[29] | 1 | // (C) Copyright Jonathan Turkanis 2003. |
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| 2 | // Distributed under the Boost Software License, Version 1.0. (See accompanying |
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| 3 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.) |
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| 4 | |
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| 5 | // See http://www.boost.org/libs/iostreams for documentation. |
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| 6 | |
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| 7 | #ifndef BOOST_IOSTREAMS_SEEK_HPP_INCLUDED |
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| 8 | #define BOOST_IOSTREAMS_SEEK_HPP_INCLUDED |
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| 9 | |
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| 10 | #if defined(_MSC_VER) && (_MSC_VER >= 1020) |
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| 11 | # pragma once |
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| 12 | #endif |
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| 13 | |
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| 14 | #include <boost/config.hpp> // DEDUCED_TYPENAME, MSVC. |
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| 15 | #include <boost/integer_traits.hpp> |
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| 16 | #include <boost/iostreams/categories.hpp> |
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| 17 | #include <boost/iostreams/detail/dispatch.hpp> |
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| 18 | #include <boost/iostreams/detail/ios.hpp> // streamsize, seekdir, openmode. |
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| 19 | #include <boost/iostreams/detail/streambuf.hpp> |
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| 20 | #include <boost/iostreams/detail/wrap_unwrap.hpp> |
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| 21 | #include <boost/iostreams/operations_fwd.hpp> |
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| 22 | #include <boost/iostreams/positioning.hpp> |
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| 23 | #include <boost/mpl/if.hpp> |
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| 24 | |
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| 25 | // Must come last. |
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| 26 | #include <boost/iostreams/detail/config/disable_warnings.hpp> |
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| 27 | |
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| 28 | namespace boost { namespace iostreams { |
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| 29 | |
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| 30 | namespace detail { |
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| 31 | |
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| 32 | template<typename T> |
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| 33 | struct seek_device_impl; |
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| 34 | |
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| 35 | template<typename T> |
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| 36 | struct seek_filter_impl; |
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| 37 | |
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| 38 | } // End namespace detail. |
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| 39 | |
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| 40 | template<typename T> |
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| 41 | inline std::streampos |
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| 42 | seek( T& t, stream_offset off, BOOST_IOS::seekdir way, |
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| 43 | BOOST_IOS::openmode which = BOOST_IOS::in | BOOST_IOS::out ) |
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| 44 | { |
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| 45 | using namespace detail; |
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| 46 | return seek_device_impl<T>::seek(detail::unwrap(t), off, way, which); |
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| 47 | } |
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| 48 | |
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| 49 | template<typename T, typename Device> |
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| 50 | inline std::streampos |
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| 51 | seek( T& t, Device& dev, stream_offset off, BOOST_IOS::seekdir way, |
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| 52 | BOOST_IOS::openmode which = BOOST_IOS::in | BOOST_IOS::out ) |
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| 53 | { |
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| 54 | using namespace detail; |
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| 55 | return seek_filter_impl<T>::seek(detail::unwrap(t), dev, off, way, which); |
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| 56 | } |
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| 57 | |
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| 58 | namespace detail { |
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| 59 | |
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| 60 | //------------------Definition of seek_device_impl----------------------------// |
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| 61 | |
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| 62 | template<typename T> |
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| 63 | struct seek_device_impl |
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| 64 | : mpl::if_< |
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| 65 | is_custom<T>, |
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| 66 | operations<T>, |
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| 67 | seek_device_impl< |
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| 68 | BOOST_DEDUCED_TYPENAME |
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| 69 | dispatch< |
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| 70 | T, iostream_tag, istream_tag, ostream_tag, |
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| 71 | streambuf_tag, two_head, any_tag |
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| 72 | >::type |
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| 73 | > |
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| 74 | >::type |
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| 75 | { }; |
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| 76 | |
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| 77 | struct seek_impl_basic_ios { |
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| 78 | template<typename T> |
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| 79 | static std::streampos seek( T& t, stream_offset off, |
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| 80 | BOOST_IOS::seekdir way, |
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| 81 | BOOST_IOS::openmode which ) |
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| 82 | { |
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| 83 | if ( way == BOOST_IOS::beg && |
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| 84 | ( off < integer_traits<std::streamoff>::const_min || |
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| 85 | off > integer_traits<std::streamoff>::const_max ) ) |
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| 86 | { |
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| 87 | return t.rdbuf()->pubseekpos(offset_to_position(off)); |
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| 88 | } else { |
