1 /*
2 tests/test_sequences_and_iterators.cpp -- supporting Pythons' sequence protocol, iterators,
3 etc.
4
5 Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>
6
7 All rights reserved. Use of this source code is governed by a
8 BSD-style license that can be found in the LICENSE file.
9 */
10
11 #include "pybind11_tests.h"
12 #include "constructor_stats.h"
13 #include <pybind11/operators.h>
14 #include <pybind11/stl.h>
15
16 template<typename T>
17 class NonZeroIterator {
18 const T* ptr_;
19 public:
NonZeroIterator(const T * ptr)20 NonZeroIterator(const T* ptr) : ptr_(ptr) {}
operator *() const21 const T& operator*() const { return *ptr_; }
operator ++()22 NonZeroIterator& operator++() { ++ptr_; return *this; }
23 };
24
25 class NonZeroSentinel {};
26
27 template<typename A, typename B>
operator ==(const NonZeroIterator<std::pair<A,B>> & it,const NonZeroSentinel &)28 bool operator==(const NonZeroIterator<std::pair<A, B>>& it, const NonZeroSentinel&) {
29 return !(*it).first || !(*it).second;
30 }
31
32 template <typename PythonType>
test_random_access_iterator(PythonType x)33 py::list test_random_access_iterator(PythonType x) {
34 if (x.size() < 5)
35 throw py::value_error("Please provide at least 5 elements for testing.");
36
37 auto checks = py::list();
38 auto assert_equal = [&checks](py::handle a, py::handle b) {
39 auto result = PyObject_RichCompareBool(a.ptr(), b.ptr(), Py_EQ);
40 if (result == -1) { throw py::error_already_set(); }
41 checks.append(result != 0);
42 };
43
44 auto it = x.begin();
45 assert_equal(x[0], *it);
46 assert_equal(x[0], it[0]);
47 assert_equal(x[1], it[1]);
48
49 assert_equal(x[1], *(++it));
50 assert_equal(x[1], *(it++));
51 assert_equal(x[2], *it);
52 assert_equal(x[3], *(it += 1));
53 assert_equal(x[2], *(--it));
54 assert_equal(x[2], *(it--));
55 assert_equal(x[1], *it);
56 assert_equal(x[0], *(it -= 1));
57
58 assert_equal(it->attr("real"), x[0].attr("real"));
59 assert_equal((it + 1)->attr("real"), x[1].attr("real"));
60
61 assert_equal(x[1], *(it + 1));
62 assert_equal(x[1], *(1 + it));
63 it += 3;
64 assert_equal(x[1], *(it - 2));
65
66 checks.append(static_cast<std::size_t>(x.end() - x.begin()) == x.size());
67 checks.append((x.begin() + static_cast<std::ptrdiff_t>(x.size())) == x.end());
68 checks.append(x.begin() < x.end());
69
70 return checks;
71 }
72
TEST_SUBMODULE(sequences_and_iterators,m)73 TEST_SUBMODULE(sequences_and_iterators, m) {
74 // test_sliceable
75 class Sliceable{
76 public:
77 Sliceable(int n): size(n) {}
78 int start,stop,step;
79 int size;
80 };
81 py::class_<Sliceable>(m,"Sliceable")
82 .def(py::init<int>())
83 .def("__getitem__",[](const Sliceable &s, py::slice slice) {
84 ssize_t start, stop, step, slicelength;
85 if (!slice.compute(s.size, &start, &stop, &step, &slicelength))
86 throw py::error_already_set();
87 int istart = static_cast<int>(start);
88 int istop = static_cast<int>(stop);
89 int istep = static_cast<int>(step);
90 return std::make_tuple(istart,istop,istep);
91 })
92 ;
93
94 // test_sequence
95 class Sequence {
96 public:
97 Sequence(size_t size) : m_size(size) {
98 print_created(this, "of size", m_size);
99 m_data = new float[size];
100 memset(m_data, 0, sizeof(float) * size);
101 }
102 Sequence(const std::vector<float> &value) : m_size(value.size()) {
103 print_created(this, "of size", m_size, "from std::vector");
104 m_data = new float[m_size];
105 memcpy(m_data, &value[0], sizeof(float) * m_size);
106 }
107 Sequence(const Sequence &s) : m_size(s.m_size) {
108 print_copy_created(this);
109 m_data = new float[m_size];
110 memcpy(m_data, s.m_data, sizeof(float)*m_size);
111 }
