pbackfail.pass.cpp (1972B)
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 // <fstream> 11 12 // int_type pbackfail(int_type c = traits::eof()); 13 14 #include <fstream> 15 #include <cassert> 16 17 #include "test_macros.h" 18 19 template <class CharT> 20 struct test_buf 21 : public std::basic_filebuf<CharT> 22 { 23 typedef std::basic_filebuf<CharT> base; 24 typedef typename base::char_type char_type; 25 typedef typename base::int_type int_type; 26 typedef typename base::traits_type traits_type; 27 28 char_type* eback() const {return base::eback();} 29 char_type* gptr() const {return base::gptr();} 30 char_type* egptr() const {return base::egptr();} 31 void gbump(int n) {base::gbump(n);} 32 33 virtual int_type pbackfail(int_type c = traits_type::eof()) {return base::pbackfail(c);} 34 }; 35 36 int main() 37 { 38 { 39 test_buf<char> f; 40 assert(f.open("underflow.dat", std::ios_base::in) != 0); 41 assert(f.is_open()); 42 assert(f.sbumpc() == '1'); 43 assert(f.sgetc() == '2'); 44 typename test_buf<char>::int_type pbackResult = f.pbackfail('a'); 45 LIBCPP_ASSERT(pbackResult == -1); 46 if (pbackResult != -1) { 47 assert(f.sbumpc() == 'a'); 48 assert(f.sgetc() == '2'); 49 } 50 } 51 { 52 test_buf<char> f; 53 assert(f.open("underflow.dat", std::ios_base::in | std::ios_base::out) != 0); 54 assert(f.is_open()); 55 assert(f.sbumpc() == '1'); 56 assert(f.sgetc() == '2'); 57 typename test_buf<char>::int_type pbackResult = f.pbackfail('a'); 58 LIBCPP_ASSERT(pbackResult == 'a'); 59 if (pbackResult != -1) { 60 assert(f.sbumpc() == 'a'); 61 assert(f.sgetc() == '2'); 62 } 63 } 64 }