├── Makefile
├── README.md
└── coroutine.cpp


/Makefile:
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1 | 
2 | coroutine: coroutine.cpp
3 | 


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/README.md:
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1 | A super-simple "Lua-like" coroutine implementation for C++. 
2 | 
3 | To run the sample, download it and type "make."  Then run "./coroutine."
4 | 
5 | If you're interested in this, check out my [coro](https://github.com/mfichman/coro.git) library, which is much more robust and includes an asynchronous socket library.
6 | 


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/coroutine.cpp:
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 1 | 
 2 | #include <iostream>
 3 | #include <vector>
 4 | #include <cstring>
 5 | #include <ucontext.h>
 6 | 
 7 | class Coroutine {
 8 | 
 9 | public:
10 |     typedef void (*Function)(void);
11 |     enum Status { NEW, RUNNING, FINISHED };
12 | 
13 |     Coroutine(Function function) : 
14 |         status_(NEW),
15 |         stack_(4096) {
16 |         
17 |         getcontext(&context_);
18 |         context_.uc_stack.ss_sp = &stack_[0]; 
19 |         context_.uc_stack.ss_size = stack_.size();
20 |         context_.uc_link = 0;
21 |         makecontext(&context_, function, 0);
22 |     }
23 | 
24 |     void resume() {
25 |         if (FINISHED == status_) {
26 |             return;
27 |         }
28 |         if (NEW == status_) {
29 |             status_ = RUNNING;
30 |         }
31 |         
32 |         ucontext_t save = caller_;
33 | 
34 |         // The caller context becomes the current context
35 |         swapcontext(&caller_, &context_);
36 |         context_ = callee_;
37 | 
38 |         caller_ = save;
39 |     }
40 | 
41 |     static void yield() {
42 |         // The current context becomes the caller
43 |         swapcontext(&callee_, &caller_);
44 |     }
45 | 
46 |     static ucontext_t caller_;
47 |     static ucontext_t callee_;
48 | 
49 | private:
50 |     Status status_;
51 |     ucontext_t context_;
52 |     std::vector<char> stack_;
53 | 
54 | };
55 | 
56 | ucontext_t Coroutine::caller_;
57 | ucontext_t Coroutine::callee_;
58 | 
59 | void g() {
60 |     std::cout << "x" << std::endl;
61 |     Coroutine::yield();
62 |     std::cout << "z" << std::endl;
63 | }
64 | 
65 | void f() {
66 |     Coroutine co(g);
67 |     co.resume();
68 | 
69 |     std::cout << "a" << std::endl;
70 |     Coroutine::yield();
71 |     std::cout << "b" << std::endl;
72 |     Coroutine::yield();
73 |     std::cout << "c" << std::endl;
74 |     
75 |     co.resume();
76 | }
77 | 
78 | int main(int argc, char** argv) {
79 |     Coroutine co(f);
80 |     co.resume();
81 |     co.resume();
82 |     co.resume();
83 |     std::cout << "DONE" << std::endl;
84 |     return 0;
85 | 
86 | }
87 | 


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