song list: get rid of boost::zip_iterator and improve {Const,}SongIterator

src/Makefile.am

@@ -59,6 +59,7 @@ ncmpcpp_LDFLAGS = $(all_libraries)
 noinst_HEADERS = \
 	helpers/song_iterator_maker.h \
 	utility/comparators.h \
+	utility/const.h \
 	utility/conversion.h \
 	utility/functional.h \
 	utility/html.h \

src/actions.cpp

@@ -80,9 +80,9 @@ std::vector<std::shared_ptr<Actions::BaseAction>> AvailableActions;
 
 void populateActions();
 
-bool scrollTagCanBeRun(NC::List *&list, SongList *&songs);
-void scrollTagUpRun(NC::List *list, SongList *songs, MPD::Song::GetFunction get);
-void scrollTagDownRun(NC::List *list, SongList *songs, MPD::Song::GetFunction get);
+bool scrollTagCanBeRun(NC::List *&list, const SongList *&songs);
+void scrollTagUpRun(NC::List *list, const SongList *songs, MPD::Song::GetFunction get);
+void scrollTagDownRun(NC::List *list, const SongList *songs, MPD::Song::GetFunction get);
 
 void seek();
 void findItem(const SearchDirection direction);
@@ -1783,28 +1783,25 @@ bool SelectAlbum::canBeRun()
 void SelectAlbum::run()
 {
 	const auto front = m_songs->beginS(), current = m_songs->currentS(), end = m_songs->endS();
-	auto *s = current->get<Bit::Song>();
-	if (s == nullptr)
+	if (current->song() == nullptr)
 		return;
 	auto get = &MPD::Song::getAlbum;
-	const std::string tag = s->getTags(get);
+	const std::string tag = current->song()->getTags(get);
 	// go up
 	for (auto it = current; it != front;)
 	{
 		--it;
-		s = it->get<Bit::Song>();
-		if (s == nullptr || s->getTags(get) != tag)
+		if (it->song() == nullptr || it->song()->getTags(get) != tag)
 			break;
-		it->get<Bit::Properties>().setSelected(true);
+		it->properties().setSelected(true);
 	}
 	// go down
 	for (auto it = current;;)
 	{
-		it->get<Bit::Properties>().setSelected(true);
+		it->properties().setSelected(true);
 		if (++it == end)
 			break;
-		s = it->get<Bit::Song>();
-		if (s == nullptr || s->getTags(get) != tag)
+		if (it->song() == nullptr || it->song()->getTags(get) != tag)
 			break;
 	}
 	Statusbar::print("Album around cursor position selected");
@@ -2809,7 +2806,7 @@ void populateActions()
 	}
 }
 
-bool scrollTagCanBeRun(NC::List *&list, SongList *&songs)
+bool scrollTagCanBeRun(NC::List *&list, const SongList *&songs)
 {
 	auto w = myScreen->activeWindow();
 	if (list != static_cast<void *>(w))
@@ -2820,36 +2817,34 @@ bool scrollTagCanBeRun(NC::List *&list, SongList *&songs)
 	    && songs != nullptr;
 }
 
-void scrollTagUpRun(NC::List *list, SongList *songs, MPD::Song::GetFunction get)
+void scrollTagUpRun(NC::List *list, const SongList *songs, MPD::Song::GetFunction get)
 {
 	const auto front = songs->beginS();
 	auto it = songs->currentS();
-	if (auto *s = it->get<Bit::Song>())
+	if (it->song() != nullptr)
 	{
-		const std::string tag = s->getTags(get);
+		const std::string tag = it->song()->getTags(get);
 		while (it != front)
 		{
 			--it;
-			s = it->get<Bit::Song>();
-			if (s == nullptr || s->getTags(get) != tag)
+			if (it->song() == nullptr || it->song()->getTags(get) != tag)
 				break;
 		}
 		list->highlight(it-front);
 	}
 }
 
