public:

friend class sb_actor<fixed_stack>;

fixed_stack(size_t max) : max_size(max) {

full.assign(

[=](push_atom, int) {

/* discard */

},

[=](pop_atom) -> message {

auto result = data.back();

data.pop_back();

become(filled);

return make_message(ok_atom::value, result);

}

);

filled.assign(

[=](push_atom, int what) {

data.push_back(what);

if (data.size() == max_size) {

become(full);

}

},

[=](pop_atom) -> message {

auto result = data.back();

data.pop_back();

if (data.empty()) {

become(empty);

}

return make_message(ok_atom::value, result);

}

);

empty.assign(

[=](push_atom, int what) {

data.push_back(what);

become(filled);

},

[=](pop_atom) {

return error_atom::value;

}

);

}

~fixed_stack();

private:

size_t max_size = 10;

std::vector<int> data;

behavior full;

behavior filled;

behavior empty;

behavior& init_state = empty;

scoped_actor self;

auto st = spawn<fixed_stack>(size_t{10});

// push 20 values

for (int i = 0; i < 20; ++i) self->send(st, push_atom::value, i);

// pop 20 times

for (int i = 0; i < 20; ++i) self->send(st, pop_atom::value);

// expect 10 failure messages

{

int i = 0;

self->receive_for(i, 10) (

[](error_atom) {

CAF_CHECKPOINT();

}

);

CAF_CHECKPOINT();

}

// expect 10 {'ok', value} messages

{

std::vector<int> values;

int i = 0;

self->receive_for(i, 10) (

[&](ok_atom, int value) {

values.push_back(value);

}

);

std::vector<int> expected{9, 8, 7, 6, 5, 4, 3, 2, 1, 0};

CAF_CHECK_EQUAL(join(values, ","), join(expected, ","));

}

// terminate st

self->send_exit(st, exit_reason::user_shutdown);

self->await_all_other_actors_done();

CAF_TEST(test_fixed_stack_actor);

test_fixed_stack_actor();

shutdown();

return CAF_TEST_RESULT();