void operator()

in demo_example/asio/asio/impl/read_until.hpp [1143:1235]
74 lines of code
15 McCabe index (conditional complexity)

    void operator()(asio::error_code ec,
        std::size_t bytes_transferred, int start = 0)
    {
      const std::size_t not_found = (std::numeric_limits<std::size_t>::max)();
      std::size_t bytes_to_read;
      switch (start_ = start)
      {
      case 1:
        for (;;)
        {
          {
            // Determine the range of the data to be searched.
            typedef typename DynamicBuffer_v1::const_buffers_type
              buffers_type;
            typedef buffers_iterator<buffers_type> iterator;
            buffers_type data_buffers = buffers_.data();
            iterator begin = iterator::begin(data_buffers);
            iterator start_pos = begin + search_position_;
            iterator end = iterator::end(data_buffers);

            // Look for a match.
            std::pair<iterator, bool> result = detail::partial_search(
                start_pos, end, delim_.begin(), delim_.end());
            if (result.first != end && result.second)
            {
              // Full match. We're done.
              search_position_ = result.first - begin + delim_.length();
              bytes_to_read = 0;
            }

            // No match yet. Check if buffer is full.
            else if (buffers_.size() == buffers_.max_size())
            {
              search_position_ = not_found;
              bytes_to_read = 0;
            }

            // Need to read some more data.
            else
            {
              if (result.first != end)
              {
                // Partial match. Next search needs to start from beginning of
                // match.
                search_position_ = result.first - begin;
              }
              else
              {
                // Next search can start with the new data.
                search_position_ = end - begin;
              }

              bytes_to_read = std::min<std::size_t>(
                    std::max<std::size_t>(512,
                      buffers_.capacity() - buffers_.size()),
                    std::min<std::size_t>(65536,
                      buffers_.max_size() - buffers_.size()));
            }
          }

          // Check if we're done.
          if (!start && bytes_to_read == 0)
            break;

          // Start a new asynchronous read operation to obtain more data.
          {
            ASIO_HANDLER_LOCATION((
                  __FILE__, __LINE__, "async_read_until"));
            stream_.async_read_some(buffers_.prepare(bytes_to_read),
                ASIO_MOVE_CAST(read_until_delim_string_op_v1)(*this));
          }
          return; default:
          buffers_.commit(bytes_transferred);
          if (ec || bytes_transferred == 0)
            break;
          if (this->cancelled() != cancellation_type::none)
          {
            ec = error::operation_aborted;
            break;
          }
        }

        const asio::error_code result_ec =
          (search_position_ == not_found)
          ? error::not_found : ec;

        const std::size_t result_n =
          (ec || search_position_ == not_found)
          ? 0 : search_position_;

        ASIO_MOVE_OR_LVALUE(ReadHandler)(handler_)(result_ec, result_n);
      }
    }