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1 | // Copyright David Abrahams 2002. |
2 | // Distributed under the Boost Software License, Version 1.0. (See | |
3 | // accompanying file LICENSE_1_0.txt or copy at | |
4 | // http://www.boost.org/LICENSE_1_0.txt) | |
5 | #ifndef ITERATOR_DWA2002510_HPP | |
6 | # define ITERATOR_DWA2002510_HPP | |
7 | ||
8 | # include <boost/python/detail/prefix.hpp> | |
b32b8144 | 9 | # include <boost/python/detail/type_traits.hpp> |
7c673cae FG |
10 | |
11 | # include <boost/python/class.hpp> | |
12 | # include <boost/python/return_value_policy.hpp> | |
13 | # include <boost/python/return_by_value.hpp> | |
14 | # include <boost/python/handle.hpp> | |
15 | # include <boost/python/make_function.hpp> | |
16 | ||
17 | # include <boost/python/object/iterator_core.hpp> | |
18 | # include <boost/python/object/class_detail.hpp> | |
19 | # include <boost/python/object/function_object.hpp> | |
20 | ||
21 | # include <boost/mpl/vector/vector10.hpp> | |
22 | # include <boost/mpl/if.hpp> | |
23 | ||
24 | # include <boost/python/detail/raw_pyobject.hpp> | |
25 | ||
26 | # include <boost/type.hpp> | |
27 | ||
7c673cae FG |
28 | # include <boost/detail/iterator.hpp> |
29 | ||
30 | namespace boost { namespace python { namespace objects { | |
31 | ||
32 | // CallPolicies for the next() method of iterators. We don't want | |
33 | // users to have to explicitly specify that the references returned by | |
34 | // iterators are copied, so we just replace the result_converter from | |
35 | // the default_iterator_call_policies with a permissive one which | |
36 | // always copies the result. | |
37 | typedef return_value_policy<return_by_value> default_iterator_call_policies; | |
38 | ||
39 | // Instantiations of these are wrapped to produce Python iterators. | |
40 | template <class NextPolicies, class Iterator> | |
41 | struct iterator_range | |
42 | { | |
43 | iterator_range(object sequence, Iterator start, Iterator finish); | |
44 | ||
45 | typedef boost::detail::iterator_traits<Iterator> traits_t; | |
46 | ||
47 | struct next | |
48 | { | |
49 | typedef typename mpl::if_< | |
50 | is_reference< | |
51 | typename traits_t::reference | |
52 | > | |
53 | , typename traits_t::reference | |
54 | , typename traits_t::value_type | |
55 | >::type result_type; | |
56 | ||
57 | result_type | |
58 | operator()(iterator_range<NextPolicies,Iterator>& self) | |
59 | { | |
60 | if (self.m_start == self.m_finish) | |
61 | stop_iteration_error(); | |
62 | return *self.m_start++; | |
63 | } | |
64 | ||
65 | # if BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003)) | |
66 | // CWPro8 has a codegen problem when this is an empty class | |
67 | int garbage; | |
68 | # endif | |
69 | }; | |
70 | ||
71 | typedef next next_fn; | |
72 | ||
73 | object m_sequence; // Keeps the sequence alive while iterating. | |
74 | Iterator m_start; | |
75 | Iterator m_finish; | |
76 | }; | |
77 | ||
78 | namespace detail | |
79 | { | |
80 | // Get a Python class which contains the given iterator and | |
81 | // policies, creating it if necessary. Requires: NextPolicies is | |
82 | // default-constructible. | |
83 | template <class Iterator, class NextPolicies> | |
84 | object demand_iterator_class(char const* name, Iterator* = 0, NextPolicies const& policies = NextPolicies()) | |
85 | { | |
86 | typedef iterator_range<NextPolicies,Iterator> range_; | |
87 | ||
88 | // Check the registry. If one is already registered, return it. | |
89 | handle<> class_obj( | |
90 | objects::registered_class_object(python::type_id<range_>())); | |
91 | ||
92 | if (class_obj.get() != 0) | |
93 | return object(class_obj); | |
94 | ||
95 | typedef typename range_::next_fn next_fn; | |
96 | typedef typename next_fn::result_type result_type; | |
97 | ||
98 | return class_<range_>(name, no_init) | |
99 | .def("__iter__", identity_function()) | |
100 | .def( | |
101 | #if PY_VERSION_HEX >= 0x03000000 | |
102 | "__next__" | |
103 | #else | |
104 | "next" | |
105 | #endif | |
106 | , make_function( | |
107 | next_fn() | |
108 | , policies | |
109 | , mpl::vector2<result_type,range_&>() | |
110 | )); | |
111 | } | |
112 | ||
113 | // A function object which builds an iterator_range. | |
