// Copyright (c) 2009-2020 Vladimir Batov.
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// Use, modification and distribution are subject to the Boost Software License,
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// Version 1.0. See http://www.boost.org/LICENSE_1_0.txt.
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#ifndef BOOST_CONVERT_STRINGSTREAM_BASED_CONVERTER_HPP
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#define BOOST_CONVERT_STRINGSTREAM_BASED_CONVERTER_HPP
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#include <boost/convert/parameters.hpp>
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#include <boost/convert/detail/is_string.hpp>
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#include <boost/make_default.hpp>
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#include <sstream>
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#include <iomanip>
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#define BOOST_CNV_STRING_ENABLE \
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template<typename string_type, typename type> \
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typename std::enable_if<cnv::is_string<string_type>::value, void>::type \
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operator()
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#define BOOST_CNV_PARAM_SET(param_name) \
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template <typename argument_pack> \
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void set_( \
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argument_pack const& arg, \
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cnv::parameter::type::param_name, \
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mpl::true_)
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#define BOOST_CNV_PARAM_TRY(param_name) \
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this->set_( \
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arg, \
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cnv::parameter::type::param_name(), \
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typename mpl::has_key< \
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argument_pack, cnv::parameter::type::param_name>::type());
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namespace boost { namespace cnv
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{
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template<class Char> struct basic_stream;
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using cstream = boost::cnv::basic_stream<char>;
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using wstream = boost::cnv::basic_stream<wchar_t>;
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}}
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template<class Char>
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struct boost::cnv::basic_stream
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{
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// C01. In string-to-type conversions the "string" must be a CONTIGUOUS ARRAY of
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// characters because "ibuffer_type" uses/relies on that (it deals with char_type*).
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// C02. Use the provided "string_in" as the input (read-from) buffer and, consequently,
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// avoid the overhead associated with stream_.str(string_in) --
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// copying of the content into internal buffer.
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// C03. The "strbuf.gptr() != strbuf.egptr()" check replaces "istream.eof() != true"
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// which for some reason does not work when we try converting the "true" string
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// to "bool" with std::boolalpha set. Seems that istream state gets unsynced compared
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// to the actual underlying buffer.
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using char_type = Char;
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using this_type = boost::cnv::basic_stream<char_type>;
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using stream_type = std::basic_stringstream<char_type>;
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using istream_type = std::basic_istream<char_type>;
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using buffer_type = std::basic_streambuf<char_type>;
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using stdstr_type = std::basic_string<char_type>;
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using manipulator_type = std::ios_base& (*)(std::ios_base&);
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struct ibuffer_type : buffer_type
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{
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using buffer_type::eback;
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using buffer_type::gptr;
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using buffer_type::egptr;
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ibuffer_type(char_type const* beg, std::size_t sz) //C01
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{
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char_type* b = const_cast<char_type*>(beg);
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buffer_type::setg(b, b, b + sz);
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}
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};
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struct obuffer_type : buffer_type
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{
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using buffer_type::pbase;
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using buffer_type::pptr;
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using buffer_type::epptr;
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};
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basic_stream () : stream_(std::ios_base::in | std::ios_base::out) {}
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basic_stream (this_type&& other) : stream_(std::move(other.stream_)) {}
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basic_stream(this_type const&) = delete;
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this_type& operator=(this_type const&) = delete;
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BOOST_CNV_STRING_ENABLE(type const& v, optional<string_type>& s) const { to_str(v, s); }
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BOOST_CNV_STRING_ENABLE(string_type const& s, optional<type>& r) const { str_to(cnv::range<string_type const>(s), r); }
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// Resolve ambiguity of string-to-string
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template<typename type> void operator()( char_type const* s, optional<type>& r) const { str_to(cnv::range< char_type const*>(s), r); }
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template<typename type> void operator()(stdstr_type const& s, optional<type>& r) const { str_to(cnv::range<stdstr_type const>(s), r); }
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// Formatters
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template<typename manipulator>
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typename boost::disable_if<boost::parameter::is_argument_pack<manipulator>, this_type&>::type
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operator()(manipulator m) { return (this->stream_ << m, *this); }
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this_type& operator() (manipulator_type m) { return (m(stream_), *this); }
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this_type& operator() (std::locale const& l) { return (stream_.imbue(l), *this); }
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template<typename argument_pack>
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typename std::enable_if<boost::parameter::is_argument_pack<argument_pack>::value, this_type&>::type
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operator()(argument_pack const& arg)
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{
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BOOST_CNV_PARAM_TRY(precision);
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BOOST_CNV_PARAM_TRY(width);
