1 | #include "base.hpp" |
---|
2 | |
---|
3 | #include <algorithm> |
---|
4 | #include <iterator> |
---|
5 | #include <vector> |
---|
6 | |
---|
7 | template<typename T> |
---|
8 | struct cor_range { |
---|
9 | struct promise_type { |
---|
10 | T _value; |
---|
11 | |
---|
12 | cor_range get_return_object() { |
---|
13 | return cor_range(std::experimental::coroutine_handle<promise_type>::from_promise(*this)); |
---|
14 | } |
---|
15 | |
---|
16 | auto initial_suspend() { return suspend_always(); } |
---|
17 | auto final_suspend() { return suspend_always(); } |
---|
18 | |
---|
19 | void return_value(T value) { |
---|
20 | _value = value; |
---|
21 | } |
---|
22 | |
---|
23 | auto yield_value(T value) { |
---|
24 | _value = value; |
---|
25 | return suspend_always(); |
---|
26 | } |
---|
27 | |
---|
28 | void unhandled_exception() {} |
---|
29 | }; |
---|
30 | |
---|
31 | std::experimental::coroutine_handle<promise_type> _coroutine = nullptr; |
---|
32 | |
---|
33 | explicit cor_range(std::experimental::coroutine_handle<promise_type> coroutine) |
---|
34 | : _coroutine(coroutine) |
---|
35 | {} |
---|
36 | |
---|
37 | ~cor_range() { |
---|
38 | if(_coroutine) { _coroutine.destroy(); } |
---|
39 | } |
---|
40 | |
---|
41 | cor_range() = default; |
---|
42 | cor_range(cor_range const &) = delete; |
---|
43 | cor_range& operator=(cor_range const &) = delete; |
---|
44 | |
---|
45 | cor_range(cor_range&& other) { |
---|
46 | std::swap(_coroutine, other._coroutine); |
---|
47 | } |
---|
48 | |
---|
49 | cor_range& operator=(cor_range&& other) { |
---|
50 | if(&other != this) { |
---|
51 | _coroutine = other._coroutine; |
---|
52 | other._coroutine = nullptr; |
---|
53 | } |
---|
54 | return *this; |
---|
55 | } |
---|
56 | |
---|
57 | T next() { |
---|
58 | _coroutine.resume(); |
---|
59 | return _coroutine.promise()._value; |
---|
60 | } |
---|
61 | |
---|
62 | struct iterator : std::iterator<std::input_iterator_tag, T> { |
---|
63 | std::experimental::coroutine_handle<promise_type> _coroutine = nullptr; |
---|
64 | |
---|
65 | iterator() = default; |
---|
66 | explicit iterator(std::experimental::coroutine_handle<promise_type> coroutine) |
---|
67 | : _coroutine(coroutine) |
---|
68 | {} |
---|
69 | |
---|
70 | iterator& operator++() { |
---|
71 | _coroutine.resume(); |
---|
72 | return *this; |
---|
73 | } |
---|
74 | |
---|
75 | T const & operator*() const { |
---|
76 | return _coroutine.promise()._value; |
---|
77 | } |
---|
78 | }; |
---|
79 | |
---|
80 | iterator begin() { |
---|
81 | if(_coroutine) { |
---|
82 | _coroutine.resume(); |
---|
83 | if(_coroutine.done()) { return end(); } |
---|
84 | } |
---|
85 | |
---|
86 | return iterator{ _coroutine }; |
---|
87 | } |
---|
88 | |
---|
89 | iterator end() { return iterator{}; } |
---|
90 | }; |
---|
91 | |
---|
92 | cor_range<int> fib() { |
---|
93 | int fn; |
---|
94 | fn = 0; int fn1 = fn; co_yield fn; |
---|
95 | fn = 1; int fn2 = fn1; fn1 = fn; co_yield fn; |
---|
96 | for(;;) { |
---|
97 | fn = fn1 + fn2; fn2 = fn1; fn1 = fn; co_yield fn; |
---|
98 | } |
---|
99 | } |
---|
100 | |
---|
101 | int main() { |
---|
102 | { |
---|
103 | auto f1 = fib(); |
---|
104 | auto f2 = fib(); |
---|
105 | for(int i = 0; i < 10; i++) { |
---|
106 | std::cout << f1.next() << " " << f2.next() << std::endl; |
---|
107 | } |
---|
108 | } |
---|
109 | |
---|
110 | { |
---|
111 | auto f1 = fib(); |
---|
112 | std::vector<int> fibs; |
---|
113 | std::copy_n(f1.begin(), 10, std::back_inserter(fibs)); |
---|
114 | |
---|
115 | for(auto i : fibs) { |
---|
116 | std::cout << i << std::endl; |
---|
117 | } |
---|
118 | } |
---|
119 | } |
---|