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      1 //===----------------------------------------------------------------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is dual licensed under the MIT and the University of Illinois Open
      6 // Source Licenses. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 
     10 // <ostream>
     11 
     12 // template <class charT, class traits = char_traits<charT> >
     13 //   class basic_ostream;
     14 
     15 // operator<<(long val);
     16 
     17 #include <ostream>
     18 #include <cassert>
     19 
     20 template <class CharT>
     21 class testbuf
     22     : public std::basic_streambuf<CharT>
     23 {
     24     typedef std::basic_streambuf<CharT> base;
     25     std::basic_string<CharT> str_;
     26 public:
     27     testbuf()
     28     {
     29     }
     30 
     31     std::basic_string<CharT> str() const
     32         {return std::basic_string<CharT>(base::pbase(), base::pptr());}
     33 
     34 protected:
     35 
     36     virtual typename base::int_type
     37         overflow(typename base::int_type ch = base::traits_type::eof())
     38         {
     39             if (ch != base::traits_type::eof())
     40             {
     41                 int n = static_cast<int>(str_.size());
     42                 str_.push_back(static_cast<CharT>(ch));
     43                 str_.resize(str_.capacity());
     44                 base::setp(const_cast<CharT*>(str_.data()),
     45                            const_cast<CharT*>(str_.data() + str_.size()));
     46                 base::pbump(n+1);
     47             }
     48             return ch;
     49         }
     50 };
     51 
     52 int main()
     53 {
     54     {
     55         std::ostream os((std::streambuf*)0);
     56         long n = 0;
     57         os << n;
     58         assert(os.bad());
     59         assert(os.fail());
     60     }
     61     {
     62         testbuf<char> sb;
     63         std::ostream os(&sb);
     64         long n = 0;
     65         os << n;
     66         assert(sb.str() == "0");
     67     }
     68     {
     69         testbuf<char> sb;
     70         std::ostream os(&sb);
     71         long n = -10;
     72         os << n;
     73         assert(sb.str() == "-10");
     74     }
     75     {
     76         testbuf<char> sb;
     77         std::ostream os(&sb);
     78         hex(os);
     79         long n = 0xfffffff6;
     80         os << n;
     81         assert(sb.str() == "fffffff6");
     82     }
     83 }
     84