Decoder shared_ptr (cpp)

decoder.cpp

#include <memory>
#include <vector>

class Decoder {
    public:
        void init(std::shared_ptr<std::vector<unsigned char>> s_buffer) {
            buffer = s_buffer;
        }

    void decode(unsigned char* data, uint32_t size) {
        auto b = buffer.get();
        if (size == 10) {
            b->insert(b->end(), data, data + size);
        } else {
            b->insert(b->end(), data, data + size);
        }
    }

    private:
        std::shared_ptr<std::vector<unsigned char>> buffer = nullptr;
};

unsigned char big_data[10]{5};
unsigned char small_data[5]{4};

class Link {

    public:

      Link(Decoder decoder_) : decoder(decoder_) {
          buffer->reserve(4990);
          decoder.init(buffer);
      }

      void process(bool big) {
          if (big) {
              decoder.decode(big_data, 10);
          } else {
            decoder.decode(small_data, 4);
          }
      }

    private:
      Decoder decoder;
      std::shared_ptr<std::vector<unsigned char>> buffer;
};

int main() {
    Decoder decoder{};
    Link link{decoder};
    link.process(false);
    link.process(false);
    link.process(false);
    link.process(false);
    link.process(false);
    link.process(true);
}