read_until.ipp

这是国外的resip协议栈

  if (iter != end)
  {
    // Found a match. We're done.
    asio::error_code ec;
    std::size_t bytes = iter.position() + 1;
    s.io_service().post(detail::bind_handler(handler, ec, bytes));
    return;
  }

  // No match. Check if buffer is full.
  if (b.size() == b.max_size())
  {
    asio::error_code ec(error::not_found);
    s.io_service().post(detail::bind_handler(handler, ec, 0));
    return;
  }

  // Start a new asynchronous read operation to obtain more data.
  std::size_t bytes_available =
    std::min<std::size_t>(512, b.max_size() - b.size());
  s.async_read_some(b.prepare(bytes_available),
      detail::read_until_delim_handler<AsyncReadStream, Allocator, ReadHandler>(
        s, b, delim, end.position(), handler));
}

namespace detail
{
  template <typename AsyncReadStream, typename Allocator, typename ReadHandler>
  class read_until_delim_string_handler
  {
  public:
    read_until_delim_string_handler(AsyncReadStream& stream,
        asio::basic_streambuf<Allocator>& streambuf,
        const std::string& delim, std::size_t next_search_start,
        ReadHandler handler)
      : stream_(stream),
        streambuf_(streambuf),
        delim_(delim),
        next_search_start_(next_search_start),
        handler_(handler)
    {
    }

    void operator()(const asio::error_code& ec,
        std::size_t bytes_transferred)
    {
      // Check for errors.
      if (ec)
      {
        std::size_t bytes = 0;
        handler_(ec, bytes);
        return;
      }

      // Commit received data to streambuf's get area.
      streambuf_.commit(bytes_transferred);

      // Determine the range of the data to be searched.
      typedef typename asio::basic_streambuf<
        Allocator>::const_buffers_type const_buffers_type;
      typedef asio::detail::const_buffers_iterator<
        const_buffers_type> iterator;
      const_buffers_type buffers = streambuf_.data();
      iterator begin(buffers, next_search_start_);
      iterator end(buffers, (std::numeric_limits<std::size_t>::max)());

      // Look for a match.
      std::pair<iterator, bool> result = asio::detail::partial_search(
          begin, end, delim_.begin(), delim_.end());
      if (result.first != end)
      {
        if (result.second)
        {
          // Full match. We're done.
          std::size_t bytes = result.first.position() + delim_.length();
          handler_(ec, bytes);
          return;
        }
        else
        {
          // Partial match. Next search needs to start from beginning of match.
          next_search_start_ = result.first.position();
        }
      }
      else
      {
        // No match. Next search can start with the new data.
        next_search_start_ = end.position();
      }

      // Check if buffer is full.
      if (streambuf_.size() == streambuf_.max_size())
      {
        std::size_t bytes = 0;
        asio::error_code ec(error::not_found);
        handler_(ec, bytes);
        return;
      }

      // Start a new asynchronous read operation to obtain more data.
      std::size_t bytes_available =
        std::min<std::size_t>(512, streambuf_.max_size() - streambuf_.size());
      stream_.async_read_some(streambuf_.prepare(bytes_available), *this);
    }

  //private:
    AsyncReadStream& stream_;
    asio::basic_streambuf<Allocator>& streambuf_;
    std::string delim_;
    std::size_t next_search_start_;
    ReadHandler handler_;
  };

  template <typename AsyncReadStream, typename Allocator, typename ReadHandler>
  inline void* asio_handler_allocate(std::size_t size,
      read_until_delim_string_handler<AsyncReadStream,
        Allocator, ReadHandler>* this_handler)
  {
    return asio_handler_alloc_helpers::allocate(
        size, &this_handler->handler_);
  }

  template <typename AsyncReadStream, typename Allocator, typename ReadHandler>
  inline void asio_handler_deallocate(void* pointer, std::size_t size,
      read_until_delim_string_handler<AsyncReadStream,
        Allocator, ReadHandler>* this_handler)
  {
    asio_handler_alloc_helpers::deallocate(
        pointer, size, &this_handler->handler_);
  }

