boost/iostreams/stream_buffer.hpp

0001 // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
0002 // (C) Copyright 2003-2007 Jonathan Turkanis
0003 // Distributed under the Boost Software License, Version 1.0. (See accompanying
0004 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)
0005
0006 // See http://www.boost.org/libs/iostreams for documentation.
0007
0008 #ifndef BOOST_IOSTREAMS_STREAM_BUFFER_HPP_INCLUDED
0009 #define BOOST_IOSTREAMS_STREAM_BUFFER_HPP_INCLUDED
0010
0011 #if defined(_MSC_VER)
0012 # pragma once
0013 #endif
0014
0015 #include <memory>            // allocator.
0016 #include <boost/config.hpp>  // BOOST_DEDUCED_TYPENAME.
0017 #include <boost/iostreams/detail/char_traits.hpp>
0018 #include <boost/iostreams/detail/config/overload_resolution.hpp>
0019 #include <boost/iostreams/detail/forward.hpp>
0020 #include <boost/iostreams/detail/ios.hpp>  // failure, streamsize.
0021 #include <boost/iostreams/detail/streambuf/direct_streambuf.hpp>
0022 #include <boost/iostreams/detail/streambuf/indirect_streambuf.hpp>
0023 #include <boost/iostreams/traits.hpp>
0024 #include <boost/static_assert.hpp>
0025 #include <boost/throw_exception.hpp>
0026 #include <boost/type_traits/is_convertible.hpp>
0027
0028 // Must come last.
0029 #include <boost/iostreams/detail/config/disable_warnings.hpp>  // MSVC.
0030
0031 namespace boost { namespace iostreams { namespace detail {
0032
0033 template<typename T, typename Tr, typename Alloc, typename Mode>
0034 struct stream_buffer_traits {
0035     typedef typename
0036             mpl::if_<
0037                 is_convertible<
0038                     BOOST_DEDUCED_TYPENAME category_of<T>::type,
0039                     direct_tag
0040                 >,
0041                 direct_streambuf<T, Tr>,
0042                 indirect_streambuf<T, Tr, Alloc, Mode>
0043             >::type type;
0044 };
0045
0046 } } } // End namespaces detail, iostreams, boost
0047
0048 #ifdef BOOST_IOSTREAMS_BROKEN_OVERLOAD_RESOLUTION
0049 # include <boost/iostreams/detail/broken_overload_resolution/stream_buffer.hpp>
0050 #else
0051
0052 namespace boost { namespace iostreams {
0053
0054 template< typename T,
0055           typename Tr =
0056               BOOST_IOSTREAMS_CHAR_TRAITS(
0057                   BOOST_DEDUCED_TYPENAME char_type_of<T>::type
0058               ),
0059           typename Alloc =
0060               std::allocator<
0061                   BOOST_DEDUCED_TYPENAME char_type_of<T>::type
0062               >,
0063           typename Mode = BOOST_DEDUCED_TYPENAME mode_of<T>::type >
0064 class stream_buffer
0065     : public detail::stream_buffer_traits<T, Tr, Alloc, Mode>::type
0066 {
0067 private:
0068     BOOST_STATIC_ASSERT((
0069         is_convertible<
0070             BOOST_DEDUCED_TYPENAME iostreams::category_of<T>::type, Mode
0071         >::value
0072     ));
0073     typedef typename
0074             detail::stream_buffer_traits<
0075                 T, Tr, Alloc, Mode
0076             >::type                           base_type;
0077 public:
0078     typedef typename char_type_of<T>::type    char_type;
0079     struct category
0080         : Mode,
0081           closable_tag,
0082           streambuf_tag
0083         { };
0084     BOOST_IOSTREAMS_STREAMBUF_TYPEDEFS(Tr)
0085 public:
0086     stream_buffer() { }
0087     ~stream_buffer()
0088     {
0089         try {
0090             if (this->is_open() && this->auto_close())
0091                 this->close();
0092         } catch (...) { }
0093     }
0094     BOOST_IOSTREAMS_FORWARD( stream_buffer, open_impl, T,
0095                              BOOST_IOSTREAMS_PUSH_PARAMS,
0096                              BOOST_IOSTREAMS_PUSH_ARGS )
0097     T& operator*() { return *this->component(); }
0098     T* operator->() { return this->component(); }
0099 private:
0100     void open_impl(const T& t BOOST_IOSTREAMS_PUSH_PARAMS())
0101         {   // Used for forwarding.
0102             if (this->is_open())
0103                 boost::throw_exception(
0104                     BOOST_IOSTREAMS_FAILURE("already open")
0105                 );
0106             base_type::open(t BOOST_IOSTREAMS_PUSH_ARGS());
0107         }
0108 };
0109
0110 } } // End namespaces iostreams, boost.
0111
0112 #endif // #ifdef BOOST_IOSTREAMS_BROKEN_OVERLOAD_RESOLUTION
0113
0114 #include <boost/iostreams/detail/config/enable_warnings.hpp>  // MSVC.
0115
0116 #endif // #ifndef BOOST_IOSTREAMS_STREAM_BUFFER_HPP_INCLUDED