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BOOST_CNV_PARAM_TRY(fill);
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BOOST_CNV_PARAM_TRY(uppercase);
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BOOST_CNV_PARAM_TRY(skipws);
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BOOST_CNV_PARAM_TRY(adjust);
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BOOST_CNV_PARAM_TRY(base);
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BOOST_CNV_PARAM_TRY(notation);
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return *this;
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}
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private:
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template<typename argument_pack, typename keyword_tag>
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void set_(argument_pack const&, keyword_tag, mpl::false_) {}
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BOOST_CNV_PARAM_SET (locale) { stream_.imbue(arg[cnv::parameter::locale]); }
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BOOST_CNV_PARAM_SET (precision) { stream_.precision(arg[cnv::parameter::precision]); }
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BOOST_CNV_PARAM_SET (width) { stream_.width(arg[cnv::parameter::width]); }
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BOOST_CNV_PARAM_SET (fill) { stream_.fill(arg[cnv::parameter::fill]); }
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BOOST_CNV_PARAM_SET (uppercase)
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{
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bool uppercase = arg[cnv::parameter::uppercase];
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uppercase ? (void) stream_.setf(std::ios::uppercase) : stream_.unsetf(std::ios::uppercase);
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}
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BOOST_CNV_PARAM_SET (skipws)
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{
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bool skipws = arg[cnv::parameter::skipws];
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skipws ? (void) stream_.setf(std::ios::skipws) : stream_.unsetf(std::ios::skipws);
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}
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BOOST_CNV_PARAM_SET (adjust)
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{
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cnv::adjust adjust = arg[cnv::parameter::adjust];
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/**/ if (adjust == cnv::adjust:: left) stream_.setf(std::ios::adjustfield, std::ios:: left);
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else if (adjust == cnv::adjust::right) stream_.setf(std::ios::adjustfield, std::ios::right);
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else BOOST_ASSERT(!"Not implemented");
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}
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BOOST_CNV_PARAM_SET (base)
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{
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cnv::base base = arg[cnv::parameter::base];
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/**/ if (base == cnv::base::dec) std::dec(stream_);
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else if (base == cnv::base::hex) std::hex(stream_);
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else if (base == cnv::base::oct) std::oct(stream_);
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else BOOST_ASSERT(!"Not implemented");
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}
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BOOST_CNV_PARAM_SET (notation)
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{
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cnv::notation notation = arg[cnv::parameter::notation];
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/**/ if (notation == cnv::notation:: fixed) std::fixed(stream_);
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else if (notation == cnv::notation::scientific) std::scientific(stream_);
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else BOOST_ASSERT(!"Not implemented");
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}
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template<typename string_type, typename out_type> void str_to(cnv::range<string_type>, optional<out_type>&) const;
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template<typename string_type, typename in_type> void to_str(in_type const&, optional<string_type>&) const;
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mutable stream_type stream_;
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};
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template<typename char_type>
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template<typename string_type, typename in_type>
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inline
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void
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boost::cnv::basic_stream<char_type>::to_str(
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in_type const& value_in,
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boost::optional<string_type>& string_out) const
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{
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stream_.clear(); // Clear the flags
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stream_.str(stdstr_type()); // Clear/empty the content of the stream
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if (!(stream_ << value_in).fail())
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{
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buffer_type* buf = stream_.rdbuf();
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obuffer_type* obuf = reinterpret_cast<obuffer_type*>(buf);
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char_type const* beg = obuf->pbase();
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char_type const* end = obuf->pptr();
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string_out = string_type(beg, end); // Instead of stream_.str();
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}
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}
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template<typename char_type>
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template<typename string_type, typename out_type>
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inline
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void
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boost::cnv::basic_stream<char_type>::str_to(
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boost::cnv::range<string_type> string_in,
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boost::optional<out_type>& result_out) const
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{
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if (string_in.empty ()) return;
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istream_type& istream = stream_;
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buffer_type* oldbuf = istream.rdbuf();
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char_type const* beg = &*string_in.begin();
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std::size_t sz = string_in.end() - string_in.begin();
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ibuffer_type newbuf (beg, sz); //C02
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istream.rdbuf(&newbuf);
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istream.clear(); // Clear the flags
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istream >> *(result_out = boost::make_default<out_type>());
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if (istream.fail() || newbuf.gptr() != newbuf.egptr()/*C03*/)
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result_out = boost::none;
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istream.rdbuf(oldbuf);
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}
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#undef BOOST_CNV_STRING_ENABLE
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#undef BOOST_CNV_PARAM_SET
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#undef BOOST_CNV_PARAM_TRY
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#endif // BOOST_CONVERT_STRINGSTREAM_BASED_CONVERTER_HPP
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