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| 89 | return t.rdbuf()->pubseekoff(off, way, which); |
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| 90 | } |
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| 91 | } |
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| 92 | }; |
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| 93 | |
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| 94 | template<> |
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| 95 | struct seek_device_impl<iostream_tag> : seek_impl_basic_ios { }; |
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| 96 | |
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| 97 | template<> |
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| 98 | struct seek_device_impl<istream_tag> : seek_impl_basic_ios { }; |
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| 99 | |
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| 100 | template<> |
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| 101 | struct seek_device_impl<ostream_tag> : seek_impl_basic_ios { }; |
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| 102 | |
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| 103 | template<> |
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| 104 | struct seek_device_impl<streambuf_tag> { |
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| 105 | template<typename T> |
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| 106 | static std::streampos seek( T& t, stream_offset off, |
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| 107 | BOOST_IOS::seekdir way, |
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| 108 | BOOST_IOS::openmode which ) |
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| 109 | { |
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| 110 | if ( way == BOOST_IOS::beg && |
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| 111 | ( off < integer_traits<std::streamoff>::const_min || |
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| 112 | off > integer_traits<std::streamoff>::const_max ) ) |
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| 113 | { |
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| 114 | return t.BOOST_IOSTREAMS_PUBSEEKPOS(offset_to_position(off)); |
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| 115 | } else { |
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| 116 | return t.BOOST_IOSTREAMS_PUBSEEKOFF(off, way, which); |
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| 117 | } |
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| 118 | } |
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| 119 | }; |
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| 120 | |
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| 121 | template<> |
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| 122 | struct seek_device_impl<two_head> { |
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| 123 | template<typename T> |
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| 124 | static std::streampos seek( T& t, stream_offset off, |
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| 125 | BOOST_IOS::seekdir way, |
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| 126 | BOOST_IOS::openmode which ) |
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| 127 | { return t.seek(off, way, which); } |
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| 128 | }; |
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| 129 | |
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| 130 | template<> |
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| 131 | struct seek_device_impl<any_tag> { |
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| 132 | template<typename T> |
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| 133 | static std::streampos seek( T& t, stream_offset off, |
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| 134 | BOOST_IOS::seekdir way, |
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| 135 | BOOST_IOS::openmode ) |
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| 136 | { return t.seek(off, way); } |
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| 137 | }; |
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| 138 | |
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| 139 | //------------------Definition of seek_filter_impl----------------------------// |
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| 140 | |
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| 141 | template<typename T> |
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| 142 | struct seek_filter_impl |
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| 143 | : mpl::if_< |
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| 144 | is_custom<T>, |
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| 145 | operations<T>, |
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| 146 | seek_filter_impl< |
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| 147 | BOOST_DEDUCED_TYPENAME |
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| 148 | dispatch<T, two_head, any_tag>::type |
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| 149 | > |
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| 150 | >::type |
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| 151 | { }; |
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| 152 | |
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| 153 | template<> |
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| 154 | struct seek_filter_impl<two_head> { |
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| 155 | template<typename T, typename Device> |
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| 156 | static std::streampos seek( T& t, Device& d, |
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| 157 | stream_offset off, |
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| 158 | BOOST_IOS::seekdir way, |
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| 159 | BOOST_IOS::openmode which ) |
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| 160 | { return t.seek(d, off, way, which); } |
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| 161 | }; |
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| 162 | |
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| 163 | template<> |
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| 164 | struct seek_filter_impl<any_tag> { |
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| 165 | template<typename T, typename Device> |
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| 166 | static std::streampos seek( T& t, Device& d, |
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| 167 | stream_offset off, |
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| 168 | BOOST_IOS::seekdir way, |
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| 169 | BOOST_IOS::openmode ) |
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| 170 | { return t.seek(d, off, way); } |
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| 171 | }; |
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| 172 | |
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| 173 | } // End namespace detail. |
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| 174 | |
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| 175 | } } // End namespaces iostreams, boost. |
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| 176 | |
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| 177 | #include <boost/iostreams/detail/config/enable_warnings.hpp> |
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| 178 | |
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| 179 | #endif // #ifndef BOOST_IOSTREAMS_SEEK_HPP_INCLUDED |
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