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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 // <sstream>
     11 
     12 // template <class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >
     13 // class basic_stringbuf
     14 
     15 // int_type underflow();
     16 
     17 #include <sstream>
     18 #include <cassert>
     19 
     20 template <class CharT>
     21 struct testbuf
     22     : public std::basic_stringbuf<CharT>
     23 {
     24     typedef std::basic_stringbuf<CharT> base;
     25     explicit testbuf(const std::basic_string<CharT>& str)
     26         : base(str) {}
     27 
     28     typename base::int_type underflow() {return base::underflow();}
     29     void pbump(int n) {base::pbump(n);}
     30 };
     31 
     32 int main()
     33 {
     34     {
     35         testbuf<char> sb("123");
     36         sb.pbump(3);
     37         assert(sb.underflow() == '1');
     38         assert(sb.underflow() == '1');
     39         assert(sb.snextc() == '2');
     40         assert(sb.underflow() == '2');
     41         assert(sb.underflow() == '2');
     42         assert(sb.snextc() == '3');
     43         assert(sb.underflow() == '3');
     44         assert(sb.underflow() == '3');
     45         assert(sb.snextc() == std::char_traits<char>::eof());
     46         assert(sb.underflow() == std::char_traits<char>::eof());
     47         assert(sb.underflow() == std::char_traits<char>::eof());
     48         sb.sputc('4');
     49         assert(sb.underflow() == '4');
     50         assert(sb.underflow() == '4');
     51     }
     52     {
     53         testbuf<wchar_t> sb(L"123");
     54         sb.pbump(3);
     55         assert(sb.underflow() == L'1');
     56         assert(sb.underflow() == L'1');
     57         assert(sb.snextc() == L'2');
     58         assert(sb.underflow() == L'2');
     59         assert(sb.underflow() == L'2');
     60         assert(sb.snextc() == L'3');
     61         assert(sb.underflow() == L'3');
     62         assert(sb.underflow() == L'3');
     63         assert(sb.snextc() == std::char_traits<wchar_t>::eof());
     64         assert(sb.underflow() == std::char_traits<wchar_t>::eof());
     65         assert(sb.underflow() == std::char_traits<wchar_t>::eof());
     66         sb.sputc(L'4');
     67         assert(sb.underflow() == L'4');
     68         assert(sb.underflow() == L'4');
     69     }
     70 }
     71