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/config.hpp>
  18 #include <boost/cstdint.hpp>
  19 #include <boost/integer_traits.hpp>
  20 #include <boost/iostreams/detail/config/codecvt.hpp> // mbstate_t.
  21 #include <boost/iostreams/detail/ios.hpp> // streamoff, streampos.
  22
  23 // Must come last.
  24 #include <boost/iostreams/detail/config/disable_warnings.hpp>
  25
  26 #ifdef BOOST_NO_STDC_NAMESPACE
  27 namespace std { using ::fpos_t; }
  28 #endif
  29
  30 namespace boost { namespace iostreams {
  31
  32 typedef boost::intmax_t stream_offset;
  33
  34 inline std::streamoff stream_offset_to_streamoff(stream_offset off)
  35 { return static_cast<stream_offset>(off); }
  36
  37 template<typename PosType> // Hande custom pos_type's.
  38 inline stream_offset position_to_offset(PosType pos)
  39 { return std::streamoff(pos); }
  40
  41 #if ((defined(_YVALS) && !defined(__IBMCPP__)) || defined(_CPPLIB_VER)) && \
  42      !defined(__SGI_STL_PORT) && !defined(_STLPORT_VERSION) \
  43      && !defined(__QNX__) \
  44    /**/
  45
  46         /* Dinkumware */
  47
  48 inline std::streampos offset_to_position(stream_offset off)
  49 {
  50     // Use implementation-specific constructor.
  51     return std::streampos(std::mbstate_t(), off);
  52 }
  53
  54 inline stream_offset fpos_t_to_offset(std::fpos_t pos)
  55 { // Helper function.
  56 #if defined(_POSIX_) || (_INTEGRAL_MAX_BITS >= 64)
  57     return pos;
  58 #else
  59     return _FPOSOFF(pos);
  60 #endif
  61 }
  62
  63 # if defined(_CPPLIB_VER) //--------------------------------------------------//
  64
  65         /* Recent Dinkumware */
  66
  67 inline stream_offset position_to_offset(std::streampos pos)
  68 {
  69     // Use implementation-specific member function seekpos().
  70     return fpos_t_to_offset(pos.seekpos()) +
  71            stream_offset(std::streamoff(pos)) -
  72            stream_offset(std::streamoff(pos.seekpos()));
  73 }
  74
  75 # else // # if defined(_CPPLIB_VER) //----------------------------------------//
  76
  77         /* Old Dinkumware */
  78
  79 inline stream_offset position_to_offset(std::streampos pos)
  80 {
  81     // use implementation-specific member function get_fpos_t().
  82     return fpos_t_to_offset(pos.get_fpos_t()) +
  83            stream_offset(std::streamoff(pos)) -
  84            stream_offset(std::streamoff(pos.get_fpos_t()));
  85 }
  86
  87 # endif // # if defined(_CPPLIB_VER) //---------------------------------------//
  88 #else // Dinkumware //--------------------------------------------------------//
  89
  90         /* Non-Dinkumware */
  91
  92 inline std::streampos offset_to_position(stream_offset off) { return off; }
  93
  94 inline stream_offset position_to_offset(std::streampos pos) { return pos; }
  95
  96 #endif // Dinkumware //-------------------------------------------------------//
  97
  98 } } // End namespaces iostreams, boost.
  99
 100 #include <boost/iostreams/detail/config/enable_warnings.hpp>
 101
 102 #endif // #ifndef BOOST_IOSTREAMS_POSITIONING_HPP_INCLUDED