CODEWITHSUNDEEP
c++protocol-buffers
aajkaltak
aajkaltak

Reputation: 1537

How do you add a repeated field using Google's Protocol Buffer in C++?

I have the below protocol buffer. Note that StockStatic is a repeated field.

message ServiceResponse
{
    enum Type
    {
        REQUEST_FAILED = 1;
        STOCK_STATIC_SNAPSHOT = 2;
    }

    message StockStaticSnapshot
    {
        repeated StockStatic stock_static = 1;
    }
    required Type type = 1;
    optional StockStaticSnapshot stock_static_snapshot = 2;
}

message StockStatic
{
    optional string sector      = 1;
    optional string subsector   = 2;
}

I am filling out the StockStatic fields while iterating through a vector.

ServiceResponse.set_type(ServiceResponse_Type_STOCK_STATIC_SNAPSHOT);

ServiceResponse_StockStaticSnapshot stockStaticSnapshot;

for (vector<stockStaticInfo>::iterator it = m_staticStocks.begin(); it!= m_staticStocks.end(); ++it)
{
    StockStatic* pStockStaticEntity = stockStaticSnapshot.add_stock_static();

    SetStockStaticProtoFields(*it, pStockStaticEntity); // sets sector and subsector field to pStockStaticEntity by reading the fields using (*it)
}

But the above code is right only if StockStatic was an optional field and not a repeated field. My questions is what line of code am i missing to make it a repeated field?

Upvotes: 39

Views: 92365

Answers (3)

leegent
leegent

Reputation: 964

No, you're doing the right thing.

Here's a snippet of my protocol buffer (details omitted for brevity):

message DemandSummary
{
    required uint32 solutionIndex     = 1;
    required uint32 demandID          = 2;
}
message ComputeResponse
{
    repeated DemandSummary solutionInfo  = 3;
}

...and the C++ to fill up ComputeResponse::solutionInfo:

ComputeResponse response;

for ( int i = 0; i < demList.size(); ++i ) {

    DemandSummary* summary = response.add_solutioninfo();
    summary->set_solutionindex(solutionID);
    summary->set_demandid(demList[i].toUInt());
}

response.solutionInfo now contains demList.size() elements.

Upvotes: 57

vrqq
vrqq

Reputation: 576

Here the c++ sample code but may not efficient:

message MyArray
{
    repeated uint64 my_data = 1;
}

//Copy
std::array<unsigned long long, 5> test={1,1,2,3,5};
mynamespace::MyArray pbvar;
auto *dst_ptr = keys.my_data();
google::protobuf::RepeatedField<google::protobuf::uint64> field{test.begin(), test.end()};
dst_ptr->CopyFrom(field);

//Output
for (auto it : pbvar.my_data())
    std::cout<<it<<" ";
std::cout<<std::endl;

Upvotes: 0

VNarasimhaM
VNarasimhaM

Reputation: 1570

Another way of accomplishing the same thing:

message SearchResponse {
  message Result {
  required string url = 1;
  optional string title = 2;
  repeated string snippets = 3;
  }  
  repeated Result result = 1;
}

Upvotes: -2

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