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>& unget(); 13bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant 14bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant#include <istream> 15bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant#include <cassert> 16bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant 17bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnanttemplate <class CharT> 18bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnantstruct testbuf 19bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant : public std::basic_streambuf<CharT> 20bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant{ 21bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant typedef std::basic_string<CharT> string_type; 22bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant typedef std::basic_streambuf<CharT> base; 23bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnantprivate: 24bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant string_type str_; 25bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnantpublic: 26bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant 27bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant testbuf() {} 28bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant testbuf(const string_type& str) 29bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant : str_(str) 30bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant { 31bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant base::setg(const_cast<CharT*>(str_.data()), 32bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant const_cast<CharT*>(str_.data()), 33bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant const_cast<CharT*>(str_.data()) + str_.size()); 34bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant } 35bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant 36bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant CharT* eback() const {return base::eback();} 37bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant CharT* gptr() const {return base::gptr();} 38bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant CharT* egptr() const {return base::egptr();} 39bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant}; 40bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant 41bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnantint main() 42bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant{ 43bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant { 44bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant testbuf<char> sb(" 123456789"); 45bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant std::istream is(&sb); 46bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant is.get(); 47bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant is.get(); 48bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant is.get(); 49bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant is.unget(); 50bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant assert(is.good()); 51bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant assert(is.gcount() == 0); 52bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant is.unget(); 53bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant assert(is.good()); 54bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant assert(is.gcount() == 0); 55bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant is.unget(); 56bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant assert(is.good()); 57bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant assert(is.gcount() == 0); 58bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant is.unget(); 59bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant assert(is.bad()); 60bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant assert(is.gcount() == 0); 61bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant } 62bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant { 63bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant testbuf<wchar_t> sb(L" 123456789"); 64bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant std::wistream is(&sb); 65bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant is.get(); 66bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant is.get(); 67bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant is.get(); 68bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant is.unget(); 69bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant assert(is.good()); 70bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant assert(is.gcount() == 0); 71bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant is.unget(); 72bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant assert(is.good()); 73bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant assert(is.gcount() == 0); 74bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant is.unget(); 75bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant assert(is.good()); 76bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant assert(is.gcount() == 0); 77bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant is.unget(); 78bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant assert(is.bad()); 79bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant assert(is.gcount() == 0); 80bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant } 81bc8d3f97eb5c958007f2713238472e0c1c8fe02Howard Hinnant} 82