// -*- 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 {
inline
void empty_buf(BOOST_IO_STD ostringstream & os) {
static const std::string emptyStr;
os.str(emptyStr);
}
void do_pad( std::string & s,
std::streamsize w,
const char c,
std::ios::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::left) {
s.append(n, c);
}
else {
s.insert(s.begin(), n, c);
}
}
} // -do_pad(..)
template<class T> inline
void put_head(BOOST_IO_STD ostream& , const T& ) {
}
template<class T> inline
void put_head( BOOST_IO_STD ostream& os, const group1<T>& x ) {
os << group_head(x.a1_); // send the first N-1 items, not the last
}
template<class T> inline
void put_last( BOOST_IO_STD ostream& os, const T& x ) {
os << x ;
}
template<class T> inline
void put_last( BOOST_IO_STD ostream& os, const group1<T>& x ) {
os << group_last(x.a1_); // this selects the last element
}
#ifndef BOOST_NO_OVERLOAD_FOR_NON_CONST
template<class T> inline
void put_head( BOOST_IO_STD ostream& , T& ) {
}
template<class T> inline
void put_last( BOOST_IO_STD ostream& os, T& x ) {
os << x ;
}
#endif
template<class T>
void put( T x,
const format_item& specs,
std::string & res,
BOOST_IO_STD ostringstream& oss_ )
{
// does the actual conversion of x, with given params, into a string
// using the *supplied* strinstream. (the stream state is important)
typedef std::string string_t;
typedef format_item format_item_t;
stream_format_state 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::fmtflags fl=oss_.flags();
const bool internal = (fl & std::ios::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 T>
void distribute(basic_format& 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<T> (x, self.items_[i], self.items_[i].res_, self.oss_ );
}
}
}
template<class T>
basic_format& feed(basic_format& self, T x)
{
if(self.dumped_) self.clear();
distribute<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
