Add nullstream

include/boost/io/nullstream.hpp

@@ -0,0 +1,57 @@
+/*
+Copyright 2021 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+*/
+#ifndef BOOST_IO_NULLSTREAM_HPP
+#define BOOST_IO_NULLSTREAM_HPP
+
+#include <boost/config.hpp>
+#include <ostream>
+#include <streambuf>
+
+namespace boost {
+namespace io {
+
+template<class CharT, class Traits = std::char_traits<CharT> >
+class basic_nullbuf
+    : public std::basic_streambuf<CharT, Traits> {
+protected:
+    typename Traits::int_type overflow(typename Traits::int_type c)
+        BOOST_OVERRIDE {
+        return Traits::not_eof(c);
+    }
+
+    std::streamsize xsputn(const CharT*, std::streamsize n) BOOST_OVERRIDE {
+        return n;
+    }
+};
+
+namespace detail {
+
+template<class CharT, class Traits>
+struct nullbuf {
+    boost::io::basic_nullbuf<CharT, Traits> buf;
+};
+
+} /* detail */
+
+template<class CharT, class Traits = std::char_traits<CharT> >
+class basic_onullstream
+    : detail::nullbuf<CharT, Traits>
+    , public std::basic_ostream<CharT, Traits> {
+public:
+    basic_onullstream()
+        : std::basic_ostream<CharT, Traits>(&(detail::nullbuf<CharT,
+             Traits>::buf)) { }
+};
+
+typedef basic_onullstream<char> onullstream;
+typedef basic_onullstream<wchar_t> wonullstream;
+
+} /* io */
+} /* boost */
+
+#endif

test/Jamfile

@@ -17,3 +17,4 @@ run quoted_fill_test.cpp ;
 run ostream_joiner_test.cpp ;
 run make_ostream_joiner_test.cpp ;
 run ostream_put_test.cpp ;
+run nullstream_test.cpp ;

test/nullstream_test.cpp

@@ -0,0 +1,28 @@
+/*
+Copyright 2021 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+*/
+#include <boost/io/nullstream.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+int main()
+{
+    {
+        boost::io::onullstream s;
+        s << "abc";
+        s << 100;
+        s << std::endl;
+        BOOST_TEST(s);
+    }
+    {
+        boost::io::wonullstream s;
+        s << L"abc";
+        s << 100;
+        s << std::endl;
+        BOOST_TEST(s);
+    }
+    return boost::report_errors();
+}