playlist: make reverse operate on iterator range

src/helpers.h

@@ -75,6 +75,21 @@ std::vector<Iterator> getSelected(Iterator first, Iterator last)
 	return result;
 }
 
+/// @return selected range within given range or original range if no item is selected
+template <typename Iterator>
+std::pair<Iterator, Iterator> getSelectedRange(Iterator first, Iterator second)
+{
+	auto result = std::make_pair(first, second);
+	if (hasSelected(first, second))
+	{
+		while (!result.first->isSelected())
+			++result.first;
+		while (!(result.second-1)->isSelected())
+			--result.second;
+	}
+	return result;
+}
+
 template <typename T>
 void selectCurrentIfNoneSelected(NC::Menu<T> &m)
 {

src/playlist.cpp

@@ -223,27 +223,12 @@ bool Playlist::isFiltered()
 
 void Playlist::Reverse()
 {
-	if (isFiltered())
-		return;
 	Statusbar::msg("Reversing playlist order...");
-	size_t beginning = -1, end = -1;
-	for (size_t i = 0; i < w.size(); ++i)
-	{
-		if (w.at(i).isSelected())
-		{
-			if (beginning == size_t(-1))
-				beginning = i;
-			end = i;
-		}
-	}
-	if (beginning == size_t(-1)) // no selected items
-	{
-		beginning = 0;
-		end = w.size();
-	}
+	auto begin = w.begin(), end = w.end();
+	std::tie(begin, end) = getSelectedRange(begin, end);
 	Mpd.StartCommandsList();
-	for (size_t i = beginning, j = end-1; i < (beginning+end)/2; ++i, --j)
-		Mpd.Swap(i, j);
+	for (--end; begin < end; ++begin, --end)
+		Mpd.Swap(begin->value().getPosition(), end->value().getPosition());
 	if (Mpd.CommitCommandsList())
 		 Statusbar::msg("Playlist reversed");
 }

src/sort_playlist.cpp

@@ -155,14 +155,7 @@ void SortPlaylistDialog::sort() const
 {
 	auto &pl = myPlaylist->main();
 	auto begin = pl.begin(), end = pl.end();
-	// if songs are selected, sort range from first selected to last selected
-	if (hasSelected(pl.begin(), pl.end()))
-	{
-		while (!begin->isSelected())
-			++begin;
-		while (!(end-1)->isSelected())
-			--end;
-	}
+	std::tie(begin, end) = getSelectedRange(begin, end);
 	
 	size_t start_pos = begin - pl.begin();
 	MPD::SongList playlist;