| // -*- C++ -*- |
| //===----------------------------------------------------------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is dual licensed under the MIT and the University of Illinois Open |
| // Source Licenses. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| // UNSUPPORTED: c++98, c++03, c++11 |
| |
| #include <experimental/coroutine> |
| #include <cassert> |
| |
| using namespace std::experimental; |
| |
| bool cancel = false; |
| |
| struct goroutine |
| { |
| static int const N = 10; |
| static int count; |
| static coroutine_handle<> stack[N]; |
| |
| static void schedule(coroutine_handle<>& rh) |
| { |
| assert(count < N); |
| stack[count++] = rh; |
| rh = nullptr; |
| } |
| |
| ~goroutine() {} |
| |
| static void go(goroutine) {} |
| |
| static void run_one() |
| { |
| assert(count > 0); |
| stack[--count](); |
| } |
| |
| struct promise_type |
| { |
| suspend_never initial_suspend() { |
| return {}; |
| } |
| suspend_never final_suspend() { |
| return {}; |
| } |
| void return_void() {} |
| goroutine get_return_object() { |
| return{}; |
| } |
| void unhandled_exception() {} |
| }; |
| }; |
| int goroutine::count; |
| coroutine_handle<> goroutine::stack[N]; |
| |
| coroutine_handle<goroutine::promise_type> workaround; |
| |
| class channel; |
| |
| struct push_awaiter { |
| channel* ch; |
| bool await_ready() {return false; } |
| void await_suspend(coroutine_handle<> rh); |
| void await_resume() {} |
| }; |
| |
| struct pull_awaiter { |
| channel * ch; |
| |
| bool await_ready(); |
| void await_suspend(coroutine_handle<> rh); |
| int await_resume(); |
| }; |
| |
| class channel |
| { |
| using T = int; |
| |
| friend struct push_awaiter; |
| friend struct pull_awaiter; |
| |
| T const* pvalue = nullptr; |
| coroutine_handle<> reader = nullptr; |
| coroutine_handle<> writer = nullptr; |
| public: |
| push_awaiter push(T const& value) |
| { |
| assert(pvalue == nullptr); |
| assert(!writer); |
| pvalue = &value; |
| |
| return { this }; |
| } |
| |
| pull_awaiter pull() |
| { |
| assert(!reader); |
| |
| return { this }; |
| } |
| |
| void sync_push(T const& value) |
| { |
| assert(!pvalue); |
| pvalue = &value; |
| assert(reader); |
| reader(); |
| assert(!pvalue); |
| reader = nullptr; |
| } |
| |
| auto sync_pull() |
| { |
| while (!pvalue) goroutine::run_one(); |
| auto result = *pvalue; |
| pvalue = nullptr; |
| if (writer) |
| { |
| auto wr = writer; |
| writer = nullptr; |
| wr(); |
| } |
| return result; |
| } |
| }; |
| |
| void push_awaiter::await_suspend(coroutine_handle<> rh) |
| { |
| ch->writer = rh; |
| if (ch->reader) goroutine::schedule(ch->reader); |
| } |
| |
| |
| bool pull_awaiter::await_ready() { |
| return !!ch->writer; |
| } |
| void pull_awaiter::await_suspend(coroutine_handle<> rh) { |
| ch->reader = rh; |
| } |
| int pull_awaiter::await_resume() { |
| auto result = *ch->pvalue; |
| ch->pvalue = nullptr; |
| if (ch->writer) { |
| //goroutine::schedule(ch->writer); |
| auto wr = ch->writer; |
| ch->writer = nullptr; |
| wr(); |
| } |
| return result; |
| } |
| |
| goroutine pusher(channel& left, channel& right) |
| { |
| for (;;) { |
| auto val = co_await left.pull(); |
| co_await right.push(val + 1); |
| } |
| } |
| |
| const int N = 100; |
| channel* c = new channel[N + 1]; |
| |
| int main() { |
| for (int i = 0; i < N; ++i) |
| goroutine::go(pusher(c[i], c[i + 1])); |
| |
| c[0].sync_push(0); |
| int result = c[N].sync_pull(); |
| |
| assert(result == 100); |
| } |