//===----------------------------------------------------------------------===//
//
//                     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.
//
//===----------------------------------------------------------------------===//

// <ostream>

// template <class charT, class traits = char_traits<charT> >
//   class basic_ostream;

// operator<<(const void* val);

#include <ostream>
#include <cassert>

template <class CharT>
class testbuf
    : public std::basic_streambuf<CharT>
{
    typedef std::basic_streambuf<CharT> base;
    std::basic_string<CharT> str_;
public:
    testbuf()
    {
    }

    std::basic_string<CharT> str() const
        {return std::basic_string<CharT>(base::pbase(), base::pptr());}

protected:

    virtual typename base::int_type
        overflow(typename base::int_type __c = base::traits_type::eof())
        {
            if (__c != base::traits_type::eof())
            {
                int n = str_.size();
                str_.push_back(__c);
                str_.resize(str_.capacity());
                base::setp(const_cast<CharT*>(str_.data()),
                           const_cast<CharT*>(str_.data() + str_.size()));
                base::pbump(n+1);
            }
            return __c;
        }
};

int main()
{
    {
        std::ostream os((std::streambuf*)0);
        const void* n = 0;
        os << n;
        assert(os.bad());
        assert(os.fail());
    }
    {
        testbuf<char> sb;
        std::ostream os(&sb);
        const void* n = 0;
        os << n;
        assert(os.good());
        // %p is implementation defined.
        // On some platforms (Windows), it's a hex number without
        // any leading 0x like prefix.
        // In that format, we assume a null pointer will yield 2 '0' hex digits
        // for each 8 bits of address space.
        assert(sb.str() == "0x0" || sb.str() == "(nil)" ||
                                  sb.str() == std::string(sizeof(void*)*2,'0'));
    }
    {
        testbuf<char> sb;
        std::ostream os(&sb);
        const void* n = &sb;
        os << n;
        assert(os.good());
    }
}