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//===----------------------------------------------------------------------===//
//
// 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>& putback(char_type c);
#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.putback('a');
assert(is.bad());
assert(is.gcount() == 0);
is.clear();
is.putback('2');
assert(is.good());
assert(is.gcount() == 0);
is.putback('1');
assert(is.good());
assert(is.gcount() == 0);
is.putback(' ');
assert(is.good());
assert(is.gcount() == 0);
is.putback(' ');
assert(is.bad());
assert(is.gcount() == 0);
}
{
testbuf<wchar_t> sb(L" 123456789");
std::wistream is(&sb);
is.get();
is.get();
is.get();
is.putback(L'a');
assert(is.bad());
assert(is.gcount() == 0);
is.clear();
is.putback(L'2');
assert(is.good());
assert(is.gcount() == 0);
is.putback(L'1');
assert(is.good());
assert(is.gcount() == 0);
is.putback(L' ');
assert(is.good());
assert(is.gcount() == 0);
is.putback(L' ');
assert(is.bad());
assert(is.gcount() == 0);
}
}
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