-void scrollTagDownRun(NC::List *list, SongList *songs, MPD::Song::GetFunction get)
+void scrollTagDownRun(NC::List *list, const SongList *songs, MPD::Song::GetFunction get)
 {
 	const auto front = songs->beginS(), back = --songs->endS();
 	auto it = songs->currentS();
-	if (auto *s = it->get<Bit::Song>())
+	if (it->song() != nullptr)
 	{
-		const std::string tag = s->getTags(get);
+		const std::string tag = it->song()->getTags(get);
 		while (it != back)
 		{
 			++it;
-			s = it->get<Bit::Song>();
-			if (s == nullptr || s->getTags(get) != tag)
+			if (it->song() == nullptr || it->song()->getTags(get) != tag)
 				break;
 		}
 		list->highlight(it-front);
@@ -2882,7 +2877,8 @@ void seek()
 	// can be run and one of them is of the given type. This will still not work
 	// in some contrived cases, but allows for more flexibility than accepting
 	// single actions only.
-	auto hasRunnableAction = [](BindingsConfiguration::BindingIteratorPair &bindings, Actions::Type type) {
+	auto hasRunnableAction = [](BindingsConfiguration::BindingIteratorPair &bindings,
+	                            Actions::Type type) {
 		bool success = false;
 		for (auto binding = bindings.first; binding != bindings.second; ++binding)
 		{

src/actions.h

@@ -280,7 +280,7 @@ private:
 	virtual void run() override;
 
 	NC::List *m_list;
-	SongList *m_songs;
+	const SongList *m_songs;
 };
 
 struct ScrollUpAlbum: BaseAction
@@ -292,7 +292,7 @@ private:
 	virtual void run() override;
 
 	NC::List *m_list;
-	SongList *m_songs;
+	const SongList *m_songs;
 };
 
 struct ScrollDownArtist: BaseAction
@@ -304,7 +304,7 @@ private:
 	virtual void run() override;
 
 	NC::List *m_list;
-	SongList *m_songs;
+	const SongList *m_songs;
 };
 
 struct ScrollDownAlbum: BaseAction
@@ -316,7 +316,7 @@ private:
 	virtual void run() override;
 
 	NC::List *m_list;
-	SongList *m_songs;
+	const SongList *m_songs;
 };
 
 struct PageUp: BaseAction

src/browser.cpp

@@ -70,54 +70,53 @@ void clearDirectory(const std::string &directory);
 std::string itemToString(const MPD::Item &item);
 bool browserEntryMatcher(const Regex::Regex &rx, const MPD::Item &item, bool filter);
 
-template <bool Const>
-struct SongExtractor
-{
-	typedef SongExtractor type;
-
-	typedef typename NC::Menu<MPD::Item>::Item MenuItem;
-	typedef typename std::conditional<Const, const MenuItem, MenuItem>::type Item;
-	typedef typename std::conditional<Const, const MPD::Song, MPD::Song>::type Song;
-
-	Song *operator()(Item &item) const
-	{
-		Song *ptr = nullptr;
-		if (item.value().type() == MPD::Item::Type::Song)
-			ptr = const_cast<Song *>(&item.value().song());
-		return ptr;
-	}
-};
-
 }
 
+template <>
+struct SongPropertiesExtractor<MPD::Item>
+{
+	template <typename ItemT>
+	auto &operator()(ItemT &item) const
+	{
+		auto s = item.value().type() == MPD::Item::Type::Song
+			? &item.value().song()
+			: nullptr;
+		m_cache.assign(&item.properties(), s);
+		return m_cache;
+	}
+
+private:
+	mutable SongProperties m_cache;
+};
+
 SongIterator BrowserWindow::currentS()
 {
-	return makeSongIterator_<MPD::Item>(current(), SongExtractor<false>());
+	return makeSongIterator(current());
 }
 
 ConstSongIterator BrowserWindow::currentS() const
 {
-	return makeConstSongIterator_<MPD::Item>(current(), SongExtractor<true>());
+	return makeConstSongIterator(current());
 }
 
 SongIterator BrowserWindow::beginS()
 {
-	return makeSongIterator_<MPD::Item>(begin(), SongExtractor<false>());
+	return makeSongIterator(begin());
 }
 
 ConstSongIterator BrowserWindow::beginS() const
 {
-	return makeConstSongIterator_<MPD::Item>(begin(), SongExtractor<true>());
+	return makeConstSongIterator(begin());
 }
 
 SongIterator BrowserWindow::endS()
 {
-	return makeSongIterator_<MPD::Item>(end(), SongExtractor<false>());
+	return makeSongIterator(end());
 }
 
