libcxx/test/std/input.output/string.streams/stringbuf/stringbuf.virtuals/pbackfail.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // <sstream>
  10
  11 // template <class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >
  12 // class basic_stringbuf
  13
  14 // int_type pbackfail(int_type c = traits::eof());
  15
  16 #include <sstream>
  17 #include <cassert>
  18
  19 #include "test_macros.h"
  20
  21 template <class CharT>
  22 struct testbuf
  23     : public std::basic_stringbuf<CharT>
  24 {
  25     typedef std::basic_stringbuf<CharT> base;
  26     explicit testbuf(const std::basic_string<CharT>& str,
  27                      std::ios_base::openmode which = std::ios_base::in | std::ios_base::out)
  28         : base(str, which) {}
  29
  30     typename base::int_type
  31         pbackfail(typename base::int_type c = base::traits_type::eof())
  32         {return base::pbackfail(c);}
  33
  34     void pbump(int n) {base::pbump(n);}
  35 };
  36
  37 int main(int, char**)
  38 {
  39     // check pbackfail
  40     {
  41         testbuf<char> tb("");
  42         tb.pbackfail();
  43     }
  44     {
  45         testbuf<char> sb("123", std::ios_base::in);
  46         assert(sb.sgetc() == '1');
  47         assert(sb.snextc() == '2');
  48         assert(sb.snextc() == '3');
  49         assert(sb.sgetc() == '3');
  50         assert(sb.snextc() == std::char_traits<char>::eof());
  51         assert(sb.pbackfail('3') == '3');
  52         assert(sb.pbackfail('3') == std::char_traits<char>::eof());
  53         assert(sb.pbackfail('2') == '2');
  54         assert(sb.pbackfail(std::char_traits<char>::eof()) != std::char_traits<char>::eof());
  55         assert(sb.pbackfail(std::char_traits<char>::eof()) == std::char_traits<char>::eof());
  56         assert(sb.str() == "123");
  57     }
  58     {
  59         testbuf<char> sb("123");
  60         assert(sb.sgetc() == '1');
  61         assert(sb.snextc() == '2');
  62         assert(sb.snextc() == '3');
  63         assert(sb.sgetc() == '3');
  64         assert(sb.snextc() == std::char_traits<char>::eof());
  65         assert(sb.pbackfail('3') == '3');
  66         assert(sb.pbackfail('3') == '3');
  67         assert(sb.pbackfail(std::char_traits<char>::eof()) != std::char_traits<char>::eof());
  68         assert(sb.pbackfail(std::char_traits<char>::eof()) == std::char_traits<char>::eof());
  69         assert(sb.str() == "133");
  70     }
  71 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
  72     {
  73         testbuf<wchar_t> sb(L"123", std::ios_base::in);
  74         assert(sb.sgetc() == L'1');
  75         assert(sb.snextc() == L'2');
  76         assert(sb.snextc() == L'3');
  77         assert(sb.sgetc() == L'3');
  78         assert(sb.snextc() == std::char_traits<wchar_t>::eof());
  79         assert(sb.pbackfail(L'3') == L'3');
  80         assert(sb.pbackfail(L'3') == std::char_traits<wchar_t>::eof());
  81         assert(sb.pbackfail(L'2') == L'2');
  82         assert(sb.pbackfail(std::char_traits<wchar_t>::eof()) != std::char_traits<wchar_t>::eof());
  83         assert(sb.pbackfail(std::char_traits<wchar_t>::eof()) == std::char_traits<wchar_t>::eof());
  84         assert(sb.str() == L"123");
  85     }
  86     {
  87         testbuf<wchar_t> sb(L"123");
  88         assert(sb.sgetc() == L'1');
  89         assert(sb.snextc() == L'2');
  90         assert(sb.snextc() == L'3');
  91         assert(sb.sgetc() == L'3');
  92         assert(sb.snextc() == std::char_traits<wchar_t>::eof());
  93         assert(sb.pbackfail(L'3') == L'3');
  94         assert(sb.pbackfail(L'3') == L'3');
  95         assert(sb.pbackfail(std::char_traits<wchar_t>::eof()) != std::char_traits<wchar_t>::eof());
  96         assert(sb.pbackfail(std::char_traits<wchar_t>::eof()) == std::char_traits<wchar_t>::eof());
  97         assert(sb.str() == L"133");
  98     }
  99 #endif
 100
 101   return 0;
 102 }