std::istreambuf_iterator

template <class charT=char, class traits=char_traits<charT> >
  class istreambuf_iterator :
    public iterator<input_iterator_tag, charT,
                    typename traits::off_type, charT*, charT&>
{
public:
  typedef charT char_type;
  typedef traits traits_type;
  typedef typename traits::int_type int_type;
  typedef basic_streambuf<charT,traits> streambuf_type;
  typedef basic_istream<charT,traits> istream_type;
  class proxy {
    charT keep_; streambuf_type* sbuf_;
  public:
    proxy (charT c, streambuf_type* sbuf) : keep_(c), sbuf_(sbuf) { }
    charT operator*() {return keep_;}
  };
  istreambuf_iterator() throw() : sbuf_(0) { }
  istreambuf_iterator(istream_type& s) throw(): sbuf_(s.rdbuf()) { }
  istreambuf_iterator(streambuf_type* s) throw(): sbuf_(s) { }
  istreambuf_iterator(const proxy& p) throw(): sbuf_(p.sbuf_) { }
  charT operator*() const { return sbuf_->sgetc(); }
  istreambuf_iterator<charT,traits>& operator++() { sbuf_->sbumpc(); return *this; }
  proxy operator++(int) {return proxy(sbuf_->sbumpc(),sbuf_);}
  bool equal (istreambuf_iterator& b) const {
    if ( sbuf_==0 || *(*this)==traits::eof() ) 
    { if ( b.sbuf_==0 || *b==traits::eof() ) return true; }
    else if ( b.sbuf_!=0 && *b!= traits::eof() ) return true;
    return false;
  }
private:
  streambuf_type* sbuf_;
  
};