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
16template<typename T>
17class NonZeroIterator {
18    const T* ptr_;
19public:
20    NonZeroIterator(const T* ptr) : ptr_(ptr) {}
21    const T& operator*() const { return *ptr_; }
22    NonZeroIterator& operator++() { ++ptr_; return *this; }
23};
24
25class NonZeroSentinel {};
26
27template<typename A, typename B>
28bool operator==(const NonZeroIterator<std::pair<A, B>>& it, const NonZeroSentinel&) {
29    return !(*it).first || !(*it).second;
30}
31
32template <typename PythonType>
33py::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
73TEST_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