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