 ConstSongIterator BrowserWindow::endS() const
 {
-	return makeConstSongIterator_<MPD::Item>(end(), SongExtractor<true>());
+	return makeConstSongIterator(end());
 }
 
 std::vector<MPD::Song> BrowserWindow::getSelectedSongs()

src/display.cpp

@@ -87,8 +87,7 @@ void setProperties(NC::Menu<T> &menu, const MPD::Song &s, const SongList &list,
 		auto next = list.beginS() + drawn_pos + 1;
 		if (next != list.endS())
 		{
-			auto next_s = next->get<Bit::Song>();
-			if (next_s != nullptr && next_s->getAlbum() != s.getAlbum())
+			if (next->song() != nullptr && next->song()->getAlbum() != s.getAlbum())
 				separate_albums = true;
 		}
 	}

src/helpers.cpp

@@ -35,7 +35,7 @@ const MPD::Song *currentSong(const BaseScreen *screen)
 	{
 		const auto it = list->currentS();
 		if (it != list->endS())
-			ptr = it->get<Bit::Song>();
+			ptr = it->song();
 	}
 	return ptr;
 }

src/helpers.h

@@ -387,12 +387,10 @@ template <typename ListT>
 void markSongsInPlaylist(ListT &list)
 {
 	ScopedUnfilteredMenu<typename ListT::Item::Type> sunfilter(ReapplyFilter::No, list);
-	MPD::Song *s;
 	for (auto &p : static_cast<SongList &>(list))
 	{
-		s = p.get<Bit::Song>();
-		if (s != nullptr)
-			p.get<Bit::Properties>().setBold(myPlaylist->checkForSong(*s));
+		if (p.song() != nullptr)
+			p.properties().setBold(myPlaylist->checkForSong(*p.song()));
 	}
 }
 

src/helpers/song_iterator_maker.h

@@ -22,26 +22,48 @@
 #define NCMPCPP_HELPERS_SONG_ITERATOR_MAKER_H
 
 #include <boost/iterator/transform_iterator.hpp>
-#include <boost/iterator/zip_iterator.hpp>
 #include "menu.h"
 #include "song_list.h"
 
-template <typename ItemT, typename TransformT>
-SongIterator makeSongIterator_(typename NC::Menu<ItemT>::Iterator it, TransformT &&map)
+template <typename SongT>
+struct SongPropertiesExtractor
 {
-	return SongIterator(boost::make_zip_iterator(boost::make_tuple(
-		typename NC::Menu<ItemT>::PropertiesIterator(it),
-		boost::make_transform_iterator(it, std::forward<TransformT>(map))
-	)));
+	template <typename ItemT>
+	auto &operator()(ItemT &item) const
+	{
+		return m_cache.assign(&item.properties(), &item.value());
+	}
+
+private:
+	mutable SongProperties m_cache;
+};
+
+template <typename IteratorT>
+SongIterator makeSongIterator(IteratorT it)
+{
+	typedef SongPropertiesExtractor<
+		typename IteratorT::value_type::Type
+		> Extractor;
+	static_assert(
+		std::is_convertible<
+		  typename std::result_of<Extractor(typename IteratorT::reference)>::type,
+		  SongProperties &
+		>::value, "invalid result type of SongPropertiesExtractor");
+	return SongIterator(boost::make_transform_iterator(it, Extractor{}));
 }
 
-template <typename ItemT, typename TransformT>
-ConstSongIterator makeConstSongIterator_(typename NC::Menu<ItemT>::ConstIterator it, TransformT &&map)
+template <typename ConstIteratorT>
+ConstSongIterator makeConstSongIterator(ConstIteratorT it)
 {
-	return ConstSongIterator(boost::make_zip_iterator(boost::make_tuple(
-		typename NC::Menu<ItemT>::ConstPropertiesIterator(it),
-		boost::make_transform_iterator(it, std::forward<TransformT>(map))
-	)));
+	typedef SongPropertiesExtractor<
+		typename ConstIteratorT::value_type::Type
+		> Extractor;
+	static_assert(
+		std::is_convertible<
+		  typename std::result_of<Extractor(typename ConstIteratorT::reference)>::type,
+		  const SongProperties &
+		>::value, "invalid result type of SongPropertiesExtractor");
+	return ConstSongIterator(boost::make_transform_iterator(it, Extractor{}));
 }
 
