82 lines
2.0 KiB
C++
82 lines
2.0 KiB
C++
//===----------------------------------------------------------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is dual licensed under the MIT and the University of Illinois Open
|
|
// Source Licenses. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
// <istream>
|
|
|
|
// basic_istream<charT,traits>& unget();
|
|
|
|
#include <istream>
|
|
#include <cassert>
|
|
|
|
template <class CharT>
|
|
struct testbuf
|
|
: public std::basic_streambuf<CharT>
|
|
{
|
|
typedef std::basic_string<CharT> string_type;
|
|
typedef std::basic_streambuf<CharT> base;
|
|
private:
|
|
string_type str_;
|
|
public:
|
|
|
|
testbuf() {}
|
|
testbuf(const string_type& str)
|
|
: str_(str)
|
|
{
|
|
base::setg(const_cast<CharT*>(str_.data()),
|
|
const_cast<CharT*>(str_.data()),
|
|
const_cast<CharT*>(str_.data()) + str_.size());
|
|
}
|
|
|
|
CharT* eback() const {return base::eback();}
|
|
CharT* gptr() const {return base::gptr();}
|
|
CharT* egptr() const {return base::egptr();}
|
|
};
|
|
|
|
int main()
|
|
{
|
|
{
|
|
testbuf<char> sb(" 123456789");
|
|
std::istream is(&sb);
|
|
is.get();
|
|
is.get();
|
|
is.get();
|
|
is.unget();
|
|
assert(is.good());
|
|
assert(is.gcount() == 0);
|
|
is.unget();
|
|
assert(is.good());
|
|
assert(is.gcount() == 0);
|
|
is.unget();
|
|
assert(is.good());
|
|
assert(is.gcount() == 0);
|
|
is.unget();
|
|
assert(is.bad());
|
|
assert(is.gcount() == 0);
|
|
}
|
|
{
|
|
testbuf<wchar_t> sb(L" 123456789");
|
|
std::wistream is(&sb);
|
|
is.get();
|
|
is.get();
|
|
is.get();
|
|
is.unget();
|
|
assert(is.good());
|
|
assert(is.gcount() == 0);
|
|
is.unget();
|
|
assert(is.good());
|
|
assert(is.gcount() == 0);
|
|
is.unget();
|
|
assert(is.good());
|
|
assert(is.gcount() == 0);
|
|
is.unget();
|
|
assert(is.bad());
|
|
assert(is.gcount() == 0);
|
|
}
|
|
}
|