Include already encoded CBOR

[Pique7]

Is there a way to include already encoded CBOR, e.g.:

std::vector<uint8_t> buf1; 
cbor::cbor_bytes_encoder encoder1(buf1);
encoder1.string_value("test1");
encoder1.flush();

std::vector<uint8_t> buf2; 
cbor::cbor_bytes_encoder encoder2(buf2);
encoder2.string_value("test2");

encoder2.raw_cbor(buf1);    // <-- I want something like this.

Maybe the encoder class is the wrong utility for this, but it is the only way I know to encode CBOR.
I haven't found anything helpful in the examples.

[Pique7]

I have found a possibility to achieve this myself:

std::vector<uint8_t> buf1; 
cbor::cbor_bytes_encoder encoder1(buf1);
encoder1.string_value("test1");
encoder1.flush();

std::vector<uint8_t> buf2; 
cbor::cbor_bytes_encoder encoder2(buf2);
encoder2.begin_array();
buf2.insert(buf2.end(), buf1.begin(), buf1.end());    // Just copy encoded CBOR directly to the vector buffer.
encoder2.string_value("test2");
encoder2.end_array();

Probably quite obvious but this solution has not immediately occured to me.
I don't know whether it covers all cases but for me it's sufficient enough.

[danielaparker]

@Pique7, Just to note, this solution will work for indefinite arrays, but not definite arrays, definite arrays keep track of how many items are added and will err if that doesn't match the prescribed length. See my answer for an approach that will work for both.

[danielaparker]

The supported way is to regenerate the events from buf1 and feed them to encoder2, e.g.

    std::vector<uint8_t> buf1;
    cbor::cbor_bytes_encoder encoder1(buf1);
    encoder1.string_value("test1");
    encoder1.flush();

    std::vector<uint8_t> buf2;
    cbor::cbor_bytes_encoder encoder2(buf2);
    encoder2.begin_array(2); // will also work for indefinite array (omitting length) 
    encoder2.string_value("test2");
    cbor::cbor_bytes_reader reader(buf1, encoder2); // feeds the string_value event into buf2
    reader.read();
    encoder2.end_array();
    encoder2.flush();

    auto j = cbor::decode_cbor<jsoncons::json>(buf2);
    std::cout << j << "\n";

Output:

["test2","test1"]

But if nobody's looking :-), you could always do a hack. For a definite or indefinite array, you can insert a 1 byte value, and then overwrite it with buf1, e.g.

    std::vector<uint8_t> buf1;
    cbor::cbor_bytes_encoder encoder1(buf1);
    encoder1.string_value("test1");
    encoder1.flush();

    std::vector<uint8_t> buf2;
    cbor::cbor_bytes_encoder encoder2(buf2);
    encoder2.begin_array(2);
    encoder2.string_value("test2");
    encoder2.null_value(); // insert one byte dummy value to track array length
    buf2.insert(buf2.end() - 1, buf1.begin(), buf1.end()); // override dummy value
    encoder2.end_array();
    encoder2.flush();

For an object, you can just append buf1 after a key.

[Pique7]

I think the first solution using cbor_bytes_reader is what I am looking for. Thanks a lot!