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