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// XFAIL: with_system_cxx_lib=macosx10.12
11// XFAIL: with_system_cxx_lib=macosx10.11
12// XFAIL: with_system_cxx_lib=macosx10.10
13// XFAIL: with_system_cxx_lib=macosx10.9
14// XFAIL: with_system_cxx_lib=macosx10.7
15// XFAIL: with_system_cxx_lib=macosx10.8
16
17// <istream>
18
19// basic_istream<charT,traits>& seekg(off_type off, ios_base::seekdir dir);
20
21#include <istream>
22#include <cassert>
23
24int seekoff_called = 0;
25
26template <class CharT>
27struct testbuf
28    : public std::basic_streambuf<CharT>
29{
30    typedef std::basic_string<CharT> string_type;
31    typedef std::basic_streambuf<CharT> base;
32private:
33    string_type str_;
34public:
35
36    testbuf() {}
37    testbuf(const string_type& str)
38        : str_(str)
39    {
40        base::setg(const_cast<CharT*>(str_.data()),
41                   const_cast<CharT*>(str_.data()),
42                   const_cast<CharT*>(str_.data()) + str_.size());
43    }
44
45    CharT* eback() const {return base::eback();}
46    CharT* gptr() const {return base::gptr();}
47    CharT* egptr() const {return base::egptr();}
48protected:
49    typename base::pos_type seekoff(typename base::off_type off,
50                                    std::ios_base::seekdir,
51                                    std::ios_base::openmode which)
52    {
53        assert(which == std::ios_base::in);
54        ++seekoff_called;
55        return off;
56    }
57};
58
59int main()
60{
61    {
62        testbuf<char> sb(" 123456789");
63        std::istream is(&sb);
64        is.seekg(5, std::ios_base::cur);
65        assert(is.good());
66        assert(seekoff_called == 1);
67        is.seekg(-1, std::ios_base::beg);
68        assert(is.fail());
69        assert(seekoff_called == 2);
70    }
71    {
72        testbuf<wchar_t> sb(L" 123456789");
73        std::wistream is(&sb);
74        is.seekg(5, std::ios_base::cur);
75        assert(is.good());
76        assert(seekoff_called == 3);
77        is.seekg(-1, std::ios_base::beg);
78        assert(is.fail());
79        assert(seekoff_called == 4);
80    }
81    {
82        testbuf<char> sb(" 123456789");
83        std::istream is(&sb);
84        is.setstate(std::ios_base::eofbit);
85        assert(is.eof());
86        is.seekg(5, std::ios_base::beg);
87        assert(is.good());
88        assert(!is.eof());
89    }
90}
91