boost/boost/iostreams/stream_buffer.hpp

   1 // (C) Copyright Jonathan Turkanis 2003.
   2 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   3 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)
   4
   5 // See http://www.boost.org/libs/iostreams for documentation.
   6
   7 #ifndef BOOST_IOSTREAMS_STREAM_BUFFER_HPP_INCLUDED
   8 #define BOOST_IOSTREAMS_STREAM_BUFFER_HPP_INCLUDED
   9
  10 #if defined(_MSC_VER) && (_MSC_VER >= 1020)
  11 # pragma once
  12 #endif
  13
  14 #include <memory>            // allocator.
  15 #include <boost/config.hpp>  // BOOST_DEDUCED_TYPENAME.
  16 #include <boost/iostreams/detail/char_traits.hpp>
  17 #include <boost/iostreams/detail/config/overload_resolution.hpp>
  18 #include <boost/iostreams/detail/forward.hpp>
  19 #include <boost/iostreams/detail/ios.hpp>  // failure, streamsize.
  20 #include <boost/iostreams/detail/streambuf/direct_streambuf.hpp>
  21 #include <boost/iostreams/detail/streambuf/indirect_streambuf.hpp>
  22 #include <boost/iostreams/traits.hpp>
  23 #include <boost/static_assert.hpp>
  24 #include <boost/type_traits/is_convertible.hpp>
  25
  26 // Must come last.
  27 #include <boost/iostreams/detail/config/disable_warnings.hpp>  // MSVC.
  28
  29 namespace boost { namespace iostreams { namespace detail {
  30
  31 template<typename T, typename Tr, typename Alloc, typename Mode>
  32 struct stream_buffer_traits {
  33     typedef typename
  34             mpl::if_<
  35                 is_convertible<
  36                     BOOST_DEDUCED_TYPENAME category_of<T>::type,
  37                     direct_tag
  38                 >,
  39                 direct_streambuf<T, Tr>,
  40                 indirect_streambuf<T, Tr, Alloc, Mode>
  41             >::type type;
  42 };
  43
  44 } } } // End namespaces detail, iostreams, boost
  45
  46 #ifdef BOOST_IOSTREAMS_BROKEN_OVERLOAD_RESOLUTION
  47 # include <boost/iostreams/detail/broken_overload_resolution/stream_buffer.hpp>
  48 #else
  49
  50 namespace boost { namespace iostreams {
  51
  52 template< typename T,
  53           typename Tr =
  54               BOOST_IOSTREAMS_CHAR_TRAITS(
  55                   BOOST_DEDUCED_TYPENAME char_type_of<T>::type
  56               ),
  57           typename Alloc =
  58               std::allocator<
  59                   BOOST_DEDUCED_TYPENAME char_type_of<T>::type
  60               >,
  61           typename Mode = BOOST_DEDUCED_TYPENAME mode_of<T>::type >
  62 class stream_buffer
  63     : public detail::stream_buffer_traits<T, Tr, Alloc, Mode>::type
  64 {
  65 private:
  66     BOOST_STATIC_ASSERT((
  67         is_convertible<
  68             BOOST_DEDUCED_TYPENAME iostreams::category_of<T>::type, Mode
  69         >::value
  70     ));
  71     typedef typename
  72             detail::stream_buffer_traits<
  73                 T, Tr, Alloc, Mode
  74             >::type                           base_type;
  75     typedef T                                 policy_type;
  76 public:
  77     typedef typename char_type_of<T>::type    char_type;
  78     BOOST_IOSTREAMS_STREAMBUF_TYPEDEFS(Tr)
  79 public:
  80     stream_buffer() { }
  81     ~stream_buffer()
  82     {
  83         try {
  84             if (this->is_open() && this->auto_close())
  85                 this->close();
  86         } catch (std::exception&) { }
  87     }
  88     BOOST_IOSTREAMS_FORWARD( stream_buffer, open_impl, T,
  89                              BOOST_IOSTREAMS_PUSH_PARAMS,
  90                              BOOST_IOSTREAMS_PUSH_ARGS )
  91     T& operator*() { return *this->component(); }
  92     T* operator->() { return this->component(); }
  93 private:
  94     void open_impl(const T& t BOOST_IOSTREAMS_PUSH_PARAMS())
  95         {   // Used for forwarding.
  96             if (this->is_open())
  97                 BOOST_IOSTREAMS_FAILURE("already open");
  98             base_type::open(t BOOST_IOSTREAMS_PUSH_ARGS());
  99         }
 100 };
 101
 102 } } // End namespaces iostreams, boost.
 103
 104 #endif // #ifdef BOOST_IOSTREAMS_BROKEN_OVERLOAD_RESOLUTION
 105
 106 #include <boost/iostreams/detail/config/enable_warnings.hpp>  // MSVC.
 107
 108 #endif // #ifndef BOOST_IOSTREAMS_STREAM_BUFFER_HPP_INCLUDED