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     {  // sanity check
40     testbuf<char> tb("");
41     tb.pbackfail();
42     }
43     {
44         testbuf<char> sb("123", std::ios_base::in);
45         assert(sb.sgetc() == '1');
46         assert(sb.snextc() == '2');
47         assert(sb.snextc() == '3');
48         assert(sb.sgetc() == '3');
49         assert(sb.snextc() == std::char_traits<char>::eof());
50         assert(sb.pbackfail('3') == '3');
51         assert(sb.pbackfail('3') == std::char_traits<char>::eof());
52         assert(sb.pbackfail('2') == '2');
53         assert(sb.pbackfail(std::char_traits<char>::eof()) != std::char_traits<char>::eof());
54         assert(sb.pbackfail(std::char_traits<char>::eof()) == std::char_traits<char>::eof());
55         assert(sb.str() == "123");
56     }
57     {
58         testbuf<char> sb("123");
59         assert(sb.sgetc() == '1');
60         assert(sb.snextc() == '2');
61         assert(sb.snextc() == '3');
62         assert(sb.sgetc() == '3');
63         assert(sb.snextc() == std::char_traits<char>::eof());
64         assert(sb.pbackfail('3') == '3');
65         assert(sb.pbackfail('3') == '3');
66         assert(sb.pbackfail(std::char_traits<char>::eof()) != std::char_traits<char>::eof());
67         assert(sb.pbackfail(std::char_traits<char>::eof()) == std::char_traits<char>::eof());
68         assert(sb.str() == "133");
69     }
70     {
71         testbuf<wchar_t> sb(L"123", std::ios_base::in);
72         assert(sb.sgetc() == L'1');
73         assert(sb.snextc() == L'2');
74         assert(sb.snextc() == L'3');
75         assert(sb.sgetc() == L'3');
76         assert(sb.snextc() == std::char_traits<wchar_t>::eof());
77         assert(sb.pbackfail(L'3') == L'3');
78         assert(sb.pbackfail(L'3') == std::char_traits<wchar_t>::eof());
79         assert(sb.pbackfail(L'2') == L'2');
80         assert(sb.pbackfail(std::char_traits<wchar_t>::eof()) != std::char_traits<wchar_t>::eof());
81         assert(sb.pbackfail(std::char_traits<wchar_t>::eof()) == std::char_traits<wchar_t>::eof());
82         assert(sb.str() == L"123");
83     }
84     {
85         testbuf<wchar_t> sb(L"123");
86         assert(sb.sgetc() == L'1');
87         assert(sb.snextc() == L'2');
88         assert(sb.snextc() == L'3');
89         assert(sb.sgetc() == L'3');
90         assert(sb.snextc() == std::char_traits<wchar_t>::eof());
91         assert(sb.pbackfail(L'3') == L'3');
92         assert(sb.pbackfail(L'3') == L'3');
93         assert(sb.pbackfail(std::char_traits<wchar_t>::eof()) != std::char_traits<wchar_t>::eof());
94         assert(sb.pbackfail(std::char_traits<wchar_t>::eof()) == std::char_traits<wchar_t>::eof());
95         assert(sb.str() == L"133");
96     }
97 
98   return 0;
99 }
100