pbackfail.pass.cpp revision f5256e16dfc425c1d466f6308d4026d529ce9e0b 
1//===----------------------------------------------------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10// <fstream>
11
12// int_type pbackfail(int_type c = traits::eof());
13
14// This test is not entirely portable
15
16#include <fstream>
17#include <cassert>
18
19template <class CharT>
20struct test_buf
21    : public std::basic_filebuf<CharT>
22{
23    typedef std::basic_filebuf<CharT>  base;
24    typedef typename base::char_type   char_type;
25    typedef typename base::int_type    int_type;
26    typedef typename base::traits_type traits_type;
27
28    char_type* eback() const {return base::eback();}
29    char_type* gptr()  const {return base::gptr();}
30    char_type* egptr() const {return base::egptr();}
31    void gbump(int n) {base::gbump(n);}
32
33    virtual int_type pbackfail(int_type c = traits_type::eof()) {return base::pbackfail(c);}
34};
35
36int main()
37{
38    {
39        test_buf<char> f;
40        assert(f.open("underflow.dat", std::ios_base::in) != 0);
41        assert(f.is_open());
42        assert(f.sbumpc() == '1');
43        assert(f.sgetc() == '2');
44        assert(f.pbackfail('a') == -1);
45    }
46    {
47        test_buf<char> f;
48        assert(f.open("underflow.dat", std::ios_base::in | std::ios_base::out) != 0);
49        assert(f.is_open());
50        assert(f.sbumpc() == '1');
51        assert(f.sgetc() == '2');
52        assert(f.pbackfail('a') == 'a');
53        assert(f.sbumpc() == 'a');
54        assert(f.sgetc() == '2');
55    }
56}
57