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authorEelco Dolstra <e.dolstra@tudelft.nl>2003-06-27 13:41:42 +0000
committerEelco Dolstra <e.dolstra@tudelft.nl>2003-06-27 13:41:42 +0000
commitbb03c45ca03e038c8b74fc1410f48d02ade4c59b (patch)
tree131afdf9d4b308e4d1fff6089f2ab1923c862e02 /boost/format/feed_args.hpp
parentd4c3edfaba91a0e5e1e9528749e5b1e178511a6d (diff)
* Added the Boost format library which provides a safe printf
replacement.
Diffstat (limited to 'boost/format/feed_args.hpp')
-rw-r--r--boost/format/feed_args.hpp248
1 files changed, 248 insertions, 0 deletions
diff --git a/boost/format/feed_args.hpp b/boost/format/feed_args.hpp
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+// -*- C++ -*-
+// Boost general library 'format' ---------------------------
+// See http://www.boost.org for updates, documentation, and revision history.
+
+// (C) Samuel Krempp 2001
+// krempp@crans.ens-cachan.fr
+// Permission to copy, use, modify, sell and
+// distribute this software is granted provided this copyright notice appears
+// in all copies. This software is provided "as is" without express or implied
+// warranty, and with no claim as to its suitability for any purpose.
+
+// ideas taken from Rüdiger Loos's format class
+// and Karl Nelson's ofstream
+
+// ----------------------------------------------------------------------------
+// feed_args.hpp : functions for processing each argument
+// (feed, feed_manip, and distribute)
+// ----------------------------------------------------------------------------
+
+
+#ifndef BOOST_FORMAT_FEED_ARGS_HPP
+#define BOOST_FORMAT_FEED_ARGS_HPP
+
+#include "boost/format/format_class.hpp"
+#include "boost/format/group.hpp"
+
+//#include "boost/throw_exception.hpp"
+
+namespace boost {
+namespace io {
+namespace detail {
+namespace {
+
+ template<class Tr, class Ch> inline
+ void empty_buf(BOOST_IO_STD basic_ostringstream<Ch,Tr> & os) {
+ static const std::basic_string<Ch, Tr> emptyStr;
+ os.str(emptyStr);
+ }
+
+ template<class Ch, class Tr>
+ void do_pad( std::basic_string<Ch,Tr> & s,
+ std::streamsize w,
+ const Ch c,
+ std::ios_base::fmtflags f,
+ bool center)
+ // applies centered / left / right padding to the string s.
+ // Effects : string s is padded.
+ {
+ std::streamsize n=w-s.size();
+ if(n<=0) {
+ return;
+ }
+ if(center)
+ {
+ s.reserve(w); // allocate once for the 2 inserts
+ const std::streamsize n1 = n /2, n0 = n - n1;
+ s.insert(s.begin(), n0, c);
+ s.append(n1, c);
+ }
+ else
+ {
+ if(f & std::ios_base::left) {
+ s.append(n, c);
+ }
+ else {
+ s.insert(s.begin(), n, c);
+ }
+ }
+ } // -do_pad(..)
+
+
+ template< class Ch, class Tr, class T> inline
+ void put_head(BOOST_IO_STD basic_ostream<Ch, Tr>& , const T& ) {
+ }
+
+ template< class Ch, class Tr, class T> inline
+ void put_head( BOOST_IO_STD basic_ostream<Ch, Tr>& os, const group1<T>& x ) {
+ os << group_head(x.a1_); // send the first N-1 items, not the last
+ }
+
+ template< class Ch, class Tr, class T> inline
+ void put_last( BOOST_IO_STD basic_ostream<Ch, Tr>& os, const T& x ) {
+ os << x ;
+ }
+
+ template< class Ch, class Tr, class T> inline
+ void put_last( BOOST_IO_STD basic_ostream<Ch, Tr>& os, const group1<T>& x ) {
+ os << group_last(x.a1_); // this selects the last element
+ }
+
+#ifndef BOOST_NO_OVERLOAD_FOR_NON_CONST
+ template< class Ch, class Tr, class T> inline
+ void put_head( BOOST_IO_STD basic_ostream<Ch, Tr>& , T& ) {
+ }
+
+ template< class Ch, class Tr, class T> inline
+ void put_last( BOOST_IO_STD basic_ostream<Ch, Tr>& os, T& x ) {
+ os << x ;
+ }
+#endif
+
+
+
+
+template< class Ch, class Tr, class T>
