1bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant//===----------------------------------------------------------------------===// 2bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant// 3f5256e16dfc425c1d466f6308d4026d529ce9e0bHoward Hinnant// The LLVM Compiler Infrastructure 4bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant// 5b64f8b07c104c6cc986570ac8ee0ed16a9f23976Howard Hinnant// This file is dual licensed under the MIT and the University of Illinois Open 6b64f8b07c104c6cc986570ac8ee0ed16a9f23976Howard Hinnant// Source Licenses. See LICENSE.TXT for details. 7bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant// 8bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant//===----------------------------------------------------------------------===// 9bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant 10bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant// <istream> 11bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant 12bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant// basic_istream<charT,traits>& seekg(off_type off, ios_base::seekdir dir); 13bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant 14bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant#include <istream> 15bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant#include <cassert> 16bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant 17bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnantint seekoff_called = 0; 18bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant 19bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnanttemplate <class CharT> 20bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnantstruct testbuf 21bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant : public std::basic_streambuf<CharT> 22bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant{ 23bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant typedef std::basic_string<CharT> string_type; 24bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant typedef std::basic_streambuf<CharT> base; 25bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnantprivate: 26bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant string_type str_; 27bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnantpublic: 28bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant 29bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant testbuf() {} 30bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant testbuf(const string_type& str) 31bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant : str_(str) 32bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant { 33bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant base::setg(const_cast<CharT*>(str_.data()), 34bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant const_cast<CharT*>(str_.data()), 35bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant const_cast<CharT*>(str_.data()) + str_.size()); 36bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant } 37bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant 38bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant CharT* eback() const {return base::eback();} 39bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant CharT* gptr() const {return base::gptr();} 40bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant CharT* egptr() const {return base::egptr();} 41bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnantprotected: 42bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant typename base::pos_type seekoff(typename base::off_type off, 43bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant std::ios_base::seekdir way, 44bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant std::ios_base::openmode which) 45bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant { 46bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant assert(which == std::ios_base::in); 47bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant ++seekoff_called; 48bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant return off; 49bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant } 50bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant}; 51bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant 52bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnantint main() 53bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant{ 54bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant { 55bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant testbuf<char> sb(" 123456789"); 56bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant std::istream is(&sb); 57bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant is.seekg(5, std::ios_base::cur); 58bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant assert(is.good()); 59bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant assert(seekoff_called == 1); 6076a8670ce4404429a36ea8672590da79172528c8Marshall Clow is.seekg(-1, std::ios_base::beg); 6176a8670ce4404429a36ea8672590da79172528c8Marshall Clow assert(is.fail()); 6276a8670ce4404429a36ea8672590da79172528c8Marshall Clow assert(seekoff_called == 2); 63bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant } 64bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant { 65bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant testbuf<wchar_t> sb(L" 123456789"); 66bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant std::wistream is(&sb); 67bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant is.seekg(5, std::ios_base::cur); 68bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant assert(is.good()); 6976a8670ce4404429a36ea8672590da79172528c8Marshall Clow assert(seekoff_called == 3); 7076a8670ce4404429a36ea8672590da79172528c8Marshall Clow is.seekg(-1, std::ios_base::beg); 7176a8670ce4404429a36ea8672590da79172528c8Marshall Clow assert(is.fail()); 7276a8670ce4404429a36ea8672590da79172528c8Marshall Clow assert(seekoff_called == 4); 73bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant } 74bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant} 75