ceph/src/boost/libs/iostreams/include/boost/iostreams/detail/streambuf/chainbuf.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_CHAINBUF_HPP_INCLUDED
   9 #define BOOST_IOSTREAMS_DETAIL_CHAINBUF_HPP_INCLUDED
  10
  11 #if defined(_MSC_VER)
  12 # pragma once
  13 #endif
  14
  15 #include <boost/config.hpp>                    // BOOST_MSVC, template friends.
  16 #include <boost/detail/workaround.hpp>
  17 #include <boost/iostreams/chain.hpp>
  18 #include <boost/iostreams/detail/access_control.hpp>
  19 #include <boost/iostreams/detail/config/wide_streams.hpp>
  20 #include <boost/iostreams/detail/streambuf.hpp>
  21 #include <boost/iostreams/detail/streambuf/linked_streambuf.hpp>
  22 #include <boost/iostreams/detail/translate_int_type.hpp>
  23 #include <boost/iostreams/traits.hpp>
  24 #include <boost/noncopyable.hpp>
  25
  26 namespace boost { namespace iostreams { namespace detail {
  27
  28 //--------------Definition of chainbuf----------------------------------------//
  29
  30 //
  31 // Template name: chainbuf.
  32 // Description: Stream buffer which operates by delegating to the first
  33 //      linked_streambuf in a chain.
  34 // Template parameters:
  35 //      Chain - The chain type.
  36 //
  37 template<typename Chain, typename Mode, typename Access>
  38 class chainbuf
  39     : public BOOST_IOSTREAMS_BASIC_STREAMBUF(
  40                  typename Chain::char_type,
  41                  typename Chain::traits_type
  42              ),
  43       public access_control<typename Chain::client_type, Access>,
  44       private noncopyable
  45 {
  46 private:
  47     typedef access_control<chain_client<Chain>, Access>      client_type;
  48 public:
  49     typedef typename Chain::char_type                        char_type;
  50     BOOST_IOSTREAMS_STREAMBUF_TYPEDEFS(typename Chain::traits_type)
  51 protected:
  52     typedef linked_streambuf<char_type, traits_type>         delegate_type;
  53     chainbuf() { client_type::set_chain(&chain_); }
  54     int_type underflow()
  55         { sentry t(this); return translate(delegate().underflow()); }
  56     int_type pbackfail(int_type c)
  57         { sentry t(this); return translate(delegate().pbackfail(c)); }
  58     std::streamsize xsgetn(char_type* s, std::streamsize n)
  59         { sentry t(this); return delegate().xsgetn(s, n); }
  60     int_type overflow(int_type c)
  61         { sentry t(this); return translate(delegate().overflow(c)); }
  62     std::streamsize xsputn(const char_type* s, std::streamsize n)
  63         { sentry t(this); return delegate().xsputn(s, n); }
  64     int sync() { sentry t(this); return delegate().sync(); }
  65     pos_type seekoff( off_type off, BOOST_IOS::seekdir way,
  66                       BOOST_IOS::openmode which =
  67                           BOOST_IOS::in | BOOST_IOS::out )
  68         { sentry t(this); return delegate().seekoff(off, way, which); }
  69     pos_type seekpos( pos_type sp,
  70                       BOOST_IOS::openmode which =
  71                           BOOST_IOS::in | BOOST_IOS::out )
  72         { sentry t(this); return delegate().seekpos(sp, which); }
  73 protected:
  74     typedef BOOST_IOSTREAMS_BASIC_STREAMBUF(
  75                  typename Chain::char_type,
  76                  typename Chain::traits_type
  77              )                                               base_type;
  78 private:
  79
  80     // Translate from std int_type to chain's int_type.
  81     typedef BOOST_IOSTREAMS_CHAR_TRAITS(char_type)           std_traits;
  82     typedef typename Chain::traits_type                      chain_traits;
  83     static typename chain_traits::int_type
  84     translate(typename std_traits::int_type c)
  85         { return translate_int_type<std_traits, chain_traits>(c); }
  86
  87     delegate_type& delegate()
  88         { return static_cast<delegate_type&>(chain_.front()); }
  89     void get_pointers()
  90         {
  91             this->setg(delegate().eback(), delegate().gptr(), delegate().egptr());
  92             this->setp(delegate().pbase(), delegate().epptr());
  93             this->pbump((int) (delegate().pptr() - delegate().pbase()));
  94         }
  95     void set_pointers()
  96         {
  97             delegate().setg(this->eback(), this->gptr(), this->egptr());
  98             delegate().setp(this->pbase(), this->epptr());
  99             delegate().pbump((int) (this->pptr() - this->pbase()));
 100         }
 101     struct sentry {
 102         sentry(chainbuf<Chain, Mode, Access>* buf) : buf_(buf)
 103             { buf_->set_pointers(); }
 104         ~sentry() { buf_->get_pointers(); }
 105         chainbuf<Chain, Mode, Access>* buf_;
 106     };
 107     friend struct sentry;
 108     Chain chain_;
 109 };
 110
 111 } } } // End namespaces detail, iostreams, boost.
 112
 113 #endif // #ifndef BOOST_IOSTREAMS_DETAIL_CHAINBUF_HPP_INCLUDED