 #endif // NCMPCPP_HELPERS_SONG_ITERATOR_MAKER_H

src/menu.h

@@ -29,6 +29,7 @@
 #include <memory>
 #include <set>
 
+#include "utility/const.h"
 #include "strbuffer.h"
 #include "window.h"
 
@@ -197,8 +198,6 @@ struct Menu: Window, List
 		}
 
 	private:
-		enum class Const { Yes, No };
-
 		template <Const const_>
 		struct ExtractProperties
 		{
@@ -254,19 +253,19 @@ struct Menu: Window, List
 	typedef std::reverse_iterator<ConstIterator> ConstReverseIterator;
 	
 	typedef boost::transform_iterator<
-		typename Item::template ExtractValue<Item::Const::No>,
+		typename Item::template ExtractValue<Const::No>,
 		Iterator> ValueIterator;
 	typedef boost::transform_iterator<
-		typename Item::template ExtractValue<Item::Const::Yes>,
+		typename Item::template ExtractValue<Const::Yes>,
 		ConstIterator> ConstValueIterator;
 	typedef std::reverse_iterator<ValueIterator> ReverseValueIterator;
 	typedef std::reverse_iterator<ConstValueIterator> ConstReverseValueIterator;
 	
 	typedef boost::transform_iterator<
-		typename Item::template ExtractProperties<Item::Const::No>,
+		typename Item::template ExtractProperties<Const::No>,
 		Iterator> PropertiesIterator;
 	typedef boost::transform_iterator<
-		typename Item::template ExtractProperties<Item::Const::Yes>,
+		typename Item::template ExtractProperties<Const::Yes>,
 		ConstIterator> ConstPropertiesIterator;
 
 	/// Function helper prototype used to display each option on the screen.

src/mpdpp.h

@@ -260,6 +260,23 @@ struct Item
 	{
 		return m_type;
 	}
+
+	Directory &directory()
+	{
+		return const_cast<Directory &>(
+			static_cast<const Item &>(*this).directory());
+	}
+	Song &song()
+	{
+		return const_cast<Song &>(
+			static_cast<const Item &>(*this).song());
+	}
+	Playlist &playlist()
+	{
+		return const_cast<Playlist &>(
+			static_cast<const Item &>(*this).playlist());
+	}
+
 	const Directory &directory() const
 	{
 		assert(m_type == Type::Directory);

src/search_engine.cpp

@@ -73,56 +73,56 @@ namespace pos {
 }*/
 
 std::string SEItemToString(const SEItem &ei);
-bool SEItemEntryMatcher(const Regex::Regex &rx, const NC::Menu<SEItem>::Item &item, bool filter);
-
-template <bool Const>
-struct SongExtractor
-{
-	typedef SongExtractor type;
-
-	typedef typename NC::Menu<SEItem>::Item MenuItem;
-	typedef typename std::conditional<Const, const MenuItem, MenuItem>::type Item;
-	typedef typename std::conditional<Const, const MPD::Song, MPD::Song>::type Song;
-
-	Song *operator()(Item &item) const
-	{
-		Song *ptr = nullptr;
-		if (!item.isSeparator() && item.value().isSong())
-			ptr = &item.value().song();
-		return ptr;
-	}
-};
+bool SEItemEntryMatcher(const Regex::Regex &rx,
+                        const NC::Menu<SEItem>::Item &item,
+                        bool filter);
 
 }
 
+template <>
+struct SongPropertiesExtractor<SEItem>
+{
+	template <typename ItemT>
+	auto &operator()(ItemT &item) const
+	{
+		auto s = !item.isSeparator() && item.value().isSong()
+			? &item.value().song()
+			: nullptr;
+		return m_cache.assign(&item.properties(), s);
+	}
+
+private:
+	mutable SongProperties m_cache;
+};
+
 SongIterator SearchEngineWindow::currentS()
 {
-	return makeSongIterator_<SEItem>(current(), SongExtractor<false>());
+	return makeSongIterator(current());
 }
 
