text: // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
  // (C) Copyright 2003-2007 Jonathan Turkanis
  // 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.)
  
  // See http://www.boost.org/libs/iostreams for documentation.
  
  #ifndef QSBOOST_IOSTREAMS_OPTIMAL_BUFFER_SIZE_HPP_INCLUDED
  #define QSBOOST_IOSTREAMS_OPTIMAL_BUFFER_SIZE_HPP_INCLUDED
  
  #if defined(_MSC_VER) && (_MSC_VER >= 1020)
  # pragma once
  #endif
  
  #include <qsboost/config.hpp>  // DEDUCED_TYPENAME, MSVC.
  #include <qsboost/detail/workaround.hpp>
  #include <qsboost/iostreams/constants.hpp>  // constants.
  #include <qsboost/iostreams/detail/dispatch.hpp>
  #include <qsboost/iostreams/detail/wrap_unwrap.hpp>
  #include <qsboost/iostreams/operations_fwd.hpp>
  #include <qsboost/mpl/if.hpp>
  
  // Must come last.
  #include <qsboost/iostreams/detail/config/disable_warnings.hpp>
  
  namespace qsboost { namespace iostreams {
  
  namespace detail {
  
  template<typename T>
  struct optimal_buffer_size_impl;
  
  } // End namespace detail.
  
  template<typename T>
  std::streamsize optimal_buffer_size(const T& t)
  {
      typedef detail::optimal_buffer_size_impl<T> impl;
      return impl::optimal_buffer_size(detail::unwrap(t));
  }
  
  namespace detail {
  
  //------------------Definition of optimal_buffer_size_impl--------------------//
  
  template<typename T>
  struct optimal_buffer_size_impl
      : mpl::if_<
            is_custom<T>,
            operations<T>,
            optimal_buffer_size_impl<
                QSBOOST_DEDUCED_TYPENAME
                dispatch<
                    T, optimally_buffered_tag, device_tag, filter_tag
                >::type
            >
        >::type
      { };
  
  template<>
  struct optimal_buffer_size_impl<optimally_buffered_tag> {
      template<typename T>
      static std::streamsize optimal_buffer_size(const T& t)
      { return t.optimal_buffer_size(); }
  };
  
  template<>
  struct optimal_buffer_size_impl<device_tag> {
      template<typename T>
      static std::streamsize optimal_buffer_size(const T&)
      { return default_device_buffer_size; }
  };
  
  template<>
  struct optimal_buffer_size_impl<filter_tag> {
      template<typename T>
      static std::streamsize optimal_buffer_size(const T&)
      { return default_filter_buffer_size; }
  };
  
  } // End namespace detail.
  
  } } // End namespaces iostreams, boost.
  
  #include <qsboost/iostreams/detail/config/enable_warnings.hpp>
  
  #endif // #ifndef BOOST_IOSTREAMS_OPTIMAL_BUFFER_SIZE_HPP_INCLUDED
  