114 | template < | |
115 | class Target | |
116 | , class Iterator | |
117 | , class Accessor1 | |
118 | , class Accessor2 | |
119 | , class NextPolicies | |
120 | > | |
121 | struct py_iter_ | |
122 | { | |
123 | py_iter_(Accessor1 const& get_start, Accessor2 const& get_finish) | |
124 | : m_get_start(get_start) | |
125 | , m_get_finish(get_finish) | |
126 | {} | |
127 | ||
128 | // Extract an object x of the Target type from the first Python | |
129 | // argument, and invoke get_start(x)/get_finish(x) to produce | |
130 | // iterators, which are used to construct a new iterator_range<> | |
131 | // object that gets wrapped into a Python iterator. | |
132 | iterator_range<NextPolicies,Iterator> | |
133 | operator()(back_reference<Target&> x) const | |
134 | { | |
135 | // Make sure the Python class is instantiated. | |
136 | detail::demand_iterator_class("iterator", (Iterator*)0, NextPolicies()); | |
137 | ||
138 | return iterator_range<NextPolicies,Iterator>( | |
139 | x.source() | |
140 | , m_get_start(x.get()) | |
141 | , m_get_finish(x.get()) | |
142 | ); | |
143 | } | |
144 | private: | |
145 | Accessor1 m_get_start; | |
146 | Accessor2 m_get_finish; | |
147 | }; | |
148 | ||
149 | template <class Target, class Iterator, class NextPolicies, class Accessor1, class Accessor2> | |
150 | inline object make_iterator_function( | |
151 | Accessor1 const& get_start | |
152 | , Accessor2 const& get_finish | |
153 | , NextPolicies const& /*next_policies*/ | |
154 | , Iterator const& (*)() | |
155 | , boost::type<Target>* | |
156 | , int | |
157 | ) | |
158 | { | |
159 | return make_function( | |
160 | py_iter_<Target,Iterator,Accessor1,Accessor2,NextPolicies>(get_start, get_finish) | |
161 | , default_call_policies() | |
162 | , mpl::vector2<iterator_range<NextPolicies,Iterator>, back_reference<Target&> >() | |
163 | ); | |
164 | } | |
165 | ||
166 | template <class Target, class Iterator, class NextPolicies, class Accessor1, class Accessor2> | |
167 | inline object make_iterator_function( | |
168 | Accessor1 const& get_start | |
169 | , Accessor2 const& get_finish | |
170 | , NextPolicies const& next_policies | |
171 | , Iterator& (*)() | |
172 | , boost::type<Target>* | |
173 | , ...) | |
174 | { | |
175 | return make_iterator_function( | |
176 | get_start | |
177 | , get_finish | |
178 | , next_policies | |
179 | , (Iterator const&(*)())0 | |
180 | , (boost::type<Target>*)0 | |
181 | , 0 | |
182 | ); | |
183 | } | |
184 | ||
185 | } | |
186 | ||
187 | // Create a Python callable object which accepts a single argument | |
188 | // convertible to the C++ Target type and returns a Python | |
189 | // iterator. The Python iterator uses get_start(x) and get_finish(x) | |
190 | // (where x is an instance of Target) to produce begin and end | |
191 | // iterators for the range, and an instance of NextPolicies is used as | |
192 | // CallPolicies for the Python iterator's next() function. | |
193 | template <class Target, class NextPolicies, class Accessor1, class Accessor2> | |
194 | inline object make_iterator_function( | |
195 | Accessor1 const& get_start | |
196 | , Accessor2 const& get_finish | |
197 | , NextPolicies const& next_policies | |
198 | , boost::type<Target>* = 0 | |
199 | ) | |
200 | { | |
201 | typedef typename Accessor1::result_type iterator; | |
b32b8144 FG |
202 | typedef typename boost::python::detail::add_const<iterator>::type iterator_const; |
203 | typedef typename boost::python::detail::add_lvalue_reference<iterator_const>::type iterator_cref; | |
7c673cae FG |
204 | |
205 | return detail::make_iterator_function( | |
206 | get_start | |
207 | , get_finish | |
208 | , next_policies | |
209 | , (iterator_cref(*)())0 | |
210 | , (boost::type<Target>*)0 | |
211 | , 0 | |
212 | ); | |
213 | } | |
214 | ||
215 | // | |
216 | // implementation | |
217 | // | |
218 | template <class NextPolicies, class Iterator> | |
219 | inline iterator_range<NextPolicies,Iterator>::iterator_range( | |
220 | object sequence, Iterator start, Iterator finish) | |
221 | : m_sequence(sequence), m_start(start), m_finish(finish) | |
222 | { | |
223 | } | |
224 | ||
225 | }}} // namespace boost::python::objects | |
226 | ||
227 | #endif // ITERATOR_DWA2002510_HPP |