underflow.pass.cpp revision b64f8b07c104c6cc986570ac8ee0ed16a9f23976 
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
20template <class CharT>
21struct 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
32int 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