+void put( T x,
+ const format_item<Ch, Tr>& specs,
+ std::basic_string<Ch, Tr> & res,
+ BOOST_IO_STD basic_ostringstream<Ch, Tr>& oss_ )
+{
+ // does the actual conversion of x, with given params, into a string
+ // using the *supplied* strinstream. (the stream state is important)
+
+ typedef std::basic_string<Ch, Tr> string_t;
+ typedef format_item<Ch, Tr> format_item_t;
+
+ stream_format_state<Ch, Tr> prev_state(oss_);
+
+ specs.state_.apply_on(oss_);
+
+ // in case x is a group, apply the manip part of it,
+ // in order to find width
+ put_head( oss_, x );
+ empty_buf( oss_);
+
+ const std::streamsize w=oss_.width();
+ const std::ios_base::fmtflags fl=oss_.flags();
+ const bool internal = (fl & std::ios_base::internal) != 0;
+ const bool two_stepped_padding = internal
+ && ! ( specs.pad_scheme_ & format_item_t::spacepad )
+ && specs.truncate_ < 0 ;
+
+
+ if(! two_stepped_padding)
+ {
+ if(w>0) // handle simple padding via do_pad, not natively in stream
+ oss_.width(0);
+ put_last( oss_, x);
+ res = oss_.str();
+
+ if (specs.truncate_ >= 0)
+ res.erase(specs.truncate_);
+
+ // complex pads :
+ if(specs.pad_scheme_ & format_item_t::spacepad)
+ {
+ if( res.size()==0 || ( res[0]!='+' && res[0]!='-' ))
+ {
+ res.insert(res.begin(), 1, ' '); // insert 1 space at pos 0
+ }
+ }
+ if(w > 0) // need do_pad
+ {
+ do_pad(res,w,oss_.fill(), fl, (specs.pad_scheme_ & format_item_t::centered) !=0 );
+ }
+ }
+ else // 2-stepped padding
+ {
+ put_last( oss_, x); // oss_.width() may result in padding.
+ res = oss_.str();
+
+ if (specs.truncate_ >= 0)
+ res.erase(specs.truncate_);
+
+ if( res.size() - w > 0)
+ { // length w exceeded
+ // either it was multi-output with first output padding up all width..
+ // either it was one big arg and we are fine.
+ empty_buf( oss_);
+ oss_.width(0);
+ put_last(oss_, x );
+ string_t tmp = oss_.str(); // minimal-length output
+ std::streamsize d;
+ if( (d=w - tmp.size()) <=0 )
+ {
+ // minimal length is already >= w, so no padding (cool!)
+ res.swap(tmp);
+ }
+ else
+ { // hum.. we need to pad (it was necessarily multi-output)
+ typedef typename string_t::size_type size_type;
+ size_type i = 0;
+ while( i<tmp.size() && tmp[i] == res[i] ) // find where we should pad.
+ ++i;
+ tmp.insert(i, static_cast<size_type>( d ), oss_.fill());
+ res.swap( tmp );
+ }
+ }
+ else
+ { // okay, only one thing was printed and padded, so res is fine.
+ }
+ }
+
+ prev_state.apply_on(oss_);
+ empty_buf( oss_);
+ oss_.clear();
+} // end- put(..)
+
+
+} // local namespace
+
+
+
+
+
+template< class Ch, class Tr, class T>
+void distribute(basic_format<Ch,Tr>& self, T x)
+ // call put(x, ..) on every occurence of the current argument :
+{
+ if(self.cur_arg_ >= self.num_args_)
+ {
+ if( self.exceptions() & too_many_args_bit )
+ boost::throw_exception(too_many_args()); // too many variables have been supplied !
+ else return;
+ }
+ for(unsigned long i=0; i < self.items_.size(); ++i)
+ {
+ if(self.items_[i].argN_ == self.cur_arg_)
+ {
+ put<Ch, Tr, T> (x, self.items_[i], self.items_[i].res_, self.oss_ );
+ }
+ }
+}
+
+template<class Ch, class Tr, class T>
+basic_format<Ch, Tr>& feed(basic_format<Ch,Tr>& self, T x)
+{
+ if(self.dumped_) self.clear();
+ distribute<Ch, Tr, T> (self, x);
+ ++self.cur_arg_;
+ if(self.bound_.size() != 0)
+ {
+ while( self.cur_arg_ < self.num_args_ && self.bound_[self.cur_arg_] )
+ ++self.cur_arg_;
+ }
+
+ // this arg is finished, reset the stream's format state
+ self.state0_.apply_on(self.oss_);
+ return self;
+}
+
+
+} // namespace detail
+} // namespace io
+} // namespace boost
+
+
+#endif // BOOST_FORMAT_FEED_ARGS_HPP