seekg_off.pass.cpp (2419B)
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=macosx10.11 11 // XFAIL: with_system_cxx_lib=macosx10.10 12 // XFAIL: with_system_cxx_lib=macosx10.9 13 14 // <istream> 15 16 // basic_istream<charT,traits>& seekg(off_type off, ios_base::seekdir dir); 17 18 #include <istream> 19 #include <cassert> 20 21 int seekoff_called = 0; 22 23 template <class CharT> 24 struct testbuf 25 : public std::basic_streambuf<CharT> 26 { 27 typedef std::basic_string<CharT> string_type; 28 typedef std::basic_streambuf<CharT> base; 29 private: 30 string_type str_; 31 public: 32 33 testbuf() {} 34 testbuf(const string_type& str) 35 : str_(str) 36 { 37 base::setg(const_cast<CharT*>(str_.data()), 38 const_cast<CharT*>(str_.data()), 39 const_cast<CharT*>(str_.data()) + str_.size()); 40 } 41 42 CharT* eback() const {return base::eback();} 43 CharT* gptr() const {return base::gptr();} 44 CharT* egptr() const {return base::egptr();} 45 protected: 46 typename base::pos_type seekoff(typename base::off_type off, 47 std::ios_base::seekdir, 48 std::ios_base::openmode which) 49 { 50 assert(which == std::ios_base::in); 51 ++seekoff_called; 52 return off; 53 } 54 }; 55 56 int main() 57 { 58 { 59 testbuf<char> sb(" 123456789"); 60 std::istream is(&sb); 61 is.seekg(5, std::ios_base::cur); 62 assert(is.good()); 63 assert(seekoff_called == 1); 64 is.seekg(-1, std::ios_base::beg); 65 assert(is.fail()); 66 assert(seekoff_called == 2); 67 } 68 { 69 testbuf<wchar_t> sb(L" 123456789"); 70 std::wistream is(&sb); 71 is.seekg(5, std::ios_base::cur); 72 assert(is.good()); 73 assert(seekoff_called == 3); 74 is.seekg(-1, std::ios_base::beg); 75 assert(is.fail()); 76 assert(seekoff_called == 4); 77 } 78 { 79 testbuf<char> sb(" 123456789"); 80 std::istream is(&sb); 81 is.setstate(std::ios_base::eofbit); 82 assert(is.eof()); 83 is.seekg(5, std::ios_base::beg); 84 assert(is.good()); 85 assert(!is.eof()); 86 } 87 }