boost/io/ostream_joiner.hpp

0001 /*
0002 Copyright 2019 Glen Joseph Fernandes
0003 (glenjofe@gmail.com)
0004
0005 Distributed under the Boost Software License, Version 1.0.
0006 (http://www.boost.org/LICENSE_1_0.txt)
0007 */
0008 #ifndef BOOST_IO_OSTREAM_JOINER_HPP
0009 #define BOOST_IO_OSTREAM_JOINER_HPP
0010
0011 #include <boost/config.hpp>
0012 #include <ostream>
0013 #include <string>
0014 #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
0015 #if !defined(BOOST_NO_CXX11_HDR_TYPE_TRAITS)
0016 #include <type_traits>
0017 #endif
0018 #include <utility>
0019 #endif
0020
0021 namespace boost {
0022 namespace io {
0023 namespace detail {
0024
0025 #if !defined(BOOST_NO_CXX11_ADDRESSOF)
0026 template<class T>
0027 inline T*
0028 osj_address(T& o)
0029 {
0030     return std::addressof(o);
0031 }
0032 #else
0033 template<class T>
0034 inline T*
0035 osj_address(T& obj)
0036 {
0037     return &obj;
0038 }
0039 #endif
0040
0041 } /* detail */
0042
0043 template<class Delim, class Char = char,
0044     class Traits = std::char_traits<Char> >
0045 class ostream_joiner {
0046 public:
0047     typedef Char char_type;
0048     typedef Traits traits_type;
0049     typedef std::basic_ostream<Char, Traits> ostream_type;
0050     typedef std::output_iterator_tag iterator_category;
0051     typedef void value_type;
0052     typedef void difference_type;
0053     typedef void pointer;
0054     typedef void reference;
0055
0056     ostream_joiner(ostream_type& output, const Delim& delim)
0057         : output_(detail::osj_address(output))
0058         , delim_(delim)
0059         , first_(true) { }
0060
0061 #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
0062     ostream_joiner(ostream_type& output, Delim&& delim)
0063         : output_(detail::osj_address(output))
0064         , delim_(std::move(delim))
0065         , first_(true) { }
0066 #endif
0067
0068     template<class T>
0069     ostream_joiner& operator=(const T& value) {
0070         if (!first_) {
0071             *output_ << delim_;
0072         }
0073         first_ = false;
0074         *output_ << value;
0075         return *this;
0076     }
0077
0078     ostream_joiner& operator*() BOOST_NOEXCEPT {
0079         return *this;
0080     }
0081
0082     ostream_joiner& operator++() BOOST_NOEXCEPT {
0083         return *this;
0084     }
0085
0086     ostream_joiner& operator++(int) BOOST_NOEXCEPT {
0087         return *this;
0088     }
0089
0090 private:
0091     ostream_type* output_;
0092     Delim delim_;
0093     bool first_;
0094 };
0095
0096 #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES) && \
0097     !defined(BOOST_NO_CXX11_HDR_TYPE_TRAITS)
0098 template<class Char, class Traits, class Delim>
0099 inline ostream_joiner<typename std::decay<Delim>::type, Char, Traits>
0100 make_ostream_joiner(std::basic_ostream<Char, Traits>& output, Delim&& delim)
0101 {
0102     return ostream_joiner<typename std::decay<Delim>::type, Char,
0103         Traits>(output, std::forward<Delim>(delim));
0104 }
0105 #else
0106 template<class Char, class Traits, class Delim>
0107 inline ostream_joiner<Delim, Char, Traits>
0108 make_ostream_joiner(std::basic_ostream<Char, Traits>& output,
0109     const Delim& delim)
0110 {
0111     return ostream_joiner<Delim, Char, Traits>(output, delim);
0112 }
0113 #endif
0114
0115 } /* io */
0116 } /* boost */
0117
0118 #endif