112 Sequence(Sequence &&s) : m_size(s.m_size), m_data(s.m_data) {
113 print_move_created(this);
114 s.m_size = 0;
115 s.m_data = nullptr;
116 }
117
118 ~Sequence() { print_destroyed(this); delete[] m_data; }
119
120 Sequence &operator=(const Sequence &s) {
121 if (&s != this) {
122 delete[] m_data;
123 m_size = s.m_size;
124 m_data = new float[m_size];
125 memcpy(m_data, s.m_data, sizeof(float)*m_size);
126 }
127 print_copy_assigned(this);
128 return *this;
129 }
130
131 Sequence &operator=(Sequence &&s) {
132 if (&s != this) {
133 delete[] m_data;
134 m_size = s.m_size;
135 m_data = s.m_data;
136 s.m_size = 0;
137 s.m_data = nullptr;
138 }
139 print_move_assigned(this);
140 return *this;
141 }
142
143 bool operator==(const Sequence &s) const {
144 if (m_size != s.size()) return false;
145 for (size_t i = 0; i < m_size; ++i)
146 if (m_data[i] != s[i])
147 return false;
148 return true;
149 }
150 bool operator!=(const Sequence &s) const { return !operator==(s); }
151
152 float operator[](size_t index) const { return m_data[index]; }
153 float &operator[](size_t index) { return m_data[index]; }
154
155 bool contains(float v) const {
156 for (size_t i = 0; i < m_size; ++i)
157 if (v == m_data[i])
158 return true;
159 return false;
160 }
161
162 Sequence reversed() const {
163 Sequence result(m_size);
164 for (size_t i = 0; i < m_size; ++i)
165 result[m_size - i - 1] = m_data[i];
166 return result;
167 }
168
169 size_t size() const { return m_size; }
170
171 const float *begin() const { return m_data; }
172 const float *end() const { return m_data+m_size; }
173
174 private:
175 size_t m_size;
176 float *m_data;
177 };
178 py::class_<Sequence>(m, "Sequence")
179 .def(py::init<size_t>())
180 .def(py::init<const std::vector<float>&>())
181 /// Bare bones interface
182 .def("__getitem__", [](const Sequence &s, size_t i) {
183 if (i >= s.size()) throw py::index_error();
184 return s[i];
185 })
186 .def("__setitem__", [](Sequence &s, size_t i, float v) {
187 if (i >= s.size()) throw py::index_error();
188 s[i] = v;
189 })
190 .def("__len__", &Sequence::size)
191 /// Optional sequence protocol operations
192 .def("__iter__", [](const Sequence &s) { return py::make_iterator(s.begin(), s.end()); },
193 py::keep_alive<0, 1>() /* Essential: keep object alive while iterator exists */)
194 .def("__contains__", [](const Sequence &s, float v) { return s.contains(v); })
195 .def("__reversed__", [](const Sequence &s) -> Sequence { return s.reversed(); })
196 /// Slicing protocol (optional)
197 .def("__getitem__", [](const Sequence &s, py::slice slice) -> Sequence* {
198 size_t start, stop, step, slicelength;
199 if (!slice.compute(s.size(), &start, &stop, &step, &slicelength))
200 throw py::error_already_set();
201 Sequence *seq = new Sequence(slicelength);
202 for (size_t i = 0; i < slicelength; ++i) {
203 (*seq)[i] = s[start]; start += step;
204 }
205 return seq;
206 })
207 .def("__setitem__", [](Sequence &s, py::slice slice, const Sequence &value) {
208 size_t start, stop, step, slicelength;
209 if (!slice.compute(s.size(), &start, &stop, &step, &slicelength))
210 throw py::error_already_set();
211 if (slicelength != value.size())
212 throw std::runtime_error("Left and right hand size of slice assignment have different sizes!");
213 for (size_t i = 0; i < slicelength; ++i) {
214 s[start] = value[i]; start += step;
215 }
216 })
217 /// Comparisons
218 .def(py::self == py::self)
219 .def(py::self != py::self)
220 // Could also define py::self + py::self for concatenation, etc.
221 ;
222
223 // test_map_iterator
224 // Interface of a map-like object that isn't (directly) an unordered_map, but provides some basic
225 // map-like functionality.
