248 lines
6.5 KiB
C++
248 lines
6.5 KiB
C++
// -*- C++ -*-
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// Boost general library 'format' ---------------------------
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// See http://www.boost.org for updates, documentation, and revision history.
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// (C) Samuel Krempp 2001
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// krempp@crans.ens-cachan.fr
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// Permission to copy, use, modify, sell and
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// distribute this software is granted provided this copyright notice appears
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// in all copies. This software is provided "as is" without express or implied
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// warranty, and with no claim as to its suitability for any purpose.
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// ideas taken from Rüdiger Loos's format class
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// and Karl Nelson's ofstream
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// ----------------------------------------------------------------------------
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// feed_args.hpp : functions for processing each argument
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// (feed, feed_manip, and distribute)
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// ----------------------------------------------------------------------------
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#ifndef BOOST_FORMAT_FEED_ARGS_HPP
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#define BOOST_FORMAT_FEED_ARGS_HPP
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#include "boost/format/format_class.hpp"
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#include "boost/format/group.hpp"
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#include "boost/throw_exception.hpp"
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namespace boost {
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namespace io {
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namespace detail {
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namespace {
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inline
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void empty_buf(BOOST_IO_STD ostringstream & os) {
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static const std::string emptyStr;
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os.str(emptyStr);
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}
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void do_pad( std::string & s,
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std::streamsize w,
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const char c,
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std::ios::fmtflags f,
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bool center)
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// applies centered / left / right padding to the string s.
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// Effects : string s is padded.
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{
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std::streamsize n=w-s.size();
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if(n<=0) {
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return;
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}
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if(center)
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{
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s.reserve(w); // allocate once for the 2 inserts
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const std::streamsize n1 = n /2, n0 = n - n1;
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s.insert(s.begin(), n0, c);
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s.append(n1, c);
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}
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else
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{
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if(f & std::ios::left) {
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s.append(n, c);
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}
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else {
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s.insert(s.begin(), n, c);
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}
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}
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} // -do_pad(..)
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template<class T> inline
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void put_head(BOOST_IO_STD ostream& , const T& ) {
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}
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template<class T> inline
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void put_head( BOOST_IO_STD ostream& os, const group1<T>& x ) {
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os << group_head(x.a1_); // send the first N-1 items, not the last
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}
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template<class T> inline
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void put_last( BOOST_IO_STD ostream& os, const T& x ) {
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os << x ;
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}
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template<class T> inline
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void put_last( BOOST_IO_STD ostream& os, const group1<T>& x ) {
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os << group_last(x.a1_); // this selects the last element
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}
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#ifndef BOOST_NO_OVERLOAD_FOR_NON_CONST
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template<class T> inline
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void put_head( BOOST_IO_STD ostream& , T& ) {
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}
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template<class T> inline
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void put_last( BOOST_IO_STD ostream& os, T& x ) {
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os << x ;
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}
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#endif
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template<class T>
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void put( T x,
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const format_item& specs,
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std::string & res,
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BOOST_IO_STD ostringstream& oss_ )
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{
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// does the actual conversion of x, with given params, into a string
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// using the *supplied* strinstream. (the stream state is important)
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typedef std::string string_t;
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typedef format_item format_item_t;
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stream_format_state prev_state(oss_);
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specs.state_.apply_on(oss_);
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// in case x is a group, apply the manip part of it,
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// in order to find width
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put_head( oss_, x );
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empty_buf( oss_);
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const std::streamsize w=oss_.width();
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const std::ios::fmtflags fl=oss_.flags();
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const bool internal = (fl & std::ios::internal) != 0;
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const bool two_stepped_padding = internal
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&& ! ( specs.pad_scheme_ & format_item_t::spacepad )
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&& specs.truncate_ < 0 ;
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if(! two_stepped_padding)
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{
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if(w>0) // handle simple padding via do_pad, not natively in stream
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oss_.width(0);
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put_last( oss_, x);
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res = oss_.str();
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if (specs.truncate_ >= 0)
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res.erase(specs.truncate_);
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// complex pads :
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if(specs.pad_scheme_ & format_item_t::spacepad)
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{
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if( res.size()==0 || ( res[0]!='+' && res[0]!='-' ))
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{
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res.insert(res.begin(), 1, ' '); // insert 1 space at pos 0
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}
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}
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if(w > 0) // need do_pad
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{
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do_pad(res,w,oss_.fill(), fl, (specs.pad_scheme_ & format_item_t::centered) !=0 );
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}
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}
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else // 2-stepped padding
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{
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put_last( oss_, x); // oss_.width() may result in padding.
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res = oss_.str();
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if (specs.truncate_ >= 0)
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res.erase(specs.truncate_);
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if( res.size() - w > 0)
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{ // length w exceeded
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// either it was multi-output with first output padding up all width..
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// either it was one big arg and we are fine.
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empty_buf( oss_);
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oss_.width(0);
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put_last(oss_, x );
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string_t tmp = oss_.str(); // minimal-length output
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std::streamsize d;
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if( (d=w - tmp.size()) <=0 )
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{
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// minimal length is already >= w, so no padding (cool!)
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res.swap(tmp);
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}
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else
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{ // hum.. we need to pad (it was necessarily multi-output)
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typedef typename string_t::size_type size_type;
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size_type i = 0;
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while( i<tmp.size() && tmp[i] == res[i] ) // find where we should pad.
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++i;
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tmp.insert(i, static_cast<size_type>( d ), oss_.fill());
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res.swap( tmp );
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}
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}
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else
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{ // okay, only one thing was printed and padded, so res is fine.
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}
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}
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prev_state.apply_on(oss_);
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empty_buf( oss_);
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oss_.clear();
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} // end- put(..)
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} // local namespace
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template<class T>
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void distribute(basic_format& self, T x)
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// call put(x, ..) on every occurence of the current argument :
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{
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if(self.cur_arg_ >= self.num_args_)
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{
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if( self.exceptions() & too_many_args_bit )
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boost::throw_exception(too_many_args()); // too many variables have been supplied !
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else return;
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}
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for(unsigned long i=0; i < self.items_.size(); ++i)
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{
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if(self.items_[i].argN_ == self.cur_arg_)
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{
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put<T> (x, self.items_[i], self.items_[i].res_, self.oss_ );
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}
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}
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}
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template<class T>
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basic_format& feed(basic_format& self, T x)
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{
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if(self.dumped_) self.clear();
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distribute<T> (self, x);
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++self.cur_arg_;
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if(self.bound_.size() != 0)
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{
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while( self.cur_arg_ < self.num_args_ && self.bound_[self.cur_arg_] )
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++self.cur_arg_;
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}
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// this arg is finished, reset the stream's format state
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self.state0_.apply_on(self.oss_);
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return self;
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}
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} // namespace detail
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} // namespace io
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} // namespace boost
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#endif // BOOST_FORMAT_FEED_ARGS_HPP
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