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117 lines
4.0 KiB
117 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) && (_MSC_VER >= 1020) |
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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 _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 _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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_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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