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 // <istream> 11 12 // int_type peek(); 13 14 #include <istream> 15 #include <cassert> 16 17 template <class CharT> 18 struct testbuf 19 : public std::basic_streambuf<CharT> 20 { 21 typedef std::basic_string<CharT> string_type; 22 typedef std::basic_streambuf<CharT> base; 23 private: 24 string_type str_; 25 public: 26 27 testbuf() {} 28 testbuf(const string_type& str) 29 : str_(str) 30 { 31 base::setg(const_cast<CharT*>(str_.data()), 32 const_cast<CharT*>(str_.data()), 33 const_cast<CharT*>(str_.data()) + str_.size()); 34 } 35 36 CharT* eback() const {return base::eback();} 37 CharT* gptr() const {return base::gptr();} 38 CharT* egptr() const {return base::egptr();} 39 }; 40 41 int main() 42 { 43 { 44 testbuf<char> sb(" 1\n2345\n6"); 45 std::istream is(&sb); 46 assert(is.peek() == ' '); 47 assert(!is.eof()); 48 assert(!is.fail()); 49 assert(is.gcount() == 0); 50 is.get(); 51 assert(is.peek() == '1'); 52 assert(!is.eof()); 53 assert(!is.fail()); 54 assert(is.gcount() == 0); 55 } 56 { 57 testbuf<wchar_t> sb(L" 1\n2345\n6"); 58 std::wistream is(&sb); 59 assert(is.peek() == L' '); 60 assert(!is.eof()); 61 assert(!is.fail()); 62 assert(is.gcount() == 0); 63 is.get(); 64 assert(is.peek() == L'1'); 65 assert(!is.eof()); 66 assert(!is.fail()); 67 assert(is.gcount() == 0); 68 } 69 } 70
