Chris@16: // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
Chris@16: // (C) Copyright 2003-2007 Jonathan Turkanis
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@16: // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)
Chris@16: 
Chris@16: // See http://www.boost.org/libs/iostreams for documentation.
Chris@16: 
Chris@16: // Thanks to Gareth Sylvester-Bradley for the Dinkumware versions of the
Chris@16: // positioning functions.
Chris@16: 
Chris@16: #ifndef BOOST_IOSTREAMS_POSITIONING_HPP_INCLUDED
Chris@16: #define BOOST_IOSTREAMS_POSITIONING_HPP_INCLUDED
Chris@16: 
Chris@16: #if defined(_MSC_VER) && (_MSC_VER >= 1020)
Chris@16: # pragma once
Chris@16: #endif
Chris@16: 
Chris@16: #include <boost/config.hpp>
Chris@16: #include <boost/cstdint.hpp>
Chris@16: #include <boost/integer_traits.hpp>
Chris@16: #include <boost/iostreams/detail/config/codecvt.hpp> // mbstate_t.
Chris@16: #include <boost/iostreams/detail/config/fpos.hpp>
Chris@16: #include <boost/iostreams/detail/ios.hpp> // streamoff, streampos.
Chris@16: 
Chris@16: // Must come last.
Chris@16: #include <boost/iostreams/detail/config/disable_warnings.hpp> 
Chris@16: 
Chris@16: #ifdef BOOST_NO_STDC_NAMESPACE
Chris@16: namespace std { using ::fpos_t; }
Chris@16: #endif
Chris@16: 
Chris@16: namespace boost { namespace iostreams {
Chris@16:                     
Chris@16: //------------------Definition of stream_offset-------------------------------//
Chris@16: 
Chris@16: typedef boost::intmax_t stream_offset;
Chris@16: 
Chris@16: //------------------Definition of stream_offset_to_streamoff------------------//
Chris@16: 
Chris@16: inline std::streamoff stream_offset_to_streamoff(stream_offset off)
Chris@16: { return static_cast<stream_offset>(off); }
Chris@16: 
Chris@16: //------------------Definition of offset_to_position--------------------------//
Chris@16: 
Chris@16: # ifndef BOOST_IOSTREAMS_HAS_DINKUMWARE_FPOS
Chris@16: 
Chris@16: inline std::streampos offset_to_position(stream_offset off) { return off; }
Chris@16: 
Chris@16: # else // # ifndef BOOST_IOSTREAMS_HAS_DINKUMWARE_FPOS
Chris@16: 
Chris@16: inline std::streampos offset_to_position(stream_offset off)
Chris@16: { return std::streampos(std::mbstate_t(), off); }
Chris@16: 
Chris@16: # endif // # ifndef BOOST_IOSTREAMS_HAS_DINKUMWARE_FPOS
Chris@16: 
Chris@16: //------------------Definition of position_to_offset--------------------------//
Chris@16: 
Chris@16: // Hande custom pos_type's
Chris@16: template<typename PosType> 
Chris@16: inline stream_offset position_to_offset(PosType pos)
Chris@16: { return std::streamoff(pos); }
Chris@16: 
Chris@16: # ifndef BOOST_IOSTREAMS_HAS_DINKUMWARE_FPOS
Chris@16: 
Chris@16: inline stream_offset position_to_offset(std::streampos pos) { return pos; }
Chris@16: 
Chris@16: # else // # ifndef BOOST_IOSTREAMS_HAS_DINKUMWARE_FPOS
Chris@16: 
Chris@16: // In the Dinkumware standard library, a std::streampos consists of two stream
Chris@16: // offsets -- _Fpos, of type std::fpos_t, and _Myoff, of type std::streamoff --
Chris@16: // together with a conversion state. A std::streampos is converted to a 
Chris@16: // boost::iostreams::stream_offset by extracting the two stream offsets and
Chris@16: // summing them. The value of _Fpos can be extracted using the implementation-
Chris@16: // defined member functions seekpos() or get_fpos_t(), depending on the 
Chris@16: // Dinkumware version. The value of _Myoff cannot be extracted directly, but can
Chris@16: // be calculated as the difference between the result of converting the 
Chris@16: // std::fpos to a std::streamoff and the result of converting the member _Fpos
Chris@16: // to a long. The latter operation is accomplished with the macro _FPOSOFF, 
Chris@16: // which works correctly on platforms where std::fpos_t is an integral type and 
Chris@16: // platforms where it is a struct
Chris@16: 
Chris@16: // Converts a std::fpos_t to a stream_offset
Chris@16: inline stream_offset fpos_t_to_offset(std::fpos_t pos)
Chris@16: {
Chris@16: #  if defined(_POSIX_) || (_INTEGRAL_MAX_BITS >= 64) || defined(__IBMCPP__)
Chris@16:     return pos;
Chris@16: #  else
Chris@16:     return _FPOSOFF(pos);
Chris@16: #  endif
Chris@16: }
Chris@16: 
Chris@16: // Extracts the member _Fpos from a std::fpos
Chris@16: inline std::fpos_t streampos_to_fpos_t(std::streampos pos)
Chris@16: {
Chris@16: #  if defined (_CPPLIB_VER) || defined(__IBMCPP__)
Chris@16:     return pos.seekpos();
Chris@16: #  else
Chris@16:     return pos.get_fpos_t();
Chris@16: #  endif
Chris@16: }
Chris@16: 
Chris@16: inline stream_offset position_to_offset(std::streampos pos)
Chris@16: {
Chris@16:     return fpos_t_to_offset(streampos_to_fpos_t(pos)) +
Chris@16:         static_cast<stream_offset>(
Chris@16:             static_cast<std::streamoff>(pos) -
Chris@16:             _FPOSOFF(streampos_to_fpos_t(pos))
Chris@16:         );
Chris@16: }
Chris@16: 
Chris@16: # endif // # ifndef BOOST_IOSTREAMS_HAS_DINKUMWARE_FPOS 
Chris@16: 
Chris@16: } } // End namespaces iostreams, boost.
Chris@16: 
Chris@16: #include <boost/iostreams/detail/config/enable_warnings.hpp> 
Chris@16: 
Chris@16: #endif // #ifndef BOOST_IOSTREAMS_POSITIONING_HPP_INCLUDED