  template <typename Function, typename AsyncReadStream,
      typename Allocator, typename ReadHandler>
  inline void asio_handler_invoke(const Function& function,
      read_until_delim_string_handler<AsyncReadStream,
        Allocator, ReadHandler>* this_handler)
  {
    asio_handler_invoke_helpers::invoke(
        function, &this_handler->handler_);
  }
} // namespace detail

template <typename AsyncReadStream, typename Allocator, typename ReadHandler>
void async_read_until(AsyncReadStream& s,
    asio::basic_streambuf<Allocator>& b, const std::string& delim,
    ReadHandler handler)
{
  // Determine the range of the data to be searched.
  typedef typename asio::basic_streambuf<
    Allocator>::const_buffers_type const_buffers_type;
  typedef asio::detail::const_buffers_iterator<
    const_buffers_type> iterator;
  const_buffers_type buffers = b.data();
  iterator begin(buffers, 0);
  iterator end(buffers, (std::numeric_limits<std::size_t>::max)());

  // Look for a match.
  std::size_t next_search_start;
  std::pair<iterator, bool> result = asio::detail::partial_search(
      begin, end, delim.begin(), delim.end());
  if (result.first != end)
  {
    if (result.second)
    {
      // Full match. We're done.
      asio::error_code ec;
      std::size_t bytes = result.first.position() + delim.length();
      s.io_service().post(detail::bind_handler(handler, ec, bytes));
      return;
    }
    else
    {
      // Partial match. Next search needs to start from beginning of match.
      next_search_start = result.first.position();
    }
  }
  else
  {
    // No match. Next search can start with the new data.
    next_search_start = end.position();
  }

  // Check if buffer is full.
  if (b.size() == b.max_size())
  {
    asio::error_code ec(error::not_found);
    s.io_service().post(detail::bind_handler(handler, ec, 0));
    return;
  }

  // Start a new asynchronous read operation to obtain more data.
  std::size_t bytes_available =
    std::min<std::size_t>(512, b.max_size() - b.size());
  s.async_read_some(b.prepare(bytes_available),
      detail::read_until_delim_string_handler<
        AsyncReadStream, Allocator, ReadHandler>(
          s, b, delim, next_search_start, handler));
}

namespace detail
{
  template <typename AsyncReadStream, typename Allocator, typename ReadHandler>
  class read_until_expr_handler
  {
  public:
    read_until_expr_handler(AsyncReadStream& stream,
        asio::basic_streambuf<Allocator>& streambuf,
        const boost::regex& expr, std::size_t next_search_start,
        ReadHandler handler)
      : stream_(stream),
        streambuf_(streambuf),
        expr_(expr),
        next_search_start_(next_search_start),
        handler_(handler)
    {
    }

    void operator()(const asio::error_code& ec,
        std::size_t bytes_transferred)
    {
      // Check for errors.
      if (ec)
      {
        std::size_t bytes = 0;
        handler_(ec, bytes);
        return;
      }

      // Commit received data to streambuf's get area.
      streambuf_.commit(bytes_transferred);

      // Determine the range of the data to be searched.
      typedef typename asio::basic_streambuf<
        Allocator>::const_buffers_type const_buffers_type;
      typedef asio::detail::const_buffers_iterator<
        const_buffers_type> iterator;
      const_buffers_type buffers = streambuf_.data();
      iterator begin(buffers, next_search_start_);
      iterator end(buffers, (std::numeric_limits<std::size_t>::max)());

      // Look for a match.
      boost::match_results<iterator> match_results;
      if (boost::regex_search(begin, end, match_results, expr_,
            boost::match_default | boost::match_partial))
      {
        if (match_results[0].matched)
        {
          // Full match. We're done.
          std::size_t bytes = match_results[0].second.position();
          handler_(ec, bytes);
          return;
        }
        else
        {
          // Partial match. Next search needs to start from beginning of match.
          next_search_start_ = match_results[0].first.position();
        }
      }
      else
      {
        // No match. Next search can start with the new data.
        next_search_start_ = end.position();
      }

