// (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)

// (C) Copyright 2003-2007 Jonathan Turkanis

// Distributed under the Boost Software License, Version 1.0. (See accompanying

// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)



// See http://www.boost.org/libs/iostreams for documentation.



// Thanks to Gareth Sylvester-Bradley for the Dinkumware versions of the

// positioning functions.



#ifndef BOOST_IOSTREAMS_POSITIONING_HPP_INCLUDED

#define BOOST_IOSTREAMS_POSITIONING_HPP_INCLUDED



#if defined(_MSC_VER) && (_MSC_VER >= 1020)

# pragma once

#endif



#include <boost/config.hpp>

#include <boost/cstdint.hpp>

#include <boost/integer_traits.hpp>

#include <boost/iostreams/detail/config/codecvt.hpp> // mbstate_t.

#include <boost/iostreams/detail/config/fpos.hpp>

#include <boost/iostreams/detail/ios.hpp> // streamoff, streampos.



// Must come last.

#include <boost/iostreams/detail/config/disable_warnings.hpp> 



#ifdef BOOST_NO_STDC_NAMESPACE

namespace std { using ::fpos_t; }

#endif



namespace boost { namespace iostreams {

                    

//------------------Definition of stream_offset-------------------------------//



typedef boost::intmax_t stream_offset;



//------------------Definition of stream_offset_to_streamoff------------------//



inline std::streamoff stream_offset_to_streamoff(stream_offset off)

{ return static_cast<stream_offset>(off); }



//------------------Definition of offset_to_position--------------------------//



# ifndef BOOST_IOSTREAMS_HAS_DINKUMWARE_FPOS



inline std::streampos offset_to_position(stream_offset off) { return off; }



# else // # ifndef BOOST_IOSTREAMS_HAS_DINKUMWARE_FPOS



inline std::streampos offset_to_position(stream_offset off)

{ return std::streampos(std::mbstate_t(), off); }



# endif // # ifndef BOOST_IOSTREAMS_HAS_DINKUMWARE_FPOS



//------------------Definition of position_to_offset--------------------------//



// Hande custom pos_type's

template<typename PosType> 

inline stream_offset position_to_offset(PosType pos)

{ return std::streamoff(pos); }



# ifndef BOOST_IOSTREAMS_HAS_DINKUMWARE_FPOS



inline stream_offset position_to_offset(std::streampos pos) { return pos; }



# else // # ifndef BOOST_IOSTREAMS_HAS_DINKUMWARE_FPOS



// In the Dinkumware standard library, a std::streampos consists of two stream

// offsets -- _Fpos, of type std::fpos_t, and _Myoff, of type std::streamoff --

// together with a conversion state. A std::streampos is converted to a 

// boost::iostreams::stream_offset by extracting the two stream offsets and

// summing them. The value of _Fpos can be extracted using the implementation-

// defined member functions seekpos() or get_fpos_t(), depending on the 

// Dinkumware version. The value of _Myoff cannot be extracted directly, but can

// be calculated as the difference between the result of converting the 

// std::fpos to a std::streamoff and the result of converting the member _Fpos

// to a long. The latter operation is accomplished with the macro _FPOSOFF, 

// which works correctly on platforms where std::fpos_t is an integral type and 

// platforms where it is a struct



// Converts a std::fpos_t to a stream_offset

inline stream_offset fpos_t_to_offset(std::fpos_t pos)

{

#  if defined(_POSIX_) || (_INTEGRAL_MAX_BITS >= 64) || defined(__IBMCPP__)

    return pos;

#  else

    return _FPOSOFF(pos);

#  endif

}



// Extracts the member _Fpos from a std::fpos

inline std::fpos_t streampos_to_fpos_t(std::streampos pos)

{

#  if defined (_CPPLIB_VER) || defined(__IBMCPP__)

    return pos.seekpos();

#  else

    return pos.get_fpos_t();

#  endif

}



inline stream_offset position_to_offset(std::streampos pos)

{

    return fpos_t_to_offset(streampos_to_fpos_t(pos)) +

           static_cast<stream_offset>(static_cast<std::streamoff>(pos)) -

           static_cast<stream_offset>(_FPOSOFF(streampos_to_fpos_t(pos)));

}



# endif // # ifndef BOOST_IOSTREAMS_HAS_DINKUMWARE_FPOS 



} } // End namespaces iostreams, boost.



#include <boost/iostreams/detail/config/enable_warnings.hpp> 



#endif // #ifndef BOOST_IOSTREAMS_POSITIONING_HPP_INCLUDED

