detail/streambuf/linked_streambuf.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_DETAIL_LINKED_STREAMBUF_HPP_INCLUDED
0009 #define BOOST_IOSTREAMS_DETAIL_LINKED_STREAMBUF_HPP_INCLUDED
0010
0011 #if defined(_MSC_VER)
0012 # pragma once
0013 #endif
0014
0015 #include <boost/config.hpp>                        // member template friends.
0016 #include <boost/core/typeinfo.hpp>
0017 #include <boost/iostreams/detail/char_traits.hpp>
0018 #include <boost/iostreams/detail/ios.hpp>          // openmode.
0019 #include <boost/iostreams/detail/streambuf.hpp>
0020
0021 // Must come last.
0022 #include <boost/iostreams/detail/config/disable_warnings.hpp> // MSVC.
0023
0024 namespace boost { namespace iostreams { namespace detail {
0025
0026 template<typename Self, typename Ch, typename Tr, typename Alloc, typename Mode>
0027 class chain_base;
0028
0029 template<typename Chain, typename Access, typename Mode> class chainbuf;
0030
0031 #define BOOST_IOSTREAMS_USING_PROTECTED_STREAMBUF_MEMBERS(base) \
0032     using base::eback; using base::gptr; using base::egptr; \
0033     using base::setg; using base::gbump; using base::pbase; \
0034     using base::pptr; using base::epptr; using base::setp; \
0035     using base::pbump; using base::underflow; using base::pbackfail; \
0036     using base::xsgetn; using base::overflow; using base::xsputn; \
0037     using base::sync; using base::seekoff; using base::seekpos; \
0038     /**/
0039
0040 template<typename Ch, typename Tr = BOOST_IOSTREAMS_CHAR_TRAITS(Ch) >
0041 class linked_streambuf : public BOOST_IOSTREAMS_BASIC_STREAMBUF(Ch, Tr) {
0042 protected:
0043     linked_streambuf() : flags_(0) { }
0044     void set_true_eof(bool eof)
0045     {
0046         flags_ = (flags_ & ~f_true_eof) | (eof ? f_true_eof : 0);
0047     }
0048 public:
0049
0050     // Should be called only after receiving an ordinary EOF indication,
0051     // to confirm that it represents EOF rather than WOULD_BLOCK.
0052     bool true_eof() const { return (flags_ & f_true_eof) != 0; }
0053 protected:
0054
0055     //----------grant friendship to chain_base and chainbuf-------------------//
0056
0057 #ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
0058     template< typename Self, typename ChT, typename TrT,
0059               typename Alloc, typename Mode >
0060     friend class chain_base;
0061     template<typename Chain, typename Mode, typename Access>
0062     friend class chainbuf;
0063     template<typename U>
0064     friend class member_close_operation;
0065 #else
0066     public:
0067         typedef BOOST_IOSTREAMS_BASIC_STREAMBUF(Ch, Tr) base;
0068         BOOST_IOSTREAMS_USING_PROTECTED_STREAMBUF_MEMBERS(base)
0069 #endif
0070     void close(BOOST_IOS::openmode which)
0071     {
0072         if ( which == BOOST_IOS::in &&
0073             (flags_ & f_input_closed) == 0 )
0074         {
0075             flags_ |= f_input_closed;
0076             close_impl(which);
0077         }
0078         if ( which == BOOST_IOS::out &&
0079             (flags_ & f_output_closed) == 0 )
0080         {
0081             flags_ |= f_output_closed;
0082             close_impl(which);
0083         }
0084     }
0085     void set_needs_close()
0086     {
0087         flags_ &= ~(f_input_closed | f_output_closed);
0088     }
0089     virtual void set_next(linked_streambuf<Ch, Tr>* /* next */) { }
0090     virtual void close_impl(BOOST_IOS::openmode) = 0;
0091     virtual bool auto_close() const = 0;
0092     virtual void set_auto_close(bool) = 0;
0093     virtual bool strict_sync() = 0;
0094     virtual const boost::core::typeinfo& component_type() const = 0;
0095     virtual void* component_impl() = 0;
0096 #ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
0097     private:
0098 #else
0099     public:
0100 #endif
0101 private:
0102     enum flag_type {
0103         f_true_eof       = 1,
0104         f_input_closed   = f_true_eof << 1,
0105         f_output_closed  = f_input_closed << 1
0106     };
0107     int flags_;
0108 };
0109
0110 } } } // End namespaces detail, iostreams, boost.
0111
0112 #include <boost/iostreams/detail/config/enable_warnings.hpp> // MSVC.
0113
0114 #endif // #ifndef BOOST_IOSTREAMS_DETAIL_LINKED_STREAMBUF_HPP_INCLUDED