boost/iostreams/detail/streambuf/linked_streambuf.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_DETAIL_LINKED_STREAMBUF_HPP_INCLUDED
   9 #define BOOST_IOSTREAMS_DETAIL_LINKED_STREAMBUF_HPP_INCLUDED
  10
  11 #if defined(_MSC_VER) && (_MSC_VER >= 1020)
  12 # pragma once
  13 #endif
  14
  15 #include <typeinfo>
  16 #include <boost/config.hpp>                        // member template friends.
  17 #include <boost/iostreams/detail/char_traits.hpp>
  18 #include <boost/iostreams/detail/ios.hpp>          // openmode.
  19 #include <boost/iostreams/detail/streambuf.hpp>
  20
  21 // Must come last.
  22 #include <boost/iostreams/detail/config/disable_warnings.hpp> // MSVC.
  23
  24 namespace boost { namespace iostreams { namespace detail {
  25
  26 template<typename Self, typename Ch, typename Tr, typename Alloc, typename Mode>
  27 class chain_base;
  28
  29 template<typename Chain, typename Access, typename Mode> class chainbuf;
  30
  31 #define BOOST_IOSTREAMS_USING_PROTECTED_STREAMBUF_MEMBERS(base) \
  32     using base::eback; using base::gptr; using base::egptr; \
  33     using base::setg; using base::gbump; using base::pbase; \
  34     using base::pptr; using base::epptr; using base::setp; \
  35     using base::pbump; using base::underflow; using base::pbackfail; \
  36     using base::xsgetn; using base::overflow; using base::xsputn; \
  37     using base::sync; using base::seekoff; using base::seekpos; \
  38     /**/
  39
  40 template<typename Ch, typename Tr = BOOST_IOSTREAMS_CHAR_TRAITS(Ch) >
  41 class linked_streambuf : public BOOST_IOSTREAMS_BASIC_STREAMBUF(Ch, Tr) {
  42 protected:
  43     linked_streambuf() : flags_(0) { }
  44     void set_true_eof(bool eof)
  45     {
  46         flags_ = (flags_ & ~f_true_eof) | (eof ? f_true_eof : 0);
  47     }
  48 public:
  49
  50     // Should be called only after receiving an ordinary EOF indication,
  51     // to confirm that it represents EOF rather than WOULD_BLOCK.
  52     bool true_eof() const { return (flags_ & f_true_eof) != 0; }
  53 protected:
  54
  55     //----------grant friendship to chain_base and chainbuf-------------------//
  56
  57 #ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
  58     template< typename Self, typename ChT, typename TrT,
  59               typename Alloc, typename Mode >
  60     friend class chain_base;
  61     template<typename Chain, typename Mode, typename Access>
  62     friend class chainbuf;
  63     template<typename U>
  64     friend class member_close_operation;
  65 #else
  66     public:
  67         typedef BOOST_IOSTREAMS_BASIC_STREAMBUF(Ch, Tr) base;
  68         BOOST_IOSTREAMS_USING_PROTECTED_STREAMBUF_MEMBERS(base)
  69 #endif
  70     void close(BOOST_IOS::openmode which)
  71     {
  72         if ( which == BOOST_IOS::in &&
  73             (flags_ & f_input_closed) == 0 )
  74         {
  75             flags_ |= f_input_closed;
  76             close_impl(which);
  77         }
  78         if ( which == BOOST_IOS::out &&
  79             (flags_ & f_output_closed) == 0 )
  80         {
  81             flags_ |= f_output_closed;
  82             close_impl(which);
  83         }
  84     }
  85     void set_needs_close()
  86     {
  87         flags_ &= ~(f_input_closed | f_output_closed);
  88     }
  89     virtual void set_next(linked_streambuf<Ch, Tr>* /* next */) { }
  90     virtual void close_impl(BOOST_IOS::openmode) = 0;
  91     virtual bool auto_close() const = 0;
  92     virtual void set_auto_close(bool) = 0;
  93     virtual bool strict_sync() = 0;
  94     virtual const std::type_info& component_type() const = 0;
  95     virtual void* component_impl() = 0;
  96 #ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS
  97     private:
  98 #else
  99     public:
 100 #endif
 101 private:
 102     enum flag_type {
 103         f_true_eof       = 1,
 104         f_input_closed   = f_true_eof << 1,
 105         f_output_closed  = f_input_closed << 1
 106     };
 107     int flags_;
 108 };
 109
 110 } } } // End namespaces detail, iostreams, boost.
 111
 112 #include <boost/iostreams/detail/config/enable_warnings.hpp> // MSVC.
 113
 114 #endif // #ifndef BOOST_IOSTREAMS_DETAIL_LINKED_STREAMBUF_HPP_INCLUDED