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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)
12 # pragma once
13 #endif
14 
15 #include <boost/config.hpp>                        // member template friends.
16 #include <boost/core/typeinfo.hpp>
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:
linked_streambuf()43     linked_streambuf() : flags_(0) { }
set_true_eof(bool eof)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.
true_eof() const52     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
close(BOOST_IOS::openmode which)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     }
set_needs_close()85     void set_needs_close()
86     {
87         flags_ &= ~(f_input_closed | f_output_closed);
88     }
set_next(linked_streambuf<Ch,Tr> *)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 boost::core::typeinfo& 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
115