 ConstSongIterator SearchEngineWindow::currentS() const
 {
-	return makeConstSongIterator_<SEItem>(current(), SongExtractor<true>());
+	return makeConstSongIterator(current());
 }
 
 SongIterator SearchEngineWindow::beginS()
 {
-	return makeSongIterator_<SEItem>(begin(), SongExtractor<false>());
+	return makeSongIterator(begin());
 }
 
 ConstSongIterator SearchEngineWindow::beginS() const
 {
-	return makeConstSongIterator_<SEItem>(begin(), SongExtractor<true>());
+	return makeConstSongIterator(begin());
 }
 
 SongIterator SearchEngineWindow::endS()
 {
-	return makeSongIterator_<SEItem>(end(), SongExtractor<false>());
+	return makeSongIterator(end());
 }
 
 ConstSongIterator SearchEngineWindow::endS() const
 {
-	return makeConstSongIterator_<SEItem>(end(), SongExtractor<true>());
+	return makeConstSongIterator(end());
 }
 
 std::vector<MPD::Song> SearchEngineWindow::getSelectedSongs()

src/song_list.cpp

@@ -22,53 +22,34 @@
 #include "song_info.h"
 #include "utility/functional.h"
 
-namespace {
-
-template <bool Const>
-struct SongExtractor
-{
-	typedef SongExtractor type;
-
-	typedef typename NC::Menu<MPD::Song>::Item MenuItem;
-	typedef typename std::conditional<Const, const MenuItem, MenuItem>::type Item;
-	typedef typename std::conditional<Const, const MPD::Song, MPD::Song>::type Song;
-
-	Song *operator()(Item &item) const
-	{
-		return &item.value();
-	}
-};
-
-}
-
 SongIterator SongMenu::currentS()
 {
-	return makeSongIterator_<MPD::Song>(current(), SongExtractor<false>());
+	return makeSongIterator(current());
 }
 
 ConstSongIterator SongMenu::currentS() const
 {
-	return makeConstSongIterator_<MPD::Song>(current(), SongExtractor<true>());
+	return makeConstSongIterator(current());
 }
 
 SongIterator SongMenu::beginS()
 {
-	return makeSongIterator_<MPD::Song>(begin(), SongExtractor<false>());
+	return makeSongIterator(begin());
 }
 
 ConstSongIterator SongMenu::beginS() const
 {
-	return makeConstSongIterator_<MPD::Song>(begin(), SongExtractor<true>());
+	return makeConstSongIterator(begin());
 }
 
 SongIterator SongMenu::endS()
 {
-	return makeSongIterator_<MPD::Song>(end(), SongExtractor<false>());
+	return makeSongIterator(end());
 }
 
 ConstSongIterator SongMenu::endS() const
 {
-	return makeConstSongIterator_<MPD::Song>(end(), SongExtractor<true>());
+	return makeConstSongIterator(end());
 }
 
 std::vector<MPD::Song> SongMenu::getSelectedSongs()

src/song_list.h

@@ -22,25 +22,85 @@
 #define NCMPCPP_SONG_LIST_H
 
 #include <boost/range/detail/any_iterator.hpp>
-#include <boost/tuple/tuple.hpp>
 #include "menu.h"
 #include "song.h"
+#include "utility/const.h"
 
