表类型

protobuf语言的maps字段类型相当于C++语言的std::map类型

工程目录结构

$ ls proto/
sample_maps.proto

proto文件

$ cat proto/sample_maps.proto
syntax = "proto3";

message home
{
    string addr = 1;
}

message sample_maps
{
    map<int32, string> ids = 1;
    map<string, home> infos = 2;
}

读写源文件

$ cat reader.cpp
#include <fstream>
#include <iostream>
#include "sample_maps.pb.h"

using namespace std;

int main(int argc, char *argv[])
{
    fstream input("./log", ios::in | ios::binary);
    cout << "Deserialize start." << endl;

    sample_maps m;
    if (!m.ParseFromIstream(&input))
    {
        cout << "Deserialize failed." << endl;
        return -1;
    }
    
    auto ids = m.ids();
    for (auto iter = ids.cbegin(); iter != ids.cend(); iter++)
        cout << iter->first << " : " << iter->second << endl; 
    
    auto infos = m.infos();
    for (auto iter = infos.cbegin(); iter != infos.cend(); iter++)
        cout << iter->first << " : " << iter->second.DebugString(); 

    cout << "Deserialize end." << endl;
    input.close();
    return 0;
}

$ cat writer.cpp
#include <fstream>
#include <iostream>
#include "sample_maps.pb.h"

using namespace std;

int main(int argc, char *argv[])
{
    sample_maps m;
    auto ids_ptr = m.mutable_ids();
    (*ids_ptr)[1] = "fwd";
    (*ids_ptr)[2] = "xb";

    auto infos_ptr = m.mutable_infos();
    home h;
    h.set_addr("nj");
    (*infos_ptr)["fwd"] = h;

    fstream output("./log", ios::out | ios::trunc | ios::binary); 
    cout << "Serialize start." << endl;
    if (!m.SerializeToOstream(&output))
        {
                cout << "Serialize failed." << endl;
                return -1;
        }
    output.close();
    cout << "Serialize end." << endl;
    return 0;
}