;
Chris@16:     typedef typename add_const<iterator>::type iterator_const;
Chris@16:     typedef typename add_reference<iterator_const>::type iterator_cref;
Chris@16:       
Chris@16:     return detail::make_iterator_function(
Chris@16:         get_start
Chris@16:       , get_finish
Chris@16:       , next_policies
Chris@16:       , (iterator_cref(*)())0
Chris@16:       , (boost::type<Target>*)0
Chris@16:       , 0
Chris@16:     );
Chris@16: }
Chris@16: 
Chris@16: //
Chris@16: // implementation
Chris@16: //
Chris@16: template <class NextPolicies, class Iterator>
Chris@16: inline iterator_range<NextPolicies,Iterator>::iterator_range(
Chris@16:     object sequence, Iterator start, Iterator finish)
Chris@16:     : m_sequence(sequence), m_start(start), m_finish(finish)
Chris@16: {
Chris@16: }
Chris@16: 
Chris@16: }}} // namespace boost::python::objects
Chris@16: 
Chris@16: #endif // ITERATOR_DWA2002510_HPP