-template <typename ValueT>
+struct SongProperties
+{
+	enum class State { Undefined, Const, Mutable };
+
+	SongProperties()
+		: m_state(State::Undefined)
+	{ }
+
+	SongProperties &assign(NC::List::Properties *properties_, MPD::Song *song_)
+	{
+		m_state = State::Mutable;
+		m_properties = properties_;
+		m_song = song_;
+		return *this;
+	}
+
+	SongProperties &assign(const NC::List::Properties *properties_, const MPD::Song *song_)
+	{
+		m_state = State::Const;
+		m_const_properties = properties_;
+		m_const_song = song_;
+		return *this;
+	}
+
+	const NC::List::Properties &properties() const
+	{
+		assert(m_state != State::Undefined);
+		return *m_const_properties;
+	}
+	const MPD::Song *song() const
+	{
+		assert(m_state != State::Undefined);
+		return m_const_song;
+	}
+
+	NC::List::Properties &properties()
+	{
+		assert(m_state == State::Mutable);
+		return *m_properties;
+	}
+	MPD::Song *song()
+	{
+		assert(m_state == State::Mutable);
+		return m_song;
+	}
+
+private:
+	State m_state;
+
+	union {
+		NC::List::Properties *m_properties;
+		const NC::List::Properties *m_const_properties;
+	};
+	union {
+		MPD::Song *m_song;
+		const MPD::Song *m_const_song;
+	};
+};
+
+template <Const const_>
 using SongIteratorT = boost::range_detail::any_iterator<
-	ValueT,
+	typename std::conditional<
+		const_ == Const::Yes,
+		const SongProperties,
+		SongProperties>::type,
 	boost::random_access_traversal_tag,
-	const ValueT, // const needed, see https://svn.boost.org/trac/boost/ticket/10493
+	typename std::conditional<
+		const_ == Const::Yes,
+		const SongProperties &,
+		SongProperties &>::type,
 	std::ptrdiff_t
->;
+	>;
 
-typedef SongIteratorT<boost::tuple<NC::List::Properties &, MPD::Song *>> SongIterator;
-typedef SongIteratorT<boost::tuple<const NC::List::Properties &, const MPD::Song *>> ConstSongIterator;
-
-namespace Bit {
-const size_t Properties = 0;
-const size_t Song = 1;
-}
+typedef SongIteratorT<Const::No> SongIterator;
+typedef SongIteratorT<Const::Yes> ConstSongIterator;
 
 struct SongList
 {

src/tag_editor.cpp

@@ -87,51 +87,36 @@ std::string SongToString(const MPD::MutableSong &s);
 bool DirEntryMatcher(const Regex::Regex &rx, const std::pair<std::string, std::string> &dir, bool filter);
 bool SongEntryMatcher(const Regex::Regex &rx, const MPD::MutableSong &s);
 
-template <bool Const>
-struct SongExtractor
-{
-	typedef SongExtractor type;
-
-	typedef typename NC::Menu<MPD::MutableSong>::Item MenuItem;
-	typedef typename std::conditional<Const, const MenuItem, MenuItem>::type Item;
-	typedef typename std::conditional<Const, const MPD::Song, MPD::Song>::type Song;
-
-	Song *operator()(Item &item) const
-	{
-		return &item.value();
-	}
-};
-
 }
 
 SongIterator TagsWindow::currentS()
 {
-	return makeSongIterator_<MPD::MutableSong>(current(), SongExtractor<false>());
+	return makeSongIterator(current());
 }
 
 ConstSongIterator TagsWindow::currentS() const
 {
-	return makeConstSongIterator_<MPD::MutableSong>(current(), SongExtractor<true>());
+	return makeConstSongIterator(current());
 }
 
 SongIterator TagsWindow::beginS()
 {
-	return makeSongIterator_<MPD::MutableSong>(begin(), SongExtractor<false>());
+	return makeSongIterator(begin());
 }
 
 ConstSongIterator TagsWindow::beginS() const
 {
-	return makeConstSongIterator_<MPD::MutableSong>(begin(), SongExtractor<true>());
+	return makeConstSongIterator(begin());
 }
 
 SongIterator TagsWindow::endS()
 {
-	return makeSongIterator_<MPD::MutableSong>(end(), SongExtractor<false>());
+	return makeSongIterator(end());
 }
 
 ConstSongIterator TagsWindow::endS() const
 {
-	return makeConstSongIterator_<MPD::MutableSong>(end(), SongExtractor<true>());
+	return makeConstSongIterator(end());
 }
 
 std::vector<MPD::Song> TagsWindow::getSelectedSongs()

src/utility/const.h

@@ -0,0 +1,26 @@
+/***************************************************************************
+ *   Copyright (C) 2008-2016 by Andrzej Rybczak                            *
+ *   electricityispower@gmail.com                                          *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, write to the                         *
+ *   Free Software Foundation, Inc.,                                       *
+ *   51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.              *
+ ***************************************************************************/
+
+#ifndef NCMPCPP_UTILITY_CONST_H
+#define NCMPCPP_UTILITY_CONST_H
+
+enum class Const { Yes, No };
+
+#endif // NCMPCPP_UTILITY_CONST_H