      // Check if buffer is full.
      if (streambuf_.size() == streambuf_.max_size())
      {
        std::size_t bytes = 0;
        asio::error_code ec(error::not_found);
        handler_(ec, bytes);
        return;
      }

      // Start a new asynchronous read operation to obtain more data.
      std::size_t bytes_available =
        std::min<std::size_t>(512, streambuf_.max_size() - streambuf_.size());
      stream_.async_read_some(streambuf_.prepare(bytes_available), *this);
    }

  //private:
    AsyncReadStream& stream_;
    asio::basic_streambuf<Allocator>& streambuf_;
    boost::regex expr_;
    std::size_t next_search_start_;
    ReadHandler handler_;
  };

  template <typename AsyncReadStream, typename Allocator, typename ReadHandler>
  inline void* asio_handler_allocate(std::size_t size,
      read_until_expr_handler<AsyncReadStream,
        Allocator, ReadHandler>* this_handler)
  {
    return asio_handler_alloc_helpers::allocate(
        size, &this_handler->handler_);
  }

  template <typename AsyncReadStream, typename Allocator, typename ReadHandler>
  inline void asio_handler_deallocate(void* pointer, std::size_t size,
      read_until_expr_handler<AsyncReadStream,
        Allocator, ReadHandler>* this_handler)
  {
    asio_handler_alloc_helpers::deallocate(
        pointer, size, &this_handler->handler_);
  }

  template <typename Function, typename AsyncReadStream, typename Allocator,
      typename ReadHandler>
  inline void asio_handler_invoke(const Function& function,
      read_until_expr_handler<AsyncReadStream,
        Allocator, ReadHandler>* this_handler)
  {
    asio_handler_invoke_helpers::invoke(
        function, &this_handler->handler_);
  }
} // namespace detail

template <typename AsyncReadStream, typename Allocator, typename ReadHandler>
void async_read_until(AsyncReadStream& s,
    asio::basic_streambuf<Allocator>& b, const boost::regex& expr,
    ReadHandler handler)
{
  // Determine the range of the data to be searched.
  typedef typename asio::basic_streambuf<
    Allocator>::const_buffers_type const_buffers_type;
  typedef asio::detail::const_buffers_iterator<
    const_buffers_type> iterator;
  const_buffers_type buffers = b.data();
  iterator begin(buffers, 0);
  iterator end(buffers, (std::numeric_limits<std::size_t>::max)());

  // Look for a match.
  std::size_t next_search_start;
  boost::match_results<iterator> match_results;
  if (boost::regex_search(begin, end, match_results, expr,
        boost::match_default | boost::match_partial))
  {
    if (match_results[0].matched)
    {
      // Full match. We're done.
      asio::error_code ec;
      std::size_t bytes = match_results[0].second.position();
      s.io_service().post(detail::bind_handler(handler, ec, bytes));
      return;
    }
    else
    {
      // Partial match. Next search needs to start from beginning of match.
      next_search_start = match_results[0].first.position();
    }
  }
  else
  {
    // No match. Next search can start with the new data.
    next_search_start = end.position();
  }

  // Check if buffer is full.
  if (b.size() == b.max_size())
  {
    asio::error_code ec(error::not_found);
    s.io_service().post(detail::bind_handler(handler, ec, 0));
    return;
  }

  // Start a new asynchronous read operation to obtain more data.
  std::size_t bytes_available =
    std::min<std::size_t>(512, b.max_size() - b.size());
  s.async_read_some(b.prepare(bytes_available),
      detail::read_until_expr_handler<AsyncReadStream, Allocator, ReadHandler>(
        s, b, expr, next_search_start, handler));
}

} // namespace asio

#include "asio/detail/pop_options.hpp"

#endif // ASIO_READ_UNTIL_IPP