text: //
  // detail/buffer_resize_guard.hpp
  // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  //
  // Copyright (c) 2003-2022 Christopher M. Kohlhoff (chris at kohlhoff dot com)
  //
  // Distributed under the Boost Software License, Version 1.0. (See accompanying
  // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  //
  
  #ifndef BOOST_ASIO_DETAIL_BUFFER_RESIZE_GUARD_HPP
  #define BOOST_ASIO_DETAIL_BUFFER_RESIZE_GUARD_HPP
  
  #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  # pragma once
  #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  
  #include <boost/asio/detail/config.hpp>
  #include <boost/asio/detail/limits.hpp>
  
  #include <boost/asio/detail/push_options.hpp>
  
  namespace boost {
  namespace asio {
  namespace detail {
  
  // Helper class to manage buffer resizing in an exception safe way.
  template <typename Buffer>
  class buffer_resize_guard
  {
  public:
    // Constructor.
    buffer_resize_guard(Buffer& buffer)
      : buffer_(buffer),
        old_size_(buffer.size())
    {
    }
  
    // Destructor rolls back the buffer resize unless commit was called.
    ~buffer_resize_guard()
    {
      if (old_size_ != (std::numeric_limits<size_t>::max)())
      {
        buffer_.resize(old_size_);
      }
    }
  
    // Commit the resize transaction.
    void commit()
    {
      old_size_ = (std::numeric_limits<size_t>::max)();
    }
  
  private:
    // The buffer being managed.
    Buffer& buffer_;
  
    // The size of the buffer at the time the guard was constructed.
    size_t old_size_;
  };
  
  } // namespace detail
  } // namespace asio
  } // namespace boost
  
  #include <boost/asio/detail/pop_options.hpp>
  
  #endif // BOOST_ASIO_DETAIL_BUFFER_RESIZE_GUARD_HPP
  