std::unique_ptr Decoder::decode()

in hessian2/basic_codec/list_codec.cc [108:187]

• 72 lines of code
• 22 McCabe index (conditional complexity)

std::unique_ptr<UntypedListObject> Decoder::decode() {
  Object::UntypedList obj_list;

  auto result = std::make_unique<UntypedListObject>();
  values_ref_.push_back(result.get());

  auto ret = reader_->read<uint8_t>();
  if (!ret.first) {
    return nullptr;
  }

  auto code = ret.second;

  auto ReadNumsObject = [&](int nums) -> bool {
    for (int i = 0; i < nums; i++) {
      auto o = decode<Object>();
      if (!o) {
        return false;
      }
      obj_list.emplace_back(std::move(o));
    }
    return true;
  };

  auto ReadObjectUntilEnd = [&]() -> bool {
    auto ret = reader_->peek<uint8_t>();
    if (!ret.first) {
      return false;
    }

    while (ret.second != 'Z') {
      auto o = decode<Object>();
      if (!o) {
        return false;
      }
      obj_list.emplace_back(std::move(o));
      ret = reader_->peek<uint8_t>();
      if (!ret.first) {
        return false;
      }
    }
    // Skip last 'Z'
    reader_->read<uint8_t>();
    return true;
  };

  switch (code) {
    case 0x57: {
      if (!ReadObjectUntilEnd()) {
        return nullptr;
      }
      break;
    }
    case 0x58: {
      auto ret = decode<int32_t>();
      if (!ret) {
        return nullptr;
      }
      if (!ReadNumsObject(*ret)) {
        return nullptr;
      }
      break;
    }
    case 0x78:
    case 0x79:
    case 0x7a:
    case 0x7b:
    case 0x7c:
    case 0x7d:
    case 0x7e:
    case 0x7f: {
      if (!ReadNumsObject(code - 0x78)) {
        return nullptr;
      }
      break;
    }
  }
  result->setUntypedList(std::move(obj_list));
  return result;
}