boost/boost/iostreams/positioning.hpp

   1 // (C) Copyright Jonathan Turkanis 2003.
   2 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   3 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)
   4
   5 // See http://www.boost.org/libs/iostreams for documentation.
   6
   7 // Thanks to Gareth Sylvester-Bradley for the Dinkumware versions of the
   8 // positioning functions.
   9
  10 #ifndef BOOST_IOSTREAMS_POSITIONING_HPP_INCLUDED
  11 #define BOOST_IOSTREAMS_POSITIONING_HPP_INCLUDED
  12
  13 #if defined(_MSC_VER) && (_MSC_VER >= 1020)
  14 # pragma once
  15 #endif
  16
  17 #include <boost/cstdint.hpp>
  18 #include <boost/integer_traits.hpp>
  19 #include <boost/iostreams/detail/config/codecvt.hpp> // mbstate_t.
  20 #include <boost/iostreams/detail/ios.hpp> // streamoff, streampos.
  21
  22 // Must come last.
  23 #include <boost/iostreams/detail/config/disable_warnings.hpp>
  24
  25 namespace boost { namespace iostreams {
  26
  27 typedef boost::intmax_t stream_offset;
  28
  29 inline std::streamoff stream_offset_to_streamoff(stream_offset off)
  30 { return static_cast<stream_offset>(off); }
  31
  32 template<typename PosType> // Hande custom pos_type's.
  33 inline stream_offset position_to_offset(PosType pos)
  34 { return std::streamoff(pos); }
  35
  36 #if ((defined(_YVALS) && !defined(__IBMCPP__)) || defined(_CPPLIB_VER)) && \
  37      !defined(__SGI_STL_PORT) && !defined(_STLPORT_VERSION) \
  38      && !defined(__QNX__) \
  39    /**/
  40
  41         /* Dinkumware */
  42
  43 inline std::streampos offset_to_position(stream_offset off)
  44 {
  45     // Use implementation-specific constructor.
  46     return std::streampos(std::mbstate_t(), off);
  47 }
  48
  49 inline stream_offset fpos_t_to_offset(fpos_t pos)
  50 { // Helper function.
  51 #if defined(_POSIX_) || (_INTEGRAL_MAX_BITS >= 64)
  52     return pos;
  53 #else
  54     return _FPOSOFF(pos);
  55 #endif
  56 }
  57
  58 # if defined(_CPPLIB_VER) //--------------------------------------------------//
  59
  60         /* Recent Dinkumware */
  61
  62 inline stream_offset position_to_offset(std::streampos pos)
  63 {
  64     // Use implementation-specific member function seekpos().
  65     return fpos_t_to_offset(pos.seekpos()) +
  66            stream_offset(std::streamoff(pos)) -
  67            stream_offset(std::streamoff(pos.seekpos()));
  68 }
  69
  70 # else // # if defined(_CPPLIB_VER) //----------------------------------------//
  71
  72         /* Old Dinkumware */
  73
  74 inline stream_offset position_to_offset(std::streampos pos)
  75 {
  76     // use implementation-specific member function get_fpos_t().
  77     return fpos_t_to_offset(pos.get_fpos_t()) +
  78            stream_offset(std::streamoff(pos)) -
  79            stream_offset(std::streamoff(pos.get_fpos_t()));
  80 }
  81
  82 # endif // # if defined(_CPPLIB_VER) //---------------------------------------//
  83 #else // Dinkumware //--------------------------------------------------------//
  84
  85         /* Non-Dinkumware */
  86
  87 inline std::streampos offset_to_position(stream_offset off) { return off; }
  88
  89 inline stream_offset position_to_offset(std::streampos pos) { return pos; }
  90
  91 #endif // Dinkumware //-------------------------------------------------------//
  92
  93 } } // End namespaces iostreams, boost.
  94
  95 #include <boost/iostreams/detail/config/enable_warnings.hpp>
  96
  97 #endif // #ifndef BOOST_IOSTREAMS_POSITIONING_HPP_INCLUDED