boost/iostreams/stream_buffer.hpp

   1 // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
   2 // (C) Copyright 2003-2007 Jonathan Turkanis
   3 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   4 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)
   5
   6 // See http://www.boost.org/libs/iostreams for documentation.
   7
   8 #ifndef BOOST_IOSTREAMS_STREAM_BUFFER_HPP_INCLUDED
   9 #define BOOST_IOSTREAMS_STREAM_BUFFER_HPP_INCLUDED
  10
  11 #if defined(_MSC_VER) && (_MSC_VER >= 1020)
  12 # pragma once
  13 #endif
  14
  15 #include <memory>            // allocator.
  16 #include <boost/config.hpp>  // BOOST_DEDUCED_TYPENAME.
  17 #include <boost/iostreams/detail/char_traits.hpp>
  18 #include <boost/iostreams/detail/config/overload_resolution.hpp>
  19 #include <boost/iostreams/detail/forward.hpp>
  20 #include <boost/iostreams/detail/ios.hpp>  // failure, streamsize.
  21 #include <boost/iostreams/detail/streambuf/direct_streambuf.hpp>
  22 #include <boost/iostreams/detail/streambuf/indirect_streambuf.hpp>
  23 #include <boost/iostreams/traits.hpp>
  24 #include <boost/static_assert.hpp>
  25 #include <boost/type_traits/is_convertible.hpp>
  26
  27 // Must come last.
  28 #include <boost/iostreams/detail/config/disable_warnings.hpp>  // MSVC.
  29
  30 namespace boost { namespace iostreams { namespace detail {
  31
  32 template<typename T, typename Tr, typename Alloc, typename Mode>
  33 struct stream_buffer_traits {
  34     typedef typename
  35             mpl::if_<
  36                 is_convertible<
  37                     BOOST_DEDUCED_TYPENAME category_of<T>::type,
  38                     direct_tag
  39                 >,
  40                 direct_streambuf<T, Tr>,
  41                 indirect_streambuf<T, Tr, Alloc, Mode>
  42             >::type type;
  43 };
  44
  45 } } } // End namespaces detail, iostreams, boost
  46
  47 #ifdef BOOST_IOSTREAMS_BROKEN_OVERLOAD_RESOLUTION
  48 # include <boost/iostreams/detail/broken_overload_resolution/stream_buffer.hpp>
  49 #else
  50
  51 namespace boost { namespace iostreams {
  52
  53 template< typename T,
  54           typename Tr =
  55               BOOST_IOSTREAMS_CHAR_TRAITS(
  56                   BOOST_DEDUCED_TYPENAME char_type_of<T>::type
  57               ),
  58           typename Alloc =
  59               std::allocator<
  60                   BOOST_DEDUCED_TYPENAME char_type_of<T>::type
  61               >,
  62           typename Mode = BOOST_DEDUCED_TYPENAME mode_of<T>::type >
  63 class stream_buffer
  64     : public detail::stream_buffer_traits<T, Tr, Alloc, Mode>::type
  65 {
  66 private:
  67     BOOST_STATIC_ASSERT((
  68         is_convertible<
  69             BOOST_DEDUCED_TYPENAME iostreams::category_of<T>::type, Mode
  70         >::value
  71     ));
  72     typedef typename
  73             detail::stream_buffer_traits<
  74                 T, Tr, Alloc, Mode
  75             >::type                           base_type;
  76 public:
  77     typedef typename char_type_of<T>::type    char_type;
  78     struct category
  79         : Mode,
  80           closable_tag,
  81           streambuf_tag
  82         { };
  83     BOOST_IOSTREAMS_STREAMBUF_TYPEDEFS(Tr)
  84 public:
  85     stream_buffer() { }
  86     ~stream_buffer()
  87     {
  88         try {
  89             if (this->is_open() && this->auto_close())
  90                 this->close();
  91         } catch (...) { }
  92     }
  93     BOOST_IOSTREAMS_FORWARD( stream_buffer, open_impl, T,
  94                              BOOST_IOSTREAMS_PUSH_PARAMS,
  95                              BOOST_IOSTREAMS_PUSH_ARGS )
  96     T& operator*() { return *this->component(); }
  97     T* operator->() { return this->component(); }
  98 private:
  99     void open_impl(const T& t BOOST_IOSTREAMS_PUSH_PARAMS())
 100         {   // Used for forwarding.
 101             if (this->is_open())
 102                 BOOST_IOSTREAMS_FAILURE("already open");
 103             base_type::open(t BOOST_IOSTREAMS_PUSH_ARGS());
 104         }
 105 };
 106
 107 } } // End namespaces iostreams, boost.
 108
 109 #endif // #ifdef BOOST_IOSTREAMS_BROKEN_OVERLOAD_RESOLUTION
 110
 111 #include <boost/iostreams/detail/config/enable_warnings.hpp>  // MSVC.
 112
 113 #endif // #ifndef BOOST_IOSTREAMS_STREAM_BUFFER_HPP_INCLUDED