python/include/boost/python/object/iterator.hpp at develop · elmopl/python · GitHub

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// 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/detail/type_traits.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/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

};

typedef next next_fn;

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 boost::python::detail::add_const<iterator>::type iterator_const;

typedef typename boost::python::detail::add_lvalue_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

python/include/boost/python/object/iterator.hpp at develop · elmopl/python · GitHub

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