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241 lines
7.1 KiB
241 lines
7.1 KiB
// (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com) |
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// (C) Copyright 2005-2007 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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#ifndef BOOST_IOSTREAMS_READ_HPP_INCLUDED |
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#define BOOST_IOSTREAMS_READ_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> // DEDUCED_TYPENAME, MSVC. |
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#include <boost/detail/workaround.hpp> |
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#include <boost/iostreams/char_traits.hpp> |
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#include <boost/iostreams/detail/char_traits.hpp> |
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#include <boost/iostreams/detail/dispatch.hpp> |
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#include <boost/iostreams/detail/ios.hpp> // streamsize. |
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#include <boost/iostreams/detail/streambuf.hpp> |
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#include <boost/iostreams/detail/wrap_unwrap.hpp> |
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#include <boost/iostreams/operations_fwd.hpp> |
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#include <boost/mpl/if.hpp> |
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// Must come last. |
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#include <boost/iostreams/detail/config/disable_warnings.hpp> |
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namespace boost { namespace iostreams { |
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namespace detail { |
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template<typename T> |
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struct read_device_impl; |
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template<typename T> |
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struct read_filter_impl; |
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} // End namespace detail. |
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template<typename T> |
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typename int_type_of<T>::type get(T& t) |
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{ return detail::read_device_impl<T>::get(detail::unwrap(t)); } |
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template<typename T> |
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inline std::streamsize |
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read(T& t, typename char_type_of<T>::type* s, std::streamsize n) |
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{ return detail::read_device_impl<T>::read(detail::unwrap(t), s, n); } |
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template<typename T, typename Source> |
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std::streamsize |
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read(T& t, Source& src, typename char_type_of<T>::type* s, std::streamsize n) |
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{ return detail::read_filter_impl<T>::read(detail::unwrap(t), src, s, n); } |
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template<typename T> |
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bool putback(T& t, typename char_type_of<T>::type c) |
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{ return detail::read_device_impl<T>::putback(detail::unwrap(t), c); } |
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//----------------------------------------------------------------------------// |
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namespace detail { |
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// Helper function for adding -1 as EOF indicator. |
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inline std::streamsize check_eof(std::streamsize n) { return n != 0 ? n : -1; } |
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// Helper templates for reading from streambufs. |
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template<bool IsLinked> |
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struct true_eof_impl; |
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template<> |
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struct true_eof_impl<true> { |
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template<typename T> |
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static bool true_eof(T& t) { return t.true_eof(); } |
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}; |
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template<> |
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struct true_eof_impl<false> { |
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template<typename T> |
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static bool true_eof(T&) { return true; } |
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}; |
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template<typename T> |
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inline bool true_eof(T& t) |
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{ |
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const bool linked = is_linked<T>::value; |
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return true_eof_impl<linked>::true_eof(t); |
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} |
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//------------------Definition of read_device_impl----------------------------// |
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template<typename T> |
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struct read_device_impl |
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: mpl::if_< |
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detail::is_custom<T>, |
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operations<T>, |
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read_device_impl< |
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BOOST_DEDUCED_TYPENAME |
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detail::dispatch< |
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T, istream_tag, streambuf_tag, input |
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>::type |
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> |
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>::type |
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{ }; |
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template<> |
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struct read_device_impl<istream_tag> { |
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template<typename T> |
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static typename int_type_of<T>::type get(T& t) |
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{ return t.get(); } |
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template<typename T> |
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static std::streamsize |
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read(T& t, typename char_type_of<T>::type* s, std::streamsize n) |
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{ return check_eof(t.rdbuf()->sgetn(s, n)); } |
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template<typename T> |
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static bool putback(T& t, typename char_type_of<T>::type c) |
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{ |
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typedef typename char_type_of<T>::type char_type; |
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typedef BOOST_IOSTREAMS_CHAR_TRAITS(char_type) traits_type; |
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return !traits_type::eq_int_type( t.rdbuf()->sputbackc(c), |
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traits_type::eof() ); |
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} |
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}; |
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template<> |
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struct read_device_impl<streambuf_tag> { |
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template<typename T> |
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static typename int_type_of<T>::type |
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get(T& t) |
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{ // gcc 2.95 needs namespace qualification for char_traits. |
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typedef typename char_type_of<T>::type char_type; |
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typedef iostreams::char_traits<char_type> traits_type; |
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typename int_type_of<T>::type c; |
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return !traits_type::is_eof(c = t.sbumpc()) || |
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detail::true_eof(t) |
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? |
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c : traits_type::would_block(); |
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} |
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template<typename T> |
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static std::streamsize |
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read(T& t, typename char_type_of<T>::type* s, std::streamsize n) |
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{ |
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std::streamsize amt; |
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return (amt = t.sgetn(s, n)) != 0 ? |
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amt : |
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detail::true_eof(t) ? |
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-1 : |
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0; |
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} |
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template<typename T> |
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static bool putback(T& t, typename char_type_of<T>::type c) |
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{ // gcc 2.95 needs namespace qualification for char_traits. |
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typedef typename char_type_of<T>::type char_type; |
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typedef iostreams::char_traits<char_type> traits_type; |
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return !traits_type::is_eof(t.sputbackc(c)); |
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} |
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}; |
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template<> |
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struct read_device_impl<input> { |
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template<typename T> |
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static typename int_type_of<T>::type |
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get(T& t) |
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{ // gcc 2.95 needs namespace qualification for char_traits. |
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typedef typename char_type_of<T>::type char_type; |
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typedef iostreams::char_traits<char_type> traits_type; |
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char_type c; |
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std::streamsize amt; |
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return (amt = t.read(&c, 1)) == 1 ? |
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traits_type::to_int_type(c) : |
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amt == -1 ? |
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traits_type::eof() : |
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traits_type::would_block(); |
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} |
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template<typename T> |
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static std::streamsize |
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read(T& t, typename char_type_of<T>::type* s, std::streamsize n) |
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{ return t.read(s, n); } |
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template<typename T> |
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static bool putback(T& t, typename char_type_of<T>::type c) |
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{ // T must be Peekable. |
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return t.putback(c); |
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} |
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}; |
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//------------------Definition of read_filter_impl----------------------------// |
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template<typename T> |
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struct read_filter_impl |
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: mpl::if_< |
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detail::is_custom<T>, |
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operations<T>, |
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read_filter_impl< |
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BOOST_DEDUCED_TYPENAME |
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detail::dispatch< |
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T, multichar_tag, any_tag |
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>::type |
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> |
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>::type |
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{ }; |
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template<> |
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struct read_filter_impl<multichar_tag> { |
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template<typename T, typename Source> |
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static std::streamsize read |
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(T& t, Source& src, typename char_type_of<T>::type* s, std::streamsize n) |
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{ return t.read(src, s, n); } |
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}; |
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template<> |
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struct read_filter_impl<any_tag> { |
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template<typename T, typename Source> |
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static std::streamsize read |
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(T& t, Source& src, typename char_type_of<T>::type* s, std::streamsize n) |
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{ // gcc 2.95 needs namespace qualification for char_traits. |
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typedef typename char_type_of<T>::type char_type; |
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typedef iostreams::char_traits<char_type> traits_type; |
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for (std::streamsize off = 0; off < n; ++off) { |
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typename traits_type::int_type c = t.get(src); |
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if (traits_type::is_eof(c)) |
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return check_eof(off); |
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if (traits_type::would_block(c)) |
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return off; |
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s[off] = traits_type::to_char_type(c); |
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} |
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return n; |
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} |
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}; |
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} // End namespace detail. |
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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_READ_HPP_INCLUDED
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