protobuf-c中重复的子消息

Question

有没有人能给我举一个在protobuf-c中使用重复子消息打包\解包消息的例子

有关此问题的empty官方文档。

Answer 1

message B {
  required int64 i = 1;
};

message A {
  repeated B numbers = 1;
};

A a;
a.ParseFromString(<str>)
for (int i = 0; i < a.numbers_size(); ++i) {
  const B& b = a.numbers(i);
  printf("%d\n", b.i());
}

Answer 2

原件：

message SubMsg {
  bytes value = 1;
}

message MainMsg {
  repeated SubMsg msgs = 1;
}

pack (不要忘记释放内存( free (...)：

MainMsg mainMsg = { };
main_msg__init(&mainMsg);
SubMsg **subMsgs = calloc(LEN, sizeof(SubMsg*));
for (int i = 0; i < LEN; i++) {
    subMsgs[i] = calloc(1, sizeof(SubMsg));
    sub_msg__init(subMsgs[i]);
    subMsgs[i]->value.data = DATA;
    subMsgs[i]->value.len = DATALEN;
}
mainMsg.msgs = subMsgs;
mainMsg.n_msgs = LEN;
...
main_msg__pack(&mainMsg, BUFFER);

解包(不要忘记释放内存(..._free_unpacked(...))：

MainMsg* mainMsg = main_msg__unpack(nullptr, BUFFERLEN, BUFFER);
if (! mainMsg) {
    // error
    return;
}

SubMsg **subMsgs = mainMsg->msgs;
...

Answer 3

谷歌C++教程的“阅读消息”部分有相关的示例代码：http://code.google.com/apis/protocolbuffers/docs/cpptutorial.html

此外，STL的for_each似乎也工作正常(语法糖，或多或少)：std::for_each(a.numbers().begin()，a.numbers().end()，const B& b { std::cout << b.i() << std::endl；})；