226 class StringMap {
227 public:
228 StringMap() = default;
229 StringMap(std::unordered_map<std::string, std::string> init)
230 : map(std::move(init)) {}
231
232 void set(std::string key, std::string val) { map[key] = val; }
233 std::string get(std::string key) const { return map.at(key); }
234 size_t size() const { return map.size(); }
235 private:
236 std::unordered_map<std::string, std::string> map;
237 public:
238 decltype(map.cbegin()) begin() const { return map.cbegin(); }
239 decltype(map.cend()) end() const { return map.cend(); }
240 };
241 py::class_<StringMap>(m, "StringMap")
242 .def(py::init<>())
243 .def(py::init<std::unordered_map<std::string, std::string>>())
244 .def("__getitem__", [](const StringMap &map, std::string key) {
245 try { return map.get(key); }
246 catch (const std::out_of_range&) {
247 throw py::key_error("key '" + key + "' does not exist");
248 }
249 })
250 .def("__setitem__", &StringMap::set)
251 .def("__len__", &StringMap::size)
252 .def("__iter__", [](const StringMap &map) { return py::make_key_iterator(map.begin(), map.end()); },
253 py::keep_alive<0, 1>())
254 .def("items", [](const StringMap &map) { return py::make_iterator(map.begin(), map.end()); },
255 py::keep_alive<0, 1>())
256 ;
257
258 // test_generalized_iterators
259 class IntPairs {
260 public:
261 IntPairs(std::vector<std::pair<int, int>> data) : data_(std::move(data)) {}
262 const std::pair<int, int>* begin() const { return data_.data(); }
263 private:
264 std::vector<std::pair<int, int>> data_;
265 };
266 py::class_<IntPairs>(m, "IntPairs")
267 .def(py::init<std::vector<std::pair<int, int>>>())
268 .def("nonzero", [](const IntPairs& s) {
269 return py::make_iterator(NonZeroIterator<std::pair<int, int>>(s.begin()), NonZeroSentinel());
270 }, py::keep_alive<0, 1>())
271 .def("nonzero_keys", [](const IntPairs& s) {
272 return py::make_key_iterator(NonZeroIterator<std::pair<int, int>>(s.begin()), NonZeroSentinel());
273 }, py::keep_alive<0, 1>())
274 ;
275
276
277 #if 0
278 // Obsolete: special data structure for exposing custom iterator types to python
279 // kept here for illustrative purposes because there might be some use cases which
280 // are not covered by the much simpler py::make_iterator
281
282 struct PySequenceIterator {
283 PySequenceIterator(const Sequence &seq, py::object ref) : seq(seq), ref(ref) { }
284
285 float next() {
286 if (index == seq.size())
287 throw py::stop_iteration();
288 return seq[index++];
289 }
290
291 const Sequence &seq;
292 py::object ref; // keep a reference
293 size_t index = 0;
294 };
295
296 py::class_<PySequenceIterator>(seq, "Iterator")
297 .def("__iter__", [](PySequenceIterator &it) -> PySequenceIterator& { return it; })
298 .def("__next__", &PySequenceIterator::next);
299
300 On the actual Sequence object, the iterator would be constructed as follows:
301 .def("__iter__", [](py::object s) { return PySequenceIterator(s.cast<const Sequence &>(), s); })
302 #endif
303
304 // test_python_iterator_in_cpp
305 m.def("object_to_list", [](py::object o) {
306 auto l = py::list();
307 for (auto item : o) {
308 l.append(item);
309 }
310 return l;
311 });
312
313 m.def("iterator_to_list", [](py::iterator it) {
314 auto l = py::list();
315 while (it != py::iterator::sentinel()) {
316 l.append(*it);
317 ++it;
318 }
319 return l;
320 });
321
322 // Make sure that py::iterator works with std algorithms
323 m.def("count_none", [](py::object o) {
324 return std::count_if(o.begin(), o.end(), [](py::handle h) { return h.is_none(); });
325 });
326
327 m.def("find_none", [](py::object o) {
328 auto it = std::find_if(o.begin(), o.end(), [](py::handle h) { return h.is_none(); });
329 return it->is_none();
330 });
331
332 m.def("count_nonzeros", [](py::dict d) {
333 return std::count_if(d.begin(), d.end(), [](std::pair<py::handle, py::handle> p) {
334 return p.second.cast<int>() != 0;
335 });
336 });
337
338 m.def("tuple_iterator", &test_random_access_iterator<py::tuple>);
339 m.def("list_iterator", &test_random_access_iterator<py::list>);
340 m.def("sequence_iterator", &test_random_access_iterator<py::sequence>);
341
342 // test_iterator_passthrough
343 // #181: iterator passthrough did not compile
344 m.def("iterator_passthrough", [](py::iterator s) -> py::iterator {
345 return py::make_iterator(std::begin(s), std::end(s));
346 });
347
348 // test_iterator_rvp
349 // #388: Can't make iterators via make_iterator() with different r/v policies
350 static std::vector<int> list = { 1, 2, 3 };
351 m.def("make_iterator_1", []() { return py::make_iterator<py::return_value_policy::copy>(list); });
352 m.def("make_iterator_2", []() { return py::make_iterator<py::return_value_policy::automatic>(list); });
353 }
354