ceph/src/boost/boost/iostreams/detail/adapter/non_blocking_adapter.hpp

   1 // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
   2 // (C) Copyright 2005-2007 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_NON_BLOCKING_ADAPTER_HPP_INCLUDED
   9 #define BOOST_IOSTREAMS_DETAIL_NON_BLOCKING_ADAPTER_HPP_INCLUDED
  10
  11 #include <boost/iostreams/detail/ios.hpp>  // streamsize, seekdir, openmode.
  12 #include <boost/iostreams/read.hpp>
  13 #include <boost/iostreams/seek.hpp>
  14 #include <boost/iostreams/traits.hpp>
  15 #include <boost/iostreams/write.hpp>
  16
  17 namespace boost { namespace iostreams {
  18
  19 template<typename Device>
  20 class non_blocking_adapter {
  21 public:
  22     typedef typename char_type_of<Device>::type char_type;
  23     struct category
  24         : mode_of<Device>::type, device_tag
  25         { };
  26     explicit non_blocking_adapter(Device& dev) : device_(dev) { }
  27     std::streamsize read(char_type* s, std::streamsize n)
  28     {
  29         std::streamsize result = 0;
  30         while (result < n) {
  31             std::streamsize amt = iostreams::read(device_, s + result, n - result);
  32             if (amt == -1)
  33                 break;
  34             result += amt;
  35         }
  36         return result != 0 ? result : -1;
  37     }
  38     std::streamsize write(const char_type* s, std::streamsize n)
  39     {
  40         std::streamsize result = 0;
  41         while (result < n) {
  42             std::streamsize amt =
  43                 iostreams::write(device_, s + result, n - result);
  44             // write errors, like EOF on read, need to be handled.
  45             if (amt == -1)
  46                 break;
  47             result += amt;
  48         }
  49         return result;
  50     }
  51     std::streampos seek( stream_offset off, BOOST_IOS::seekdir way,
  52                          BOOST_IOS::openmode which =
  53                              BOOST_IOS::in | BOOST_IOS::out )
  54     { return iostreams::seek(device_, off, way, which); }
  55 public:
  56     non_blocking_adapter& operator=(const non_blocking_adapter&);
  57     Device& device_;
  58 };
  59
  60 } } // End namespace iostreams.
  61
  62 #endif // #ifndef BOOST_IOSTREAMS_DETAIL_NON_BLOCKING_ADAPTER_HPP_INCLUDED